import "package:flutter/material.dart";
import "package:google_fonts/google_fonts.dart";
import "../demo_identity.dart";
import "../services/api_client.dart";
import "../services/auth_service.dart";
import "../theme/ensup_colors.dart";
import "../widgets/ensup_top_bar.dart";
import "../widgets/identification_option.dart";
import "../widgets/brand_corners.dart";
import "home_screen.dart";
import "responsable_screen.dart";

/// Écran de démarrage : identification de l'étudiant (RG01/RG02).
class LoginScreen extends StatefulWidget {
  const LoginScreen({super.key});

  @override
  State<LoginScreen> createState() => _LoginScreenState();
}

class _LoginScreenState extends State<LoginScreen> {
  bool _connexionEnCours = false;

  void _ouvrirEtudiant() {
    Navigator.of(context).push(
      MaterialPageRoute(
        builder: (_) => const HomeScreen(),
        settings: const RouteSettings(name: "home"),
      ),
    );
  }

  void _ouvrirResponsable() {
    Navigator.of(context).push(
      MaterialPageRoute(
        builder: (_) => const ResponsableScreen(),
        settings: const RouteSettings(name: "responsable"),
      ),
    );
  }

  void _identifierParQr() {
    if (_connexionEnCours) return;
    if (AuthService.mode == AuthenticationMode.azure) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text(
            "L'identification QR securisee n'est pas encore configuree.",
          ),
        ),
      );
      return;
    }

    AuthService.selectDemoStudent();
    _ouvrirEtudiant();
  }

  Future<void> _connecterMicrosoft({required bool responsableDemo}) async {
    if (_connexionEnCours) return;

    setState(() => _connexionEnCours = true);
    try {
      if (AuthService.mode == AuthenticationMode.demo) {
        if (responsableDemo) {
          AuthService.selectDemoResponsable();
          _ouvrirResponsable();
        } else {
          AuthService.selectDemoStudent();
          _ouvrirEtudiant();
        }
        return;
      }

      await AuthService.signInWithMicrosoft();
      final reponse = await ApiClient.get("/auth/me");
      final roleCode = _roleCode(reponse);
      if (!mounted) return;

      switch (roleCode) {
        case "ETUDIANT":
          _ouvrirEtudiant();
        case "RESPONSABLE":
          _ouvrirResponsable();
        default:
          throw StateError("Role utilisateur non autorise.");
      }
    } catch (error) {
      if (!mounted) return;
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text(error.toString())));
    } finally {
      if (mounted) {
        setState(() => _connexionEnCours = false);
      }
    }
  }

  String _roleCode(dynamic reponse) {
    if (reponse is! Map || reponse["data"] is! Map) {
      throw StateError("Profil utilisateur invalide.");
    }

    final data = reponse["data"] as Map;
    if (data["role"] is! Map) {
      throw StateError("Role utilisateur absent.");
    }

    final role = data["role"] as Map;
    final code = role["code"];
    if (code is! String) {
      throw StateError("Role utilisateur invalide.");
    }

    return code;
  }

  @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: [
                    const EnsupTopBar(
                      brandText: "EME — Emprunt Matériel ENSUP",
                      campusTag: DemoIdentity.loginCampusTag,
                    ),
                    Expanded(
                      child: DecoratedBox(
                        decoration: const BoxDecoration(
                          gradient: LinearGradient(
                            begin: Alignment.topLeft,
                            end: Alignment.bottomRight,
                            colors: [Color(0xFFF0F6FF), Color(0xFFF8FAFC)],
                          ),
                        ),
                        child: Center(
                          child: SingleChildScrollView(
                            padding: const EdgeInsets.symmetric(
                              horizontal: 28,
                              vertical: 40,
                            ),
                            child: ConstrainedBox(
                              constraints: const BoxConstraints(maxWidth: 560),
                              child: Column(
                                mainAxisSize: MainAxisSize.min,
                                children: [
                                  Container(
                                    width: 72,
                                    height: 72,
                                    decoration: BoxDecoration(
                                      gradient: const LinearGradient(
                                        colors: [
                                          EnsupColors.blue3,
                                          EnsupColors.cyan,
                                        ],
                                      ),
                                      borderRadius: BorderRadius.circular(22),
                                      boxShadow: [
                                        BoxShadow(
                                          color: EnsupColors.blue3.withValues(
                                            alpha: 0.35,
                                          ),
                                          blurRadius: 24,
                                          offset: const Offset(0, 8),
                                        ),
                                      ],
                                    ),
                                    child: const Icon(
                                      Icons.badge_outlined,
                                      color: Colors.white,
                                      size: 34,
                                    ),
                                  ),
                                  const SizedBox(height: 20),
                                  Text(
                                    "Bienvenue sur EME",
                                    style: GoogleFonts.darkerGrotesque(
                                      fontSize: 34,
                                      fontWeight: FontWeight.w900,
                                      color: EnsupColors.text,
                                    ),
                                  ),
                                  const SizedBox(height: 8),
                                  Text(
                                    "Emprunt Matériel ENSUP · Accès réservé aux membres du groupe ENSUP",
                                    textAlign: TextAlign.center,
                                    style: GoogleFonts.titilliumWeb(
                                      fontSize: 14,
                                      color: EnsupColors.muted,
                                    ),
                                  ),
                                  const SizedBox(height: 28),
                                  IdentificationOption(
                                    icon: Icons.qr_code_2,
                                    iconColor: EnsupColors.cyan,
                                    label: "Scanner ma carte étudiante",
                                    description:
                                        "Présentez votre carte étudiante dématérialisée à la douchette ou à la tablette",
                                    onTap: _connexionEnCours
                                        ? null
                                        : _identifierParQr,
                                  ),
                                  const SizedBox(height: 12),
                                  IdentificationOption(
                                    icon: Icons.mail_outline,
                                    iconColor: EnsupColors.teal,
                                    label:
                                        "Connexion compte professionnel ENSUP",
                                    description:
                                        "Utiliser mon adresse e-mail Microsoft 365",
                                    onTap: _connexionEnCours
                                        ? null
                                        : () => _connecterMicrosoft(
                                            responsableDemo: false,
                                          ),
                                  ),
                                  const SizedBox(height: 20),
                                  Row(
                                    children: [
                                      const Expanded(
                                        child: Divider(color: EnsupColors.line),
                                      ),
                                      Padding(
                                        padding: const EdgeInsets.symmetric(
                                          horizontal: 12,
                                        ),
                                        child: Text(
                                          "ou",
                                          style: GoogleFonts.titilliumWeb(
                                            fontSize: 12,
                                            color: EnsupColors.muted,
                                          ),
                                        ),
                                      ),
                                      const Expanded(
                                        child: Divider(color: EnsupColors.line),
                                      ),
                                    ],
                                  ),
                                  const SizedBox(height: 20),
                                  SizedBox(
                                    width: double.infinity,
                                    child: OutlinedButton.icon(
                                      onPressed: _connexionEnCours
                                          ? null
                                          : () => _connecterMicrosoft(
                                              responsableDemo: true,
                                            ),
                                      icon: const Icon(
                                        Icons.person_outline,
                                        size: 16,
                                      ),
                                      label: Text(
                                        "Accès responsable matériel",
                                        style: GoogleFonts.darkerGrotesque(
                                          fontWeight: FontWeight.w700,
                                          fontSize: 15,
                                        ),
                                      ),
                                      style: OutlinedButton.styleFrom(
                                        foregroundColor: EnsupColors.text2,
                                        side: const BorderSide(
                                          color: EnsupColors.line,
                                          width: 1.5,
                                        ),
                                        padding: const EdgeInsets.symmetric(
                                          vertical: 14,
                                        ),
                                        shape: RoundedRectangleBorder(
                                          borderRadius: BorderRadius.circular(
                                            10,
                                          ),
                                        ),
                                      ),
                                    ),
                                  ),
                                ],
                              ),
                            ),
                          ),
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ),
          const Positioned.fill(child: BrandCorners()),
        ],
      ),
    );
  }
}