/*
 * Copyright 2023-2024 LiveKit, Inc.
 *
 * 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.livekit.android.composesample.ui

import androidx.compose.foundation.background
import androidx.compose.foundation.gestures.detectTransformGestures
import androidx.compose.foundation.layout.Box
import androidx.compose.runtime.Composable
import androidx.compose.runtime.DisposableEffect
import androidx.compose.runtime.currentCompositeKeyHash
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.input.pointer.pointerInput
import androidx.compose.ui.layout.onGloballyPositioned
import androidx.compose.ui.platform.LocalView
import androidx.compose.ui.viewinterop.AndroidView
import io.livekit.android.camerax.ui.ScaleZoomHelper
import io.livekit.android.renderer.TextureViewRenderer
import io.livekit.android.room.Room
import io.livekit.android.room.track.LocalVideoTrack
import io.livekit.android.room.track.RemoteVideoTrack
import io.livekit.android.room.track.VideoTrack
import livekit.org.webrtc.RendererCommon

enum class ScaleType {
    FitInside,
    Fill,
}

/**
 * Widget for displaying a VideoTrack. Handles the Compose <-> AndroidView interop needed to use
 * [TextureViewRenderer].
 */
@Composable
fun VideoRenderer(
    room: Room,
    videoTrack: VideoTrack?,
    modifier: Modifier = Modifier,
    mirror: Boolean = false,
    scaleType: ScaleType = ScaleType.Fill,
) {
    // Show a black box for preview.
    if (LocalView.current.isInEditMode) {
        Box(
            modifier = Modifier
                .background(Color.Black)
                .then(modifier)
        )
        return
    }

    val scaleZoomHelper = remember(room, videoTrack) {
        if (videoTrack is LocalVideoTrack) {
            ScaleZoomHelper(videoTrack)
        } else {
            null
        }
    }
    val videoSinkVisibility = remember(room, videoTrack) { ComposeVisibility() }
    var boundVideoTrack by remember { mutableStateOf<VideoTrack?>(null) }
    var view: TextureViewRenderer? by remember { mutableStateOf(null) }

    fun cleanupVideoTrack() {
        view?.let { boundVideoTrack?.removeRenderer(it) }
        boundVideoTrack = null
    }

    fun setupVideoIfNeeded(videoTrack: VideoTrack?, view: TextureViewRenderer) {
        if (boundVideoTrack == videoTrack) {
            return
        }

        cleanupVideoTrack()

        boundVideoTrack = videoTrack
        if (videoTrack != null) {
            if (videoTrack is RemoteVideoTrack) {
                videoTrack.addRenderer(view, videoSinkVisibility)
            } else {
                videoTrack.addRenderer(view)
            }
        }
    }

    DisposableEffect(view, mirror) {
        view?.setMirror(mirror)
        onDispose { }
    }

    DisposableEffect(room, videoTrack) {
        onDispose {
            videoSinkVisibility.onDispose()
            cleanupVideoTrack()
        }
    }

    DisposableEffect(currentCompositeKeyHash.toString()) {
        onDispose {
            view?.release()
        }
    }

    AndroidView(
        factory = { context ->
            TextureViewRenderer(context).apply {
                room.initVideoRenderer(this)
                setupVideoIfNeeded(videoTrack, this)

                when (scaleType) {
                    ScaleType.FitInside -> {
                        this.setScalingType(RendererCommon.ScalingType.SCALE_ASPECT_FIT)
                    }

                    ScaleType.Fill -> {
                        this.setScalingType(RendererCommon.ScalingType.SCALE_ASPECT_FILL)
                    }
                }
                view = this
            }
        },
        update = { v -> setupVideoIfNeeded(videoTrack, v) },
        modifier = modifier
            .onGloballyPositioned { videoSinkVisibility.onGloballyPositioned(it) }
            .pointerInput(Unit) {
                detectTransformGestures(
                    onGesture = { _, _, zoom, _ ->
                        scaleZoomHelper?.zoom(zoom)
                    },
                )
            },
    )
}