<?php

namespace App\Models;

use App\User;
use Carbon\Carbon;
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;

/**
 * Eine konkrete Version (Snapshot) eines Angebots.
 *
 * Alle inhaltlichen Felder (Texte, Preise, Gültigkeit, PDF-Pfad, Status,
 * Anhänge) hängen hier — nicht am Offer-Kopf. So bleiben bereits versendete
 * Versionen unveränderlich (`isEditable() === false`), während eine neue
 * Version ihre eigenen Texte/Positionen/Anhänge führt.
 *
 * @property int            $id
 * @property int            $offer_id
 * @property int            $version_no
 * @property string         $status                 draft|sent|accepted|declined|expired|superseded
 * @property Carbon|null    $valid_until
 * @property float          $total_price
 * @property string|null    $headline
 * @property string|null    $intro_text
 * @property string|null    $itinerary_text
 * @property string|null    $closing_text
 * @property int|null       $template_id
 * @property string|null    $pdf_path
 * @property bool           $pdf_archived
 * @property Carbon|null    $sent_at
 * @property Carbon|null    $accepted_at
 * @property string|null    $accepted_via           customer_link|admin|email
 * @property array|null     $template_document_ids  JSON-Array von zentral hinterlegten Dokument-IDs
 * @property int            $created_by
 * @property Carbon         $created_at
 * @property Carbon         $updated_at
 * @property-read Offer                    $offer
 * @property-read Collection|OfferItem[]   $items
 * @property-read Collection|OfferFile[]   $files
 * @property-read Collection|OfferAccessToken[] $tokens
 * @property-read OfferTemplate|null       $template
 * @property-read User                     $createdBy
 */
class OfferVersion extends Model
{
    use HasFactory;

    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    public const STATUS_SUPERSEDED = 'superseded';

    public const ACCEPTED_VIA_LINK  = 'customer_link';
    public const ACCEPTED_VIA_ADMIN = 'admin';
    public const ACCEPTED_VIA_EMAIL = 'email';

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

    protected $fillable = [
        'offer_id',
        'version_no',
        'status',
        'valid_until',
        'total_price',
        'headline',
        'intro_text',
        'itinerary_text',
        'closing_text',
        'template_id',
        'pdf_path',
        'pdf_archived',
        'sent_at',
        'accepted_at',
        'accepted_via',
        'template_document_ids',
        'created_by',
    ];

    protected $casts = [
        'offer_id'              => 'int',
        'version_no'            => 'int',
        'template_id'           => 'int',
        'created_by'            => 'int',
        'total_price'           => 'decimal:2',
        'valid_until'           => 'date',
        'sent_at'               => 'datetime',
        'accepted_at'           => 'datetime',
        'pdf_archived'          => 'bool',
        'template_document_ids' => 'array',
    ];

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

    public function offer(): BelongsTo
    {
        return $this->belongsTo(Offer::class, 'offer_id');
    }

    public function items(): HasMany
    {
        return $this->hasMany(OfferItem::class, 'offer_version_id')->orderBy('position');
    }

    public function files(): HasMany
    {
        return $this->hasMany(OfferFile::class, 'offer_version_id');
    }

    public function tokens(): HasMany
    {
        return $this->hasMany(OfferAccessToken::class, 'offer_version_id');
    }

    public function template(): BelongsTo
    {
        return $this->belongsTo(OfferTemplate::class, 'template_id');
    }

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

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

    /**
     * Darf diese Version noch bearbeitet werden?
     * Nur Draft-Versionen sind editierbar; alle anderen sind eingefroren.
     */
    public function isEditable(): bool
    {
        return $this->status === self::STATUS_DRAFT;
    }

    /**
     * Liefert den zuletzt erzeugten, noch nicht widerrufenen Token
     * (falls vorhanden) — wird im Freigabe-Link verwendet.
     */
    public function latestToken(): ?OfferAccessToken
    {
        return $this->tokens()
            ->whereNull('revoked_at')
            ->orderByDesc('id')
            ->first();
    }

    /**
     * Formatierter Preis („1.234,56 €"), konsistent mit der Darstellung
     * im Buchungsdetail.
     */
    public function totalPriceFormatted(): string
    {
        return number_format((float) $this->total_price, 2, ',', '.') . ' €';
    }

    /**
     * Gibt die URL auf das zuletzt erzeugte PDF dieser Version zurück,
     * oder null, wenn noch kein PDF existiert.
     */
    public function getPdfUrl(bool $download = false): ?string
    {
        if (! $this->pdf_path) {
            return null;
        }
        return route('offer_pdf', ['versionId' => $this->id, 'do' => $download ? 'download' : null]);
    }
}