<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

class PaymentOrder extends Model
{
    use HasFactory;

    protected $attributes = [
        'status' => self::STATUS_DRAFT,
        'verification_status' => self::VERIFICATION_PENDING,
        'execution_status' => self::EXECUTION_PENDING,
    ];

    protected $fillable = [
        'finance_document_id',
        'payee_name',
        'payee_bank_code',
        'payee_account_number',
        'payee_bank_name',
        'payment_amount',
        'payment_method',
        'created_by_accountant_id',
        'payment_order_number',
        'notes',
        'verified_by_cashier_id',
        'verified_at',
        'verification_status',
        'verification_notes',
        'executed_by_cashier_id',
        'executed_at',
        'execution_status',
        'transaction_reference',
        'payment_receipt_path',
        'status',
    ];

    protected $casts = [
        'payment_amount' => 'decimal:2',
        'verified_at' => 'datetime',
        'executed_at' => 'datetime',
    ];

    /**
     * 狀態常數
     */
    const STATUS_DRAFT = 'draft';
    const STATUS_PENDING_VERIFICATION = 'pending_verification';
    const STATUS_VERIFIED = 'verified';
    const STATUS_EXECUTED = 'executed';
    const STATUS_CANCELLED = 'cancelled';

    const VERIFICATION_PENDING = 'pending';
    const VERIFICATION_APPROVED = 'approved';
    const VERIFICATION_REJECTED = 'rejected';

    const EXECUTION_PENDING = 'pending';
    const EXECUTION_COMPLETED = 'completed';
    const EXECUTION_FAILED = 'failed';

    const PAYMENT_METHOD_BANK_TRANSFER = 'bank_transfer';
    const PAYMENT_METHOD_CHECK = 'check';
    const PAYMENT_METHOD_CASH = 'cash';

    /**
     * 關聯到報銷申請單
     */
    public function financeDocument(): BelongsTo
    {
        return $this->belongsTo(FinanceDocument::class);
    }

    /**
     * 會計製單人
     */
    public function createdByAccountant(): BelongsTo
    {
        return $this->belongsTo(User::class, 'created_by_accountant_id');
    }

    /**
     * 出納覆核人
     */
    public function verifiedByCashier(): BelongsTo
    {
        return $this->belongsTo(User::class, 'verified_by_cashier_id');
    }

    /**
     * 出納執行人
     */
    public function executedByCashier(): BelongsTo
    {
        return $this->belongsTo(User::class, 'executed_by_cashier_id');
    }

    /**
     * 產生付款單號
     */
    public static function generatePaymentOrderNumber(): string
    {
        $date = now()->format('Ymd');
        $latest = self::where('payment_order_number', 'like', "PO-{$date}%")->latest('id')->first();

        if ($latest) {
            $lastNumber = (int) substr($latest->payment_order_number, -4);
            $newNumber = $lastNumber + 1;
        } else {
            $newNumber = 1;
        }

        return sprintf('PO-%s%04d', $date, $newNumber);
    }

    /**
     * 檢查是否可以被出納覆核
     */
    public function canBeVerifiedByCashier(): bool
    {
        return $this->status === self::STATUS_PENDING_VERIFICATION &&
               $this->verification_status === self::VERIFICATION_PENDING;
    }

    /**
     * 檢查是否可以執行付款
     */
    public function canBeExecuted(): bool
    {
        return $this->status === self::STATUS_VERIFIED &&
               $this->verification_status === self::VERIFICATION_APPROVED &&
               $this->execution_status === self::EXECUTION_PENDING;
    }

    /**
     * 是否已執行
     */
    public function isExecuted(): bool
    {
        return $this->status === self::STATUS_EXECUTED &&
               $this->execution_status === self::EXECUTION_COMPLETED;
    }

    /**
     * 取得付款方式文字
     */
    public function getPaymentMethodText(): string
    {
        return match ($this->payment_method) {
            self::PAYMENT_METHOD_BANK_TRANSFER => '銀行轉帳',
            self::PAYMENT_METHOD_CHECK => '支票',
            self::PAYMENT_METHOD_CASH => '現金',
            default => '未知',
        };
    }

    /**
     * 取得狀態文字
     */
    public function getStatusText(): string
    {
        return match ($this->status) {
            self::STATUS_DRAFT => '草稿',
            self::STATUS_PENDING_VERIFICATION => '待出納覆核',
            self::STATUS_VERIFIED => '已覆核',
            self::STATUS_EXECUTED => '已執行付款',
            self::STATUS_CANCELLED => '已取消',
            default => '未知',
        };
    }
}