// server/db.js — SQLite persistence layer.
// Owns the DB file. Only writer. Synchronous via better-sqlite3.
//
// Schema mirrors the Firestore doc tree used by src/App.js:
//   artifacts/{APP_ID}/public/data/
//     campaigns/{id}                       -> name, bg, ownerId, createdAt, players[]
//     campaigns/{id}/encounters/{eid}      -> name, participants[], round, currentTurnParticipantId, isStarted, isPaused, turnOrderIds[]
//     activeDisplay/status                 -> activeCampaignId, activeEncounterId, hidePlayerHp
//     logs/{id}                            -> timestamp, message, encounterName, undo, undone
//
// Collections (campaigns, encounters, logs) -> rows with JSON blobs for fields.
// Single-row "status" docs (activeDisplay) -> their own tables.

'use strict';

const Database = require('better-sqlite3');
const path = require('path');
const fs = require('fs');

const SCHEMA = `
CREATE TABLE IF NOT EXISTS campaigns (
  id TEXT PRIMARY KEY,
  name TEXT NOT NULL,
  playerDisplayBackgroundUrl TEXT NOT NULL DEFAULT '',
  ownerId TEXT,
  createdAt TEXT NOT NULL,
  players TEXT NOT NULL DEFAULT '[]'
);

CREATE TABLE IF NOT EXISTS encounters (
  id TEXT NOT NULL,
  campaignId TEXT NOT NULL,
  name TEXT NOT NULL,
  participants TEXT NOT NULL DEFAULT '[]',
  round INTEGER NOT NULL DEFAULT 0,
  currentTurnParticipantId TEXT,
  isStarted INTEGER NOT NULL DEFAULT 0,
  isPaused INTEGER NOT NULL DEFAULT 0,
  turnOrderIds TEXT NOT NULL DEFAULT '[]',
  createdAt TEXT NOT NULL,
  PRIMARY KEY (campaignId, id),
  FOREIGN KEY (campaignId) REFERENCES campaigns(id) ON DELETE CASCADE
);

CREATE TABLE IF NOT EXISTS active_display (
  id INTEGER PRIMARY KEY CHECK (id = 1),
  activeCampaignId TEXT,
  activeEncounterId TEXT,
  hidePlayerHp INTEGER NOT NULL DEFAULT 1
);

CREATE TABLE IF NOT EXISTS logs (
  id TEXT PRIMARY KEY,
  timestamp INTEGER NOT NULL,
  message TEXT NOT NULL,
  encounterName TEXT,
  undo TEXT,
  undone INTEGER NOT NULL DEFAULT 0
);

CREATE INDEX IF NOT EXISTS idx_logs_timestamp ON logs(timestamp DESC);
CREATE INDEX IF NOT EXISTS idx_encounters_campaign ON encounters(campaignId);
`;

function openDb(dbPath) {
  const dir = path.dirname(dbPath);
  if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
  const db = new Database(dbPath);
  db.pragma('journal_mode = WAL');
  db.pragma('foreign_keys = ON');
  db.exec(SCHEMA);
  // Ensure the single active_display row exists.
  db.prepare('INSERT OR IGNORE INTO active_display (id, hidePlayerHp) VALUES (1, 1)').run();
  return db;
}

// --- JSON helpers ---
const parseArr = (s) => (s ? JSON.parse(s) : []);
const parseObj = (s, fallback = null) => (s ? JSON.parse(s) : fallback);

// --- Campaign shape (matches Firestore doc) ---
function rowToCampaign(row) {
  if (!row) return null;
  return {
    id: row.id,
    name: row.name,
    playerDisplayBackgroundUrl: row.playerDisplayBackgroundUrl,
    ownerId: row.ownerId,
    createdAt: row.createdAt,
    players: parseArr(row.players),
  };
}

// --- Encounter shape (matches Firestore doc) ---
function rowToEncounter(row) {
  if (!row) return null;
  return {
    id: row.id,
    campaignId: row.campaignId,
    name: row.name,
    participants: parseArr(row.participants),
    round: row.round,
    currentTurnParticipantId: row.currentTurnParticipantId,
    isStarted: !!row.isStarted,
    isPaused: !!row.isPaused,
    turnOrderIds: parseArr(row.turnOrderIds),
    createdAt: row.createdAt,
  };
}

// --- Active display shape ---
function rowToActiveDisplay(row) {
  if (!row) return null;
  return {
    activeCampaignId: row.activeCampaignId,
    activeEncounterId: row.activeEncounterId,
    hidePlayerHp: !!row.hidePlayerHp,
  };
}

module.exports = {
  openDb,
  rowToCampaign,
  rowToEncounter,
  rowToActiveDisplay,
};