<?php

namespace App\Models;

use App\User;
use Carbon\Carbon;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Collection;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\HasMany;
use Illuminate\Database\Eloquent\SoftDeletes;

/**
 * Angebots-Kopfdatensatz (Modul 6 — Offers).
 *
 * Trägt Angebotsnummer + Beziehungen zu Kontakt / Anfrage / Buchung und
 * zeigt via `current_version_id` auf die aktuell gültige OfferVersion.
 * Die eigentlichen Inhalte (Texte, Positionen, Preise, PDF) liegen in
 * `offer_versions`. Jede Änderung nach dem ersten Versand erzeugt eine
 * neue Version (siehe OfferVersion::isEditable()).
 *
 * @property int            $id
 * @property string         $offer_number
 * @property int            $contact_id
 * @property int|null       $inquiry_id
 * @property int|null       $booking_id
 * @property string         $status                   draft|sent|accepted|declined|expired|withdrawn
 * @property int|null       $current_version_id
 * @property int            $created_by
 * @property Carbon         $created_at
 * @property Carbon         $updated_at
 * @property Carbon|null    $deleted_at
 * @property-read Contact           $contact
 * @property-read Lead|null         $inquiry
 * @property-read Booking|null      $booking
 * @property-read Collection|OfferVersion[] $versions
 * @property-read OfferVersion|null $currentVersion
 * @property-read User              $createdBy
 */
class Offer extends Model
{
    use HasFactory, SoftDeletes;

    public const STATUS_DRAFT     = 'draft';
    public const STATUS_SENT      = 'sent';
    public const STATUS_ACCEPTED  = 'accepted';
    public const STATUS_DECLINED  = 'declined';
    public const STATUS_EXPIRED   = 'expired';
    public const STATUS_WITHDRAWN = 'withdrawn';

    /** Stati, die als „nicht abgeschlossen" gelten (Offer läuft noch). */
    public const OPEN_STATUSES = [
        self::STATUS_DRAFT,
        self::STATUS_SENT,
    ];

    protected $connection = 'mysql';
    protected $table = 'offers';

    protected $fillable = [
        'offer_number',
        'contact_id',
        'inquiry_id',
        'booking_id',
        'status',
        'current_version_id',
        'created_by',
    ];

    protected $casts = [
        'contact_id'         => 'int',
        'inquiry_id'         => 'int',
        'booking_id'         => 'int',
        'current_version_id' => 'int',
        'created_by'         => 'int',
    ];

    // ── Beziehungen ──────────────────────────────────────────────────────────

    public function contact(): BelongsTo
    {
        return $this->belongsTo(Contact::class, 'contact_id');
    }

    /**
     * Die Anfrage (Phase 2 heißt die Tabelle `inquiries`, das Eloquent-Model
     * ist weiterhin `Lead` — Umbenennung des Models ist eigenes Ticket).
     */
    public function inquiry(): BelongsTo
    {
        return $this->belongsTo(Lead::class, 'inquiry_id');
    }

    public function booking(): BelongsTo
    {
        return $this->belongsTo(Booking::class, 'booking_id');
    }

    public function versions(): HasMany
    {
        return $this->hasMany(OfferVersion::class, 'offer_id')->orderBy('version_no');
    }

    public function currentVersion(): BelongsTo
    {
        return $this->belongsTo(OfferVersion::class, 'current_version_id');
    }

    public function createdBy(): BelongsTo
    {
        return $this->belongsTo(User::class, 'created_by');
    }

    // ── Scopes ───────────────────────────────────────────────────────────────

    /** Nur noch nicht abgeschlossene Angebote (draft + sent). */
    public function scopeOpen(Builder $query): Builder
    {
        return $query->whereIn('status', self::OPEN_STATUSES);
    }

    public function scopeForContact(Builder $query, int $contactId): Builder
    {
        return $query->where('contact_id', $contactId);
    }

    /**
     * @param  string[]  $stati
     */
    public function scopeWithStatus(Builder $query, array $stati): Builder
    {
        return $query->whereIn('status', $stati);
    }

    // ── Hilfsmethoden ────────────────────────────────────────────────────────

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

    public function isOpen(): bool
    {
        return in_array($this->status, self::OPEN_STATUSES, true);
    }
}