src/lib/extract/helpers/transform-array-to-obj.ts

import isEqual from "lodash/isEqual";

/**
 * Transforms an array of objects into a single object, merging properties with the same name.
 * @param originalSchema - The schema of the original data.
 * @param arrayData - The array of objects to transform.
 * @returns A single object with merged properties.
 */
export function transformArrayToObject(
  originalSchema: any,
  arrayData: any[],
): any {
  if (Object.keys(originalSchema).length == 0) {
    return {};
  }

  const transformedResult: any = {};

  // Function to find the array key in a nested schema
  function findArrayKey(schema: any): string | null {
    for (const key in schema.properties) {
      if (schema.properties[key].type === "array") {
        return key;
      } else if (schema.properties[key].type === "object") {
        const nestedKey = findArrayKey(schema.properties[key]);
        if (nestedKey) {
          return `${key}.${nestedKey}`;
        }
      }
    }
    return null;
  }

  const arrayKeyPath = findArrayKey(originalSchema);
  if (!arrayKeyPath) {
    return arrayData.reduce((acc, item) => {
      for (const key in item) {
        if (!acc[key]) {
          acc[key] = item[key];
        } else if (
          typeof acc[key] === "object" &&
          typeof item[key] === "object"
        ) {
          acc[key] = { ...acc[key], ...item[key] };
        }
      }
      return acc;
    }, {});
  }

  const arrayKeyParts = arrayKeyPath.split(".");
  const arrayKey = arrayKeyParts.pop();
  if (!arrayKey) {
    throw new Error("Array key not found in schema");
  }

  const parentSchema = arrayKeyParts.reduce(
    (schema, key) => schema.properties[key],
    originalSchema,
  );
  const itemSchema = parentSchema.properties[arrayKey].items;
  if (!itemSchema) {
    throw new Error("Item schema not found for array key");
  }

  // Initialize the array in the transformed result
  let currentLevel = transformedResult;
  arrayKeyParts.forEach((part) => {
    if (!currentLevel[part]) {
      currentLevel[part] = {};
    }
    currentLevel = currentLevel[part];
  });
  currentLevel[arrayKey] = [];

  // Helper function to check if an object is already in the array
  function isDuplicateObject(array: any[], obj: any): boolean {
    return array.some((existingItem) => isEqual(existingItem, obj));
  }

  // Helper function to validate if an object follows the schema
  function isValidObject(obj: any, schema: any): boolean {
    return Object.keys(schema.properties).every((key) => {
      return (
        obj.hasOwnProperty(key) &&
        typeof obj[key] === schema.properties[key].type
      );
    });
  }

  // Iterate over each item in the arrayData
  arrayData.forEach((item) => {
    let currentItem = item;
    // Skip null items
    if (currentItem === null) {
      return;
    }
    arrayKeyParts.forEach((part) => {
      if (currentItem && currentItem[part]) {
        currentItem = currentItem[part];
      } else {
        currentItem = null;
      }
    });

    // Skip if we couldn't find the nested path
    if (currentItem === null) {
      return;
    }

    // Copy non-array properties from the parent object
    for (const key in parentSchema.properties) {
      if (
        key !== arrayKey &&
        currentItem.hasOwnProperty(key) &&
        !currentLevel.hasOwnProperty(key)
      ) {
        currentLevel[key] = currentItem[key];
      }
    }

    // Ensure that the currentItem[arrayKey] exists and is an array before mapping
    if (currentItem && currentItem[arrayKey] && Array.isArray(currentItem[arrayKey])) {
      currentItem[arrayKey].forEach((subItem: any) => {
        if (
          typeof subItem === "object" &&
          subItem !== null &&
          isValidObject(subItem, itemSchema)
        ) {
          // For arrays of objects, add only unique objects
          const transformedItem: any = {};
          let hasValidData = false;

          for (const key in itemSchema.properties) {
            if (subItem.hasOwnProperty(key) && subItem[key] !== undefined) {
              transformedItem[key] = subItem[key];
              hasValidData = true;
            }
          }

          if (
            hasValidData &&
            !isDuplicateObject(currentLevel[arrayKey], transformedItem)
          ) {
            currentLevel[arrayKey].push(transformedItem);
          }
        }
      });
    } else {
      console.warn(
        `Expected an array at ${arrayKey}, but found:`,
        currentItem ? currentItem[arrayKey] : 'undefined'
      );

      // create an array if it doesn't exist
      if (currentLevel[arrayKey] === undefined) {
        currentLevel[arrayKey] = [];
      }
    }

    // Handle merging of array properties
    for (const key in parentSchema.properties) {
      if (
        parentSchema.properties[key].type === "array" &&
        currentItem &&
        Array.isArray(currentItem[key])
      ) {
        if (!currentLevel[key]) {
          currentLevel[key] = [];
        }
        currentItem[key].forEach((value: any) => {
          if (
            !currentLevel[key].includes(value) &&
            !isDuplicateObject(currentLevel[arrayKey], value)
          ) {
            currentLevel[key].push(value);
          }
        });
      }
    }
  });

  return transformedResult;
}