package repositories

import (
	"fmt"
	"regexp"
	"strings"

	"nearle/models"
)

// Shift windows for till staff.
//
// Scoped by tenant *and* outlet in every statement rather than checked first,
// the same shape the till-user queries use: a console naming somebody else's
// shift id updates no rows and is told so, instead of quietly editing another
// shop's hours.

var posTimeOfDay = regexp.MustCompile(`^([01]\d|2[0-3]):[0-5]\d$`)

// normaliseShiftTime accepts what a time input actually sends.
//
// `<input type="time">` gives "07:00", some browsers and most hand-typed values
// give "07:00:00", and `ridershifts` already stores the seconds form. Both are
// reduced to `HH:MM` so a shift written by one client reads the same to another.
func normaliseShiftTime(raw string) (string, error) {
	t := strings.TrimSpace(raw)
	if t == "" {
		return "", fmt.Errorf("a start and end time are required")
	}
	if len(t) == 8 && strings.Count(t, ":") == 2 {
		t = t[:5]
	}
	if !posTimeOfDay.MatchString(t) {
		return "", fmt.Errorf("time must be 24-hour HH:MM; got %q", raw)
	}
	return t, nil
}

// ListStaffShifts returns the shifts a tenant's staff can be put on, newest
// last so a picker reads in the order they were created rather than
// alphabetically by name.
//
// ── Why the outlet is optional ──────────────────────────────────────────────
//
// A shift is a fact about how a BUSINESS runs, not about one shop: a tenant
// that works 07:00–15:00 and 15:00–23:00 works those hours at every branch it
// owns, and making somebody re-enter them per outlet guarantees the third
// branch gets 07:00–15:30 and nobody notices. `locationid = 0` is a shift that
// belongs to the whole tenant.
//
// Branch-specific rows are still honoured, because they already exist and a
// tenant may genuinely run one outlet differently. Asking for an outlet returns
// the tenant's shifts AND that outlet's own; asking for none returns everything
// the tenant has.
func (r *posRepository) ListStaffShifts(tenantID, locationID int, includeInactive bool) ([]models.StaffShifts, error) {
	if tenantID <= 0 {
		return nil, fmt.Errorf("tenantid is required")
	}

	shifts := make([]models.StaffShifts, 0)
	args := []any{tenantID}

	query := `SELECT * FROM staffshifts WHERE tenantid = ?`
	if locationID > 0 {
		// The tenant-wide ones and this outlet's, never another outlet's.
		query += ` AND (COALESCE(locationid, 0) = 0 OR locationid = ?)`
		args = append(args, locationID)
	}
	if !includeInactive {
		query += ` AND LOWER(COALESCE(status,'active')) <> 'inactive'`
	}
	query += ` ORDER BY staffshiftid`

	if err := r.db.Raw(query, args...).Scan(&shifts).Error; err != nil {
		return nil, err
	}
	return shifts, nil
}

// CreateStaffShift adds a window at one outlet.
func (r *posRepository) CreateStaffShift(tenantID, locationID int, req models.StaffShifts) (*models.StaffShifts, error) {
	if tenantID <= 0 {
		return nil, fmt.Errorf("tenantid is required")
	}
	// `locationid = 0` is deliberate and is now the ordinary case: the shift
	// belongs to the tenant and every branch it owns can use it. An outlet is
	// only named when one shop really does run different hours.
	if locationID < 0 {
		locationID = 0
	}

	name := strings.TrimSpace(req.Name)
	if name == "" {
		return nil, fmt.Errorf("a shift name is required")
	}

	start, err := normaliseShiftTime(req.Starttime)
	if err != nil {
		return nil, err
	}
	end, err := normaliseShiftTime(req.Endtime)
	if err != nil {
		return nil, err
	}

	// An end before a start is allowed on purpose — a night shift runs 22:00 to
	// 06:00 and wrapping midnight is ordinary in retail. Only the equal case is
	// refused, because a zero-length window cannot be what anyone meant.
	if start == end {
		return nil, fmt.Errorf("a shift cannot start and end at the same time")
	}

	weekdays := strings.TrimSpace(req.Weekdays)
	if weekdays != "" && !regexp.MustCompile(`^[01]{7}$`).MatchString(weekdays) {
		return nil, fmt.Errorf("weekdays must be seven 0/1 characters starting Monday, e.g. 1111100")
	}

	shift := models.StaffShifts{
		Tenantid:   tenantID,
		Locationid: locationID,
		Name:       name,
		Starttime:  start,
		Endtime:    end,
		Weekdays:   weekdays,
		Status:     "Active",
	}
	if err := r.db.Table("staffshifts").Create(&shift).Error; err != nil {
		return nil, err
	}
	return &shift, nil
}

// UpdateStaffShift edits a window. Every field is optional; only the ones sent
// are written, matching how the till-user update behaves.
func (r *posRepository) UpdateStaffShift(tenantID, locationID int, req models.StaffShifts) (*models.StaffShifts, error) {
	if req.Staffshiftid <= 0 {
		return nil, fmt.Errorf("staff_shift_id is required")
	}

	sets := []string{}
	args := []interface{}{}

	if name := strings.TrimSpace(req.Name); name != "" {
		sets = append(sets, "name = ?")
		args = append(args, name)
	}
	if strings.TrimSpace(req.Starttime) != "" {
		t, err := normaliseShiftTime(req.Starttime)
		if err != nil {
			return nil, err
		}
		sets = append(sets, "starttime = ?")
		args = append(args, t)
	}
	if strings.TrimSpace(req.Endtime) != "" {
		t, err := normaliseShiftTime(req.Endtime)
		if err != nil {
			return nil, err
		}
		sets = append(sets, "endtime = ?")
		args = append(args, t)
	}
	if w := strings.TrimSpace(req.Weekdays); w != "" {
		if !regexp.MustCompile(`^[01]{7}$`).MatchString(w) {
			return nil, fmt.Errorf("weekdays must be seven 0/1 characters starting Monday")
		}
		sets = append(sets, "weekdays = ?")
		args = append(args, w)
	}
	if s := strings.TrimSpace(req.Status); s != "" {
		sets = append(sets, "status = ?")
		args = append(args, s)
	}

	if len(sets) == 0 {
		return nil, fmt.Errorf("nothing to change")
	}

	sets = append(sets, "updated = NOW()")
	args = append(args, req.Staffshiftid, tenantID, locationID)

	res := r.db.Exec(
		fmt.Sprintf(`UPDATE staffshifts SET %s WHERE staffshiftid = ? AND tenantid = ? AND locationid = ?`,
			strings.Join(sets, ", ")), args...)
	if res.Error != nil {
		return nil, res.Error
	}
	if res.RowsAffected == 0 {
		return nil, fmt.Errorf("no shift %d at this outlet", req.Staffshiftid)
	}

	var out models.StaffShifts
	if err := r.db.Raw(`SELECT * FROM staffshifts WHERE staffshiftid = ?`, req.Staffshiftid).Scan(&out).Error; err != nil {
		return nil, err
	}
	return &out, nil
}