// ==UserScript==
// @name         GitHub Projects Story Points
// @namespace    pkosiec
// @version      0.2.1
// @description  Use Story Points in GitHub Project board without a hassle. No labels or issue title modifications needed.
// @author       Pawel Kosiec
// @website      https://github.com/pkosiec/gh-projects-story-points/
// @match        https://github.com/*/projects/*
// @grant        none
// @license      MIT
// @run-at       document-idle
// ==/UserScript==

(function () {
  "use strict";

  /**
   * Configuration
   */

  const refreshInterval = 2000;
  const highlightNotEstimatedCards = true;
  const showTotalBoardStoryPoints = true;

  // the column cards will be excluded from validation and counting Story Points:
  // both from column and board Story Points count.
  const excludedColumns = ["Inbox"];

  // the column cards will be validated as usual and the column summary will be visible,
  // but the Story Points from this column won't be counted towards the board total Story Points.
  const excludedColumnsFromBoardStoryPointsCount = ["Backlog"];

  /**
   * Internal values
   */

  const storyPointsColumnSummaryClass = "ghp-sp-column-summary";
  const storyPointsBoardSummaryClass = "ghp-sp-board-summary";
  const notEstimatedCardClass = "ghp-sp-not-estimated";
  const invalidEstimationCardClass = "ghp-sp-estimation-invalid";

  const estimationBlockSelector = `pre[lang="est"]`;
  const columnSelector = ".project-column";
  const columnHeaderSelector = ".details-container";
  const columnHeaderNameSelector = `${columnHeaderSelector} .js-project-column-name`;
  const cardSelector = "article.issue-card";
  const projectBoardSelector = ".project-columns-container";
  const boardHeaderSelector = ".project-header .project-header-controls";
  const customCSS = `
  ${cardSelector}.${notEstimatedCardClass} {
    background: #fff7bb!important;
  }

  ${cardSelector}.${invalidEstimationCardClass} {
    background: #fbc8c8!important;
  }

  .${storyPointsColumnSummaryClass} {
    padding: 0 8px 8px;
  }

  .${storyPointsColumnSummaryClass} p, .${storyPointsBoardSummaryClass} p {
    margin: 0;
  }
 `;

  if (document.querySelector(projectBoardSelector) === null) {
    return;
  }

  console.log("Running GitHub Projects Story Points...");
  includeCustomCSS();
  runPeriodically(refreshInterval);

  function runPeriodically(refreshInterval) {
    setInterval(() => {
      run();
    }, refreshInterval);
  }

  function run() {
    removeExistingSummaries();

    const columns = getColumns();

    let totalBoardStoryPoints = 0;
    columns.forEach((column) => {
      if (excludedColumns.includes(column.name)) {
        addExcludedLabelForColumnIfShould(column.node);
        return;
      }

      const cardNodes = getCardNodes(column.node);

      const totalCardNodesCount = cardNodes.length;
      let estimatedCardsCount = 0;
      let totalColumnStoryPoints = 0;
      cardNodes.forEach((cardNode) => {
        try {
          const cardStoryPoints = getCardStoryPoints(cardNode);
          totalColumnStoryPoints += cardStoryPoints;
          estimatedCardsCount++;
        } catch (err) {
          highlightCard(cardNode, err);
        }
      });

      if (!excludedColumnsFromBoardStoryPointsCount.includes(column.name)) {
        totalBoardStoryPoints += totalColumnStoryPoints;
      }

      addStoryPointsColumnSummary(column.node, {
        totalColumnStoryPoints,
        estimatedCardsCount,
        totalCardNodesCount,
      });
    });

    if (showTotalBoardStoryPoints) {
      const boardHeaderNode = getBoardHeaderNode();
      addStoryPointsBoardSummary(boardHeaderNode, totalBoardStoryPoints);
    }
  }

  function removeExistingSummaries() {
    document
      .querySelectorAll(`.${storyPointsColumnSummaryClass}`)
      .forEach((elem) => elem.remove());

    const boardSummaryNode = document.querySelector(
      `${boardHeaderSelector} .${storyPointsBoardSummaryClass}`
    );
    if (boardSummaryNode !== null) {
      boardSummaryNode.remove();
    }
  }

  function getBoardHeaderNode() {
    return document.querySelector(boardHeaderSelector);
  }

  function getColumns() {
    const columnNodes = document.querySelectorAll(columnSelector);
    const columnNodesArray = [...columnNodes];

    return columnNodesArray.map((columnNode) => {
      const headerNode = columnNode.querySelector(columnHeaderNameSelector);
      if (headerNode === null) {
        return {
          node: columnNode,
        };
      }

      return {
        node: columnNode,
        name: headerNode.innerText,
      };
    });
  }

  function getCardNodes(columnNode) {
    return columnNode.querySelectorAll(cardSelector);
  }

  function highlightCard(node, err) {
    switch (true) {
      case err instanceof NoEstimationCardError:
        if (highlightNotEstimatedCards) {
          node.classList.add(notEstimatedCardClass);
        }
        return;
      case err instanceof InvalidEstimationCardError:
        node.classList.add(invalidEstimationCardClass);
        return;
    }
  }

  class NoEstimationCardError extends Error {}
  class InvalidEstimationCardError extends Error {}

  function getCardStoryPoints(node) {
    const estimationCodeBlockNodes = node.querySelectorAll(
      estimationBlockSelector
    );

    if (estimationCodeBlockNodes.length === 0) {
      throw new NoEstimationCardError();
    }

    if (estimationCodeBlockNodes.length > 1) {
      throw new InvalidEstimationCardError();
    }

    const storyPoints = getStoryPoints(estimationCodeBlockNodes[0]);
    if (storyPoints < 0) {
      throw new InvalidEstimationCardError();
    }

    return storyPoints;
  }

  function getStoryPoints(estimationCodeBlockNode) {
    const estimationText = estimationCodeBlockNode.innerText.replace("SP:", "");
    const estNumber = Number(estimationText);

    if (isNaN(estNumber) || estNumber < 0) {
      return -1;
    }

    return estNumber;
  }

  function includeCustomCSS() {
    const styleNode = document.createElement("style");
    styleNode.type = "text/css";
    styleNode.appendChild(document.createTextNode(customCSS));

    document.head.appendChild(styleNode);
  }

  function addStoryPointsColumnSummary(
    columnNode,
    { totalColumnStoryPoints, estimatedCardsCount, totalCardNodesCount }
  ) {
    const projectColumnHeader = columnNode.querySelector(columnHeaderSelector);

    const summaryDiv = document.createElement("div");
    summaryDiv.className = storyPointsColumnSummaryClass;
    summaryDiv.innerHTML = `<p>
          <strong>Story Points:</strong> ${totalColumnStoryPoints} (Estimated: ${estimatedCardsCount}/${totalCardNodesCount})
        </p>`;
    projectColumnHeader.appendChild(summaryDiv);
  }

  function addExcludedLabelForColumnIfShould(columnNode) {
    const projectColumnHeader = columnNode.querySelector(columnHeaderSelector);

    if (
      projectColumnHeader.querySelector(`.${storyPointsColumnSummaryClass}`) !==
      null
    ) {
      return;
    }

    const excludedColumnDiv = document.createElement("div");
    excludedColumnDiv.className = storyPointsColumnSummaryClass;
    excludedColumnDiv.innerHTML = `<p>
          Story Points count disabled
        </p>`;
    projectColumnHeader.appendChild(excludedColumnDiv);
  }

  function addStoryPointsBoardSummary(boardHeaderNode, totalBoardStoryPoints) {
    const summaryDiv = document.createElement("div");
    summaryDiv.className = storyPointsBoardSummaryClass;

    let additionalContent = "";
    if (
      excludedColumns.length > 0 ||
      excludedColumnsFromBoardStoryPointsCount.length > 0
    ) {
      const ignoredColumns = [
        ...new Set([
          ...excludedColumns,
          ...excludedColumnsFromBoardStoryPointsCount,
        ]),
      ];
      additionalContent = `<br/><small>Ignored columns: ${ignoredColumns.join(
        ", "
      )}</small>`;
    }

    summaryDiv.innerHTML = `<p>
          <strong>Board Story Points:</strong> ${totalBoardStoryPoints}${additionalContent}
        </p>`;

    boardHeaderNode.prepend(summaryDiv);
  }
})();