Implement time off management (Issue #3)

Add full time-off lifecycle: create/edit/delete with shift conflict
detection, auto-removal from conflicting shifts with admin notification,
shift restoration on admin delete, and hard block on assigning volunteers
with approved time off to shifts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/timeoff/handler.go

@@ -1,22 +1,56 @@
 package timeoff
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"net/http"
 	"strconv"
+	"time"
 
 	"git.unsupervised.ca/walkies/internal/respond"
 	"git.unsupervised.ca/walkies/internal/server/middleware"
 	"github.com/go-chi/chi/v5"
 )
 
-type Handler struct {
-	store *Store
+// Notifier is the subset of notification.Store the handler needs.
+type Notifier interface {
+	CreateNotification(ctx context.Context, volunteerID int64, message string) error
 }
 
-func NewHandler(store *Store) *Handler {
-	return &Handler{store: store}
+// AdminLister returns admin volunteer IDs so the handler can notify them.
+type AdminLister interface {
+	ListAdminIDs(ctx context.Context) ([]int64, error)
+}
+
+// Storer is the interface the Handler depends on.
+type Storer interface {
+	Create(ctx context.Context, volunteerID int64, in CreateInput) (*Request, error)
+	GetByID(ctx context.Context, id int64) (*Request, error)
+	List(ctx context.Context, volunteerID int64) ([]Request, error)
+	Review(ctx context.Context, id, reviewerID int64, status string) (*Request, error)
+	Update(ctx context.Context, id int64, in UpdateInput) (*Request, error)
+	Delete(ctx context.Context, id int64) error
+	ConflictingShifts(ctx context.Context, volunteerID int64, startsAt, endsAt string) ([]ConflictingShift, error)
+	RemoveFromConflictingShifts(ctx context.Context, timeOffID, volunteerID int64, startsAt, endsAt string) ([]ConflictingShift, error)
+	RemovedShiftsForTimeOff(ctx context.Context, timeOffID int64) ([]ConflictingShift, error)
+	RestoreRemovedShifts(ctx context.Context, timeOffID int64) ([]ConflictingShift, error)
+}
+
+type Handler struct {
+	store       Storer
+	notifier    Notifier
+	adminLister AdminLister
+}
+
+func NewHandler(store *Store, notifier Notifier, adminLister AdminLister) *Handler {
+	return &Handler{store: store, notifier: notifier, adminLister: adminLister}
+}
+
+// NewHandlerFromInterfaces constructs a Handler from interface values, intended for testing.
+func NewHandlerFromInterfaces(store Storer, notifier Notifier, adminLister AdminLister) *Handler {
+	return &Handler{store: store, notifier: notifier, adminLister: adminLister}
 }
 
 // GET /api/v1/timeoff
@@ -38,6 +72,9 @@ func (h *Handler) List(w http.ResponseWriter, r *http.Request) {
 }
 
 // POST /api/v1/timeoff
+// Creates time off with status "approved". If confirm_conflicts is true and the
+// volunteer is assigned to shifts in the date range, they are auto-removed and
+// admins are notified (FR-T03).
 func (h *Handler) Create(w http.ResponseWriter, r *http.Request) {
 	claims := middleware.ClaimsFromContext(r.Context())
 	var in CreateInput
@@ -49,14 +86,181 @@ func (h *Handler) Create(w http.ResponseWriter, r *http.Request) {
 		respond.Error(w, http.StatusBadRequest, "starts_at and ends_at are required")
 		return
 	}
-	req, err := h.store.Create(r.Context(), claims.VolunteerID, in)
+
+	// Determine target volunteer (admin can create for others, FR-T05)
+	targetVolunteerID := claims.VolunteerID
+	if in.VolunteerID > 0 && claims.Role == "admin" {
+		targetVolunteerID = in.VolunteerID
+	}
+
+	// Check for conflicting shifts
+	conflicts, err := h.store.ConflictingShifts(r.Context(), targetVolunteerID, in.StartsAt, in.EndsAt)
+	if err != nil {
+		respond.Error(w, http.StatusInternalServerError, "could not check conflicts")
+		return
+	}
+
+	// If there are conflicts and the user hasn't confirmed, return them
+	if len(conflicts) > 0 && !in.ConfirmConflicts {
+		respond.JSON(w, http.StatusConflict, map[string]any{
+			"message":    "Time off conflicts with assigned shifts. Confirm to proceed.",
+			"conflicts":  conflicts,
+		})
+		return
+	}
+
+	// Create with auto-approved status
+	req, err := h.store.Create(r.Context(), targetVolunteerID, in)
 	if err != nil {
 		respond.Error(w, http.StatusInternalServerError, "could not create time off request")
 		return
 	}
+
+	// Auto-approve
+	req, err = h.store.Review(r.Context(), req.ID, claims.VolunteerID, "approved")
+	if err != nil {
+		respond.Error(w, http.StatusInternalServerError, "could not approve time off request")
+		return
+	}
+
+	// Remove from conflicting shifts (FR-T03)
+	if len(conflicts) > 0 {
+		removed, err := h.store.RemoveFromConflictingShifts(r.Context(), req.ID, targetVolunteerID, in.StartsAt, in.EndsAt)
+		if err != nil {
+			respond.Error(w, http.StatusInternalServerError, "could not remove from conflicting shifts")
+			return
+		}
+		// Notify admins
+		h.notifyAdmins(r.Context(), targetVolunteerID, removed)
+	}
+
 	respond.JSON(w, http.StatusCreated, req)
 }
 
+// PUT /api/v1/timeoff/{id}
+// Volunteers can edit their own future time off (FR-T02). Admins can edit any (FR-T05).
+func (h *Handler) Update(w http.ResponseWriter, r *http.Request) {
+	claims := middleware.ClaimsFromContext(r.Context())
+	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
+	if err != nil {
+		respond.Error(w, http.StatusBadRequest, "invalid id")
+		return
+	}
+
+	existing, err := h.store.GetByID(r.Context(), id)
+	if errors.Is(err, ErrNotFound) {
+		respond.Error(w, http.StatusNotFound, "time off request not found")
+		return
+	}
+	if err != nil {
+		respond.Error(w, http.StatusInternalServerError, "could not get time off request")
+		return
+	}
+
+	// Permission: volunteers can only edit their own future time off
+	if claims.Role != "admin" {
+		if existing.VolunteerID != claims.VolunteerID {
+			respond.Error(w, http.StatusForbidden, "cannot edit another volunteer's time off")
+			return
+		}
+		if !existing.StartsAt.After(time.Now()) {
+			respond.Error(w, http.StatusForbidden, "cannot edit past time off")
+			return
+		}
+	}
+
+	var in UpdateInput
+	if err := json.NewDecoder(r.Body).Decode(&in); err != nil {
+		respond.Error(w, http.StatusBadRequest, "invalid request body")
+		return
+	}
+	if in.StartsAt == "" || in.EndsAt == "" {
+		respond.Error(w, http.StatusBadRequest, "starts_at and ends_at are required")
+		return
+	}
+
+	req, err := h.store.Update(r.Context(), id, in)
+	if err != nil {
+		respond.Error(w, http.StatusInternalServerError, "could not update time off request")
+		return
+	}
+	respond.JSON(w, http.StatusOK, req)
+}
+
+// DELETE /api/v1/timeoff/{id}
+// Volunteers can delete their own future time off (FR-T02).
+// Admin delete restores the volunteer to previously removed shifts (FR-T04).
+func (h *Handler) Delete(w http.ResponseWriter, r *http.Request) {
+	claims := middleware.ClaimsFromContext(r.Context())
+	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
+	if err != nil {
+		respond.Error(w, http.StatusBadRequest, "invalid id")
+		return
+	}
+
+	existing, err := h.store.GetByID(r.Context(), id)
+	if errors.Is(err, ErrNotFound) {
+		respond.Error(w, http.StatusNotFound, "time off request not found")
+		return
+	}
+	if err != nil {
+		respond.Error(w, http.StatusInternalServerError, "could not get time off request")
+		return
+	}
+
+	// Permission: volunteers can only delete their own future time off
+	if claims.Role != "admin" {
+		if existing.VolunteerID != claims.VolunteerID {
+			respond.Error(w, http.StatusForbidden, "cannot delete another volunteer's time off")
+			return
+		}
+		if !existing.StartsAt.After(time.Now()) {
+			respond.Error(w, http.StatusForbidden, "cannot delete past time off")
+			return
+		}
+	}
+
+	// If admin is deleting, restore volunteer to removed shifts (FR-T04)
+	var restored []ConflictingShift
+	if claims.Role == "admin" {
+		restored, err = h.store.RestoreRemovedShifts(r.Context(), id)
+		if err != nil {
+			respond.Error(w, http.StatusInternalServerError, "could not restore shifts")
+			return
+		}
+	}
+
+	if err := h.store.Delete(r.Context(), id); err != nil {
+		respond.Error(w, http.StatusInternalServerError, "could not delete time off request")
+		return
+	}
+
+	respond.JSON(w, http.StatusOK, map[string]any{
+		"deleted":         true,
+		"restored_shifts": restored,
+	})
+}
+
+// GET /api/v1/timeoff/{id}/shifts
+// Returns shifts that were removed due to this time-off request (preview for FR-T04).
+func (h *Handler) RemovedShifts(w http.ResponseWriter, r *http.Request) {
+	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
+	if err != nil {
+		respond.Error(w, http.StatusBadRequest, "invalid id")
+		return
+	}
+
+	shifts, err := h.store.RemovedShiftsForTimeOff(r.Context(), id)
+	if err != nil {
+		respond.Error(w, http.StatusInternalServerError, "could not get removed shifts")
+		return
+	}
+	if shifts == nil {
+		shifts = []ConflictingShift{}
+	}
+	respond.JSON(w, http.StatusOK, shifts)
+}
+
 // PUT /api/v1/timeoff/{id}/review
 func (h *Handler) Review(w http.ResponseWriter, r *http.Request) {
 	claims := middleware.ClaimsFromContext(r.Context())
@@ -85,3 +289,19 @@ func (h *Handler) Review(w http.ResponseWriter, r *http.Request) {
 	}
 	respond.JSON(w, http.StatusOK, req)
 }
+
+// notifyAdmins sends a notification to all admin users about a volunteer's
+// shift removals due to time off (FR-T03).
+func (h *Handler) notifyAdmins(ctx context.Context, volunteerID int64, removed []ConflictingShift) {
+	if len(removed) == 0 {
+		return
+	}
+	adminIDs, err := h.adminLister.ListAdminIDs(ctx)
+	if err != nil {
+		return
+	}
+	msg := fmt.Sprintf("Volunteer %d has been removed from %d shift(s) due to time off.", volunteerID, len(removed))
+	for _, aid := range adminIDs {
+		h.notifier.CreateNotification(ctx, aid, msg) //nolint:errcheck
+	}
+}