// server/index.js — Express (HTTP) + ws (WebSocket) bootstrap.
// HTTP: REST-ish endpoints for actions. WS: real-time state push (replaces onSnapshot).
//
// Env:
//   PORT (default 4001)
//   DB_PATH (default ./data/tracker.sqlite)
//   CORS_ORIGIN (default '*'; in-house only)

'use strict';

const express = require('express');
const cors = require('cors');
const http = require('http');
const { WebSocketServer } = require('ws');
const { openDb } = require('./db');
const { createStore } = require('./handlers');

function createServer({ dbPath, port, corsOrigin } = {}) {
  const db = openDb(dbPath || './data/tracker.sqlite');
  const app = express();
  app.use(cors({ origin: corsOrigin || '*' }));
  app.use(express.json({ limit: '1mb' }));

  // WS subscribers. Map: key -> Set<ws>. key = 'campaigns' | 'campaign:id' | etc.
  const subscribers = new Map();
  function subscribe(key, ws) {
    if (!subscribers.has(key)) subscribers.set(key, new Set());
    subscribers.get(key).add(ws);
  }
  function unsubscribe(key, ws) {
    const set = subscribers.get(key);
    if (set) { set.delete(ws); if (set.size === 0) subscribers.delete(key); }
  }
  function broadcast(change) {
    const set = subscribers.get(change.type) || new Set();
    // 'encounter'/'campaign' changes also notify bare type subscribers.
    [...set].forEach(ws => { if (ws.readyState === ws.OPEN) ws.send(JSON.stringify({ type: 'change', change })); });
  }

  const store = createStore(db, broadcast);

  // --- REST read endpoints ---
  app.get('/health', (req, res) => res.json({ ok: true }));
  app.get('/api/campaigns', (req, res) => res.json(store.listCampaigns()));
  app.get('/api/campaigns/:campaignId', (req, res) => {
    const c = store.getCampaign(req.params.campaignId);
    if (!c) return res.status(404).json({ error: 'Not found' });
    res.json(c);
  });
  app.get('/api/campaigns/:campaignId/encounters', (req, res) => res.json(store.listEncounters(req.params.campaignId)));
  app.get('/api/campaigns/:campaignId/encounters/:encounterId', (req, res) => {
    const e = store.getEncounter(req.params.campaignId, req.params.encounterId);
    if (!e) return res.status(404).json({ error: 'Not found' });
    res.json(e);
  });
  app.get('/api/activeDisplay', (req, res) => res.json(store.getActiveDisplay()));
  app.get('/api/logs', (req, res) => res.json(store.listLogs(parseInt(req.query.limit, 10) || 500)));

  // --- campaign mutations ---
  app.post('/api/campaigns', (req, res) => {
    try { res.json(store.createCampaign(req.body)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.delete('/api/campaigns/:campaignId', (req, res) => {
    try { store.deleteCampaign(req.params.campaignId); res.json({ ok: true }); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.post('/api/campaigns/:campaignId/characters', (req, res) => {
    try { res.json(store.addCampaignCharacter(req.params.campaignId, req.body)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.put('/api/campaigns/:campaignId/characters/:characterId', (req, res) => {
    try { store.updateCampaignCharacter(req.params.campaignId, req.params.characterId, req.body); res.json({ ok: true }); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.delete('/api/campaigns/:campaignId/characters/:characterId', (req, res) => {
    try { store.deleteCampaignCharacter(req.params.campaignId, req.params.characterId); res.json({ ok: true }); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });

  // --- encounter mutations ---
  app.post('/api/campaigns/:campaignId/encounters', (req, res) => {
    try { res.json(store.createEncounter(req.params.campaignId, req.body.name)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.delete('/api/campaigns/:campaignId/encounters/:encounterId', (req, res) => {
    try { store.deleteEncounter(req.params.campaignId, req.params.encounterId); res.json({ ok: true }); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/display', (req, res) => {
    try { store.togglePlayerDisplay(req.params.campaignId, req.params.encounterId); res.json({ ok: true }); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });

  // --- participant mutations ---
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/participants', (req, res) => {
    try { res.json(store.addParticipant(req.params.campaignId, req.params.encounterId, req.body)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/participants/addAll', (req, res) => {
    try { res.json(store.addAllCampaignCharacters(req.params.campaignId, req.params.encounterId)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.put('/api/campaigns/:campaignId/encounters/:encounterId/participants/:participantId', (req, res) => {
    try { res.json(store.updateParticipant(req.params.campaignId, req.params.encounterId, req.params.participantId, req.body)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.delete('/api/campaigns/:campaignId/encounters/:encounterId/participants/:participantId', (req, res) => {
    try { res.json(store.removeParticipant(req.params.campaignId, req.params.encounterId, req.params.participantId)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/participants/:participantId/active', (req, res) => {
    try { res.json(store.toggleParticipantActive(req.params.campaignId, req.params.encounterId, req.params.participantId)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/participants/:participantId/hp', (req, res) => {
    try { res.json(store.applyHpChange(req.params.campaignId, req.params.encounterId, req.params.participantId, req.body.changeType, req.body.amount)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/participants/:participantId/deathSave', (req, res) => {
    try { res.json(store.deathSave(req.params.campaignId, req.params.encounterId, req.params.participantId, req.body.saveNumber)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/participants/:participantId/condition', (req, res) => {
    try { res.json(store.toggleCondition(req.params.campaignId, req.params.encounterId, req.params.participantId, req.body.conditionId)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/reorder', (req, res) => {
    try { res.json(store.reorderParticipants(req.params.campaignId, req.params.encounterId, req.body.draggedId, req.body.targetId)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });

  // --- combat controls ---
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/start', (req, res) => {
    try { res.json(store.startEncounter(req.params.campaignId, req.params.encounterId)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/nextTurn', (req, res) => {
    try { res.json(store.nextTurn(req.params.campaignId, req.params.encounterId)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/pause', (req, res) => {
    try { res.json(store.togglePause(req.params.campaignId, req.params.encounterId)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.post('/api/campaigns/:campaignId/encounters/:encounterId/end', (req, res) => {
    try { res.json(store.endEncounter(req.params.campaignId, req.params.encounterId)); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });

  // --- display + logs ---
  app.post('/api/activeDisplay/hidePlayerHp', (req, res) => {
    try { res.json({ hidePlayerHp: store.toggleHidePlayerHp() }); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });
  app.delete('/api/logs', (req, res) => {
    try { store.clearLogs(); res.json({ ok: true }); }
    catch (err) { res.status(400).json({ error: err.message }); }
  });

  // --- WebSocket: real-time push ---
  const server = http.createServer(app);
  const wss = new WebSocketServer({ server, path: '/ws' });

  wss.on('connection', (ws) => {
    ws.on('message', (raw) => {
      let msg;
      try { msg = JSON.parse(raw.toString()); } catch { ws.send(JSON.stringify({ type: 'error', error: 'bad json' })); return; }
      if (msg.type === 'subscribe' && msg.key) {
        subscribe(msg.key, ws);
        ws.send(JSON.stringify({ type: 'subscribed', key: msg.key }));
      } else if (msg.type === 'unsubscribe' && msg.key) {
        unsubscribe(msg.key, ws);
      }
    });
    ws.on('close', () => {
      for (const [key, set] of subscribers) { set.delete(ws); if (set.size === 0) subscribers.delete(key); }
    });
    ws.on('error', () => {});
  });

  return {
    app, server, wss, store, db,
    close(done) { wss.close(); server.close(() => { db.close(); if (done) done(); }); },
  };
}

// Boot standalone if run directly.
if (require.main === module) {
  const port = parseInt(process.env.PORT, 10) || 4001;
  const dbPath = process.env.DB_PATH || './data/tracker.sqlite';
  const { server } = createServer({ dbPath, port });
  server.listen(port, () => {
    console.log(`ttrpg backend listening on :${port} (db: ${dbPath})`);
  });
}

module.exports = { createServer };