import React, { useState, useContext } from 'react';
import { Eye, EyeOff, Lock, LogIn, Mail } from 'lucide-react-native';
import { KeyboardAvoidingView, Platform, ScrollView, Text, TextInput, TouchableOpacity, View, Image, Alert } from 'react-native';
import { AuthContext } from '@/utils/authContext';
import api from '@/utils/api';

export default function LoginScreen() {
    const authContext = useContext(AuthContext);
    const [username, setUsername] = useState('');
    const [password, setPassword] = useState('');
    const [showPassword, setShowPassword] = useState(false);
    const [isLoading, setIsLoading] = useState(false);

    // TODO: Riscrivere funzione per migliorare leggibilità e gestione errori
    const handleLogin = async () => {
        // TODO: Implementa toast o messaggio di errore più user-friendly
        if (!username || !password) {
            Alert.alert("Attenzione", "Inserisci username e password");
            return;
        }

        setIsLoading(true);

        try {
            username.trim();
            password.trim();

            // Esegui richiesta di login
            const response = await api.post("/user/login", {
                username: username,
                password: password
            });

            const { token, user } = response.data;

            console.log("Login successo, token ricevuto.");
            console.log("Dati utente:", user);

            // Passiamo token e dati utente al context che gestirà salvataggio e redirect
            authContext.logIn(token, user);
        } catch (error: any) {
            console.error("Login Error:", error);
            let message = "Si è verificato un errore durante l'accesso.";
            
            if (error.response) {
                // Errore dal server (es. 401 Credenziali errate)
                if (error.response.status === 401) {
                    // TODO: Alert o Toast specifico per credenziali errate
                    message = "Credenziali non valide."
                } else {
                    message = `Errore Server: ${error.response.data.message || error.response.status}`;
                }
            } else if (error.request) {
                // Server non raggiungibile
                message = "Impossibile contattare il server. Controlla la connessione.";
            }

            Alert.alert("Login Fallito", message);
        } finally {
            setIsLoading(false);
        }
    };

    return (
        <View className="flex-1 bg-[#099499] h-screen overflow-hidden">
            {/* Header con Logo/Titolo */}
            <View className="h-[35%] flex-column justify-center items-center">
                <Image
                    source={require('@/assets/images/mariani-logo.png')}
                    className='h-24 w-80'
                    resizeMode="contain"
                />
            </View>

            {/* Form Container */}
            <View className="flex-1 bg-white rounded-t-[2.5rem] px-8 pt-10 shadow-xl w-full">
                <KeyboardAvoidingView
                    behavior={Platform.OS === 'ios' ? 'padding' : 'height'}
                    className="flex-1"
                >
                    <ScrollView showsVerticalScrollIndicator={false} className="h-full">
                        <View className="gap-6 flex flex-col" style={{ gap: '1.5rem' }}>
                            {/* Input Username / Email */}
                            <View>
                                <Text className="text-gray-700 text-lg font-bold mb-3 ml-1">Username o Email</Text>
                                <View className="flex-row items-center bg-gray-50 border border-gray-100 rounded-2xl h-16 px-4 flex">
                                    <Mail size={24} color="#9ca3af" />
                                    <TextInput
                                        className="flex-1 ml-4 text-gray-800 text-lg font-medium h-full w-full"
                                        placeholder="mario.rossi@esempio.com"
                                        placeholderTextColor="#9ca3af"
                                        value={username}
                                        onChangeText={setUsername}
                                        autoCapitalize="none"
                                        keyboardType="email-address"
                                    />
                                </View>
                            </View>

                            {/* Input Password */}
                            <View>
                                <Text className="text-gray-700 text-lg font-bold mb-3 ml-1">Password</Text>
                                <View className="flex-row items-center bg-gray-50 border border-gray-100 rounded-2xl h-16 px-4 flex">
                                    <Lock size={24} color="#9ca3af" />
                                    <TextInput
                                        className="flex-1 ml-4 text-gray-800 text-lg font-medium h-full w-full"
                                        placeholder="••••••••"
                                        placeholderTextColor="#9ca3af"
                                        value={password}
                                        onChangeText={setPassword}
                                        secureTextEntry={!showPassword}
                                    />
                                    <TouchableOpacity onPress={() => setShowPassword(!showPassword)}>
                                        {showPassword ? (
                                            <EyeOff size={24} color="#6b7280" />
                                        ) : (
                                            <Eye size={24} color="#6b7280" />
                                        )}
                                    </TouchableOpacity>
                                </View>
                                <TouchableOpacity className="mt-3 self-end" style={{ alignSelf: 'flex-end' }}>
                                    <Text className="text-[#099499] font-bold text-base">Password dimenticata?</Text>
                                </TouchableOpacity>
                            </View>

                            {/* Tasto Login */}
                            <TouchableOpacity
                                onPress={handleLogin}
                                activeOpacity={0.8}
                                className={`bg-[#099499] h-16 rounded-2xl flex-row justify-center items-center shadow-md mt-4 flex ${isLoading ? 'opacity-70' : ''}`}
                                disabled={isLoading}
                            >
                                <Text className="text-white text-xl font-bold mr-2">
                                    {isLoading ? 'Accesso in corso...' : 'Accedi'}
                                </Text>
                                {!isLoading && <LogIn size={24} color="white" />}
                            </TouchableOpacity>
                        </View>
                    </ScrollView>
                </KeyboardAvoidingView>
            </View>
        </View>
    );
}