package com.example.saludapp.ui

import androidx.compose.foundation.layout.*
import androidx.compose.material3.*
import androidx.compose.runtime.*
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.text.input.PasswordVisualTransformation
import androidx.compose.ui.unit.dp
import com.example.saludapp.data.DatabaseHelper
import kotlinx.coroutines.launch

@Composable
fun LoginScreen(onLoginSuccess: (String) -> Unit, onNavigateToRegister: () -> Unit) {
    var email by remember { mutableStateOf("") }
    var password by remember { mutableStateOf("") }
    var isLoading by remember { mutableStateOf(false) }
    var errorMessage by remember { mutableStateOf<String?>(null) }
    val scope = rememberCoroutineScope()

    Surface(
        modifier = Modifier.fillMaxSize(),
        color = MaterialTheme.colorScheme.background
    ) {
        Column(
            modifier = Modifier
                .fillMaxSize()
                .padding(24.dp),
            horizontalAlignment = Alignment.CenterHorizontally,
            verticalArrangement = Arrangement.Center
        ) {
            Text(
                text = "Iniciar Sesión",
                style = MaterialTheme.typography.headlineMedium,
                color = MaterialTheme.colorScheme.primary
            )

            Spacer(modifier = Modifier.height(32.dp))

            OutlinedTextField(
                value = email,
                onValueChange = { email = it },
                label = { Text("Usuario o Email") },
                modifier = Modifier.fillMaxWidth(),
                singleLine = true,
                enabled = !isLoading
            )

            Spacer(modifier = Modifier.height(16.dp))

            OutlinedTextField(
                value = password,
                onValueChange = { password = it },
                label = { Text("Contraseña") },
                visualTransformation = PasswordVisualTransformation(),
                modifier = Modifier.fillMaxWidth(),
                singleLine = true,
                enabled = !isLoading
            )

            if (errorMessage != null) {
                Text(
                    text = errorMessage!!,
                    color = MaterialTheme.colorScheme.error,
                    modifier = Modifier.padding(top = 16.dp)
                )
            }

            Spacer(modifier = Modifier.height(32.dp))

            Button(
                onClick = { 
                    scope.launch {
                        isLoading = true
                        errorMessage = null
                        val userName = DatabaseHelper.validateLogin(email, password)
                        isLoading = false
                        if (userName != null) {
                            onLoginSuccess(userName)
                        } else {
                            errorMessage = "Usuario o contraseña incorrectos"
                        }
                    }
                },
                modifier = Modifier
                    .fillMaxWidth()
                    .height(56.dp),
                enabled = !isLoading && email.isNotEmpty() && password.isNotEmpty()
            ) {
                if (isLoading) {
                    CircularProgressIndicator(
                        modifier = Modifier.size(24.dp),
                        color = MaterialTheme.colorScheme.onPrimary,
                        strokeWidth = 2.dp
                    )
                } else {
                    Text("Entrar")
                }
            }

            TextButton(onClick = onNavigateToRegister) {
                Text("¿No tienes cuenta? Regístrate aquí")
            }
        }
    }
}