#!/usr/bin/env node --redirect-warnings=/dev/null

const { execFileSync } = require("child_process");
const { parseArgs } = require("util");
const { releaseNotesSection, releaseNotesEntries } = require("./lib/release-notes");

const GPUI_PREFIX_PATTERN = /^- \[GPUI\]\s*/i;

const USAGE = [
  "Usage: draft-release-notes <version> {stable|preview} [--gpui]",
  "",
  "By default, release notes entries prefixed with `- [GPUI]` are excluded.",
  "With --gpui, only those entries are included, with the prefix removed.",
].join("\n");

function parseArguments() {
  let values, positionals;
  try {
    ({ values, positionals } = parseArgs({
      allowPositionals: true,
      options: { gpui: { type: "boolean", default: false } },
    }));
  } catch (e) {
    return { error: e.message };
  }

  let [version, channel, ...rest] = positionals;
  if (version == null || channel == null || rest.length > 0) {
    return { error: "Expected exactly two positional arguments: <version> {stable|preview}" };
  }

  let parts = version.split(".").map((part) => Number(part));
  if (parts.length != 3 || parts.some((part) => !Number.isInteger(part))) {
    return { error: `Invalid version "${version}", expected <major>.<minor>.<patch>` };
  }

  if (channel != "stable" && channel != "preview") {
    return { error: `Invalid channel "${channel}", expected "stable" or "preview"` };
  }

  return { version, channel, parts, gpui: values.gpui };
}

function main() {
  let { error, version, channel, parts, gpui } = parseArguments();
  if (error) {
    console.error(error);
    console.error("");
    console.error(USAGE);
    process.exit(1);
  }

  // currently we can only draft notes for patch releases.
  if (parts[2] === 0) {
    process.exit(0);
  }

  let priorVersion = [parts[0], parts[1], parts[2] - 1].join(".");
  let suffix = channel == "preview" ? "-pre" : "";
  let [tag, priorTag] = [`v${version}${suffix}`, `v${priorVersion}${suffix}`];

  try {
    execFileSync("rm", ["-rf", "target/shallow_clone"]);
    execFileSync("git", [
      "clone",
      "https://github.com/zed-industries/zed",
      "target/shallow_clone",
      "--filter=tree:0",
      "--no-checkout",
      "--branch",
      tag,
      "--depth",
      100,
    ]);
    execFileSync("git", ["-C", "target/shallow_clone", "rev-parse", "--verify", tag]);
    try {
      execFileSync("git", ["-C", "target/shallow_clone", "rev-parse", "--verify", priorTag]);
    } catch (e) {
      console.error(`Prior tag ${priorTag} not found`);
      process.exit(0);
    }
  } catch (e) {
    console.error(e.stderr.toString());
    process.exit(1);
  }

  const newCommits = getCommits(priorTag, tag);

  let releaseNotes = [];
  let missing = [];
  let skipped = [];

  for (const commit of newCommits) {
    let link = "https://github.com/zed-industries/zed/pull/" + commit.pr;
    let filteredNotes = filterReleaseNotes(commit.releaseNotes, gpui);
    let notes = filteredNotes;
    if (commit.pr == "") {
      link = "https://github.com/zed-industries/zed/commits/" + commit.hash;
    } else if (!notes.includes("zed-industries/zed/issues")) {
      notes = notes + " ([#" + commit.pr + "](" + link + "))";
    }

    if (commit.releaseNotes == "") {
      missing.push("- MISSING " + commit.firstLine + " " + link);
    } else if (filteredNotes == "" || filteredNotes.startsWith("- N/A")) {
      skipped.push("- N/A " + commit.firstLine + " " + link);
    } else {
      releaseNotes.push(notes);
    }
  }

  if (releaseNotes.length === 0) {
    const compareUrl = `https://github.com/zed-industries/zed/compare/${priorTag}...${tag}#commits_bucket`;
    console.log(`No public-facing changes in this release. [View the commits](${compareUrl}).\n`);
  } else {
    console.log(releaseNotes.join("\n") + "\n");
  }
}

// Entries prefixed with `- [GPUI]` describe changes for GPUI users. They are kept
// (with the prefix removed) only when drafting GPUI release notes, and dropped otherwise.
function filterReleaseNotes(releaseNotes, gpui) {
  return releaseNotes
    .split("\n")
    .filter((line) => GPUI_PREFIX_PATTERN.test(line) == gpui)
    .map((line) => (gpui ? line.replace(GPUI_PREFIX_PATTERN, "- ") : line))
    .join("\n");
}

function getCommits(oldTag, newTag) {
  const pullRequestNumbers = execFileSync(
    "git",
    ["-C", "target/shallow_clone", "log", `${oldTag}..${newTag}`, "--format=DIVIDER\n%H|||%B"],
    { encoding: "utf8" },
  )
    .replace(/\r\n/g, "\n")
    .split("DIVIDER\n")
    .filter((commit) => commit.length > 0)
    .map((commit) => {
      let [hash, firstLine] = commit.split("\n")[0].split("|||");
      let cherryPick = firstLine.match(/\(cherry-pick #([0-9]+)\)/)?.[1] || "";
      let pr = firstLine.match(/\(#(\d+)\)$/)?.[1] || "";
      let releaseNotes = releaseNotesEntries(releaseNotesSection(commit)).join("\n");

      if (releaseNotes.includes("<public_issue_number_if_exists>")) {
        releaseNotes = "";
      }

      return {
        hash,
        pr,
        cherryPick,
        releaseNotes,
        firstLine,
      };
    });

  return pullRequestNumbers;
}

if (require.main === module) {
  main();
}