package com.suno.android.ui.screens.songdetails

import androidx.compose.foundation.interaction.MutableInteractionSource
import androidx.compose.foundation.interaction.collectIsFocusedAsState
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.fillMaxWidth
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.text.BasicTextField
import androidx.compose.material3.Icon
import androidx.compose.material3.Text
import androidx.compose.material3.TextFieldDefaults
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
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.graphics.SolidColor
import androidx.compose.ui.res.painterResource
import androidx.compose.ui.res.stringResource
import androidx.compose.ui.text.SpanStyle
import androidx.compose.ui.text.buildAnnotatedString
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.input.OffsetMapping
import androidx.compose.ui.text.input.TextFieldValue
import androidx.compose.ui.text.input.TransformedText
import androidx.compose.ui.text.input.VisualTransformation
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import com.suno.android.common_ui.components.list_items.comments.MentionState
import com.suno.android.common_ui.theme.ExtendedTheme
import com.suno.android.common_ui.theme.SunoTheme
import com.suno.android.common_res.R as CommonResR
import com.suno.android.common_ui.R as CommonUiR

@Composable
fun SongDetailsMainInput(
    songTitle: String,
    songCaptionInputValue: TextFieldValue,
    songCaptionLimit: Int,
    captionMentions: List<MentionState> = emptyList(),
    onTitleFocused: () -> Unit,
    onTitleUnfocused: () -> Unit,
    onCaptionFocused: () -> Unit,
    onCaptionUnfocused: () -> Unit,
    onTitleChanged: (text: String) -> Unit,
    onCaptionChanged: (inputValue: TextFieldValue) -> Unit,
) {
    val titleInteractionSource = remember { MutableInteractionSource() }
    val captionInteractionSource = remember { MutableInteractionSource() }

    val isTitleInputFocused by titleInteractionSource.collectIsFocusedAsState()
    val isCaptionFocused by captionInteractionSource.collectIsFocusedAsState()

    // Used to skip initial unfocused event when view is first composed
    var hasTitleInitialized by remember { mutableStateOf(false) }
    var hasCaptionInitialized by remember { mutableStateOf(false) }

    LaunchedEffect(isTitleInputFocused) {
        if (isTitleInputFocused) {
            onTitleFocused()
        } else if (!hasTitleInitialized) {
            hasTitleInitialized = true
        } else {
            onTitleUnfocused()
        }
    }

    LaunchedEffect(isCaptionFocused) {
        if (isCaptionFocused) {
            onCaptionFocused()
        } else if (!hasCaptionInitialized) {
            hasCaptionInitialized = true
        } else {
            onCaptionUnfocused()
        }
    }

    val titleTextStyle = ExtendedTheme.typography.largeSubtitle
    val captionTextStyle = ExtendedTheme.typography.userTitle

    Column(
        modifier = Modifier.padding(horizontal = 8.dp),
        verticalArrangement = Arrangement.spacedBy(8.dp),
    ) {
        BasicTextField(
            value = songTitle,
            onValueChange = { onTitleChanged(it) },
            interactionSource = titleInteractionSource,
            singleLine = true,
            textStyle = titleTextStyle.copy(color = ExtendedTheme.colors.textPrimary),
            cursorBrush = SolidColor(ExtendedTheme.colors.sunoPink),
        ) { innerTextField ->
            TextFieldDefaults.DecorationBox(
                value = songTitle,
                innerTextField = innerTextField,
                interactionSource = titleInteractionSource,
                contentPadding = PaddingValues(0.dp),
                enabled = true,
                singleLine = false,
                visualTransformation = VisualTransformation.None,
                colors = TextFieldDefaults.colors(
                    cursorColor = ExtendedTheme.colors.sunoPink,
                    focusedTextColor = ExtendedTheme.colors.textPrimary,
                    unfocusedTextColor = ExtendedTheme.colors.textPrimary,
                    unfocusedContainerColor = Color.Transparent,
                    focusedContainerColor = Color.Transparent,
                    unfocusedIndicatorColor = Color.Transparent,
                    focusedIndicatorColor = Color.Transparent,
                ),
                suffix = {
                    if (!isTitleInputFocused) {
                        Icon(
                            painterResource(CommonUiR.drawable.pen_underlined),
                            contentDescription = null,
                            tint = ExtendedTheme.colors.foregroundInactive,
                        )
                    }
                },
            )
            if (songTitle.isEmpty()) {
                Text(
                    text = stringResource(CommonResR.string.untitled),
                    style = titleTextStyle,
                    color = ExtendedTheme.colors.foregroundInactive,
                )
            }
        }

        val mentionColor = ExtendedTheme.colors.textPrimary
        BasicTextField(
            modifier = Modifier
                .fillMaxWidth()
                .height(100.dp),
            value = songCaptionInputValue,
            onValueChange = { onCaptionChanged(it) },
            interactionSource = captionInteractionSource,
            textStyle = captionTextStyle.copy(color = ExtendedTheme.colors.textPrimary),
            cursorBrush = SolidColor(ExtendedTheme.colors.sunoPink),
            visualTransformation = { inputText ->
                val annotatedString = buildAnnotatedString {
                    append(inputText.text)

                    captionMentions.forEach { mention ->
                        if (mention.start !in 0..inputText.text.length) return@forEach
                        if (mention.end !in 0..inputText.text.length) return@forEach
                        addStyle(
                            style = SpanStyle(
                                fontWeight = FontWeight.Bold,
                                color = mentionColor,
                            ),
                            start = mention.start,
                            end = mention.end,
                        )
                    }
                }

                TransformedText(
                    text = annotatedString,
                    offsetMapping = OffsetMapping.Identity,
                )
            },
        ) { innerTextField ->
            Box(
                modifier = Modifier.fillMaxWidth(),
            ) {
                Text(
                    text = "${songCaptionInputValue.text.length}/$songCaptionLimit",
                    modifier = Modifier.align(Alignment.BottomEnd),
                    style = captionTextStyle,
                    color = if (songCaptionInputValue.text.length < songCaptionLimit) {
                        ExtendedTheme.colors.foregroundInactive
                    } else {
                        ExtendedTheme.colors.warning
                    },
                )
            }

            TextFieldDefaults.DecorationBox(
                value = songCaptionInputValue.text,
                innerTextField = innerTextField,
                interactionSource = captionInteractionSource,
                contentPadding = PaddingValues(0.dp),
                enabled = true,
                singleLine = false,
                visualTransformation = VisualTransformation.None,
                colors = TextFieldDefaults.colors(
                    cursorColor = ExtendedTheme.colors.sunoPink,
                    focusedTextColor = ExtendedTheme.colors.textSecondary,
                    unfocusedTextColor = ExtendedTheme.colors.textSecondary,
                    unfocusedContainerColor = Color.Transparent,
                    focusedContainerColor = Color.Transparent,
                    unfocusedIndicatorColor = Color.Transparent,
                    focusedIndicatorColor = Color.Transparent,
                ),
            )
            if (songCaptionInputValue.text.isEmpty()) {
                Text(
                    stringResource(CommonResR.string.song_details_input_captions_placeholder),
                    style = captionTextStyle,
                    color = ExtendedTheme.colors.foregroundInactive,
                    modifier = Modifier.padding(top = 4.dp),
                )
            }
        }
    }
}

@Preview
@Composable
private fun SongDetailsMainInput_Preview() {
    SunoTheme {
        SongDetailsMainInput(
            songTitle = "Under Neon Skies",
            songCaptionInputValue = TextFieldValue(),
            songCaptionLimit = 500,
            onTitleFocused = {},
            onCaptionFocused = {},
            onTitleChanged = {},
            onCaptionChanged = {},
            onTitleUnfocused = {},
            onCaptionUnfocused = {},
        )
    }
}