<?php

declare(strict_types=1);

namespace App\Models;

use App\Enums\InvoiceStatus;
use Illuminate\Database\Eloquent\Factories\HasFactory;
// InvoiceSettings used for number generation
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\HasMany;
use Illuminate\Database\Eloquent\SoftDeletes;

class Invoice extends Model
{
    use HasFactory, SoftDeletes;

    protected $fillable = [
        'client_id', 'invoice_number', 'title', 'description',
        'subtotal', 'tax_rate', 'tax_amount', 'total', 'currency',
        'status', 'issue_date', 'due_date', 'paid_date', 'notes',
        'bank_name', 'bank_account', 'bank_holder', 'branch_name',
        'signature_image', 'signer_name', 'signer_title', 'discount_rate',
    ];

    protected $casts = [
        'status'     => InvoiceStatus::class,
        'issue_date' => 'date',
        'due_date'   => 'date',
        'paid_date'  => 'date',
        'subtotal'   => 'decimal:2',
        'tax_rate'   => 'decimal:2',
        'tax_amount' => 'decimal:2',
        'total'      => 'decimal:2',
    ];

    public function client(): BelongsTo
    {
        return $this->belongsTo(Client::class);
    }

    public function items(): HasMany
    {
        return $this->hasMany(InvoiceItem::class);
    }

    public function recalculate(): void
    {
        // Total of all items
        $this->subtotal = $this->items->sum('total');

        $discountAmount = 0;
        if ($this->discount_rate > 0) {
            $discountableSubtotal = $this->items->where('is_discountable', true)->sum('total');
            $discountAmount = round((float) $discountableSubtotal * ($this->discount_rate / 100), 2);
        }

        $this->subtotal = $this->subtotal - $discountAmount;

        // Tax is calculated only on taxable items
        $taxableSubtotal = 0;
        foreach ($this->items as $item) {
            if ($item->is_taxable) {
                if ($this->discount_rate > 0 && $item->is_discountable) {
                    $taxableSubtotal += $item->total * (1 - $this->discount_rate / 100);
                } else {
                    $taxableSubtotal += $item->total;
                }
            }
        }

        $this->tax_amount = round((float) $taxableSubtotal * ($this->tax_rate / 100), 2);

        // Grand total = subtotal (tax is borne by client separately)
        $this->total = $this->subtotal;
        $this->save();
    }

    public function getFormattedTotalAttribute(): string
    {
        return 'Rp ' . number_format((float) $this->total, 0, ',', '.');
    }

    public function getDiscountAmountAttribute(): float
    {
        if ($this->discount_rate <= 0) return 0.0;
        
        $discountableSubtotal = $this->items->where('is_discountable', true)->sum('total');
        return round((float) $discountableSubtotal * ($this->discount_rate / 100), 2);
    }

    public static function generateNumber(): string
    {
        return InvoiceSettings::generateNumber();
    }
}