/**
 * Author: dkanus
 * Home repo: https://www.insultplayers.ru/git/AcediaFramework/AcediaCore
 * License: GPL
 * Copyright 2023 Anton Tarasenko
 *------------------------------------------------------------------------------
 * This file is part of Acedia.
 *
 * Acedia is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 3 of the License, or
 * (at your option) any later version.
 *
 * Acedia is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
 */
class PlayerNotificationQueue extends AcediaObject
    config(AcediaSystem);

//! Manages queue of notifications that should be displayed for a certain player.
//!
//! Pushes messages one-by-one, once its their time to be displayed and making sure that only up to
//! one message per channel is ever in queue.
//!
//! A channel is a way to group related notifications together.
//! Its purpose is to control the display of notifications in a more organized and efficient manner.
//! Each channel can only have one message in the queue at a time.
//! This ensures that only the most relevant or up-to-date message is displayed to the player.

/// Describes a single notification: title (optional, can be `none`) + message body, channel
/// and timeout.
struct Notification {
    var Text title;
    var Text body;
    var float duration;
    var Text channel;
};
var private array<Notification> notificationQueue;

/// We need this variable to keep track of which channel the currently displayed message belongs to,
/// so that we can ensure that only one message is displayed at a time for each channel.
/// This variable allows us to easily check if a new message belongs to the same channel as
/// the currently displayed message, and if so, replace the currently displayed message with
/// the new one.
var private Text currentChannel;
/// Reference to the `PlayerController` for the player that owns this queue
var private NativeActorRef playerControllerRef;
/// Timer until next notification can be displayed
///
/// `none` if queue currently doesn't display any notifications
var private Timer nextNotificationTimer;

/// Maximum time that a notification is allowed to be displayed on the player's screen
var private const config float maximumNotifyTime;

var private const int CODEPOINT_NEWLINE;

protected function Finalizer() {
    local int i;

    for (i = 0; i < notificationQueue.length; i += 1) {
        _.memory.Free(notificationQueue[i].title);
        _.memory.Free(notificationQueue[i].body);
    }
    notificationQueue.length = 0;
    _.memory.Free(nextNotificationTimer);
    _.memory.Free(playerControllerRef);
    nextNotificationTimer = none;
    playerControllerRef = none;
}

/// Set owner `PlayerController` for this queue
public final /*native*/ function SetupController(NativeActorRef newPlayerControllerRef) {
    local PlayerController oldController, newController;

    if (playerControllerRef != none) {
        oldController = PlayerController(playerControllerRef.Get());
    }
    if (newPlayerControllerRef != none) {
        newController = PlayerController(newPlayerControllerRef.Get());
    }
    if (oldController != newController) {
        InterruptScheduling();
        _.memory.Free(playerControllerRef);
        if (newPlayerControllerRef != none) {
            newPlayerControllerRef.NewRef();
            playerControllerRef = newPlayerControllerRef;
            SetupNextNotification(none);
        } else {
            playerControllerRef = none;
        }
    }
}

/// Sends a text message to notify the player about a particular event or situation, displayed
/// as a notification.
///
/// While the header parameter is optional, it is recommended to provide a meaningful header
/// to give the player context about the notification. The duration parameter suggests the time
/// that the message should be displayed for, but the actual duration may be limited by the
/// implementation or server settings.
///
/// The [`channel`] parameter (case-sensitive) allows you to group related notifications together by
/// assigning them to a specific channel.
/// Each channel can only have one message in the queue at any given time.
/// For instance, when conducting a vote, the old message about the vote's start can be quickly
/// replaced with a newer message about the vote's end.
/// Notifications without a channel `none` can have any number of messages queued up.
///
/// Acedia uses "voting" channel for voting.
public final function AddNotification(
    BaseText title,
    BaseText body,
    float duration,
    BaseText channel
) {
    local int i, newNotificationIndex;
    local Notification newNotification;

    if (body == none) {
        return;
    }
    if (title != none) {
        newNotification.title = title.Copy();
    }
    if (channel != none) {
        newNotification.channel = channel.Copy();
    }
    newNotification.body = body.Copy();
    newNotification.duration = duration;
    newNotificationIndex = notificationQueue.length;
    // Make sure there is only one message per channel by replacing the old one
    if (currentChannel != none && currentChannel.Compare(channel)) {
        SetupNotification(/*take*/ newNotification);
        return;
    }
    if (channel != none) {
        for (i = 0; i < notificationQueue.length; i += 1) {
            if (channel.Compare(notificationQueue[i].channel)) {
                _.memory.Free3(
                    notificationQueue[i].title,
                    notificationQueue[i].body,
                    notificationQueue[i].channel);
                newNotificationIndex = i;
                break;
            }
        }
    }
    notificationQueue[newNotificationIndex] = newNotification;
    if (!IsUpdateScheduled()) {
        SetupNextNotification(none);
    }
}

// Sets up [`SetupNextNotification()`] to be called after [`timeUntilNextUpdate`]
private function ScheduleUpdate(float timeUntilNextUpdate) {
    if (nextNotificationTimer == none) {
        nextNotificationTimer = __level().time.StartRealTimer(timeUntilNextUpdate, false);
        nextNotificationTimer.OnElapsed(nextNotificationTimer).connect = SetupNextNotification;
    } else {
        nextNotificationTimer.SetInterval(timeUntilNextUpdate);
        nextNotificationTimer.Start();
    }
}

private function bool IsUpdateScheduled() {
    return (nextNotificationTimer != none);
}

// Prevents scheduled [`SetupNextNotification()`] call from going off
private function InterruptScheduling() {
    _.memory.Free(nextNotificationTimer);
    nextNotificationTimer = none;
}

// Properly translates [`contents`] into a colored [`string`] before setting it up as
// a [`PlayerController`]'s progress message at the given line index.
private function SetupProgressLine(
    int lineIndex,
    BaseText contents,
    PlayerController playerController
) {
    local string contentsAsString;
    local BaseText.Formatting startingFormatting;

    if (contents == none)           return;
    if (playerController == none)   return;

    // Drop first colored tag, since we'll set first color through `playerController.progressColor`
    contentsAsString = Mid(contents.ToColoredString(,, _.color.white), 4);
    startingFormatting = contents.GetFormatting(0);
    if (startingFormatting.isColored) {
        playerController.SetProgressMessage(lineIndex, contentsAsString, startingFormatting.color);
    }
    else {
        playerController.SetProgressMessage(lineIndex, contentsAsString, _.color.white);
    }
}

// Prints [`notification`] on given lines, respecting line breaks inside it as much as possible
// (creates up to [`maxLines`], replacing the rest of line breaks with whitespaces)
private function PrintNotifcationAt(
    PlayerController playerController,
    BaseText notification,
    int startingLine,
    int maxLines
) {
    local int i, j;
    local MutableText lastLine;
    local array<BaseText> lines;

    if (notification == none)   return;
    if (startingLine < 0)       return;
    if (startingLine > 3)       return;

    lines = notification.SplitByCharacter(_.text.CharacterFromCodePoint(CODEPOINT_NEWLINE),, true);
    for (i = 0; i < lines.length; i += 1) {
        if (i + 1 < maxLines) {
            SetupProgressLine(i + startingLine, lines[i], playerController);
        } else {
            lastLine = lines[i].MutableCopy();
            for (j = i + 1; j < lines.length; j += 1) {
                lastLine.Append(P(" "));
                lastLine.Append(lines[j]);
            }
            SetupProgressLine(startingLine + maxLines - 1, lastLine, playerController);
            _.memory.Free(lastLine);
            break;
        }
    }
}

private function SetupNextNotification(Timer callerInstance) {
    local Notification nextNotification;

    if (notificationQueue.length <= 0) {
        InterruptScheduling();
        return;
    }
    nextNotification = notificationQueue[0];
    notificationQueue.Remove(0, 1);
    SetupNotification(/*take*/ nextNotification);
}

private function SetupNotification(/*take*/ Notification notification) {
    local int titleShift;
    local MutableText upperCaseTitle;
    local PlayerController playerController;

    // Get appropriate [`PlayerController`] and next notification
    playerController = PlayerController(playerControllerRef.Get());
    if (playerController == none) {
        _.memory.Free(playerControllerRef);
        playerControllerRef = none;
        InterruptScheduling();
        return;
    }
    _.memory.Free(currentChannel);
    currentChannel = notification.channel;
    notification.duration = FMin(notification.duration, maximumNotifyTime);
    if (notification.duration <= 0) {
        notification.duration = 10.0;
    }

    // And print
    playerController.ClearProgressMessages();
    playerController.SetProgressTime(notification.duration);
    if (notification.title != none) {
        upperCaseTitle = notification.title.UpperMutableCopy();
        upperCaseTitle.ChangeDefaultColor(_.color.TextHeader);
        PrintNotifcationAt(playerController, upperCaseTitle, 0, 1);
        titleShift = 1;
        _.memory.Free(upperCaseTitle);
    }
    PrintNotifcationAt(playerController, notification.body, titleShift, 4 - titleShift);
    ScheduleUpdate(notification.duration);
    // We moved channel's reference into `currentChannel`
    _.memory.Free2(notification.title, notification.body);
}

defaultproperties {
    CODEPOINT_NEWLINE = 10
    maximumNotifyTime = 20.0
}