1 files changed, 184 insertions, 24 deletions

diff --git a/src/data/language.js b/src/data/language.js
index 09466907..3fc14da7 100644
--- a/src/data/language.js
+++ b/src/data/language.js
@@ -1,39 +1,199 @@
+import EventEmitter from 'node:events';
 import {readFile} from 'node:fs/promises';
+import path from 'node:path';
+import {fileURLToPath} from 'node:url';
 
-// It stands for "HTML Entities", apparently. Cursed.
-import he from 'he';
+import chokidar from 'chokidar';
+import he from 'he'; // It stands for "HTML Entities", apparently. Cursed.
+import yaml from 'js-yaml';
 
 import T from '#things';
+import {colors, logWarn} from '#cli';
 
-export async function processLanguageFile(file) {
-  const contents = await readFile(file, 'utf-8');
-  const json = JSON.parse(contents);
+import {
+  annotateError,
+  annotateErrorWithFile,
+  showAggregate,
+  withAggregate,
+} from '#sugar';
+
+const {Language} = T;
+
+export const DEFAULT_STRINGS_FILE = 'strings-default.yaml';
+
+export const internalDefaultStringsFile =
+  path.resolve(
+    path.dirname(fileURLToPath(import.meta.url)),
+    '../',
+    DEFAULT_STRINGS_FILE);
+
+export function processLanguageSpec(spec, {existingCode = null} = {}) {
+  const {
+    'meta.languageCode': code,
+    'meta.languageName': name,
+
+    'meta.languageIntlCode': intlCode = null,
+    'meta.hidden': hidden = false,
+
+    ...strings
+  } = spec;
+
+  withAggregate({message: `Errors validating language spec`}, ({push}) => {
+    if (!code) {
+      push(new Error(`Missing language code`));
+    }
+
+    if (!name) {
+      push(new Error(`Missing language name`));
+    }
+
+    if (code && existingCode && code !== existingCode) {
+      push(new Error(`Language code (${code}) doesn't match previous value\n(You'll have to reload hsmusic to load this)`));
+    }
+  });
+
+  return {code, intlCode, name, hidden, strings};
+}
 
-  const code = json['meta.languageCode'];
-  if (!code) {
-    throw new Error(`Missing language code (file: ${file})`);
+function flattenLanguageSpec(spec) {
+  const recursive = (keyPath, value) =>
+    (typeof value === 'object'
+      ? Object.assign({}, ...
+          Object.entries(value)
+            .map(([key, value]) =>
+              (key === '_'
+                ? {[keyPath]: value}
+                : recursive(
+                    (keyPath ? `${keyPath}.${key}` : key),
+                    value))))
+      : {[keyPath]: value});
+
+  return recursive('', spec);
+}
+
+async function processLanguageSpecFromFile(file, processLanguageSpecOpts) {
+  let contents;
+
+  try {
+    contents = await readFile(file, 'utf-8');
+  } catch (caughtError) {
+    throw annotateError(
+      new Error(`Failed to read language file`, {cause: caughtError}),
+      error => annotateErrorWithFile(error, file));
   }
-  delete json['meta.languageCode'];
 
-  const intlCode = json['meta.languageIntlCode'] ?? null;
-  delete json['meta.languageIntlCode'];
+  let rawSpec;
+  let parseLanguage;
 
-  const name = json['meta.languageName'];
-  if (!name) {
-    throw new Error(`Missing language name (${code})`);
+  try {
+    if (path.extname(file) === '.yaml') {
+      parseLanguage = 'YAML';
+      rawSpec = yaml.load(contents);
+    } else {
+      parseLanguage = 'JSON';
+      rawSpec = JSON.parse(contents);
+    }
+  } catch (caughtError) {
+    throw annotateError(
+      new Error(`Failed to parse language file as valid ${parseLanguage}`, {cause: caughtError}),
+      error => annotateErrorWithFile(error, file));
   }
-  delete json['meta.languageName'];
 
-  const hidden = json['meta.hidden'] ?? false;
-  delete json['meta.hidden'];
+  const flattenedSpec = flattenLanguageSpec(rawSpec);
 
-  const language = new T.Language();
-  language.code = code;
-  language.intlCode = intlCode;
-  language.name = name;
-  language.hidden = hidden;
-  language.escapeHTML = (string) =>
+  try {
+    return processLanguageSpec(flattenedSpec, processLanguageSpecOpts);
+  } catch (caughtError) {
+    throw annotateErrorWithFile(caughtError, file);
+  }
+}
+
+export function initializeLanguageObject() {
+  const language = new Language();
+
+  language.escapeHTML = string =>
     he.encode(string, {useNamedReferences: true});
-  language.strings = json;
+
   return language;
 }
+
+export async function processLanguageFile(file) {
+  const language = initializeLanguageObject();
+  const properties = await processLanguageSpecFromFile(file);
+  return Object.assign(language, properties);
+}
+
+export function watchLanguageFile(file, {
+  logging = true,
+} = {}) {
+  const basename = path.basename(file);
+
+  const events = new EventEmitter();
+  const language = initializeLanguageObject();
+
+  let emittedReady = false;
+  let successfullyAppliedLanguage = false;
+
+  Object.assign(events, {language, close});
+
+  const watcher = chokidar.watch(file);
+  watcher.on('change', () => handleFileUpdated());
+
+  setImmediate(handleFileUpdated);
+
+  return events;
+
+  async function close() {
+    return watcher.close();
+  }
+
+  function checkReadyConditions() {
+    if (emittedReady) return;
+    if (!successfullyAppliedLanguage) return;
+
+    events.emit('ready');
+    emittedReady = true;
+  }
+
+  async function handleFileUpdated() {
+    let properties;
+
+    try {
+      properties = await processLanguageSpecFromFile(file, {
+        existingCode:
+          (successfullyAppliedLanguage
+            ? language.code
+            : null),
+      });
+    } catch (error) {
+      events.emit('error', error);
+
+      if (logging) {
+        const label =
+          (successfullyAppliedLanguage
+            ? `${language.name} (${language.code})`
+            : basename);
+
+        if (successfullyAppliedLanguage) {
+          logWarn`Failed to load language ${label} - using existing version`;
+        } else {
+          logWarn`Failed to load language ${label} - no prior version loaded`;
+        }
+        showAggregate(error, {showTraces: false});
+      }
+
+      return;
+    }
+
+    Object.assign(language, properties);
+    successfullyAppliedLanguage = true;
+
+    if (logging && emittedReady) {
+      const timestamp = new Date().toLocaleString('en-US', {timeStyle: 'medium'});
+      console.log(colors.green(`[${timestamp}] Updated language ${language.name} (${language.code})`));
+    }
+
+    events.emit('update');
+    checkReadyConditions();
+  }
+}