//
//  Copyright (c) 2021 Open Whisper Systems. All rights reserved.
//

import Foundation
import SignalRingRTC

@objc
protocol CallHeaderDelegate: AnyObject {
    func didTapBackButton()
    func didTapMembersButton()
}

class CallHeader: UIView {
    // MARK: - Views

    private lazy var dateFormatter: DateFormatter = {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "HH:mm:ss"
        dateFormatter.timeZone = TimeZone(identifier: "UTC")!
        dateFormatter.locale = Locale(identifier: "en_US")
        return dateFormatter
    }()

    private var callDurationTimer: Timer?
    private let callTitleLabel = MarqueeLabel()
    private let callStatusLabel = UILabel()
    private let groupMembersButton = GroupMembersButton()

    private let call: SignalCall
    private weak var delegate: CallHeaderDelegate!

    init(call: SignalCall, delegate: CallHeaderDelegate) {
        self.call = call
        self.delegate = delegate
        super.init(frame: .zero)

        call.addObserverAndSyncState(observer: self)

        let gradientLayer = CAGradientLayer()
        gradientLayer.colors = [
            UIColor.black.withAlphaComponent(0.6).cgColor,
            UIColor.black.withAlphaComponent(0).cgColor
        ]
        let gradientView = OWSLayerView(frame: .zero) { view in
            gradientLayer.frame = view.bounds
        }
        gradientView.layer.addSublayer(gradientLayer)

        addSubview(gradientView)
        gradientView.autoPinEdgesToSuperviewEdges()

        let hStack = UIStackView()
        hStack.axis = .horizontal
        hStack.spacing = 13
        hStack.layoutMargins = UIEdgeInsets(top: 0, left: 8, bottom: 0, right: 8)
        hStack.isLayoutMarginsRelativeArrangement = true
        addSubview(hStack)
        hStack.autoPinWidthToSuperview()
        hStack.autoPinEdge(toSuperviewMargin: .top)
        hStack.autoPinEdge(toSuperviewEdge: .bottom, withInset: 46)

        // Back button

        let backButton = UIButton()
        let backButtonImage = CurrentAppContext().isRTL ? #imageLiteral(resourceName: "NavBarBackRTL") : #imageLiteral(resourceName: "NavBarBack")
        backButton.setTemplateImage(backButtonImage, tintColor: .white)
        backButton.autoSetDimensions(to: CGSize(square: 40))
        backButton.imageEdgeInsets = UIEdgeInsets(top: -12, leading: -18, bottom: 0, trailing: 0)
        backButton.addTarget(delegate, action: #selector(CallHeaderDelegate.didTapBackButton), for: .touchUpInside)
        addShadow(to: backButton)

        hStack.addArrangedSubview(backButton)

        // vStack

        let vStack = UIStackView()
        vStack.axis = .vertical
        vStack.spacing = 4

        hStack.addArrangedSubview(vStack)

        // Name Label

        callTitleLabel.type = .continuous
        // This feels pretty slow when you're initially waiting for it, but when you're overlaying video calls, anything faster is distracting.
        callTitleLabel.speed = .duration(30.0)
        callTitleLabel.animationCurve = .linear
        callTitleLabel.fadeLength = 10.0
        callTitleLabel.animationDelay = 5
        // Add trailing space after the name scrolls before it wraps around and scrolls back in.
        callTitleLabel.trailingBuffer = ScaleFromIPhone5(80.0)

        callTitleLabel.font = .boldSystemFont(ofSize: Values.mediumFontSize)
        callTitleLabel.textAlignment = .center
        callTitleLabel.textColor = UIColor.white
        addShadow(to: callTitleLabel)

        vStack.addArrangedSubview(callTitleLabel)

        // Status label

        callStatusLabel.font = UIFont.ows_dynamicTypeFootnoteClamped
        callStatusLabel.textAlignment = .center
        callStatusLabel.textColor = UIColor.white
        addShadow(to: callStatusLabel)

        vStack.addArrangedSubview(callStatusLabel)

        // Group members button

        groupMembersButton.addTarget(
            delegate,
            action: #selector(CallHeaderDelegate.didTapMembersButton),
            for: .touchUpInside
        )
        addShadow(to: groupMembersButton)

        hStack.addArrangedSubview(groupMembersButton)

        updateCallTitleLabel()
        updateCallStatusLabel()
        updateGroupMembersButton()
    }

    deinit { call.removeObserver(self) }

    private func addShadow(to view: UIView) {
        view.layer.shadowOffset = .zero
        view.layer.shadowOpacity = 0.25
        view.layer.shadowRadius = 4
    }

    private func updateCallStatusLabel() {
        let callStatusText: String
        switch call.groupCall.localDeviceState.joinState {
        case .notJoined, .joining:
            callStatusText = ""
        case .joined:
            let callDuration = call.connectionDuration()
            let callDurationDate = Date(timeIntervalSinceReferenceDate: callDuration)
            var formattedDate = dateFormatter.string(from: callDurationDate)
            if formattedDate.hasPrefix("00:") {
                // Don't show the "hours" portion of the date format unless the
                // call duration is at least 1 hour.
                formattedDate = String(formattedDate[formattedDate.index(formattedDate.startIndex, offsetBy: 3)...])
            } else {
                // If showing the "hours" portion of the date format, strip any leading
                // zeroes.
                if formattedDate.hasPrefix("0") {
                    formattedDate = String(formattedDate[formattedDate.index(formattedDate.startIndex, offsetBy: 1)...])
                }
            }
            callStatusText = String(format: CallStrings.callStatusFormat, formattedDate)
        }

        callStatusLabel.text = callStatusText
        callStatusLabel.isHidden = call.groupCall.localDeviceState.joinState != .joined || call.groupCall.remoteDeviceStates.count > 1
    }

    func updateCallTitleLabel() {
        let callTitleText: String

        if call.groupCall.localDeviceState.connectionState == .reconnecting {
            callTitleText = NSLocalizedString(
                "GROUP_CALL_RECONNECTING",
                comment: "Text indicating that the user has lost their connection to the call and we are reconnecting."
            )
        } else {
            var isFirstMemberPresenting = false
            let memberNames: [String] = databaseStorage.read { transaction in
                if self.call.groupCall.localDeviceState.joinState == .joined {
                    let sortedDeviceStates = self.call.groupCall.remoteDeviceStates.sortedByAddedTime
                    isFirstMemberPresenting = sortedDeviceStates.first?.presenting == true
                    return sortedDeviceStates.map { self.contactsManager.displayName(for: $0.address, transaction: transaction) }
                } else {
                    return self.call.groupCall.peekInfo?.joinedMembers
                        .map { self.contactsManager.displayName(for: SignalServiceAddress(uuid: $0), transaction: transaction) } ?? []
                }
            }

            switch call.groupCall.localDeviceState.joinState {
            case .joined:
                switch memberNames.count {
                case 0:
                    callTitleText = NSLocalizedString(
                        "GROUP_CALL_NO_ONE_HERE",
                        comment: "Text explaining that you are the only person currently in the group call"
                    )
                case 1:
                    if isFirstMemberPresenting {
                        let formatString = NSLocalizedString(
                            "GROUP_CALL_PRESENTING_FORMAT",
                            comment: "Text explaining that a member is presenting. Embeds {member name}"
                        )
                        callTitleText = String(format: formatString, memberNames[0])
                    } else {
                        callTitleText = memberNames[0]
                    }
                default:
                    if isFirstMemberPresenting {
                        let formatString = NSLocalizedString(
                            "GROUP_CALL_PRESENTING_FORMAT",
                            comment: "Text explaining that a member is presenting. Embeds {member name}"
                        )
                        callTitleText = String(format: formatString, memberNames[0])
                    } else {
                        callTitleText = ""
                    }
                }
            default:
                switch memberNames.count {
                case 0:
                    callTitleText = ""
                case 1:
                    let formatString = NSLocalizedString(
                        "GROUP_CALL_ONE_PERSON_HERE_FORMAT",
                        comment: "Text explaining that there is one person in the group call. Embeds {member name}"
                    )
                    callTitleText = String(format: formatString, memberNames[0])
                case 2:
                    let formatString = NSLocalizedString(
                        "GROUP_CALL_TWO_PEOPLE_HERE_FORMAT",
                        comment: "Text explaining that there are two people in the group call. Embeds {{ %1$@ participant1, %2$@ participant2 }}"
                    )
                    callTitleText = String(format: formatString, memberNames[0], memberNames[1])
                case 3:
                    let formatString = NSLocalizedString(
                        "GROUP_CALL_THREE_PEOPLE_HERE_FORMAT",
                        comment: "Text explaining that there are three people in the group call. Embeds {{ %1$@ participant1, %2$@ participant2 }}"
                    )
                    callTitleText = String(format: formatString, memberNames[0], memberNames[1])
                default:
                    let formatString = NSLocalizedString(
                        "GROUP_CALL_MANY_PEOPLE_HERE_FORMAT",
                        comment: "Text explaining that there are more than three people in the group call. Embeds {{ %1$@ participant1, %2$@ participant2, %3$@ participantCount-2 }}"
                    )
                    callTitleText = String(format: formatString, memberNames[0], memberNames[1], OWSFormat.formatInt(memberNames.count - 2))
                }
            }
        }

        callTitleLabel.text = callTitleText
        callTitleLabel.isHidden = callTitleText.isEmpty
    }

    func updateGroupMembersButton() {
        let isJoined = call.groupCall.localDeviceState.joinState == .joined
        let remoteMemberCount = isJoined ? call.groupCall.remoteDeviceStates.count : Int(call.groupCall.peekInfo?.deviceCount ?? 0)
        groupMembersButton.updateMemberCount(remoteMemberCount + (isJoined ? 1 : 0))
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

extension CallHeader: CallObserver {
    func groupCallLocalDeviceStateChanged(_ call: SignalCall) {
        owsAssertDebug(call.isGroupCall)

        if call.groupCall.localDeviceState.joinState == .joined {
            if callDurationTimer == nil {
                let kDurationUpdateFrequencySeconds = 1 / 20.0
                callDurationTimer = WeakTimer.scheduledTimer(
                    timeInterval: TimeInterval(kDurationUpdateFrequencySeconds),
                    target: self,
                    userInfo: nil,
                    repeats: true
                ) {[weak self] _ in
                    self?.updateCallStatusLabel()
                }
            }
        } else {
            callDurationTimer?.invalidate()
            callDurationTimer = nil
        }

        updateCallTitleLabel()
        updateCallStatusLabel()
        updateGroupMembersButton()
    }

    func groupCallPeekChanged(_ call: SignalCall) {
        updateCallTitleLabel()
        updateGroupMembersButton()
    }

    func groupCallRemoteDeviceStatesChanged(_ call: SignalCall) {
        updateCallTitleLabel()
        updateGroupMembersButton()
    }

    func groupCallEnded(_ call: SignalCall, reason: GroupCallEndReason) {
        callDurationTimer?.invalidate()
        callDurationTimer = nil

        updateCallTitleLabel()
        updateCallStatusLabel()
        updateGroupMembersButton()
    }
}

private class GroupMembersButton: UIButton {
    private let iconImageView = UIImageView()
    private let countLabel = UILabel()

    override init(frame: CGRect) {
        super.init(frame: frame)

        autoSetDimension(.height, toSize: 40)

        iconImageView.contentMode = .scaleAspectFit
        iconImageView.setTemplateImage(#imageLiteral(resourceName: "group-solid-24"), tintColor: .ows_white)
        addSubview(iconImageView)
        iconImageView.autoPinEdge(toSuperviewEdge: .leading)
        iconImageView.autoSetDimensions(to: CGSize(square: 22))
        iconImageView.autoPinEdge(toSuperviewEdge: .top, withInset: 2)

        countLabel.font = .systemFont(ofSize: Values.mediumFontSize)
        countLabel.textColor = .ows_white
        addSubview(countLabel)
        countLabel.autoPinEdge(.leading, to: .trailing, of: iconImageView, withOffset: 5)
        countLabel.autoPinEdge(toSuperviewEdge: .trailing, withInset: 5)
        countLabel.autoAlignAxis(.horizontal, toSameAxisOf: iconImageView)
        countLabel.setContentHuggingHorizontalHigh()
        countLabel.setCompressionResistanceHorizontalHigh()
    }

    func updateMemberCount(_ count: Int) {
        countLabel.text = String(OWSFormat.formatInt(count))
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override var isHighlighted: Bool {
        didSet {
            alpha = isHighlighted ? 0.5 : 1
        }
    }
}