feat(core): add Electron runtime, services, and app composition

src/main/runtime/mpv-osd-log.ts

@@ -0,0 +1,70 @@
+import type { MpvRuntimeClientLike } from '../../core/services/mpv';
+
+export function createAppendToMpvLogHandler(deps: {
+  logPath: string;
+  dirname: (targetPath: string) => string;
+  mkdir: (targetPath: string, options: { recursive: boolean }) => Promise<void>;
+  appendFile: (targetPath: string, data: string, options: { encoding: 'utf8' }) => Promise<void>;
+  now: () => Date;
+}) {
+  const pendingLines: string[] = [];
+  let drainPromise: Promise<void> | null = null;
+
+  const drainPendingLines = async (): Promise<void> => {
+    while (pendingLines.length > 0) {
+      const chunk = pendingLines.splice(0, pendingLines.length).join('');
+      try {
+        await deps.mkdir(deps.dirname(deps.logPath), { recursive: true });
+        await deps.appendFile(deps.logPath, chunk, { encoding: 'utf8' });
+      } catch {
+        // best-effort logging
+      }
+    }
+  };
+
+  const scheduleDrain = (): Promise<void> => {
+    if (drainPromise) return drainPromise;
+    drainPromise = (async () => {
+      try {
+        await drainPendingLines();
+      } finally {
+        drainPromise = null;
+      }
+    })();
+    return drainPromise;
+  };
+
+  const appendToMpvLog = (message: string): void => {
+    pendingLines.push(`[${deps.now().toISOString()}] ${message}\n`);
+    void scheduleDrain();
+  };
+
+  const flushMpvLog = async (): Promise<void> => {
+    while (pendingLines.length > 0 || drainPromise) {
+      await scheduleDrain();
+    }
+  };
+
+  return {
+    appendToMpvLog,
+    flushMpvLog,
+  };
+}
+
+export function createShowMpvOsdHandler(deps: {
+  appendToMpvLog: (message: string) => void;
+  showMpvOsdRuntime: (
+    mpvClient: MpvRuntimeClientLike | null,
+    text: string,
+    fallbackLog: (line: string) => void,
+  ) => void;
+  getMpvClient: () => MpvRuntimeClientLike | null;
+  logInfo: (line: string) => void;
+}) {
+  return (text: string): void => {
+    deps.appendToMpvLog(`[OSD] ${text}`);
+    deps.showMpvOsdRuntime(deps.getMpvClient(), text, (line) => {
+      deps.logInfo(line);
+    });
+  };
+}