import yargs from 'yargs';
import { hideBin } from 'yargs/helpers';
import { project } from '@theoryofnekomata/orbis-core';
import { writeFile } from 'fs/promises';
import { basename, dirname, resolve } from 'path';

type ProjectArgs = { input: string, projection: string, output?: string };

const main = async (argv: string | readonly string[]) => {
  await yargs
    .option('interactive', {
      alias: 'i',
    })
    .command({
      command: 'project <input> <projection>',
      aliases: 'p',
      describe: 'Project an equirectangular PNG image to another projection.',
      builder: (y) => y
        .option('output', {
          alias: 'o',
        })
        .option('width', {
          alias: 'w',
        })
        .coerce('output', (output) => {
          if (!output) {
            return null;
          }
          if (typeof output !== 'string') {
            return null;
          }
          return output;
        })
        .option('bounds', {
          alias: 'b',
          default: '-180,90;180,-90',
        }),
      handler: async (projectArgvRaw) => {
        const projectArgv = projectArgvRaw as unknown as ProjectArgs;
        const outputPng = await project(projectArgv.input, [projectArgv.projection]);
        const outputFilename = projectArgv.output ?? `${basename(projectArgv.input, '.png')}.out.png`;
        const outputPath = resolve(
          dirname(projectArgv.input),
          outputFilename.endsWith('.png') ? outputFilename : `${outputFilename}.png`
        );
        await writeFile(outputPath, outputPng);
        process.stdout.write(`Created output file: ${outputPath}\n`);
      },
    })
    .demandCommand(1, 'Please specify a command')
    .help()
    .parse(
      hideBin((Array.isArray(argv) ? argv : [argv]) as string[]),
    );
};

void main(process.argv);