<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\HasMany;
use Illuminate\Database\Eloquent\Builder;
use Carbon\Carbon;

class Commande extends Model
{
    use SoftDeletes;

    protected $fillable = [
        'numero_commande', 'service_id', 'fournisseur_id', 'user_id', 'commune_id',
        'validateur_id', 'acheteur_id', 'objet', 'description', 'justification',
        'statut', 'priorite', 'reference_fournisseur', 'imputation_budgetaire',
        'montant_ht', 'montant_ttc',
        'date_demande', 'date_souhaitee', 'date_validation', 'date_commande',
        'date_livraison_prevue', 'date_reception', 'date_reception_complete', 'date_cloture',
        'notes', 'notes_fournisseur',
    ];

    protected $casts = [
        'montant_ht'               => 'decimal:2',
        'montant_ttc'              => 'decimal:2',
        'date_demande'             => 'date',
        'date_souhaitee'           => 'date',
        'date_validation'          => 'datetime',
        'date_commande'            => 'datetime',
        'date_livraison_prevue'    => 'date',
        'date_reception'           => 'datetime',
        'date_reception_complete'  => 'datetime',
        'date_cloture'             => 'datetime',
    ];

    // -----------------------------------------------------------------------
    // Constantes
    // -----------------------------------------------------------------------

    const STATUTS_LABELS = [
        'brouillon'             => 'Brouillon',
        'en_attente_validation' => 'En attente de validation',
        'validee'               => 'Validée',
        'commandee'             => 'Commandée',
        'partiellement_recue'   => 'Partiellement reçue',
        'recue_complete'        => 'Reçue complète',
        'cloturee'              => 'Clôturée',
        'annulee'               => 'Annulée',
    ];

    const STATUTS_COULEURS = [
        'brouillon'             => 'gray',
        'en_attente_validation' => 'yellow',
        'validee'               => 'blue',
        'commandee'             => 'indigo',
        'partiellement_recue'   => 'orange',
        'recue_complete'        => 'green',
        'cloturee'              => 'slate',
        'annulee'               => 'red',
    ];

    const PRIORITES_LABELS = [
        'normale'  => 'Normale',
        'haute'    => 'Haute',
        'urgente'  => 'Urgente',
    ];

    const STATUT_TRANSITIONS = [
        'brouillon'             => ['en_attente_validation', 'annulee'],
        'en_attente_validation' => ['validee', 'brouillon', 'annulee'],
        'validee'               => ['commandee', 'annulee'],
        'commandee'             => ['partiellement_recue', 'recue_complete', 'annulee'],
        'partiellement_recue'   => ['recue_complete', 'annulee'],
        'recue_complete'        => ['cloturee'],
        'cloturee'              => [],
        'annulee'               => [],
    ];

    // -----------------------------------------------------------------------
    // Relations
    // -----------------------------------------------------------------------

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

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

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

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

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

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

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

    public function lignes(): HasMany
    {
        return $this->hasMany(LigneCommande::class)->orderBy('ordre');
    }

    public function historique(): HasMany
    {
        return $this->hasMany(HistoriqueCommande::class)->orderBy('created_at', 'desc');
    }

    public function piecesJointes(): HasMany
    {
        return $this->hasMany(PieceJointe::class)->orderBy('created_at', 'desc');
    }

    // -----------------------------------------------------------------------
    // Scopes
    // -----------------------------------------------------------------------

    public function scopeEnCours(Builder $query): Builder
    {
        return $query->whereNotIn('statut', ['cloturee', 'annulee']);
    }

    public function scopeEnRetard(Builder $query): Builder
    {
        return $query->enCours()->whereNotNull('date_souhaitee')->where('date_souhaitee', '<', now()->toDateString());
    }

    public function scopeUrgentes(Builder $query): Builder
    {
        return $query->where('priorite', 'urgente');
    }

    public function scopeParService(Builder $query, int $serviceId): Builder
    {
        return $query->where('service_id', $serviceId);
    }

    public function scopeParStatut(Builder $query, string $statut): Builder
    {
        return $query->where('statut', $statut);
    }

    public function scopeParFournisseur(Builder $query, int $fournisseurId): Builder
    {
        return $query->where('fournisseur_id', $fournisseurId);
    }

    // -----------------------------------------------------------------------
    // Accesseurs
    // -----------------------------------------------------------------------

    public function getStatutLabelAttribute(): string
    {
        return self::STATUTS_LABELS[$this->statut] ?? $this->statut;
    }

    public function getStatutCouleurAttribute(): string
    {
        return self::STATUTS_COULEURS[$this->statut] ?? 'gray';
    }

    public function getEstEnRetardAttribute(): bool
    {
        return !in_array($this->statut, ['cloturee', 'annulee'])
            && $this->date_souhaitee !== null
            && $this->date_souhaitee->isPast();
    }

    public function getTauxReceptionAttribute(): float
    {
        $total = $this->lignes->sum(fn ($l) => (float) $l->quantite);
        if ($total <= 0) {
            return 0.0;
        }
        $recu = $this->lignes->sum(fn ($l) => (float) $l->quantite_recue);

        return round(min($recu / $total * 100, 100), 1);
    }

    // -----------------------------------------------------------------------
    // Numérotation automatique
    // -----------------------------------------------------------------------

    public static function genererNumero(): string
    {
        $annee = now()->year;
        $derniere = static::withTrashed()
            ->where('numero_commande', 'like', "CMD-IT-{$annee}-%")
            ->orderByDesc('id')
            ->value('numero_commande');

        $sequence = 1;
        if ($derniere) {
            $sequence = (int) substr($derniere, strrpos($derniere, '-') + 1) + 1;
        }

        return sprintf('CMD-IT-%d-%04d', $annee, $sequence);
    }

    // -----------------------------------------------------------------------
    // Moteur de transitions
    // -----------------------------------------------------------------------

    public function peutTransitionnerVers(string $statut): bool
    {
        return in_array($statut, self::STATUT_TRANSITIONS[$this->statut] ?? []);
    }

    public function transitionnerVers(string $statut, User $user, ?string $commentaire = null): bool
    {
        if (!$this->peutTransitionnerVers($statut)) {
            return false;
        }

        $ancienStatut = $this->statut;
        $this->statut = $statut;

        // Mettre à jour les dates et les acteurs selon le nouveau statut
        match ($statut) {
            'validee'             => $this->fill(['date_validation' => now(), 'validateur_id' => $user->id]),
            'commandee'           => $this->fill(['date_commande' => now(), 'acheteur_id' => $user->id]),
            'partiellement_recue' => $this->fill(['date_reception' => $this->date_reception ?? now()]),
            'recue_complete'      => $this->fill(['date_reception_complete' => now(), 'date_reception' => $this->date_reception ?? now()]),
            'cloturee'            => $this->fill(['date_cloture' => now()]),
            default               => null,
        };

        $this->save();

        HistoriqueCommande::create([
            'commande_id'   => $this->id,
            'user_id'       => $user->id,
            'ancien_statut' => $ancienStatut,
            'nouveau_statut' => $statut,
            'commentaire'   => $commentaire,
        ]);

        return true;
    }

    // -----------------------------------------------------------------------
    // Recalcul des montants (appelé depuis LigneCommande)
    // -----------------------------------------------------------------------

    public function recalculerMontants(): void
    {
        $this->lignes()->get()->tap(function ($lignes) {
            $ht  = $lignes->sum(fn ($l) => (float) $l->montant_ht);
            $ttc = $lignes->sum(fn ($l) => (float) $l->montant_ttc);
            $this->withoutEvents(function () use ($ht, $ttc) {
                $this->update(['montant_ht' => $ht, 'montant_ttc' => $ttc]);
            });
        });
    }
}