import { readFileSync, write, writeFileSync } from "fs";
import { execSync } from "child_process";
import semver from "semver";

export function isGitAvailable() {
  try {
    execSync("git --version", { stdio: "ignore" });
    return true;
  } catch (e) {
    return false;
  }
}

export function isGitRepo() {
  try {
    execSync("git rev-parse --is-inside-work-tree", { stdio: "ignore" });
    return true;
  } catch (e) {
    return false;
  }
}

export function getGitVersion() {
  let rawGitVersion;
  let gitVersion;

  try {
    rawGitVersion = execSync("git describe --tags --dirty").toString().trim();
    gitVersion = semver.coerce(rawGitVersion) || semver.coerce("0.0.0");
  } catch (e) {
    return "0.0.0";
  }

  // Git describe may return versions like v1.2.3-4-gabcdef
  // or v1.2.3-dirty or v1.2.3 or v1.2.3-4-gabcdef-dirty.
  // We need to return either a clean version or
  // append -dev for modified versions and
  // -dirty for dirty working tree.
  if (rawGitVersion.endsWith("-dirty")) {
    return gitVersion.version + "-dirty";
  } else if (rawGitVersion.includes("-")) {
    return gitVersion.version + "-dev";
  } else {
    return gitVersion.version || "0.0.0";
  }
}

export function generateVersionFile(versionFilePath) {
  if (!isGitAvailable()) {
    throw new Error("Git is required to generate version info.");
  }

  // Read package.json version
  const packageVersion = JSON.parse(
    readFileSync("package.json", { encoding: "utf-8" }),
  ).version;
  let gitVersion = packageVersion;
  let gitBaseVersion = packageVersion;
  let isRelease = true;

  if (isGitRepo()) {
    // Get version from git repository
    gitVersion = getGitVersion();
    gitBaseVersion = semver.coerce(gitVersion)?.version;

    // if git returned malformed version, throw error
    if (!gitBaseVersion || gitBaseVersion === "0.0.0") {
      throw new Error(
        "Cannot determine git version. Make sure the script is run in a git repository with tags.",
      );
    }

    // Compare git version with package.json version
    if (semver.neq(gitBaseVersion, packageVersion)) {
      throw new Error(
        `Version mismatch: package.json version is ${packageVersion}, but git version is ${gitBaseVersion}`,
      );
    }

    isRelease = gitVersion === packageVersion;
  }

  // Generate version file
  const buildDate = new Date().toISOString();
  writeFileSync(
    versionFilePath,
    `// Auto-generated version file - do not edit manually
// Generated at: ${buildDate}

export const VERSION = '${packageVersion}';
export const IS_RELEASE = ${isRelease};
export const BUILD_TIME = '${buildDate}';
`,
  );
}

if (import.meta.url === `file://${process.argv[1]}`) {
  generateVersionFile("src/version.js");
}