package com.example.compose_01

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.material3.Button
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Scaffold
import androidx.compose.material3.Text
import androidx.compose.material3.TextField
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateListOf
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.text.input.KeyboardType
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import com.example.compose_01.ui.theme.Compose01Theme

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContent {
            Compose01Theme {
                Scaffold(modifier = Modifier.fillMaxSize()) { innerPadding ->
                    Column {
                        Greeting(
                            name = "Android",
                            modifier = Modifier.padding(innerPadding)
                        )
                        //Counter()
                        //SimpleAdderApp()
                        TodoListApp()
                    }

                }
            }
        }
    }
}

@Composable
fun TodoListApp() {
    var newItemText by remember { mutableStateOf("") }
    val todoItems = remember { mutableStateListOf<String>() }

    Column(modifier = Modifier.padding(16.dp)) {
        Row(verticalAlignment = Alignment.CenterVertically) {
            TextField(
                value = newItemText,
                onValueChange = { newItemText = it },
                modifier = Modifier.weight(1f),
                label = { Text("Nový úkol") }
            )
            Spacer(modifier = Modifier.width(8.dp))
            Button(onClick = {
                if (newItemText.isNotBlank()) {
                    todoItems.add(newItemText)
                    newItemText = "" // Vyčistí pole po přidání
                }
            }) {
                Text("Přidat")
            }
        }
        Spacer(modifier = Modifier.height(16.dp))
        LazyColumn {
            items(todoItems) { item ->
                Text(text = "• $item", modifier = Modifier.padding(vertical = 4.dp))
            }
        }
    }
}


@Composable
fun SimpleAdderApp() {
    var number1 by remember { mutableStateOf("") }
    var number2 by remember { mutableStateOf("") }
    var sum by remember { mutableStateOf<Int?>(0) }

    Column(modifier = Modifier.padding(16.dp), horizontalAlignment = Alignment.CenterHorizontally) {
        TextField(
            value = number1,
            onValueChange = { number1 = it },
            label = { Text("První číslo") },
            keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number)
        )
        TextField(
            value = number2,
            onValueChange = { number2 = it },
            label = { Text("Druhé číslo") },
            keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number)
        )
        Spacer(modifier = Modifier.height(8.dp))
        Button(onClick = {
            // Převede text na čísla a sečte je
            sum = number1.toInt() + number2.toInt()
        }) {
            Text("Sečti")
        }
        Spacer(modifier = Modifier.height(16.dp))
        // Zobrazí výsledek, pouze pokud je platný
        Text(text = "Výsledek: $sum", style = MaterialTheme.typography.headlineMedium)

    }
}

@Composable
fun Counter() {
    var count by remember { mutableStateOf(5) } // Deklarace stavu
    Column {
        Text(text = count.toString()) // UI je svázáno se stavem
        Button(onClick = {
            count++ // Pouze změna stavu, UI se aktualizuje automaticky
        }) {
            Text("Click Me")
        }
    }
}


@Composable
fun Greeting(name: String, modifier: Modifier = Modifier) {
    Text(
        text = "Hello $name!",
        modifier = modifier
    )
}

@Preview(showBackground = true)
@Composable
fun GreetingPreview() {
    Compose01Theme {
        Greeting("Android")
    }
}