/* eslint-disable eqeqeq */
import fakeRestProvider from 'ra-data-fakerest';
import { DataProvider, RaRecord } from 'ra-core';
import pullAt from 'lodash/pullAt';

/**
 * Respond to react-admin data queries using a local database persisted in localStorage
 *
 * Useful for local-first web apps. The storage is shared between tabs.
 *
 * @example // initialize with no data
 *
 * import localStorageDataProvider from 'ra-data-local-storage';
 * const dataProvider = localStorageDataProvider();
 *
 * @example // initialize with default data (will be ignored if data has been modified by user)
 *
 * import localStorageDataProvider from 'ra-data-local-storage';
 * const dataProvider = localStorageDataProvider({
 *   defaultData: {
 *     posts: [
 *       { id: 0, title: 'Hello, world!' },
 *       { id: 1, title: 'FooBar' },
 *     ],
 *     comments: [
 *       { id: 0, post_id: 0, author: 'John Doe', body: 'Sensational!' },
 *       { id: 1, post_id: 0, author: 'Jane Doe', body: 'I agree' },
 *     ],
 *   }
 * });
 */
export default (params?: LocalStorageDataProviderParams): DataProvider => {
    const {
        defaultData = {},
        localStorageKey = 'ra-data-local-storage',
        loggingEnabled = false,
        localStorageUpdateDelay = 10, // milliseconds
    } = params || {};
    const localStorageData = localStorage.getItem(localStorageKey);
    let data = localStorageData ? JSON.parse(localStorageData) : defaultData;

    // change data by executing callback, then persist in localStorage
    const updateLocalStorage = callback => {
        // modify localStorage after the next tick
        setTimeout(() => {
            callback();
            localStorage.setItem(localStorageKey, JSON.stringify(data));
        }, localStorageUpdateDelay);
    };

    let baseDataProvider = fakeRestProvider(
        data,
        loggingEnabled
    ) as DataProvider;

    window?.addEventListener('storage', event => {
        if (event.key === localStorageKey) {
            const newData = event.newValue ? JSON.parse(event.newValue) : {};
            data = newData;
            baseDataProvider = fakeRestProvider(
                newData,
                loggingEnabled
            ) as DataProvider;
        }
    });

    return {
        // read methods are just proxies to FakeRest
        getList: <RecordType extends RaRecord = any>(resource, params) =>
            baseDataProvider
                .getList<RecordType>(resource, params)
                .catch(error => {
                    if (error.code === 1) {
                        // undefined collection error: hide the error and return an empty list instead
                        return { data: [], total: 0 };
                    } else {
                        throw error;
                    }
                }),
        getOne: <RecordType extends RaRecord = any>(resource, params) =>
            baseDataProvider.getOne<RecordType>(resource, params),
        getMany: <RecordType extends RaRecord = any>(resource, params) =>
            baseDataProvider.getMany<RecordType>(resource, params),
        getManyReference: <RecordType extends RaRecord = any>(
            resource,
            params
        ) =>
            baseDataProvider
                .getManyReference<RecordType>(resource, params)
                .catch(error => {
                    if (error.code === 1) {
                        // undefined collection error: hide the error and return an empty list instead
                        return { data: [], total: 0 };
                    } else {
                        throw error;
                    }
                }),

        // update methods need to persist changes in localStorage
        update: <RecordType extends RaRecord = any>(resource, params) => {
            updateLocalStorage(() => {
                const index = data[resource]?.findIndex(
                    record => record.id == params.id
                );
                data[resource][index] = {
                    ...data[resource][index],
                    ...params.data,
                };
            });
            return baseDataProvider.update<RecordType>(resource, params);
        },
        updateMany: (resource, params) => {
            updateLocalStorage(() => {
                params.ids.forEach(id => {
                    const index = data[resource]?.findIndex(
                        record => record.id == id
                    );
                    data[resource][index] = {
                        ...data[resource][index],
                        ...params.data,
                    };
                });
            });
            return baseDataProvider.updateMany(resource, params);
        },
        create: <RecordType extends Omit<RaRecord, 'id'> = any>(
            resource,
            params
        ) => {
            // we need to call the fakerest provider first to get the generated id
            return baseDataProvider
                .create<RecordType>(resource, params)
                .then(response => {
                    updateLocalStorage(() => {
                        if (!data.hasOwnProperty(resource)) {
                            data[resource] = [];
                        }
                        data[resource].push(response.data);
                    });
                    return response;
                });
        },
        delete: <RecordType extends RaRecord = any>(resource, params) => {
            updateLocalStorage(() => {
                const index = data[resource]?.findIndex(
                    record => record.id == params.id
                );
                pullAt(data[resource], [index]);
            });
            return baseDataProvider.delete<RecordType>(resource, params);
        },
        deleteMany: (resource, params) => {
            updateLocalStorage(() => {
                const indexes = params.ids.map(id =>
                    data[resource]?.findIndex(record => record.id == id)
                );
                pullAt(data[resource], indexes);
            });
            return baseDataProvider.deleteMany(resource, params);
        },
    };
};

export interface LocalStorageDataProviderParams {
    defaultData?: any;
    localStorageKey?: string;
    loggingEnabled?: boolean;
    localStorageUpdateDelay?: number;
}