import {
  filter, union, constant,
  map, flatten, every, uniqBy,
  some, includes, isEmpty, has
} from 'lodash/fp';
import { compileExpression, compileCode } from '@nx-js/compiler-util';
import {
  $, isSomething, switchCase,
  anyTrue, isNonEmptyArray, executesWithoutException,
  isNonEmptyString, defaultCase,
} from '../common';
import {
  isRecord, isRoot, isaggregateGroup,
  isIndex, getFlattenedHierarchy,
} from './hierarchy';
import { eventsList } from '../common/events';
import { validateAllFields } from './fields';
import {
  applyRuleSet, makerule, stringNotEmpty,
  validationError,
} from '../common/validationCommon';
import { indexRuleSet } from './indexes';
import { validateAllAggregates } from './validateAggregate';

export const ruleSet = (...sets) => constant(flatten([...sets]));

const commonRules = [
  makerule('name', 'node name is not set',
    node => stringNotEmpty(node.name)),
  makerule('type', 'node type not recognised',
    anyTrue(isRecord, isRoot, isIndex, isaggregateGroup)),
];

const recordRules = [
  makerule('fields', 'no fields have been added to the record',
    node => isNonEmptyArray(node.fields)),
  makerule('validationRules', "validation rule is missing a 'messageWhenValid' member",
    node => every(r => has('messageWhenInvalid')(r))(node.validationRules)),
  makerule('validationRules', "validation rule is missing a 'expressionWhenValid' member",
    node => every(r => has('expressionWhenValid')(r))(node.validationRules)),
];


const aggregateGroupRules = [
  makerule('condition', 'condition does not compile',
    a => isEmpty(a.condition)
             || executesWithoutException(
               () => compileExpression(a.condition),
             )),
];

const getRuleSet = node => switchCase(

  [isRecord, ruleSet(
    commonRules,
    recordRules,
  )],

  [isIndex, ruleSet(
    commonRules,
    indexRuleSet,
  )],

  [isaggregateGroup, ruleSet(
    commonRules,
    aggregateGroupRules,
  )],

  [defaultCase, ruleSet(commonRules, [])],
)(node);

export const validateNode = node => applyRuleSet(getRuleSet(node))(node);

export const validateAll = (appHierarchy) => {
  const flattened = getFlattenedHierarchy(
    appHierarchy,
  );

  const duplicateNameRule = makerule(
    'name', 'node names must be unique under shared parent',
    n => filter(f => f.parent() === n.parent()
                          && f.name === n.name)(flattened).length === 1,
  );

  const duplicateNodeKeyErrors = $(flattened, [
    map(n => applyRuleSet([duplicateNameRule])(n)),
    filter(isSomething),
    flatten,
  ]);

  const fieldErrors = $(flattened, [
    filter(isRecord),
    map(validateAllFields),
    flatten,
  ]);

  const aggregateErrors = $(flattened, [
    filter(isaggregateGroup),
    map(s => validateAllAggregates(
      s.aggregates,
    )),
    flatten,
  ]);

  return $(flattened, [
    map(validateNode),
    flatten,
    union(duplicateNodeKeyErrors),
    union(fieldErrors),
    union(aggregateErrors),
  ]);
};

const actionRules = [
  makerule('name', 'action must have a name',
    a => isNonEmptyString(a.name)),
  makerule('behaviourName', 'must supply a behaviour name to the action',
    a => isNonEmptyString(a.behaviourName)),
  makerule('behaviourSource', 'must supply a behaviour source for the action',
    a => isNonEmptyString(a.behaviourSource)),
];

const duplicateActionRule = makerule('', 'action name must be unique', () => {});

const validateAction = action => applyRuleSet(actionRules)(action);


export const validateActions = (allActions) => {
  const duplicateActions = $(allActions, [
    filter(a => filter(a2 => a2.name === a.name)(allActions).length > 1),
    map(a => validationError(duplicateActionRule, a)),
  ]);

  const errors = $(allActions, [
    map(validateAction),
    flatten,
    union(duplicateActions),
    uniqBy('name'),
  ]);

  return errors;
};

const triggerRules = actions => ([
  makerule('actionName', 'must specify an action',
    t => isNonEmptyString(t.actionName)),
  makerule('eventName', 'must specify and event',
    t => isNonEmptyString(t.eventName)),
  makerule('actionName', 'specified action not supplied',
    t => !t.actionName
             || some(a => a.name === t.actionName)(actions)),
  makerule('eventName', 'invalid Event Name',
    t => !t.eventName
             || includes(t.eventName)(eventsList)),
  makerule('optionsCreator', 'Options Creator does not compile - check your expression',
    (t) => {
      if (!t.optionsCreator) return true;
      try {
        compileCode(t.optionsCreator);
        return true;
      } catch (_) { return false; }
    }),
  makerule('condition', 'Trigger condition does not compile - check your expression',
    (t) => {
      if (!t.condition) return true;
      try {
        compileExpression(t.condition);
        return true;
      } catch (_) { return false; }
    }),
]);

export const validateTrigger = (trigger, allActions) => {
  const errors = applyRuleSet(triggerRules(allActions))(trigger);

  return errors;
};

export const validateTriggers = (triggers, allActions) => $(triggers, [
  map(t => validateTrigger(t, allActions)),
  flatten,
]);