<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Migration_Finalize_flexible_payroll extends CI_Migration
{
    private function column($table, $column, $definition)
    {
        if ($this->db->table_exists($table) && !$this->db->field_exists($column, $table)) {
            $this->db->query("ALTER TABLE `{$table}` ADD `{$column}` {$definition}");
        }
    }

    private function indexExists($table, $index)
    {
        return (bool) $this->db->query("SHOW INDEX FROM `{$table}` WHERE Key_name=?", array($index))->row();
    }

    private function index($table, $name, $columns, $unique = false)
    {
        if ($this->db->table_exists($table) && !$this->indexExists($table, $name)) {
            $this->db->query('ALTER TABLE `'.$table.'` ADD '.($unique ? 'UNIQUE ' : '').'KEY `'.$name.'` ('.$columns.')');
        }
    }

    public function up()
    {
        foreach (array(
            'attendance_start_date'=>'DATE NULL AFTER `end_date`',
            'attendance_end_date'=>'DATE NULL AFTER `attendance_start_date`',
            'payment_date'=>'DATE NULL AFTER `attendance_end_date`',
            'notes'=>'TEXT NULL AFTER `payment_date`',
            'attendance_locked_by'=>'INT NULL AFTER `notes`',
            'attendance_locked_at'=>'DATETIME NULL AFTER `attendance_locked_by`',
            'calculated_by'=>'INT NULL AFTER `attendance_locked_at`',
            'calculated_at'=>'DATETIME NULL AFTER `calculated_by`',
            'calculation_version'=>'INT NOT NULL DEFAULT 0 AFTER `calculated_at`',
            'updated_at'=>'DATETIME NULL AFTER `created_at`'
        ) as $column=>$definition) $this->column('k_payroll_periods', $column, $definition);

        $this->db->query("UPDATE k_payroll_periods SET attendance_start_date=COALESCE(attendance_start_date,start_date), attendance_end_date=COALESCE(attendance_end_date,end_date), payment_date=COALESCE(payment_date,end_date) WHERE attendance_start_date IS NULL OR attendance_end_date IS NULL OR payment_date IS NULL");
        $this->index('k_payroll_periods', 'idx_payroll_period_range', '`company_id`,`attendance_start_date`,`attendance_end_date`,`workflow_status`');

        foreach (array(
            'period_start_date'=>'DATE NULL AFTER `calculation_snapshot`',
            'period_end_date'=>'DATE NULL AFTER `period_start_date`',
            'structure_version'=>'INT NOT NULL DEFAULT 1 AFTER `period_end_date`'
        ) as $column=>$definition) $this->column('k_payrolls', $column, $definition);
        $this->db->query("UPDATE k_payrolls x JOIN k_payroll_periods p ON p.id=x.payroll_period_id SET x.period_start_date=COALESCE(x.period_start_date,p.attendance_start_date,p.start_date),x.period_end_date=COALESCE(x.period_end_date,p.attendance_end_date,p.end_date)");
        $this->index('k_payrolls', 'idx_payroll_company_period_employee', '`company_id`,`payroll_period_id`,`employee_id`');

        foreach (array(
            'company_id'=>'BIGINT UNSIGNED NULL FIRST',
            'calculation_method'=>"VARCHAR(40) NOT NULL DEFAULT 'fixed' AFTER `category`",
            'default_value'=>'DECIMAL(18,2) NULL AFTER `fixed_amount`',
            'effective_from'=>'DATE NULL AFTER `is_active`',
            'effective_to'=>'DATE NULL AFTER `effective_from`',
            'created_by'=>'INT NULL AFTER `effective_to`',
            'created_at'=>'DATETIME NULL AFTER `created_by`',
            'updated_at'=>'DATETIME NULL AFTER `created_at`'
        ) as $column=>$definition) $this->column('payroll_components', $column, $definition);
        $firstCompany = $this->db->select_min('id', 'id')->get('companies')->row();
        $firstCompanyId = $firstCompany ? (int) $firstCompany->id : 1;
        $this->db->query("UPDATE payroll_components SET company_id=? WHERE company_id IS NULL", array($firstCompanyId));
        if ($this->indexExists('payroll_components', 'uq_payroll_component')) {
            $this->db->query('ALTER TABLE payroll_components DROP INDEX uq_payroll_component');
        }
        $this->index('payroll_components', 'uq_payroll_component_company', '`company_id`,`code`', true);
        $this->index('payroll_components', 'idx_payroll_component_effective', '`company_id`,`is_active`,`effective_from`,`effective_to`');
        $this->db->query("UPDATE payroll_components SET default_value=COALESCE(default_value,fixed_amount),created_at=COALESCE(created_at,NOW())");

        foreach (array(
            'company_id'=>'BIGINT UNSIGNED NULL FIRST',
            'calculation_method'=>"VARCHAR(40) NOT NULL DEFAULT 'fixed' AFTER `component_id`",
            'formula_expression'=>'VARCHAR(500) NULL AFTER `amount_override`',
            'notes'=>'TEXT NULL AFTER `is_active`',
            'created_by'=>'INT NULL AFTER `notes`',
            'created_at'=>'DATETIME NULL AFTER `created_by`',
            'updated_at'=>'DATETIME NULL AFTER `created_at`'
        ) as $column=>$definition) $this->column('employee_payroll_components', $column, $definition);
        $this->db->query("UPDATE employee_payroll_components x JOIN k_employees e ON e.id=x.employee_id SET x.company_id=e.company_id,x.created_at=COALESCE(x.created_at,NOW()) WHERE x.company_id IS NULL OR x.created_at IS NULL");
        $this->index('employee_payroll_components', 'idx_employee_component_scope', '`company_id`,`employee_id`,`component_id`,`is_active`');
        $this->index('employee_payroll_components', 'idx_employee_component_effective', '`company_id`,`effective_from`,`effective_to`');

        $this->db->query("CREATE TABLE IF NOT EXISTS `position_payroll_components` (
            `id` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
            `company_id` BIGINT UNSIGNED NOT NULL,
            `position_id` BIGINT NOT NULL,
            `component_id` BIGINT UNSIGNED NOT NULL,
            `calculation_method` VARCHAR(40) NOT NULL DEFAULT 'fixed',
            `amount_override` DECIMAL(18,2) NULL,
            `formula_expression` VARCHAR(500) NULL,
            `effective_from` DATE NOT NULL,
            `effective_to` DATE NULL,
            `is_active` TINYINT(1) NOT NULL DEFAULT 1,
            `notes` TEXT NULL,
            `created_by` INT NULL,
            `created_at` DATETIME NOT NULL,
            `updated_at` DATETIME NULL,
            PRIMARY KEY (`id`),
            UNIQUE KEY `uq_position_component_version` (`company_id`,`position_id`,`component_id`,`effective_from`),
            KEY `idx_position_component_effective` (`company_id`,`position_id`,`is_active`,`effective_from`,`effective_to`)
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4");

        $this->db->query("CREATE TABLE IF NOT EXISTS `payroll_attendance_rules` (
            `id` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
            `company_id` BIGINT UNSIGNED NOT NULL,
            `component_id` BIGINT UNSIGNED NULL,
            `rule_name` VARCHAR(120) NOT NULL,
            `condition_type` VARCHAR(40) NOT NULL,
            `calculation_method` VARCHAR(40) NOT NULL DEFAULT 'none',
            `tolerance_minutes` INT NOT NULL DEFAULT 0,
            `rate_value` DECIMAL(18,4) NOT NULL DEFAULT 0,
            `maximum_amount` DECIMAL(18,2) NULL,
            `formula_expression` VARCHAR(500) NULL,
            `effective_from` DATE NOT NULL,
            `effective_to` DATE NULL,
            `is_active` TINYINT(1) NOT NULL DEFAULT 1,
            `notes` TEXT NULL,
            `created_by` INT NULL,
            `created_at` DATETIME NOT NULL,
            `updated_at` DATETIME NULL,
            PRIMARY KEY (`id`),
            KEY `idx_attendance_rule_scope` (`company_id`,`condition_type`,`is_active`),
            KEY `idx_attendance_rule_effective` (`company_id`,`effective_from`,`effective_to`),
            KEY `idx_attendance_rule_component` (`component_id`)
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4");

        $this->db->query("CREATE TABLE IF NOT EXISTS `payroll_attendance_locks` (
            `id` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
            `company_id` BIGINT UNSIGNED NOT NULL,
            `payroll_period_id` BIGINT NOT NULL,
            `start_date` DATE NOT NULL,
            `end_date` DATE NOT NULL,
            `status` ENUM('open','locked') NOT NULL DEFAULT 'open',
            `locked_by` INT NULL,
            `locked_at` DATETIME NULL,
            `notes` TEXT NULL,
            PRIMARY KEY (`id`),
            UNIQUE KEY `uq_payroll_attendance_lock_period` (`company_id`,`payroll_period_id`),
            KEY `idx_payroll_attendance_lock_range` (`company_id`,`status`,`start_date`,`end_date`)
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4");

        $this->db->query("CREATE TABLE IF NOT EXISTS `payroll_period_adjustments` (
            `id` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
            `company_id` BIGINT UNSIGNED NOT NULL,
            `payroll_period_id` BIGINT NOT NULL,
            `employee_id` BIGINT NOT NULL,
            `component_id` BIGINT UNSIGNED NOT NULL,
            `adjustment_type` ENUM('earning','deduction') NOT NULL,
            `amount` DECIMAL(18,2) NOT NULL,
            `notes` TEXT NOT NULL,
            `attachment_path` VARCHAR(255) NULL,
            `is_active` TINYINT(1) NOT NULL DEFAULT 1,
            `created_by` INT NULL,
            `created_at` DATETIME NOT NULL,
            `updated_by` INT NULL,
            `updated_at` DATETIME NULL,
            PRIMARY KEY (`id`),
            KEY `idx_period_adjustment_scope` (`company_id`,`payroll_period_id`,`employee_id`,`is_active`),
            KEY `idx_period_adjustment_component` (`component_id`)
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4");

        foreach (array(
            'calculation_method'=>"VARCHAR(40) NOT NULL DEFAULT 'fixed' AFTER `component_type`",
            'source_snapshot'=>'LONGTEXT NULL AFTER `formula_snapshot`',
            'attendance_rule_snapshot'=>'LONGTEXT NULL AFTER `source_snapshot`'
        ) as $column=>$definition) $this->column('payroll_calculation_lines', $column, $definition);
        $this->index('payroll_calculation_lines', 'idx_payroll_line_component', '`component_id`,`component_type`');

        $this->column('payroll_payments', 'company_id', 'BIGINT UNSIGNED NULL FIRST');
        $this->db->query("UPDATE payroll_payments x JOIN k_payroll_periods p ON p.id=x.payroll_period_id SET x.company_id=p.company_id WHERE x.company_id IS NULL");
        $this->index('payroll_payments', 'idx_payroll_payment_company_status', '`company_id`,`status`,`payment_date`');

        // Migrasi satu kali: gaji pokok lama hanya menjadi assignment bila karyawan belum punya struktur gaji.
        $this->db->query("INSERT INTO employee_payroll_components
            (company_id,employee_id,component_id,calculation_method,amount_override,effective_from,effective_to,is_active,notes,created_at)
            SELECT e.company_id,e.id,c.id,'fixed',GREATEST(COALESCE(e.basic_salary,0),0),COALESCE(e.join_date,'2000-01-01'),NULL,1,'Migrasi aman dari k_employees.basic_salary',NOW()
            FROM k_employees e
            JOIN payroll_components c ON c.company_id=e.company_id AND c.code='BASIC'
            WHERE e.company_id IS NOT NULL
              AND NOT EXISTS (SELECT 1 FROM employee_payroll_components x WHERE x.company_id=e.company_id AND x.employee_id=e.id)");

        // Keterlambatan aman secara default: dicatat tetapi tidak otomatis memotong gaji.
        $this->db->query("INSERT INTO payroll_attendance_rules
            (company_id,component_id,rule_name,condition_type,calculation_method,tolerance_minutes,rate_value,effective_from,is_active,notes,created_at)
            SELECT c.id,NULL,'Keterlambatan tanpa potongan','late','none',0,0,'2000-01-01',1,'Default: keterlambatan tidak dipotong sampai aturan diubah.',NOW()
            FROM companies c
            WHERE NOT EXISTS (SELECT 1 FROM payroll_attendance_rules r WHERE r.company_id=c.id AND r.condition_type='late')");

        // Trigger lama tetap dipertahankan sebagai kompatibilitas; rentang fleksibel ditambahkan.
        $rangeConditionNew = "EXISTS(SELECT 1 FROM payroll_attendance_locks l JOIN k_employees e ON e.id=NEW.employee_id WHERE l.company_id=e.company_id AND l.status='locked' AND NEW.attendance_date BETWEEN l.start_date AND l.end_date)";
        $rangeConditionOld = "EXISTS(SELECT 1 FROM payroll_attendance_locks l JOIN k_employees e ON e.id=OLD.employee_id WHERE l.company_id=e.company_id AND l.status='locked' AND OLD.attendance_date BETWEEN l.start_date AND l.end_date)";
        $this->db->query('DROP TRIGGER IF EXISTS trg_attendance_locked_insert');
        $this->db->query("CREATE TRIGGER trg_attendance_locked_insert BEFORE INSERT ON k_attendances FOR EACH ROW BEGIN IF {$rangeConditionNew} OR EXISTS(SELECT 1 FROM attendance_period_locks WHERE period=DATE_FORMAT(NEW.attendance_date,'%Y-%m') AND status='locked' AND branch_id IS NULL) THEN SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT='Attendance period is locked'; END IF; END");
        $this->db->query('DROP TRIGGER IF EXISTS trg_attendance_locked_update');
        $this->db->query("CREATE TRIGGER trg_attendance_locked_update BEFORE UPDATE ON k_attendances FOR EACH ROW BEGIN IF {$rangeConditionOld} OR EXISTS(SELECT 1 FROM attendance_period_locks WHERE period=DATE_FORMAT(OLD.attendance_date,'%Y-%m') AND status='locked' AND branch_id IS NULL) THEN SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT='Attendance period is locked'; END IF; END");
        $this->db->query('DROP TRIGGER IF EXISTS trg_attendance_locked_delete');
        $this->db->query("CREATE TRIGGER trg_attendance_locked_delete BEFORE DELETE ON k_attendances FOR EACH ROW BEGIN IF {$rangeConditionOld} OR EXISTS(SELECT 1 FROM attendance_period_locks WHERE period=DATE_FORMAT(OLD.attendance_date,'%Y-%m') AND status='locked' AND branch_id IS NULL) THEN SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT='Attendance period is locked'; END IF; END");

        // Kolom lama sengaja tidak dihapus. k_employees.basic_salary hanya compatibility mirror/read-only fallback.
    }

    public function down()
    {
        throw new RuntimeException('Migration payroll bersifat data-safe; gunakan backup untuk rollback struktur.');
    }
}