/* eslint-disable @typescript-eslint/no-unused-vars */

const area = (element) => element.offsetHeight * element.offsetWidth;

function getBiggestElement(selector) {
  const elements = Array.from(document.querySelectorAll(selector));
  const biggest = elements.reduce(
    (max, elem) => (
      area(elem) > area(max) ? elem : max),
    { offsetHeight: 0, offsetWidth: 0 },
  );
  return biggest;
}

/**
 * Generates structural selector (describing element by its DOM tree location).
 *
 * **The generated selector is not guaranteed to be unique!** (In fact, this is
 *    the desired behaviour in here.)
 * @param {HTMLElement} element Element being described.
 * @returns {string} CSS-compliant selector describing the element's location in the DOM tree.
 */
function GetSelectorStructural(element) {
  // Base conditions for the recursive approach.
  if (element.tagName === 'BODY') {
    return 'BODY';
  }
  const selector = element.tagName;
  if (element.parentElement) {
    return `${GetSelectorStructural(element.parentElement)} > ${selector}`;
  }

  return selector;
}

/**
 * Heuristic method to find collections of "interesting" items on the page.
 * @returns {Array<HTMLElement>} A collection of interesting DOM nodes
 *  (online store products, plane tickets, list items... and many more?)
 */
function scrapableHeuristics(maxCountPerPage = 50, minArea = 20000, scrolls = 3, metricType = 'size_deviation') {
  const restoreScroll = (() => {
    const { scrollX, scrollY } = window;
    return () => {
      window.scrollTo(scrollX, scrollY);
    };
  })();

  /**
* @typedef {Array<{x: number, y: number}>} Grid
*/

  /**
 * Returns an array of grid-aligned {x,y} points.
 * @param {number} [granularity=0.005] sets the number of generated points
 *  (the higher the granularity, the more points).
 * @returns {Grid} Array of {x, y} objects.
 */
  function getGrid(startX = 0, startY = 0, granularity = 0.005) {
    const width = window.innerWidth;
    const height = window.innerHeight;

    const out = [];
    for (let x = 0; x < width; x += 1 / granularity) {
      for (let y = 0; y < height; y += 1 / granularity) {
        out.push({ x: startX + x, y: startY + y });
      }
    }
    return out;
  }

  let maxSelector = { selector: 'body', metric: 0 };

  const updateMaximumWithPoint = (point) => {
    const currentElement = document.elementFromPoint(point.x, point.y);
    const selector = GetSelectorStructural(currentElement);

    const elements = Array.from(document.querySelectorAll(selector))
      .filter((element) => area(element) > minArea);

    // If the current selector targets less than three elements,
    // we consider it not interesting (would be a very underwhelming scraper)
    if (elements.length < 3) {
      return;
    }

    let metric = null;

    if (metricType === 'total_area') {
      metric = elements
        .reduce((p, x) => p + area(x), 0);
    } else if (metricType === 'size_deviation') {
      // This could use a proper "statistics" approach... but meh, so far so good!
      const sizes = elements
        .map((element) => area(element));

      metric = (1 - (Math.max(...sizes) - Math.min(...sizes)) / Math.max(...sizes));
    }

    if (metric > maxSelector.metric && elements.length < maxCountPerPage) {
      maxSelector = { selector, metric };
    }
  };

  for (let scroll = 0; scroll < scrolls; scroll += 1) {
    window.scrollTo(0, scroll * window.innerHeight);

    const grid = getGrid();

    grid.forEach(updateMaximumWithPoint);
  }

  restoreScroll();

  let out = Array.from(document.querySelectorAll(maxSelector.selector));

  const different = (x, i, a) => a.findIndex((e) => e === x) === i;
  // as long as we don't merge any two elements by substituing them for their parents,
  // we substitute.
  while (out.map((x) => x.parentElement).every(different)
    && out.forEach((x) => x.parentElement !== null)) {
    out = out.map((x) => x.parentElement ?? x);
  }

  return out;
}

/**
 * Returns a "scrape" result from the current page.
 * @returns {Array<Object>} *Curated* array of scraped information (with sparse rows removed)
 */
// Wrap the entire function in an IIFE (Immediately Invoked Function Expression)
// and attach it to the window object
(function (window) {
  /**
   * Returns a "scrape" result from the current page.
   * @returns {Array<Object>} *Curated* array of scraped information (with sparse rows removed)
   */
  window.scrape = function (selector = null) {
    /**
     * **crudeRecords** contains uncurated rundowns of "scrapable" elements
     * @type {Array<Object>}
     */
    const crudeRecords = (selector
      ? Array.from(document.querySelectorAll(selector))
      : scrapableHeuristics())
      .map((record) => ({
        ...Array.from(record.querySelectorAll('img'))
          .reduce((p, x, i) => {
            let url = null;
            if (x.srcset) {
              const urls = x.srcset.split(', ');
              [url] = urls[urls.length - 1].split(' ');
            }

            /**
               * Contains the largest elements from `srcset` - if `srcset` is not present, contains
               * URL from the `src` attribute
               *
               * If the `src` attribute contains a data url, imgUrl contains `undefined`.
               */
            let imgUrl;
            if (x.srcset) {
              imgUrl = url;
            } else if (x.src.indexOf('data:') === -1) {
              imgUrl = x.src;
            }

            return ({
              ...p,
              ...(imgUrl ? { [`img_${i}`]: imgUrl } : {}),
            });
          }, {}),
        ...record.innerText.split('\n')
          .reduce((p, x, i) => ({
            ...p,
            [`record_${String(i).padStart(4, '0')}`]: x.trim(),
          }), {}),
      }));

    return crudeRecords;
  };

  /**
   * TODO: Simplify.
   * Given an object with named lists of elements,
   *  groups the elements by their distance in the DOM tree.
   * @param {Object.<string, {selector: string, tag: string}>} lists The named lists of HTML elements.
   * @returns {Array.<Object.<string, string>>}
   */
  window.scrapeSchema = function(lists) {
    // Utility functions remain the same
    function omap(object, f, kf = (x) => x) {
      return Object.fromEntries(
        Object.entries(object)
            .map(([k, v]) => [kf(k), f(v)]),
      );
    }

    function ofilter(object, f) {
      return Object.fromEntries(
        Object.entries(object)
            .filter(([k, v]) => f(k, v)),
      );
    }

    function findAllElements(config) {
      // Check if selector contains iframe notation (:>>)
      if (!config.selector.includes(':>>')) {
          return Array.from(document.querySelectorAll(config.selector));
      }
  
      // For iframe traversal, split by iframe boundary marker
      const parts = config.selector.split(':>>').map(s => s.trim());
      let currentElements = [document];
      
      for (let i = 0; i < parts.length; i++) {
        const part = parts[i];
        const nextElements = [];
          
        for (const element of currentElements) {
          try {
            let targets;
            if (i === 0) {
                // First selector is queried from main document
                targets = Array.from(element.querySelectorAll(part))
                    .filter(el => {
                        // Only include iframes if not the last part
                        if (i === parts.length - 1) return true;
                        return el.tagName === 'IFRAME';
                    });
            } else {
                // For subsequent selectors, we need to look inside iframes
                const iframeDocument = element.contentDocument || element.contentWindow?.document;
                if (!iframeDocument) continue;
                
                targets = Array.from(iframeDocument.querySelectorAll(part));
                
                // If this isn't the last part, filter for iframes only
                if (i < parts.length - 1) {
                    targets = targets.filter(el => el.tagName === 'IFRAME');
                }
            }
            nextElements.push(...targets);
          } catch (error) {
            // Handle cross-origin iframe access errors
            console.warn('Cannot access iframe content:', error);
            continue;
          }
        }
          
        if (nextElements.length === 0) return [];
        currentElements = nextElements;
      }
  
      return currentElements;
    }

    // Modified to handle iframe context for URL resolution
    function getElementValue(element, attribute) {
      if (!element) return null;
  
      // Get the base URL for resolving relative URLs
      const baseURL = element.ownerDocument?.location?.href || window.location.origin;
  
      switch (attribute) {
        case 'href': {
            const relativeHref = element.getAttribute('href');
            return relativeHref ? new URL(relativeHref, baseURL).href : null;
        }
        case 'src': {
            const relativeSrc = element.getAttribute('src');
            return relativeSrc ? new URL(relativeSrc, baseURL).href : null;
        }
        case 'innerText':
            return element.innerText?.trim();
        case 'textContent':
            return element.textContent?.trim();
        default:
            return element.getAttribute(attribute) || element.innerText?.trim();
      }
    }

    // Rest of the functions remain largely the same
    function getSeedKey(listObj) {
      const maxLength = Math.max(...Object.values(
          omap(listObj, (x) => findAllElements(x).length)
      ));
      return Object.keys(
          ofilter(listObj, (_, v) => findAllElements(v).length === maxLength)
      )[0];
    }

    function getMBEs(elements) {
      return elements.map((element) => {
          let candidate = element;
          const isUniqueChild = (e) => elements
              .filter((elem) => {
                  // Handle iframe boundaries when checking containment
                  const sameDocument = elem.ownerDocument === e.ownerDocument;
                  return sameDocument && e.parentNode?.contains(elem);
              })
              .length === 1;

          while (candidate && isUniqueChild(candidate)) {
              candidate = candidate.parentNode;
          }

          return candidate;
      });
    }

    // Main scraping logic remains the same
    const seedName = getSeedKey(lists);
    const seedElements = findAllElements(lists[seedName]);
    const MBEs = getMBEs(seedElements);
    
    const mbeResults = MBEs.map((mbe) => omap(
        lists,
        (config) => {
            const elem = findAllElements(config)
                .find((elem) => mbe.contains(elem));
            
            return elem ? getElementValue(elem, config.attribute) : undefined;
        },
        (key) => key
    )) || [];

    // If MBE approach didn't find all elements, try independent scraping
    if (mbeResults.some(result => Object.values(result).some(v => v === undefined))) {
        // Fall back to independent scraping
        const results = [];
        const foundElements = new Map();

        // Find all elements for each selector
        Object.entries(lists).forEach(([key, config]) => {
            const elements = findAllElements(config);
            foundElements.set(key, elements);
        });

        // Create result objects for each found element
        foundElements.forEach((elements, key) => {
            elements.forEach((element, index) => {
                if (!results[index]) {
                    results[index] = {};
                }
                results[index][key] = getElementValue(element, lists[key].attribute);
            });
        });

        return results.filter(result => Object.keys(result).length > 0);
    }

    return mbeResults;
  };

  /**
 * Scrapes multiple lists of similar items based on a template item.
 * @param {Object} config - Configuration object
 * @param {string} config.listSelector - Selector for the list container(s)
 * @param {Object.<string, {selector: string, attribute?: string}>} config.fields - Fields to scrape
 * @param {number} [config.limit] - Maximum number of items to scrape per list (optional)
 * @param {boolean} [config.flexible=false] - Whether to use flexible matching for field selectors
 * @returns {Array.<Array.<Object>>} Array of arrays of scraped items, one sub-array per list
 */
  window.scrapeList = async function ({ listSelector, fields, limit = 10 }) {
    // Helper function to query elements within an iframe
    const queryIframe = (rootElement, selector) => {
        if (!selector.includes(':>>')) {
            return rootElement.querySelector(selector);
        }

        const parts = selector.split(':>>').map(part => part.trim());
        let currentElement = rootElement;

        for (let i = 0; i < parts.length; i++) {
            if (!currentElement) return null;

            // Handle iframe content document
            if (currentElement.tagName === 'IFRAME') {
                try {
                    const iframeDoc = currentElement.contentDocument || currentElement.contentWindow.document;
                    currentElement = iframeDoc.querySelector(parts[i]);
                    continue;
                } catch (e) {
                    console.error('Cannot access iframe content:', e);
                    return null;
                }
            }

            currentElement = currentElement.querySelector(parts[i]);
        }

        return currentElement;
    };

    // Helper function to query all matching elements within iframes
    const queryIframeAll = (rootElement, selector) => {
        if (!selector.includes(':>>')) {
            return rootElement.querySelectorAll(selector);
        }

        const parts = selector.split(':>>').map(part => part.trim());
        let currentElements = [rootElement];
        
        for (const part of parts) {
            const nextElements = [];
            
            for (const element of currentElements) {
                if (element.tagName === 'IFRAME') {
                    try {
                        const iframeDoc = element.contentDocument || element.contentWindow.document;
                        nextElements.push(...iframeDoc.querySelectorAll(part));
                    } catch (e) {
                        console.error('Cannot access iframe content:', e);
                        continue;
                    }
                } else {
                    nextElements.push(...element.querySelectorAll(part));
                }
            }
            
            currentElements = nextElements;
        }
        
        return currentElements;
    };

    // Helper function to extract values from elements
    function extractValue(element, attribute) {
        if (!element) return null;
        
        if (attribute === 'innerText') {
            return element.innerText.trim();
        } else if (attribute === 'innerHTML') {
            return element.innerHTML.trim();
        } else if (attribute === 'src' || attribute === 'href') {
            const attrValue = element.getAttribute(attribute);
            return attrValue ? new URL(attrValue, window.location.origin).href : null;
        }
        return element.getAttribute(attribute);
    }

    // Helper function to find table ancestor elements
    function findTableAncestor(element) {
        let currentElement = element;
        const MAX_DEPTH = 5;
        let depth = 0;
        
        while (currentElement && depth < MAX_DEPTH) {
            if (currentElement.tagName === 'TD') {
                return { type: 'TD', element: currentElement };
            } else if (currentElement.tagName === 'TR') {
                return { type: 'TR', element: currentElement };
            }
            
            // Handle iframe boundary crossing
            if (currentElement.tagName === 'IFRAME') {
                try {
                    currentElement = currentElement.contentDocument.body;
                } catch (e) {
                    return null;
                }
            } else {
                currentElement = currentElement.parentElement;
            }
            depth++;
        }
        return null;
    }

    // Helper function to get cell index
    function getCellIndex(td) {
        let index = 0;
        let sibling = td;
        while (sibling = sibling.previousElementSibling) {
            index++;
        }
        return index;
    }

    // Helper function to check for TH elements
    function hasThElement(row, tableFields) {
        for (const [label, { selector }] of Object.entries(tableFields)) {
            const element = queryIframe(row, selector);
            if (element) {
                let current = element;
                while (current && current !== row) {
                    if (current.tagName === 'TH') {
                        return true;
                    }
                    if (current.tagName === 'IFRAME') {
                        try {
                            current = current.contentDocument.body;
                        } catch (e) {
                            break;
                        }
                    } else {
                        current = current.parentElement;
                    }
                }
            }
        }
        return false;
    }

    // Helper function to filter rows
    function filterRowsBasedOnTag(rows, tableFields) {
        for (const row of rows) {
            if (hasThElement(row, tableFields)) {
                return rows;
            }
        }
        return rows.filter(row => row.getElementsByTagName('TH').length === 0);
    }

    // Class similarity comparison functions
    function calculateClassSimilarity(classList1, classList2) {
        const set1 = new Set(classList1);
        const set2 = new Set(classList2);
        const intersection = new Set([...set1].filter(x => set2.has(x)));
        const union = new Set([...set1, ...set2]);
        return intersection.size / union.size;
    }

    function findSimilarElements(baseElement, similarityThreshold = 0.7) {
        const baseClasses = Array.from(baseElement.classList);
        if (baseClasses.length === 0) return [];
        
        // Include elements from all iframes
        const allElements = [];
        const iframes = document.getElementsByTagName('iframe');
        
        // Add elements from main document
        allElements.push(...document.getElementsByTagName(baseElement.tagName));
        
        // Add elements from each iframe
        for (const iframe of iframes) {
            try {
                const iframeDoc = iframe.contentDocument || iframe.contentWindow.document;
                allElements.push(...iframeDoc.getElementsByTagName(baseElement.tagName));
            } catch (e) {
                console.error('Cannot access iframe content:', e);
            }
        }
        
        return allElements.filter(element => {
            if (element === baseElement) return false;
            const similarity = calculateClassSimilarity(
                baseClasses,
                Array.from(element.classList)
            );
            return similarity >= similarityThreshold;
        });
    }

    // Main scraping logic
    let containers = queryIframeAll(document, listSelector);
    containers = Array.from(containers);

    if (containers.length === 0) return [];

    if (limit > 1 && containers.length === 1) {
        const baseContainer = containers[0];
        const similarContainers = findSimilarElements(baseContainer);
        
        if (similarContainers.length > 0) {
            const newContainers = similarContainers.filter(container => 
                !container.matches(listSelector)
            );
            containers = [...containers, ...newContainers];
        }
    }

    const containerFields = containers.map(() => ({
        tableFields: {},
        nonTableFields: {}
    }));

    // Classify fields
    containers.forEach((container, containerIndex) => {
        for (const [label, field] of Object.entries(fields)) {
            const sampleElement = queryIframe(container, field.selector);
            
            if (sampleElement) {
                const ancestor = findTableAncestor(sampleElement);
                if (ancestor) {
                    containerFields[containerIndex].tableFields[label] = {
                        ...field,
                        tableContext: ancestor.type,
                        cellIndex: ancestor.type === 'TD' ? getCellIndex(ancestor.element) : -1
                    };
                } else {
                    containerFields[containerIndex].nonTableFields[label] = field;
                }
            } else {
                containerFields[containerIndex].nonTableFields[label] = field;
            }
        }
    });

    const tableData = [];
    const nonTableData = [];

    // Process table data
    for (let containerIndex = 0; containerIndex < containers.length; containerIndex++) {
        const container = containers[containerIndex];
        const { tableFields } = containerFields[containerIndex];

        if (Object.keys(tableFields).length > 0) {
            const firstField = Object.values(tableFields)[0];
            const firstElement = queryIframe(container, firstField.selector);
            let tableContext = firstElement;
            
            while (tableContext && tableContext.tagName !== 'TABLE' && tableContext !== container) {
                if (tableContext.tagName === 'IFRAME') {
                    try {
                        tableContext = tableContext.contentDocument.body;
                    } catch (e) {
                        break;
                    }
                } else {
                    tableContext = tableContext.parentElement;
                }
            }

            if (tableContext) {
                const rows = Array.from(tableContext.getElementsByTagName('TR'));
                const processedRows = filterRowsBasedOnTag(rows, tableFields);
                
                for (let rowIndex = 0; rowIndex < Math.min(processedRows.length, limit); rowIndex++) {
                    const record = {};
                    const currentRow = processedRows[rowIndex];
                    
                    for (const [label, { selector, attribute, cellIndex }] of Object.entries(tableFields)) {
                        let element = null;
                        
                        if (cellIndex >= 0) {
                            const td = currentRow.children[cellIndex];
                            if (td) {
                                element = queryIframe(td, selector);
                                
                                if (!element && selector.split(">").pop().includes('td:nth-child')) {
                                    element = td;
                                }

                                if (!element) {
                                    const tagOnlySelector = selector.split('.')[0];
                                    element = queryIframe(td, tagOnlySelector);
                                }
                                
                                if (!element) {
                                    let currentElement = td;
                                    while (currentElement && currentElement.children.length > 0) {
                                        let foundContentChild = false;
                                        for (const child of currentElement.children) {
                                            if (extractValue(child, attribute)) {
                                                currentElement = child;
                                                foundContentChild = true;
                                                break;
                                            }
                                        }
                                        if (!foundContentChild) break;
                                    }
                                    element = currentElement;
                                }
                            }
                        } else {
                            element = queryIframe(currentRow, selector);
                        }
                        
                        if (element) {
                            record[label] = extractValue(element, attribute);
                        }
                    }

                    if (Object.keys(record).length > 0) {
                        tableData.push(record);
                    }
                }
            }
        }
    }

    // Process non-table data
    for (let containerIndex = 0; containerIndex < containers.length; containerIndex++) {
        if (nonTableData.length >= limit) break;

        const container = containers[containerIndex];
        const { nonTableFields } = containerFields[containerIndex];

        if (Object.keys(nonTableFields).length > 0) {
            const record = {};

            for (const [label, { selector, attribute }] of Object.entries(nonTableFields)) {
                const relativeSelector = selector.split(':>>').slice(-1)[0];
                const element = queryIframe(container, relativeSelector);
                
                if (element) {
                    record[label] = extractValue(element, attribute);
                }
            }
                
            if (Object.keys(record).length > 0) {
                nonTableData.push(record);
            }
        }  
    }
      
    // Merge and limit the results
    const scrapedData = [...tableData, ...nonTableData];
    return scrapedData;
  };

  /**
 * Gets all children of the elements matching the listSelector,
 * returning their CSS selectors and innerText.
 * @param {string} listSelector - Selector for the list container(s)
 * @returns {Array.<Object>} Array of objects, each containing the CSS selector and innerText of the children
 */
  window.scrapeListAuto = function (listSelector) {
    const lists = Array.from(document.querySelectorAll(listSelector));

    const results = [];

    lists.forEach(list => {
      const children = Array.from(list.children);

      children.forEach(child => {
        const selectors = [];
        let element = child;

        // Traverse up to gather the CSS selector for the element
        while (element && element !== document) {
          let selector = element.nodeName.toLowerCase();
          if (element.id) {
            selector += `#${element.id}`;
            selectors.push(selector);
            break;
          } else {
            const className = element.className.trim().split(/\s+/).join('.');
            if (className) {
              selector += `.${className}`;
            }
            selectors.push(selector);
            element = element.parentElement;
          }
        }

        results.push({
          selector: selectors.reverse().join(' > '),
          innerText: child.innerText.trim()
        });
      });
    });

    return results;
  };

})(window);