import { useEffect, useMemo, useRef, useState } from 'react';
import {
  DecodedValueMap,
  QueryParamConfig,
  QueryParamConfigMap,
  StringParam,
} from 'serialize-query-params';
import { decodedParamCache } from './decodedParamCache';
import {
  extendParamConfigForKeys,
  convertInheritedParamStringsToParams,
} from './inheritedParams';
import { makeStableGetLatestDecodedValues } from './latestValues';
import { memoSearchStringToObject } from './memoSearchStringToObject';
import { mergeOptions, QueryParamOptions } from './options';
import { useQueryParamContext } from './QueryParamProvider';
import {
  QueryParamConfigMapWithInherit,
  SetQuery,
  UrlUpdateType,
} from './types';
import { enqueueUpdate } from './updateSearchString';
import { serializeUrlNameMap } from './urlName';

// for multiple param config
type ChangesType<DecodedValueMapType> =
  | Partial<DecodedValueMapType>
  | ((latestValues: DecodedValueMapType) => Partial<DecodedValueMapType>);

type UseQueryParamsResult<QPCMap extends QueryParamConfigMap> = [
  DecodedValueMap<QPCMap>,
  SetQuery<QPCMap>
];
type ExpandInherits<QPCMap extends QueryParamConfigMapWithInherit> = {
  [ParamName in keyof QPCMap]: QPCMap[ParamName] extends string
    ? typeof StringParam
    : QPCMap[ParamName] extends QueryParamConfig<any>
    ? QPCMap[ParamName]
    : never;
};

/**
 * Given a query parameter configuration (mapping query param name to { encode, decode }),
 * return an object with the decoded values and a setter for updating them.
 */
export function useQueryParams<
  QPCMap extends QueryParamConfigMap = QueryParamConfigMap
>(): UseQueryParamsResult<QPCMap>;
export function useQueryParams<QPCMap extends QueryParamConfigMapWithInherit>(
  names: string[],
  options?: QueryParamOptions
): UseQueryParamsResult<ExpandInherits<QPCMap>>;
export function useQueryParams<
  QPCMap extends QueryParamConfigMapWithInherit,
  OutputQPCMap extends QueryParamConfigMap = ExpandInherits<QPCMap>
>(
  paramConfigMap: QPCMap,
  options?: QueryParamOptions
): UseQueryParamsResult<OutputQPCMap>;
export function useQueryParams(
  arg1?: string[] | QueryParamConfigMapWithInherit,
  arg2?: QueryParamConfig<any> | QueryParamOptions
): UseQueryParamsResult<any> {
  const { adapter, options: contextOptions } = useQueryParamContext();
  const [stableGetLatest] = useState(makeStableGetLatestDecodedValues);

  // intepret the overloaded arguments
  const { paramConfigMap: paramConfigMapWithInherit, options } = parseArguments(
    arg1,
    arg2
  );

  const mergedOptions = useMemo(() => {
    return mergeOptions(contextOptions, options);
  }, [contextOptions, options]);

  // interpret params that were configured up the chain
  let paramConfigMap = convertInheritedParamStringsToParams(
    paramConfigMapWithInherit,
    mergedOptions
  );

  // what is the current stringified value?
  const parsedParams = memoSearchStringToObject(
    mergedOptions.searchStringToObject,
    adapter.location.search,
    serializeUrlNameMap(paramConfigMap) // note we serialize for memo purposes
  );

  // do we want to include all params from the URL even if not configured?
  if (mergedOptions.includeAllParams) {
    paramConfigMap = extendParamConfigForKeys(
      paramConfigMap,
      Object.keys(parsedParams),
      mergedOptions.params,
      StringParam
    );
  }

  // run decode on each key
  const decodedValues = stableGetLatest(
    parsedParams,
    paramConfigMap,
    decodedParamCache
  );

  // clear out unused values in cache
  // use string for relatively stable effect dependency
  const paramKeyString = Object.keys(paramConfigMap).join('\0');
  useEffect(() => {
    const paramNames = paramKeyString.split('\0');
    decodedParamCache.registerParams(paramNames);
    return () => {
      decodedParamCache.unregisterParams(paramNames);
    };
  }, [paramKeyString]);

  // create a setter for updating multiple query params at once
  // use a ref for callback dependencies so we don't generate a new one unnecessarily
  const callbackDependencies = {
    adapter,
    paramConfigMap,
    options: mergedOptions,
  };
  const callbackDependenciesRef =
    useRef<typeof callbackDependencies>(callbackDependencies);
  if (callbackDependenciesRef.current == null) {
    callbackDependenciesRef.current = callbackDependencies;
  }
  useEffect(() => {
    callbackDependenciesRef.current.adapter = adapter;
    callbackDependenciesRef.current.paramConfigMap = paramConfigMap;
    callbackDependenciesRef.current.options = mergedOptions;
  }, [adapter, paramConfigMap, mergedOptions]);

  // create callback with stable identity
  const [setQuery] = useState(() => {
    const setQuery = (
      changes: ChangesType<DecodedValueMap<any>>,
      updateType?: UrlUpdateType
    ) => {
      // read from a ref so we don't generate new setters each time any change
      const { adapter, paramConfigMap, options } =
        callbackDependenciesRef.current!;
      if (updateType == null) updateType = options.updateType;

      enqueueUpdate(
        {
          changes,
          updateType,
          currentSearchString: adapter.location.search,
          paramConfigMap,
          options,
          adapter,
        },
        { immediate: !options.enableBatching }
      );
    };

    return setQuery;
  });

  return [decodedValues, setQuery];
}

export default useQueryParams;

function parseArguments(
  arg1: string[] | QueryParamConfigMapWithInherit | undefined,
  arg2: QueryParamConfig<any> | QueryParamOptions | undefined
): {
  paramConfigMap: QueryParamConfigMapWithInherit;
  options: QueryParamOptions | undefined;
} {
  let paramConfigMap: QueryParamConfigMapWithInherit;
  let options: QueryParamOptions | undefined;

  if (arg1 === undefined) {
    // useQueryParams()
    paramConfigMap = {};
    options = arg2 as QueryParamOptions | undefined;
  } else if (Array.isArray(arg1)) {
    // useQueryParams(['geo', 'other'])
    // useQueryParams(['geo', 'other'], options)
    paramConfigMap = Object.fromEntries(
      arg1.map((key) => [key, 'inherit' as const])
    );
    options = arg2 as QueryParamOptions | undefined;
  } else {
    // useQueryParams({ geo: NumberParam })
    // useQueryParams({ geo: NumberParam }, options)
    paramConfigMap = arg1;
    options = arg2 as QueryParamOptions | undefined;
  }

  return { paramConfigMap, options };
}