// Project store. Manifests live EITHER as JSON files under public/projects/<id>/project.json (default)
// OR in a Postgres `projects` table when DATABASE_URL is set (see db.mjs). Media files (assets/audio)
// always live on disk under public/projects/<id>/ for now (object storage is a later step), so its
// folder is still created in both modes. All manifest ops are async (Postgres is async-only).
//
//   public/projects/<id>/assets/   ← imported B-roll / face-cam clips (this project only)
//   public/projects/<id>/audio/    ← base voiceover/source audio (import projects)
import fs from "node:fs";
import path from "node:path";
import { execFileSync } from "node:child_process";
import { fileURLToPath } from "node:url";
import { pgEnabled, pgRead, pgWrite, pgExists, pgList, pgRemove } from "./db.mjs";
import { storageEnabled, deletePrefix, copyPrefix } from "./storage.mjs";

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const ROOT = path.resolve(__dirname, "..");
export const PUBLIC = path.join(ROOT, "public");
const PROJECTS = path.join(PUBLIC, "projects");
fs.mkdirSync(PROJECTS, { recursive: true });

const ID_RE = /^p_[a-z0-9]+$/i;
export const validId = (id) => ID_RE.test(String(id || ""));
const dir = (id) => path.join(PROJECTS, id);
const manifestPath = (id) => path.join(dir(id), "project.json");
const rid = (p) => p + Date.now().toString(36) + Math.random().toString(36).slice(2, 6);
export const newId = () => rid("p_");

// the asset/audio folders live on disk in BOTH modes (media isn't in Postgres)
function ensureDirs(id) {
  fs.mkdirSync(path.join(dir(id), "assets"), { recursive: true });
  fs.mkdirSync(path.join(dir(id), "audio"), { recursive: true });
}

const PG = () => pgEnabled(); // chosen per-call so .env load order never matters

// serialize manifest writes per project id so read-modify-write ops can't interleave within the
// process — fixes the autosave-vs-asset-append clobber and the ownerless-claim race. (Single-process
// only; horizontal scaling later needs DB-level compare-and-set.)
const _tail = new Map();
function withLock(id, fn) {
  const run = (_tail.get(id) || Promise.resolve()).then(fn, fn);
  const guarded = run.catch(() => {});
  _tail.set(id, guarded);
  guarded.then(() => { if (_tail.get(id) === guarded) _tail.delete(id); });
  return run;
}

// announce the active backend once, and warn if on-disk projects would be stranded by PG mode
try {
  const onDisk = fs.existsSync(PROJECTS) ? fs.readdirSync(PROJECTS).filter((d) => validId(d) && fs.existsSync(manifestPath(d))).length : 0;
  console.log(`[projects] storage backend: ${PG() ? "postgres (DATABASE_URL set)" : "files (public/projects)"}`);
  if (PG() && onDisk > 0) console.warn(`[projects] WARNING: ${onDisk} project(s) exist as files on disk but Postgres mode is active — they will NOT appear until migrated into the DB.`);
} catch { /* ignore */ }

// --- backend-agnostic manifest primitives (async) ---

export async function exists(id) {
  if (!validId(id)) return false;
  return PG() ? pgExists(id) : fs.existsSync(manifestPath(id));
}

export async function read(id) {
  if (!validId(id)) return null;
  if (PG()) return pgRead(id);
  if (!fs.existsSync(manifestPath(id))) return null;
  try { return JSON.parse(fs.readFileSync(manifestPath(id), "utf8")); } catch { return null; }
}

export async function write(m) {
  ensureDirs(m.id);
  m.updatedAt = new Date().toISOString();
  if (PG()) return pgWrite(m);
  fs.writeFileSync(manifestPath(m.id), JSON.stringify(m, null, 2));
  return m;
}

const DEFAULTS = {
  name: "Untitled project", source: "script", audioSrc: "",
  words: [], motion: [], videos: [], tracks: [], assets: [], sections: [],
  designStyle: "obsidian-orbit", captionStyle: "tiktok-pop", captionsOn: true, lang: "en",
};

// only persist known editor fields with the RIGHT type (ignore client junk / playhead / history,
// and reject e.g. motion:"hacked" that would crash the loader). ownerId is server-controlled (not here).
const FIELDS = Object.keys(DEFAULTS);
const typeOk = (k, v) => Array.isArray(DEFAULTS[k]) ? Array.isArray(v) : typeof v === typeof DEFAULTS[k];
const pick = (o) => { const out = {}; for (const k of FIELDS) if (k in o && typeOk(k, o[k])) out[k] = o[k]; return out; };

// ownership: a project belongs to a user (manifest.ownerId). Legacy projects with no ownerId are
// claimable by anyone — the first save stamps the owner — so existing local projects keep working.
export async function owns(id, userId) {
  const m = await read(id);
  return !!m && (m.ownerId == null || m.ownerId === userId);
}

export async function create(input = {}, ownerId = null) {
  const id = input.id && validId(input.id) ? input.id : newId();
  return withLock(id, async () => {
    // never overwrite an existing project via create() — a client-supplied id for a project that
    // already exists would otherwise clobber/hijack another tenant's manifest (the demo-seed path
    // guards with exists() before calling create, so it never reaches here). Returns null → 409.
    if (await exists(id)) return null;
    ensureDirs(id);
    const now = new Date().toISOString();
    const m = { id, ...DEFAULTS, ...pick(input), ownerId, createdAt: now, updatedAt: now };
    return write(m);
  });
}

export async function save(id, patch, userId = null) {
  return withLock(id, async () => {
    const m = await read(id);
    if (!m) return null;
    if (m.ownerId != null && userId != null && m.ownerId !== userId) return null; // not the owner
    Object.assign(m, pick(patch || {}));
    if (m.ownerId == null && userId != null) m.ownerId = userId; // claim a legacy project on first save
    return write(m);
  });
}

const summarize = (m) => ({ id: m.id, name: m.name, source: m.source, createdAt: m.createdAt, updatedAt: m.updatedAt, words: (m.words || []).length, assets: (m.assets || []).length });

export async function list(userId = null) {
  let manifests;
  if (PG()) {
    manifests = await pgList(userId);
  } else {
    manifests = !fs.existsSync(PROJECTS) ? [] : fs.readdirSync(PROJECTS)
      .filter((d) => validId(d) && fs.existsSync(manifestPath(d))) // ignore stray/non-project dirs (parity with PG)
      .map((d) => { try { return JSON.parse(fs.readFileSync(manifestPath(d), "utf8")); } catch { return null; } })
      .filter((m) => m && (userId == null || m.ownerId == null || m.ownerId === userId));
  }
  return manifests.map(summarize).sort((a, b) => String(b.updatedAt || "").localeCompare(String(a.updatedAt || "")));
}

export async function remove(id, userId = null) {
  return withLock(id, async () => {
    if (!(await exists(id))) return false;
    if (userId != null && !(await owns(id, userId))) return false; // only the owner can delete
    if (PG()) await pgRemove(id);
    if (storageEnabled()) await deletePrefix(`projects/${id}/`); // delete this project's objects from the bucket
    fs.rmSync(dir(id), { recursive: true, force: true }); // also clears any on-disk asset/audio files
    return true;
  });
}

// duplicate a project into a brand-new one owned by `userId`: copies the manifest AND all media bytes
// (assets/ + audio/, on disk and/or in the bucket), and remaps every project-scoped path so the copy
// is fully self-contained — editing/deleting the clone never touches the original's files.
export async function clone(id, userId = null) {
  return withLock(id, async () => {
    const src = await read(id);
    if (!src) return null;
    if (src.ownerId != null && userId != null && src.ownerId !== userId) return null; // only the owner can clone
    const nid = newId();
    ensureDirs(nid);
    // copy media bytes: object storage (bucket) and/or local disk (whichever holds them)
    if (storageEnabled()) await copyPrefix(`projects/${id}/`, `projects/${nid}/`);
    for (const sub of ["assets", "audio"]) {
      const from = path.join(dir(id), sub);
      if (fs.existsSync(from)) fs.cpSync(from, path.join(dir(nid), sub), { recursive: true });
    }
    // remap every "projects/<old>/…" path (asset/audio/clip srcs) to the new id, then stamp a fresh identity
    const m = JSON.parse(JSON.stringify(src).split(`projects/${id}/`).join(`projects/${nid}/`));
    m.id = nid;
    m.name = `${src.name || "Untitled"} (copy)`;
    m.ownerId = userId ?? src.ownerId ?? null;
    const now = new Date().toISOString();
    m.createdAt = now;
    m.updatedAt = now;
    return write(m); // persists to disk/PG (write also stamps updatedAt)
  });
}

// --- media-file helpers (always on disk; unchanged by the storage backend) ---

export const probe = (file) => {
  try {
    const out = execFileSync("ffprobe", ["-v", "error", "-select_streams", "v:0", "-show_entries", "stream=width,height:format=duration", "-of", "json", file]).toString();
    const j = JSON.parse(out);
    return { width: j.streams?.[0]?.width || 1280, height: j.streams?.[0]?.height || 720, durationMs: Math.round((+j.format?.duration || 5) * 1000) };
  } catch { return { width: 1280, height: 720, durationMs: 5000 }; }
};

// allocate a destination path for an uploaded file inside a project's assets/ or audio/ dir
export function target(id, name, kind = "assets") {
  ensureDirs(id);
  const ext = (path.extname(name || "") || ".mp4").toLowerCase().replace(/[^.\w]/g, "");
  const fid = rid(kind === "audio" ? "a_" : "v_") + ext;
  const rel = `projects/${id}/${kind}/${fid}`;
  return { file: path.join(PUBLIC, rel), src: rel };
}

export const assetId = () => rid("as_");