/*
Copyright 2022 Matrix.org Foundation C.I.C.

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.
*/

import React, {
  useState,
  useEffect,
  useCallback,
  useMemo,
  useContext,
  createContext,
} from "react";

const MediaHandlerContext = createContext();

function getMediaPreferences() {
  const mediaPreferences = localStorage.getItem("matrix-media-preferences");

  if (mediaPreferences) {
    try {
      return JSON.parse(mediaPreferences);
    } catch (e) {
      return undefined;
    }
  } else {
    return undefined;
  }
}

function updateMediaPreferences(newPreferences) {
  const oldPreferences = getMediaPreferences(newPreferences);

  localStorage.setItem(
    "matrix-media-preferences",
    JSON.stringify({
      ...oldPreferences,
      ...newPreferences,
    })
  );
}

export function MediaHandlerProvider({ client, children }) {
  const [
    {
      audioInput,
      videoInput,
      audioInputs,
      videoInputs,
      audioOutput,
      audioOutputs,
    },
    setState,
  ] = useState(() => {
    const mediaPreferences = getMediaPreferences();
    const mediaHandler = client.getMediaHandler();

    mediaHandler.restoreMediaSettings(
      mediaPreferences?.audioInput,
      mediaPreferences?.videoInput
    );

    return {
      audioInput: mediaHandler.audioInput,
      videoInput: mediaHandler.videoInput,
      audioOutput: undefined,
      audioInputs: [],
      videoInputs: [],
      audioOutputs: [],
    };
  });

  useEffect(() => {
    const mediaHandler = client.getMediaHandler();

    function updateDevices() {
      navigator.mediaDevices.enumerateDevices().then((devices) => {
        const mediaPreferences = getMediaPreferences();

        const audioInputs = devices.filter(
          (device) => device.kind === "audioinput"
        );
        const audioConnected = audioInputs.some(
          (device) => device.deviceId === mediaHandler.audioInput
        );

        let audioInput = mediaHandler.audioInput;

        if (!audioConnected && audioInputs.length > 0) {
          audioInput = audioInputs[0].deviceId;
        }

        const videoInputs = devices.filter(
          (device) => device.kind === "videoinput"
        );
        const videoConnected = videoInputs.some(
          (device) => device.deviceId === mediaHandler.videoInput
        );

        let videoInput = mediaHandler.videoInput;

        if (!videoConnected && videoInputs.length > 0) {
          videoInput = videoInputs[0].deviceId;
        }

        const audioOutputs = devices.filter(
          (device) => device.kind === "audiooutput"
        );
        let audioOutput = undefined;

        if (
          mediaPreferences &&
          audioOutputs.some(
            (device) => device.deviceId === mediaPreferences.audioOutput
          )
        ) {
          audioOutput = mediaPreferences.audioOutput;
        }

        if (
          mediaHandler.videoInput !== videoInput ||
          mediaHandler.audioInput !== audioInput
        ) {
          mediaHandler.setMediaInputs(audioInput, videoInput);
        }

        updateMediaPreferences({ audioInput, videoInput, audioOutput });

        setState({
          audioInput,
          videoInput,
          audioOutput,
          audioInputs,
          videoInputs,
          audioOutputs,
        });
      });
    }
    updateDevices();

    mediaHandler.on("local_streams_changed", updateDevices);
    navigator.mediaDevices.addEventListener("devicechange", updateDevices);

    return () => {
      mediaHandler.removeListener("local_streams_changed", updateDevices);
      navigator.mediaDevices.removeEventListener("devicechange", updateDevices);
      mediaHandler.stopAllStreams();
    };
  }, [client]);

  const setAudioInput = useCallback(
    (deviceId) => {
      updateMediaPreferences({ audioInput: deviceId });
      setState((prevState) => ({ ...prevState, audioInput: deviceId }));
      client.getMediaHandler().setAudioInput(deviceId);
    },
    [client]
  );

  const setVideoInput = useCallback(
    (deviceId) => {
      updateMediaPreferences({ videoInput: deviceId });
      setState((prevState) => ({ ...prevState, videoInput: deviceId }));
      client.getMediaHandler().setVideoInput(deviceId);
    },
    [client]
  );

  const setAudioOutput = useCallback((deviceId) => {
    updateMediaPreferences({ audioOutput: deviceId });
    setState((prevState) => ({ ...prevState, audioOutput: deviceId }));
  }, []);

  const context = useMemo(
    () => ({
      audioInput,
      audioInputs,
      setAudioInput,
      videoInput,
      videoInputs,
      setVideoInput,
      audioOutput,
      audioOutputs,
      setAudioOutput,
    }),
    [
      audioInput,
      audioInputs,
      setAudioInput,
      videoInput,
      videoInputs,
      setVideoInput,
      audioOutput,
      audioOutputs,
      setAudioOutput,
    ]
  );

  return (
    <MediaHandlerContext.Provider value={context}>
      {children}
    </MediaHandlerContext.Provider>
  );
}

export function useMediaHandler() {
  return useContext(MediaHandlerContext);
}
