program DiscordCreateThread;

uses
  SysUtils, fphttpclient, fpjson, jsonparser, DateUtils;

const
  DISCORD_API = 'https://discord.com/api/v10';

function GetEnvDef(const Name, Def: string): string;
begin
  if GetEnvironmentVariable(Name) = '' then
    Result := Def
  else
    Result := GetEnvironmentVariable(Name);
end;

function GetArchiveDuration: Integer;
begin
  Result := StrToIntDef(GetEnvironmentVariable('ARCHIVE_DURATION'), 10080);
end;

function GetThreadName: string;
var
  Base: string;
begin
  Base := GetEnvironmentVariable('THREAD_NAME');
  Result := Base + ' (' + FormatDateTime('yyyy-mm-dd', Now) + ')';
end;

function HttpPost(const URL, Body, Token: string): string;
var
  Client: TFPHttpClient;
  Resp: TStringStream;
begin
  Client := TFPHttpClient.Create(nil);
  Resp := TStringStream.Create('');
  try
    Client.AddHeader('Authorization', 'Bot ' + Token);
    Client.AddHeader('Content-Type', 'application/json');
    Client.RequestBody := TStringStream.Create(Body);
    Client.Post(URL, Resp);
    Result := Resp.DataString;
  finally
    Client.Free;
    Resp.Free;
  end;
end;

var
  Token, ChannelID, ThreadMessage: string;
  ThreadBody, MessageBody, Response: string;
  JSON, MsgJSON: TJSONObject;
  Parser: TJSONData;
  ThreadID: string;

begin
  Token := GetEnvironmentVariable('DISCORD_BOT_TOKEN');
  ChannelID := GetEnvironmentVariable('DISCORD_CHANNEL_ID');
  ThreadMessage := GetEnvironmentVariable('THREAD_MESSAGE');

  JSON := TJSONObject.Create;
  JSON.Add('name', GetThreadName);
  JSON.Add('auto_archive_duration', GetArchiveDuration);
  ThreadBody := JSON.AsJSON;
  JSON.Free;

  Response := HttpPost(
    DISCORD_API + '/channels/' + ChannelID + '/threads',
    ThreadBody,
    Token
  );

  Parser := GetJSON(Response);
  ThreadID := Parser.FindPath('id').AsString;
  Parser.Free;

  if ThreadID <> '' then
  begin
    MsgJSON := TJSONObject.Create;
    MsgJSON.Add('content', ThreadMessage);
    MessageBody := MsgJSON.AsJSON;
    MsgJSON.Free;

    HttpPost(
      DISCORD_API + '/channels/' + ThreadID + '/messages',
      MessageBody,
      Token
    );
  end;
end.