/* ------------------------------------------------------------------------------------

  DataCraft - MIT License - Hexagon <hexagon@56k.guru>

  LINQ-like JavaScript object query library. No dependencies. Works in all environments.

  ------------------------------------------------------------------------------------

  License:

	Copyright (c) 2022 Hexagon <hexagon@56k.guru>

	Permission is hereby granted, free of charge, to any person obtaining a copy
	of this software and associated documentation files (the "Software"), to deal
	in the Software without restriction, including without limitation the rights
	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	copies of the Software, and to permit persons to whom the Software is
	furnished to do so, subject to the following conditions:
	The above copyright notice and this permission notice shall be included in
	all copies or substantial portions of the Software.
	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	THE SOFTWARE.

  ------------------------------------------------------------------------------------  */

import { clone } from "./clone.js";
import { validate } from "./validate.js";

/**
 * Creates a new DataSet.
 * @class
 */
class DataSet {

	/**
     * DataSet entrypoint
     * 
     * @constructor
     * @param {object} [options] - Optional options
     * @returns {DataSet}
     */
	constructor(options) {

		this.entries = [];

		// Handle options with defaults and ovverrides
		this.options = {
			allowedFields: null,
			requiredFields: null 
		};
		if (options) {
			validate(options, Object.keys(this.options));
			this.options = clone(options, this.options);
		}

	}

	/* DataSet operations */
	insert(inData) {
		if ( Array.isArray(inData) ) {
			inData.forEach((v) => {
				if (this.options.allowedFields || this.options.requiredFields) {
					validate(v, this.options.allowedFields, this.options.requiredFields);
				}
				this.entries.push(v);
			});
		} else {
			throw new TypeError("DataSet: Parameter to insert must be an array.");
		}
		return this;
	}

	update(o, whereFn) {
		// Validate input
		if (this.options.allowedFields || this.options.requiredFields) {
			validate(o, this.options.allowedFields, this.options.requiredFields);
		}
		this.toArray(whereFn).forEach((e) => {
			let oCopy = clone(o, e);
			e = oCopy;
		});
		return this;
	}

	drop(fieldName) {
		this.entries.forEach(e => delete e[fieldName]);
		return this;
	}

	/* Relation operations */
	join(oDs, target, conditionCb) {
		// Matches
		this.entries.forEach((localObj) => {
			const matches = [];
			oDs.entries.forEach((remoteObj) => {
				if (conditionCb(localObj, remoteObj)) {
					matches.push(remoteObj);
				}
			});
			localObj[target] = matches;
		});

		return this;
	}
	joinFirst(oDs, target, conditionCb) {
		// Matches
		this.entries.forEach((localObj) => {
			oDs.entries.forEach((remoteObj) => {
				if (conditionCb(localObj, remoteObj)) {
					localObj[target] = remoteObj;
				}
			});
		});

		return this;
	}
	copy() {
		return new DataSet(clone(this.entries));
	}

	/* Filter operations */
	reduce(conditionCb) {
		this.entries = this.filter(conditionCb);
		return this;
	}
	toArray(conditionCb) {
		return conditionCb ? this.entries.filter(conditionCb) : this.entries;
	}
	first(conditionCb) {
		const result = this.filter(conditionCb);
		return ( result.length >= 1 ) ? result[0] : undefined;
	}

	/* Aggregation operations */
	groupBy(groupByFieldsInput, outputFieldName) {
       
		// Ensure that group groupByFieldsInput is an array
		let groupByFields = Array.isArray(groupByFieldsInput) ? groupByFieldsInput : [groupByFieldsInput],
			outputMap = {},
			output = [];

		this.entries.forEach((localObj) => {
			let currentOutputObj = outputMap;

			groupByFields.forEach(f => {
				let fieldValue = localObj[f] !== undefined ? localObj[f] : "undefined";
				if (currentOutputObj[fieldValue] === undefined) {
					currentOutputObj[fieldValue] = { field: f, value: fieldValue, children: {} };
				}
				currentOutputObj = currentOutputObj[fieldValue].children;
			});
           
			if (Array.isArray(currentOutputObj[outputFieldName])) {
				currentOutputObj[outputFieldName].push(localObj);
			} else {
				currentOutputObj[outputFieldName] = [localObj];
			}

		});

		const rebuildResults = (currentLevel, trail) => {
			trail = Object.assign({}, trail) || {};
			Object.values(currentLevel).forEach((currentItem) => {
				if (Array.isArray(currentItem)) {
					trail[outputFieldName] = currentItem;
					output.push(trail);
				} else {
					trail[currentItem.field] = currentItem.value;
					rebuildResults(currentItem.children, trail);
				}
			});
		};

		rebuildResults(outputMap);

		return new DataSet(output);

	}    
   
	/* Aggregation operations */
	total(outputFieldName) {
       
		let newEntry = {};
		newEntry[outputFieldName] = this.entries;

		return new DataSet([newEntry]);

	}

	avg(field, outputFieldName, mapCb) {
		this.entries.forEach(e => {
			const data = e[field].map(mapCb);
			e[outputFieldName] = data.reduce((a,b) => a + b, 0) / data.length;
		});
		return this;
	}

	sum(field, outputFieldName, mapCb) {
		this.entries.forEach(e => {
			e[outputFieldName] = e[field].map(mapCb).reduce((a,b) => a + b, 0);
		});
		return this;
	}

	min(field, outputFieldName, mapCb) {
		this.entries.forEach(e => {
			e[outputFieldName] = Math.min(...e[field].map(mapCb));
		});
		return this;
	}

	max(field, outputFieldName, mapCb) {
		this.entries.forEach(e => {
			e[outputFieldName] = Math.max(...e[field].map(mapCb));
		});
		return this;
	}


	countd(field, outputFieldName, mapCb) {
		this.entries.forEach(e => {
			const data = e[field].map(mapCb);
			e[outputFieldName] = new Set(data).size;
		});
		return this;
	}

	count(field, outputFieldName, mapCb) {
		this.entries.forEach(e => {
			e[outputFieldName] = e[field].map(mapCb).length;
		});
		return this;
	}

	calc(outputFieldName, calcCb) {
		this.entries.forEach(e => {
			e[outputFieldName] = calcCb(e);
		});
		return this;
	}

	autonumber(outputFieldName) {
		let current = 0;
		this.entries.forEach(e => {
			e[outputFieldName] = current++;
		});
		return this;
	}

}

export default DataSet;
export { DataSet, clone, validate };