/*
 * Copyright (c) 2023 New Vector Ltd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.element.android.features.messages.impl.timeline.components

import androidx.compose.foundation.ExperimentalFoundationApi
import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.interaction.MutableInteractionSource
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.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.lazy.grid.GridCells
import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
import androidx.compose.foundation.lazy.grid.items
import androidx.compose.foundation.pager.HorizontalPager
import androidx.compose.foundation.pager.rememberPagerState
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.material.ripple.rememberRipple
import androidx.compose.material3.Tab
import androidx.compose.material3.TabRow
import androidx.compose.runtime.Composable
import androidx.compose.runtime.remember
import androidx.compose.runtime.rememberCoroutineScope
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import com.vanniktech.emoji.Emoji
import com.vanniktech.emoji.google.GoogleEmojiProvider
import io.element.android.libraries.designsystem.preview.ElementPreviewDark
import io.element.android.libraries.designsystem.preview.ElementPreviewLight
import io.element.android.libraries.designsystem.theme.components.Icon
import io.element.android.libraries.designsystem.theme.components.Text
import io.element.android.libraries.theme.ElementTheme
import kotlinx.collections.immutable.ImmutableSet
import kotlinx.collections.immutable.persistentSetOf
import kotlinx.coroutines.launch

@OptIn(ExperimentalFoundationApi::class)
@Composable
fun EmojiPicker(
    onEmojiSelected: (Emoji) -> Unit,
    selectedEmojis: ImmutableSet<String>,
    modifier: Modifier = Modifier,
) {
    val coroutineScope = rememberCoroutineScope()

    val emojiProvider = remember { GoogleEmojiProvider() }
    val categories = remember { emojiProvider.categories }
    val pagerState = rememberPagerState(pageCount = { emojiProvider.categories.size })
    Column(modifier) {
        TabRow(
            selectedTabIndex = pagerState.currentPage,
        ) {
            categories.forEachIndexed { index, category ->
                Tab(
                    text = {
                        Icon(
                            resourceId = emojiProvider.getIcon(category),
                            contentDescription = category.categoryNames["en"]
                        )
                    },
                    selected = pagerState.currentPage == index,
                    onClick = {
                        coroutineScope.launch { pagerState.animateScrollToPage(index) }
                    }
                )
            }
        }

        HorizontalPager(
            state = pagerState,
            modifier = Modifier.fillMaxWidth(),
        ) { index ->
            val category = categories[index]
            LazyVerticalGrid(
                modifier = Modifier.fillMaxSize(),
                columns = GridCells.Adaptive(minSize = 40.dp),
                contentPadding = PaddingValues(vertical = 10.dp, horizontal = 16.dp),
                horizontalArrangement = Arrangement.spacedBy(8.dp),
            ) {
                items(category.emojis, key = { it.unicode }) { item ->
                    val backgroundColor = if (selectedEmojis.contains(item.unicode)) {
                        ElementTheme.colors.bgActionPrimaryRest
                    } else {
                        Color.Transparent
                    }

                    Box(
                        modifier = Modifier
                            .size(40.dp)
                            .background(backgroundColor, CircleShape)
                            .clickable(
                                enabled = true,
                                onClick = { onEmojiSelected(item) },
                                indication = rememberRipple(bounded = false, radius = 20.dp),
                                interactionSource = remember { MutableInteractionSource() }
                            ),
                        contentAlignment = Alignment.Center
                    ) {
                        Text(
                            text = item.unicode,
                            style = ElementTheme.typography.fontHeadingSmRegular,
                        )
                    }
                }
            }
        }
    }
}

@Preview
@Composable
internal fun EmojiPickerLightPreview() {
    ElementPreviewLight { ContentToPreview() }
}

@Preview
@Composable
internal fun EmojiPickerDarkPreview() {
    ElementPreviewDark { ContentToPreview() }
}

@Composable
private fun ContentToPreview() {
    EmojiPicker(
        onEmojiSelected = {},
        modifier = Modifier.fillMaxWidth(),
        selectedEmojis = persistentSetOf("😀", "😄", "😃")
    )
}
