import { Injectable } from "@nestjs/common";
import { ExpensesArchive } from "@prisma/client";
import { PrismaService } from "src/prisma/prisma.service";

@Injectable()
export class ExpensesArchivalService {
    constructor(private readonly prisma: PrismaService){}

    async archiveOld(): Promise<void> {
        //fetches archived timesheet's Ids
        const archived_timesheets = await this.prisma.timesheetsArchive.findMany({
            select: { timesheet_id: true },
        });

        const timesheet_ids = archived_timesheets.map(sheet => sheet.timesheet_id);
        if(timesheet_ids.length === 0) {
            return;
        }

        // copy/delete transaction
        await this.prisma.$transaction(async transaction => {
            //fetches expenses to move to archive
            const expenses_to_archive = await transaction.expenses.findMany({
                where: { timesheet_id: { in: timesheet_ids } },
            });
            if(expenses_to_archive.length === 0) {
                return;
            }

            //copies sent to archive table
            await transaction.expensesArchive.createMany({
                data: expenses_to_archive.map(exp => ({
                    expense_id: exp.id,
                    timesheet_id: exp.timesheet_id,
                    bank_code_id: exp.bank_code_id,
                    date: exp.date,
                    amount: exp.amount,
                    attachment: exp.attachment,
                    comment: exp.comment,
                    is_approved: exp.is_approved,
                    supervisor_comment: exp.supervisor_comment,
                })),
            });

            //delete from expenses table
            await transaction.expenses.deleteMany({
                where: { id: { in: expenses_to_archive.map(exp => exp.id) } },
            })

        })
    }

    //fetches all archived timesheets
    async findAllArchived(): Promise<ExpensesArchive[]> {
    return this.prisma.expensesArchive.findMany();
    }

    //fetches an archived timesheet
    async findOneArchived(id: number): Promise<ExpensesArchive> {
    return this.prisma.expensesArchive.findUniqueOrThrow({ where: { id } });
    }
}