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 reader = createFileReader(path)
  const doc = useDocument(reader)

  const descriptions = {}
  let currentSuite = null
  let currentTest = null

  for await (const node of doc) {
    if (node.head === '#schema') {
      // Skip schema declarations
      continue
    }

    if (node.head === 'describe') {
      currentSuite = node.tail
      descriptions[currentSuite] = []
      continue
    }

    if (node.head === 'it' && currentSuite) {
      currentTest = {
        it: node.tail,
        packages: [],
        key: '',
        input: '',
        output: ''
      }
      descriptions[currentSuite].push(currentTest)

      // Collect test properties
      let collectingInput = false
      let collectingOutput = false
      let inputLevel = 0

      for await (const child of node.children()) {
        if (child.head === 'key') {
          currentTest.key = child.tail
        } else if (child.head === 'packages') {
          currentTest.packages = child.tail.split(' ')
        } else if (child.head === 'input') {
          collectingInput = true
          collectingOutput = false
          inputLevel = child.level
          // If input has content on the same line
          if (child.tail) {
            currentTest.input = child.tail
          }
        } else if (child.head === 'output') {
          collectingInput = false
          collectingOutput = true
          // If output has content on the same line
          if (child.tail) {
            currentTest.output = child.tail
          }
        } else if (collectingInput) {
          // Collect input lines
          currentTest.input += (currentTest.input ? '\n' : '') + child.raw(inputLevel + 1)
        } else if (collectingOutput) {
          // Collect output lines
          currentTest.output += (currentTest.output ? '\n' : '') + child.content
        }
      }

      // Process escape sequences
      if (typeof currentTest.input === 'string') {
        currentTest.input = currentTest.input
          .replaceAll('\\n', '\n')
          .replaceAll('\\t', '\t')
          .replaceAll('\\s', ' ')
      }

      if (typeof currentTest.output === 'string') {
        currentTest.output = currentTest.output.trimEnd()
      }

      continue
    }
  }

  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())
  })
}