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package com.fit2081.labweek2

import android.content.Intent
import android.os.Bundle
import android.widget.Toast
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.material3.Button
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.OutlinedTextField
import androidx.compose.material3.Scaffold
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.res.painterResource
import androidx.compose.ui.text.input.KeyboardType
import androidx.compose.ui.text.input.PasswordVisualTransformation
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import com.fit2081.labweek2.ui.theme.LabWeek2Theme

private const val usernameStatic: String = "yfei0011"
private const val passwordStatic: String = "student"

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContent {
            LabWeek2Theme {
                Scaffold(modifier = Modifier.fillMaxSize()) { innerPadding ->
                    LoginScreen(modifier = Modifier.padding(innerPadding))
                }
            }
        }
    }
}


/**
 * Composable function representing the login screen.
 * It includes fields for username and password, along with a login button.
 */
@Preview(showBackground = true)
@Composable
fun LoginScreen(modifier: Modifier = Modifier) {
    var username by remember { mutableStateOf("") }
    var password by remember { mutableStateOf("") }

    val context = LocalContext.current

    Surface(
        modifier = modifier.fillMaxSize(),
        color = MaterialTheme.colorScheme.background
    ) {
        Column(
            modifier = Modifier
                .fillMaxSize()
                .padding(16.dp),
            horizontalAlignment = Alignment.CenterHorizontally,
            verticalArrangement = Arrangement.Top
        ) {
            // Add image at the top
            androidx.compose.foundation.Image(
                painter = painterResource(id = R.drawable.fit2081_logo_yellow),
                contentDescription = "Fit2081 Logo",
                modifier = Modifier.size(200.dp)    // Adjust the size as needed
            )
            // Add space between logo and username
            Spacer(modifier = Modifier.height(24.dp))
            OutlinedTextField(
                value = username,
                onValueChange = { username = it },
                label = { Text("Username") },
                modifier = Modifier.fillMaxWidth()
            )
            // Add space between username and password
            Spacer(modifier = Modifier.height(16.dp))
            OutlinedTextField(
                value = password,
                // when the password is changed, we update the password variable
                onValueChange = { password = it },
                label = { Text("Password") },
                visualTransformation = PasswordVisualTransformation(),
                keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Password),
                modifier = Modifier.fillMaxWidth()
            )
            Spacer(modifier = Modifier.height(24.dp))
            Button(
                onClick = {
                    if (username == usernameStatic && password == passwordStatic) {
                        // if correct show a toast message
                        Toast.makeText(context, "Login Successful", Toast.LENGTH_SHORT).show()
                        // start the dashboard activity
                        context.startActivity(Intent(context,Dashboard::class.java))
                    } else {
                        // if incorrect show a toast message
                        Toast.makeText(context, "Login Failed", Toast.LENGTH_SHORT).show()
                    }
                }
            ) {
                Text("Login")
            }
        }
    }
}