module aimpremote;

import core.sys.windows.windows;
import std.typecons : Nullable;

private const wstring AIMPRemoteAccessClass = "AIMP2_RemoteInfo";
private const int AIMPRemoteAccessMapFileSize = 2048;

align(1)
private struct AIMPRemoteFileInfo
{
    DWORD deprecated1;
    BOOL active;
    DWORD bitRate;
    DWORD channels;
    DWORD duration;
    align(4) INT64 fileSize;
    DWORD fileMark;
    DWORD sampleRate;
    DWORD trackNumber;
    DWORD albumLength;
    DWORD artistLength;
    DWORD dateLength;
    DWORD fileNameLength;
    DWORD genreLength;
    DWORD titleLength;
    DWORD[6] deprecated2;
};

private const int WM_AIMP_COMMAND  = WM_USER + 0x75;
private const int WM_AIMP_NOTIFY   = WM_USER + 0x76;
private const int WM_AIMP_PROPERTY = WM_USER + 0x77;

private const int AIMP_RA_PROPVALUE_GET = 0;
private const int AIMP_RA_PROPVALUE_SET = 1;
private const int AIMP_RA_PROPERTY_MASK = 0xFFFFFFF0;

private const int AIMP_RA_PROPERTY_PLAYER_STATE = 0x40;
private const int AIMP_RA_PROPERTY_VOLUME = 0x50;

private const int AIMP_RA_CMD_BASE = 10;
private const int AIMP_RA_CMD_NEXT = AIMP_RA_CMD_BASE + 7;
private const int AIMP_RA_CMD_PREV = AIMP_RA_CMD_BASE + 8;

private enum TagItem {
    Album, Artist, Date, FileName, Genre, Title
}

public struct TrackInfo {
    wstring artist;
    wstring title;
    wstring genre;
};

public enum PlayerState {
    Off, Stopped, Paused, Playing
}

public static PlayerState getPlayerState() {
    auto hwnd = findPlayerWindow();
    if (hwnd == null) {
        return PlayerState.Off;
    }

    const auto state = SendMessage(hwnd, WM_AIMP_PROPERTY,
            AIMP_RA_PROPERTY_PLAYER_STATE | AIMP_RA_PROPVALUE_GET, 0);
    switch (state) {
        default: return PlayerState.Stopped;
        case 1: return PlayerState.Paused;
        case 2: return PlayerState.Playing;
    }
}

public static void setVolume(ubyte volume) {
    auto hwnd = findPlayerWindow();
    if (hwnd != null) {
        SendMessage(hwnd, WM_AIMP_PROPERTY,
                AIMP_RA_PROPERTY_VOLUME | AIMP_RA_PROPVALUE_SET, volume);
    }
}

public static void nextTrack() {
    auto hwnd = findPlayerWindow();
    if (hwnd != null) {
        SendMessage(hwnd, WM_AIMP_COMMAND, AIMP_RA_CMD_NEXT, 0);
    }
}

public static Nullable!TrackInfo getInfo() {
    import std.conv : to;
    import std.traits : EnumMembers;
    Nullable!TrackInfo result = Nullable!TrackInfo.init;

    auto haimp = OpenFileMapping(FILE_MAP_READ, 0, AIMPRemoteAccessClass.ptr);
    if (haimp == null) {
        result.nullify();
        return result;
    }
    const auto hfilemap = MapViewOfFile(haimp, FILE_MAP_READ, 0, 0, AIMPRemoteAccessMapFileSize);
    if (hfilemap == null) {
        result.nullify();
        return result;
    }

    AIMPRemoteFileInfo* info = cast(AIMPRemoteFileInfo*) hfilemap;
    auto bytes = (cast(ubyte*) hfilemap)[0 .. AIMPRemoteAccessMapFileSize];

    const wcharsize = wchar.sizeof;
    auto pbuff = AIMPRemoteFileInfo.sizeof;

    DWORD[TagItem] lengthInfo;
    wstring[TagItem] trackInfo;

    lengthInfo[TagItem.Album] = info.albumLength;
    lengthInfo[TagItem.Artist] = info.artistLength;
    lengthInfo[TagItem.Date] = info.dateLength;
    lengthInfo[TagItem.FileName] = info.fileNameLength;
    lengthInfo[TagItem.Genre] = info.genreLength;
    lengthInfo[TagItem.Title] = info.titleLength;
    foreach (index, immutable item; [EnumMembers!TagItem]) {
        auto key = to!TagItem(index);
        auto length = lengthInfo[key];
        trackInfo[key] = cast(wstring)(bytes[pbuff .. (pbuff + length * wcharsize)]);
        pbuff += length * wcharsize;
    }

    TrackInfo r = {
        artist: trackInfo[TagItem.Artist],
        title: trackInfo[TagItem.Title],
        genre: trackInfo[TagItem.Genre]
    };
    result = Nullable!TrackInfo(r);
    return result;
}

private static HWND findPlayerWindow() {
    return FindWindow(AIMPRemoteAccessClass.ptr, null);
}

/*void main() {
    import std.stdio : writeln, write;

    auto haimp = OpenFileMapping(FILE_MAP_READ, 0, AIMPRemoteAccessClass.ptr);
    auto hfilemap = MapViewOfFile(haimp, FILE_MAP_READ, 0, 0, AIMPRemoteAccessMapFileSize);

    AIMPRemoteFileInfo* info = cast(AIMPRemoteFileInfo*) hfilemap;
    write("Bitrate: ");
    writeln(info.bitRate);
    write("Samlerate: ");
    writeln(info.sampleRate);
    write("fileSize: ");
    writeln(info.fileSize);

    auto bytes = (cast(ubyte*) hfilemap)[0 .. AIMPRemoteAccessMapFileSize];
    writeln(bytes);


    const wcharsize = wchar.sizeof;
    auto pbuff = AIMPRemoteFileInfo.sizeof;

    DWORD[TagItem] lengthInfo;
    wstring[TagItem] trackInfo;

    lengthInfo[TagItem.Album] = info.albumLength;
    lengthInfo[TagItem.Artist] = info.artistLength;
    lengthInfo[TagItem.Date] = info.dateLength;
    lengthInfo[TagItem.FileName] = info.fileNameLength;
    lengthInfo[TagItem.Genre] = info.genreLength;
    lengthInfo[TagItem.Title] = info.titleLength;
    foreach (key; TagItem.min .. TagItem.max) {
        auto length = lengthInfo[key];
        trackInfo[key] = cast(wstring)(bytes[pbuff .. (pbuff + length * wcharsize)]);
        pbuff += length * wcharsize;
    }

    foreach (key, value; trackInfo) {
        writeln(value);
    }
}*/