import { ErrorObject } from 'ajv';
import get from 'lodash/get';
import {
  createErrorHandler,
  CustomValidator,
  ErrorTransformer,
  FormContextType,
  getDefaultFormState,
  getUiOptions,
  PROPERTIES_KEY,
  RJSFSchema,
  RJSFValidationError,
  StrictRJSFSchema,
  toErrorSchema,
  UiSchema,
  unwrapErrorHandler,
  validationDataMerge,
  ValidatorType,
} from '@rjsf/utils';

export type RawValidationErrorsType<Result = any> = { errors?: Result[]; validationError?: Error };

/** Transforming the error output from ajv to format used by @rjsf/utils.
 * At some point, components should be updated to support ajv.
 *
 * @param errors - The list of AJV errors to convert to `RJSFValidationErrors`
 * @param [uiSchema] - An optional uiSchema that is passed to `transformErrors` and `customValidate`
 */
export function transformRJSFValidationErrors<
  T = any,
  S extends StrictRJSFSchema = RJSFSchema,
  F extends FormContextType = any
>(errors: ErrorObject[] = [], uiSchema?: UiSchema<T, S, F>): RJSFValidationError[] {
  return errors.map((e: ErrorObject) => {
    const { instancePath, keyword, params, schemaPath, parentSchema, ...rest } = e;
    let { message = '' } = rest;
    let property = instancePath.replace(/\//g, '.');
    let stack = `${property} ${message}`.trim();

    if ('missingProperty' in params) {
      property = property ? `${property}.${params.missingProperty}` : params.missingProperty;
      const currentProperty: string = params.missingProperty;
      let uiSchemaTitle = getUiOptions(get(uiSchema, `${property.replace(/^\./, '')}`)).title;
      if (uiSchemaTitle === undefined) {
        const uiSchemaPath = schemaPath
          .replace(/\/properties\//g, '/')
          .split('/')
          .slice(1, -1)
          .concat([currentProperty]);
        uiSchemaTitle = getUiOptions(get(uiSchema, uiSchemaPath)).title;
      }

      if (uiSchemaTitle) {
        message = message.replace(`'${currentProperty}'`, `'${uiSchemaTitle}'`);
      } else {
        const parentSchemaTitle = get(parentSchema, [PROPERTIES_KEY, currentProperty, 'title']);

        if (parentSchemaTitle) {
          message = message.replace(`'${currentProperty}'`, `'${parentSchemaTitle}'`);
        }
      }

      stack = message;
    } else {
      const uiSchemaTitle = getUiOptions<T, S, F>(get(uiSchema, `${property.replace(/^\./, '')}`)).title;

      if (uiSchemaTitle) {
        stack = `'${uiSchemaTitle}' ${message}`.trim();
      } else {
        const parentSchemaTitle = parentSchema?.title;

        if (parentSchemaTitle) {
          stack = `'${parentSchemaTitle}' ${message}`.trim();
        }
      }
    }

    // put data in expected format
    return {
      name: keyword,
      property,
      message,
      params, // specific to ajv
      stack,
      schemaPath,
    };
  });
}

/** This function processes the `formData` with an optional user contributed `customValidate` function, which receives
 * the form data and a `errorHandler` function that will be used to add custom validation errors for each field. Also
 * supports a `transformErrors` function that will take the raw AJV validation errors, prior to custom validation and
 * transform them in what ever way it chooses.
 *
 * @param validator - The `ValidatorType` implementation used for the `getDefaultFormState()` call
 * @param rawErrors - The list of raw `ErrorObject`s to process
 * @param formData - The form data to validate
 * @param schema - The schema against which to validate the form data
 * @param [customValidate] - An optional function that is used to perform custom validation
 * @param [transformErrors] - An optional function that is used to transform errors after AJV validation
 * @param [uiSchema] - An optional uiSchema that is passed to `transformErrors` and `customValidate`
 */
export default function processRawValidationErrors<
  T = any,
  S extends StrictRJSFSchema = RJSFSchema,
  F extends FormContextType = any
>(
  validator: ValidatorType<T, S, F>,
  rawErrors: RawValidationErrorsType<ErrorObject>,
  formData: T | undefined,
  schema: S,
  customValidate?: CustomValidator<T, S, F>,
  transformErrors?: ErrorTransformer<T, S, F>,
  uiSchema?: UiSchema<T, S, F>
) {
  const { validationError: invalidSchemaError } = rawErrors;
  let errors = transformRJSFValidationErrors<T, S, F>(rawErrors.errors, uiSchema);

  if (invalidSchemaError) {
    errors = [...errors, { stack: invalidSchemaError!.message }];
  }
  if (typeof transformErrors === 'function') {
    errors = transformErrors(errors, uiSchema);
  }

  let errorSchema = toErrorSchema<T>(errors);

  if (invalidSchemaError) {
    errorSchema = {
      ...errorSchema,
      $schema: {
        __errors: [invalidSchemaError!.message],
      },
    };
  }

  if (typeof customValidate !== 'function') {
    return { errors, errorSchema };
  }

  // Include form data with undefined values, which is required for custom validation.
  const newFormData = getDefaultFormState<T, S, F>(validator, schema, formData, schema, true) as T;

  const errorHandler = customValidate(newFormData, createErrorHandler<T>(newFormData), uiSchema);
  const userErrorSchema = unwrapErrorHandler<T>(errorHandler);
  return validationDataMerge<T>({ errors, errorSchema }, userErrorSchema);
}