Add CommandContext translator to interface adaptor.

We might want to make the translation function async
i'm not sure yet, it depends if we need it once integration
into draupnir progresses a little more.

src/MatrixInterfaceAdaptor/AdaptorToCommandContextTranslator.ts

@@ -0,0 +1,75 @@
+// SPDX-FileCopyrightText: 2024 Gnuxie <Gnuxie@protonmail.com>
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// SPDX-FileAttributionText: <text>
+// This modified file incorporates work from @the-draupnir-project/interface-manager
+// https://github.com/the-draupnir-project/interface-manager
+// </text>
+
+import { CommandDescription } from "../Command";
+
+/**
+ * This is used to add clue code to take what is essentially a god context into a more specific
+ * attenuated one that can be unit tested easily.
+ * So basically, rather than giving a command the entirity of Draupnir, we can
+ * give it juts the capability to ban a user. Which simplifies test setup.
+ */
+export type AdaptorToCommandContextTranslationFunction<
+  AdaptorContext,
+  CommandContext,
+> = (adaptorContext: AdaptorContext) => CommandContext;
+
+export interface AdaptorToCommandContextTranslator<AdaptorContext> {
+  translateContext<CommandContext>(
+    commandDescription: CommandDescription<CommandContext>,
+    adaptorContext: AdaptorContext
+  ): CommandContext;
+  registerTranslation<CommandContext>(
+    commandDescription: CommandDescription<CommandContext>,
+    translationFunction: AdaptorToCommandContextTranslationFunction<
+      AdaptorContext,
+      CommandContext
+    >
+  ): AdaptorToCommandContextTranslator<AdaptorContext>;
+}
+
+export class StandardAdaptorToCommandContextTranslator<AdaptorContext>
+  implements AdaptorToCommandContextTranslator<AdaptorContext>
+{
+  private readonly translators = new Map<
+    CommandDescription,
+    AdaptorToCommandContextTranslationFunction<AdaptorContext, unknown>
+  >();
+  translateContext<CommandContext>(
+    commandDescription: CommandDescription<CommandContext>,
+    adaptorContext: AdaptorContext
+  ): CommandContext {
+    const entry = this.translators.get(
+      commandDescription as CommandDescription
+    );
+    if (entry === undefined) {
+      return adaptorContext as unknown as CommandContext;
+    } else {
+      return entry(adaptorContext) as CommandContext;
+    }
+  }
+  registerTranslation<CommandContext>(
+    commandDescription: CommandDescription<CommandContext>,
+    translationFunction: AdaptorToCommandContextTranslationFunction<
+      AdaptorContext,
+      CommandContext
+    >
+  ): AdaptorToCommandContextTranslator<AdaptorContext> {
+    if (this.translators.has(commandDescription as CommandDescription)) {
+      throw new TypeError(
+        `There is already a translation function registered for the command ${commandDescription.summary}`
+      );
+    }
+    this.translators.set(
+      commandDescription as CommandDescription,
+      translationFunction
+    );
+    return this;
+  }
+}

src/MatrixInterfaceAdaptor/MatrixInterfaceAdaptor.ts

@@ -15,6 +15,7 @@ import {
 } from "../Command";
 import { MatrixRendererDescription } from "./MatrixRendererDescription";
 import { DocumentNode } from "../DeadDocument";
+import { AdaptorToCommandContextTranslator } from "./AdaptorToCommandContextTranslator";
 
 export interface MatrixInterfaceAdaptor<MatrixEventContext> {
   invoke<CommandResult>(
@@ -69,6 +70,7 @@ export class StandardMatrixInterfaceAdaptor<AdaptorContext, MatrixEventContext>
   >();
   public constructor(
     private readonly adaptorContext: AdaptorContext,
+    private readonly adaptorToCommandContextTranslator: AdaptorToCommandContextTranslator<AdaptorContext>,
     private readonly defaultRenderer: MatrixInterfaceDefaultRenderer<
       AdaptorContext,
       MatrixEventContext
@@ -91,8 +93,13 @@ export class StandardMatrixInterfaceAdaptor<AdaptorContext, MatrixEventContext>
     const renderer = this.findRendererForCommandDescription(
       command.description
     );
+    const commandContext =
+      this.adaptorToCommandContextTranslator.translateContext(
+        command.description,
+        this.adaptorContext
+      );
     const commandResult = await command.description.executor(
-      this.adaptorContext,
+      commandContext,
       command.keywords,
       ...command.immediateArguments,
       ...(command.rest ?? [])

src/MatrixInterfaceAdaptor/index.ts

@@ -2,6 +2,7 @@
 //
 // SPDX-License-Identifier: Apache-2.0
 
+export * from "./AdaptorToCommandContextTranslator";
 export * from "./MatrixInterfaceAdaptor";
 export * from "./MatrixInterfaceCommandDispatcher";
 export * from "./MatrixRendererDescription";