import set from 'lodash/set'
import createFormField, { isFormField } from './createFormField'
import {
  flattenFields,
  getErrorStrs,
  startsWith,
} from './utils'

function partOf (a, b) {
  return b.indexOf(a) === 0 && ['.', '['].indexOf(b[a.length]) !== -1
}

class FieldsStore {
  constructor (fields) {
    this.fields = this.flattenFields(fields)
    this.fieldsMeta = {}
  }

  updateFields (fields) {
    this.fields = this.flattenFields(fields)
  }

  flattenFields (fields) {
    return flattenFields(
      fields,
      (_, node) => isFormField(node),
      'You must wrap field data with `createFormField`.'
    )
  }

  flattenRegisteredFields (fields) {
    const validFieldsName = this.getAllFieldsName()
    return flattenFields(
      fields,
      path => validFieldsName.indexOf(path) >= 0,
      'You cannot set field before registering it.'
    )
  }

  setFieldsInitialValue = (initialValues) => {
    const flattenedInitialValues = this.flattenRegisteredFields(initialValues)
    const fieldsMeta = this.fieldsMeta
    Object.keys(flattenedInitialValues).forEach(name => {
      if (fieldsMeta[name]) {
        this.setFieldMeta(name, {
          ...this.getFieldMeta(name),
          initialValue: flattenedInitialValues[name],
        })
      }
    })
  }

  setFields (fields) {
    const fieldsMeta = this.fieldsMeta
    const nowFields = {
      ...this.fields,
      ...fields,
    }
    const nowValues = {}
    Object.keys(fieldsMeta)
      .forEach((f) => { nowValues[f] = this.getValueFromFields(f, nowFields) })
    Object.keys(nowValues).forEach((f) => {
      const value = nowValues[f]
      const fieldMeta = this.getFieldMeta(f)
      if (fieldMeta && fieldMeta.normalize) {
        const nowValue =
                fieldMeta.normalize(value, this.getValueFromFields(f, this.fields), nowValues)
        if (nowValue !== value) {
          nowFields[f] = {
            ...nowFields[f],
            value: nowValue,
          }
        }
      }
    })
    this.fields = nowFields
  }

  resetFields (ns) {
    const { fields } = this
    const names = ns
      ? this.getValidFieldsFullName(ns)
      : this.getAllFieldsName()
    return names.reduce((acc, name) => {
      const field = fields[name]
      if (field && 'value' in field) {
        acc[name] = {}
      }
      return acc
    }, {})
  }

  setFieldMeta (name, meta) {
    this.fieldsMeta[name] = meta
  }

  getFieldMeta (name) {
    this.fieldsMeta[name] = this.fieldsMeta[name] || {}
    return this.fieldsMeta[name]
  }

  getValueFromFields (name, fields) {
    const field = fields[name]
    if (field && 'value' in field) {
      return field.value
    }
    const fieldMeta = this.getFieldMeta(name)
    return fieldMeta && fieldMeta.initialValue
  }

  getAllValues = () => {
    const { fieldsMeta, fields } = this
    return Object.keys(fieldsMeta)
      .reduce((acc, name) => set(acc, name, this.getValueFromFields(name, fields)), {})
  }

  getValidFieldsName () {
    const { fieldsMeta } = this
    return fieldsMeta
      ? Object.keys(fieldsMeta).filter(name => !this.getFieldMeta(name).hidden)
      : []
  }

  getAllFieldsName () {
    const { fieldsMeta } = this
    return fieldsMeta ? Object.keys(fieldsMeta) : []
  }

  getValidFieldsFullName (maybePartialName) {
    const maybePartialNames = Array.isArray(maybePartialName)
      ? maybePartialName : [maybePartialName]
    return this.getValidFieldsName()
      .filter(fullName => maybePartialNames.some(partialName => (
        fullName === partialName || (
          startsWith(fullName, partialName) &&
          ['.', '['].indexOf(fullName[partialName.length]) >= 0
        )
      )))
  }

  getFieldValuePropValue (fieldMeta) {
    const { name, getValueProps, valuePropName } = fieldMeta
    const field = this.getField(name)
    const fieldValue = 'value' in field
      ? field.value : fieldMeta.initialValue
    if (getValueProps) {
      return getValueProps(fieldValue)
    }
    return { [valuePropName]: fieldValue }
  }

  getField (name) {
    return {
      ...this.fields[name],
      name,
    }
  }

  getNotCollectedFields () {
    return this.getValidFieldsName()
      .filter(name => !this.fields[name])
      .map(name => ({
        name,
        dirty: false,
        value: this.getFieldMeta(name).initialValue,
      }))
      .reduce((acc, field) => set(acc, field.name, createFormField(field)), {})
  }

  getNestedAllFields () {
    return Object.keys(this.fields)
      .reduce(
        (acc, name) => set(acc, name, createFormField(this.fields[name])),
        this.getNotCollectedFields()
      )
  }

  getFieldMember (name, member) {
    return this.getField(name)[member]
  }

  getNestedFields (names, getter) {
    const fields = names || this.getValidFieldsName()
    return fields.reduce((acc, f) => set(acc, f, getter(f)), {})
  }

  getNestedField (name, getter) {
    const fullNames = this.getValidFieldsFullName(name)
    if (
      fullNames.length === 0 || // Not registered
        (fullNames.length === 1 && fullNames[0] === name) // Name already is full name.
    ) {
      return getter(name)
    }
    const isArrayValue = fullNames[0][name.length] === '['
    const suffixNameStartIndex = isArrayValue ? name.length : name.length + 1
    return fullNames
      .reduce(
        (acc, fullName) => set(
          acc,
          fullName.slice(suffixNameStartIndex),
          getter(fullName)
        ),
        isArrayValue ? [] : {}
      )
  }

  getFieldsValue = (names) => {
    return this.getNestedFields(names, this.getFieldValue)
  }

  getFieldValue = (name) => {
    const { fields } = this
    return this.getNestedField(name, (fullName) => this.getValueFromFields(fullName, fields))
  }

  getFieldsError = (names) => {
    return this.getNestedFields(names, this.getFieldError)
  }

  getFieldError = (name) => {
    return this.getNestedField(
      name,
      (fullName) => getErrorStrs(this.getFieldMember(fullName, 'errors'))
    )
  }

  isFieldValidating = (name) => {
    return this.getFieldMember(name, 'validating')
  }

  isFieldsValidating = (ns) => {
    const names = ns || this.getValidFieldsName()
    return names.some((n) => this.isFieldValidating(n))
  }

  isFieldTouched = (name) => {
    return this.getFieldMember(name, 'touched')
  }

  isFieldsTouched = (ns) => {
    const names = ns || this.getValidFieldsName()
    return names.some((n) => this.isFieldTouched(n))
  }

  // @private
  // BG: `a` and `a.b` cannot be use in the same form
  isValidNestedFieldName (name) {
    const names = this.getAllFieldsName()
    return names.every(n => !partOf(n, name) && !partOf(name, n))
  }

  clearField (name) {
    delete this.fields[name]
    delete this.fieldsMeta[name]
  }
}

export default function createFieldsStore (fields) {
  return new FieldsStore(fields)
}