import "package:flutter/material.dart";
import "package:google_fonts/google_fonts.dart";
import "../demo_identity.dart";
import "../theme/ensup_colors.dart";
import "../models/emprunt_item.dart";
import "../models/anomalie_retour.dart";
import "../models/checklist_element_item.dart";
import "../services/emprunt_service.dart";
import "../widgets/ensup_top_bar.dart";
import "../widgets/brand_corners.dart";
import "../widgets/etat_checklist.dart";
import "../widgets/app_message.dart";
import "resultat_retour_screen.dart";

class ChecklistRetourScreen extends StatefulWidget {
  const ChecklistRetourScreen({super.key, required this.emprunt});

  final EmpruntItem emprunt;

  @override
  State<ChecklistRetourScreen> createState() => _ChecklistRetourScreenState();
}

class _ChecklistRetourScreenState extends State<ChecklistRetourScreen> {
  late final List<ChecklistElementItem> _checklistDepart =
      widget.emprunt.checklistDepart.isNotEmpty
      ? widget.emprunt.checklistDepart
      : (widget.emprunt.materiel.accessoires.isEmpty
            ? [
                ChecklistElementItem(
                  accessoireId: null,
                  nom: widget.emprunt.materiel.nom,
                  etat: "PRESENT",
                  quantite: 1,
                ),
              ]
            : widget.emprunt.materiel.accessoires
                  .map(
                    (nom) => ChecklistElementItem(
                      accessoireId: null,
                      nom: nom,
                      etat: "PRESENT",
                      quantite: 1,
                    ),
                  )
                  .toList());
  late final List<String> _elements = _checklistDepart
      .map((element) => element.nom)
      .toList();
  late final List<EtatChecklist> _etatsInitiales = _checklistDepart
      .map((element) => _etatDepuisApi(element.etat))
      .toList();
  late final List<EtatChecklist> _etats = List<EtatChecklist>.from(
    _etatsInitiales,
  );
  final TextEditingController _commentaireController = TextEditingController();
  bool _envoiEnCours = false;
  bool _alerteEnCours = false;
  bool _alerteEnvoyee = false;

  @override
  void dispose() {
    _commentaireController.dispose();
    super.dispose();
  }

  Future<void> _valider() async {
    setState(() => _envoiEnCours = true);

    final anomalies = <AnomalieRetour>[];
    for (var i = 0; i < _etats.length; i++) {
      if (_etats[i] != _etatsInitiales[i]) {
        anomalies.add(
          AnomalieRetour(
            element: _elements[i],
            etatRetour:
                "${_etatLabel(_etatsInitiales[i])} → ${_etatLabel(_etats[i])}",
          ),
        );
      }
    }

    try {
      final resultat = await EmpruntService.restituerEmprunt(
        empruntId: widget.emprunt.id,
        commentaireRetour: _commentaireController.text,
        elements: _elements.asMap().entries.map((entry) {
          final elementDepart = _checklistDepart[entry.key];
          return {
            if (elementDepart.accessoireId != null)
              "accessoireId": elementDepart.accessoireId,
            "nomElement": entry.value,
            "etat": _etatApi(_etats[entry.key]),
            "quantiteConstatee": _quantiteConstatee(entry.key),
          };
        }).toList(),
      );

      if (!mounted) {
        return;
      }

      final anomaliesAffichees = resultat.statut == "CLOTURE"
          ? <AnomalieRetour>[]
          : anomalies;
      Navigator.of(context).push(
        MaterialPageRoute(
          builder: (_) => ResultatRetourScreen(
            emprunt: widget.emprunt.copyWith(statut: resultat.statut),
            anomalies: anomaliesAffichees,
          ),
        ),
      );
    } catch (error) {
      if (!mounted) {
        return;
      }
      AppMessage.erreur(context, error);
    } finally {
      if (mounted) {
        setState(() => _envoiEnCours = false);
      }
    }
  }

  Future<void> _changerEtat(int index, EtatChecklist etat) async {
    setState(() => _etats[index] = etat);
    if (_alerteEnvoyee || etat == _etatsInitiales[index]) {
      return;
    }

    setState(() {
      _alerteEnvoyee = true;
      _alerteEnCours = true;
    });
    try {
      await EmpruntService.signalerTentativeRetour(
        empruntId: widget.emprunt.id,
        nomElement: _elements[index],
        etatInitial: _etatApi(_etatsInitiales[index]),
        etatDemande: _etatApi(etat),
      );
      if (!mounted) return;
      AppMessage.alerte(
        context,
        "Le responsable a été alerté de cette tentative de modification.",
        titre: "Changement signalé",
      );
    } catch (error) {
      if (!mounted) return;
      setState(() => _alerteEnvoyee = false);
      AppMessage.erreur(context, error);
    } finally {
      if (mounted) {
        setState(() => _alerteEnCours = false);
      }
    }
  }

  int _quantiteConstatee(int index) {
    if (_etats[index] == EtatChecklist.absent) {
      return 0;
    }
    final quantiteDepart = _checklistDepart[index].quantite;
    return quantiteDepart > 0 ? quantiteDepart : 1;
  }

  static EtatChecklist _etatDepuisApi(String etat) {
    return switch (etat) {
      "ABSENT" => EtatChecklist.absent,
      "DETERIORE" => EtatChecklist.deteriore,
      _ => EtatChecklist.present,
    };
  }

  String _etatApi(EtatChecklist etat) {
    switch (etat) {
      case EtatChecklist.present:
        return "PRESENT";
      case EtatChecklist.absent:
        return "ABSENT";
      case EtatChecklist.deteriore:
        return "DETERIORE";
    }
  }

  String _etatLabel(EtatChecklist etat) {
    return switch (etat) {
      EtatChecklist.present => "Présent",
      EtatChecklist.absent => "Absent",
      EtatChecklist.deteriore => "Détérioré",
    };
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: EnsupColors.soft,
      body: Stack(
        children: [
          Center(
            child: ConstrainedBox(
              constraints: const BoxConstraints(maxWidth: 1280, maxHeight: 820),
              child: Container(
                margin: const EdgeInsets.all(24),
                decoration: BoxDecoration(
                  color: Colors.white,
                  borderRadius: BorderRadius.circular(16),
                  boxShadow: [
                    BoxShadow(
                      color: EnsupColors.text.withValues(alpha: 0.14),
                      blurRadius: 60,
                      offset: const Offset(0, 18),
                    ),
                  ],
                ),
                clipBehavior: Clip.antiAlias,
                child: Column(
                  children: [
                    EnsupTopBar(
                      brandText: "Checklist de retour",
                      campusTag: DemoIdentity.campusTag,
                      userName: DemoIdentity.userName,
                      userInitials: DemoIdentity.userInitials,
                      onBack: () => Navigator.of(context).pop(),
                    ),
                    Expanded(
                      child: SingleChildScrollView(
                        padding: const EdgeInsets.symmetric(
                          horizontal: 24,
                          vertical: 26,
                        ),
                        child: LayoutBuilder(
                          builder: (context, constraints) {
                            if (constraints.maxWidth < 780) {
                              return Column(
                                crossAxisAlignment: CrossAxisAlignment.stretch,
                                children: [
                                  _colonneGauche(),
                                  const SizedBox(height: 22),
                                  _colonneDroite(),
                                ],
                              );
                            }
                            return Row(
                              crossAxisAlignment: CrossAxisAlignment.start,
                              children: [
                                Expanded(flex: 3, child: _colonneGauche()),
                                const SizedBox(width: 20),
                                Expanded(flex: 2, child: _colonneDroite()),
                              ],
                            );
                          },
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ),
          const Positioned.fill(child: BrandCorners()),
        ],
      ),
    );
  }

  Widget _colonneGauche() {
    final materiel = widget.emprunt.materiel;

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Container(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
          decoration: BoxDecoration(
            color: EnsupColors.soft,
            borderRadius: BorderRadius.circular(12),
            border: Border.all(
              color: EnsupColors.teal.withValues(alpha: 0.15),
              width: 1.5,
            ),
          ),
          child: Row(
            children: [
              Container(
                width: 38,
                height: 38,
                decoration: BoxDecoration(
                  color: EnsupColors.teal.withValues(alpha: 0.1),
                  borderRadius: BorderRadius.circular(9),
                ),
                child: Icon(materiel.icon, color: EnsupColors.teal, size: 18),
              ),
              const SizedBox(width: 12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      materiel.nom,
                      style: GoogleFonts.darkerGrotesque(
                        fontWeight: FontWeight.w800,
                        fontSize: 16,
                      ),
                    ),
                    Text(
                      "Emprunté le ${widget.emprunt.dateEmprunt}",
                      style: GoogleFonts.titilliumWeb(
                        fontSize: 12,
                        color: EnsupColors.muted,
                      ),
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
        const SizedBox(height: 16),
        ChecklistTableau(
          accessoires: _elements,
          etats: _etats,
          onChanged: _changerEtat,
        ),
      ],
    );
  }

  Widget _colonneDroite() {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        ChecklistInstructions(
          titre: "État validé au départ",
          texte:
              "La restitution reprend automatiquement l'état validé au départ : "
              "${_checklistDepart.map((element) => "${element.nom} ${_etatLabel(_etatDepuisApi(element.etat)).toLowerCase()}").join(" · ")}. "
              "Toute modification alerte immédiatement un responsable.",
        ),
        const SizedBox(height: 14),
        ChecklistCommentaire(
          controller: _commentaireController,
          hint: "Commentaire optionnel...",
        ),
        const SizedBox(height: 14),
        SizedBox(
          width: double.infinity,
          child: FilledButton.icon(
            onPressed: _envoiEnCours || _alerteEnCours ? null : _valider,
            icon: _envoiEnCours || _alerteEnCours
                ? const SizedBox(
                    width: 18,
                    height: 18,
                    child: CircularProgressIndicator(
                      strokeWidth: 2,
                      color: Colors.white,
                    ),
                  )
                : const Icon(Icons.check, size: 18),
            label: Text(
              _alerteEnCours
                  ? "Alerte en cours..."
                  : _envoiEnCours
                  ? "Enregistrement..."
                  : "Valider le retour",
              style: GoogleFonts.darkerGrotesque(
                fontWeight: FontWeight.w700,
                fontSize: 16,
              ),
            ),
            style: FilledButton.styleFrom(
              backgroundColor: EnsupColors.blue3,
              padding: const EdgeInsets.symmetric(vertical: 16),
              shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(10),
              ),
            ),
          ),
        ),
      ],
    );
  }
}