import { DatabaseSync } from "node:sqlite";
import { fileURLToPath } from "node:url";
import path from "node:path";
import fs from "node:fs";

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const dataDir = path.resolve(__dirname, "..", "data");
fs.mkdirSync(dataDir, { recursive: true });
const dbPath = path.join(dataDir, "agendapro.db");

if (process.env.RESET_DB === "1" && fs.existsSync(dbPath)) {
  fs.unlinkSync(dbPath);
}

export const db = new DatabaseSync(dbPath);
db.exec("PRAGMA journal_mode = WAL;");
db.exec("PRAGMA foreign_keys = ON;");

// Fresh-install schema (multi-tenant). For existing v1 DBs, runMigrations() transforms them.
export const SCHEMA = `
CREATE TABLE IF NOT EXISTS meta (
  key TEXT PRIMARY KEY,
  value TEXT NOT NULL
);

CREATE TABLE IF NOT EXISTS businesses (
  id INTEGER PRIMARY KEY,
  name TEXT NOT NULL,
  industry TEXT NOT NULL,
  currency TEXT NOT NULL DEFAULT 'MXN',
  currency_symbol TEXT NOT NULL DEFAULT '$',
  phone TEXT,
  address TEXT,
  slug TEXT,
  plan TEXT NOT NULL DEFAULT 'trial',
  status TEXT NOT NULL DEFAULT 'active',
  template TEXT,
  trial_ends_at TEXT,
  created_at TEXT NOT NULL DEFAULT (datetime('now'))
);

CREATE TABLE IF NOT EXISTS employees (
  id INTEGER PRIMARY KEY,
  business_id INTEGER NOT NULL REFERENCES businesses(id),
  name TEXT NOT NULL,
  email TEXT,
  phone TEXT,
  color TEXT NOT NULL DEFAULT '#3b66ff',
  role TEXT NOT NULL DEFAULT 'specialist',
  active INTEGER NOT NULL DEFAULT 1,
  rating REAL NOT NULL DEFAULT 5.0,
  hire_date TEXT,
  created_at TEXT NOT NULL DEFAULT (datetime('now'))
);

CREATE TABLE IF NOT EXISTS services (
  id INTEGER PRIMARY KEY,
  business_id INTEGER NOT NULL REFERENCES businesses(id),
  name TEXT NOT NULL,
  description TEXT,
  category TEXT NOT NULL DEFAULT 'General',
  duration_min INTEGER NOT NULL DEFAULT 60,
  price REAL NOT NULL DEFAULT 0,
  color TEXT NOT NULL DEFAULT '#3b66ff',
  active INTEGER NOT NULL DEFAULT 1,
  created_at TEXT NOT NULL DEFAULT (datetime('now'))
);

CREATE TABLE IF NOT EXISTS employee_services (
  employee_id INTEGER NOT NULL REFERENCES employees(id) ON DELETE CASCADE,
  service_id INTEGER NOT NULL REFERENCES services(id) ON DELETE CASCADE,
  PRIMARY KEY (employee_id, service_id)
);

CREATE TABLE IF NOT EXISTS users (
  id INTEGER PRIMARY KEY,
  business_id INTEGER REFERENCES businesses(id),
  email TEXT NOT NULL UNIQUE,
  password TEXT NOT NULL,
  name TEXT NOT NULL,
  role TEXT NOT NULL CHECK (role IN ('admin','owner','employee')),
  employee_id INTEGER REFERENCES employees(id),
  avatar_color TEXT NOT NULL DEFAULT '#3b66ff',
  created_at TEXT NOT NULL DEFAULT (datetime('now'))
);

CREATE TABLE IF NOT EXISTS clients (
  id INTEGER PRIMARY KEY,
  business_id INTEGER NOT NULL REFERENCES businesses(id),
  name TEXT NOT NULL,
  email TEXT,
  phone TEXT,
  notes TEXT,
  tags TEXT,
  created_at TEXT NOT NULL DEFAULT (datetime('now'))
);

CREATE TABLE IF NOT EXISTS appointments (
  id INTEGER PRIMARY KEY,
  business_id INTEGER NOT NULL REFERENCES businesses(id),
  service_id INTEGER NOT NULL REFERENCES services(id),
  employee_id INTEGER NOT NULL REFERENCES employees(id),
  client_id INTEGER NOT NULL REFERENCES clients(id),
  start_at TEXT NOT NULL,
  end_at TEXT NOT NULL,
  status TEXT NOT NULL DEFAULT 'scheduled' CHECK (status IN ('scheduled','completed','cancelled','no_show')),
  price REAL NOT NULL DEFAULT 0,
  notes TEXT,
  created_by_user_id INTEGER REFERENCES users(id),
  created_at TEXT NOT NULL DEFAULT (datetime('now')),
  updated_at TEXT NOT NULL DEFAULT (datetime('now'))
);

CREATE INDEX IF NOT EXISTS idx_appointments_start ON appointments(start_at);
CREATE INDEX IF NOT EXISTS idx_appointments_employee ON appointments(employee_id);
CREATE INDEX IF NOT EXISTS idx_appointments_client ON appointments(client_id);
CREATE INDEX IF NOT EXISTS idx_appointments_status ON appointments(status);

CREATE TABLE IF NOT EXISTS reviews (
  id INTEGER PRIMARY KEY,
  appointment_id INTEGER NOT NULL REFERENCES appointments(id) ON DELETE CASCADE,
  client_id INTEGER NOT NULL REFERENCES clients(id),
  employee_id INTEGER NOT NULL REFERENCES employees(id),
  rating INTEGER NOT NULL CHECK (rating BETWEEN 1 AND 5),
  comment TEXT,
  created_at TEXT NOT NULL DEFAULT (datetime('now'))
);

CREATE TABLE IF NOT EXISTS tickets (
  id INTEGER PRIMARY KEY,
  business_id INTEGER NOT NULL REFERENCES businesses(id),
  appointment_id INTEGER REFERENCES appointments(id),
  client_id INTEGER NOT NULL REFERENCES clients(id),
  employee_id INTEGER NOT NULL REFERENCES employees(id),
  service_id INTEGER NOT NULL REFERENCES services(id),
  amount REAL NOT NULL,
  tip REAL NOT NULL DEFAULT 0,
  payment_method TEXT NOT NULL DEFAULT 'card',
  created_at TEXT NOT NULL DEFAULT (datetime('now'))
);

CREATE INDEX IF NOT EXISTS idx_tickets_created ON tickets(created_at);
CREATE INDEX IF NOT EXISTS idx_tickets_employee ON tickets(employee_id);
CREATE INDEX IF NOT EXISTS idx_tickets_client ON tickets(client_id);
`;

export function getMeta(key: string, fallback = ""): string {
  const row = db.prepare(`SELECT value FROM meta WHERE key = ?`).get(key) as { value: string } | undefined;
  return row?.value ?? fallback;
}

export function setMeta(key: string, value: string) {
  db.prepare(`INSERT INTO meta (key, value) VALUES (?, ?) ON CONFLICT(key) DO UPDATE SET value = excluded.value`).run(
    key,
    value
  );
}

function tableExists(name: string): boolean {
  return !!db.prepare(`SELECT name FROM sqlite_master WHERE type='table' AND name=?`).get(name);
}

function columnExists(table: string, column: string): boolean {
  const rows = db.prepare(`PRAGMA table_info(${table})`).all() as { name: string }[];
  return rows.some((r) => r.name === column);
}

/** Migrate an existing v1 DB (single-tenant) to the multi-tenant v2 schema, preserving all data. */
function migrateV1ToV2() {
  if (getMeta("schema_version") >= "2") return;
  if (!tableExists("users")) {
    setMeta("schema_version", "2");
    return;
  }

  // Detect if users table is already v2 (CHECK includes 'admin')
  const usersSql = (db.prepare(`SELECT sql FROM sqlite_master WHERE type='table' AND name='users'`).get() as { sql: string } | undefined)?.sql ?? "";
  const isAlreadyV2 = usersSql.includes("'admin'");

  if (!isAlreadyV2) {
    const fkWasOn = db.prepare("PRAGMA foreign_keys").get() as { foreign_keys: number };
    db.exec("PRAGMA foreign_keys = OFF;");
    try {
      db.exec(`
        CREATE TABLE IF NOT EXISTS users_v2 (
          id INTEGER PRIMARY KEY,
          business_id INTEGER REFERENCES businesses(id),
          email TEXT NOT NULL UNIQUE,
          password TEXT NOT NULL,
          name TEXT NOT NULL,
          role TEXT NOT NULL CHECK (role IN ('admin','owner','employee')),
          employee_id INTEGER REFERENCES employees(id),
          avatar_color TEXT NOT NULL DEFAULT '#3b66ff',
          created_at TEXT NOT NULL DEFAULT (datetime('now'))
        );
      `);
      const existing = db
        .prepare(`SELECT id, business_id, email, password, name, role, employee_id, avatar_color, created_at FROM users`)
        .all() as any[];
      const ins = db.prepare(
        `INSERT OR IGNORE INTO users_v2 (id, business_id, email, password, name, role, employee_id, avatar_color, created_at) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`
      );
      for (const u of existing) {
        ins.run(u.id, u.business_id ?? null, u.email, u.password, u.name, u.role, u.employee_id ?? null, u.avatar_color ?? "#3b66ff", u.created_at);
      }
      db.exec(`DROP TABLE users; ALTER TABLE users_v2 RENAME TO users;`);
    } finally {
      db.exec(`PRAGMA foreign_keys = ${fkWasOn.foreign_keys ? "ON" : "OFF"};`);
    }
  }

  // Add new business columns if missing
  if (!columnExists("businesses", "slug")) db.exec(`ALTER TABLE businesses ADD COLUMN slug TEXT;`);
  if (!columnExists("businesses", "plan")) db.exec(`ALTER TABLE businesses ADD COLUMN plan TEXT NOT NULL DEFAULT 'trial';`);
  if (!columnExists("businesses", "status")) db.exec(`ALTER TABLE businesses ADD COLUMN status TEXT NOT NULL DEFAULT 'active';`);
  if (!columnExists("businesses", "template")) db.exec(`ALTER TABLE businesses ADD COLUMN template TEXT;`);
  if (!columnExists("businesses", "trial_ends_at")) db.exec(`ALTER TABLE businesses ADD COLUMN trial_ends_at TEXT;`);

  // Meta table (created by SCHEMA on fresh; ensure here for migrated DBs)
  db.exec(`CREATE TABLE IF NOT EXISTS meta (key TEXT PRIMARY KEY, value TEXT NOT NULL);`);

  setMeta("schema_version", "2");
}

export function runMigrations() {
  // Ensure base schema exists (no-op on existing tables)
  db.exec(SCHEMA);
  migrateV1ToV2();
  migrateV2ToV3();
}

/** v3: cancellation policy, commissions, cash register, notifications/reminders, booking slug. */
function migrateV2ToV3() {
  if (getMeta("schema_version") >= "3") return;

  // Business-level settings (cancellation policy + deposit + booking enabled)
  const bizCols: [string, string][] = [
    ["booking_enabled", "INTEGER NOT NULL DEFAULT 1"],
    ["cancel_window_hours", "INTEGER NOT NULL DEFAULT 24"],
    ["cancel_penalty_pct", "REAL NOT NULL DEFAULT 0"],
    ["require_deposit", "INTEGER NOT NULL DEFAULT 0"],
    ["deposit_pct", "REAL NOT NULL DEFAULT 0"],
    ["timezone", "TEXT NOT NULL DEFAULT 'America/Mexico_City'"],
  ];
  for (const [col, def] of bizCols) {
    if (!columnExists("businesses", col)) db.exec(`ALTER TABLE businesses ADD COLUMN ${col} ${def};`);
  }
  // Commission rates
  if (!columnExists("services", "commission_pct")) db.exec(`ALTER TABLE services ADD COLUMN commission_pct REAL NOT NULL DEFAULT 0;`);
  if (!columnExists("employees", "commission_pct")) db.exec(`ALTER TABLE employees ADD COLUMN commission_pct REAL NOT NULL DEFAULT 0;`);
  // Commission snapshot on tickets (computed at completion)
  if (!columnExists("tickets", "commission")) db.exec(`ALTER TABLE tickets ADD COLUMN commission REAL NOT NULL DEFAULT 0;`);

  // Cash register
  db.exec(`
    CREATE TABLE IF NOT EXISTS cash_sessions (
      id INTEGER PRIMARY KEY,
      business_id INTEGER NOT NULL REFERENCES businesses(id),
      opened_by_user_id INTEGER REFERENCES users(id),
      opened_at TEXT NOT NULL DEFAULT (datetime('now')),
      closed_at TEXT,
      opening_amount REAL NOT NULL DEFAULT 0,
      closing_amount REAL,
      expected_amount REAL,
      status TEXT NOT NULL DEFAULT 'open' CHECK (status IN ('open','closed')),
      note TEXT
    );
    CREATE INDEX IF NOT EXISTS idx_cash_sessions_business ON cash_sessions(business_id);
    CREATE INDEX IF NOT EXISTS idx_cash_sessions_status ON cash_sessions(status);
    CREATE TABLE IF NOT EXISTS cash_entries (
      id INTEGER PRIMARY KEY,
      business_id INTEGER NOT NULL REFERENCES businesses(id),
      session_id INTEGER REFERENCES cash_sessions(id) ON DELETE CASCADE,
      ticket_id INTEGER REFERENCES tickets(id),
      type TEXT NOT NULL CHECK (type IN ('income','expense')),
      amount REAL NOT NULL,
      concept TEXT NOT NULL,
      payment_method TEXT,
      created_at TEXT NOT NULL DEFAULT (datetime('now'))
    );
    CREATE INDEX IF NOT EXISTS idx_cash_entries_session ON cash_entries(session_id);
    CREATE INDEX IF NOT EXISTS idx_cash_entries_business ON cash_entries(business_id);
  `);

  // Reminders / notifications center
  db.exec(`
    CREATE TABLE IF NOT EXISTS notifications (
      id INTEGER PRIMARY KEY,
      business_id INTEGER NOT NULL REFERENCES businesses(id),
      appointment_id INTEGER REFERENCES appointments(id) ON DELETE CASCADE,
      client_id INTEGER REFERENCES clients(id),
      channel TEXT NOT NULL CHECK (channel IN ('whatsapp','sms','email')),
      kind TEXT NOT NULL CHECK (kind IN ('confirmation','reminder','cancellation','follow_up','review')),
      send_at TEXT NOT NULL,
      status TEXT NOT NULL DEFAULT 'pending' CHECK (status IN ('pending','sent','failed','canceled')),
      message TEXT,
      created_at TEXT NOT NULL DEFAULT (datetime('now'))
    );
    CREATE INDEX IF NOT EXISTS idx_notif_send ON notifications(send_at);
    CREATE INDEX IF NOT EXISTS idx_notif_business ON notifications(business_id);
    CREATE INDEX IF NOT EXISTS idx_notif_status ON notifications(status);
  `);

  // Ensure every business has a slug (for public booking /b/:slug)
  const bizs = db.prepare(`SELECT id, name, slug FROM businesses WHERE slug IS NULL OR slug = ''`).all() as any[];
  const slugify = (s: string) =>
    s.toLowerCase().normalize("NFD").replace(/[\u0300-\u036f]/g, "").replace(/[^a-z0-9]+/g, "-").replace(/^-+|-+$/g, "").slice(0, 40) || `negocio`;
  for (const b of bizs) {
    let slug = slugify(b.name);
    let n = 1;
    while (db.prepare(`SELECT id FROM businesses WHERE slug = ? AND id != ?`).get(slug, b.id)) {
      slug = `${slugify(b.name)}-${n++}`;
    }
    db.prepare(`UPDATE businesses SET slug = ? WHERE id = ?`).run(slug, b.id);
  }

  setMeta("schema_version", "3");
}

runMigrations();