From fa42ab7cc5d136d575f84b3b1e75bb093066e3e2 Mon Sep 17 00:00:00 2001
From: Jaime Sanchez <jaimesanchez8@gmail.com>
Date: Mon, 4 Mar 2024 17:39:12 +0100
Subject: [PATCH 1/9] feat: update word placement algo

---
 .../lib/models/data_model.dart                | 260 --------
 .../lib/src/models/data_model.dart            | 557 ++++++++++++++++++
 .../lib/{ => src}/models/data_model.g.dart    |  18 +
 .../{ => src}/models/data_model_test.dart     |  32 +-
 4 files changed, 584 insertions(+), 283 deletions(-)
 delete mode 100644 packages/board_generator/lib/models/data_model.dart
 create mode 100644 packages/board_generator/lib/src/models/data_model.dart
 rename packages/board_generator/lib/{ => src}/models/data_model.g.dart (92%)
 rename packages/board_generator/test/{ => src}/models/data_model_test.dart (85%)

diff --git a/packages/board_generator/lib/models/data_model.dart b/packages/board_generator/lib/models/data_model.dart
deleted file mode 100644
index 0a192f3b2..000000000
--- a/packages/board_generator/lib/models/data_model.dart
+++ /dev/null
@@ -1,260 +0,0 @@
-library data_model;
-
-import 'package:built_collection/built_collection.dart';
-import 'package:built_value/built_value.dart';
-import 'package:characters/characters.dart';
-
-part 'data_model.g.dart';
-
-///{@template crossword}
-/// A crossword puzzle data model.
-/// {@endtemplate}
-abstract class Crossword implements Built<Crossword, CrosswordBuilder> {
-  ///{@macro crossword}
-  factory Crossword([void Function(CrosswordBuilder) updates]) = _$Crossword;
-
-  Crossword._();
-
-  /// The list of unused candidate words that can be added to this crossword.
-  BuiltList<String> get candidates;
-
-  /// The list of down words, by their starting point location
-  BuiltMap<Location, String> get downWords;
-
-  /// The list of across words, by their starting point location
-  BuiltMap<Location, String> get acrossWords;
-
-  /// The characters by location. Useful for displaying the crossword,
-  /// or checking the proposed solution.
-  BuiltMap<Location, CrosswordCharacter> get characters;
-
-  /// Checks if this crossword is valid.
-  bool get valid {
-    for (final entry in characters.entries) {
-      final location = entry.key;
-      final character = entry.value;
-
-      // All characters must be a part of an across or down word.
-      if (character.acrossWord == null && character.downWord == null) {
-        return false;
-      }
-
-      // Characters above and below this character must be related
-      // by a vertical word
-      final characterNorth =
-          characters[location.rebuild((b) => b..down = location.down - 1)];
-      if (characterNorth != null) {
-        if (character.downWord == null) return false;
-        if (characterNorth.downWord != character.downWord) return false;
-      }
-
-      final characterSouth =
-          characters[location.rebuild((b) => b..down = location.down + 1)];
-      if (characterSouth != null) {
-        if (character.downWord == null) return false;
-        if (characterSouth.downWord != character.downWord) return false;
-      }
-
-      // Characters to the left and right of this character must be
-      // related by a horizontal word
-      final characterEast =
-          characters[location.rebuild((b) => b..across = location.across - 1)];
-      if (characterEast != null) {
-        if (character.acrossWord == null) return false;
-        if (characterEast.acrossWord != character.acrossWord) return false;
-      }
-
-      final characterWest =
-          characters[location.rebuild((b) => b..across = location.across + 1)];
-      if (characterWest != null) {
-        if (character.acrossWord == null) return false;
-        if (characterWest.acrossWord != character.acrossWord) return false;
-      }
-    }
-
-    return true;
-  }
-
-  /// Adds a word across to the crossword puzzle, if it fits.
-  Crossword? addAcrossWord({required Location location, required String word}) {
-    final wordCharacters = word.characters;
-
-    for (final (index, character) in wordCharacters.indexed) {
-      final characterLocation =
-          location.rebuild((b) => b.across = b.across! + index);
-      final target = characters[characterLocation];
-      if (target != null) {
-        if (target.character != character) return null;
-        if (target.acrossWord != null) return null;
-      }
-    }
-
-    final updated = rebuild((b) => b.acrossWords.addAll({location: word}));
-    if (updated.valid) return updated;
-    return null;
-  }
-
-  /// Adds a word down to the crossword puzzle, if it fits.
-  Crossword? addDownWord({required Location location, required String word}) {
-    final wordCharacters = word.characters;
-
-    for (final (index, character) in wordCharacters.indexed) {
-      final characterLocation =
-          location.rebuild((b) => b.down = b.down! + index);
-      final target = characters[characterLocation];
-      if (target != null) {
-        if (target.character != character) return null;
-        if (target.downWord != null) return null;
-      }
-    }
-
-    final updated = rebuild((b) => b.downWords.addAll({location: word}));
-    if (updated.valid) return updated;
-    return null;
-  }
-
-  /// Generates a crossword puzzle by adding words to the board.
-  Iterable<Crossword> generate() sync* {
-    // Nothing left to do if there are no candidate words
-    if (candidates.isEmpty) return;
-
-    // Split out the first word case
-    if (downWords.isEmpty && acrossWords.isEmpty) {
-      for (final word in candidates) {
-        final location = Location(
-          (b) => b
-            ..across = 0
-            ..down = 0,
-        );
-
-        yield rebuild((b) => b..candidates.remove(word))
-            .addAcrossWord(location: location, word: word)!;
-      }
-      return;
-    }
-
-    // All subsequent words are joined to previous words
-    for (final entry in characters.entries.toList()..shuffle()) {
-      // ignore locations that already join two words
-      if (entry.value.acrossWord != null && entry.value.downWord != null) {
-        continue;
-      }
-
-      // Filter down the candidate word list to those that contain the letter
-      // at the current location
-      final filteredCandidates = candidates.rebuild(
-        (b) => b.removeWhere(
-          (innerWord) => !innerWord.characters.contains(entry.value.character),
-        ),
-      );
-
-      // Attempt to place the filtered candidate words over the current
-      // location as a join point.
-      for (final word in filteredCandidates) {
-        for (final (index, character) in word.characters.indexed) {
-          if (character != entry.value.character) continue;
-
-          if (entry.value.acrossWord != null) {
-            // Adding a downWord
-            final candidate =
-                rebuild((b) => b..candidates.remove(word)).addDownWord(
-              location:
-                  entry.key.rebuild((b) => b.down = entry.key.down - index),
-              word: word,
-            );
-
-            if (candidate != null) yield candidate;
-          } else {
-            // Adding an acrossWord
-            final candidate =
-                rebuild((b) => b..candidates.remove(word)).addAcrossWord(
-              location:
-                  entry.key.rebuild((b) => b.across = entry.key.across - index),
-              word: word,
-            );
-
-            if (candidate != null) yield candidate;
-          }
-        }
-      }
-    }
-  }
-
-  @BuiltValueHook(finalizeBuilder: true)
-  static void _fillCharacters(CrosswordBuilder b) {
-    b.characters.clear();
-
-    for (final entry in b.acrossWords.build().entries) {
-      final location = entry.key;
-      final word = entry.value;
-      for (final (idx, character) in word.characters.indexed) {
-        final characterLocation =
-            location.rebuild((b) => b..across = location.across + idx);
-        b.characters.putIfAbsent(
-          characterLocation,
-          () => CrosswordCharacter(
-            (b) => b
-              ..acrossWord = word
-              ..character = character,
-          ),
-        );
-      }
-    }
-
-    for (final entry in b.downWords.build().entries) {
-      final location = entry.key;
-      final word = entry.value;
-      for (final (idx, character) in word.characters.indexed) {
-        final characterLocation =
-            location.rebuild((b) => b..down = location.down + idx);
-        b.characters.updateValue(
-          characterLocation,
-          (b) => b.rebuild((b) => b.downWord = word),
-          ifAbsent: () => CrosswordCharacter(
-            (b) => b
-              ..downWord = word
-              ..character = character,
-          ),
-        );
-      }
-    }
-  }
-}
-
-///{@template location}
-/// A location in the crossword puzzle.
-/// {@endtemplate}
-abstract class Location implements Built<Location, LocationBuilder> {
-  ///{@macro location}
-  factory Location([void Function(LocationBuilder) updates]) = _$Location;
-
-  Location._();
-
-  /// The horizontal part of the location.
-  int get across;
-
-  /// The vertical part of the location.
-  int get down;
-}
-
-///{@template crossword_character}
-/// A character in the crossword puzzle.
-/// {@endtemplate}
-abstract class CrosswordCharacter
-    implements Built<CrosswordCharacter, CrosswordCharacterBuilder> {
-  ///{@macro crossword_character}
-  factory CrosswordCharacter([
-    void Function(CrosswordCharacterBuilder) updates,
-  ]) = _$CrosswordCharacter;
-
-  CrosswordCharacter._();
-
-  /// The character at this location.
-  String get character;
-
-  /// The across word that this character is a part of.
-  String? get acrossWord;
-
-  /// The down word that this character is a part of.
-  String? get downWord;
-}
diff --git a/packages/board_generator/lib/src/models/data_model.dart b/packages/board_generator/lib/src/models/data_model.dart
new file mode 100644
index 000000000..d5d7d29af
--- /dev/null
+++ b/packages/board_generator/lib/src/models/data_model.dart
@@ -0,0 +1,557 @@
+library data_model;
+
+import 'package:built_collection/built_collection.dart';
+import 'package:built_value/built_value.dart';
+import 'package:characters/characters.dart';
+
+part 'data_model.g.dart';
+
+///{@template crossword}
+/// A crossword puzzle data model.
+/// {@endtemplate}
+abstract class Crossword implements Built<Crossword, CrosswordBuilder> {
+  ///{@macro crossword}
+  factory Crossword([void Function(CrosswordBuilder) updates]) = _$Crossword;
+
+  Crossword._();
+
+  /// The list of unused candidate words that can be added to this crossword.
+  BuiltList<String> get candidates;
+
+  /// The list of candidate locations to process.
+  BuiltList<Location> get candidateLocations;
+
+  /// The list of down words, by their starting point location
+  BuiltMap<Location, String> get downWords;
+
+  /// The list of across words, by their starting point location
+  BuiltMap<Location, String> get acrossWords;
+
+  /// The characters by location. Useful for displaying the crossword,
+  /// or checking the proposed solution.
+  BuiltMap<Location, CrosswordCharacter> get characters;
+
+  /// Checks if this crossword is valid.
+  bool get valid {
+    for (final entry in characters.entries) {
+      final location = entry.key;
+      final character = entry.value;
+
+      // All characters must be a part of an across or down word.
+      if (character.acrossWord == null && character.downWord == null) {
+        return false;
+      }
+
+      // Characters above and below this character must be related
+      // by a vertical word
+      final characterNorth =
+          characters[location.rebuild((b) => b..down = location.down - 1)];
+      if (characterNorth != null) {
+        if (character.downWord == null) return false;
+        if (characterNorth.downWord != character.downWord) return false;
+      }
+
+      final characterSouth =
+          characters[location.rebuild((b) => b..down = location.down + 1)];
+      if (characterSouth != null) {
+        if (character.downWord == null) return false;
+        if (characterSouth.downWord != character.downWord) return false;
+      }
+
+      // Characters to the left and right of this character must be
+      // related by a horizontal word
+      final characterEast =
+          characters[location.rebuild((b) => b..across = location.across - 1)];
+      if (characterEast != null) {
+        if (character.acrossWord == null) return false;
+        if (characterEast.acrossWord != character.acrossWord) return false;
+      }
+
+      final characterWest =
+          characters[location.rebuild((b) => b..across = location.across + 1)];
+      if (characterWest != null) {
+        if (character.acrossWord == null) return false;
+        if (characterWest.acrossWord != character.acrossWord) return false;
+      }
+    }
+
+    return true;
+  }
+
+  /// Adds a word across to the crossword puzzle, if it fits.
+  Crossword? addAcrossWord({required Location location, required String word}) {
+    final wordCharacters = word.characters;
+    final characterLocations = <Location>[];
+
+    for (final (index, character) in wordCharacters.indexed) {
+      final characterLocation =
+          location.rebuild((b) => b.across = b.across! + index);
+      characterLocations.add(characterLocation);
+      final target = characters[characterLocation];
+      if (target != null) {
+        if (target.character != character) return null;
+        if (target.acrossWord != null) return null;
+      }
+    }
+
+    final updated = rebuild(
+      (b) => b
+        ..acrossWords.addAll({location: word})
+        ..candidateLocations.addAll(characterLocations),
+    );
+    if (updated.valid) return updated;
+    return null;
+  }
+
+  /// Adds a word down to the crossword puzzle, if it fits.
+  Crossword? addDownWord({required Location location, required String word}) {
+    final wordCharacters = word.characters;
+    final characterLocations = <Location>[];
+
+    for (final (index, character) in wordCharacters.indexed) {
+      final characterLocation =
+          location.rebuild((b) => b.down = b.down! + index);
+      characterLocations.add(characterLocation);
+      final target = characters[characterLocation];
+      if (target != null) {
+        if (target.character != character) return null;
+        if (target.downWord != null) return null;
+      }
+    }
+
+    final updated = rebuild(
+      (b) => b
+        ..downWords.addAll({location: word})
+        ..candidateLocations.addAll(characterLocations),
+    );
+    if (updated.valid) return updated;
+    return null;
+  }
+
+  /// Generates a crossword puzzle by adding words to the board.
+  Crossword generate() {
+    // Nothing left to do if there are no candidate words
+    if (candidates.isEmpty) return this;
+
+    // Split out the first word case
+    if (downWords.isEmpty && acrossWords.isEmpty) {
+      for (final word in candidates) {
+        final location = Location(
+          (b) => b
+            ..across = 0
+            ..down = 0,
+        );
+
+        return rebuild((b) => b..candidates.remove(word))
+            .addAcrossWord(location: location, word: word)!;
+      }
+      return this;
+    }
+
+    const radius = 5;
+    const maxNeighbors = 20;
+    // Use the locations that have a higher probability of fitting a word.
+    // Keep the locations that have less characters around them.
+    final filteredLocations = candidateLocations.rebuild(
+      (b) => b.removeWhere((e) {
+        final neighbors = <CrosswordCharacter>[];
+        for (var i = e.across - radius; i <= e.across + radius; i++) {
+          for (var j = e.down - radius; j <= e.down + radius; j++) {
+            final location = Location(
+              (b) => b
+                ..across = i
+                ..down = j,
+            );
+            final character = characters[location];
+            if (character != null) {
+              neighbors.add(character);
+            }
+          }
+        }
+        return neighbors.length > maxNeighbors;
+      }),
+    );
+
+    // All subsequent words are joined to previous words
+    var locations = filteredLocations.rebuild((b) => b.shuffle());
+    while (locations.isNotEmpty) {
+      final location = locations.first;
+      locations = locations.rebuild((b) => b.remove(location));
+      final target = characters[location]!;
+
+      // ignore locations that already join two words
+      if (target.acrossWord != null && target.downWord != null) {
+        continue;
+      }
+
+      // Skip locations that have neighbors that join two words
+      final characterEast =
+          characters[location.rebuild((b) => b..across = location.across + 1)];
+      if (characterEast != null && characterEast.downWord != null) {
+        continue;
+      }
+      final characterWest =
+          characters[location.rebuild((b) => b..across = location.across - 1)];
+      if (characterWest != null && characterWest.downWord != null) {
+        continue;
+      }
+      final characterNorth =
+          characters[location.rebuild((b) => b..down = location.down - 1)];
+      if (characterNorth != null && characterNorth.acrossWord != null) {
+        continue;
+      }
+      final characterSouth =
+          characters[location.rebuild((b) => b..down = location.down + 1)];
+      if (characterSouth != null && characterSouth.acrossWord != null) {
+        continue;
+      }
+
+      // Get the maximum word length that can be placed at this location
+      final (wordEnd, wordStart, letters) = _getMaxWordLength(location);
+      final maxWordLength = wordEnd - wordStart;
+
+      // Filter down the candidate word list to those that contain the letter
+      // at the current location
+      final filteredCandidates = candidates.rebuild(
+        (b) => b.where(
+          (innerWord) =>
+              innerWord.characters.contains(target.character) &&
+              innerWord.length <= maxWordLength &&
+              innerWord.characters.containsAll(letters.join().characters),
+        ),
+      );
+
+      // Attempt to place the filtered candidate words over the current
+      // location as a join point.
+      for (final word in filteredCandidates) {
+        for (final (index, character) in word.characters.indexed) {
+          if (character != target.character) continue;
+
+          if (target.acrossWord != null) {
+            // Adding a downWord
+            final candidate = rebuild(
+              (b) => b
+                ..candidates.remove(word)
+                ..candidateLocations.replace(locations),
+            ).addDownWord(
+              location: location.rebuild((b) => b.down = location.down - index),
+              word: word,
+            );
+
+            if (candidate != null) return candidate;
+          } else {
+            // Adding an acrossWord
+            final candidate = rebuild(
+              (b) => b
+                ..candidates.remove(word)
+                ..candidateLocations.replace(locations),
+            ).addAcrossWord(
+              location:
+                  location.rebuild((b) => b.across = location.across - index),
+              word: word,
+            );
+
+            if (candidate != null) return candidate;
+          }
+        }
+      }
+    }
+    return this;
+  }
+
+  @BuiltValueHook(finalizeBuilder: true)
+  static void _fillCharacters(CrosswordBuilder b) {
+    b.characters.clear();
+
+    for (final entry in b.acrossWords.build().entries) {
+      final location = entry.key;
+      final word = entry.value;
+      for (final (idx, character) in word.characters.indexed) {
+        final characterLocation =
+            location.rebuild((b) => b..across = location.across + idx);
+        b.characters.putIfAbsent(
+          characterLocation,
+          () => CrosswordCharacter(
+            (b) => b
+              ..acrossWord = word
+              ..character = character,
+          ),
+        );
+      }
+    }
+
+    for (final entry in b.downWords.build().entries) {
+      final location = entry.key;
+      final word = entry.value;
+      for (final (idx, character) in word.characters.indexed) {
+        final characterLocation =
+            location.rebuild((b) => b..down = location.down + idx);
+        b.characters.updateValue(
+          characterLocation,
+          (b) => b.rebuild((b) => b.downWord = word),
+          ifAbsent: () => CrosswordCharacter(
+            (b) => b
+              ..downWord = word
+              ..character = character,
+          ),
+        );
+      }
+    }
+  }
+
+  (int, int, Set<String>) _getMaxWordLength(Location location) {
+    final target = characters[location]!;
+    if (target.acrossWord != null) {
+      final (startBoundary, startLetters) = _getDownStartBoundary(location);
+      final (endBoundary, endLetters) = _getDownEndBoundary(location);
+      final letters = startLetters.union(endLetters);
+      return (endBoundary, startBoundary, letters);
+    } else {
+      final (startBoundary, startLetters) = _getAcrossStartBoundary(location);
+      final (endBoundary, endLetters) = _getAcrossEndBoundary(location);
+      final letters = startLetters.union(endLetters);
+      return (endBoundary, startBoundary, letters);
+    }
+  }
+
+  (int, Set<String>) _getDownStartBoundary(Location location) {
+    final letters = <String>{};
+    var startBoundary = location.down;
+    final down = location.down;
+    for (var i = down; i >= down - 20; i--) {
+      final westTarget = characters[location.rebuild(
+        (b) => b
+          ..down = i
+          ..across = location.across - 1,
+      )];
+      final target = characters[location.rebuild((b) => b..down = i - 1)];
+      final eastTarget = characters[location.rebuild(
+        (b) => b
+          ..down = i
+          ..across = location.across + 1,
+      )];
+
+      // Avoid adding a word parallel to another or that extends another word
+      if ((westTarget?.downWord != null) ||
+          (target?.downWord != null) ||
+          (eastTarget?.downWord != null)) break;
+
+      final northWestTarget = characters[location.rebuild(
+        (b) => b
+          ..down = i - 1
+          ..across = location.across - 1,
+      )];
+      final northEastTarget = characters[location.rebuild(
+        (b) => b
+          ..down = i - 1
+          ..across = location.across + 1,
+      )];
+
+      // Avoid adding a word that extends other word by one character
+      final hasDiagonalNeighbor = (northWestTarget?.acrossWord != null) ||
+          (northEastTarget?.acrossWord != null);
+      if (hasDiagonalNeighbor && (target?.acrossWord == null)) {
+        break;
+      }
+
+      // If the target contains a character, add it to the list of letters
+      // that can be used to filter the candidate words
+      final distance = (down - i).abs();
+      if ((target != null) && (distance < 4)) {
+        letters.add(target.character);
+      }
+      startBoundary = i;
+    }
+    return (startBoundary, letters);
+  }
+
+  (int, Set<String>) _getDownEndBoundary(Location location) {
+    final letters = <String>{};
+    var endBoundary = location.down;
+    final down = location.down;
+    for (var i = down; i <= down + 20; i++) {
+      final westTarget = characters[location.rebuild(
+        (b) => b
+          ..down = i
+          ..across = location.across - 1,
+      )];
+      final target = characters[location.rebuild((b) => b..down = i + 1)];
+      final eastTarget = characters[location.rebuild(
+        (b) => b
+          ..down = i
+          ..across = location.across + 1,
+      )];
+
+      // Avoid adding a word parallel to another or that extends another word
+      if ((westTarget?.downWord != null) ||
+          (target?.downWord != null) ||
+          (eastTarget?.downWord != null)) break;
+
+      final southEastTarget = characters[location.rebuild(
+        (b) => b
+          ..down = i + 1
+          ..across = location.across + 1,
+      )];
+      final southWestTarget = characters[location.rebuild(
+        (b) => b
+          ..down = i + 1
+          ..across = location.across - 1,
+      )];
+
+      // Avoid adding a word that extends other word by one character
+      final hasDiagonalNeighbor = (southEastTarget?.acrossWord != null) ||
+          (southWestTarget?.acrossWord != null);
+      if (hasDiagonalNeighbor && (target?.acrossWord == null)) {
+        break;
+      }
+
+      // If the target contains a character, add it to the list of letters
+      // that can be used to filter the candidate words
+      final distance = (down - i).abs();
+      if ((target != null) && (distance < 4)) {
+        letters.add(target.character);
+      }
+      endBoundary = i;
+    }
+    return (endBoundary, letters);
+  }
+
+  (int, Set<String>) _getAcrossStartBoundary(Location location) {
+    final letters = <String>{};
+    var startBoundary = location.across;
+    final across = location.across;
+    for (var i = across; i >= across - 20; i--) {
+      final northTarget = characters[location.rebuild(
+        (b) => b
+          ..across = i
+          ..down = location.down - 1,
+      )];
+      final target = characters[location.rebuild((b) => b..across = i - 1)];
+      final southTarget = characters[location.rebuild(
+        (b) => b
+          ..across = i
+          ..down = location.down + 1,
+      )];
+
+      // Avoid adding a word parallel to another or that extends another word
+      if ((northTarget?.acrossWord != null) ||
+          (target?.acrossWord != null) ||
+          (southTarget?.acrossWord != null)) break;
+
+      final northWestTarget = characters[location.rebuild(
+        (b) => b
+          ..across = i - 1
+          ..down = location.down - 1,
+      )];
+      final southWestTarget = characters[location.rebuild(
+        (b) => b
+          ..across = i - 1
+          ..down = location.down + 1,
+      )];
+
+      // Avoid adding a word that extends other word by one character
+      final hasDiagonalNeighbor = (northWestTarget?.downWord != null) ||
+          (southWestTarget?.downWord != null);
+      if (hasDiagonalNeighbor && (target?.downWord == null)) {
+        break;
+      }
+
+      // If the target contains a character, add it to the list of letters
+      // that can be used to filter the candidate words
+      final distance = (across - i).abs();
+      if ((target != null) && (distance < 4)) {
+        letters.add(target.character);
+      }
+      startBoundary = i;
+    }
+    return (startBoundary, letters);
+  }
+
+  (int, Set<String>) _getAcrossEndBoundary(Location location) {
+    final letters = <String>{};
+    var endBoundary = location.across;
+    final across = location.across;
+    for (var i = across; i <= across + 20; i++) {
+      final northTarget = characters[location.rebuild(
+        (b) => b
+          ..across = i
+          ..down = location.down - 1,
+      )];
+      final target = characters[location.rebuild((b) => b..across = i + 1)];
+      final southTarget = characters[location.rebuild(
+        (b) => b
+          ..across = i
+          ..down = location.down + 1,
+      )];
+
+      // Avoid adding a word parallel to another or that extends another word
+      if ((northTarget?.acrossWord != null) ||
+          (target?.acrossWord != null) ||
+          (southTarget?.acrossWord != null)) break;
+      final northEastTarget = characters[location.rebuild(
+        (b) => b
+          ..across = i + 1
+          ..down = location.down - 1,
+      )];
+      final southEastTarget = characters[location.rebuild(
+        (b) => b
+          ..across = i + 1
+          ..down = location.down + 1,
+      )];
+
+      // Avoid adding a word that extends other word by one character
+      final hasDiagonalNeighbor = (northEastTarget?.downWord != null) ||
+          (southEastTarget?.downWord != null);
+      if (hasDiagonalNeighbor && (target?.downWord == null)) {
+        break;
+      }
+
+      // If the target contains a character, add it to the list of letters
+      // that can be used to filter the candidate words
+      final distance = (across - i).abs();
+      if ((target != null) && (distance < 4)) {
+        letters.add(target.character);
+      }
+      endBoundary = i;
+    }
+    return (endBoundary, letters);
+  }
+}
+
+///{@template location}
+/// A location in the crossword puzzle.
+/// {@endtemplate}
+abstract class Location implements Built<Location, LocationBuilder> {
+  ///{@macro location}
+  factory Location([void Function(LocationBuilder) updates]) = _$Location;
+
+  Location._();
+
+  /// The horizontal part of the location.
+  int get across;
+
+  /// The vertical part of the location.
+  int get down;
+}
+
+///{@template crossword_character}
+/// A character in the crossword puzzle.
+/// {@endtemplate}
+abstract class CrosswordCharacter
+    implements Built<CrosswordCharacter, CrosswordCharacterBuilder> {
+  ///{@macro crossword_character}
+  factory CrosswordCharacter([
+    void Function(CrosswordCharacterBuilder) updates,
+  ]) = _$CrosswordCharacter;
+
+  CrosswordCharacter._();
+
+  /// The character at this location.
+  String get character;
+
+  /// The across word that this character is a part of.
+  String? get acrossWord;
+
+  /// The down word that this character is a part of.
+  String? get downWord;
+}
diff --git a/packages/board_generator/lib/models/data_model.g.dart b/packages/board_generator/lib/src/models/data_model.g.dart
similarity index 92%
rename from packages/board_generator/lib/models/data_model.g.dart
rename to packages/board_generator/lib/src/models/data_model.g.dart
index 042e13457..37581e23f 100644
--- a/packages/board_generator/lib/models/data_model.g.dart
+++ b/packages/board_generator/lib/src/models/data_model.g.dart
@@ -10,6 +10,8 @@ class _$Crossword extends Crossword {
   @override
   final BuiltList<String> candidates;
   @override
+  final BuiltList<Location> candidateLocations;
+  @override
   final BuiltMap<Location, String> downWords;
   @override
   final BuiltMap<Location, String> acrossWords;
@@ -21,12 +23,15 @@ class _$Crossword extends Crossword {
 
   _$Crossword._(
       {required this.candidates,
+      required this.candidateLocations,
       required this.downWords,
       required this.acrossWords,
       required this.characters})
       : super._() {
     BuiltValueNullFieldError.checkNotNull(
         candidates, r'Crossword', 'candidates');
+    BuiltValueNullFieldError.checkNotNull(
+        candidateLocations, r'Crossword', 'candidateLocations');
     BuiltValueNullFieldError.checkNotNull(downWords, r'Crossword', 'downWords');
     BuiltValueNullFieldError.checkNotNull(
         acrossWords, r'Crossword', 'acrossWords');
@@ -46,6 +51,7 @@ class _$Crossword extends Crossword {
     if (identical(other, this)) return true;
     return other is Crossword &&
         candidates == other.candidates &&
+        candidateLocations == other.candidateLocations &&
         downWords == other.downWords &&
         acrossWords == other.acrossWords &&
         characters == other.characters;
@@ -55,6 +61,7 @@ class _$Crossword extends Crossword {
   int get hashCode {
     var _$hash = 0;
     _$hash = $jc(_$hash, candidates.hashCode);
+    _$hash = $jc(_$hash, candidateLocations.hashCode);
     _$hash = $jc(_$hash, downWords.hashCode);
     _$hash = $jc(_$hash, acrossWords.hashCode);
     _$hash = $jc(_$hash, characters.hashCode);
@@ -66,6 +73,7 @@ class _$Crossword extends Crossword {
   String toString() {
     return (newBuiltValueToStringHelper(r'Crossword')
           ..add('candidates', candidates)
+          ..add('candidateLocations', candidateLocations)
           ..add('downWords', downWords)
           ..add('acrossWords', acrossWords)
           ..add('characters', characters))
@@ -82,6 +90,12 @@ class CrosswordBuilder implements Builder<Crossword, CrosswordBuilder> {
   set candidates(ListBuilder<String>? candidates) =>
       _$this._candidates = candidates;
 
+  ListBuilder<Location>? _candidateLocations;
+  ListBuilder<Location> get candidateLocations =>
+      _$this._candidateLocations ??= new ListBuilder<Location>();
+  set candidateLocations(ListBuilder<Location>? candidateLocations) =>
+      _$this._candidateLocations = candidateLocations;
+
   MapBuilder<Location, String>? _downWords;
   MapBuilder<Location, String> get downWords =>
       _$this._downWords ??= new MapBuilder<Location, String>();
@@ -106,6 +120,7 @@ class CrosswordBuilder implements Builder<Crossword, CrosswordBuilder> {
     final $v = _$v;
     if ($v != null) {
       _candidates = $v.candidates.toBuilder();
+      _candidateLocations = $v.candidateLocations.toBuilder();
       _downWords = $v.downWords.toBuilder();
       _acrossWords = $v.acrossWords.toBuilder();
       _characters = $v.characters.toBuilder();
@@ -135,6 +150,7 @@ class CrosswordBuilder implements Builder<Crossword, CrosswordBuilder> {
       _$result = _$v ??
           new _$Crossword._(
               candidates: candidates.build(),
+              candidateLocations: candidateLocations.build(),
               downWords: downWords.build(),
               acrossWords: acrossWords.build(),
               characters: characters.build());
@@ -143,6 +159,8 @@ class CrosswordBuilder implements Builder<Crossword, CrosswordBuilder> {
       try {
         _$failedField = 'candidates';
         candidates.build();
+        _$failedField = 'candidateLocations';
+        candidateLocations.build();
         _$failedField = 'downWords';
         downWords.build();
         _$failedField = 'acrossWords';
diff --git a/packages/board_generator/test/models/data_model_test.dart b/packages/board_generator/test/src/models/data_model_test.dart
similarity index 85%
rename from packages/board_generator/test/models/data_model_test.dart
rename to packages/board_generator/test/src/models/data_model_test.dart
index 68b02715d..2dd5d8ca3 100644
--- a/packages/board_generator/test/models/data_model_test.dart
+++ b/packages/board_generator/test/src/models/data_model_test.dart
@@ -1,4 +1,4 @@
-import 'package:board_generator/models/data_model.dart';
+import 'package:board_generator/src/models/data_model.dart';
 import 'package:test/test.dart';
 
 void main() {
@@ -177,59 +177,45 @@ void main() {
       (b) => b..candidates.addAll(wordList),
     );
 
-    final crossword1 = crossword0.generate().first;
+    final crossword1 = crossword0.generate();
     expect(crossword1.valid, true);
     expect(crossword1.acrossWords.length, 1);
     expect(crossword1.candidates.length, crossword0.candidates.length - 1);
 
-    final crossword2 = crossword1.generate().first;
+    final crossword2 = crossword1.generate();
     expect(crossword2.valid, true);
     expect(crossword2.acrossWords.length, 1);
     expect(crossword2.downWords.length, 1);
     expect(crossword2.candidates.length, crossword1.candidates.length - 1);
 
-    final crossword3 = crossword2.generate().first;
+    final crossword3 = crossword2.generate();
     expect(crossword3.valid, true);
     expect(crossword3.acrossWords.length + crossword3.downWords.length, 3);
     expect(crossword3.candidates.length, crossword2.candidates.length - 1);
 
-    final crossword4 = crossword3.generate().first;
+    final crossword4 = crossword3.generate();
     expect(crossword4.valid, true);
     expect(crossword4.acrossWords.length + crossword4.downWords.length, 4);
     expect(crossword4.candidates.length, crossword3.candidates.length - 1);
 
-    final crossword5 = crossword4.generate().first;
+    final crossword5 = crossword4.generate();
     expect(crossword5.valid, true);
     expect(crossword5.acrossWords.length + crossword5.downWords.length, 5);
     expect(crossword5.candidates.length, crossword4.candidates.length - 1);
 
-    final crossword6 = crossword5.generate().first;
+    final crossword6 = crossword5.generate();
     expect(crossword6.valid, true);
     expect(crossword6.acrossWords.length + crossword6.downWords.length, 6);
     expect(crossword6.candidates.length, crossword5.candidates.length - 1);
 
-    final crossword7 = crossword6.generate().first;
+    final crossword7 = crossword6.generate();
     expect(crossword7.valid, true);
     expect(crossword7.acrossWords.length + crossword7.downWords.length, 7);
     expect(crossword7.candidates.length, crossword6.candidates.length - 1);
 
-    final iterable = crossword7.generate();
-    expect(iterable.isEmpty, false);
-    expect(iterable.isNotEmpty, true);
-
-    final iterator = iterable.iterator;
-    expect(iterator.moveNext(), true);
-    expect(iterator.current, isNotNull);
-    final crossword8 = iterator.current;
+    final crossword8 = crossword7.generate();
     expect(crossword8.valid, true);
     expect(crossword8.acrossWords.length + crossword8.downWords.length, 8);
     expect(crossword8.candidates.length, crossword7.candidates.length - 1);
-
-    expect(iterator.moveNext(), true);
-    expect(iterator.current, isNotNull);
-    final crossword9 = iterator.current;
-    expect(crossword9.valid, true);
-    expect(crossword9.acrossWords.length + crossword9.downWords.length, 8);
-    expect(crossword9.candidates.length, crossword7.candidates.length - 1);
   });
 }

From 1c452d15603778659ec39208b91ef19b93438308 Mon Sep 17 00:00:00 2001
From: Jaime Sanchez <jaimesanchez8@gmail.com>
Date: Mon, 4 Mar 2024 17:39:40 +0100
Subject: [PATCH 2/9] feat: update board saving and logging

---
 .../board_generator/lib/board_generator.dart  | 24 --------
 .../lib/src/board_generator.dart              | 57 +++++++++++++++++++
 .../test/{ => src}/board_generator_test.dart  | 20 +++----
 3 files changed, 66 insertions(+), 35 deletions(-)
 delete mode 100644 packages/board_generator/lib/board_generator.dart
 create mode 100644 packages/board_generator/lib/src/board_generator.dart
 rename packages/board_generator/test/{ => src}/board_generator_test.dart (55%)

diff --git a/packages/board_generator/lib/board_generator.dart b/packages/board_generator/lib/board_generator.dart
deleted file mode 100644
index dd55a7866..000000000
--- a/packages/board_generator/lib/board_generator.dart
+++ /dev/null
@@ -1,24 +0,0 @@
-import 'dart:collection';
-
-import 'package:board_generator/models/data_model.dart';
-
-/// Generates a crossword.
-Iterable<Crossword> generateCrosswords(List<String> wordList) sync* {
-  final queue = Queue<Iterator<Crossword>>()
-    ..addFirst(
-      Crossword(
-        (b) => b..candidates.addAll(wordList),
-      ).generate().iterator,
-    );
-
-  while (queue.isNotEmpty) {
-    final iterator = queue.removeFirst();
-    if (iterator.moveNext()) {
-      final crossword = iterator.current;
-      yield crossword;
-      queue
-        ..addFirst(iterator)
-        ..addFirst(crossword.generate().iterator);
-    }
-  }
-}
diff --git a/packages/board_generator/lib/src/board_generator.dart b/packages/board_generator/lib/src/board_generator.dart
new file mode 100644
index 000000000..cf68e5755
--- /dev/null
+++ b/packages/board_generator/lib/src/board_generator.dart
@@ -0,0 +1,57 @@
+// ignore_for_file: avoid_print
+
+import 'dart:io';
+
+import 'package:board_generator/src/models/data_model.dart';
+
+/// Generates a crossword.
+Crossword generateCrossword(List<String> wordList, String filePath) {
+  var crossword = Crossword((b) => b..candidates.addAll(wordList)).generate();
+
+  final before = DateTime.now();
+
+  final file = File(filePath);
+  final savedDownWords = <Location, String>{};
+  final savedAcrossWords = <Location, String>{};
+
+  while (crossword.candidates.isNotEmpty) {
+    crossword = crossword.generate();
+
+    // Save the words to a file. Only save every 100 words to avoid
+    // slowing down the process.
+    final wordCount = crossword.downWords.length + crossword.acrossWords.length;
+    if ((wordCount % 100 == 0) || (wordCount == wordList.length)) {
+      final now = DateTime.now();
+
+      print('Generated $wordCount words in ${now.difference(before)}');
+      print('Candidate locations: ${crossword.candidateLocations.length}');
+
+      final newAcrossWords = crossword.acrossWords.rebuild(
+        (b) =>
+            b..removeWhere((key, value) => savedAcrossWords.containsKey(key)),
+      );
+      final newDownWords = crossword.downWords.rebuild(
+        (b) => b..removeWhere((key, value) => savedDownWords.containsKey(key)),
+      );
+
+      final buffer = StringBuffer();
+      for (final entry in newAcrossWords.entries) {
+        buffer.writeln(
+          '${entry.key.across},${entry.key.down},${entry.value},horizontal',
+        );
+      }
+      for (final entry in newDownWords.entries) {
+        buffer.writeln(
+          '${entry.key.across},${entry.key.down},${entry.value},vertical',
+        );
+      }
+
+      file.writeAsStringSync(buffer.toString(), mode: FileMode.append);
+
+      savedAcrossWords.addAll(newAcrossWords.asMap());
+      savedDownWords.addAll(newDownWords.asMap());
+    }
+  }
+
+  return crossword;
+}
diff --git a/packages/board_generator/test/board_generator_test.dart b/packages/board_generator/test/src/board_generator_test.dart
similarity index 55%
rename from packages/board_generator/test/board_generator_test.dart
rename to packages/board_generator/test/src/board_generator_test.dart
index 745c1246d..29300aa54 100644
--- a/packages/board_generator/test/board_generator_test.dart
+++ b/packages/board_generator/test/src/board_generator_test.dart
@@ -1,5 +1,7 @@
 // ignore_for_file: prefer_const_constructors
-import 'package:board_generator/board_generator.dart';
+import 'dart:io';
+
+import 'package:board_generator/src/board_generator.dart';
 import 'package:test/test.dart';
 
 void main() {
@@ -23,16 +25,12 @@ void main() {
 
   group('BoardGenerator', () {
     test('generate crosswords', () {
-      var depth = 0;
-      for (final crossword in generateCrosswords(wordList)) {
-        depth++;
-        expect(crossword.valid, true);
-        expect(
-          crossword.acrossWords.length + crossword.downWords.length,
-          depth,
-        );
-        if (depth >= wordList.length) break;
-      }
+      final crossword = generateCrossword(wordList, 'test-board.txt');
+
+      final size = crossword.acrossWords.length + crossword.downWords.length;
+      expect(size, wordList.length);
+
+      File('test-board.txt').deleteSync();
     });
   });
 }

From ab930e8dbb48622596995bdf0d2296a6326f0745 Mon Sep 17 00:00:00 2001
From: Jaime Sanchez <jaimesanchez8@gmail.com>
Date: Mon, 4 Mar 2024 17:40:12 +0100
Subject: [PATCH 3/9] feat: save board to firestore

---
 .../lib/src/crossword_repository.dart         | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 packages/board_generator/lib/src/crossword_repository.dart

diff --git a/packages/board_generator/lib/src/crossword_repository.dart b/packages/board_generator/lib/src/crossword_repository.dart
new file mode 100644
index 000000000..672311a92
--- /dev/null
+++ b/packages/board_generator/lib/src/crossword_repository.dart
@@ -0,0 +1,33 @@
+import 'package:dart_firebase_admin/firestore.dart';
+import 'package:game_domain/game_domain.dart';
+
+/// {@template crossword_repository}
+/// Repository for interacting with the crossword database in a dart only env.
+/// {@endtemplate}
+class CrosswordRepository {
+  /// {@macro crossword_repository}
+  CrosswordRepository({required this.firestore});
+
+  /// The firestore instance.
+  final Firestore firestore;
+
+  /// Adds a list of sections to the database.
+  Future<void> addSections(List<BoardSection> sections) async {
+    for (final section in sections) {
+      await firestore.collection('boardSections').add(section.toJson());
+    }
+  }
+
+  /// Deletes all sections from the database.
+  Future<void> deleteSections() async {
+    var docs = await firestore.collection('boardSections').listDocuments();
+    var length = docs.length;
+    while (length > 0) {
+      for (final doc in docs) {
+        await doc.delete();
+      }
+      docs = await firestore.collection('boardSections').listDocuments();
+      length = docs.length;
+    }
+  }
+}

From b5d505464047d685a4f27e81952820b23dfdfd0b Mon Sep 17 00:00:00 2001
From: Jaime Sanchez <jaimesanchez8@gmail.com>
Date: Mon, 4 Mar 2024 18:10:56 +0100
Subject: [PATCH 4/9] chore: add models package

---
 .github/workflows/board_generator.yaml | 1 +
 packages/board_generator/.gitignore    | 5 ++++-
 packages/board_generator/pubspec.yaml  | 4 ++++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/board_generator.yaml b/.github/workflows/board_generator.yaml
index 3677a5edb..f91970f85 100644
--- a/.github/workflows/board_generator.yaml
+++ b/.github/workflows/board_generator.yaml
@@ -19,3 +19,4 @@ jobs:
       dart_sdk: stable
       working_directory: packages/board_generator
       coverage_excludes: "**/*.g.dart"
+      min_coverage: 98
diff --git a/packages/board_generator/.gitignore b/packages/board_generator/.gitignore
index 526da1584..4dd1ed845 100644
--- a/packages/board_generator/.gitignore
+++ b/packages/board_generator/.gitignore
@@ -4,4 +4,7 @@
 .dart_tool/
 .packages
 build/
-pubspec.lock
\ No newline at end of file
+pubspec.lock
+
+allWords.json
+board.txt
\ No newline at end of file
diff --git a/packages/board_generator/pubspec.yaml b/packages/board_generator/pubspec.yaml
index 4564e899f..0c00a1b08 100644
--- a/packages/board_generator/pubspec.yaml
+++ b/packages/board_generator/pubspec.yaml
@@ -10,6 +10,10 @@ dependencies:
   built_collection: ^5.1.1
   built_value: ^8.9.1
   characters: ^1.3.0
+  csv: ^6.0.0
+  dart_firebase_admin: ^0.3.0
+  game_domain:
+    path: ../../api/packages/game_domain
 
 dev_dependencies:
   build_runner: ^2.4.8

From 8434fa8fb1ff2cd168b6347da8a5940bf3e73cf5 Mon Sep 17 00:00:00 2001
From: Jaime Sanchez <jaimesanchez8@gmail.com>
Date: Mon, 4 Mar 2024 18:11:12 +0100
Subject: [PATCH 5/9] feat: update board generation

---
 .../board_generator/lib/generate_board.dart   | 23 +++++++++++++++++++
 packages/board_generator/lib/main.dart        | 16 -------------
 2 files changed, 23 insertions(+), 16 deletions(-)
 create mode 100644 packages/board_generator/lib/generate_board.dart
 delete mode 100644 packages/board_generator/lib/main.dart

diff --git a/packages/board_generator/lib/generate_board.dart b/packages/board_generator/lib/generate_board.dart
new file mode 100644
index 000000000..284b2300d
--- /dev/null
+++ b/packages/board_generator/lib/generate_board.dart
@@ -0,0 +1,23 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:board_generator/src/board_generator.dart';
+
+void main(List<String> args) async {
+  final file = File('allWords.json');
+
+  final string = await file.readAsString();
+  final map = jsonDecode(string) as Map<String, dynamic>;
+  final words =
+      (map['words'] as List<dynamic>).map((e) => e as Map<String, dynamic>);
+  final parsedWords = words.map((word) {
+    return word['answer'] as String;
+  }).toList();
+
+  final regex = RegExp(r'^[a-z]+$');
+  final filteredWords = [...parsedWords]..removeWhere(
+      (element) => !regex.hasMatch(element),
+    );
+
+  generateCrossword(filteredWords, 'board.txt');
+}
diff --git a/packages/board_generator/lib/main.dart b/packages/board_generator/lib/main.dart
deleted file mode 100644
index caa759806..000000000
--- a/packages/board_generator/lib/main.dart
+++ /dev/null
@@ -1,16 +0,0 @@
-import 'package:board_generator/board_generator.dart';
-
-/// The list of all words that can be used to generate a crossword.
-final allWords = [
-  'winter',
-  'spring',
-  'summer',
-];
-
-void main(List<String> args) {
-  final iter = generateCrosswords(allWords);
-  final completeCrossword = iter.last;
-
-  // ignore: avoid_print
-  print(completeCrossword);
-}

From 3ac057c3cc5fac4d367056388d190e7c5f9b9ba4 Mon Sep 17 00:00:00 2001
From: Jaime Sanchez <jaimesanchez8@gmail.com>
Date: Mon, 4 Mar 2024 18:11:32 +0100
Subject: [PATCH 6/9] feat: create and upload sections

---
 .../board_generator/lib/create_sections.dart  | 112 ++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 packages/board_generator/lib/create_sections.dart

diff --git a/packages/board_generator/lib/create_sections.dart b/packages/board_generator/lib/create_sections.dart
new file mode 100644
index 000000000..1ecc227da
--- /dev/null
+++ b/packages/board_generator/lib/create_sections.dart
@@ -0,0 +1,112 @@
+// ignore_for_file: avoid_print
+
+import 'dart:io';
+
+import 'package:board_generator/src/crossword_repository.dart';
+import 'package:csv/csv.dart';
+import 'package:dart_firebase_admin/dart_firebase_admin.dart';
+import 'package:dart_firebase_admin/firestore.dart';
+import 'package:game_domain/game_domain.dart';
+
+void main(List<String> args) async {
+  final serviceAccountPath =
+      Platform.environment['GOOGLE_APPLICATION_CREDENTIALS'];
+  if (serviceAccountPath == null) {
+    throw Exception('Service account path not found');
+  }
+
+  final admin = FirebaseAdminApp.initializeApp(
+    'io-crossword-dev',
+    Credential.fromServiceAccount(File(serviceAccountPath)),
+  );
+  final firestore = Firestore(admin);
+  final crosswordRepository = CrosswordRepository(firestore: firestore);
+
+  // Read the file
+  final fileString = File('board.txt').readAsStringSync();
+  final rows = const CsvToListConverter(eol: '\n').convert(fileString);
+
+  // Convert to custom object
+  final words = rows.map((row) {
+    return Word(
+      position: Point(row[0] as int, row[1] as int),
+      answer: row[2] as String,
+      clue: 'The answer is: ${row[2]}',
+      hints: const [],
+      visible: false,
+      axis: row[3] == 'horizontal' ? Axis.horizontal : Axis.vertical,
+      solvedTimestamp: null,
+    );
+  }).toList();
+
+  // Get crossword size
+  final maxX = words
+      .map((e) => e.position.x)
+      .reduce((value, element) => value > element ? value : element);
+  final maxY = words
+      .map((e) => e.position.y)
+      .reduce((value, element) => value > element ? value : element);
+  final minX = words
+      .map((e) => e.position.x)
+      .reduce((value, element) => value < element ? value : element);
+  final minY = words
+      .map((e) => e.position.y)
+      .reduce((value, element) => value < element ? value : element);
+
+  final boardHeight = maxY - minY;
+  final boardWidth = maxX - minX;
+
+  print('Crossword size: $boardWidth x $boardHeight.');
+
+  final sections = <BoardSection>[];
+  const sectionSize = 300;
+
+  var sectionX = minX;
+  while (sectionX < maxX) {
+    var sectionY = minY;
+    while (sectionY < maxY) {
+      final sectionWords = words.where((word) {
+        final isStartInSection = word.position.x >= sectionX &&
+            word.position.x < sectionX + sectionSize &&
+            word.position.y >= sectionY &&
+            word.position.y < sectionY + sectionSize;
+        return isStartInSection;
+      }).toList();
+
+      final borderWords = words.where((word) {
+        final isStartInSection = word.position.x >= sectionX &&
+            word.position.x < sectionX + sectionSize &&
+            word.position.y >= sectionY &&
+            word.position.y < sectionY + sectionSize;
+        final endX = word.axis == Axis.horizontal
+            ? word.position.x + word.answer.length - 1
+            : word.position.x;
+        final endY = word.axis == Axis.vertical
+            ? word.position.y + word.answer.length - 1
+            : word.position.y;
+        final isEndInSection = endX >= sectionX &&
+            endX < sectionX + sectionSize &&
+            endY >= sectionY &&
+            endY < sectionY + sectionSize;
+        return !isStartInSection && isEndInSection;
+      }).toList();
+
+      final section = BoardSection(
+        id: '',
+        position: Point(sectionX, sectionY),
+        size: sectionSize,
+        words: sectionWords,
+        borderWords: borderWords,
+      );
+      sections.add(section);
+
+      sectionY += sectionSize;
+    }
+    sectionX += sectionSize;
+  }
+
+  await crosswordRepository.addSections(sections);
+  // await crosswordRepository.deleteSections();
+
+  print('Added all ${sections.length} section to the database.');
+}

From d0436d7a8f290f67fbd958065112cfae3461d847 Mon Sep 17 00:00:00 2001
From: Jaime Sanchez <jaimesanchez8@gmail.com>
Date: Mon, 4 Mar 2024 18:50:54 +0100
Subject: [PATCH 7/9] docs: update readme

---
 packages/board_generator/README.md            | 41 +++++++++++++++++--
 .../board_generator/lib/create_sections.dart  |  2 +-
 .../board_generator/lib/generate_board.dart   |  4 +-
 .../lib/src/board_generator.dart              |  7 +++-
 4 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/packages/board_generator/README.md b/packages/board_generator/README.md
index 6e0c32707..1ed71ba5f 100644
--- a/packages/board_generator/README.md
+++ b/packages/board_generator/README.md
@@ -8,16 +8,50 @@ Crossword board generator.
 
 ## Usage 💻
 
-**❗ In order to start using Board Generator you must have the [Dart SDK][dart_install_link] installed on your machine.**
+There are two steps in the process to generate a board and have it ready in Firestore:
 
-Run it as a dart program:
+- Board generation
+- Divide board into sections and upload it to Firestore
+
+### Generate the crossword board
+
+Add an `allWords.json` file inside the `assets` folder with all the words that will be used to generate the board with the following structure:
+
+```json
+{
+    "words":[
+        {
+            "answer": "alpine",
+            "definition": "Relative to high mountains"
+        }
+    ]
+}
+```
+
+Then, from the package folder, run:
+
+```sh
+dart lib/generate_board.dart
+```
+
+The board will be created in `assets/board.txt` and updated until all words are placed in it.
+
+### Dividing the board in sections
+
+Once the board is generated, create the sections and upload them to Firestore by running:
 
 ```sh
-dart main.dart
+dart lib/create_sections.dart
 ```
 
+In case you want to update the sections size, do so in the `create_sections.dart` file before creating the sections.
+
+>Note: When creating the sections you will need a service account to upload them to Firestore. Set the `GOOGLE_APPLICATION_CREDENTIALS` environment variable to the path of your service account.
+
 ## Running Tests 🧪
 
+The coverage in this package is not enforced at a 100% due to the nature of testing the algorithm with only a few words.
+
 To run all unit tests:
 
 ```sh
@@ -36,7 +70,6 @@ genhtml coverage/lcov.info -o coverage/
 open coverage/index.html
 ```
 
-[dart_install_link]: https://dart.dev/get-dart
 [license_badge]: https://img.shields.io/badge/license-MIT-blue.svg
 [license_link]: https://opensource.org/licenses/MIT
 [very_good_analysis_badge]: https://img.shields.io/badge/style-very_good_analysis-B22C89.svg
diff --git a/packages/board_generator/lib/create_sections.dart b/packages/board_generator/lib/create_sections.dart
index 1ecc227da..c3e10edab 100644
--- a/packages/board_generator/lib/create_sections.dart
+++ b/packages/board_generator/lib/create_sections.dart
@@ -23,7 +23,7 @@ void main(List<String> args) async {
   final crosswordRepository = CrosswordRepository(firestore: firestore);
 
   // Read the file
-  final fileString = File('board.txt').readAsStringSync();
+  final fileString = File('assets/board.txt').readAsStringSync();
   final rows = const CsvToListConverter(eol: '\n').convert(fileString);
 
   // Convert to custom object
diff --git a/packages/board_generator/lib/generate_board.dart b/packages/board_generator/lib/generate_board.dart
index 284b2300d..37f06f0f6 100644
--- a/packages/board_generator/lib/generate_board.dart
+++ b/packages/board_generator/lib/generate_board.dart
@@ -4,7 +4,7 @@ import 'dart:io';
 import 'package:board_generator/src/board_generator.dart';
 
 void main(List<String> args) async {
-  final file = File('allWords.json');
+  final file = File('assets/allWords.json');
 
   final string = await file.readAsString();
   final map = jsonDecode(string) as Map<String, dynamic>;
@@ -19,5 +19,5 @@ void main(List<String> args) async {
       (element) => !regex.hasMatch(element),
     );
 
-  generateCrossword(filteredWords, 'board.txt');
+  generateCrossword(filteredWords, 'assets/board.txt');
 }
diff --git a/packages/board_generator/lib/src/board_generator.dart b/packages/board_generator/lib/src/board_generator.dart
index cf68e5755..5070694bd 100644
--- a/packages/board_generator/lib/src/board_generator.dart
+++ b/packages/board_generator/lib/src/board_generator.dart
@@ -3,6 +3,7 @@
 import 'dart:io';
 
 import 'package:board_generator/src/models/data_model.dart';
+import 'package:game_domain/game_domain.dart';
 
 /// Generates a crossword.
 Crossword generateCrossword(List<String> wordList, String filePath) {
@@ -37,12 +38,14 @@ Crossword generateCrossword(List<String> wordList, String filePath) {
       final buffer = StringBuffer();
       for (final entry in newAcrossWords.entries) {
         buffer.writeln(
-          '${entry.key.across},${entry.key.down},${entry.value},horizontal',
+          '${entry.key.across},${entry.key.down},${entry.value},'
+          '${Axis.horizontal}',
         );
       }
       for (final entry in newDownWords.entries) {
         buffer.writeln(
-          '${entry.key.across},${entry.key.down},${entry.value},vertical',
+          '${entry.key.across},${entry.key.down},${entry.value},'
+          '${Axis.vertical}',
         );
       }
 

From 65d8e323cd075f1a957c858922a7788006a2fa42 Mon Sep 17 00:00:00 2001
From: Jaime Sanchez <jaimesanchez8@gmail.com>
Date: Mon, 4 Mar 2024 19:03:26 +0100
Subject: [PATCH 8/9] feat: improve readability

---
 .../board_generator/lib/create_sections.dart  | 47 +++++++++++--------
 1 file changed, 27 insertions(+), 20 deletions(-)

diff --git a/packages/board_generator/lib/create_sections.dart b/packages/board_generator/lib/create_sections.dart
index c3e10edab..c1ab0afaf 100644
--- a/packages/board_generator/lib/create_sections.dart
+++ b/packages/board_generator/lib/create_sections.dart
@@ -66,28 +66,14 @@ void main(List<String> args) async {
     var sectionY = minY;
     while (sectionY < maxY) {
       final sectionWords = words.where((word) {
-        final isStartInSection = word.position.x >= sectionX &&
-            word.position.x < sectionX + sectionSize &&
-            word.position.y >= sectionY &&
-            word.position.y < sectionY + sectionSize;
-        return isStartInSection;
+        return word.isStartInSection(sectionX, sectionY, sectionSize);
       }).toList();
 
       final borderWords = words.where((word) {
-        final isStartInSection = word.position.x >= sectionX &&
-            word.position.x < sectionX + sectionSize &&
-            word.position.y >= sectionY &&
-            word.position.y < sectionY + sectionSize;
-        final endX = word.axis == Axis.horizontal
-            ? word.position.x + word.answer.length - 1
-            : word.position.x;
-        final endY = word.axis == Axis.vertical
-            ? word.position.y + word.answer.length - 1
-            : word.position.y;
-        final isEndInSection = endX >= sectionX &&
-            endX < sectionX + sectionSize &&
-            endY >= sectionY &&
-            endY < sectionY + sectionSize;
+        final isStartInSection =
+            word.isStartInSection(sectionX, sectionY, sectionSize);
+        final isEndInSection =
+            word.isEndInSection(sectionX, sectionY, sectionSize);
         return !isStartInSection && isEndInSection;
       }).toList();
 
@@ -106,7 +92,28 @@ void main(List<String> args) async {
   }
 
   await crosswordRepository.addSections(sections);
-  // await crosswordRepository.deleteSections();
 
   print('Added all ${sections.length} section to the database.');
 }
+
+/// An extension on [Word] to check if it is in a section.
+extension SectionBelonging on Word {
+  /// Returns true if the word starting letter is in the section.
+  bool isStartInSection(int sectionX, int sectionY, int sectionSize) {
+    return position.x >= sectionX &&
+        position.x < sectionX + sectionSize &&
+        position.y >= sectionY &&
+        position.y < sectionY + sectionSize;
+  }
+
+  /// Returns true if the word ending letter is in the section.
+  bool isEndInSection(int sectionX, int sectionY, int sectionSize) {
+    final (endX, endY) = axis == Axis.horizontal
+        ? (position.x + answer.length - 1, position.y)
+        : (position.x, position.y + answer.length - 1);
+    return endX >= sectionX &&
+        endX < sectionX + sectionSize &&
+        endY >= sectionY &&
+        endY < sectionY + sectionSize;
+  }
+}

From 2c3812aa3050dd27b1e7505c76814e0ef7d23b4c Mon Sep 17 00:00:00 2001
From: Jaime Sanchez <jaimesanchez8@gmail.com>
Date: Mon, 4 Mar 2024 19:10:04 +0100
Subject: [PATCH 9/9] chore: update min coverage

---
 .github/workflows/board_generator.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/board_generator.yaml b/.github/workflows/board_generator.yaml
index f91970f85..44663e825 100644
--- a/.github/workflows/board_generator.yaml
+++ b/.github/workflows/board_generator.yaml
@@ -19,4 +19,4 @@ jobs:
       dart_sdk: stable
       working_directory: packages/board_generator
       coverage_excludes: "**/*.g.dart"
-      min_coverage: 98
+      min_coverage: 90