import { useEmployeeStore } from "src/stores/employee-store";
import { useSchedulePresetsStore } from "src/stores/schedule-presets.store";
import { SchedulePreset } from "../models/schedule-presets.models";
import { isShiftOverlap } from "src/modules/timesheets/utils/shift.util";

export const useEmployeeListApi = () => {
    const employee_store = useEmployeeStore();
    const schedule_preset_store = useSchedulePresetsStore();

    const getEmployeeList = async (): Promise<void> => {
        employee_store.is_loading = true;

        const success = await employee_store.getEmployeeList();
        if (success) await schedule_preset_store.findSchedulePresetList();

        employee_store.is_loading = false;
    };

    const getEmployeeDetails = async (email: string): Promise<void> => {
        const success = await employee_store.getEmployeeDetails(email);
        if (success && employee_store.employee.preset_id !== null) {
            schedule_preset_store.setCurrentSchedulePreset(employee_store.employee.preset_id ?? -1);
        }
    }

    const setSchedulePreset = (preset_id: number) => {
        schedule_preset_store.setCurrentSchedulePreset(preset_id);
        employee_store.employee.preset_id = preset_id < 0 ? null : preset_id;
    }

    const saveSchedulePreset = async () => {
        // Get the currently edited schedule preset from the store (frontend model)
        const preset = schedule_preset_store.current_schedule_preset;

        // Check if there's any overlap between shifts. If there is, is_error property
        // will be toggled to true and save process will stop
        for (const weekday of preset.weekdays) {
            weekday.is_error = isShiftOverlap(weekday.shifts);
        }

        if (preset.weekdays.some(weekday => weekday.is_error)) {
            return;
        } 
        
        // Flatten all weekday shifts into a single array
        const preset_shifts = preset.weekdays.flatMap(weekday => weekday.shifts);

        // Build a backend-compatible SchedulePreset instance
        const backend_preset = new SchedulePreset(
            preset.id, 
            preset.name, 
            preset_shifts
        );

        // Track whether the create/update operation succeeds
        let success = false;

        // Create a new preset if it has no backend ID, otherwise update the existing one
        if (preset.id === -1) 
            success = await schedule_preset_store.createSchedulePreset(backend_preset);
        else 
            success = await schedule_preset_store.updateSchedulePreset(backend_preset);

        // On success, refresh the preset list and close the preset manager UI
        if (success) {
            await schedule_preset_store.findSchedulePresetList();
            schedule_preset_store.is_manager_open = false;
        }
    }

    const deleteSchedulePreset = async (preset_id: number) => {
        const success = await schedule_preset_store.deleteSchedulePreset(preset_id);
        if (success) {
            await schedule_preset_store.findSchedulePresetList();
            schedule_preset_store.is_manager_open = false;
        }
    }

    return {
        getEmployeeList,
        getEmployeeDetails,
        setSchedulePreset,
        saveSchedulePreset,
        deleteSchedulePreset,
    };
};