From 792279b7bf154ecf03aebc5f91c7d146e6f8a128 Mon Sep 17 00:00:00 2001
From: Diogo Resende <dresende@thinkdigital.pt>
Date: Mon, 15 Apr 2013 22:25:43 +0100
Subject: [PATCH] Adds support for descending ordering using "-property" (#115)

---
 lib/ChainFind.js                  |  5 +++-
 lib/Drivers/DML/mysql.js          |  4 ++-
 lib/Drivers/DML/postgres.js       |  4 ++-
 lib/Drivers/DML/postgresaxomic.js |  4 ++-
 lib/Drivers/DML/sqlite.js         |  4 ++-
 lib/Model.js                      |  5 ++++
 lib/Utilities.js                  | 46 +++++++++++++++++++++++++++++++
 7 files changed, 67 insertions(+), 5 deletions(-)
 create mode 100644 lib/Utilities.js

diff --git a/lib/ChainFind.js b/lib/ChainFind.js
index 41c6479a..f682df37 100644
--- a/lib/ChainFind.js
+++ b/lib/ChainFind.js
@@ -25,7 +25,10 @@ function ChainFind(opts) {
 			return this;
 		},
 		order: function (property, order) {
-			opts.order = [ property, order ];
+			if (!Array.isArray(opts.order)) {
+				opts.order = [];
+			}
+			opts.order.push([ property, (order && order.toUpperCase() == "Z" ? "Z" : "A") ]);
 			return this;
 		},
 		count: function (cb) {
diff --git a/lib/Drivers/DML/mysql.js b/lib/Drivers/DML/mysql.js
index ed300039..ecc8843e 100644
--- a/lib/Drivers/DML/mysql.js
+++ b/lib/Drivers/DML/mysql.js
@@ -99,7 +99,9 @@ Driver.prototype.find = function (fields, table, conditions, opts, cb) {
 		q.limit('18446744073709551615');
 	}
 	if (opts.order) {
-		q.order(opts.order[0], opts.order[1]);
+		for (var i = 0; i < opts.order.length; i++) {
+			q.order(opts.order[i][0], opts.order[i][1]);
+		}
 	}
 
 	if (opts.merge) {
diff --git a/lib/Drivers/DML/postgres.js b/lib/Drivers/DML/postgres.js
index 067a9bdc..f9a485d7 100644
--- a/lib/Drivers/DML/postgres.js
+++ b/lib/Drivers/DML/postgres.js
@@ -74,7 +74,9 @@ Driver.prototype.find = function (fields, table, conditions, opts, cb) {
 		q.limit(opts.limit);
 	}
 	if (opts.order) {
-		q.order(opts.order[0], opts.order[1]);
+		for (var i = 0; i < opts.order.length; i++) {
+			q.order(opts.order[i][0], opts.order[i][1]);
+		}
 	}
 
 	if (opts.merge) {
diff --git a/lib/Drivers/DML/postgresaxomic.js b/lib/Drivers/DML/postgresaxomic.js
index 4a7a983a..97ed16db 100644
--- a/lib/Drivers/DML/postgresaxomic.js
+++ b/lib/Drivers/DML/postgresaxomic.js
@@ -73,7 +73,9 @@ Driver.prototype.find = function (fields, table, conditions, opts, cb) {
 		q.limit(opts.limit);
 	}
 	if (opts.order) {
-		q.order(opts.order[0], opts.order[1]);
+		for (var i = 0; i < opts.order.length; i++) {
+			q.order(opts.order[i][0], opts.order[i][1]);
+		}
 	}
 
 	if (opts.merge) {
diff --git a/lib/Drivers/DML/sqlite.js b/lib/Drivers/DML/sqlite.js
index ab76794f..e1ef7b9b 100644
--- a/lib/Drivers/DML/sqlite.js
+++ b/lib/Drivers/DML/sqlite.js
@@ -74,7 +74,9 @@ Driver.prototype.find = function (fields, table, conditions, opts, cb) {
 		q.limit('9223372036854775807');
 	}
 	if (opts.order) {
-		q.order(opts.order[0], opts.order[1]);
+		for (var i = 0; i < opts.order.length; i++) {
+			q.order(opts.order[i][0], opts.order[i][1]);
+		}
 	}
 
 	if (opts.merge) {
diff --git a/lib/Model.js b/lib/Model.js
index e7657dca..99a6bd39 100644
--- a/lib/Model.js
+++ b/lib/Model.js
@@ -4,6 +4,7 @@ var OneAssociation  = require("./Associations/One");
 var ManyAssociation = require("./Associations/Many");
 var ChainFind       = require("./ChainFind");
 var LazyLoad        = require("./LazyLoad");
+var Utilities       = require("./Utilities");
 
 exports.Model = Model;
 
@@ -224,6 +225,10 @@ function Model(opts) {
 			options.cache = opts.cache;
 		}
 
+		if (order) {
+			order = Utilities.standardizeOrder(order);
+		}
+
 		var chain = new ChainFind({
 			only         : options.only || model_fields,
 			id           : opts.id,
diff --git a/lib/Utilities.js b/lib/Utilities.js
new file mode 100644
index 00000000..a5afe76a
--- /dev/null
+++ b/lib/Utilities.js
@@ -0,0 +1,46 @@
+/**
+ * Order should be a String (with the property name assumed ascending)
+ * or an Array or property String names.
+ *
+ * Examples:
+ *
+ * 1. 'property1' (ORDER BY property1 ASC)
+ * 2. '-property1' (ORDER BY property1 DESC)
+ * 3. [ 'property1' ] (ORDER BY property1 ASC)
+ * 4. [ '-property1' ] (ORDER BY property1 DESC)
+ * 5. [ 'property1', 'A' ] (ORDER BY property1 ASC)
+ * 6. [ 'property1', 'Z' ] (ORDER BY property1 DESC)
+ * 7. [ '-property1', 'A' ] (ORDER BY property1 ASC)
+ * 8. [ 'property1', 'property2' ] (ORDER BY property1 ASC, property2 ASC)
+ * 9. [ 'property1', '-property2' ] (ORDER BY property1 ASC, property2 DESC)
+ * ...
+ */
+
+exports.standardizeOrder = function (order) {
+	if (typeof order == "string") {
+		if (order[0] == "-") {
+			return [ [ order.substr(1), "Z" ] ];
+		}
+		return [ [ order, "A" ] ];
+	}
+
+	var new_order = [], minus;
+
+	for (var i = 0; i < order.length; i++) {
+		minus = (order[i][0] == "-");
+
+		if (i < order.length - 1 && [ "A", "Z" ].indexOf(order[i + 1].toUpperCase()) >= 0) {
+			new_order.push([
+				(minus ? order[i].substr(1) : order[i]),
+				order[i + 1]
+			]);
+			i += 1;
+		} else if (minus) {
+			new_order.push([ order[i].substr(1), "Z" ]);
+		} else {
+			new_order.push([ order[i], "A" ]);
+		}
+	}
+
+	return new_order;
+};