Githug-Android/app/src/main/java/solutions/tretter/githugandroid/Terminal.kt

package solutions.tretter.githugandroid

import androidx.compose.foundation.ExperimentalFoundationApi
import androidx.compose.foundation.Canvas
import androidx.compose.foundation.background
import androidx.compose.foundation.horizontalScroll
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.PaddingValues
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.RowScope
import androidx.compose.foundation.layout.fillMaxHeight
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.heightIn
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.layout.widthIn
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.foundation.text.BasicTextField
import androidx.compose.foundation.text.KeyboardActions
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.foundation.text.selection.SelectionContainer
import androidx.compose.foundation.verticalScroll
import androidx.compose.material3.Button
import androidx.compose.material3.ButtonDefaults
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.key
import androidx.compose.runtime.remember
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.focus.FocusRequester
import androidx.compose.ui.focus.focusRequester
import androidx.compose.ui.focus.onFocusChanged
import androidx.compose.ui.geometry.Rect
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.Path
import androidx.compose.ui.graphics.SolidColor
import androidx.compose.ui.layout.boundsInRoot
import androidx.compose.ui.layout.onGloballyPositioned
import androidx.compose.ui.platform.LocalConfiguration
import androidx.compose.ui.platform.LocalFocusManager
import androidx.compose.ui.platform.LocalSoftwareKeyboardController
import androidx.compose.ui.text.TextRange
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.text.font.FontFamily
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.input.ImeAction
import androidx.compose.ui.text.input.KeyboardType
import androidx.compose.ui.text.input.TextFieldValue
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp

@OptIn(ExperimentalFoundationApi::class)
@Composable
fun TerminalPane(
    output: List<String>,
    inputFieldVersion: Int,
    commandInput: TextFieldValue,
    showInputHint: Boolean,
    onInputHintDismiss: () -> Unit,
    onValueChange: (TextFieldValue) -> Unit,
    onRun: () -> Unit,
    onTab: () -> Unit,
    onHelp: () -> Unit,
    onCursorLeft: () -> Unit,
    onCursorRight: () -> Unit,
    onHistoryUp: () -> Unit,
    onHistoryDown: () -> Unit,
    onPromptBoundsChanged: (Rect) -> Unit = {},
) {
    val configuration = LocalConfiguration.current
    val focusRequester = remember { FocusRequester() }
    val focusManager = LocalFocusManager.current
    val keyboardController = LocalSoftwareKeyboardController.current
    val outputHorizontalScroll = rememberScrollState()
    val outputVerticalScroll = rememberScrollState()
    val terminalMinWidth = 80.dp * 7.2f
    val terminalPaneMaxHeight = configuration.screenHeightDp.dp * 0.7f
    val reservedControlsHeight = 86.dp
    val maxOutputHeight = (terminalPaneMaxHeight - reservedControlsHeight).coerceAtLeast(120.dp)
    val outputLineHeight = 20.dp
    val desiredOutputHeight = (output.size.coerceAtLeast(6) * outputLineHeight.value).dp.coerceAtMost(maxOutputHeight)

    LaunchedEffect(inputFieldVersion) {
        outputHorizontalScroll.scrollTo(0)
    }

    LaunchedEffect(output.size) {
        outputVerticalScroll.animateScrollTo(outputVerticalScroll.maxValue)
    }

    fun submitCommand() {
        focusManager.clearFocus(force = true)
        keyboardController?.hide()
        onRun()
    }

    fun insertLiteral(value: String) {
        val selectionStart = commandInput.selection.start.coerceIn(0, commandInput.text.length)
        val selectionEnd = commandInput.selection.end.coerceIn(0, commandInput.text.length)
        val rangeStart = minOf(selectionStart, selectionEnd)
        val rangeEnd = maxOf(selectionStart, selectionEnd)
        val newText = commandInput.text.replaceRange(rangeStart, rangeEnd, value)
        val newCursor = rangeStart + value.length
        onValueChange(TextFieldValue(newText, selection = TextRange(newCursor)))
    }

    Box(
        modifier = Modifier
            .fillMaxSize()
            .background(TerminalBackground, RoundedCornerShape(12.dp))
            .padding(8.dp)
    ) {
        Column(
            modifier = Modifier
                .fillMaxHeight()
                .widthIn(min = terminalMinWidth),
            verticalArrangement = Arrangement.spacedBy(8.dp),
        ) {
            Box(
                modifier = Modifier
                    .heightIn(min = 200.dp, max = maxOutputHeight)
                    .height(desiredOutputHeight)
                    .fillMaxWidth()
                    .background(PanelPrimary, RoundedCornerShape(10.dp))
                    .padding(8.dp)
                    .horizontalScroll(outputHorizontalScroll)
                    .verticalScroll(outputVerticalScroll),
            ) {
                SelectionContainer {
                    Column(
                        modifier = Modifier.widthIn(min = terminalMinWidth),
                        verticalArrangement = Arrangement.spacedBy(4.dp),
                    ) {
                        output.forEach { line ->
                            Text(
                                text = line,
                                color = if (line.startsWith("✔") || line.startsWith("🏁")) Success else TextSecondary,
                                fontFamily = FontFamily.Monospace,
                                softWrap = false,
                            )
                        }
                    }
                }
            }
            SpecialKeyBar(
                onTab = onTab,
                onHelp = onHelp,
                onCursorLeft = onCursorLeft,
                onCursorRight = onCursorRight,
                onHistoryUp = onHistoryUp,
                onHistoryDown = onHistoryDown,
                onInsertText = { insertLiteral(it) },
            )
            if (showInputHint) {
                TerminalInputHintBubble()
            }
            Row(
                modifier = Modifier
                    .fillMaxWidth()
                    .widthIn(min = terminalMinWidth)
                    .onGloballyPositioned { coordinates ->
                        onPromptBoundsChanged(coordinates.boundsInRoot())
                    }
                    .background(PanelPrimary, RoundedCornerShape(8.dp))
                    .padding(horizontal = 8.dp, vertical = 3.dp),
                verticalAlignment = Alignment.CenterVertically,
            ) {
                Text(
                    text = "$",
                    color = Accent,
                    fontFamily = FontFamily.Monospace,
                    fontWeight = FontWeight.Bold,
                    fontSize = 15.sp,
                )
                TerminalInputField(
                    inputFieldVersion = inputFieldVersion,
                    commandInput = commandInput,
                    onValueChange = onValueChange,
                    focusRequester = focusRequester,
                    keyboardController = keyboardController,
                    onFocused = onInputHintDismiss,
                    onSubmit = { submitCommand() },
                )
            }
        }
    }
}

@OptIn(ExperimentalFoundationApi::class)
@Composable
private fun RowScope.TerminalInputField(
    inputFieldVersion: Int,
    commandInput: TextFieldValue,
    onValueChange: (TextFieldValue) -> Unit,
    focusRequester: FocusRequester,
    keyboardController: androidx.compose.ui.platform.SoftwareKeyboardController?,
    onFocused: () -> Unit,
    onSubmit: () -> Unit,
) {
    key(inputFieldVersion) {
        BasicTextField(
            value = commandInput,
            onValueChange = onValueChange,
            modifier = Modifier
                .weight(1f)
                .focusRequester(focusRequester)
                .onFocusChanged { state ->
                    if (state.isFocused) {
                        onFocused()
                        keyboardController?.show()
                    }
                },
            singleLine = true,
            textStyle = TextStyle(
                color = TextPrimary,
                fontFamily = FontFamily.Monospace,
                fontSize = 15.sp,
                fontWeight = FontWeight.Normal,
            ),
            cursorBrush = SolidColor(Accent),
            keyboardOptions = KeyboardOptions(
                autoCorrect = false,
                keyboardType = KeyboardType.Ascii,
                imeAction = ImeAction.Done,
            ),
            keyboardActions = KeyboardActions(onDone = { onSubmit() }),
            decorationBox = { innerTextField ->
                Box(
                    modifier = Modifier
                        .fillMaxWidth()
                        .background(Color.Transparent)
                        .padding(vertical = 2.dp),
                    contentAlignment = Alignment.CenterStart,
                ) {
                    if (commandInput.text.isEmpty()) {
                        Text(
                            text = "Enter git command",
                            color = TextMuted.copy(alpha = 0.7f),
                            fontFamily = FontFamily.Monospace,
                            fontSize = 15.sp,
                        )
                    }
                    innerTextField()
                }
            },
        )
    }
}

@Composable
private fun TerminalInputHintBubble() {
    val bubbleColor = Color(0xFFFFF1A8)
    Column(
        modifier = Modifier
            .fillMaxWidth()
            .padding(start = 46.dp, end = 14.dp),
        horizontalAlignment = Alignment.Start,
    ) {
        Box(
            modifier = Modifier
                .background(bubbleColor, RoundedCornerShape(18.dp))
                .padding(horizontal = 14.dp, vertical = 10.dp),
        ) {
            Text(
                text = "Tap here to enter a command",
                color = Color(0xFF161000),
                fontFamily = FontFamily.Default,
                fontWeight = FontWeight.Bold,
                fontSize = 14.sp,
            )
        }
        Canvas(
            modifier = Modifier
                .padding(start = 26.dp)
                .width(26.dp)
                .height(13.dp),
        ) {
            drawPath(
                path = Path().apply {
                    moveTo(0f, 0f)
                    lineTo(size.width, 0f)
                    lineTo(size.width * 0.25f, size.height)
                    close()
                },
                color = bubbleColor,
            )
        }
    }
}

@Composable
private fun SpecialKeyBar(
    onTab: () -> Unit,
    onHelp: () -> Unit,
    onCursorLeft: () -> Unit,
    onCursorRight: () -> Unit,
    onHistoryUp: () -> Unit,
    onHistoryDown: () -> Unit,
    onInsertText: (String) -> Unit,
) {
    Row(
        modifier = Modifier
            .fillMaxWidth()
            .horizontalScroll(rememberScrollState()),
        horizontalArrangement = Arrangement.spacedBy(1.dp),
    ) {
        TerminalKeyButton(label = "?", onClick = onHelp, highlight = true, fontFamily = FontFamily.Default)
        TerminalKeyButton(label = "↹", onClick = onTab, fontFamily = FontFamily.Default)
        TerminalKeyButton(label = ".", onClick = { onInsertText(".") })
        TerminalKeyButton(label = "-", onClick = { onInsertText("-") })
        TerminalKeyButton(label = "/", onClick = { onInsertText("/") })
        TerminalKeyButton(label = "←", onClick = onCursorLeft)
        TerminalKeyButton(label = "→", onClick = onCursorRight)
        TerminalKeyButton(label = "↑", onClick = onHistoryUp)
        TerminalKeyButton(label = "↓", onClick = onHistoryDown)
    }
}

@Composable
private fun TerminalKeyButton(
    label: String,
    onClick: () -> Unit,
    highlight: Boolean = false,
    fontFamily: FontFamily = FontFamily.Monospace,
) {
    Button(
        onClick = onClick,
        modifier = Modifier
            .width(32.dp)
            .height(26.dp),
        shape = RoundedCornerShape(0.dp),
        contentPadding = PaddingValues(horizontal = 0.dp, vertical = 0.dp),
        colors = ButtonDefaults.buttonColors(
            containerColor = if (highlight) Color(0xFF1976D2) else PanelSecondary,
            contentColor = TextPrimary,
        ),
    ) {
        Text(
            text = label,
            fontFamily = fontFamily,
            fontWeight = FontWeight.Bold,
            fontSize = 11.sp,
        )
    }
}