import { Injectable, NotFoundException } from "@nestjs/common";
import { PrismaService } from "src/prisma/prisma.service";
import { GetShiftDto } from "../dtos/get-shift.dto";
import { toStringFromDate, toStringFromHHmm } from "../helpers/shifts-date-time-helpers";

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

    //fetch a shift using shift_id and return all that shift's info
    async getShiftByShiftId(shift_ids: number[]): Promise<GetShiftDto[]> {
        if(!Array.isArray(shift_ids) || shift_ids.length === 0) return [];

        const rows = await this.prisma.shifts.findMany({
            where: { id: { in: shift_ids } },
            select: {
                id:           true,
                timesheet_id: true,
                bank_code_id: true,
                date:         true,
                start_time:   true,
                end_time:     true,
                is_remote:    true,
                is_approved:  true,
                comment:      true,
            }
        });

        if(rows.length !== shift_ids.length) {
            const found_ids   = new Set(rows.map(row => row.id));
            const missing_ids = shift_ids.filter(id => !found_ids.has(id));
            throw new NotFoundException(`Shift(s) not found: ${ missing_ids.join(", ")}`); 
        }

        const row_by_id = new Map(rows.map(row => [row.id, row]));
        
        return shift_ids.map((id) => {
            const shift = row_by_id.get(id)!;
            return {
                timesheet_id: shift.timesheet_id,
                bank_code_id: shift.bank_code_id,
                date:         toStringFromDate(shift.date),
                start_time:   toStringFromHHmm(shift.start_time),
                end_time:     toStringFromHHmm(shift.end_time),
                is_remote:    shift.is_remote,
                is_approved:  shift.is_approved,
                comment:      shift.comment ?? undefined,
            } satisfies GetShiftDto;
        });
        
        
        
    }
}