<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;
use Illuminate\Support\Str;

class Page extends Model
{
    use HasFactory, SoftDeletes;

    const STATUS_DRAFT = 'draft';

    const STATUS_PUBLISHED = 'published';

    protected $fillable = [
        'title',
        'slug',
        'content',
        'template',
        'custom_fields',
        'status',
        'meta_description',
        'meta_keywords',
        'parent_id',
        'sort_order',
        'published_at',
        'created_by_user_id',
        'last_updated_by_user_id',
    ];

    protected $casts = [
        'custom_fields' => 'array',
        'meta_keywords' => 'array',
        'sort_order' => 'integer',
        'published_at' => 'datetime',
    ];

    protected static function boot()
    {
        parent::boot();

        static::creating(function (Page $page) {
            if (empty($page->slug)) {
                $slug = Str::slug($page->title);
                if (empty($slug)) {
                    $slug = 'page-'.time();
                }
                $originalSlug = $slug;
                $count = 1;
                while (static::withTrashed()->where('slug', $slug)->exists()) {
                    $slug = $originalSlug.'-'.$count++;
                }
                $page->slug = $slug;
            }
        });
    }

    // ==================== Relationships ====================

    public function parent()
    {
        return $this->belongsTo(Page::class, 'parent_id');
    }

    public function children()
    {
        return $this->hasMany(Page::class, 'parent_id')->orderBy('sort_order');
    }

    public function creator()
    {
        return $this->belongsTo(User::class, 'created_by_user_id');
    }

    public function lastUpdatedBy()
    {
        return $this->belongsTo(User::class, 'last_updated_by_user_id');
    }

    // ==================== Query Scopes ====================

    public function scopePublished(Builder $query): Builder
    {
        return $query->where('status', self::STATUS_PUBLISHED);
    }

    public function scopeTopLevel(Builder $query): Builder
    {
        return $query->whereNull('parent_id');
    }

    // ==================== Helper Methods ====================

    public function isDraft(): bool
    {
        return $this->status === self::STATUS_DRAFT;
    }

    public function isPublished(): bool
    {
        return $this->status === self::STATUS_PUBLISHED;
    }

    public function publish(?User $user = null): void
    {
        $updates = [
            'status' => self::STATUS_PUBLISHED,
            'published_at' => $this->published_at ?? now(),
        ];

        if ($user) {
            $updates['last_updated_by_user_id'] = $user->id;
        }

        $this->update($updates);
    }

    public function getStatusLabel(): string
    {
        return match ($this->status) {
            self::STATUS_DRAFT => '草稿',
            self::STATUS_PUBLISHED => '已發布',
            default => '未知',
        };
    }
}