import escape from 'lodash-es/escape';
import isDate from 'lodash-es/isDate';

import { currentSiteId } from 'scrivito_sdk/app_support/current_page';
import { getDetailsPageAndQuery } from 'scrivito_sdk/app_support/get_details_page_url';
import { hasComponent } from 'scrivito_sdk/app_support/has_component';
import {
  InternalError,
  assumeString,
  convertToFloat,
  convertToInteger,
  isPresent,
  logError,
} from 'scrivito_sdk/common';
import {
  DataItem,
  DataScope,
  DataStack,
  applyDataLocator,
} from 'scrivito_sdk/data_integration';
import {
  BasicLink,
  BasicObj,
  BasicTypeInfo,
  BasicWidget,
  CmsAttributeType,
  getContentValueOrConnection,
  isContentConnection,
} from 'scrivito_sdk/models';
import { useDataStackOrThrow } from 'scrivito_sdk/react/data_context_container';
import {
  AttributeDefinitions,
  AttributeValueOf,
  Obj,
  Schema,
  Widget,
  unwrapAppClass,
  wrapInAppClass,
} from 'scrivito_sdk/realm';

/** @public */
export function useContent<A extends keyof AttributeDefinitions & string>(
  content: Obj | Widget,
  attributeName: string
): AttributeValueOf<AttributeDefinitions, A> {
  return resolveContent(content, attributeName, useDataStackOrThrow());
}

// Exported for test purpose only
export function resolveContent(
  content: Obj | Widget,
  attributeName: string,
  dataStack: DataStack
): ReturnType<typeof useContent> {
  const typeInfo = getTypeInfo(content, attributeName);
  if (!typeInfo) return null;

  return wrapInAppClass(
    resolveBasicContent(
      unwrapAppClass(content),
      attributeName,
      typeInfo,
      dataStack
    )
  );
}

function resolveBasicContent<T extends CmsAttributeType>(
  basicContent: BasicObj | BasicWidget,
  attributeName: string,
  typeInfo: BasicTypeInfo<T>,
  dataStack: DataStack
) {
  const valueOrConnection = getContentValueOrConnection(
    basicContent,
    attributeName,
    typeInfo
  );

  if (isContentConnection(valueOrConnection)) {
    return toBasicValue(
      applyDataLocator(dataStack, valueOrConnection[1]),
      typeInfo
    );
  }

  return valueOrConnection[1];
}

function toBasicValue<T extends CmsAttributeType>(
  dataScope: DataScope,
  typeInfo: BasicTypeInfo<T>
) {
  const itemAttribute = dataScope.dataItemAttribute();
  if (itemAttribute) {
    return itemAttributeToBasicValue(
      itemAttribute.dataItem(),
      itemAttribute.attributeName(),
      typeInfo
    );
  }

  const dataItem = dataScope.dataItem();
  if (dataItem) return itemToBasicValue(dataItem, typeInfo[0]);

  return scopeToBasicValue(dataScope, typeInfo);
}

function scopeToBasicValue<T extends CmsAttributeType>(
  dataScope: DataScope,
  [attributeType]: BasicTypeInfo<T>
) {
  const items = dataScope.take();

  if (attributeType === 'linklist') {
    return items.map(itemToLink).filter(isPresent);
  }

  if (attributeType === 'referencelist') {
    return items.map(itemToReference).filter(isPresent);
  }

  return toDefaultValue(attributeType);
}

function itemAttributeToBasicValue<T extends CmsAttributeType>(
  dataItem: DataItem,
  attributeName: string,
  typeInfo: BasicTypeInfo<T>
) {
  const obj = dataItem.obj();

  if (obj) {
    return objAttributeToBasicValue(obj, attributeName, typeInfo);
  }

  return externalAttributeToBasicValue(dataItem, attributeName, typeInfo);
}

function itemToBasicValue<T extends CmsAttributeType>(
  dataItem: DataItem,
  attributeType: T
) {
  switch (attributeType) {
    case 'reference':
      return itemToReference(dataItem);
    case 'referencelist':
      return toList(itemToReference(dataItem));
    case 'link':
      return itemToLink(dataItem);
    case 'linklist':
      return toList(itemToLink(dataItem));
    default:
      return null;
  }
}

function itemToReference(dataItem: DataItem) {
  return unwrapAppClass(dataItem.obj()) || null;
}

function itemToLink(dataItem: DataItem) {
  const obj = dataItem.obj();
  let link: BasicLink | null = null;

  if (obj && (hasComponent(obj.objClass()) || obj.isBinary())) {
    link = new BasicLink({ objId: obj.id() });
  }

  const detailsPageAndQuery = getDetailsPageAndQuery(dataItem, currentSiteId());

  if (detailsPageAndQuery) {
    const { detailsPage, queryString } = detailsPageAndQuery;
    link = new BasicLink({ objId: detailsPage.id(), query: queryString });
  }

  return link;
}

function toList<T>(value: T | null): [T] | [] {
  return value === null ? [] : [value];
}

function objAttributeToBasicValue<T extends CmsAttributeType>(
  obj: Obj,
  attributeName: string,
  typeInfo: BasicTypeInfo<T>
) {
  const basicObj = unwrapAppClass(obj);

  if (getTypeInfo(obj, attributeName)?.[0] === 'datalocator') {
    logError('Connecting a "datalocator" attribute is not possible');
    return null;
  }

  return basicObj.get(attributeName, typeInfo);
}

function externalAttributeToBasicValue<T extends CmsAttributeType>(
  dataItem: DataItem,
  attributeName: string,
  typeInfo: BasicTypeInfo<T>
) {
  const externalAttributeType = dataItem.dataClass().attributeDefinitions()[
    attributeName
  ]?.[0];

  const unknownValue = dataItem.get(attributeName);

  if (externalAttributeType === 'string') {
    return externalStringAttributeToBasicValue(unknownValue, typeInfo);
  }

  if (externalAttributeType === 'enum') {
    return externalEnumAttributeToBasicValue(unknownValue, typeInfo);
  }

  if (externalAttributeType === 'number') {
    return externalNumberAttributeToBasicValue(unknownValue, typeInfo);
  }

  if (externalAttributeType === 'boolean') {
    return externalBooleanAttributeToBasicValue(unknownValue, typeInfo);
  }

  if (externalAttributeType === 'date') {
    return externalDateAttributeToBasicValue(unknownValue, typeInfo);
  }

  if (externalAttributeType === 'reference') {
    return externalReferenceAttributeToBasicValue(unknownValue, typeInfo);
  }

  return null;
}

function externalStringAttributeToBasicValue<T extends CmsAttributeType>(
  unknownValue: unknown,
  typeInfo: BasicTypeInfo<T>
) {
  const value = assumeString(unknownValue);
  const [targetAttributeType, targetTypeInfoConfig] = typeInfo;

  switch (targetAttributeType) {
    case 'string':
      return value;
    case 'html':
      return escape(value);
    case 'enum':
      return externalStringAttributeToEnumValue(value, targetTypeInfoConfig);
    case 'multienum':
      return toList(
        externalStringAttributeToEnumValue(value, targetTypeInfoConfig)
      );
    case 'stringlist':
      return toList(value);
    default:
      return null;
  }
}

function externalEnumAttributeToBasicValue<T extends CmsAttributeType>(
  unknownValue: unknown,
  typeInfo: BasicTypeInfo<T>
) {
  const value = assumeStringOrNull(unknownValue);
  const [targetAttributeType] = typeInfo;

  if (value === null) {
    switch (targetAttributeType) {
      case 'string':
        return '';
      case 'multienum':
        return [];
      default:
        return null;
    }
  }

  return externalStringAttributeToBasicValue(unknownValue, typeInfo);
}

function externalNumberAttributeToBasicValue<T extends CmsAttributeType>(
  unknownValue: unknown,
  typeInfo: BasicTypeInfo<T>
) {
  const value = assumeNumber(unknownValue);
  const [targetAttributeType] = typeInfo;

  switch (targetAttributeType) {
    case 'float':
      return convertToFloat(value);
    case 'integer':
      return convertToInteger(value);
    default:
      return null;
  }
}

function externalBooleanAttributeToBasicValue<T extends CmsAttributeType>(
  unknownValue: unknown,
  typeInfo: BasicTypeInfo<T>
) {
  const value = assumeBoolean(unknownValue);
  const [targetAttributeType] = typeInfo;

  return targetAttributeType === 'boolean' ? value : toDefaultValue('boolean');
}

function externalDateAttributeToBasicValue<T extends CmsAttributeType>(
  unknownValue: unknown,
  typeInfo: BasicTypeInfo<T>
) {
  const value = assumeDateOrNull(unknownValue);
  const [targetAttributeType] = typeInfo;

  return targetAttributeType === 'date' || targetAttributeType === 'datetime'
    ? value
    : null;
}

function externalReferenceAttributeToBasicValue<T extends CmsAttributeType>(
  unknownValue: unknown,
  typeInfo: BasicTypeInfo<T>
) {
  if (unknownValue instanceof DataItem) {
    switch (typeInfo[0]) {
      case 'link':
        return itemToLink(unknownValue);
      case 'linklist':
        return toList(itemToLink(unknownValue));
      default:
        null;
    }
  }

  return null;
}

function externalStringAttributeToEnumValue(
  value: string,
  typeInfoConfig: BasicTypeInfo<'enum'>[1]
) {
  return typeInfoConfig.values.includes(value) ? value : null;
}

function toDefaultValue<T extends CmsAttributeType>(attributeType: T) {
  switch (attributeType) {
    case 'linklist':
    case 'referencelist':
      return [];
    case 'boolean':
      return false;
    default:
      return null;
  }
}

function getTypeInfo(content: Obj | Widget, attributeName: string) {
  return Schema.forInstance(content)?.attributes()[attributeName];
}

function assumeStringOrNull(value: unknown): string | null {
  if (value === null || typeof value === 'string') return value;
  throw new InternalError();
}

function assumeBoolean(value: unknown) {
  if (typeof value === 'boolean') return value;
  throw new InternalError();
}

function assumeNumber(value: unknown) {
  if (typeof value === 'number') return value;
  throw new InternalError();
}

function assumeDateOrNull(value: unknown): Date | null {
  if (value === null || isDate(value)) return value;
  throw new InternalError();
}