import { select, put } from 'redux-saga/effects';
import { fetchIssues, addLabel, removeLabel } from '../actions/issues';
import { fetchIssuesSaga } from './issues';
import { BUILD_KANBOARD_SUCCESS, buildKanboard } from '../actions/kanboards';

export function* moveCardSaga(action) {
  const { 
    boardID, fromLaneID, 
    fromPosition, toLaneID,
    toPosition,
  } = action;

  if (fromLaneID === toLaneID) return;

  const { board, kanboard} = yield select(state => {
    return {
      kanboard:  state.kanboards.byID[boardID],
      board: state.boards.byID[boardID]
    }
  });

  const toLane = kanboard.lanes[toLaneID];
  const card = toLane.cards[toPosition];

  if (!card) return;

  yield put(addLabel(card.project, card.number, board.lanes[toLaneID].issueLabel));
  yield put(removeLabel(card.project, card.number, board.lanes[fromLaneID].issueLabel));

}

export function* buildKanboardSaga(action) {
  const { board } = action;

  let kanboard;
  try {

    for (let p, i = 0; (p = board.projects[i]); i++) {
      yield* fetchIssuesSaga(fetchIssues(p));
    }

    const issues = yield select(state => state.issues);

    kanboard = createKanboard(board, issues);

  } catch(error) {
    yield put({ type: BUILD_KANBOARD_FAILURE, error });
    return
  }

  yield put({ type: BUILD_KANBOARD_SUCCESS, kanboard });
}

export function* refreshKanboardSaga(action) {
  const { project } = action;
  const boards = yield select(state => state.boards);
  const boardValues =  Object.values(boards.byID);

  for (let b, i = 0; (b = boardValues[i]); i++) {
    const hasProject = b.projects.indexOf(project) !== -1;
    if (!hasProject) continue;
    yield put(buildKanboard(b));
  }
}

function createCards(projects, issues, lane) {
  return projects.reduce((laneCards, p) => {

    const projectIssues = p in issues.byProject ? issues.byProject[p] : [];

    return projectIssues.reduce((projectCards, issue) => {
      const hasLabel = issue.labels.some(l => l.name === lane.issueLabel);

      if (hasLabel) {
        projectCards.push({
          id: issue.id,
          title: issue.title,
          project: p,
          issue: issue,
        });
      }

      return projectCards;
      
    }, laneCards);

  }, []);
}

function createLane(projects, issues, lane, index) {
  return {
    id: index,
    title: lane.title,
    cards: createCards(projects, issues, lane)
  }
}

function createKanboard(board, issues) {
  if (!board) return null;

  const kanboard = {
    id: board.id,
    lanes: board.lanes.map(createLane.bind(null, board.projects, issues)),
  };
  
  return kanboard;
}