// CalculatorApp
package com.example.calculatorapp

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.padding
import androidx.compose.material3.Button
import androidx.compose.material3.OutlinedTextField
import androidx.compose.material3.Scaffold
import androidx.compose.material3.Text
import androidx.compose.material3.TextField
import androidx.compose.runtime.Composable
import androidx.compose.runtime.MutableState
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.graphics.Color
import androidx.compose.ui.text.font.FontStyle
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import com.example.calculatorapp.ui.theme.CalculatorAppTheme

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

@Composable
fun Calculator(modifier: Modifier = Modifier) {
    var first_number by remember{ mutableStateOf("") }
    var second_number by remember{mutableStateOf("")}
    var result by remember{mutableStateOf("")}

    Column(
        verticalArrangement = Arrangement.SpaceAround,
        horizontalAlignment = Alignment.CenterHorizontally,
        modifier = Modifier
            .fillMaxSize()
            .background(Color.LightGray)
            .padding(10.dp)
    )
    {
        Text(
            text = "ANDROID CALCULATOR",
            fontSize = 30.sp,
            fontWeight = FontWeight.Bold,
            color = Color.Black,
            lineHeight = 30.sp


        )

        Text(
            text = "FIRST NUMBER",
            fontSize = 24.sp,
            color = Color.Blue,
            fontWeight = FontWeight.Bold,
            fontStyle = FontStyle.Italic

        )

        TextField(
            value = first_number,
            onValueChange = {first_number = it},
            label = {
                Text(text="Enter First Number",
                    fontSize = 20.sp
                )
            },
            modifier = Modifier
                .fillMaxWidth()
                .background(Color.White)

        )

        Text(
            text = "SECOND NUMBER",
            fontSize = 24.sp,
            color = Color.Blue,
            fontWeight = FontWeight.Bold,
            fontStyle = FontStyle.Italic

        )

        TextField(
            value = second_number,
            onValueChange = {second_number = it},
            label = {
                Text(text="Enter Second Number",
                    fontSize = 20.sp
                )
            },
            modifier = Modifier
                .fillMaxWidth()
                .background(Color.White)

        )

        Text(
            text = "RESULT",
            fontSize = 24.sp,
            color = Color.Blue,
            fontWeight = FontWeight.Bold,
            fontStyle = FontStyle.Italic

        )

        TextField(
            value = result,
            onValueChange = {result = it},
            label = {
                Text(text="Enter Result",
                    fontSize = 20.sp
                )
            },
            modifier = Modifier
                .fillMaxWidth()
                .background(Color.White)

        )

        Row(
            verticalAlignment = Alignment.CenterVertically,
            horizontalArrangement = Arrangement.SpaceAround,
            modifier = Modifier
                .fillMaxWidth()

        )
        {
            Button(
                onClick = {
                    val first = first_number.toDoubleOrNull()?:0.0
                    val second = second_number.toDoubleOrNull()?:0.0
                    result = (first + second).toString()
                }
            )
            {
                Text(
                    text = "ADD",
                    fontSize = 20.sp,
                    color = Color.Black
                )
            }

            Button(
                onClick = {
                    val first = first_number.toDoubleOrNull()?:0.0
                    val second = second_number.toDoubleOrNull()?:0.0
                    result = (first - second).toString()
                }
            )
            {
                Text(
                    text = "SUBTRACT",
                    fontSize = 20.sp,
                    color = Color.Black
                )
            }
        }


        Row(
            verticalAlignment = Alignment.CenterVertically,
            horizontalArrangement = Arrangement.SpaceAround,
            modifier = Modifier
                .fillMaxWidth()

        )
        {
            Button(
                onClick = {
                    val first = first_number.toDoubleOrNull()?:0.0
                    val second = second_number.toDoubleOrNull()?:0.0
                    result = (first * second).toString()
                }
            )
            {
                Text(
                    text = "MULTIPLY",
                    fontSize = 20.sp,
                    color = Color.Black
                )
            }

            Button(
                onClick = {
                    val first = first_number.toDoubleOrNull()?:0.0
                    val second = second_number.toDoubleOrNull()?:0.0
                    result = (first / second).toString()
                }
            )
            {
                Text(
                    text = "DIVIDE",
                    fontSize = 20.sp,
                    color = Color.Black
                )
            }
        }


    }
}

@Preview(showBackground = true)
@Composable
fun GreetingPreview() {
    CalculatorAppTheme {
        Calculator(modifier = Modifier)
    }
}