//
//  ActiveSpeakerDetectorTests.swift
//  AmazonChimeSDK
//
//  Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
//  SPDX-License-Identifier: Apache-2.0
//

import Foundation

@testable import AmazonChimeSDK
import XCTest

class ActiveSpeakerDetectorTests: XCTestCase, ActiveSpeakerPolicy, ActiveSpeakerObserver {
    let scores = [0.1, 0.2, 0.3, 0.4, 0.5]
    let volumes: [VolumeLevel] = [.muted, .notSpeaking, .low, .medium, .high]
    var attendees = [AttendeeInfo]()
    var volumeUpdates = [VolumeUpdate]()
    var attendeesReceived: [AttendeeInfo] = [AttendeeInfo(attendeeId: "", externalUserId: "")]
    var scoreChangeAttendees: [AttendeeInfo: Double] = [AttendeeInfo(attendeeId: "", externalUserId: ""): 0.0]
    var scoreIndex = 0
    var activeSpeakerDetector = DefaultActiveSpeakerDetector(selfAttendeeId: "")

    private let emptyAttendeesReceivedExpectation = XCTestExpectation(
        description: "Is fulfilled when received no attendees in callback")
    private let calculateScoreExpectation = XCTestExpectation(
        description: "Is fulfilled when calculateScore is called")
    private let prioritizeBandwidthExpectation = XCTestExpectation(
        description: "Is fulfilled when prioritizeVideoSendBandwidthForActiveSpeaker is called")
    private let activeSpeakerDidDetectExpectation = XCTestExpectation(
        description: "Is fulfilled when activeSpeakerDidDetect is called")
    private let activeSpeakerScoreDidChangeExpectation = XCTestExpectation(
        description: "Is fulfilled when activeSpeakerScoreDidChange is called")
    private let oneMilliSecondInSeconds = 0.001
    private let twoHundredMilliSecondsInSeconds = 0.2
    private let halfSeconds = 0.5

    override func setUp() {
        for index in 0 ... 4 {
            attendees.append(AttendeeInfo(
                attendeeId: "attendee" + String(index),
                externalUserId: "attendee" + String(index)
            ))
            volumeUpdates.append(VolumeUpdate(attendeeInfo: attendees[index], volumeLevel: volumes[index]))
        }
        calculateScoreExpectation.expectedFulfillmentCount = 5
        prioritizeBandwidthExpectation.assertForOverFulfill = true
        activeSpeakerDetector = DefaultActiveSpeakerDetector(selfAttendeeId: "attendee0")
        activeSpeakerDetector.addActiveSpeakerObserver(policy: self, observer: self)
        activeSpeakerDetector.attendeesDidJoin(attendeeInfo: attendees)
    }

    override func tearDown() {
        activeSpeakerDetector.removeActiveSpeakerObserver(observer: self)
    }

    func testActiveSpeakerDetectorShouldOnAttendeesJoinMakeExpectedCallbacks() {
        // received no attendees in callback because scores are not calculated until volumes are received
        wait(for: [emptyAttendeesReceivedExpectation], timeout: oneMilliSecondInSeconds)
        XCTAssertEqual(attendeesReceived.isEmpty, true)
        calculateScoreExpectation.isInverted = true
        wait(for: [calculateScoreExpectation], timeout: oneMilliSecondInSeconds)
        prioritizeBandwidthExpectation.isInverted = true
        wait(for: [prioritizeBandwidthExpectation], timeout: oneMilliSecondInSeconds)
        wait(for: [activeSpeakerDidDetectExpectation], timeout: oneMilliSecondInSeconds)
    }

    func testActiveSpeakerDetectorShouldOnVolumeChangeMakeExpectedCallbacks() {
        activeSpeakerDetector.volumeDidChange(volumeUpdates: volumeUpdates)
        calculateScoreExpectation.expectedFulfillmentCount = 2
        wait(for: [calculateScoreExpectation], timeout: twoHundredMilliSecondsInSeconds)
        wait(for: [prioritizeBandwidthExpectation], timeout: oneMilliSecondInSeconds)
        wait(for: [activeSpeakerDidDetectExpectation], timeout: oneMilliSecondInSeconds)
        XCTAssertEqual(attendeesReceived, attendees.reversed())
    }

    func testActiveSpeakerDetectorMakesScoresCallback() {
        activeSpeakerDetector.volumeDidChange(volumeUpdates: volumeUpdates)
        wait(for: [activeSpeakerScoreDidChangeExpectation], timeout: TimeInterval(scoresCallbackIntervalMs))
        XCTAssertEqual(scoreChangeAttendees.map { $0.key }.sorted(), attendees.sorted())
    }

    func testActiveSpeakerDetectorShouldOnAttendeesLeaveReceiveCorrectActiveSpeakers() {
        activeSpeakerDetector.volumeDidChange(volumeUpdates: volumeUpdates)
        wait(for: [activeSpeakerScoreDidChangeExpectation], timeout: twoHundredMilliSecondsInSeconds)
        XCTAssertEqual(attendeesReceived, attendees.reversed())

        activeSpeakerDetector.attendeesDidLeave(attendeeInfo: [attendees[0], attendees[1]])
        let newVolumeUpdates = [volumeUpdates[2], volumeUpdates[3], volumeUpdates[4]]
        scoreIndex = 0
        activeSpeakerDetector.volumeDidChange(volumeUpdates: newVolumeUpdates)
        let adhocWaitingExpectation = XCTestExpectation(description: "Is fulfilled after adhoc waiting")
        Timer.scheduledTimer(withTimeInterval: twoHundredMilliSecondsInSeconds, repeats: false, block: { _ in
            adhocWaitingExpectation.fulfill()
        })
        wait(for: [adhocWaitingExpectation], timeout: halfSeconds)
        XCTAssertEqual(attendeesReceived, [attendees[4], attendees[3], attendees[2]])
    }

    func testActiveSpeakerDetectorShouldRemoveActiveSpeakerObserver() {
        activeSpeakerDetector.removeActiveSpeakerObserver(observer: self)
        activeSpeakerDetector.attendeesDidJoin(attendeeInfo: attendees)
        activeSpeakerDetector.volumeDidChange(volumeUpdates: volumeUpdates)
        wait(for: [activeSpeakerDidDetectExpectation], timeout: oneMilliSecondInSeconds)
        XCTAssertEqual(attendeesReceived, [])
    }

    func calculateScore(attendeeInfo: AttendeeInfo, volume: VolumeLevel) -> Double {
        calculateScoreExpectation.fulfill()
        let returnScore = scoreIndex < 5 ? scores[scoreIndex] : 0.0
        scoreIndex += 1
        return returnScore
    }

    func prioritizeVideoSendBandwidthForActiveSpeaker() -> Bool {
        prioritizeBandwidthExpectation.fulfill()
        return true
    }

    var observerId: String = "fakeObserverId"

    func activeSpeakerDidDetect(attendeeInfo: [AttendeeInfo]) {
        activeSpeakerDidDetectExpectation.fulfill()
        if attendeeInfo.isEmpty {
            emptyAttendeesReceivedExpectation.fulfill()
        }
        attendeesReceived = attendeeInfo
    }

    var scoresCallbackIntervalMs: Int = 1

    func activeSpeakerScoreDidChange(scores: [AttendeeInfo: Double]) {
        activeSpeakerScoreDidChangeExpectation.fulfill()
        scoreChangeAttendees = scores
    }
}