#!/usr/bin/env bun
import { readFileSync } from "node:fs";
import { parse } from "@kitchen-md/core";
import { Command } from "commander";
import { err, ok, type Result } from "neverthrow";
import { render } from "./render.ts";

export type ViewError = { tag: "read-failed"; path: string; cause: string };

// The union of every error a command can surface to the boundary; new fallible commands add their variants here.
export type CliError = ViewError;

export function viewFile(path: string): Result<string, ViewError> {
  return readFile(path).map((content) => render(parse(content)));
}

export function formatError(error: CliError): string {
  switch (error.tag) {
    case "read-failed":
      return `cannot read '${error.path}': ${error.cause}`;
  }
}

// The one place a throwing API is turned into a Result; nothing above this leaks exceptions.
function readFile(path: string): Result<string, ViewError> {
  try {
    return ok(readFileSync(path, "utf8"));
  } catch (error) {
    const cause = error instanceof Error ? error.message : String(error);
    return err({ tag: "read-failed", path, cause });
  }
}

const program = new Command();

program.name("kitchen").description("Read and view KitchenMD Recipe Files");

program
  .command("view")
  .description("Render a Recipe File to the terminal")
  .argument("<file>", "path to a Recipe File")
  .action((file: string) => {
    viewFile(file).match(
      (output) => process.stdout.write(output),
      (error) => {
        process.stderr.write(`kitchen: ${formatError(error)}\n`);
        process.exit(1);
      },
    );
  });

if (import.meta.main) {
  program.parse();
}