#!/usr/bin/env node
import path from "node:path";
import process from "node:process";
import { pathToFileURL } from "node:url";
import {
  acquireCorrespondingSources,
  buildCorrespondingSource,
  CorrespondingSourceError,
  verifyRedistribution,
} from "./corresponding-source.js";

/**
 * `ekklesia-corresponding-source` — corresponding-source artifacts for native packages (ADR 0055).
 *
 *   ekklesia-corresponding-source acquire (--package <module package> | --recipe <name>@<version>) --cache <directory>
 *     Downloads every recorded source file the package's covered native dependencies (or the named
 *     recipe) need into the verified cache. The only subcommand that uses the network.
 *   ekklesia-corresponding-source build --package <module package> --cache <directory> --out <directory>
 *     Offline. Writes <package>-corresponding-source.tar.gz, its .sha256, <package>.redistribution.json,
 *     and <package>.source-notice.txt.
 *   ekklesia-corresponding-source verify --package <module package> [--source <archive> --metadata <json>]
 *     The public-distribution gate. Exits 0 only when the package is approved.
 */

const USAGE = [
  "Usage:",
  "  ekklesia-corresponding-source acquire (--package <archive> | --recipe <name>@<version>) --cache <directory>",
  "  ekklesia-corresponding-source build --package <archive> --cache <directory> --out <directory>",
  "  ekklesia-corresponding-source verify --package <archive> [--source <archive> --metadata <file>]",
].join("\n");

const OPTIONS: Readonly<Record<string, readonly string[]>> = Object.freeze({
  acquire: ["--package", "--recipe", "--cache"],
  build: ["--package", "--cache", "--out"],
  verify: ["--package", "--source", "--metadata"],
});
const REQUIRED: Readonly<Record<string, readonly string[]>> = Object.freeze({
  acquire: ["--cache"],
  build: ["--package", "--cache", "--out"],
  verify: ["--package"],
});

class ArgumentsError extends Error {}

export function parseCorrespondingSourceArguments(argv: readonly string[]): {
  readonly command: "acquire" | "build" | "verify";
  readonly values: ReadonlyMap<string, string>;
} {
  const [command, ...rest] = argv;
  const allowed = command === undefined ? undefined : OPTIONS[command];
  if (allowed === undefined) {
    throw new ArgumentsError(USAGE);
  }
  const values = new Map<string, string>();
  for (let index = 0; index < rest.length; index += 2) {
    const option = rest[index] ?? "";
    const value = rest[index + 1];
    if (
      !allowed.includes(option) ||
      value === undefined ||
      value.startsWith("--") ||
      values.has(option)
    ) {
      throw new ArgumentsError(USAGE);
    }
    values.set(option, option === "--recipe" ? value : path.resolve(value));
  }
  if (command === "acquire" && values.has("--package") === values.has("--recipe")) {
    throw new ArgumentsError(USAGE);
  }
  if ((REQUIRED[command as string] ?? []).some((option) => !values.has(option))) {
    throw new ArgumentsError(USAGE);
  }
  return { command: command as "acquire" | "build" | "verify", values };
}

async function main(): Promise<number> {
  try {
    const { command, values } = parseCorrespondingSourceArguments(process.argv.slice(2));
    const packageArchivePath = values.get("--package") ?? "";
    if (command === "acquire") {
      const recipe = values.get("--recipe");
      const at = recipe?.lastIndexOf("@") ?? -1;
      if (recipe !== undefined && at <= 0) {
        throw new ArgumentsError(USAGE);
      }
      const result = await acquireCorrespondingSources({
        cacheDirectory: values.get("--cache") ?? "",
        ...(recipe === undefined
          ? { packageArchivePath }
          : { recipes: [{ name: recipe.slice(0, at), version: recipe.slice(at + 1) }] }),
      });
      process.stdout.write(
        `Source cache holds all ${result.files} recorded files (${result.bytes} bytes); fetched ${result.fetched}.\n`,
      );
    } else if (command === "build") {
      const result = await buildCorrespondingSource({
        cacheDirectory: values.get("--cache") ?? "",
        outDirectory: values.get("--out") ?? "",
        packageArchivePath,
      });
      if (!result.required) {
        process.stdout.write(
          "The package redistributes no covered native code: no artifact is needed.\n",
        );
      } else {
        process.stdout.write(
          `Wrote ${path.basename(result.sourceArchivePath ?? "")}, ${result.sourceBytes} bytes\nsha256 ${result.sourceSha256}\n`,
        );
      }
    } else {
      const metadataPath = values.get("--metadata");
      const sourceArchivePath = values.get("--source");
      const approval = await verifyRedistribution({
        packageArchivePath,
        ...(metadataPath === undefined ? {} : { metadataPath }),
        ...(sourceArchivePath === undefined ? {} : { sourceArchivePath }),
      });
      process.stdout.write(
        approval.correspondingSource === undefined
          ? `Approved: ${approval.package.file} redistributes no covered native code.\n`
          : `Approved: ${approval.package.file} with ${approval.correspondingSource.file} (sha256 ${approval.correspondingSource.sha256}).\n`,
      );
    }
    return 0;
  } catch (error) {
    if (error instanceof ArgumentsError) {
      process.stderr.write(`${error.message}\n`);
      return 64;
    }
    if (error instanceof CorrespondingSourceError) {
      process.stderr.write(
        `${error.code}: ${error.message}${error.subject ? ` (${error.subject})` : ""}\n`,
      );
      return 1;
    }
    process.stderr.write("ekklesia-corresponding-source failed unexpectedly.\n");
    return 1;
  }
}

function isDirectExecution(): boolean {
  const entrypoint = process.argv[1];
  // Run through the committed launcher, which imports this file, or directly.
  return (
    entrypoint !== undefined &&
    (import.meta.url === pathToFileURL(path.resolve(entrypoint)).href ||
      path.basename(entrypoint) === "ekklesia-corresponding-source.mjs" ||
      path.basename(entrypoint) === "ekklesia-corresponding-source")
  );
}

if (isDirectExecution()) {
  process.exitCode = await main();
}