CREATE TABLE IF NOT EXISTS departments (
  id INT AUTO_INCREMENT PRIMARY KEY,
  name VARCHAR(120) NOT NULL UNIQUE,
  created_at DATETIME NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

CREATE TABLE IF NOT EXISTS users (
  id INT AUTO_INCREMENT PRIMARY KEY,
  username VARCHAR(80) NOT NULL UNIQUE,
  password_hash VARCHAR(255) NOT NULL,
  full_name VARCHAR(160) NOT NULL,
  email VARCHAR(190) NOT NULL,
  role ENUM('mitarbeiter','bauleiter','buero','geschaeftsfuehrung','admin') NOT NULL DEFAULT 'mitarbeiter',
  department_id INT NULL,
  vacation_days DECIMAL(5,2) NOT NULL DEFAULT 30,
  carryover_days DECIMAL(5,2) NOT NULL DEFAULT 0,
  must_change_password TINYINT(1) NOT NULL DEFAULT 1,
  two_factor_enabled TINYINT(1) NOT NULL DEFAULT 0,
  active TINYINT(1) NOT NULL DEFAULT 1,
  last_login_at DATETIME NULL,
  created_at DATETIME NOT NULL,
  updated_at DATETIME NULL,
  CONSTRAINT fk_users_department FOREIGN KEY (department_id) REFERENCES departments(id) ON DELETE SET NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

CREATE TABLE IF NOT EXISTS absences (
  id INT AUTO_INCREMENT PRIMARY KEY,
  user_id INT NOT NULL,
  type VARCHAR(80) NOT NULL,
  status ENUM('offen','genehmigt','abgelehnt','zurueckgezogen','storniert') NOT NULL DEFAULT 'offen',
  start_date DATE NOT NULL,
  end_date DATE NOT NULL,
  day_part ENUM('ganzer_tag','halber_tag') NOT NULL DEFAULT 'ganzer_tag',
  days_count DECIMAL(6,2) NOT NULL DEFAULT 0,
  comment TEXT NULL,
  decided_by INT NULL,
  decided_at DATETIME NULL,
  decision_note TEXT NULL,
  created_at DATETIME NOT NULL,
  updated_at DATETIME NULL,
  CONSTRAINT fk_absences_user FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
  CONSTRAINT fk_absences_decider FOREIGN KEY (decided_by) REFERENCES users(id) ON DELETE SET NULL,
  INDEX idx_absences_dates (start_date, end_date),
  INDEX idx_absences_status (status)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

CREATE TABLE IF NOT EXISTS absence_types (
  id INT AUTO_INCREMENT PRIMARY KEY,
  code VARCHAR(80) NOT NULL UNIQUE,
  label VARCHAR(120) NOT NULL,
  requires_approval TINYINT(1) NOT NULL DEFAULT 1,
  reduces_vacation TINYINT(1) NOT NULL DEFAULT 0,
  active TINYINT(1) NOT NULL DEFAULT 1,
  sort_order INT NOT NULL DEFAULT 100,
  created_at DATETIME NOT NULL,
  updated_at DATETIME NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

CREATE TABLE IF NOT EXISTS audit_logs (
  id BIGINT AUTO_INCREMENT PRIMARY KEY,
  user_id INT NULL,
  action VARCHAR(120) NOT NULL,
  entity_type VARCHAR(80) NULL,
  entity_id INT NULL,
  ip_address VARCHAR(64) NULL,
  payload JSON NULL,
  created_at DATETIME NOT NULL,
  INDEX idx_audit_created (created_at),
  CONSTRAINT fk_audit_user FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE SET NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;