program KanbanModelConsole;

// Exercises TAtlasKanbanModel without a window: columns, cards, work limits,
// moves, a veto rule, change notifications and the JSON round trip.
// Every step verifies its own result; the exit code is 0 when all pass.

{$APPTYPE CONSOLE}

uses
  System.SysUtils, Atlas.Kanban;

type
  TRules = class
    Vetoes, Changes: Integer;
    ReentryRefused: Boolean;
    procedure BeforeMove(Sender: TObject; const CardID, FromColumn, ToColumn: string; var Allow: Boolean);
    procedure Changed(Sender: TObject);
  end;

// Cards may enter "done" only from "review". The callback also tries to
// mutate the board, which the model refuses while a move is in progress.
procedure TRules.BeforeMove(Sender: TObject; const CardID, FromColumn, ToColumn: string; var Allow: Boolean);
begin
  Allow := (ToColumn <> 'done') or (FromColumn = 'review');
  if not Allow then
    Inc(Vetoes);
  try
    TAtlasKanbanModel(Sender).RemoveCard(CardID);
  except
    on EAtlasKanban do
      ReentryRefused := True;
  end;
end;

procedure TRules.Changed(Sender: TObject);
begin
  Inc(Changes);
end;

procedure Check(Value: Boolean; const Message: string);
begin
  if not Value then
    raise Exception.Create('Check failed: ' + Message);
  Writeln('  ok: ', Message);
end;

// True when Action raises EAtlasKanban.
function Refused(const Action: TProc): Boolean;
begin
  Result := False;
  try
    Action;
  except
    on EAtlasKanban do
      Result := True;
  end;
end;

// The class name of the exception Action raises, or '' when it succeeds.
function ErrorClass(const Action: TProc): string;
begin
  Result := '';
  try
    Action;
  except
    on E: Exception do
      Result := E.ClassName;
  end;
end;

procedure PrintBoard(Model: TAtlasKanbanModel);
var
  C, I: Integer;
  Card: TAtlasKanbanCard;
begin
  for C := 0 to Model.ColumnCount - 1 do
  begin
    Write('  ', Model.ColumnTitle(C), ' (', Model.CardCount(C));
    if Model.ColumnLimit(C) > 0 then
      Write('/', Model.ColumnLimit(C));
    Writeln(')');
    for I := 0 to Model.CardCount(C) - 1 do
    begin
      Card := Model.Card(C, I);
      Writeln('    ', Card.ID, ': ', Card.Title);
    end;
  end;
end;

var
  Model, Copy: TAtlasKanbanModel;
  Rules: TRules;
  Before: string;
  Changes: Integer;

begin
  try
    Model := TAtlasKanbanModel.Create(nil);
    Copy := TAtlasKanbanModel.Create(nil);
    Rules := TRules.Create;
    try
      Model.BeforeMove := Rules.BeforeMove;
      Model.OnChange := Rules.Changed;

      Writeln('Building the board');
      Model.AddColumn('todo', 'To do');
      Model.AddColumn('active', 'In progress', 2);
      Model.AddColumn('review', 'Review');
      Model.AddColumn('done', 'Done');
      Model.AddCard('todo', 'order-42', 'Prepare customer order', 'Pick, pack and label');
      Model.AddCard('todo', 'invoice-7', 'Send invoice 7');
      Model.AddCard('active', 'audit', 'Stock audit');
      Model.AddCard('active', 'catalog', 'Update the catalog');
      PrintBoard(Model);
      Check((Model.ColumnCount = 4) and (Model.CardCount(0) = 2), 'four columns, two cards waiting');
      Check(Rules.Changes = 8, 'OnChange fired once per column and card');

      Writeln('Validation');
      Before := Model.ToJSON;
      Check(Refused(procedure begin Model.AddColumn('todo', 'Again'); end), 'duplicate column id refused');
      Check(Refused(procedure begin Model.AddCard('todo', 'audit', 'Duplicate'); end), 'duplicate card id refused');
      Check(Refused(procedure begin Model.AddCard('active', 'extra', 'Over the limit'); end), 'work limit refuses a third card');
      Check(Refused(procedure begin Model.MoveCard('order-42', 'active'); end), 'work limit refuses a move into a full column');
      Check(Refused(procedure begin Model.MoveCard('order-42', 'review', 5); end), 'destination index out of range');
      Check(Refused(procedure begin Model.RemoveCard('nobody'); end), 'unknown card refused');
      Check(Model.ToJSON = Before, 'refused operations leave the board unchanged');

      Writeln('Moving cards');
      Changes := Rules.Changes;
      Check(Model.MoveCard('audit', 'review'), 'audit goes to review');
      Check(Rules.ReentryRefused, 'BeforeMove cannot mutate the board');
      Check(Model.MoveCard('order-42', 'active'), 'the freed slot accepts order-42');
      Check(not Model.MoveCard('catalog', 'done'), 'veto: catalog cannot skip review');
      Check((Rules.Vetoes = 1) and (Model.Card(1, 0).ID = 'catalog'), 'vetoed card stays where it was');
      Check(Model.MoveCard('audit', 'done'), 'audit may finish from review');
      Check(Model.MoveCard('order-42', 'active', 0), 'explicit index reorders inside a column');
      Check((Model.Card(1, 0).ID = 'order-42') and (Model.Card(1, 1).ID = 'catalog'), 'order-42 is first in progress');
      Check(Model.MoveCard('order-42', 'active', 0), 'a move to the same place succeeds');
      Check(Rules.Changes = Changes + 4, 'only real moves fire OnChange');
      PrintBoard(Model);

      Writeln('JSON round trip');
      Before := Model.ToJSON;
      Writeln('  ', Before);
      Copy.LoadJSON(Before);
      Check(Copy.ToJSON = Before, 'a second model loads the same board');
      Check(Refused(procedure begin Model.LoadJSON('{"schema":2,"columns":[]}'); end), 'unknown schema refused');
      Check(Refused(procedure begin Model.LoadJSON('not json'); end), 'invalid text refused');
      Check(ErrorClass(procedure begin Model.LoadJSON('{"schema":1,"columns":[{"id":"x","title":"X","limit":0,' +
        '"cards":[{"id":"c","title":"C"}]}]}'); end) = 'EJSONException', 'a card without "detail" fails in the JSON reader');
      Check(Model.ToJSON = Before, 'failed imports leave the board intact');

      Writeln('Editing and clearing');
      // There is no rename: replace the card and put it back where it was.
      Model.RemoveCard('catalog');
      Model.AddCard('active', 'catalog', 'Update the autumn catalog', 'New prices');
      Check(Model.MoveCard('catalog', 'active', 0), 'the replacement goes back to the top');
      Check((Model.Card(1, 0).ID = 'catalog') and (Model.Card(1, 0).Detail = 'New prices'), 'same id, new title and detail');
      Model.RemoveCard('invoice-7');
      Check(Model.CardCount(0) = 0, 'removed card is gone');
      Model.LoadJSON('{"schema":1,"columns":[]}');
      Check(Model.ColumnCount = 0, 'loading an empty document clears the board');
      Writeln('All checks passed.');
    finally
      Rules.Free;
      Copy.Free;
      Model.Free;
    end;
  except
    on E: Exception do
    begin
      Writeln(E.ClassName, ': ', E.Message);
      Halt(1);
    end;
  end;
end.