import { create } from 'zustand'

import type {
  DefaultValues,
  FormFieldArray,
  FormFieldNames,
  FormValueControl,
  FormValues,
  FormValuesState,
} from './types.js'

export const formDefaultValues: DefaultValues = {
  fromAmount: '',
  toAmount: '',
  tokenSearchFilter: '',
}

const defaultValueToFormValue = <T>(value: T): FormValueControl<T> => ({
  isTouched: false,
  isDirty: false,
  value,
})

const valuesToFormValues = (defaultValues: DefaultValues): FormValues => {
  return (Object.keys(defaultValues) as FormFieldNames[]).reduce(
    (accum, key) => {
      accum[key] = defaultValueToFormValue(defaultValues[key]) as never
      return accum
    },
    {} as FormValues
  )
}

const isString = (str: any) => typeof str === 'string' || str instanceof String

const getUpdatedTouchedFields = (userValues: FormValues) => {
  return (Object.keys(userValues) as FormFieldNames[]).reduce(
    (accum, key) => {
      if (userValues[key]?.isTouched) {
        accum[key] = true
      }
      return accum
    },
    {} as Record<FormFieldNames, boolean>
  )
}

const mergeDefaultFormValues = (
  userValues: FormValues,
  defaultValues: FormValues
) =>
  (Object.keys(defaultValues) as FormFieldNames[]).reduce<FormValues>(
    (accum, key) => {
      const formValue = {
        isTouched: !!(
          userValues[key]?.isTouched || defaultValues[key]?.isTouched
        ),
        isDirty: !!(userValues[key]?.isDirty || defaultValues[key]?.isTouched),
        value:
          userValues[key]?.value || Number.isFinite(userValues[key]?.value)
            ? userValues[key]?.value
            : defaultValues[key]?.value,
      }
      accum[key] = formValue as never
      return accum
    },
    { ...valuesToFormValues(formDefaultValues) }
  )

export const createFormStore = (defaultValues?: DefaultValues) =>
  create<FormValuesState>((set, get) => {
    const _defaultValues = valuesToFormValues({
      ...formDefaultValues,
      ...defaultValues,
    })
    return {
      defaultValues: _defaultValues,
      userValues: _defaultValues,
      touchedFields: {},
      isValid: true,
      isValidating: false,
      errors: {},
      validation: {},
      setDefaultValues: (defaultValue) => {
        const defaultFormValues = valuesToFormValues(defaultValue)
        set((state) => ({
          defaultValues: defaultFormValues,
          userValues: mergeDefaultFormValues(
            state.userValues,
            defaultFormValues
          ),
        }))
      },
      setUserAndDefaultValues: (formValues) => {
        const currentUserValues = get().userValues
        ;(Object.keys(formValues) as FormFieldNames[]).forEach((key) => {
          if (formValues[key] !== currentUserValues[key]?.value) {
            get().resetField(key, { defaultValue: formValues[key] })
            get().setFieldValue(key, formValues[key], { isTouched: true })
          }
        })
      },
      isTouched: (fieldName: FormFieldNames) =>
        !!get().userValues[fieldName]?.isTouched,
      isDirty: (fieldName: FormFieldNames) =>
        !!get().userValues[fieldName]?.isDirty,
      setAsTouched: (fieldName: FormFieldNames) => {
        const userValues = {
          ...get().userValues,
          [fieldName]: {
            ...get().userValues[fieldName],
            isTouched: true,
          },
        }

        const touchedFields = getUpdatedTouchedFields(userValues)

        set(() => ({
          userValues,
          touchedFields,
        }))
      },
      resetField: (fieldName, { defaultValue } = {}) => {
        if (defaultValue) {
          const fieldValues = {
            ...get().defaultValues[fieldName],
            value: defaultValue,
          }
          const defaultValues = {
            ...get().defaultValues,
            [fieldName]: { ...fieldValues },
          }
          const userValues = {
            ...get().userValues,
            [fieldName]: { ...fieldValues },
          }
          const touchedFields = getUpdatedTouchedFields(userValues)

          set(() => {
            return {
              defaultValues,
              userValues,
              touchedFields,
            }
          })
        } else {
          const userValues = {
            ...get().userValues,
            [fieldName]: { ...get().defaultValues[fieldName] },
          }
          const touchedFields = getUpdatedTouchedFields(userValues)

          set(() => ({
            userValues,
            touchedFields,
          }))
        }
      },
      setFieldValue: (fieldName, value, { isDirty, isTouched } = {}) => {
        const userValues = {
          ...get().userValues,
          [fieldName]: {
            value,
            isDirty:
              isDirty === undefined
                ? get().userValues[fieldName]?.isDirty
                : isDirty,
            isTouched:
              isTouched === undefined
                ? get().userValues[fieldName]?.isTouched
                : isTouched,
          },
        }

        const touchedFields = getUpdatedTouchedFields(userValues)

        set(() => ({
          userValues,
          touchedFields,
        }))
      },
      getFieldValues: <T extends FormFieldNames[]>(...names: T) =>
        names.map((name) => get().userValues[name]?.value) as FormFieldArray<T>,
      addFieldValidation: (name, validationFn) => {
        set((state) => ({
          validation: {
            ...state.validation,
            [name]: validationFn,
          },
        }))
      },
      triggerFieldValidation: async (name) => {
        try {
          let valid = true
          set(() => ({ isValid: false, isValidating: true }))

          const validationFn = get().validation[name]

          if (validationFn) {
            const result = await validationFn(get().userValues?.[name]?.value)
            if (isString(result)) {
              valid = false
              set((state) => ({
                errors: {
                  ...state.errors,
                  [name]: result,
                },
              }))
            } else {
              valid = result as boolean
              if (valid) {
                get().clearErrors(name)
              }
            }
          }

          set(() => ({ isValid: valid, isValidating: false }))
          return valid
        } catch (err) {
          set(() => ({ isValidating: false }))
          throw err
        }
      },
      clearErrors: (name) => {
        const newErrors = { ...get().errors }

        delete newErrors[name]

        set(() => ({
          errors: newErrors,
        }))
      },
    }
  })