const path = require('path')
const slash = require('slash')
const fs = require('fs')
const walk = require('walk-sync')
const matter = require('@github-docs/frontmatter')
const { zip } = require('lodash')
const yaml = require('js-yaml')
const languages = require('../../lib/languages')
const { tags } = require('../../lib/liquid-tags/extended-markdown')

const rootDir = path.join(__dirname, '../..')
const contentDir = path.join(rootDir, 'content')
const reusablesDir = path.join(rootDir, 'data/reusables')
const variablesDir = path.join(rootDir, 'data/variables')

const languageCodes = Object.keys(languages)

// WARNING: Complicated RegExp below!
//
// Things matched by this RegExp:
//  - [link text](link-url)
//  - [link text] (link-url)
//  - [link-definition-ref]: link-url
//  - etc.
//
// Things intentionally NOT matched by this RegExp:
//  - [link text](#link-url)
//  - [link text] (#link-url)
//  - [link-definition-ref]: #link-url
//  - [link text](/link-url)
//  - [link-definition-ref]: /link-url
//  - [link text](https://link-url)
//  - [link-definition-ref]: https://link-url
//  - [link text](mailto:mail-url)
//  - [link-definition-ref]: mailto:mail-url
//  - [link text](tel:phone-url)
//  - [link-definition-ref]: tel:phone-url
//  - [link text]({{ site.data.variables.product_url }})
//  - [link-definition-ref]: {{ site.data.variables.product_url }}
//  - [link text][link-definition-ref]: other text
//  - [link text][link-definition-ref] (other text)
//  - etc.
//
const relativeArticleLinkRegex = /(?=^|[^\]]\s*)\[[^\]]+\](?::\n?[ \t]+|\s*\()(?!\/|#|https?:\/\/|tel:|mailto:|\{[%{]\s*)[^)\s]+(?:(?:\s*[%}]\})?\)|\s+|$)/gm

// Things matched by this RegExp:
//  - [link text](/en/github/blah)
//  - [link text] (https://docs.github.com/ja/github/blah)
//  - [link-definition-ref]: http://help.github.com/es/github/blah
//  - etc.
//
// Things intentionally NOT matched by this RegExp:
//  - [Node.js](https://nodejs.org/en/)
//  - etc.
//
const languageLinkRegex = new RegExp(`(?=^|[^\\]]\\s*)\\[[^\\]]+\\](?::\\n?[ \\t]+|\\s*\\()(?:(?:https?://(?:help|docs|developer)\\.github\\.com)?/(?:${languageCodes.join('|')})(?:/[^)\\s]*)?)(?:\\)|\\s+|$)`, 'gm')

// Things matched by this RegExp:
//  - [link text](/enterprise/2.19/admin/blah)
//  - [link text] (https://docs.github.com/enterprise/11.10.340/admin/blah)
//  - [link-definition-ref]: http://help.github.com/enterprise/2.8/admin/blah
//
// Things intentionally NOT matched by this RegExp:
//  - [link text](https://someservice.com/enterprise/1.0/blah)
//  - [link text](/github/site-policy/enterprise/2.2/admin/blah)
const versionLinkRegEx = /(?=^|[^\]]\s*)\[[^\]]+\](?::\n?[ \t]+|\s*\()(?:(?:https?:\/\/(?:help|docs|developer)\.github\.com)?\/enterprise\/\d+(\.\d+)+(?:\/[^)\s]*)?)(?:\)|\s+|$)/gm

//  - [link text](https://docs.github.com/github/blah)
//  - [link text] (https://help.github.com/github/blah)
//  - [link-definition-ref]: http://developer.github.com/v3/
//  - [link text](//docs.github.com)
//  - etc.
//
// Things intentionally NOT matched by this RegExp:
//  - [link text](/github/blah)
//  - [link text[(https://developer.github.com/changes/2018-02-22-protected-branches-required-signatures/)
//  - etc.
//
const domainLinkRegex = /(?=^|[^\]]\s*)\[[^\]]+\](?::\n?[ \t]+|\s*\()(?:https?:)?\/\/(?:help|docs|developer)\.github\.com(?!\/changes\/)[^)\s]*(?:\)|\s+|$)/gm

// {{ site.data.example.pizza }}
const oldVariableRegex = /{{\s?site\.data\..*}}/g

//  - {{ octicon-plus }}
//  - {{ octicon-plus An example label }}
//
const oldOcticonRegex = /{{\s?octicon-([a-z-]+)(\s[\w\s\d-]+)?\s?}}/g

//  - {{#note}}
//  - {{/note}}
//  - {{ #warning }}
//  - {{ /pizza }}
//
const oldExtendedMarkdownRegex = /{{\s?[#/][a-z-]+\s?}}/g

const relativeArticleLinkErrorText = 'Found unexpected relative article links:'
const languageLinkErrorText = 'Found article links with hard-coded language codes:'
const versionLinkErrorText = 'Found article links with hard-coded version numbers:'
const domainLinkErrorText = 'Found article links with hard-coded domain names:'
const oldVariableErrorText = 'Found article uses old {{ site.data... }} syntax. Use {% data example.data.string %} instead!'
const oldOcticonErrorText = 'Found octicon variables with the old {{ octicon-name }} syntax. Use {% octicon "name" %} instead!'
const oldExtendedMarkdownErrorText = 'Found extended markdown tags with the old {{#note}} syntax. Use {% note %}/{% endnote %} instead!'

describe('lint-files', () => {
  const mdWalkOptions = {
    globs: ['**/*.md'],
    ignore: ['**/README.md'],
    directories: false,
    includeBasePath: true
  }

  const contentMarkdownAbsPaths = walk(contentDir, mdWalkOptions).sort()
  const contentMarkdownRelPaths = contentMarkdownAbsPaths.map(p => slash(path.relative(rootDir, p)))
  const contentMarkdownTuples = zip(contentMarkdownRelPaths, contentMarkdownAbsPaths)

  const reusableMarkdownAbsPaths = walk(reusablesDir, mdWalkOptions).sort()
  const reusableMarkdownRelPaths = reusableMarkdownAbsPaths.map(p => slash(path.relative(rootDir, p)))
  const reusableMarkdownTuples = zip(reusableMarkdownRelPaths, reusableMarkdownAbsPaths)

  describe.each([...contentMarkdownTuples, ...reusableMarkdownTuples])(
    'in "%s"',
    (markdownRelPath, markdownAbsPath) => {
      let content

      beforeAll(async () => {
        const fileContents = await fs.promises.readFile(markdownAbsPath, 'utf8')
        const { content: bodyContent } = matter(fileContents)

        content = bodyContent
      })

      test('relative URLs must start with "/"', async () => {
        const initialMatches = (content.match(relativeArticleLinkRegex) || [])

        // Filter out some very specific false positive matches
        const matches = initialMatches.filter(match => {
          if (markdownRelPath === 'content/github/enforcing-best-practices-with-github-policies/overview.md') {
            if (match === '[A-Z]([a-z]|-)') {
              return false
            }
          } else if (markdownRelPath === 'content/github/enforcing-best-practices-with-github-policies/constraints.md') {
            if (match === '[a-z]([a-z]|-)') {
              return false
            }
          } else if (markdownRelPath === 'content/github/building-a-strong-community/editing-wiki-content.md') {
            if (match === '[Link Text](full-URL-of-wiki-page)') {
              return false
            }
          } else if (markdownRelPath === 'content/admin/configuration/configuring-email-for-notifications.md') {
            if (/^\[\d+\]: (?:connect|disconnect|[0-9A-F]+:)\s*$/.test(match)) {
              return false
            }
          } else if (markdownRelPath === 'content/actions/hosting-your-own-runners/monitoring-and-troubleshooting-self-hosted-runners.md') {
            if (/^\[\d+\]: (?:Starting|Started|√|\d{4}-\d{2}-\d{2})\s*$/.test(match)) {
              return false
            }
          } else if (markdownRelPath === 'content/github/finding-security-vulnerabilities-and-errors-in-your-code/sarif-support-for-code-scanning.md') {
            if (/^\[(?:here|ruleIndex|ruleID)\]\(\d+\)\s*$/.test(match)) {
              return false
            }
          } else if (markdownRelPath === 'content/github/building-a-strong-community/manually-creating-a-single-issue-template-for-your-repository.md') {
            if (match === '[DATE]: [FEATURE ') {
              return false
            }
          } else if (markdownRelPath === 'content/rest/overview/libraries.md') {
            if (
              match === '[pithub-github] ([CPAN][pithub-cpan])' ||
              match === '[net-github-github] ([CPAN][net-github-cpan])'
            ) {
              return false
            }
          } else if (markdownRelPath === 'data/reusables/repositories/relative-links.md') {
            if (match === '[Contribution guidelines for this project](docs/CONTRIBUTING.md)') {
              return false
            }
          }
          return true
        })

        const errorMessage = formatLinkError(relativeArticleLinkErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('URLs must not contain a hard-coded language code', async () => {
        const matches = (content.match(languageLinkRegex) || [])
        const errorMessage = formatLinkError(languageLinkErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('URLs must not contain a hard-coded version number', async () => {
        const initialMatches = (content.match(versionLinkRegEx) || [])

        // Filter out some very specific false positive matches
        const matches = initialMatches.filter(match => {
          if (markdownRelPath === 'content/admin/enterprise-management/migrating-from-github-enterprise-1110x-to-2123.md') {
            return false
          }
          return true
        })

        const errorMessage = formatLinkError(versionLinkErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('URLs must not contain a hard-coded domain name', async () => {
        const matches = (content.match(domainLinkRegex) || [])
        const errorMessage = formatLinkError(domainLinkErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('does not use old site.data variable syntax', async () => {
        const matches = (content.match(oldVariableRegex) || [])
        const matchesWithExample = matches.map(match => {
          const example = match
            .replace(/{{\s?site\.data\.([a-zA-Z0-9-_]+(?:\.[a-zA-Z0-9-_]+)+)\s*}}/g, '{% data $1 %}')
          return `${match} => ${example}`
        })
        const errorMessage = formatLinkError(oldVariableErrorText, matchesWithExample)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('does not use old octicon variable syntax', async () => {
        const matches = (content.match(oldOcticonRegex) || [])
        const errorMessage = formatLinkError(oldOcticonErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('does not use old extended markdown syntax', async () => {
        Object.keys(tags).forEach(tag => {
          const reg = new RegExp(`{{\\s?[#|/]${tag}`, 'g')
          if (reg.test(content)) {
            const matches = (content.match(oldExtendedMarkdownRegex)) || []
            const tagMessage = oldExtendedMarkdownErrorText
              .replace('{{#note}}', `{{#${tag}}}`)
              .replace('{% note %}', `{% ${tag} %}`)
              .replace('{% endnote %}', `{% end${tag} %}`)
            const errorMessage = formatLinkError(tagMessage, matches)
            expect(matches.length, errorMessage).toBe(0)
          }
        })
      })
    }
  )

  // Also test the "data/variables/" YAML files
  const yamlWalkOptions = {
    globs: ['**/*.yml'],
    directories: false,
    includeBasePath: true
  }

  const variableYamlAbsPaths = walk(variablesDir, yamlWalkOptions).sort()
  const variableYamlRelPaths = variableYamlAbsPaths.map(p => path.relative(rootDir, p))
  const variableYamlTuples = zip(variableYamlRelPaths, variableYamlAbsPaths)

  describe.each(variableYamlTuples)(
    'in "%s"',
    (yamlRelPath, yamlAbsPath) => {
      let dictionary

      beforeAll(async () => {
        const fileContents = await fs.promises.readFile(yamlAbsPath, 'utf8')
        dictionary = yaml.safeLoad(fileContents, { filename: yamlRelPath })
      })

      test('relative URLs must start with "/"', async () => {
        const matches = []

        for (const [key, content] of Object.entries(dictionary)) {
          if (typeof content !== 'string') continue
          const valMatches = (content.match(relativeArticleLinkRegex) || [])
          if (valMatches.length > 0) {
            matches.push(...valMatches.map((match) => `Key "${key}": ${match}`))
          }
        }

        const errorMessage = formatLinkError(relativeArticleLinkErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('URLs must not contain a hard-coded language code', async () => {
        const matches = []

        for (const [key, content] of Object.entries(dictionary)) {
          if (typeof content !== 'string') continue
          const valMatches = (content.match(languageLinkRegex) || [])
          if (valMatches.length > 0) {
            matches.push(...valMatches.map((match) => `Key "${key}": ${match}`))
          }
        }

        const errorMessage = formatLinkError(languageLinkErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('URLs must not contain a hard-coded version number', async () => {
        const matches = []

        for (const [key, content] of Object.entries(dictionary)) {
          if (typeof content !== 'string') continue
          const valMatches = (content.match(versionLinkRegEx) || [])
          if (valMatches.length > 0) {
            matches.push(...valMatches.map((match) => `Key "${key}": ${match}`))
          }
        }

        const errorMessage = formatLinkError(versionLinkErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('URLs must not contain a hard-coded domain name', async () => {
        const matches = []

        for (const [key, content] of Object.entries(dictionary)) {
          if (typeof content !== 'string') continue
          const valMatches = (content.match(domainLinkRegex) || [])
          if (valMatches.length > 0) {
            matches.push(...valMatches.map((match) => `Key "${key}": ${match}`))
          }
        }

        const errorMessage = formatLinkError(domainLinkErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('does not use old site.data variable syntax', async () => {
        const matches = []

        for (const [key, content] of Object.entries(dictionary)) {
          if (typeof content !== 'string') continue
          const valMatches = (content.match(oldVariableRegex) || [])
          if (valMatches.length > 0) {
            matches.push(...valMatches.map((match) => {
              const example = match
                .replace(/{{\s?site\.data\.([a-zA-Z0-9-_]+(?:\.[a-zA-Z0-9-_]+)+)\s*}}/g, '{% data $1 %}')
              return `Key "${key}": ${match} => ${example}`
            }))
          }
        }

        const errorMessage = formatLinkError(oldVariableErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('does not use old octicon variable syntax', async () => {
        const matches = []

        for (const [key, content] of Object.entries(dictionary)) {
          if (typeof content !== 'string') continue
          const valMatches = (content.match(oldOcticonRegex) || [])
          if (valMatches.length > 0) {
            matches.push(...valMatches.map((match) => `Key "${key}": ${match}`))
          }
        }

        const errorMessage = formatLinkError(oldOcticonErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })

      test('does not use old extended markdown syntax', async () => {
        const matches = []

        for (const [key, content] of Object.entries(dictionary)) {
          if (typeof content !== 'string') continue
          const valMatches = (content.match(oldExtendedMarkdownRegex) || [])
          if (valMatches.length > 0) {
            matches.push(...valMatches.map((match) => `Key "${key}": ${match}`))
          }
        }

        const errorMessage = formatLinkError(oldExtendedMarkdownErrorText, matches)
        expect(matches.length, errorMessage).toBe(0)
      })
    }
  )
})

function formatLinkError (message, links) {
  return `${message}\n  - ${links.join('\n  - ')}`
}