import type { CropRatio, CropRect, FrameId, GPSInfo, Recipe } from '../../shared/types';

// Studio session: the working photo plus every knob the workspace holds, so a
// reload resumes exactly where the user left off — guest or signed in (the
// login cookie already outlives the tab; this covers the rest).
//
// ponytail: one session per browser, not per account — two accounts in the same
// browser share the working photo. Key it by user id if that ever matters.
const STATE_KEY = 'rc.studio.v1';
const DB_NAME = 'recipescam-studio';
const STORE = 'session';
const PHOTO_KEY = 'photo';

export interface StudioState {
  recipe?: Recipe;
  simId?: string | null;
  frameId?: FrameId;
  crop?: CropRatio;
  cropRect?: CropRect;
  // false = the frame is on screen but not accepted yet (still draggable).
  cropApplied?: boolean;
  rotation?: 0 | 90 | 180 | 270;
  // FRAME's STRAIGHTEN: degrees off the quarter turn, -180..180.
  straighten?: number;
  gps?: GPSInfo | null;
  gpsManual?: { lat: string; lng: string };
  place?: string;
  useGeotag?: boolean;
  // size/x/y are the GPS box on the photo; older sessions hold only the colour
  // and the two switches and take the defaults for the rest. font is the family
  // the FONT strip picked, null for the bundled face.
  gpsStyle?: { color: string; showName: boolean; showTime: boolean; size?: number; x?: number; y?: number; font?: string | null };
  markText?: string;
  markOn?: boolean;
  // x/y are fractions of the stamp the mark is drawn on (the drag box writes
  // them straight back); older sessions hold no x/y and take the default.
  markStyle?: { color: string; size: number; x?: number; y?: number; font?: string | null };
}

export function loadState(): StudioState {
  try {
    const raw = localStorage.getItem(STATE_KEY);
    return raw ? (JSON.parse(raw) as StudioState) : {};
  } catch {
    return {};
  }
}

export function saveState(state: StudioState): void {
  try {
    localStorage.setItem(STATE_KEY, JSON.stringify(state));
  } catch {
    // Quota or private mode: the studio still works, it just forgets.
  }
}

// --- the photo: IndexedDB, because a 12MP JPEG does not fit in localStorage ---
function openDb(): Promise<IDBDatabase> {
  return new Promise((resolve, reject) => {
    const req = indexedDB.open(DB_NAME, 1);
    req.onupgradeneeded = () => req.result.createObjectStore(STORE);
    req.onsuccess = () => resolve(req.result);
    req.onerror = () => reject(req.error);
  });
}

async function idb<T>(mode: IDBTransactionMode, run: (store: IDBObjectStore) => IDBRequest): Promise<T> {
  const db = await openDb();
  try {
    return await new Promise<T>((resolve, reject) => {
      const req = run(db.transaction(STORE, mode).objectStore(STORE));
      req.onsuccess = () => resolve(req.result as T);
      req.onerror = () => reject(req.error);
    });
  } finally {
    db.close();
  }
}

export async function savePhoto(name: string, bytes: Uint8Array): Promise<void> {
  try {
    await idb('readwrite', (s) => s.put({ name, bytes }, PHOTO_KEY));
  } catch {
    // Private mode / no IndexedDB: the photo just will not survive a reload.
  }
}

export async function loadPhoto(): Promise<{ name: string; bytes: Uint8Array } | null> {
  try {
    const row = await idb<{ name: string; bytes: Uint8Array } | undefined>('readonly', (s) => s.get(PHOTO_KEY));
    return row && row.bytes instanceof Uint8Array ? { name: row.name, bytes: row.bytes } : null;
  } catch {
    return null;
  }
}

// CLEAR takes the working photo off the stage but keeps the knobs: the look was
// the user's work and outlives the picture it was made on. The session's own
// copy has to go with it, or the next reload would put the frame straight back.
export async function forgetPhoto(): Promise<void> {
  try {
    await idb('readwrite', (s) => s.delete(PHOTO_KEY));
  } catch {
    // Private mode / no IndexedDB: the photo just will not survive a reload.
  }
}

// Signing out ends the session: drop the knobs and the working photo, so the
// next visit — guest or another account — opens the studio empty. The account's
// own photos stay in MY PHOTOS, ready to reopen.
//
// Async on purpose: the caller reloads the moment this returns, and a reload
// aborts a delete still in flight. Resolve on the transaction's completion, not
// on the request's success, or the bytes outlive the logout.
export async function clearSession(): Promise<void> {
  try {
    localStorage.removeItem(STATE_KEY);
  } catch {
    // Nothing to clear.
  }
  try {
    const db = await openDb();
    await new Promise<void>((resolve, reject) => {
      const tx = db.transaction(STORE, 'readwrite');
      tx.objectStore(STORE).delete(PHOTO_KEY);
      tx.oncomplete = () => resolve();
      tx.onerror = () => reject(tx.error);
      tx.onabort = () => reject(tx.error);
    });
    db.close();
  } catch {
    // Private mode / no IndexedDB: there is nothing stored to forget.
  }
}