import { createStore } from './createStore.js';
import { settings } from './settings.js';

/**
 * Per-game Pokémon tracking.
 *
 * Seen / caught are stored *per game* (PokéAPI version-group key) — catching
 * Pikachu in Blue says nothing about your Gold save. `favorite` and `note`
 * are the exception: those describe the Pokémon itself, so they're global,
 * one record keyed by National dex id.
 *
 *   pokemon: { [id]: { favorite, note, updatedAt } }          // global
 *   games:   { [vgKey]: { [id]: { seen, caught, updatedAt } } } // per game
 *
 * The 'all' key ("All games" / National mode) is special: reading it returns
 * the union of every game — "have I caught this anywhere". It's also a real
 * bucket you write to when you mark something while no specific game is
 * selected (and where a pre-per-game save's data was migrated to).
 */
export const selection = createStore('pdx.selection', {
  version: 3,
  pokemon: {},
  games: {},
});

const GBLANK = { seen: false, caught: false };
const PBLANK = { favorite: false, note: '' };

/** Convert any older (flat, one-record) shape to the current per-game one. */
export function normalizeSelection(raw) {
  if (!raw || typeof raw !== 'object') return { version: 3, pokemon: {}, games: {} };
  if (raw.version >= 3 && raw.games) {
    return { version: 3, pokemon: raw.pokemon || {}, games: raw.games || {} };
  }
  const pokemon = {};
  const all = {};
  for (const [id, e] of Object.entries(raw.pokemon || {})) {
    if (e.favorite || (e.note && String(e.note).trim())) {
      pokemon[id] = { favorite: !!e.favorite, note: e.note || '', updatedAt: e.updatedAt };
    }
    if (e.seen || e.caught) {
      all[id] = { seen: !!e.seen, caught: !!e.caught, updatedAt: e.updatedAt };
    }
  }
  return { version: 3, pokemon, games: Object.keys(all).length ? { all } : {} };
}

// One-time migration of an existing v2 store on this device.
{
  const cur = selection.get();
  if (!cur || cur.version < 3 || !cur.games) selection.replace(normalizeSelection(cur));
}

function curGame() {
  return settings.get().versionGroup || 'all';
}

function unionEntry(id) {
  const games = selection.get().games;
  let seen = false;
  let caught = false;
  let updatedAt = '';
  for (const k in games) {
    const e = games[k][id];
    if (!e) continue;
    if (e.seen || e.caught) seen = true;
    if (e.caught) caught = true;
    if (e.updatedAt && e.updatedAt > updatedAt) updatedAt = e.updatedAt;
  }
  return { seen, caught, updatedAt };
}

/** Raw seen/caught for one game (union when vgKey === 'all'). */
export function gameEntry(id, vgKey = curGame()) {
  if (vgKey === 'all') return unionEntry(id);
  return selection.get().games[vgKey]?.[id] || GBLANK;
}

/** Merged view for a game: its seen/caught + the global favorite/note. */
export function entry(id, vgKey = curGame()) {
  const g = gameEntry(id, vgKey);
  const p = selection.get().pokemon[id] || PBLANK;
  return { seen: !!g.seen, caught: !!g.caught, favorite: !!p.favorite, note: p.note || '' };
}

export function toggle(id, field, vgKey = curGame()) {
  selection.set((s) => {
    const stamp = new Date().toISOString();
    if (field === 'favorite') {
      const cur = s.pokemon[id] || PBLANK;
      return {
        ...s,
        pokemon: { ...s.pokemon, [id]: { ...cur, favorite: !cur.favorite, updatedAt: stamp } },
      };
    }
    const bucket = s.games[vgKey] || {};
    const cur = bucket[id] || GBLANK;
    const next = { ...cur, [field]: !cur[field], updatedAt: stamp };
    if (field === 'caught' && next.caught) next.seen = true;
    return { ...s, games: { ...s.games, [vgKey]: { ...bucket, [id]: next } } };
  });
}

export function setNote(id, note) {
  selection.set((s) => {
    const cur = s.pokemon[id] || PBLANK;
    return {
      ...s,
      pokemon: { ...s.pokemon, [id]: { ...cur, note, updatedAt: new Date().toISOString() } },
    };
  });
}

/**
 * Merge seen/caught lists into one game's bucket (a save-file import).
 * Never clears. `game` defaults to the selected one.
 */
export function importFlags({ seen = [], caught = [], game } = {}) {
  const vgKey = game || curGame();
  selection.set((s) => {
    const stamp = new Date().toISOString();
    const bucket = { ...(s.games[vgKey] || {}) };
    for (const id of seen) bucket[id] = { ...(bucket[id] || GBLANK), seen: true, updatedAt: stamp };
    for (const id of caught)
      bucket[id] = { ...(bucket[id] || GBLANK), seen: true, caught: true, updatedAt: stamp };
    return { ...s, games: { ...s.games, [vgKey]: bucket } };
  });
}

/** Set one game's bucket to exactly these lists (a "replace with this save" import). */
export function replaceFlags({ seen = [], caught = [], game } = {}) {
  const vgKey = game || curGame();
  selection.set((s) => {
    const stamp = new Date().toISOString();
    const bucket = {};
    for (const id of seen) bucket[id] = { seen: true, caught: false, updatedAt: stamp };
    for (const id of caught) bucket[id] = { seen: true, caught: true, updatedAt: stamp };
    return { ...s, games: { ...s.games, [vgKey]: bucket } };
  });
}

/** Drop one game's seen/caught bucket entirely (its own progress reset). */
export function clearGame(vgKey) {
  selection.set((s) => {
    if (!s.games[vgKey]) return s;
    const games = { ...s.games };
    delete games[vgKey];
    return { ...s, games };
  });
}

/**
 * Wipe seen/caught for every game (a "National Dex reset"). Favorites and
 * notes — the global `pokemon` record — are kept. Use `selection.replace`
 * for the full wipe that also drops those.
 */
export function clearAllGames() {
  selection.set((s) => ({ ...s, games: {} }));
}

/** Aggregate seen/caught over a species list for one game (union when 'all'). */
export function stats(speciesIds, vgKey = curGame()) {
  const get = vgKey === 'all' ? unionEntry : (id) => selection.get().games[vgKey]?.[id] || GBLANK;
  let seen = 0;
  let caught = 0;
  for (const id of speciesIds) {
    const e = get(id);
    if (e.seen || e.caught) seen++;
    if (e.caught) caught++;
  }
  return { seen, caught, total: speciesIds.length };
}

/** Caught/seen across every game — the true National Dex tally. */
export function statsNational(speciesIds) {
  return stats(speciesIds, 'all');
}