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

const { execFileSync } = require("child_process");

main();

async function main() {
  let version = process.argv[2];
  let channel = process.argv[3];
  let parts = version.split(".");

  if (
    process.argv.length != 4 ||
    parts.length != 3 ||
    parts.find((part) => isNaN(part)) != null ||
    (channel != "stable" && channel != "preview")
  ) {
    console.log("Usage: draft-release-notes <version> {stable|preview}");
    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,
    ]);
    execFileSync("git", [
      "-C",
      "target/shallow_clone",
      "rev-parse",
      "--verify",
      priorTag,
    ]);
  } 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 notes = commit.releaseNotes;
    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 (commit.releaseNotes.startsWith("- N/A")) {
      skipped.push("- N/A " + commit.firstLine + " " + link);
    } else {
      releaseNotes.push(notes);
    }
  }

  console.log(releaseNotes.join("\n") + "\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 = (commit.split(/Release notes:.*\n/i)[1] || "")
        .split("\n\n")[0]
        .trim()
        .replace(/\n(?![\n-])/g, " ");

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

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

  return pullRequestNumbers;
}
