import { expect } from 'chai'
import fs from 'node:fs/promises'
import { execSync } from 'node:child_process'
import { useDocument } from '@terrace-lang/js'
import { createFileReader } from '@terrace-lang/js/readers/node-readline'

export async function loadTestMap(path) {
  const { next, level, head, tail, line, match } = useDocument(createFileReader(path))

  const descriptions = {}

  while (await next()) {
    if (!head() || match('#schema')) continue
    const tests = descriptions[tail()] = []

    const rootLevel = level()
    while (await next(rootLevel)) {
      if (!match('it')) continue

      const test = { it: tail(), packages: [], key: '', input: [], output: [] }
      tests.push(test)

      const testLevel = level()
      while (await next(testLevel)) {
        if (match('key')) test.key = tail()
        if (match('packages')) test.packages = tail().split(' ')

        const propertyLevel = level()
        if (match('input')) {
          // TODO: Find a way to handle newlines better.
          if (tail()) {
            test.input = tail()
            continue
          }

          while (await next(propertyLevel)) test.input.push(line(propertyLevel + 1))
          test.input = test.input.join('\n').trimEnd()
        }

        if (match('output')) {
          while (await next(propertyLevel)) test.output.push(line(propertyLevel + 1))
        }
      }

      test.input = test.input
        .replaceAll('\\n', '\n')
        .replaceAll('\\t', '\t')
        .replaceAll('\\s', ' ')

      test.output = test.output.join('\n').trimEnd()
        .replaceAll('\\n', '\n')
        .replaceAll('\\t', '\t')
        .replaceAll('\\s', ' ')

    }
  }

  return descriptions
}

export function defineTests(testMap) {
  for (const [name, tests] of Object.entries(testMap)) {
    describe(name, () => {
      for (const test of tests) {
        test.packages.forEach(pkg => {
          it(`${pkg}: ${test.it}`, async () => {
            expect(await callTest(pkg, test.key, test.input)).to.equal(test.output)
          })
        })
      }
    })
  }
}

function callTest(pkg, name, input) {
  return new Promise((resolve, reject) => {
    const stdout = execSync(`npm run --silent test ${name}`, {
      cwd: `../packages/${pkg}`,
      input
    })

    // TODO: Find a way to clean all this trimming up. Most caused by VSCode happily trimming empty spaces off the ends of lines.
    resolve(stdout.toString().trim())
  })
}