// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

import {MM_TABLES} from '@constants/database';
import {Q} from '@nozbe/watermelondb';
import Model from '@nozbe/watermelondb/Model';

import App from '@typings/database/app';
import CustomEmoji from '@typings/database/custom_emoji';
import {
    DataFactory,
    RawApp,
    RawCustomEmoji,
    RawGlobal,
    RawRole,
    RawServers,
    RawSystem,
    RawTermsOfService,
} from '@typings/database/database';
import Global from '@typings/database/global';
import Role from '@typings/database/role';
import Servers from '@typings/database/servers';
import System from '@typings/database/system';
import TermsOfService from '@typings/database/terms_of_service';

import {OperationType} from './index';

const {APP, GLOBAL, SERVERS} = MM_TABLES.DEFAULT;
const {CUSTOM_EMOJI, ROLE, SYSTEM, TERMS_OF_SERVICE} = MM_TABLES.SERVER;

/**
 * operateAppRecord: Prepares record of entity 'App' from the DEFAULT database for update or create actions.
 * @param {DataFactory} operator
 * @param {Database} operator.db
 * @param {OperationType} operator.optType
 * @param {RecordValue} operator.value
 * @returns {Promise<void>}
 */
export const operateAppRecord = async ({db, optType, value}: DataFactory) => {
    const record = value as RawApp;

    const generator = (app: App) => {
        app._raw.id = record?.id ?? app.id;
        app.buildNumber = record?.buildNumber ?? '';
        app.createdAt = record?.createdAt ?? 0;
        app.versionNumber = record?.versionNumber ?? '';
    };

    return operateBaseRecord({db, optType, tableName: APP, value, generator});
};

/**
 * operateGlobalRecord: Prepares record of entity 'Global' from the DEFAULT database for update or create actions.
 * @param {DataFactory} operator
 * @param {Database} operator.db
 * @param {OperationType} operator.optType
 * @param {RecordValue} operator.value
 * @returns {Promise<void>}
 */
export const operateGlobalRecord = async ({db, optType, value}: DataFactory) => {
    const record = value as RawGlobal;

    const generator = (global: Global) => {
        global._raw.id = record?.id ?? global.id;
        global.name = record?.name ?? '';
        global.value = record?.value ?? 0;
    };

    return operateBaseRecord({db, optType, tableName: GLOBAL, value, generator});
};

/**
 * operateServersRecord: Prepares record of entity 'Servers' from the DEFAULT database for update or create actions.
 * @param {DataFactory} operator
 * @param {Database} operator.db
 * @param {OperationType} operator.optType
 * @param {RecordValue} operator.value
 * @returns {Promise<void>}
 */
export const operateServersRecord = async ({db, optType, value}: DataFactory) => {
    const record = value as RawServers;

    const generator = (servers: Servers) => {
        servers._raw.id = record?.id ?? servers.id;
        servers.dbPath = record?.dbPath ?? '';
        servers.displayName = record?.displayName ?? 0;
        servers.mentionCount = record?.mentionCount ?? 0;
        servers.unreadCount = record?.unreadCount ?? 0;
        servers.url = record?.url ?? 0;
    };

    return operateBaseRecord({db, optType, tableName: SERVERS, value, generator});
};

/**
 * operateCustomEmojiRecord: Prepares record of entity 'CustomEmoji' from the SERVER database for update or create actions.
 * @param {DataFactory} operator
 * @param {Database} operator.db
 * @param {OperationType} operator.optType
 * @param {RecordValue} operator.value
 * @returns {Promise<void>}
 */
export const operateCustomEmojiRecord = async ({db, optType, value}: DataFactory) => {
    const record = value as RawCustomEmoji;

    const generator = (emoji: CustomEmoji) => {
        emoji._raw.id = record?.id ?? emoji.id;
        emoji.name = record?.name ?? '';
    };

    return operateBaseRecord({db, optType, tableName: CUSTOM_EMOJI, value, generator});
};

/**
 * operateRoleRecord: Prepares record of entity 'Role' from the SERVER database for update or create actions.
 * @param {DataFactory} operator
 * @param {Database} operator.db
 * @param {OperationType} operator.optType
 * @param {RecordValue} operator.value
 * @returns {Promise<void>}
 */
export const operateRoleRecord = async ({db, optType, value}: DataFactory) => {
    const record = value as RawRole;

    const generator = (role: Role) => {
        role._raw.id = record?.id ?? role.id;
        role.name = record?.name ?? '';
        role.permissions = record?.permissions ?? [];
    };

    return operateBaseRecord({db, optType, tableName: ROLE, value, generator});
};

/**
 * operateSystemRecord: Prepares record of entity 'System' from the SERVER database for update or create actions.
 * @param {DataFactory} operator
 * @param {Database} operator.db
 * @param {OperationType} operator.optType
 * @param {RecordValue} operator.value
 * @returns {Promise<void>}
 */
export const operateSystemRecord = async ({db, optType, value}: DataFactory) => {
    const record = value as RawSystem;

    const generator = (system: System) => {
        system._raw.id = record?.id ?? system.id;
        system.name = record?.name ?? '';
        system.value = record?.value ?? '';
    };

    return operateBaseRecord({db, optType, tableName: SYSTEM, value, generator});
};

/**
 * operateTermsOfServiceRecord: Prepares record of entity 'TermsOfService' from the SERVER database for update or create actions.
 * @param {DataFactory} operator
 * @param {Database} operator.db
 * @param {OperationType} operator.optType
 * @param {RecordValue} operator.value
 * @returns {Promise<void>}
 */
export const operateTermsOfServiceRecord = async ({db, optType, value}: DataFactory) => {
    const record = value as RawTermsOfService;

    const generator = (tos: TermsOfService) => {
        tos._raw.id = record?.id ?? tos.id;
        tos.acceptedAt = record?.acceptedAt ?? 0;
    };

    return operateBaseRecord({db, optType, tableName: TERMS_OF_SERVICE, value, generator});
};

/**
 * operateBaseRecord:  The 'id' of a record is key to this function. Please note that - at the moment - if WatermelonDB
 * encounters an existing record during a CREATE operation, it silently fails the operation.
 *
 * In our case, we check to see if we have an existing 'id' and if so, we'll update the record with the data.
 * For an UPDATE operation, we fetch the existing record using the 'id' value and then we do the update operation;
 * if no record is found for that 'id', we'll create it a new record.
 *
 * @param {DataFactory} operatorBase
 * @param {Database} operatorBase.db
 * @param {OperationType} operatorBase.optType
 * @param {string} operatorBase.tableName
 * @param {any} operatorBase.value
 * @param {((model: Model) => void)} operatorBase.generator
 * @returns {Promise<any>}
 */
const operateBaseRecord = async ({db, optType, tableName, value, generator}: DataFactory) => {
    // We query first to see if we have a record on that entity with the current value.id
    const appRecord = await db.collections.get(tableName!).query(Q.where('id', value.id)).fetch() as Model[];
    const isPresent = appRecord.length > 0;

    if ((isPresent && optType === OperationType.CREATE) || (isPresent && optType === OperationType.UPDATE)) {
        // Two possible scenarios:
        // 1. We are dealing with either duplicates here and if so, we'll update instead of create
        // 2. This is just a normal update operation
        const record = appRecord[0];
        return record.prepareUpdate(() => generator!(record));
    }

    if ((!isPresent && optType === OperationType.UPDATE) || (optType === OperationType.CREATE)) {
        // Two possible scenarios
        // 1. We don't have a record yet to update; so we create it
        // 2. This is just a normal create operation
        return db.collections.get(tableName!).prepareCreate(generator);
    }

    return null;
};