Phase 2 Capstone · Shopping List

package com.mastercoding.phase2

import android.os.Bundle
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.Row
import androidx.compose.foundation.layout.consumeWindowInsets
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.imePadding
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.material3.Button
import androidx.compose.material3.Checkbox
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.OutlinedTextField
import androidx.compose.material3.Scaffold
import androidx.compose.material3.Text
import androidx.compose.material3.TextButton
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableIntStateOf
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.semantics.contentDescription
import androidx.compose.ui.semantics.semantics
import androidx.compose.ui.text.style.TextDecoration
import androidx.compose.ui.unit.dp

data class ShoppingItem(val id: Int, val name: String, val purchased: Boolean = false)

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContent {
            MaterialTheme {
                Scaffold { innerPadding ->
                    ShoppingListRoute(Modifier.padding(innerPadding).consumeWindowInsets(innerPadding))
                }
            }
        }
    }
}

@Composable
fun ShoppingListRoute(modifier: Modifier = Modifier) {
    // These records are intentionally in memory: activity recreation starts a new list.
    var items by remember { mutableStateOf(emptyList<ShoppingItem>()) }
    var draft by remember { mutableStateOf("") }
    var nextId by remember { mutableIntStateOf(1) }

    ShoppingListScreen(
        items = items,
        draft = draft,
        onDraftChange = { draft = it },
        onAdd = {
            val name = draft.trim()
            if (name.isNotEmpty()) {
                items = items + ShoppingItem(nextId, name)
                nextId += 1
                draft = ""
            }
        },
        onToggle = { id ->
            items = items.map { if (it.id == id) it.copy(purchased = !it.purchased) else it }
        },
        onDelete = { id -> items = items.filterNot { it.id == id } },
        modifier = modifier
    )
}

@Composable
fun ShoppingListScreen(
    items: List<ShoppingItem>,
    draft: String,
    onDraftChange: (String) -> Unit,
    onAdd: () -> Unit,
    onToggle: (Int) -> Unit,
    onDelete: (Int) -> Unit,
    modifier: Modifier = Modifier
) {
    // English labels are teaching text; use string resources for a localized app.
    LazyColumn(
        modifier = modifier.fillMaxSize().imePadding().padding(horizontal = 20.dp),
        verticalArrangement = Arrangement.spacedBy(12.dp)
    ) {
        item(key = "heading") {
            Column(verticalArrangement = Arrangement.spacedBy(12.dp), modifier = Modifier.padding(top = 20.dp)) {
                Text("Shopping List", style = MaterialTheme.typography.headlineLarge)
                Text("Practice adding, checking, and deleting items. This list is kept in memory.")
                OutlinedTextField(
                    value = draft,
                    onValueChange = onDraftChange,
                    label = { Text("Item name") },
                    singleLine = true,
                    modifier = Modifier.fillMaxWidth()
                )
                Button(onClick = onAdd, enabled = draft.isNotBlank()) { Text("Add item") }
                Text("${items.count { it.purchased }} of ${items.size} items purchased")
            }
        }
        if (items.isEmpty()) {
            item(key = "empty") { Text("Your list is empty. Add your first item above.") }
        }
        items(items = items, key = { it.id }) { item ->
            ShoppingItemRow(item = item, onToggle = { onToggle(item.id) }, onDelete = { onDelete(item.id) })
        }
        item(key = "footer") { Text("Activity recreation starts a fresh list.", Modifier.padding(bottom = 24.dp)) }
    }
}

@Composable
fun ShoppingItemRow(item: ShoppingItem, onToggle: () -> Unit, onDelete: () -> Unit) {
    Row(
        modifier = Modifier.fillMaxWidth(),
        verticalAlignment = Alignment.CenterVertically,
        horizontalArrangement = Arrangement.spacedBy(8.dp)
    ) {
        Checkbox(
            checked = item.purchased,
            onCheckedChange = { onToggle() },
            modifier = Modifier.semantics { contentDescription = "Purchased: ${item.name}" }
        )
        Text(
            text = item.name,
            modifier = Modifier.weight(1f),
            textDecoration = if (item.purchased) TextDecoration.LineThrough else TextDecoration.None
        )
        TextButton(
            onClick = onDelete,
            modifier = Modifier.semantics { contentDescription = "Delete ${item.name}" }
        ) { Text("Delete") }
    }
}