import { QueryResult } from "./model"



interface IDictionary<TValue> {
    [id: string]: TValue;
}

export async function listDatabases(client: any) {
    try {
        const databasesList = await client
            .db()
            .admin()
            .listDatabases({ nameOnly: true })
        return databasesList.databases.map((dbName: any) => dbName.name)
    } catch (e) {
        return console.error(e)
    }
}

export async function listCollections(client: any, dbname: string) {
    try {
        const databasesList = await (
            await client.db(dbname).listCollections().toArray()
        ).map((db: any) => db.name)
        return databasesList
    } catch (e) {
        return console.error(e)
    }
}

export async function listfields(
    client: any,
    dbname: string,
    collectionName: string
) {
    try {
        const keys: string[] = []
        await client.db(dbname).collection(collectionName).find().forEach((doc: any) =>{
            for (const key in doc) {
                if (keys.indexOf(key) < 0 && !key.startsWith('_')) {
                    keys.push(key)
                }
            }
        })

        return keys
    } catch (e) {
        return console.error(e)
    }
}


export async function query(
    client: any,
    dbname: string,
    collectionName: string,
    listoffields: string[],
    substitution: any
) {
    try {
        const projectionValues: IDictionary<boolean> = {'_id': false}
        let res = {}
        Object.keys(substitution).forEach((field) => {
            if(!listoffields.includes(field)){
                delete substitution[field]
            }
        })
        if(dbname && collectionName && listoffields.length){
            const result =   await client.db(dbname).collection(collectionName).find({}, {projection: projectionValues }).toArray();
            const objResult = new QueryResult(result, substitution, client, dbname, collectionName)
            res = await objResult.populate()
        }


        return res

    } catch (e) {
        return console.error(e)
    }
}