program DiscordCreateThread;
{$MODE OBJFPC}
{$H+}
uses
  SysUtils, Classes, fphttpclient, opensslsockets, DateUtils;

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

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

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

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

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

procedure RunCore;
var
  Token, ChannelID, ThreadMessage: string;
  ThreadBody, MessageBody, Response: string;
  ThreadIDStart, ThreadIDEnd: Integer;
  ThreadID: string;
begin
  Token := GetEnvironmentVariable('DISCORD_BOT_TOKEN');
  ChannelID := GetEnvironmentVariable('DISCORD_CHANNEL_ID');
  ThreadMessage := GetEnvironmentVariable('THREAD_MESSAGE');

  ThreadBody := Format(
    '{"name":"%s","auto_archive_duration":%d}',
    [StringReplace(GetThreadName, '"', '\"', [rfReplaceAll]), GetArchiveDuration]
  );

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

  ThreadIDStart := Pos('"id":"', Response);
  if ThreadIDStart > 0 then
  begin
    Inc(ThreadIDStart, 6);
    ThreadIDEnd := Pos('"', Response, ThreadIDStart);
    ThreadID := Copy(Response, ThreadIDStart, ThreadIDEnd - ThreadIDStart);

    if ThreadID <> '' then
    begin
      MessageBody := Format('{"content":"%s"}', [StringReplace(ThreadMessage, '"', '\"', [rfReplaceAll])]);
      HttpPost(DISCORD_API + '/channels/' + ThreadID + '/messages', MessageBody, Token);
    end;
  end;
end;

// RUN_AT format: "<day_of_week>:<hour>:<minute>"
// day_of_week: 1=Sunday, 2=Monday, 3=Tuesday, 4=Wednesday, 5=Thursday, 6=Friday, 7=Saturday
function ParseRunAt(out TargetDow, TargetHour, TargetMinute: Integer): Boolean;
var
  RunAt: string;
  Parts: TStringList;
begin
  ParseRunAt := False;
  RunAt := GetEnvironmentVariable('RUN_AT');
  if RunAt = '' then Exit;

  Parts := TStringList.Create;
  try
    Parts.Delimiter := ':';
    Parts.StrictDelimiter := True;
    Parts.DelimitedText := RunAt;

    if Parts.Count < 3 then Exit;

    TargetDow    := StrToIntDef(Parts[0], -1);
    TargetHour   := StrToIntDef(Parts[1], -1);
    TargetMinute := StrToIntDef(Parts[2], -1);

    if (TargetDow < 1) or (TargetDow > 7) then Exit;
    if (TargetHour < 0) or (TargetHour > 23) then Exit;
    if (TargetMinute < 0) or (TargetMinute > 59) then Exit;

    ParseRunAt := True;
  finally
    Parts.Free;
  end;
end;

function ShouldFire(TargetDow, TargetHour, TargetMinute: Integer): Boolean;
var
  H, M, S, MS: Word;
begin
  DecodeTime(SysUtils.Now, H, M, S, MS);
  ShouldFire := (DayOfWeek(SysUtils.Now) = TargetDow) and
                (Integer(H) = TargetHour) and
                (Integer(M) = TargetMinute);
end;

const
  DAY_NAMES: array[1..7] of string = (
    'Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'
  );

var
  Fired: Boolean;
  LastCheckedMinute: Integer;
  CurrentMinute: Integer;
  H, M, S, MS: Word;
  TargetDow, TargetHour, TargetMinute: Integer;

begin
  if not ParseRunAt(TargetDow, TargetHour, TargetMinute) then
  begin
    WriteLn('Error: RUN_AT environment variable is not set or invalid.');
    WriteLn('Format: RUN_AT=<day_of_week>:<hour>:<minute>');
    WriteLn('Example (Tuesday 9:00): RUN_AT=3:9:0');
    Halt(1);
  end;

  WriteLn('===========================================');
  WriteLn('  Discord Thread Scheduler');
  WriteLn('===========================================');
  WriteLn(Format('  Started at : %s', [FormatDateTime('yyyy-mm-dd hh:nn:ss', SysUtils.Now)]));
  WriteLn(Format('  Channel ID : %s', [GetEnvironmentVariable('DISCORD_CHANNEL_ID')]));
  WriteLn(Format('  Thread name: %s', [GetEnvironmentVariable('THREAD_NAME')]));
  WriteLn(Format('  Fires every: %s at %02d:%02d', [DAY_NAMES[TargetDow], TargetHour, TargetMinute]));
  WriteLn('===========================================');

  Fired := False;
  LastCheckedMinute := -1;

  while True do
  begin
    DecodeTime(SysUtils.Now, H, M, S, MS);
    CurrentMinute := Integer(H) * 60 + Integer(M);

    if CurrentMinute <> LastCheckedMinute then
    begin
      LastCheckedMinute := CurrentMinute;

      if ShouldFire(TargetDow, TargetHour, TargetMinute) then
      begin
        if not Fired then
        begin
          WriteLn(Format('[%s] Trigger matched, running core...',
            [FormatDateTime('yyyy-mm-dd hh:nn', SysUtils.Now)]));
          try
            RunCore;
            WriteLn('Core executed successfully.');
          except
            on E: Exception do
              WriteLn('Error: ', E.Message);
          end;
          Fired := True;
        end;
      end
      else
        Fired := False;
    end;

    Sleep(10000);
  end;
end.