'use server';

import { revalidatePath } from 'next/cache';
import { redirect } from 'next/navigation';
import clientPromise from './mongodb';
import { ObjectId } from 'mongodb';
import { BillingLocation } from './db-types';

/**
 * Server-side action which adds a new month to the database
 * @param locationId location of the bill
 * @param billId ID of the bill
 * @param prevState previous state of the form
 * @param formData form data
 * @returns 
 */
export async function addYearMonth(yearMonthString: string) {

    // update the bill in the mongodb
    const client = await clientPromise;
    const db = client.db("rezije");
    const yearMonth = parseInt(yearMonthString);

    const prevYearMonth = (yearMonth - 1) % 100  === 0 ? yearMonth - 89 : yearMonth - 1;

    // find all locations for the previous month
    const prevMonthLocations = await db.collection<BillingLocation>("lokacije").find({ yearMonth: prevYearMonth });

    const newMonthLocationsCursor = prevMonthLocations.map((prevLocation) => {
        return({
            // copy all the properties from the previous location
            ...prevLocation,
            // assign a new ID
            _id: (new ObjectId()).toHexString(),
            yearMonth,
            // copy bill array, but set all bills to unpaid and remove attachments and notes
            bills: prevLocation.bills.map((bill) => {
                return {
                    ...bill,
                    paid: false,
                    attachment: null,
                    notes: null,
                }
            })
        } as BillingLocation);
    });

    const newMonthLocations = await newMonthLocationsCursor.toArray()
    await db.collection<BillingLocation>("lokacije").insertMany(newMonthLocations);

    // clear the cache for the path
    revalidatePath('/');
    // go to the bill list
    redirect('/');
}

export async function gotoHome() {
    redirect('/');   
}

export const fetchBillById = async (locationID:string, billID:string) => {
    const client = await clientPromise;
    const db = client.db("rezije");

    // find a location with the given locationID
    const billLocation = await db.collection<BillingLocation>("lokacije").findOne({ _id: locationID })

    if(!billLocation) {
        console.log(`Location ${locationID} not found`);
        return(null);
    }

    // find a bill with the given billID
    const bill = billLocation?.bills.find(({ _id }) => _id.toString() === billID);

    if(!bill) {
        console.log('Bill not found');
        return(null);
    }

    return(bill);
}

export const deleteBillById = async (locationID:string, billID:string) => {
    const client = await clientPromise;
    const db = client.db("rezije");

    // find a location with the given locationID
    const post = await db.collection<BillingLocation>("lokacije").updateOne(
        {
            _id: locationID // find a location with the given locationID
        },
        {
            // remove the bill with the given billID
            $pull: {
                bills: {
                    _id: billID
                }
            }
        });
    
    return(post.modifiedCount);
}