// This should be the new way to implement mecanisms
// In a specific file
// TODO import them automatically
// TODO convert the legacy functions to new files
import barème from 'Engine/mecanisms/barème.js'
import { Parser } from 'nearley'
import {
	add,
	curry,
	divide,
	equals,
	gt,
	gte,
	keys,
	without,
	lt,
	lte,
	map,
	multiply,
	propOr,
	subtract
} from 'ramda'
import React from 'react'
import { evaluateNode, makeJsx, mergeMissing, rewriteNode } from './evaluation'
import Grammar from './grammar.ne'
import {
	mecanismAllOf,
	mecanismComplement,
	mecanismContinuousScale,
	mecanismError,
	mecanismInversion,
	mecanismLinearScale,
	mecanismMax,
	mecanismMin,
	mecanismNumericalSwitch,
	mecanismOneOf,
	mecanismProduct,
	mecanismReduction,
	mecanismSum,
	mecanismSynchronisation,
	mecanismVariations,
	mecanismOnePossibility
} from './mecanisms'
import { Node } from './mecanismViews/common'
import { treat } from './traverse'
import {
	treatNegatedVariable,
	treatVariable,
	treatVariableTransforms
} from './treatVariable'

export let nearley = () => new Parser(Grammar.ParserRules, Grammar.ParserStart)

export let treatString = (rules, rule) => rawNode => {
	/* Strings correspond to infix expressions.
	 * Indeed, a subset of expressions like simple arithmetic operations `3 + (quantity * 2)` or like `salary [month]` are more explicit that their prefixed counterparts.
	 * This function makes them prefixed operations. */

	let [parseResult] = nearley().feed(rawNode).results

	return treatObject(rules, rule)(parseResult)
}

export let treatNumber = rawNode => ({
	text: '' + rawNode,
	category: 'number',
	nodeValue: rawNode,
	type: 'numeric',
	jsx: <span className="number">{rawNode}</span>
})

export let treatOther = rawNode => {
	throw new Error(
		'Cette donnée : ' + rawNode + ' doit être un Number, String ou Object'
	)
}

export let treatObject = (rules, rule, treatOptions) => rawNode => {
	/* TODO instead of describing mecanisms in knownMecanisms.yaml, externalize the mecanisms themselves in an individual file and describe it
	let mecanisms = intersection(keys(rawNode), keys(knownMecanisms))

	if (mecanisms.length != 1) {
	} 
	*/

	let attributes = keys(rawNode),
		descriptiveAttributes = ['description', 'note', 'référence'],
		relevantAttributes = without(descriptiveAttributes, attributes)
	if (relevantAttributes.length !== 1)
		throw new Error(`OUPS : On ne devrait reconnaître que un et un seul mécanisme dans cet objet (au-delà des attributs descriptifs tels que "description", "commentaire", etc.)
			Objet YAML : ${JSON.stringify(rawNode)}
			Cette liste doit avoir un et un seul élément.
			Si vous venez tout juste d'ajouter un nouveau mécanisme, vérifier qu'il est bien intégré dans le dispatch de treat.js
		`)
	let k = relevantAttributes[0],
		v = rawNode[k]

	let knownOperations = {
			'*': [multiply, '∗'],
			'/': [divide, '∕'],
			'+': [add],
			'-': [subtract, '−'],
			'<': [lt],
			'<=': [lte, '≤'],
			'>': [gt],
			'>=': [gte, '≥'],
			'=': [equals],
			'!=': [(a, b) => !equals(a, b), '≠']
		},
		operationDispatch = map(
			([f, symbol]) => mecanismOperation(f, symbol || k),
			knownOperations
		)

	let dispatch = {
			'une de ces conditions': mecanismOneOf,
			'toutes ces conditions': mecanismAllOf,
			'aiguillage numérique': mecanismNumericalSwitch,
			somme: mecanismSum,
			multiplication: mecanismProduct,
			barème,
			'barème linéaire': mecanismLinearScale,
			'barème continu': mecanismContinuousScale,
			'le maximum de': mecanismMax,
			'le minimum de': mecanismMin,
			complément: mecanismComplement,
			'une possibilité': mecanismOnePossibility(rule.dottedName),
			'inversion numérique': mecanismInversion(rule.dottedName),
			allègement: mecanismReduction,
			variations: mecanismVariations,
			synchronisation: mecanismSynchronisation,
			...operationDispatch,
			'≠': () =>
				treatNegatedVariable(treatVariable(rules, rule)(v.explanation)),
			filter: () =>
				treatVariableTransforms(rules, rule)({
					filter: v.filter,
					variable: v.explanation
				}),
			variable: () => treatVariableTransforms(rules, rule)({ variable: v }),
			temporalTransform: () =>
				treatVariableTransforms(rules, rule)({
					variable: v.explanation,
					temporalTransform: v.temporalTransform
				}),
			constant: () => ({
				type: v.type,
				nodeValue: v.nodeValue,
				// eslint-disable-next-line
				jsx: () => <span className={v.type}>{v.rawNode}</span>
			})
		},
		action = propOr(mecanismError, k, dispatch)

	return action(treat(rules, rule, treatOptions), k, v)
}

let mecanismOperation = (operatorFunction, symbol) => (recurse, k, v) => {
	let evaluate = (cache, situation, parsedRules, node) => {
		let explanation = map(
				curry(evaluateNode)(cache, situation, parsedRules),
				node.explanation
			),
			value1 = explanation[0].nodeValue,
			value2 = explanation[1].nodeValue,
			nodeValue =
				value1 == null || value2 == null
					? null
					: operatorFunction(value1, value2),
			missingVariables = mergeMissing(
				explanation[0].missingVariables,
				explanation[1].missingVariables
			)

		return rewriteNode(node, nodeValue, explanation, missingVariables)
	}

	let explanation = v.explanation.map(recurse)

	let jsx = (nodeValue, explanation) => (
		<Node
			classes={'inlineExpression ' + k}
			value={nodeValue}
			child={
				<span className="nodeContent">
					<span className="fa fa" />
					{makeJsx(explanation[0])}
					<span className="operator">{symbol}</span>
					{makeJsx(explanation[1])}
				</span>
			}
		/>
	)

	return {
		evaluate,
		jsx,
		operator: symbol,
		// is this useful ?		text: rawNode,
		explanation
	}
}