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

const dataDir = path.join(__dirname, 'data');
if (!fs.existsSync(dataDir)) fs.mkdirSync(dataDir, { recursive: true });

const dbPath = path.join(dataDir, 'data.db');
const isNew = !fs.existsSync(dbPath);

const db = new Database(dbPath);
db.pragma('foreign_keys = ON');

const schema = fs.readFileSync(path.join(__dirname, 'schema.sql'), 'utf8');
db.exec(schema);

migrateEmployeeName();
seedInitialAdmin();

if (isNew) {
  seed();
}

// Ältere Deployments hatten ein einzelnes "name"-Feld statt first_name/last_name.
// Bestehende Daten werden erhalten, indem der Name gesplittet statt die Tabelle neu angelegt wird.
function migrateEmployeeName() {
  const columns = db.prepare('PRAGMA table_info(employees)').all().map((c) => c.name);
  if (!columns.includes('name') || columns.includes('first_name')) return;

  db.exec('ALTER TABLE employees ADD COLUMN first_name TEXT');
  db.exec('ALTER TABLE employees ADD COLUMN last_name TEXT');

  const rows = db.prepare('SELECT id, name FROM employees').all();
  const update = db.prepare('UPDATE employees SET first_name = ?, last_name = ? WHERE id = ?');
  for (const row of rows) {
    const parts = (row.name || '').trim().split(/\s+/);
    const first_name = parts.shift() || '';
    const last_name = parts.join(' ');
    update.run(first_name, last_name, row.id);
  }

  db.exec('ALTER TABLE employees DROP COLUMN name');
}

// Legt beim allerersten Start einen Admin-Zugang für einen BESTEHENDEN Mitarbeiter an,
// dessen employees.email mit ADMIN_EMAIL übereinstimmt. Es wird bewusst kein Passwort
// gesetzt: wie bei allen über die Benutzerverwaltung angelegten Konten wird das
// Passwort erst beim allerersten Login vom Nutzer selbst vergeben (siehe /api/auth/login).
function seedInitialAdmin() {
  const userCount = db.prepare('SELECT COUNT(*) AS c FROM users').get().c;
  if (userCount > 0) return;

  const adminEmail = process.env.ADMIN_EMAIL;
  if (!adminEmail) {
    console.log(
      'Hinweis: ADMIN_EMAIL ist nicht gesetzt, es wurde kein Start-Admin angelegt. ' +
        'Bitte ADMIN_EMAIL auf die E-Mail eines bestehenden Mitarbeiters setzen und neu starten, ' +
        'oder scripts/reset-admin.js verwenden.'
    );
    return;
  }

  const employee = db.prepare('SELECT id FROM employees WHERE email = ?').get(adminEmail);
  if (!employee) {
    console.log(
      `Hinweis: ADMIN_EMAIL (${adminEmail}) passt zu keinem bestehenden Mitarbeiter, ` +
        'es wurde kein Start-Admin angelegt.'
    );
    return;
  }

  db.prepare('INSERT INTO users (employee_id, email, password_hash, role) VALUES (?, ?, NULL, ?)').run(
    employee.id,
    adminEmail,
    'admin'
  );
  console.log(`Start-Admin für ${adminEmail} angelegt. Das Passwort wird beim ersten Login vergeben.`);
}

function seed() {
  const insertEmployee = db.prepare(
    'INSERT INTO employees (first_name, last_name, email, role, weekly_capacity_hours) VALUES (?, ?, ?, ?, ?)'
  );
  const employees = [
    ['Anna', 'Keller', 'anna.keller@example.com', 'Frontend-Entwicklerin', 40],
    ['Jonas', 'Weber', 'jonas.weber@example.com', 'Backend-Entwickler', 40],
    ['Mira', 'Schulz', 'mira.schulz@example.com', 'UX-Designerin', 32],
    ['Tom', 'Fischer', 'tom.fischer@example.com', 'Projektleiter', 40],
    ['Lea', 'Hoffmann', 'lea.hoffmann@example.com', 'QA-Ingenieurin', 30],
  ];
  const employeeIds = employees.map((e) => insertEmployee.run(...e).lastInsertRowid);

  const insertTeam = db.prepare('INSERT INTO teams (name, description) VALUES (?, ?)');
  const teamWeb = insertTeam.run('Web-Team', 'Frontend & Backend fürs Kundenportal').lastInsertRowid;
  const teamDesign = insertTeam.run('Design-Team', 'UX/UI und Prototyping').lastInsertRowid;

  const insertMember = db.prepare(
    'INSERT INTO team_members (team_id, employee_id) VALUES (?, ?)'
  );
  insertMember.run(teamWeb, employeeIds[0]);
  insertMember.run(teamWeb, employeeIds[1]);
  insertMember.run(teamWeb, employeeIds[3]);
  insertMember.run(teamDesign, employeeIds[2]);
  insertMember.run(teamDesign, employeeIds[3]);

  const insertProject = db.prepare(
    'INSERT INTO projects (name, description, start_date, end_date, color) VALUES (?, ?, ?, ?, ?)'
  );
  const projectPortal = insertProject.run(
    'Kundenportal Relaunch',
    'Neugestaltung des Self-Service-Portals',
    '2026-07-01',
    '2026-08-28',
    '#4f46e5'
  ).lastInsertRowid;
  const projectApp = insertProject.run(
    'Mobile App v2',
    'Neue Funktionen für die mobile App',
    '2026-07-06',
    '2026-09-18',
    '#059669'
  ).lastInsertRowid;

  const insertTask = db.prepare(
    'INSERT INTO tasks (project_id, name, start_date, end_date, estimated_hours, status) VALUES (?, ?, ?, ?, ?, ?)'
  );
  const t1 = insertTask.run(projectPortal, 'Konzept & Wireframes', '2026-07-01', '2026-07-10', 40, 'in Arbeit').lastInsertRowid;
  const t2 = insertTask.run(projectPortal, 'Frontend-Umsetzung', '2026-07-13', '2026-08-07', 120, 'geplant').lastInsertRowid;
  const t3 = insertTask.run(projectPortal, 'Backend-API', '2026-07-13', '2026-08-07', 100, 'geplant').lastInsertRowid;
  const t4 = insertTask.run(projectPortal, 'QA & Rollout', '2026-08-10', '2026-08-28', 60, 'geplant').lastInsertRowid;

  const t5 = insertTask.run(projectApp, 'Anforderungsanalyse', '2026-07-06', '2026-07-17', 30, 'in Arbeit').lastInsertRowid;
  const t6 = insertTask.run(projectApp, 'Umsetzung Feature-Set', '2026-07-20', '2026-09-04', 150, 'geplant').lastInsertRowid;
  const t7 = insertTask.run(projectApp, 'Test & Release', '2026-09-07', '2026-09-18', 50, 'geplant').lastInsertRowid;

  const insertDependency = db.prepare(
    'INSERT INTO task_dependencies (task_id, depends_on_task_id) VALUES (?, ?)'
  );
  insertDependency.run(t2, t1);
  insertDependency.run(t3, t1);
  insertDependency.run(t4, t2);
  insertDependency.run(t4, t3);
  insertDependency.run(t6, t5);
  insertDependency.run(t7, t6);

  const insertAssignment = db.prepare(
    'INSERT INTO assignments (task_id, employee_id, allocated_hours_per_week) VALUES (?, ?, ?)'
  );
  insertAssignment.run(t1, employeeIds[2], 20);
  insertAssignment.run(t1, employeeIds[3], 10);
  insertAssignment.run(t2, employeeIds[0], 32);
  insertAssignment.run(t3, employeeIds[1], 32);
  insertAssignment.run(t4, employeeIds[4], 24);
  insertAssignment.run(t4, employeeIds[3], 8);
  insertAssignment.run(t5, employeeIds[3], 16);
  insertAssignment.run(t5, employeeIds[2], 12);
  insertAssignment.run(t6, employeeIds[0], 20);
  insertAssignment.run(t6, employeeIds[1], 24);
  insertAssignment.run(t7, employeeIds[4], 24);
}

module.exports = db;