import fs from 'node:fs'
import path, { normalize, sep } from 'node:path'
import { cleanJsonText } from '../utils.js'

function extractPlaceholders(str) {
  const matches = str.match(/\{\{\w+\}\}/g) || []
  return matches.map(m => m.slice(2, -2)).sort()
}

function extractTagMarkers(str) {
  const matches = Array.from(str.matchAll(/<\/?([A-Z][\w-]*)\b[^>]*>/gi))
  const markers = matches.map((match) => {
    const fullMatch = match[0]
    const name = match[1]
    const isClosing = fullMatch.startsWith('</')
    const isSelfClosing = !isClosing && fullMatch.endsWith('/>')

    if (isClosing)
      return `close:${name}`
    if (isSelfClosing)
      return `self:${name}`
    return `open:${name}`
  })

  return markers.sort()
}

function formatTagMarker(marker) {
  if (marker.startsWith('close:'))
    return marker.slice('close:'.length)
  if (marker.startsWith('self:'))
    return marker.slice('self:'.length)
  return marker.slice('open:'.length)
}

function arraysEqual(arr1, arr2) {
  if (arr1.length !== arr2.length)
    return false
  return arr1.every((val, i) => val === arr2[i])
}

function uniqueSorted(items) {
  return Array.from(new Set(items)).sort()
}

function getJsonLiteralValue(node) {
  if (!node)
    return undefined
  return node.type === 'JSONLiteral' ? node.value : undefined
}

function buildPlaceholderMessage(key, englishPlaceholders, currentPlaceholders) {
  const missing = englishPlaceholders.filter(p => !currentPlaceholders.includes(p))
  const extra = currentPlaceholders.filter(p => !englishPlaceholders.includes(p))

  const details = []
  if (missing.length > 0)
    details.push(`missing {{${missing.join('}}, {{')}}}`)
  if (extra.length > 0)
    details.push(`extra {{${extra.join('}}, {{')}}}`)

  return `Placeholder mismatch with en-US in "${key}": ${details.join('; ')}. `
    + `Expected: {{${englishPlaceholders.join('}}, {{') || 'none'}}}`
}

function buildTagMessage(key, englishTagMarkers, currentTagMarkers) {
  const missing = englishTagMarkers.filter(p => !currentTagMarkers.includes(p))
  const extra = currentTagMarkers.filter(p => !englishTagMarkers.includes(p))

  const details = []
  if (missing.length > 0)
    details.push(`missing ${uniqueSorted(missing.map(formatTagMarker)).join(', ')}`)
  if (extra.length > 0)
    details.push(`extra ${uniqueSorted(extra.map(formatTagMarker)).join(', ')}`)

  return `Trans tag mismatch with en-US in "${key}": ${details.join('; ')}. `
    + `Expected: ${uniqueSorted(englishTagMarkers.map(formatTagMarker)).join(', ') || 'none'}`
}

export default {
  meta: {
    type: 'problem',
    docs: {
      description: 'Ensure placeholders and Trans tags in translations match the en-US source',
    },
  },
  create(context) {
    const state = {
      enabled: false,
      englishJson: null,
    }

    function isTopLevelProperty(node) {
      const objectNode = node.parent
      if (!objectNode || objectNode.type !== 'JSONObjectExpression')
        return false
      const expressionNode = objectNode.parent
      return !!expressionNode
        && (expressionNode.type === 'JSONExpressionStatement'
          || expressionNode.type === 'Program'
          || expressionNode.type === 'JSONProgram')
    }

    return {
      Program(node) {
        const { filename } = context

        if (!filename.endsWith('.json'))
          return

        const parts = normalize(filename).split(sep)
        const jsonFile = parts.at(-1)
        const lang = parts.at(-2)

        if (lang === 'en-US')
          return

        state.enabled = true

        try {
          const englishFilePath = path.join(path.dirname(filename), '..', 'en-US', jsonFile ?? '')
          const englishText = fs.readFileSync(englishFilePath, 'utf8')
          state.englishJson = JSON.parse(cleanJsonText(englishText))
        }
        catch (error) {
          state.enabled = false
          context.report({
            node,
            message: `Error parsing JSON: ${error instanceof Error ? error.message : String(error)}`,
          })
        }
      },
      JSONProperty(node) {
        if (!state.enabled)
          return

        if (!state.englishJson || !isTopLevelProperty(node))
          return

        const key = node.key.value ?? node.key.name
        if (!key)
          return

        if (!Object.prototype.hasOwnProperty.call(state.englishJson, key))
          return

        const currentNode = node.value ?? node
        const currentValue = getJsonLiteralValue(currentNode)
        const englishValue = state.englishJson[key]

        if (typeof currentValue !== 'string' || typeof englishValue !== 'string')
          return

        const currentPlaceholders = extractPlaceholders(currentValue)
        const englishPlaceholders = extractPlaceholders(englishValue)
        const currentTagMarkers = extractTagMarkers(currentValue)
        const englishTagMarkers = extractTagMarkers(englishValue)

        if (!arraysEqual(currentPlaceholders, englishPlaceholders)) {
          context.report({
            node: currentNode,
            message: buildPlaceholderMessage(key, englishPlaceholders, currentPlaceholders),
          })
        }

        if (!arraysEqual(currentTagMarkers, englishTagMarkers)) {
          context.report({
            node: currentNode,
            message: buildTagMessage(key, englishTagMarkers, currentTagMarkers),
          })
        }
      },
    }
  },
}