import { hhmmFromLocal, toDateOnly, toStringFromDate } from "src/modules/shared/helpers/date-time.helpers";
import { BadRequestException, Injectable } from "@nestjs/common";
import { ShiftsCommandService } from "src/modules/shifts/services/shifts-command.service";
import { PrismaService } from "src/prisma/prisma.service";
import { LeaveTypes } from "@prisma/client";

@Injectable()
export class LeaveRequestsUtils {
    constructor(
        private readonly prisma: PrismaService,
        private readonly shiftsCommand: ShiftsCommandService,
    ){}

    async syncShift(
        email:       string,
        employee_id: number,
        date:        string,
        hours:       number,
        type:        LeaveTypes,
        comment?:    string,
    ) {
        if (hours <= 0) return;

        const duration_minutes = Math.round(hours * 60);
        if (duration_minutes > 8 * 60) {
            throw new BadRequestException("Amount of hours cannot exceed 8 hours per day.");
        }
        const date_only = toDateOnly(date);
        const yyyy_mm_dd = toStringFromDate(date_only);



        const start_minutes = 8 * 60;
        const end_minutes = start_minutes + duration_minutes;
        const toHHmm = (total: number) =>
            `${String(Math.floor(total / 60)).padStart(2, "0")}:${String(total % 60).padStart(2, "0")}`;

        const existing = await this.prisma.shifts.findFirst({
            where: {
                date: date_only,
                bank_code: { type },
                timesheet: { employee_id: employee_id },
            },
            include: { bank_code: true },
        });

        await this.shiftsCommand.upsertShiftsByDate(email, {
            old_shift: existing
                ? {
                    date: yyyy_mm_dd,
                    start_time: existing.start_time.toISOString().slice(11, 16),
                    end_time:   existing.end_time.toISOString().slice(11, 16),
                    type:       existing.bank_code?.type ?? type,
                    is_remote:  existing.is_remote,
                    is_approved:existing.is_approved,
                    comment:    existing.comment ?? undefined,
                }
                : undefined,
            new_shift: {
                date: yyyy_mm_dd,
                start_time: toHHmm(start_minutes),
                end_time:   toHHmm(end_minutes),
                is_remote:  existing?.is_remote ?? false,
                is_approved:existing?.is_approved ?? false,
                comment:    comment ?? existing?.comment ?? "",
                type:       type,
            },
        });
    }

    async removeShift(
        email: string,
        employee_id: number,
        iso_date: string,
        type: LeaveTypes,
    ) {
        const date_only = toDateOnly(iso_date);
        const yyyy_mm_dd = toStringFromDate(date_only);
        const existing = await this.prisma.shifts.findFirst({
            where: {
                date: date_only,
                bank_code: { type },
                timesheet: { employee_id: employee_id },
            },
            include: { bank_code: true },
        });
        if (!existing) return;

        await this.shiftsCommand.upsertShiftsByDate(email, {
            old_shift: {
                date: yyyy_mm_dd,
                start_time: hhmmFromLocal(existing.start_time),
                end_time:   hhmmFromLocal(existing.end_time),
                type:       existing.bank_code?.type ?? type,
                is_remote:  existing.is_remote,
                is_approved:existing.is_approved,
                comment:    existing.comment ?? undefined,
            },
        });
    }

}