frontend/src/lib/visualization-utils.ts

// Color schemes for different visualization types
export const VISUALIZATION_COLORS = {
  // Entity type colors
  entityTypes: {
    person: "#3b82f6",
    organization: "#10b981",
    location: "#f59e0b",
    concept: "#8b5cf6",
    event: "#ef4444",
    default: "#6b7280",
  },

  // Processing method colors
  processingMethods: {
    production: "#059669",
    baseline: "#dc2626",
    hybrid: "#7c3aed",
    sequential: "#ea580c",
    default: "#6b7280",
  },

  // Chart color palettes
  sequential: [
    "#f7fafc",
    "#edf2f7",
    "#e2e8f0",
    "#cbd5e0",
    "#a0aec0",
    "#718096",
    "#4a5568",
    "#2d3748",
    "#1a202c",
  ],

  categorical: [
    "#3b82f6",
    "#10b981",
    "#f59e0b",
    "#8b5cf6",
    "#ef4444",
    "#06b6d4",
    "#84cc16",
    "#f97316",
    "#ec4899",
    "#6366f1",
  ],

  diverging: [
    "#dc2626",
    "#ef4444",
    "#f87171",
    "#fca5a5",
    "#fed7d7",
    "#f3f4f6",
    "#d1fae5",
    "#86efac",
    "#34d399",
    "#10b981",
  ],
};

// Text processing utilities
export function removeStopwords(
  text: string,
  customStopwords: string[] = []
): string {
  const defaultStopwords = [
    "the",
    "be",
    "to",
    "of",
    "and",
    "a",
    "in",
    "that",
    "have",
    "i",
    "it",
    "for",
    "not",
    "on",
    "with",
    "he",
    "as",
    "you",
    "do",
    "at",
    "this",
    "but",
    "his",
    "by",
    "from",
    "they",
    "we",
    "say",
    "her",
    "she",
    "or",
    "an",
    "will",
    "my",
    "one",
    "all",
    "would",
    "there",
    "their",
    "what",
    "so",
    "up",
    "out",
    "if",
    "about",
    "who",
    "get",
    "which",
    "go",
    "me",
    "when",
    "make",
    "can",
    "like",
    "time",
    "no",
    "just",
    "him",
    "know",
    "take",
    "people",
    "into",
    "year",
    "your",
    "good",
    "some",
    "could",
    "them",
    "see",
    "other",
    "than",
    "then",
    "now",
    "look",
    "only",
    "come",
    "its",
    "over",
    "think",
    "also",
    "back",
    "after",
    "use",
    "two",
    "how",
    "our",
    "work",
    "first",
    "well",
    "way",
    "even",
    "new",
    "want",
    "because",
    "any",
    "these",
    "give",
    "day",
    "most",
    "us",
    "is",
    "was",
    "are",
    "been",
    "has",
    "had",
    "were",
    "said",
    "each",
  ];

  const allStopwords = new Set([...defaultStopwords, ...customStopwords]);

  return text
    .toLowerCase()
    .replace(/[^\w\s]/g, " ")
    .split(/\s+/)
    .filter((word) => word.length > 2 && !allStopwords.has(word))
    .join(" ");
}

export function extractKeywords(
  text: string,
  maxKeywords: number = 20
): string[] {
  const processedText = removeStopwords(text);
  const words = processedText.split(/\s+/);

  // Calculate word frequency
  const frequency: Record<string, number> = {};
  words.forEach((word) => {
    frequency[word] = (frequency[word] || 0) + 1;
  });

  // Return top keywords by frequency
  return Object.entries(frequency)
    .sort(([, a], [, b]) => b - a)
    .slice(0, maxKeywords)
    .map(([word]) => word);
}

export function calculateTfIdf(
  documents: string[],
  maxTerms: number = 100
): Array<{ word: string; score: number }> {
  // Calculate TF-IDF scores for term extraction
  const documentWords = documents.map((doc) =>
    removeStopwords(doc).split(/\s+/)
  );
  const vocabulary = new Set(documentWords.flat());

  const tfidfScores: Record<string, number> = {};

  vocabulary.forEach((term) => {
    let tfidfSum = 0;

    documentWords.forEach((docWords) => {
      const tf =
        docWords.filter((word) => word === term).length / docWords.length;
      const df = documentWords.filter((doc) => doc.includes(term)).length;
      const idf = Math.log(documents.length / df);
      tfidfSum += tf * idf;
    });

    tfidfScores[term] = tfidfSum;
  });

  return Object.entries(tfidfScores)
    .sort(([, a], [, b]) => b - a)
    .slice(0, maxTerms)
    .map(([word, score]) => ({ word, score }));
}

// Color utility functions
export function getColorForType(
  type: string,
  colorScheme: "entity" | "processing" = "entity"
): string {
  const schemes = {
    entity: VISUALIZATION_COLORS.entityTypes,
    processing: VISUALIZATION_COLORS.processingMethods,
  };

  return (
    schemes[colorScheme][type as keyof (typeof schemes)[typeof colorScheme]] ||
    schemes[colorScheme].default
  );
}

export function getColorScale(
  count: number,
  type: "sequential" | "categorical" | "diverging" = "categorical"
): string[] {
  const palette = VISUALIZATION_COLORS[type];

  if (count <= palette.length) {
    return palette.slice(0, count);
  }

  // Generate interpolated colors for larger counts
  const step = Math.floor(palette.length / count);
  const colors: string[] = [];

  for (let i = 0; i < count; i++) {
    const index = Math.min(i * step, palette.length - 1);
    colors.push(palette[index] || "#6b7280");
  }

  return colors;
}

export function hexToRgba(hex: string, alpha: number = 1): string {
  const r = parseInt(hex.slice(1, 3), 16);
  const g = parseInt(hex.slice(3, 5), 16);
  const b = parseInt(hex.slice(5, 7), 16);

  return `rgba(${r}, ${g}, ${b}, ${alpha})`;
}

// Text analysis utilities
export function analyzeTextReadability(text: string): {
  readingTime: number;
  complexity: number;
  wordCount: number;
  sentenceCount: number;
  avgWordsPerSentence: number;
  avgSyllablesPerWord: number;
} {
  const words = text.split(/\s+/).filter((word) => word.length > 0);
  const sentences = text.split(/[.!?]+/).filter((s) => s.trim().length > 0);

  const wordCount = words.length;
  const sentenceCount = sentences.length;
  const avgWordsPerSentence = wordCount / sentenceCount;

  // Simple syllable counting (approximation)
  const avgSyllablesPerWord =
    words.reduce((sum, word) => {
      const syllables = word
        .toLowerCase()
        .replace(/[^a-z]/g, "")
        .replace(/[aeiou]{2,}/g, "a")
        .match(/[aeiou]/g);
      return sum + (syllables ? syllables.length : 1);
    }, 0) / wordCount;

  // Flesch-Kincaid Grade Level (simplified)
  const complexity = Math.max(
    0,
    Math.min(
      100,
      206.835 - 1.015 * avgWordsPerSentence - 84.6 * avgSyllablesPerWord
    )
  );

  // Reading time (200 words per minute)
  const readingTime = Math.ceil(wordCount / 200);

  return {
    readingTime,
    complexity,
    wordCount,
    sentenceCount,
    avgWordsPerSentence,
    avgSyllablesPerWord,
  };
}

// Data transformation utilities
export function normalizeValue(
  value: number,
  min: number,
  max: number
): number {
  return (value - min) / (max - min);
}

export function scaleValue(
  value: number,
  oldMin: number,
  oldMax: number,
  newMin: number,
  newMax: number
): number {
  return newMin + ((value - oldMin) * (newMax - newMin)) / (oldMax - oldMin);
}

export function formatNumber(num: number, decimals: number = 0): string {
  if (num >= 1000000) {
    return (num / 1000000).toFixed(decimals) + "M";
  } else if (num >= 1000) {
    return (num / 1000).toFixed(decimals) + "K";
  } else {
    return num.toFixed(decimals);
  }
}

export function formatPercentage(value: number, total: number): string {
  return `${((value / total) * 100).toFixed(1)}%`;
}

// Debounce utility for performance
export function debounce<T extends (...args: any[]) => void>(
  func: T,
  delay: number
): (...args: Parameters<T>) => void {
  let timeoutId: NodeJS.Timeout;

  return (...args: Parameters<T>) => {
    clearTimeout(timeoutId);
    timeoutId = setTimeout(() => func(...args), delay);
  };
}

// DOM utilities for visualization
export function getElementDimensions(element: HTMLElement | null): {
  width: number;
  height: number;
} {
  if (!element) return { width: 0, height: 0 };

  const rect = element.getBoundingClientRect();
  return {
    width: rect.width,
    height: rect.height,
  };
}

export function createSvgElement(width: number, height: number): SVGSVGElement {
  const svg = document.createElementNS("http://www.w3.org/2000/svg", "svg");
  svg.setAttribute("width", width.toString());
  svg.setAttribute("height", height.toString());
  svg.setAttribute("viewBox", `0 0 ${width} ${height}`);
  return svg;
}

// Accessibility utilities
export function generateAccessibleLabel(
  chartType: string,
  dataPoints: number,
  summary?: string
): string {
  const baseLabel = `${chartType} with ${dataPoints} data points`;
  return summary ? `${baseLabel}. ${summary}` : baseLabel;
}

export function getContrastColor(backgroundColor: string): string {
  // Simple contrast color calculation
  const hex = backgroundColor.replace("#", "");
  const r = parseInt(hex.substr(0, 2), 16);
  const g = parseInt(hex.substr(2, 2), 16);
  const b = parseInt(hex.substr(4, 2), 16);

  const brightness = (r * 299 + g * 587 + b * 114) / 1000;
  return brightness > 128 ? "#000000" : "#ffffff";
}