package com.simats.risenow.ui.screens

import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.*
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.foundation.verticalScroll
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.Email
import androidx.compose.material.icons.filled.Lock
import androidx.compose.material.icons.filled.Visibility
import androidx.compose.material.icons.filled.VisibilityOff
import androidx.compose.material3.*
import androidx.compose.runtime.*
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.input.KeyboardType
import androidx.compose.ui.text.input.PasswordVisualTransformation
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.compose.ui.platform.LocalContext
import android.widget.Toast
import retrofit2.Call
import retrofit2.Callback
import retrofit2.Response
import com.simats.risenow.data.remote.*
import com.simats.risenow.ui.components.*
import com.simats.risenow.ui.theme.*

@Composable
fun LoginScreen(
    onLoginSuccess: (userId: String, name: String, identity: String, statement: String) -> Unit,
    onNavigateToSignup: () -> Unit
) {
    var email by remember { mutableStateOf("") }
    var password by remember { mutableStateOf("") }
    var passwordVisible by remember { mutableStateOf(false) }
    var showForgotPassword by remember { mutableStateOf(false) }
    var isLoading by remember { mutableStateOf(false) }
    val scrollState = rememberScrollState()
    val context = LocalContext.current

    AppBackground {
        Box(
            modifier = Modifier
                .fillMaxSize()
                .padding(24.dp)
        ) {
            Column(
                modifier = Modifier
                    .fillMaxSize()
                    .verticalScroll(scrollState),
                horizontalAlignment = Alignment.CenterHorizontally,
                verticalArrangement = Arrangement.Center
            ) {
                if (!showForgotPassword) {
                    Text(
                        text = "Welcome back",
                        fontSize = 32.sp,
                        fontWeight = FontWeight.Bold,
                        color = Color.White,
                        textAlign = TextAlign.Start,
                        modifier = Modifier.fillMaxWidth()
                    )

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

                    Text(
                        text = "Continue your journey with purpose.",
                        fontSize = 18.sp,
                        color = Color.Gray,
                        textAlign = TextAlign.Start,
                        modifier = Modifier.fillMaxWidth()
                    )

                    Spacer(modifier = Modifier.height(48.dp))

                    // Email Field
                    OutlinedTextField(
                        value = email,
                        onValueChange = { email = it },
                        placeholder = { Text("Email address", color = Color.Gray.copy(alpha = 0.5f)) },
                        leadingIcon = { Icon(Icons.Filled.Email, contentDescription = null, tint = Color.Gray) },
                        modifier = Modifier.fillMaxWidth(),
                        colors = OutlinedTextFieldDefaults.colors(
                            focusedBorderColor = Color(0xFF6C63FF),
                            unfocusedBorderColor = Color.Gray.copy(alpha = 0.3f),
                            focusedContainerColor = Color.White.copy(alpha = 0.05f),
                            unfocusedContainerColor = Color.White.copy(alpha = 0.05f),
                            focusedTextColor = Color.White,
                            unfocusedTextColor = Color.White
                        ),
                        shape = RoundedCornerShape(16.dp)
                    )

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

                    // Password Field
                    OutlinedTextField(
                        value = password,
                        onValueChange = { password = it },
                        placeholder = { Text("Password", color = Color.Gray.copy(alpha = 0.5f)) },
                        leadingIcon = { Icon(Icons.Filled.Lock, contentDescription = null, tint = Color.Gray) },
                        trailingIcon = {
                            val icon = if (passwordVisible) Icons.Filled.Visibility else Icons.Filled.VisibilityOff
                            IconButton(onClick = { passwordVisible = !passwordVisible }) {
                                Icon(imageVector = icon, contentDescription = null, tint = Color.Gray)
                            }
                        },
                        visualTransformation = if (passwordVisible) androidx.compose.ui.text.input.VisualTransformation.None else PasswordVisualTransformation(),
                        modifier = Modifier.fillMaxWidth(),
                        colors = OutlinedTextFieldDefaults.colors(
                            focusedBorderColor = Color(0xFF6C63FF),
                            unfocusedBorderColor = Color.Gray.copy(alpha = 0.3f),
                            focusedContainerColor = Color.White.copy(alpha = 0.05f),
                            unfocusedContainerColor = Color.White.copy(alpha = 0.05f),
                            focusedTextColor = Color.White,
                            unfocusedTextColor = Color.White
                        ),
                        shape = RoundedCornerShape(16.dp),
                        keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Password)
                    )

                    // Forgot Password Link
                    Box(
                        modifier = Modifier
                            .fillMaxWidth()
                            .padding(top = 12.dp),
                        contentAlignment = Alignment.CenterEnd
                    ) {
                        Text(
                            text = "Forgot Password?",
                            color = Color(0xFF5B89F7),
                            fontSize = 14.sp,
                            fontWeight = FontWeight.Medium,
                            modifier = Modifier.clickable { showForgotPassword = true }
                        )
                    }

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

                    // Action Button
                    PrimaryButton(
                        text = "Log In",
                        isLoading = isLoading,
                        onClick = { 
                            if (email.isNotBlank() && password.isNotBlank()) {
                                isLoading = true
                                val request = LoginRequest(email, password)
                                RetrofitClient.instance.loginUser(request).enqueue(object : Callback<LoginResponse> {
                                    override fun onResponse(call: Call<LoginResponse>, response: Response<LoginResponse>) {
                                        isLoading = false
                                        if (response.isSuccessful && response.body() != null) {
                                            val user = response.body()!!
                                            Toast.makeText(context, "Login successful", Toast.LENGTH_SHORT).show()
                                            onLoginSuccess(
                                                user.userId.toString(),
                                                user.username,
                                                user.identity ?: "Student",
                                                user.identityStatement ?: ""
                                            )
                                        } else {
                                            Toast.makeText(context, "Invalid email or password", Toast.LENGTH_SHORT).show()
                                        }
                                    }

                                    override fun onFailure(call: Call<LoginResponse>, t: Throwable) {
                                        isLoading = false
                                        Toast.makeText(context, "Invalid email or password", Toast.LENGTH_SHORT).show()
                                    }
                                })
                            }
                        },
                        modifier = Modifier.fillMaxWidth()
                    )

                    Spacer(modifier = Modifier.height(24.dp))

                    // Toggle to Signup
                    Box(
                        modifier = Modifier.fillMaxWidth(),
                        contentAlignment = Alignment.Center
                    ) {
                        Text(
                            text = "New here? Create Account",
                            color = Color(0xFF5B89F7),
                            fontSize = 14.sp,
                            fontWeight = FontWeight.Medium,
                            modifier = Modifier.clickable { onNavigateToSignup() }
                        )
                    }

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

                    // OR Divider
                    Row(
                        modifier = Modifier.fillMaxWidth(),
                        verticalAlignment = Alignment.CenterVertically
                    ) {
                        HorizontalDivider(modifier = Modifier.weight(1f), color = GlassBorder)
                        Text(
                            text = "or",
                            color = TextSecondary,
                            modifier = Modifier.padding(horizontal = 16.dp),
                            style = MaterialTheme.typography.labelSmall
                        )
                        HorizontalDivider(modifier = Modifier.weight(1f), color = GlassBorder)
                    }

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

                    // Continue as Guest Button
                    GlassButton(
                        text = "Continue as Guest",
                        onClick = { onLoginSuccess("guest_user", "Guest", "Champion", "I am a champion of my own life.") },
                        modifier = Modifier.fillMaxWidth()
                    )

                } else {
                    PasswordResetFlow(
                        onBackToLogin = { showForgotPassword = false },
                        onComplete = {
                            showForgotPassword = false
                        }
                    )
                }
            }
        }
    }
}