import EventEmitter from 'events';
import { Knex } from 'knex';
import {
    FeatureEnvironmentKey,
    IFeatureEnvironmentStore,
} from '../types/stores/feature-environment-store';
import { Logger, LogProvider } from '../logger';
import metricsHelper from '../util/metrics-helper';
import { DB_TIME } from '../metric-events';
import { IFeatureEnvironment } from '../types/model';
import NotFoundError from '../error/notfound-error';

const T = {
    featureEnvs: 'feature_environments',
    featureStrategies: 'feature_strategies',
};

interface IFeatureEnvironmentRow {
    environment: string;
    feature_name: string;
    enabled: boolean;
}

export class FeatureEnvironmentStore implements IFeatureEnvironmentStore {
    private db: Knex;

    private logger: Logger;

    private readonly timer: Function;

    constructor(db: Knex, eventBus: EventEmitter, getLogger: LogProvider) {
        this.db = db;
        this.logger = getLogger('feature-environment-store.ts');
        this.timer = (action) =>
            metricsHelper.wrapTimer(eventBus, DB_TIME, {
                store: 'feature-environments',
                action,
            });
    }

    async delete({
        featureName,
        environment,
    }: FeatureEnvironmentKey): Promise<void> {
        await this.db(T.featureEnvs)
            .where('feature_name', featureName)
            .andWhere('environment', environment)
            .del();
    }

    async deleteAll(): Promise<void> {
        await this.db(T.featureEnvs).del();
    }

    destroy(): void {}

    async exists({
        featureName,
        environment,
    }: FeatureEnvironmentKey): Promise<boolean> {
        const result = await this.db.raw(
            `SELECT EXISTS (SELECT 1 FROM ${T.featureEnvs} WHERE feature_name = ? AND environment = ?) AS present`,
            [featureName, environment],
        );
        const { present } = result.rows[0];
        return present;
    }

    async get({
        featureName,
        environment,
    }: FeatureEnvironmentKey): Promise<IFeatureEnvironment> {
        const md = await this.db(T.featureEnvs)
            .where('feature_name', featureName)
            .andWhere('environment', environment)
            .first();
        if (md) {
            return {
                enabled: md.enabled,
                featureName,
                environment,
            };
        }
        throw new NotFoundError(
            `Could not find ${featureName} in ${environment}`,
        );
    }

    async getAll(): Promise<IFeatureEnvironment[]> {
        const rows = await this.db(T.featureEnvs);
        return rows.map((r) => ({
            enabled: r.enabled,
            featureName: r.feature_name,
            environment: r.environment,
        }));
    }

    async disableEnvironmentIfNoStrategies(
        featureName: string,
        environment: string,
    ): Promise<void> {
        const result = await this.db.raw(
            `SELECT EXISTS (SELECT 1 FROM ${T.featureStrategies} WHERE feature_name = ? AND environment = ?) AS enabled`,
            [featureName, environment],
        );
        const { enabled } = result.rows[0];
        if (!enabled) {
            await this.db(T.featureEnvs)
                .update({ enabled: false })
                .where({ feature_name: featureName, environment });
        }
    }

    async addEnvironmentToFeature(
        featureName: string,
        environment: string,
        enabled: boolean = false,
    ): Promise<void> {
        await this.db('feature_environments')
            .insert({ feature_name: featureName, environment, enabled })
            .onConflict(['environment', 'feature_name'])
            .merge('enabled');
    }

    // TODO: move to project store.
    async disconnectFeatures(
        environment: string,
        project: string,
    ): Promise<void> {
        const featureSelector = this.db('features')
            .where({ project })
            .select('name');
        await this.db(T.featureEnvs)
            .where({ environment })
            .andWhere('feature_name', 'IN', featureSelector)
            .del();
        await this.db('feature_strategies').where({
            environment,
            project_name: project,
        });
    }

    async featureHasEnvironment(
        environment: string,
        featureName: string,
    ): Promise<boolean> {
        const result = await this.db.raw(
            `SELECT EXISTS (SELECT 1 FROM ${T.featureEnvs} WHERE feature_name = ? AND environment = ?)  AS present`,
            [featureName, environment],
        );
        const { present } = result.rows[0];
        return present;
    }

    async getEnvironmentMetaData(
        environment: string,
        featureName: string,
    ): Promise<IFeatureEnvironment> {
        const md = await this.db(T.featureEnvs)
            .where('feature_name', featureName)
            .andWhere('environment', environment)
            .first();
        if (md) {
            return {
                enabled: md.enabled,
                featureName,
                environment,
            };
        }
        throw new NotFoundError(
            `Could not find ${featureName} in ${environment}`,
        );
    }

    async isEnvironmentEnabled(
        featureName: string,
        environment: string,
    ): Promise<boolean> {
        const row = await this.db(T.featureEnvs)
            .select('enabled')
            .where({ feature_name: featureName, environment })
            .first();
        return row.enabled;
    }

    async removeEnvironmentForFeature(
        featureName: string,
        environment: string,
    ): Promise<void> {
        await this.db(T.featureEnvs)
            .where({ feature_name: featureName, environment })
            .del();
    }

    async setEnvironmentEnabledStatus(
        environment: string,
        featureName: string,
        enabled: boolean,
    ): Promise<number> {
        return this.db(T.featureEnvs).update({ enabled }).where({
            environment,
            feature_name: featureName,
            enabled: !enabled,
        });
    }

    async connectProject(
        environment: string,
        projectId: string,
    ): Promise<void> {
        await this.db('project_environments').insert({
            environment_name: environment,
            project_id: projectId,
        });
    }

    async connectFeatures(
        environment: string,
        projectId: string,
    ): Promise<void> {
        const featuresToEnable = await this.db('features')
            .select('name')
            .where({
                project: projectId,
            });
        const rows: IFeatureEnvironmentRow[] = featuresToEnable.map((f) => ({
            environment,
            feature_name: f.name,
            enabled: false,
        }));
        if (rows.length > 0) {
            await this.db<IFeatureEnvironmentRow>('feature_environments')
                .insert(rows)
                .onConflict(['environment', 'feature_name'])
                .ignore();
        }
    }

    async disconnectProject(
        environment: string,
        projectId: string,
    ): Promise<void> {
        await this.db('project_environments')
            .where({ environment_name: environment, project_id: projectId })
            .del();
    }

    async connectFeatureToEnvironmentsForProject(
        featureName: string,
        projectId: string,
    ): Promise<void> {
        const environmentsToEnable = await this.db('project_environments')
            .select('environment_name')
            .where({ project_id: projectId });
        await Promise.all(
            environmentsToEnable.map(async (env) => {
                await this.db('feature_environments')
                    .insert({
                        environment: env.environment_name,
                        feature_name: featureName,
                        enabled: false,
                    })
                    .onConflict(['environment', 'feature_name'])
                    .ignore();
            }),
        );
    }
}