// Achievements engine — subscribes to bus events, unlocks achievements.
// On unlock: pushes id into State, emits 'achievement:unlocked' for the widget.

import Bus from '../core/bus.js';
import State from '../core/state.js';
import catalog from './catalog.js';

// In-memory counters per achievement id
const counters = {};
// For uniqueField tracking: Set of seen values per achievement id
const uniqueSets = {};
// For speedrun: map of windowId -> open timestamp
const openTimestamps = {};

let initialized = false;

function hasUnlocked(id) {
  const unlocked = State.get('achievements');
  return unlocked && unlocked.includes(id);
}

function unlock(ach) {
  if (hasUnlocked(ach.id)) return;
  State.addAchievement(ach.id);
  Bus.emit('achievement:unlocked', {
    id: ach.id,
    title: ach.title,
    desc: ach.desc,
    game: ach.game
  });
}

function handleEvent(ach, data) {
  const trigger = ach.trigger;

  // Event+id specific trigger (easter egg matches)
  if (trigger.id) {
    if (data && data.id === trigger.id) {
      unlock(ach);
    }
    return;
  }

  // Simple event trigger (no count, no accumulate) — unlock on first fire
  if (!trigger.count && !trigger.accumulate && !trigger.uniqueField) {
    unlock(ach);
    return;
  }

  // Count-based trigger
  if (trigger.count) {
    counters[ach.id] = (counters[ach.id] || 0) + 1;
    if (counters[ach.id] >= trigger.count) {
      unlock(ach);
    }
    return;
  }

  // UniqueField trigger
  if (trigger.uniqueField) {
    if (!uniqueSets[ach.id]) {
      uniqueSets[ach.id] = new Set();
    }
    const val = data && data[trigger.uniqueField];
    if (val) {
      uniqueSets[ach.id].add(val);
      if (uniqueSets[ach.id].size >= trigger.count) {
        unlock(ach);
      }
    }
    return;
  }

  // Accumulate trigger
  if (trigger.accumulate) {
    const key = trigger.accumulate;
    const value = data && data[key];
    if (typeof value === 'number') {
      counters[ach.id] = (counters[ach.id] || 0) + value;
      if (counters[ach.id] >= trigger.threshold) {
        unlock(ach);
      }
    }
    return;
  }
}

function init() {
  if (initialized) return;
  initialized = true;

  // Pre-initialize counters for all achievements
  catalog.forEach(ach => {
    counters[ach.id] = 0;
    uniqueSets[ach.id] = ach.trigger.uniqueField ? new Set() : undefined;
  });

  // Subscribe to each achievement's trigger event
  catalog.forEach(ach => {
    const trigger = ach.trigger;
    if (trigger.custom === 'speedrun') {
      // Speedrun: listen to app:open and app:close on wm.js
      Bus.on('app:open', (data) => {
        if (data && data.id) {
          openTimestamps[data.id] = Date.now();
        }
      });
      Bus.on('app:close', (data) => {
        if (data && data.id && openTimestamps[data.id]) {
          const delta = Date.now() - openTimestamps[data.id];
          if (delta < 2000) {
            unlock(ach);
          }
          delete openTimestamps[data.id];
        }
      });
      return;
    }

    if (trigger.event) {
      Bus.on(trigger.event, (data) => {
        handleEvent(ach, data);
      });
    }
  });
}

export default { init };