Talaria/app/src/main/java/dev/lonami/talaria/ui/screens/ChatScreen.kt

package dev.lonami.talaria.ui.screens

import androidx.compose.foundation.layout.*
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.LazyListState
import androidx.compose.foundation.lazy.rememberLazyListState
import androidx.compose.foundation.text.KeyboardActions
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.material.Button
import androidx.compose.material.Card
import androidx.compose.material.Text
import androidx.compose.material.TextField
import androidx.compose.runtime.*
import androidx.compose.ui.Modifier
import androidx.compose.ui.res.stringResource
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.input.ImeAction
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import androidx.lifecycle.viewmodel.compose.viewModel
import dev.lonami.talaria.R
import dev.lonami.talaria.data.MockMessageRepository
import dev.lonami.talaria.ui.state.ChatViewModel
import dev.lonami.talaria.ui.theme.TalariaTheme
import kotlinx.coroutines.launch
import uniffi.talaria.Message

@Composable
fun MessageCard(message: Message, modifier: Modifier = Modifier) {
    Card(
        elevation = 4.dp,
        modifier = modifier
            .fillMaxWidth()
            .padding(8.dp)
    ) {
        Column(
            modifier = Modifier
                .fillMaxWidth()
                .padding(8.dp)
        ) {
            Text(message.sender, fontWeight = FontWeight.Bold)
            Text(message.text)
        }
    }
}

@Composable
fun MessageList(messages: List<Message>, listState: LazyListState, modifier: Modifier = Modifier) {
    LazyColumn(modifier = modifier, state = listState) {
        items(messages.size) { MessageCard(messages[it]) }
    }
}

@Composable
fun MessageInputField(
    messageText: String,
    onMessageChanged: (String) -> Unit,
    onSendMessage: () -> Unit,
    modifier: Modifier = Modifier,
) {
    Row(modifier = modifier) {
        TextField(
            messageText,
            placeholder = { Text(stringResource(R.string.write_message)) },
            keyboardOptions = KeyboardOptions(
                imeAction = ImeAction.Send
            ),
            keyboardActions = KeyboardActions(
                onDone = { onSendMessage() }
            ),
            modifier = Modifier.weight(1.0f),
            onValueChange = onMessageChanged
        )
        Button(
            onClick = onSendMessage
        ) {
            Text(stringResource(R.string.send_message))
        }
    }
}

@Composable
fun ChatScreen(
    selectedDialog: String,
    modifier: Modifier = Modifier,
    chatViewModel: ChatViewModel = viewModel(),
) {
    val chatUiState by chatViewModel.uiState.collectAsState()
    var messageText by remember { mutableStateOf("") }
    val messageListState = rememberLazyListState()
    val coroutineScope = rememberCoroutineScope()

    Column(modifier = modifier.fillMaxSize()) {
        MessageList(
            chatUiState.messages,
            modifier = Modifier.weight(1.0f),
            listState = messageListState
        )
        MessageInputField(messageText, onMessageChanged = {
            messageText = it
        }, onSendMessage = {
            chatViewModel.sendMessage(selectedDialog, messageText)
            messageText = ""
            coroutineScope.launch {
                messageListState.animateScrollToItem(chatUiState.messages.size - 1)
            }
        })
    }
}

@Preview
@Composable
fun ChatPreview() {
    val viewModel = remember { ChatViewModel(MockMessageRepository()).apply { loadMessages("") } }

    TalariaTheme {
        ChatScreen("", chatViewModel = viewModel)
    }
}