using System.Runtime.InteropServices;

namespace DiscordRpcClient
{
    // https://github.com/discordapp/discord-rpc/blob/master/examples/button-clicker/Assets/DiscordRpc.cs
    public class DiscordRpc
    {
        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        public delegate void ReadyCallback();

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        public delegate void DisconnectedCallback(int errorCode, string message);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        public delegate void ErrorCallback(int errorCode, string message);

        public struct EventHandlers
        {
            public ReadyCallback readyCallback;
            public DisconnectedCallback disconnectedCallback;
            public ErrorCallback errorCallback;
        }

        // Values explanation and example: https://discordapp.com/developers/docs/rich-presence/how-to#updating-presence-update-presence-payload-fields
        [System.Serializable]
        public struct RichPresence
        {
            public string state; /* max 128 bytes */
            public string details; /* max 128 bytes */
            public long startTimestamp;
            public long endTimestamp;
            public string largeImageKey; /* max 32 bytes */
            public string largeImageText; /* max 128 bytes */
            public string smallImageKey; /* max 32 bytes */
            public string smallImageText; /* max 128 bytes */
            public string partyId; /* max 128 bytes */
            public int partySize;
            public int partyMax;
            public string matchSecret; /* max 128 bytes */
            public string joinSecret; /* max 128 bytes */
            public string spectateSecret; /* max 128 bytes */
            public bool instance;
        }

        [DllImport("discord-rpc-w32.dll", EntryPoint = "Discord_Initialize", CallingConvention = CallingConvention.Cdecl)]
        public static extern void Initialize(string applicationId, ref EventHandlers handlers, bool autoRegister, string optionalSteamId);

        [DllImport("discord-rpc-w32.dll", EntryPoint = "Discord_UpdatePresence", CallingConvention = CallingConvention.Cdecl)]
        public static extern void UpdatePresence(ref RichPresence presence);

        [DllImport("discord-rpc-w32.dll", EntryPoint = "Discord_RunCallbacks", CallingConvention = CallingConvention.Cdecl)]
        public static extern void RunCallbacks();

        [DllImport("discord-rpc-w32.dll", EntryPoint = "Discord_Shutdown", CallingConvention = CallingConvention.Cdecl)]
        public static extern void Shutdown();
    }
}