<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Concerns\HasUuids;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\HasManyThrough;

class Contract extends Model
{
    use HasUuids, HasFactory;

    protected $guarded = [];

    private static bool $calculating = false;

    protected $casts = [
        'metadata' => 'array',
        'discount_details' => 'array',
        'calculation_log' => 'array',
        'total_value' => 'decimal:2',
        'land_value' => 'decimal:2',
        'foundation_value' => 'decimal:2',
        'total_value_with_foundation' => 'decimal:2',
        'paid_amount' => 'decimal:2',
        'remaining_amount' => 'decimal:2',
        'excess_amount' => 'decimal:2',
        'signing_date' => 'date',
        'sale_date' => 'date',
        'hql_confirmation_date' => 'date',
    ];

    public function product()
    {
        return $this->belongsTo(Product::class);
    }

    public function paymentTemplate()
    {
        return $this->belongsTo(PaymentTemplate::class);
    }

    public function customers()
    {
        return $this->belongsToMany(Customer::class, 'contract_customers')
                    ->using(ContractCustomer::class)
                    ->withPivot('id', 'role', 'transfer_order')
                    ->withTimestamps();
    }

    public function appendices()
    {
        return $this->hasMany(Appendix::class);
    }

    public function paymentSchedule()
    {
        return $this->hasOne(PaymentSchedule::class);
    }

    public function scheduleItems(): HasManyThrough
    {
        return $this->hasManyThrough(
            PaymentScheduleItem::class,
            PaymentSchedule::class,
            'contract_id',
            'schedule_id',
            'id',
            'id'
        );
    }

    public function payments()
    {
        return $this->hasMany(Payment::class);
    }

    public function paymentFines()
    {
        return $this->hasMany(PaymentFine::class);
    }

    /**
     * Giá trị sau chiết khấu (qua PriceCalculationService).
     */
    public function getFinalValueAttribute(): float
    {
        if ($this->calculation_log) {
            return (float) ($this->calculation_log['final_values']['total_payment'] ?? 0);
        }

        // Fallback: tính nhanh nếu chưa có calculation_log
        $result = \App\Services\Calculation\PriceCalculationService::calculateForContract($this);
        return (float) ($result->get('total_payment') ?? 0);
    }

    /**
     * Lấy phiếu tính giá chi tiết.
     */
    public function getPriceSheetAttribute(): ?array
    {
        if ($this->calculation_log) {
            return $this->calculation_log['price_sheet'] ?? null;
        }
        return null;
    }

    protected static function booted()
    {
        static::saving(function ($contract) {
            // Bảo vệ tính toán tài chính: total_value luôn bằng land_value + foundation_value
            $landValue = (float) ($contract->land_value ?? 0);
            $foundationValue = (float) ($contract->foundation_value ?? 0);

            if ($landValue > 0 || $foundationValue > 0) {
                $contract->total_value = $landValue + $foundationValue;
            } elseif ($contract->exists === false && empty($contract->total_value) && !empty($contract->product_id)) {
                // Fallback khi tạo mới và chưa có giá trị tài chính chi tiết
                $product = Product::find($contract->product_id);
                if ($product) {
                    $contract->total_value = $product->total_price;
                }
            }

            $contract->remaining_amount = (float) ($contract->total_value ?? 0) - (float) ($contract->paid_amount ?? 0);
        });

        static::saved(function ($contract) {
            // Guard: tránh infinite loop khi lưu calculation_log
            if (self::$calculating) return;
            
            // Tự động tính toán và lưu snapshot sau khi lưu
            if ($contract->land_value || $contract->foundation_value) {
                self::$calculating = true;
                
                try {
                    $result = \App\Services\Calculation\PriceCalculationService::calculateForContract($contract);
                    $contract->updateQuietly([
                        'calculation_log' => [
                            'steps' => $result->getSteps(),
                            'final_values' => $result->getValues(),
                            'price_sheet' => $result->toPriceSheet(),
                            'calculated_at' => now()->toDateTimeString(),
                        ],
                    ]);
                } finally {
                    self::$calculating = false;
                }
            }
        });
    }
}