/**
 * Image Context Detector
 *
 * Deterministically evaluates whether a user prompt requests explanatory/learning content
 * combined with visual materials (images, diagrams, pictures, visual aids, etc.) for a topic.
 *
 * Intent combination required:
 *   [Explanation / Learning Intent] + [Visual Material Intent] + [Topic]
 */

const EXPLANATION_INTENT_PATTERN =
  /\b(?:explain|explaining|explanation|teach|teaching|understand|understanding|walk(?:\s+me)?\s+through|break(?:\s+it|\s+this|\s+that)?\s+down|breaking\s+down|learn|learning|clarify|demystify|illustrate|describe|overview|deep\s+dive|how\s+does\s+.+?\s+work|what\s+is\s+.+?\??)\b/i;

const VISUAL_INTENT_PATTERN =
  /\b(?:visually|images?|pics?|pictures?|photos?|diagrams?|figures?|illustrations?|visuals?|visual\s+examples?|visual\s+aids?|visual\s+materials?|visual\s+representations?|infographics?|charts?|flowcharts?|schematics?|drawings?)\b/i;

const VISUAL_CONNECTORS_PATTERN =
  /\b(?:with|using|through|via|accompanied\s+by|including|supported\s+by|featuring|supplemented\s+with|utilizing|showing)\b/i;

const PURE_IMAGE_SEARCH_PATTERN =
  /^(?:show\s+me|find|search\s+for|get|fetch|display|look\s+up|bring\s+up|give\s+me|can\s+you\s+(?:find|show|get)|please\s+(?:show|find))\s+(?:images?|pictures?|pics?|photos?|diagrams?|figures?|illustrations?|drawings?|charts?|schematics?|visuals?)\s+(?:of|for|about|on)\s+[\w\s-]+[?!.]?$/i;

const NON_TOPIC_WORDS = new RegExp(
  `^(?:me|us|it|this|that|them|with|using|through|via|visually|and|or|a|an|the|to|for|on|images?|pictures?|pics?|photos?|diagrams?|figures?|illustrations?|visuals?|visual\\s+examples?|visual\\s+aids?|charts?|schematics?|\\s)*$`,
  "i"
);

function isRealTopic(text: string): boolean {
  const trimmed = text.trim();
  if (trimmed.length < 2) return false;
  return !NON_TOPIC_WORDS.test(trimmed);
}

function extractTopicSubject(text: string): { hasTopic: boolean; topic?: string } {
  const sentences = text.split(/[?.!]/).map(s => s.trim()).filter(s => s.length > 0);
  if (sentences.length > 1) {
    for (const sentence of sentences) {
      const topicMatch = sentence.match(/\b(?:what\s+is|how\s+does|about|regarding|on)\s+([a-z0-9\s-]+)/i);
      if (topicMatch && isRealTopic(topicMatch[1])) {
        return { hasTopic: true, topic: topicMatch[1].trim() };
      }
    }
  }

  const inlineMatch = text.match(
    /\b(?:explain|explaining|teach|teaching|understand|understanding|walk(?:\s+me)?\s+through|break(?:\s+it|\s+this|\s+that)?\s+down|learn|learning|clarify|demystify|illustrate|describe)\s+([\w\s,-]+?)\s+(?:with|using|through|via|accompanied\s+by|including|supported\s+by|featuring|supplemented\s+with|utilizing|showing|visually)\b/i
  );
  if (inlineMatch && isRealTopic(inlineMatch[1])) {
    return { hasTopic: true, topic: inlineMatch[1].trim() };
  }

  const visualFirstMatch = text.match(
    new RegExp(
      `\\b(?:using|with|via|through|showing|provide|providing|use|include|including|show)\\s+[\\w\\s,-]*?\\b(?:${VISUAL_INTENT_PATTERN.source})\\b\\s*(?:,?\\s*while|,?\\s*to|,?\\s*for|,?\\s*and|,?\\s*)\\s*(?:explain|explaining|teach|teaching|understand|understanding|walk(?:\\s+me)?\\s+through|break(?:\\s+down)?|clarify|illustrate|describe)\\s+([\\w\\s,-]+)`,
      "i"
    )
  );
  if (visualFirstMatch && isRealTopic(visualFirstMatch[1])) {
    return { hasTopic: true, topic: visualFirstMatch[1].trim() };
  }

  const suffixMatch = text.match(
    new RegExp(
      `\\b(?:explain|teach|understand|illustrate|describe)\\s+(?:with|using|through|via)\\s+[\\w\\s,-]*?\\b(?:${VISUAL_INTENT_PATTERN.source})\\b\\s+([\\w\\s,-]+)`,
      "i"
    )
  );
  if (suffixMatch && isRealTopic(suffixMatch[1])) {
    return { hasTopic: true, topic: suffixMatch[1].trim() };
  }

  return { hasTopic: false };
}

export function requiresImageContext(userText: string, requestId?: string): boolean {
  const text = typeof userText === "string" ? userText.trim() : "";

  const expMatch = text ? EXPLANATION_INTENT_PATTERN.exec(text) : null;
  const hasExplanationIntent = expMatch !== null;

  const visMatch = text ? VISUAL_INTENT_PATTERN.exec(text) : null;
  const hasVisualIntent = visMatch !== null;

  const topicRes = text ? extractTopicSubject(text) : { hasTopic: false };

  const isPureImageSearch = text ? PURE_IMAGE_SEARCH_PATTERN.test(text) && !hasExplanationIntent : false;

  const hasVisuallyAdverb = text ? /\bvisually\b/i.test(text) : false;

  const hasConnectedVisual = text
    ? new RegExp(
        `(?:${VISUAL_CONNECTORS_PATTERN.source})\\s+[\\w\\s,-]*?${VISUAL_INTENT_PATTERN.source}`,
        "i"
      ).test(text)
    : false;

  const hasVisualAction = text
    ? new RegExp(
        `\\b(?:use|using|include|including|provide|providing|add|show|with|via)\\s+[\\w\\s,-]*?\\b(?:${VISUAL_INTENT_PATTERN.source})\\b`,
        "i"
      ).test(text)
    : false;

  return (
    text.length > 0 &&
    hasExplanationIntent &&
    hasVisualIntent &&
    topicRes.hasTopic &&
    !isPureImageSearch &&
    (hasVisuallyAdverb || hasConnectedVisual || hasVisualAction)
  );
}

/**
 * Image Context Detector
 *
 * Deterministically evaluates whether a user prompt requests explanatory/learning content
 * combined with visual materials (images, diagrams, pictures, visual aids, etc.) for a topic.
 *
 * Intent combination required:
 *   [Explanation / Learning Intent] + [Visual Material Intent] + [Topic]
 */

const EXPLANATION_INTENT_PATTERN =
  /\b(?:explain|explaining|explanation|teach|teaching|understand|understanding|walk(?:\s+me)?\s+through|break(?:\s+it|\s+this|\s+that)?\s+down|breaking\s+down|learn|learning|clarify|demystify|illustrate|describe|overview|deep\s+dive|how\s+does\s+.+?\s+work|what\s+is\s+.+?\??)\b/i;

const VISUAL_INTENT_PATTERN =
  /\b(?:visually|images?|pics?|pictures?|photos?|diagrams?|figures?|illustrations?|visuals?|visual\s+examples?|visual\s+aids?|visual\s+materials?|visual\s+representations?|infographics?|charts?|flowcharts?|schematics?|drawings?)\b/i;

const VISUAL_CONNECTORS_PATTERN =
  /\b(?:with|using|through|via|accompanied\s+by|including|supported\s+by|featuring|supplemented\s+with|utilizing|showing)\b/i;

const PURE_IMAGE_SEARCH_PATTERN =
  /^(?:show\s+me|find|search\s+for|get|fetch|display|look\s+up|bring\s+up|give\s+me|can\s+you\s+(?:find|show|get)|please\s+(?:show|find))\s+(?:images?|pictures?|pics?|photos?|diagrams?|figures?|illustrations?|drawings?|charts?|schematics?|visuals?)\s+(?:of|for|about|on)\s+[\w\s-]+[?!.]?$/i;

const NON_TOPIC_WORDS = new RegExp(
  `^(?:me|us|it|this|that|them|with|using|through|via|visually|and|or|a|an|the|to|for|on|images?|pictures?|pics?|photos?|diagrams?|figures?|illustrations?|visuals?|visual\\s+examples?|visual\\s+aids?|charts?|schematics?|\\s)*$`,
  "i"
);

function isRealTopic(text: string): boolean {
  const trimmed = text.trim();
  if (trimmed.length < 2) return false;
  return !NON_TOPIC_WORDS.test(trimmed);
}

function extractTopicSubject(text: string): { hasTopic: boolean; topic?: string } {
  const sentences = text.split(/[?.!]/).map(s => s.trim()).filter(s => s.length > 0);
  if (sentences.length > 1) {
    for (const sentence of sentences) {
      const topicMatch = sentence.match(/\b(?:what\s+is|how\s+does|about|regarding|on)\s+([a-z0-9\s-]+)/i);
      if (topicMatch && isRealTopic(topicMatch[1])) {
        return { hasTopic: true, topic: topicMatch[1].trim() };
      }
    }
  }

  const inlineMatch = text.match(
    /\b(?:explain|explaining|teach|teaching|understand|understanding|walk(?:\s+me)?\s+through|break(?:\s+it|\s+this|\s+that)?\s+down|learn|learning|clarify|demystify|illustrate|describe)\s+([\w\s,-]+?)\s+(?:with|using|through|via|accompanied\s+by|including|supported\s+by|featuring|supplemented\s+with|utilizing|showing|visually)\b/i
  );
  if (inlineMatch && isRealTopic(inlineMatch[1])) {
    return { hasTopic: true, topic: inlineMatch[1].trim() };
  }

  const visualFirstMatch = text.match(
    new RegExp(
      `\\b(?:using|with|via|through|showing|provide|providing|use|include|including|show)\\s+[\\w\\s,-]*?\\b(?:${VISUAL_INTENT_PATTERN.source})\\b\\s*(?:,?\\s*while|,?\\s*to|,?\\s*for|,?\\s*and|,?\\s*)\\s*(?:explain|explaining|teach|teaching|understand|understanding|walk(?:\\s+me)?\\s+through|break(?:\\s+down)?|clarify|illustrate|describe)\\s+([\\w\\s,-]+)`,
      "i"
    )
  );
  if (visualFirstMatch && isRealTopic(visualFirstMatch[1])) {
    return { hasTopic: true, topic: visualFirstMatch[1].trim() };
  }

  const suffixMatch = text.match(
    new RegExp(
      `\\b(?:explain|teach|understand|illustrate|describe)\\s+(?:with|using|through|via)\\s+[\\w\\s,-]*?\\b(?:${VISUAL_INTENT_PATTERN.source})\\b\\s+([\\w\\s,-]+)`,
      "i"
    )
  );
  if (suffixMatch && isRealTopic(suffixMatch[1])) {
    return { hasTopic: true, topic: suffixMatch[1].trim() };
  }

  return { hasTopic: false };
}

export function requiresImageContext(userText: string, requestId?: string): boolean {
  const text = typeof userText === "string" ? userText.trim() : "";

  const expMatch = text ? EXPLANATION_INTENT_PATTERN.exec(text) : null;
  const hasExplanationIntent = expMatch !== null;

  const visMatch = text ? VISUAL_INTENT_PATTERN.exec(text) : null;
  const hasVisualIntent = visMatch !== null;

  const topicRes = text ? extractTopicSubject(text) : { hasTopic: false };

  const isPureImageSearch = text ? PURE_IMAGE_SEARCH_PATTERN.test(text) && !hasExplanationIntent : false;

  const hasVisuallyAdverb = text ? /\bvisually\b/i.test(text) : false;

  const hasConnectedVisual = text
    ? new RegExp(
        `(?:${VISUAL_CONNECTORS_PATTERN.source})\\s+[\\w\\s,-]*?${VISUAL_INTENT_PATTERN.source}`,
        "i"
      ).test(text)
    : false;

  const hasVisualAction = text
    ? new RegExp(
        `\\b(?:use|using|include|including|provide|providing|add|show|with|via)\\s+[\\w\\s,-]*?\\b(?:${VISUAL_INTENT_PATTERN.source})\\b`,
        "i"
      ).test(text)
    : false;

  return (
    text.length > 0 &&
    hasExplanationIntent &&
    hasVisualIntent &&
    topicRes.hasTopic &&
    !isPureImageSearch &&
    (hasVisuallyAdverb || hasConnectedVisual || hasVisualAction)
  );
}