/**
 * Copyright 2017 Google Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

const Message = require('../Message.js');

module.exports.ensureReleasedAPILinks = function (
  sources,
  version,
  isReleaseVersion
) {
  // Release version is everything that doesn't include "-".
  const apiLinkRegex =
    /https:\/\/github.com\/puppeteer\/puppeteer\/blob\/[^/]*\/docs\/api.md/gi;
  const lastReleasedAPI = `https://github.com/puppeteer/puppeteer/blob/${
    isReleaseVersion ? `v${version}` : 'main'
  }/docs/api.md`;

  const messages = [];
  for (const source of sources) {
    const text = source.text();
    const newText = text.replace(apiLinkRegex, lastReleasedAPI);
    if (source.setText(newText))
      messages.push(Message.info(`GEN: updated ${source.projectPath()}`));
  }
  return messages;
};

module.exports.runCommands = function (sources, version, isReleaseVersion) {
  const messages = [];
  const commands = [];
  for (const source of sources) {
    const text = source.text();
    const commandStartRegex = /<!--\s*gen:([a-z-]+)\s*-->/gi;
    const commandEndRegex = /<!--\s*gen:stop\s*-->/gi;
    let start;

    while ((start = commandStartRegex.exec(text))) {
      // eslint-disable-line no-cond-assign
      commandEndRegex.lastIndex = commandStartRegex.lastIndex;
      const end = commandEndRegex.exec(text);
      if (!end) {
        messages.push(
          Message.error(`Failed to find 'gen:stop' for command ${start[0]}`)
        );
        return messages;
      }
      const name = start[1];
      const from = commandStartRegex.lastIndex;
      const to = end.index;
      const originalText = text.substring(from, to);
      commands.push({ name, from, to, originalText, source });
      commandStartRegex.lastIndex = commandEndRegex.lastIndex;
    }
  }

  const changedSources = new Set();
  // Iterate commands in reverse order so that edits don't conflict.
  commands.sort((a, b) => b.from - a.from);
  for (const command of commands) {
    let newText = null;
    switch (command.name) {
      case 'version':
        newText = isReleaseVersion ? `v${version}` : 'Tip-Of-Tree';
        break;
      case 'empty-if-release':
        newText = isReleaseVersion ? '' : command.originalText;
        break;
      case 'toc':
        newText = generateTableOfContents(
          command.source.text().substring(command.to)
        );
        break;
      case 'versions-per-release':
        newText = generateVersionsPerRelease();
        break;
    }
    if (newText === null) {
      messages.push(Message.error(`Unknown command 'gen:${command.name}'`));
    } else if (applyCommand(command, newText)) {
      changedSources.add(command.source);
    }
  }
  for (const source of changedSources) {
    messages.push(Message.info(`GEN: updated ${source.projectPath()}`));
  }
  return messages;
};

/**
 * @param {{name: string, from: number, to: number, source: !Source}} command
 * @param {string} editText
 * @returns {boolean}
 */
function applyCommand(command, editText) {
  const text = command.source.text();
  const newText =
    text.substring(0, command.from) + editText + text.substring(command.to);
  return command.source.setText(newText);
}

function generateTableOfContents(mdText) {
  const ids = new Set();
  const titles = [];
  let insideCodeBlock = false;
  for (const aLine of mdText.split('\n')) {
    const line = aLine.trim();
    if (line.startsWith('```')) {
      insideCodeBlock = !insideCodeBlock;
      continue;
    }
    if (!insideCodeBlock && line.startsWith('#')) titles.push(line);
  }
  const tocEntries = [];
  for (const title of titles) {
    const [, nesting, name] = title.match(/^(#+)\s+(.*)$/);
    const delinkifiedName = name.replace(/\[([^\]]+)\]\([^)]+\)/g, '$1');
    const id = delinkifiedName
      .trim()
      .toLowerCase()
      .replace(/\s/g, '-')
      .replace(/[^-0-9a-zа-яё]/gi, '');
    let dedupId = id;
    let counter = 0;
    while (ids.has(dedupId)) dedupId = id + '-' + ++counter;
    ids.add(dedupId);
    tocEntries.push({
      level: nesting.length,
      name: delinkifiedName,
      id: dedupId,
    });
  }

  const minLevel = Math.min(...tocEntries.map((entry) => entry.level));
  tocEntries.forEach((entry) => (entry.level -= minLevel));
  return (
    '\n' +
    tocEntries
      .map((entry) => {
        const prefix = entry.level % 2 === 0 ? '-' : '*';
        const padding = '  '.repeat(entry.level);
        return `${padding}${prefix} [${entry.name}](#${entry.id})`;
      })
      .join('\n') +
    '\n'
  );
}

const generateVersionsPerRelease = () => {
  const { versionsPerRelease } = require('../../../versions.js');
  const buffer = ['- Releases per Chromium version:'];
  for (const [chromiumVersion, puppeteerVersion] of versionsPerRelease) {
    if (puppeteerVersion === 'NEXT') continue;
    buffer.push(
      `  * Chromium ${chromiumVersion} - [Puppeteer ${puppeteerVersion}](https://github.com/puppeteer/puppeteer/blob/${puppeteerVersion}/docs/api.md)`
    );
  }
  buffer.push(
    `  * [All releases](https://github.com/puppeteer/puppeteer/releases)`
  );

  const output = '\n' + buffer.join('\n') + '\n';
  return output;
};