import { homedir } from "node:os";
import path from "node:path";
import type { MediaInferenceProvider, MediaSourceProvider } from "@rakazo/adapter-kit";
import { expandHome } from "@rakazo/media/node";
import { EmulatorMediaInferenceProvider } from "./media-emulator.js";
import { EmulatorMediaSourceProvider } from "./media-emulator-source.js";
import { FolderMediaSourceProvider } from "./media-folder-source.js";
import { SidecarMediaInferenceProvider } from "./media-sidecar.js";

export interface MediaConfig {
  /** Media Studio runs: a sidecar is configured or the scripted runtime uses the emulator. */
  enabled: boolean;
  workerUrl: string | null;
  workerToken: string | null;
  profilesDir: string;
  /** `${DATA_DIR}/media`, absolute. Every derived file and sidecar path lives here. */
  mediaRoot: string;
}

export type MediaInferenceKind = "sidecar" | "emulator";

/** Emulators replace the sidecar whenever the scripted runtime is pinned (tests, e2e). */
export function mediaEmulatorEnabled(env: NodeJS.ProcessEnv = process.env): boolean {
  return env.AGENT_RUNTIME === "scripted";
}

export function mediaConfigFromEnv(env: NodeJS.ProcessEnv = process.env): MediaConfig {
  const workerUrl = env.MEDIA_WORKER_URL?.trim() || null;
  const workerToken = env.MEDIA_WORKER_TOKEN?.trim() || null;
  return {
    enabled: mediaEmulatorEnabled(env) || Boolean(workerUrl && workerToken),
    workerUrl,
    workerToken,
    profilesDir: path.resolve(
      expandHome(env.MEDIA_PROFILES_DIR?.trim() || "~/.evoo/media-profiles", homedir()),
    ),
    mediaRoot: path.resolve(env.DATA_DIR ?? "./data", "media"),
  };
}

export function resolveMediaInferenceKind(
  env: NodeJS.ProcessEnv = process.env,
): MediaInferenceKind | null {
  if (mediaEmulatorEnabled(env)) return "emulator";
  const config = mediaConfigFromEnv(env);
  return config.workerUrl && config.workerToken ? "sidecar" : null;
}

/** The configured inference provider, or null when Media Studio is not set up. */
export function createMediaInferenceProvider(
  env: NodeJS.ProcessEnv = process.env,
): MediaInferenceProvider | null {
  const config = mediaConfigFromEnv(env);
  switch (resolveMediaInferenceKind(env)) {
    case "emulator":
      return new EmulatorMediaInferenceProvider({ root: config.mediaRoot });
    case "sidecar":
      return new SidecarMediaInferenceProvider({
        baseUrl: config.workerUrl as string,
        token: config.workerToken as string,
      });
    default:
      return null;
  }
}

/** Emulator clips are cached inside the media root so inference can read them. */
export function emulatorFixturesDir(env: NodeJS.ProcessEnv = process.env): string {
  return path.join(mediaConfigFromEnv(env).mediaRoot, "emulator-library");
}

/**
 * Server-side source adapter for a persisted MediaSource kind. Client-pushed
 * kinds (apple_photos, ios_library) have no server adapter.
 */
export function createMediaSourceProvider(
  kind: string,
  env: NodeJS.ProcessEnv = process.env,
): MediaSourceProvider {
  switch (kind) {
    case "folder":
      return new FolderMediaSourceProvider();
    case "emulator":
      if (!mediaEmulatorEnabled(env)) break;
      return new EmulatorMediaSourceProvider({ fixturesDir: emulatorFixturesDir(env) });
    default:
      break;
  }
  throw new Error(`No server-side media source for "${kind}". Use folder.`);
}