import { detectPassiveVoice } from './passiveVoice'

const WEASEL_PATTERN = /\b(very|quite|rather|fairly|really|just|basically|actually|literally|clearly|obviously|simply|absolutely|totally|completely|certainly|probably|mostly|nearly|almost|somewhat|arguably|undeniably|remarkably|incredibly|extremely|highly)\b/gi

export interface PolishDimension {
  label: string
  score: number  // 0–100
  issueCount: number
}

export interface PolishScore {
  overall: number
  dimensions: {
    passiveVoice: PolishDimension
    weaselWords: PolishDimension
    sentenceRhythm: PolishDimension
    wordVariety: PolishDimension
    dialogueTags: PolishDimension
  }
}

// Score a rate (issues per 1000 words): 0 issues = 100, penalises linearly up to `cap`
function rateScore(issueCount: number, wordCount: number, cap: number): number {
  if (wordCount === 0) return 100
  const rate = (issueCount / wordCount) * 1000
  return Math.max(0, Math.round(100 - (rate / cap) * 100))
}

function stripMarkdown(text: string): string {
  return text
    .replace(/^#{1,6}\s+/gm, '')   // headings
    .replace(/\*\*?|__?/g, '')     // bold/italic
    .replace(/\[([^\]]+)\]\([^)]+\)/g, '$1') // links
    .replace(/`[^`]+`/g, '')       // inline code
    .replace(/^>\s+/gm, '')        // blockquotes
}

function countWordsIn(text: string): number {
  const t = text.trim()
  return t === '' ? 0 : t.split(/\s+/).length
}

function splitSentences(text: string): string[] {
  return text
    .split(/(?<=[.!?])\s+/)
    .map(s => s.trim())
    .filter(s => s.length > 0)
}

// Sentence rhythm: coefficient of variation of sentence lengths (higher variance = better rhythm)
function sentenceRhythmScore(text: string): { score: number; issueCount: number } {
  const sentences = splitSentences(text)
  if (sentences.length < 3) return { score: 100, issueCount: 0 }

  const lengths = sentences.map(s => s.split(/\s+/).length)
  const mean = lengths.reduce((a, b) => a + b, 0) / lengths.length
  const variance = lengths.reduce((a, b) => a + (b - mean) ** 2, 0) / lengths.length
  const stdDev = Math.sqrt(variance)
  const cv = mean > 0 ? stdDev / mean : 0

  // Count "monotonous runs": 3+ consecutive sentences within 2 words of each other in length
  let runsCount = 0
  let runLen = 1
  for (let i = 1; i < lengths.length; i++) {
    if (Math.abs(lengths[i] - lengths[i - 1]) <= 2) {
      runLen++
      if (runLen === 3) runsCount++
    } else {
      runLen = 1
    }
  }

  // cv >= 0.6 = great rhythm; 0.3 = mediocre; < 0.3 = monotonous
  const score = Math.min(100, Math.round((cv / 0.6) * 100))
  return { score, issueCount: runsCount }
}

// Word variety: type-token ratio in sliding windows of 100 words
function wordVarietyScore(text: string): { score: number; issueCount: number } {
  const words = text.toLowerCase().match(/\b[a-z']+\b/g) ?? []
  if (words.length < 20) return { score: 100, issueCount: 0 }

  const WINDOW = 100
  const SKIP_WORDS = new Set(['the','a','an','and','or','but','in','on','at','to','for','of','with','is','was','are','were','it','he','she','they','i','you','we','be','been','being','that','this','those','these','have','has','had','do','did','does','not','so','as','if','by','from','into','than','then','when','where','who','which','what','his','her','their','its','my','your','our','up','out','about','after','before','all','some','one','no','more','also'])

  const contentWords = words.filter(w => !SKIP_WORDS.has(w))
  if (contentWords.length < 20) return { score: 100, issueCount: 0 }

  const ttrs: number[] = []
  for (let i = 0; i + WINDOW <= contentWords.length; i += Math.floor(WINDOW / 2)) {
    const window = contentWords.slice(i, i + WINDOW)
    const unique = new Set(window).size
    ttrs.push(unique / window.length)
  }
  const avgTTR = ttrs.reduce((a, b) => a + b, 0) / ttrs.length

  // TTR >= 0.7 = rich; 0.4 = acceptable; < 0.4 = repetitive
  const score = Math.min(100, Math.max(0, Math.round(((avgTTR - 0.4) / 0.3) * 100)))

  // Count repeated content words within 50-word windows
  let repeatedCount = 0
  for (let i = 0; i + 50 <= contentWords.length; i += 25) {
    const window = contentWords.slice(i, i + 50)
    const counts = new Map<string, number>()
    for (const w of window) counts.set(w, (counts.get(w) ?? 0) + 1)
    for (const [, count] of counts) if (count >= 3) repeatedCount++
  }

  return { score, issueCount: repeatedCount }
}

// Dialogue tag quality: penalise said-bookisms and adverbs on tags
const SAID_BOOKISMS = /\b(hissed|snapped|exclaimed|barked|spat|snarled|growled|shrieked|whined|croaked|breathed|murmured)\b/gi
const ADV_TAG = /\b(said|asked|replied|whispered)\s+\w+ly\b/gi

function dialogueTagScore(text: string, wordCount: number): { score: number; issueCount: number } {
  const bookisms = (text.match(SAID_BOOKISMS) ?? []).length
  const advTags = (text.match(ADV_TAG) ?? []).length
  const total = bookisms + advTags
  return { score: rateScore(total, wordCount, 8), issueCount: total }
}

export function computePolishScore(rawText: string): PolishScore {
  const text = stripMarkdown(rawText)
  const wordCount = countWordsIn(text)

  const passiveIssues = wordCount > 10 ? detectPassiveVoice(text).length : 0
  const weaselIssues = wordCount > 10 ? (text.match(WEASEL_PATTERN) ?? []).length : 0

  const passive: PolishDimension = {
    label: 'Passive voice',
    score: rateScore(passiveIssues, wordCount, 12),
    issueCount: passiveIssues
  }

  const weasel: PolishDimension = {
    label: 'Weasel words',
    score: rateScore(weaselIssues, wordCount, 10),
    issueCount: weaselIssues
  }

  const rhythmResult = sentenceRhythmScore(text)
  const rhythm: PolishDimension = {
    label: 'Sentence rhythm',
    score: rhythmResult.score,
    issueCount: rhythmResult.issueCount
  }

  const varietyResult = wordVarietyScore(text)
  const variety: PolishDimension = {
    label: 'Word variety',
    score: varietyResult.score,
    issueCount: varietyResult.issueCount
  }

  const dialogueResult = dialogueTagScore(text, wordCount)
  const dialogue: PolishDimension = {
    label: 'Dialogue tags',
    score: dialogueResult.score,
    issueCount: dialogueResult.issueCount
  }

  const weights = { passive: 0.2, weasel: 0.2, rhythm: 0.25, variety: 0.2, dialogue: 0.15 }
  const overall = Math.round(
    passive.score * weights.passive +
    weasel.score * weights.weasel +
    rhythm.score * weights.rhythm +
    variety.score * weights.variety +
    dialogue.score * weights.dialogue
  )

  return {
    overall,
    dimensions: {
      passiveVoice: passive,
      weaselWords: weasel,
      sentenceRhythm: rhythm,
      wordVariety: variety,
      dialogueTags: dialogue
    }
  }
}