/*
 * Copyright (C) Contributors to the Suwayomi project
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

import { mutate } from 'swr';
import client from 'util/client';

const APP_METADATA_KEY_PREFIX = 'webUI_';

const migrations: IMetadataMigration[] = [
    {
        keys: [{ oldKey: 'loadNextonEnding', newKey: 'loadNextOnEnding' }],
    },
];

const getMetadataKey = (key: string, appPrefix: string = APP_METADATA_KEY_PREFIX) => `${appPrefix}${key}`;

const doesMetadataKeyExistIn = (meta: IMetadata | undefined, key: string, appPrefix?: string): boolean =>
    Object.prototype.hasOwnProperty.call(meta ?? {}, getMetadataKey(key, appPrefix));

const convertValueFromMetadata = <T extends AllowedMetadataValueTypes = AllowedMetadataValueTypes>(
    value: string,
): T => {
    if (!Number.isNaN(+value)) {
        return +value as T;
    }

    if (value === 'true' || value === 'false') {
        return (value === 'true') as T;
    }

    if (value === 'undefined') {
        return undefined as T;
    }

    return value as T;
};

const getAppMetadataFrom = (meta: IMetadata, appPrefix: string = APP_METADATA_KEY_PREFIX): IMetadata => {
    const appMetadata: IMetadata = {};

    Object.entries(meta).forEach(([key, value]) => {
        if (key.startsWith(appPrefix)) {
            appMetadata[key] = value;
        }
    });

    return appMetadata;
};

const applyAppKeyPrefixMigration = (meta: IMetadata, migration: IMetadataMigration): IMetadata => {
    const migratedMetadata: IMetadata = { ...meta };

    if (!migration.appKeyPrefix) {
        return migratedMetadata;
    }

    const { oldPrefix, newPrefix } = migration.appKeyPrefix;

    const oldAppMetadata = getAppMetadataFrom(meta, oldPrefix);
    const newAppMetadata = getAppMetadataFrom(meta, newPrefix);

    const missingMetadataKeys = Object.keys(oldAppMetadata).filter((key) => !Object.keys(newAppMetadata).includes(key));

    const isMissingOldMetadata = missingMetadataKeys.length;
    if (isMissingOldMetadata) {
        missingMetadataKeys.forEach((oldKey) => {
            const keyWithNewPrefix = oldKey.replace(oldPrefix, newPrefix);
            migratedMetadata[keyWithNewPrefix] = oldAppMetadata[oldKey];
        });
    }

    return migratedMetadata;
};

const applyMetadataKeyMigration = (meta: IMetadata, migration: IMetadataMigration): IMetadata => {
    const migratedMetadata: IMetadata = { ...meta };

    if (!migration.keys) {
        return migratedMetadata;
    }

    const metadataKeyChanges = migration.keys;

    metadataKeyChanges.forEach(({ oldKey, newKey }) => {
        if (!doesMetadataKeyExistIn(meta, oldKey)) {
            return;
        }

        if (doesMetadataKeyExistIn(meta, newKey)) {
            return;
        }

        migratedMetadata[getMetadataKey(newKey)] = meta[getMetadataKey(oldKey)];
    });

    return migratedMetadata;
};

const applyMetadataMigrations = (meta?: IMetadata): IMetadata | undefined => {
    if (!meta) {
        return undefined;
    }

    const migrationToMetadata: [number, IMetadata][] = [[0, meta]];

    migrations.forEach((migration, index) => {
        const migrationId = index + 1;
        const metadataToMigrate = migrationToMetadata[migrationId - 1][1];
        const appKeyPrefixMigrated = applyAppKeyPrefixMigration(metadataToMigrate, migration);
        const metadataKeysMigrated = applyMetadataKeyMigration(appKeyPrefixMigrated, migration);

        migrationToMetadata.push([migrationId, metadataKeysMigrated]);
    });

    const appliedMigration = migrationToMetadata.length > 1;
    if (!appliedMigration) {
        return { ...meta };
    }

    return migrationToMetadata.pop()![1];
};

export const getMetadataValueFrom = <T extends AllowedMetadataValueTypes = AllowedMetadataValueTypes>(
    { meta }: IMetadataHolder,
    key: AppMetadataKeys,
    defaultValue?: T,
    applyMigrations: boolean = true,
): T | undefined => {
    const metadata = applyMigrations ? applyMetadataMigrations(meta) : meta;

    if (metadata === undefined || !doesMetadataKeyExistIn(metadata, key)) {
        return defaultValue;
    }

    return convertValueFromMetadata(metadata[getMetadataKey(key)]);
};

export const getMetadataFrom = (
    { meta }: IMetadataHolder,
    keysToDefaultValues: MetadataKeyValuePair[],
    applyMigrations?: boolean,
): IMetadata<AllowedMetadataValueTypes> => {
    const appMetadata: IMetadata<AllowedMetadataValueTypes> = {};

    keysToDefaultValues.forEach(([key, defaultValue]) => {
        appMetadata[key] = getMetadataValueFrom({ meta }, key, defaultValue, applyMigrations);
    });

    return appMetadata;
};

const wrapMetadataWithMetaKey = (wrap: boolean, metadata: IMetadata): IMetadataHolder => {
    if (wrap) {
        return {
            meta: {
                ...metadata,
            },
        };
    }

    return {
        ...metadata,
    };
};

export const requestUpdateMetadataValue = async (
    endpoint: string,
    metadataHolder: IMetadataHolder,
    key: AppMetadataKeys,
    value: AllowedMetadataValueTypes,
    endpointToMutate: string = endpoint,
    wrapWithMetaKey: boolean = true,
): Promise<void> => {
    const restApiVersion = '/api/v1';
    const url = `${restApiVersion}${endpoint}/meta`;
    const urlToMutate = `${restApiVersion}${endpointToMutate}`;

    const metadataKey = getMetadataKey(key);
    const valueAsString = `${value}`;

    const formData = new FormData();
    formData.append('key', metadataKey);
    formData.append('value', valueAsString);

    const mutatedMetadata = {
        ...metadataHolder.meta,
        [metadataKey]: valueAsString,
    };

    await client.patch(url, formData);
    await mutate(
        urlToMutate,
        { ...metadataHolder, ...wrapMetadataWithMetaKey(wrapWithMetaKey, mutatedMetadata) },
        { revalidate: false },
    );
};

export const requestUpdateMetadata = async (
    endpoint: string,
    metadataHolder: IMetadataHolder,
    keysToValues: [AppMetadataKeys, AllowedMetadataValueTypes][],
    endpointToMutate?: string,
    wrapWithMetaKey?: boolean,
): Promise<void[]> =>
    Promise.all(
        keysToValues.map(([key, value]) =>
            requestUpdateMetadataValue(endpoint, metadataHolder, key, value, endpointToMutate, wrapWithMetaKey),
        ),
    );

export const requestUpdateServerMetadata = async (
    serverMetadata: IMetadata,
    keysToValues: MetadataKeyValuePair[],
): Promise<void[]> => requestUpdateMetadata('', { meta: serverMetadata }, keysToValues, '/meta', false);

export const requestUpdateMangaMetadata = async (
    manga: IMangaCard | IManga,
    keysToValues: MetadataKeyValuePair[],
): Promise<void[]> => requestUpdateMetadata(`/manga/${manga.id}`, manga, keysToValues);

export const requestUpdateChapterMetadata = async (
    mangaChapter: IMangaChapter,
    keysToValues: MetadataKeyValuePair[],
): Promise<void[]> =>
    requestUpdateMetadata(
        `/manga/${mangaChapter.manga.id}/chapter/${mangaChapter.chapter.index}`,
        mangaChapter.chapter,
        keysToValues,
    );

export const requestUpdateCategoryMetadata = async (
    category: ICategory,
    keysToValues: MetadataKeyValuePair[],
): Promise<void[]> => requestUpdateMetadata(`/category/${category.id}`, category, keysToValues);