import { jest } from '@jest/globals'
import fs from 'fs/promises'
import revalidator from 'revalidator'
import semver from 'semver'
import { allVersions } from '../../lib/all-versions.js'
import { supported, next, nextNext, deprecated } from '../../lib/enterprise-server-releases.js'
import { getLiquidConditionals } from '../../script/helpers/get-liquid-conditionals.js'
import allowedVersionOperators from '../../lib/liquid-tags/ifversion-supported-operators.js'
import featureVersionsSchema from '../helpers/schemas/feature-versions-schema.js'
import walkFiles from '../../script/helpers/walk-files'
import frontmatter from '../../lib/frontmatter.js'
import loadSiteData from '../../lib/site-data.js'

const versionShortNames = Object.values(allVersions).map((v) => v.shortName)
const versionShortNameExceptions = ['ghae-next', 'ghae-issue-']

jest.useFakeTimers('legacy')

const siteData = loadSiteData()
const featureVersions = Object.entries(siteData.en.site.data.features)
const featureVersionNames = featureVersions.map((fv) => fv[0])

const versionKeywords = versionShortNames
  .concat(['currentVersion', 'enterpriseServerReleases'])
  .concat(featureVersionNames)

// Make sure data/features/*.yml contains valid versioning.
describe('lint feature versions', () => {
  test.each(featureVersions)('data/features/%s matches the schema', (_, featureVersion) => {
    const { errors } = revalidator.validate(featureVersion, featureVersionsSchema)

    const errorMessage = errors
      .map((error) => {
        // Make this one message a little more readable than the error we get from revalidator
        // when additionalProperties is set to false and an additional prop is found.
        const errorToReport =
          error.message === 'must not exist' && error.actual.feature
            ? `feature: '${error.actual.feature}'`
            : JSON.stringify(error.actual, null, 2)

        return `- [${error.property}]: ${errorToReport}, ${error.message}`
      })
      .join('\n')

    expect(errors.length, errorMessage).toBe(0)
  })
})

const allFiles = walkFiles('content', '.md').concat(walkFiles('data', ['.yml', '.md']))

// Quoted strings in Liquid, like {% if "foo" %}, will always evaluate true _because_ they are strings.
// Instead we need to use unquoted variables, like {% if foo %}.
const stringInLiquidRegex = /{% (?:if|ifversion|elseif|unless) (?:"|').+?%}/g

// Make sure the `if` and `ifversion` Liquid tags in content and data files are valid.
describe('lint Liquid versioning', () => {
  describe.each(allFiles)('%s', (file) => {
    let fileContents, ifversionConditionals, ifConditionals

    beforeAll(async () => {
      fileContents = await fs.readFile(file, 'utf8')
      const { data, content: bodyContent } = frontmatter(fileContents)

      ifversionConditionals = getLiquidConditionals(data, ['ifversion', 'elsif']).concat(
        getLiquidConditionals(bodyContent, ['ifversion', 'elsif'])
      )

      ifConditionals = getLiquidConditionals(data, 'if').concat(
        getLiquidConditionals(bodyContent, 'if')
      )
    })

    // `ifversion` supports both standard and feature-based versioning.
    test('ifversion conditionals are valid', async () => {
      const errors = validateIfversionConditionals(ifversionConditionals)
      expect(errors.length, errors.join('\n')).toBe(0)
    })

    // Now that `ifversion` supports feature-based versioning, we should have few other `if` tags.
    test('ifversion, not if, is used for versioning', async () => {
      const ifsForVersioning = ifConditionals.filter((cond) =>
        versionKeywords.some((keyword) => cond.includes(keyword))
      )
      const errorMessage = `Found ${
        ifsForVersioning.length
      } "if" conditionals used for versioning! Use "ifversion" instead.
    ${ifsForVersioning.join('\n')}`
      expect(ifsForVersioning.length, errorMessage).toBe(0)
    })

    test('does not contain Liquid that evaluates strings (because they are always true)', async () => {
      const matches = fileContents.match(stringInLiquidRegex) || []
      const message =
        'Found Liquid conditionals that evaluate a string instead of a variable. Remove the quotes around the variable!'
      const errorMessage = `${message}\n  - ${matches.join('\n  - ')}`
      expect(matches.length, errorMessage).toBe(0)
    })
  })
})

function validateVersion(version) {
  return (
    versionShortNames.includes(version) ||
    versionShortNameExceptions.some((exception) => version.startsWith(exception)) ||
    featureVersionNames.includes(version)
  )
}

function validateIfversionConditionals(conds) {
  const errors = []

  conds.forEach((cond) => {
    // Where `cond` is an array of strings, where each string may have one of the following space-separated formats:
    // * Length 1: `<version>` (example: `fpt`)
    // * Length 2: `not <version>` (example: `not ghae`)
    // * Length 3: `<version> <operator> <release>` (example: `ghes > 3.0`)
    //
    // Note that Lengths 1 and 2 may be used with feature-based versioning, but NOT Length 3.
    const condParts = cond.split(/ (or|and) /).filter((part) => !(part === 'or' || part === 'and'))

    condParts.forEach((str) => {
      const strParts = str.split(' ')
      // if length = 1, this should be a valid short version or feature version name.
      if (strParts.length === 1) {
        const version = strParts[0]
        const isValidVersion = validateVersion(version)
        if (!isValidVersion) {
          errors.push(`"${version}" is not a valid short version or feature version name`)
        }
      }

      // if length = 2, this should be 'not' followed by a valid short version name.
      if (strParts.length === 2) {
        const [notKeyword, version] = strParts
        const isValidVersion = validateVersion(version)
        const isValid = notKeyword === 'not' && isValidVersion
        if (!isValid) {
          errors.push(`"${cond}" is not a valid conditional`)
        }
      }

      // if length = 3, this should be a range in the format: ghes > 3.0
      // where the first item is `ghes` (currently the only version with numbered releases),
      // the second item is a supported operator, and the third is a supported GHES release.
      if (strParts.length === 3) {
        const [version, operator, release] = strParts
        if (version !== 'ghes') {
          errors.push(
            `Found "${version}" inside "${cond}" with a "${operator}" operator; expected "ghes"`
          )
        }
        if (!allowedVersionOperators.includes(operator)) {
          errors.push(
            `Found a "${operator}" operator inside "${cond}", but "${operator}" is not supported`
          )
        }
        // Check nextNext is one version ahead of next
        if (!isNextVersion(next, nextNext)) {
          errors.push(
            `The nextNext version: "${nextNext} is not one version ahead of the next supported version: "${next}" - check lib/enterprise-server-releases.js`
          )
        }
        // Check that the versions in conditionals are supported
        // versions of GHES or the first deprecated version. Allowing
        // the first deprecated version to exist in code ensures
        // allows us to deprecate the version before removing
        // the old liquid content.
        if (
          !(
            supported.includes(release) ||
            release === next ||
            release === nextNext ||
            deprecated[0] === release
          )
        ) {
          errors.push(
            `Found ${release} inside "${cond}", but ${release} is not a supported GHES release`
          )
        }
      }
    })
  })

  return errors
}

function isNextVersion(v1, v2) {
  const semverNext = semver.coerce(v1)
  const semverNextNext = semver.coerce(v2)
  const semverSupported = []

  supported.forEach((el, i) => {
    semverSupported[i] = semver.coerce(el)
  })
  // Check that the next version is the next version from the supported list first
  const maxVersion = semver.maxSatisfying(semverSupported, '*').raw
  const nextVersionCheck =
    semverNext.raw === semver.inc(maxVersion, 'minor') ||
    semverNext.raw === semver.inc(maxVersion, 'major')
  return (
    nextVersionCheck &&
    (semver.inc(semverNext, 'minor') === semverNextNext.raw ||
      semver.inc(semverNext, 'major') === semverNextNext.raw)
  )
}