1 files changed, 221 insertions, 0 deletions
diff --git a/src/content-cache.js b/src/content-cache.js
new file mode 100644
index 00000000..795860d6
--- /dev/null
+++ b/src/content-cache.js
@@ -0,0 +1,221 @@
+import {getArgsForRelationsAndData} from './content-function.js';
+import {quickLoadAllFromYAML} from './data/yaml.js';
+import {compareArrays} from './util/sugar.js';
+
+export class TupleMap {
+  #store = [undefined, new WeakMap(), new Map()];
+
+  #lifetime(value) {
+    if (
+      typeof value === 'object' && value !== null ||
+      typeof value === 'function'
+    ) {
+      return 'weak';
+    } else {
+      return 'strong';
+    }
+  }
+
+  #getSubstoreShallow(value, store) {
+    const map = store[this.#lifetime(value) === 'weak' ? 1 : 2];
+    if (map.has(value)) {
+      return map.get(value);
+    } else {
+      const substore = [undefined, new WeakMap(), new Map()];
+      map.set(value, substore);
+      return substore;
+    }
+  }
+
+  #getSubstoreDeep(tuple, store = this.#store) {
+    if (tuple.length === 0) {
+      return store;
+    } else {
+      const [first, ...rest] = tuple;
+      return this.#getSubstoreDeep(rest, this.#getSubstoreShallow(first, store));
+    }
+  }
+
+  get(tuple) {
+    const store = this.#getSubstoreDeep(tuple);
+    return store[0];
+  }
+
+  set(tuple, value) {
+    const store = this.#getSubstoreDeep(tuple);
+    store[0] = value;
+    return value;
+  }
+}
+
+export default class ContentCache {
+  #contentFunctions = {};
+  #extraDependencies = {};
+
+  #contentDependenciesTree = {};
+  #desiredContentFunctionCalls = [];
+
+  #cachedRelationsLayouts = new TupleMap();
+  #cachedRelationsSlots = new TupleMap();
+
+  #relationIdentifier = Symbol();
+
+  wikiData = {};
+
+  constructor() {}
+
+  desireContentFunction(functionName, args, levelOfDesire) {
+    this.#desiredContentFunctionCalls.push({functionName, args, levelOfDesire});
+  }
+
+  #getPotentiallyDirectlyDependantContentFunctions(functionName) {
+    const direct =
+      Object.entries(this.#contentDependenciesTree)
+        .filter(([name, dependencies]) => dependencies.has(functionName))
+        .map(([name]) => name);
+
+    return new Set(direct);
+  }
+
+  #getPotentiallyDependantContentFunctions(functionName) {
+    const direct = this.#getPotentiallyDirectlyDependantContentFunctions(functionName);
+    const indirect =
+      Array.from(direct)
+        .flatMap(name => Array.from(this.#getPotentiallyDirectlyDependantContentFunctions(name)));
+
+    return new Set([...direct, ...indirect]);
+  }
+
+  #prepareRelations(functionName, args) {
+    const tuple = [functionName, ...args];
+    if (
+      this.#cachedRelationsLayouts.get(tuple) &&
+      this.#cachedRelationsSlots.get(tuple)
+    ) {
+      return;
+    }
+
+    const contentFunction = this.#contentFunctions[functionName];
+    const argsForRelations =
+      getArgsForRelationsAndData(contentFunction, this.wikiData, ...args);
+
+    const listedDependencies = new Set(contentFunction.contentDependencies);
+
+    // Note: "slots" here is a completely separate concept from HTML template
+    // slots, which are handled completely within the content function. Here,
+    // relation slots are just references to a position within the relations
+    // layout that are referred to by a symbol - when the relation is ready,
+    // its result will be "slotted" into the layout.
+    const relationSlots = {};
+
+    const relationSymbolMessage = (() => {
+      let num = 1;
+      return name => `#${num++} ${name}`;
+    })();
+
+    const relationFunction = (name, ...args) => {
+      if (!listedDependencies.has(name)) {
+        throw new Error(`Called relation('${name}') but ${functionName} doesn't list that dependency`);
+      }
+
+      const relationSymbol = Symbol(relationSymbolMessage(name));
+      relationSlots[relationSymbol] = {name, args};
+      return {[this.#relationIdentifier]: relationSymbol};
+    };
+
+    const relationsLayout =
+      contentFunction.relations(relationFunction, ...argsForRelations);
+
+    this.#cachedRelationsLayouts.set([functionName, ...args], relationsLayout);
+    this.#cachedRelationsSlots.set([functionName, ...args], relationSlots);
+  }
+
+  getRelationsLayout(functionName, args) {
+    this.#prepareRelations(functionName, args);
+    return this.#cachedRelationsLayouts.get([functionName, ...args]);
+  }
+
+  getRelationsSlots(functionName, args) {
+    this.#prepareRelations(functionName, args);
+    return this.#cachedRelationsSlots.get([functionName, ...args]);
+  }
+
+  scoreContentFunctionDesirability(scoreFunctionName, scoreArgs) {
+    const potentiallyDependantNames = this.#getPotentiallyDependantContentFunctions(scoreFunctionName);
+
+    let score = 0;
+
+    const recursive = (namesAndArgs, levelOfDesire) => {
+      for (const {name, args} of namesAndArgs) {
+        if (name === scoreFunctionName) {
+          if (compareArrays(args, scoreArgs)) {
+            score += levelOfDesire;
+          }
+        } else if (!potentiallyDependantNames.has(name)) {
+          continue;
+        }
+        const slots = this.getRelationsSlots(name, args);
+        const symbols = Object.getOwnPropertySymbols(slots);
+        recursive(symbols.map(symbol => slots[symbol]), levelOfDesire);
+      }
+    };
+
+    for (const {functionName: name, args, levelOfDesire} of this.#desiredContentFunctionCalls) {
+      recursive([{name, args}], levelOfDesire);
+    }
+
+    return score;
+  }
+
+  /*
+  evaluateContentFunction(functionName, args) {
+  }
+  */
+
+  updateContentDependency(functionName, contentFunction) {
+    this.#contentFunctions[functionName] =
+      contentFunction;
+
+    this.#contentDependenciesTree[functionName] =
+      contentFunction.contentDependencies;
+  }
+
+  updateExtraDependency(dependencyName, value) {
+    this.#extraDependencies[dependencyName] = value;
+  }
+
+  connectContentDependenciesWatcher(watcher) {
+    watcher.on('update', functionName => {
+      this.updateContentDependency(
+        functionName,
+        watcher.contentDependencies[functionName]);
+    });
+  }
+}
+
+(async function() {
+  const {watchContentDependencies} = await import('./content/dependencies/index.js');
+  const contentDependenciesWatcher = await watchContentDependencies();
+
+  const cache = new ContentCache();
+  cache.connectContentDependenciesWatcher(contentDependenciesWatcher);
+
+  await new Promise(resolve => contentDependenciesWatcher.once('ready', resolve));
+
+  cache.wikiData = await quickLoadAllFromYAML(process.env.HSMUSIC_DATA);
+
+  for (const album of cache.wikiData.albumData) {
+    cache.desireContentFunction('generateAlbumInfoPage', [album], 10000);
+    cache.desireContentFunction('generateAlbumGalleryPage', [album], 10000);
+    for (const track of album.tracks) {
+      cache.desireContentFunction('generateTrackInfoPage', [track], 1);
+    }
+  }
+
+  for (const album of cache.wikiData.albumData) {
+    console.log(album, cache.scoreContentFunctionDesirability('linkAlbum', [album]));
+  }
+  // console.log(cache.scoreContentFunctionDesirability('linkAlbum', [cache.wikiData.albumData[0]]));
+  // console.log(cache.scoreContentFunctionDesirability('linkAlbum', [cache.wikiData.albumData[1]]));
+  // console.log(cache.scoreContentFunctionDesirability('linkAlbum', [cache.wikiData.albumData[2]]));
+})().catch(err => console.error(err));