/*
Copyright 2022 The 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 { mocked } from "jest-mock";
import { EventType, MatrixClient, MatrixEvent, MsgType, RelationType } from "matrix-js-sdk/src/matrix";
import { Relations } from "matrix-js-sdk/src/models/relations";

import { Playback, PlaybackState } from "../../../src/audio/Playback";
import { PlaybackManager } from "../../../src/audio/PlaybackManager";
import { getReferenceRelationsForEvent } from "../../../src/events";
import { MediaEventHelper } from "../../../src/utils/MediaEventHelper";
import {
    VoiceBroadcastChunkEventType,
    VoiceBroadcastInfoEventType,
    VoiceBroadcastInfoState,
    VoiceBroadcastPlayback,
    VoiceBroadcastPlaybackEvent,
    VoiceBroadcastPlaybackState,
} from "../../../src/voice-broadcast";
import { mkEvent, stubClient } from "../../test-utils";
import { createTestPlayback } from "../../test-utils/audio";

jest.mock("../../../src/events/getReferenceRelationsForEvent", () => ({
    getReferenceRelationsForEvent: jest.fn(),
}));

jest.mock("../../../src/utils/MediaEventHelper", () => ({
    MediaEventHelper: jest.fn(),
}));

describe("VoiceBroadcastPlayback", () => {
    const userId = "@user:example.com";
    const roomId = "!room:example.com";
    let client: MatrixClient;
    let infoEvent: MatrixEvent;
    let playback: VoiceBroadcastPlayback;
    let onStateChanged: (state: VoiceBroadcastPlaybackState) => void;
    let chunk0Event: MatrixEvent;
    let chunk1Event: MatrixEvent;
    let chunk2Event: MatrixEvent;
    const chunk0Data = new ArrayBuffer(1);
    const chunk1Data = new ArrayBuffer(2);
    const chunk2Data = new ArrayBuffer(3);
    let chunk0Helper: MediaEventHelper;
    let chunk1Helper: MediaEventHelper;
    let chunk2Helper: MediaEventHelper;
    let chunk0Playback: Playback;
    let chunk1Playback: Playback;
    let chunk2Playback: Playback;

    const itShouldSetTheStateTo = (state: VoiceBroadcastPlaybackState) => {
        it(`should set the state to ${state}`, () => {
            expect(playback.getState()).toBe(state);
        });
    };

    const itShouldEmitAStateChangedEvent = (state: VoiceBroadcastPlaybackState) => {
        it(`should emit a ${state} state changed event`, () => {
            expect(mocked(onStateChanged)).toHaveBeenCalledWith(state);
        });
    };

    const mkChunkEvent = (sequence: number) => {
        return mkEvent({
            event: true,
            user: client.getUserId(),
            room: roomId,
            type: EventType.RoomMessage,
            content: {
                msgtype: MsgType.Audio,
                [VoiceBroadcastChunkEventType]: {
                    sequence,
                },
            },
        });
    };

    const mkChunkHelper = (data: ArrayBuffer): MediaEventHelper => {
        return {
            sourceBlob: {
                cachedValue: null,
                done: false,
                value: {
                    // @ts-ignore
                    arrayBuffer: jest.fn().mockResolvedValue(data),
                },
            },
        };
    };

    const mkInfoEvent = (state: VoiceBroadcastInfoState) => {
        return mkEvent({
            event: true,
            type: VoiceBroadcastInfoEventType,
            user: userId,
            room: roomId,
            content: {
                state,
            },
        });
    };

    const mkPlayback = () => {
        const playback = new VoiceBroadcastPlayback(infoEvent, client);
        jest.spyOn(playback, "removeAllListeners");
        playback.on(VoiceBroadcastPlaybackEvent.StateChanged, onStateChanged);
        return playback;
    };

    const setUpChunkEvents = (chunkEvents: MatrixEvent[]) => {
        const relations = new Relations(RelationType.Reference, EventType.RoomMessage, client);
        jest.spyOn(relations, "getRelations").mockReturnValue(chunkEvents);
        mocked(getReferenceRelationsForEvent).mockReturnValue(relations);
    };

    beforeAll(() => {
        client = stubClient();

        // crap event to test 0 as first sequence number
        chunk0Event = mkChunkEvent(0);
        chunk1Event = mkChunkEvent(1);
        chunk2Event = mkChunkEvent(2);

        chunk0Helper = mkChunkHelper(chunk0Data);
        chunk1Helper = mkChunkHelper(chunk1Data);
        chunk2Helper = mkChunkHelper(chunk2Data);

        chunk0Playback = createTestPlayback();
        chunk1Playback = createTestPlayback();
        chunk2Playback = createTestPlayback();

        jest.spyOn(PlaybackManager.instance, "createPlaybackInstance").mockImplementation(
            (buffer: ArrayBuffer, _waveForm?: number[]) => {
                if (buffer === chunk0Data) return chunk0Playback;
                if (buffer === chunk1Data) return chunk1Playback;
                if (buffer === chunk2Data) return chunk2Playback;
            },
        );

        mocked(MediaEventHelper).mockImplementation((event: MatrixEvent) => {
            if (event === chunk0Event) return chunk0Helper;
            if (event === chunk1Event) return chunk1Helper;
            if (event === chunk2Event) return chunk2Helper;
        });
    });

    beforeEach(() => {
        jest.clearAllMocks();
        onStateChanged = jest.fn();
    });

    describe("when there is a running voice broadcast with some chunks", () => {
        beforeEach(() => {
            infoEvent = mkInfoEvent(VoiceBroadcastInfoState.Running);
            playback = mkPlayback();
            setUpChunkEvents([chunk2Event, chunk0Event, chunk1Event]);
        });

        describe("and calling start", () => {
            beforeEach(async () => {
                await playback.start();
            });

            it("should play the last chunk", () => {
                // assert that the first chunk is being played
                expect(chunk2Playback.play).toHaveBeenCalled();
                expect(chunk1Playback.play).not.toHaveBeenCalled();
            });
        });
    });

    describe("when there is a stopped voice broadcast", () => {
        beforeEach(() => {
            infoEvent = mkInfoEvent(VoiceBroadcastInfoState.Stopped);
            playback = mkPlayback();
        });

        describe("and there is only a 0 sequence event", () => {
            beforeEach(() => {
                setUpChunkEvents([chunk0Event]);
            });

            describe("and calling start", () => {
                beforeEach(async () => {
                    await playback.start();
                });

                itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Stopped);
            });
        });

        describe("and there are some chunks", () => {
            beforeEach(() => {
                setUpChunkEvents([chunk2Event, chunk0Event, chunk1Event]);
            });

            it("should expose the info event", () => {
                expect(playback.infoEvent).toBe(infoEvent);
            });

            it("should be in state Stopped", () => {
                expect(playback.getState()).toBe(VoiceBroadcastPlaybackState.Stopped);
            });

            describe("and calling start", () => {
                beforeEach(async () => {
                    await playback.start();
                });

                itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Playing);

                it("should play the chunks beginning with the first one", () => {
                    // assert that the first chunk is being played
                    expect(chunk1Playback.play).toHaveBeenCalled();
                    expect(chunk2Playback.play).not.toHaveBeenCalled();

                    // simulate end of first chunk
                    chunk1Playback.emit(PlaybackState.Stopped);

                    // assert that the second chunk is being played
                    expect(chunk2Playback.play).toHaveBeenCalled();

                    // simulate end of second chunk
                    chunk2Playback.emit(PlaybackState.Stopped);

                    // assert that the entire playback is now in stopped state
                    expect(playback.getState()).toBe(VoiceBroadcastPlaybackState.Stopped);
                });

                describe("and calling pause", () => {
                    beforeEach(() => {
                        playback.pause();
                    });

                    itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Paused);
                    itShouldEmitAStateChangedEvent(VoiceBroadcastPlaybackState.Paused);
                });
            });

            describe("and calling toggle for the first time", () => {
                beforeEach(async () => {
                    await playback.toggle();
                });

                itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Playing);

                describe("and calling toggle a second time", () => {
                    beforeEach(async () => {
                        await playback.toggle();
                    });

                    itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Paused);

                    describe("and calling toggle a third time", () => {
                        beforeEach(async () => {
                            await playback.toggle();
                        });

                        itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Playing);
                    });
                });
            });

            describe("and calling stop", () => {
                beforeEach(() => {
                    playback.stop();
                });

                itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Stopped);

                describe("and calling toggle", () => {
                    beforeEach(async () => {
                        mocked(onStateChanged).mockReset();
                        await playback.toggle();
                    });

                    itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Playing);
                    itShouldEmitAStateChangedEvent(VoiceBroadcastPlaybackState.Playing);
                });
            });

            describe("and calling destroy", () => {
                beforeEach(() => {
                    playback.destroy();
                });

                it("should call removeAllListeners", () => {
                    expect(playback.removeAllListeners).toHaveBeenCalled();
                });
            });
        });
    });
});