package api

import (
	"net/http"
	"sort"
	"time"

	"github.com/alchemistkay/guestguard/internal/domain"
	"github.com/alchemistkay/guestguard/internal/storage"
)

// activityHandler serves the combined RSVP + access-check history for an
// event. The WebSocket hub only fans out *live* events to currently-
// connected dashboards; this endpoint is the catch-up channel for hosts
// who weren't watching when activity happened.
type activityHandler struct {
	events     *storage.EventRepo
	collabs    *storage.CollaboratorRepo
	rsvps      *storage.RSVPRepo
	accessLogs *storage.AccessLogRepo
}

type activityItem struct {
	Type      string    `json:"type"` // "rsvp" | "access_check"
	Timestamp time.Time `json:"ts"`
	GuestID   string    `json:"guest_id"`
	GuestName string    `json:"guest_name"`

	// RSVP-only
	Response string `json:"response,omitempty"`
	PlusOnes int    `json:"plus_ones,omitempty"`

	// Access-check-only
	Score   int    `json:"score,omitempty"`
	Band    string `json:"band,omitempty"`
	Blocked bool   `json:"blocked,omitempty"`
}

// GET /events/{id}/activity?limit=50
//
// Returns the most recent N activity items (RSVPs + scored access checks)
// for an event, sorted newest first. Frontends use this on dashboard mount
// to backfill the live monitor with history.
func (h *activityHandler) list(w http.ResponseWriter, r *http.Request) {
	hostID, ok := hostFromContext(w, r)
	if !ok {
		return
	}
	eventID, ok := parseIDParam(w, r, "id")
	if !ok {
		return
	}
	if _, _, ok := requireRole(w, r, h.events, h.collabs, eventID, hostID, domain.RoleViewer); !ok {
		return
	}

	limit := atoiOr(r.URL.Query().Get("limit"), 50)
	if limit <= 0 || limit > 200 {
		limit = 50
	}

	// Pull from each source. We grab `limit` from each so that after
	// merging we still have at least `limit` of the truly newest items.
	rsvps, err := h.rsvps.ListRecentByEvent(r.Context(), eventID, limit)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to load activity")
		return
	}
	checks, err := h.accessLogs.ListRecentScoredByEvent(r.Context(), eventID, limit)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to load activity")
		return
	}

	items := make([]activityItem, 0, len(rsvps)+len(checks))
	for _, a := range rsvps {
		items = append(items, activityItem{
			Type:      "rsvp",
			Timestamp: a.SubmittedAt,
			GuestID:   a.GuestID.String(),
			GuestName: a.GuestName,
			Response:  a.Response,
			PlusOnes:  a.PlusOnes,
		})
	}
	for _, c := range checks {
		items = append(items, activityItem{
			Type:      "access_check",
			Timestamp: c.CreatedAt,
			GuestID:   c.GuestID.String(),
			GuestName: c.GuestName,
			Score:     c.Score,
			Band:      bandFromScore(c.Score),
			Blocked:   c.Score >= 80,
		})
	}

	sort.Slice(items, func(i, j int) bool {
		return items[i].Timestamp.After(items[j].Timestamp)
	})
	if len(items) > limit {
		items = items[:limit]
	}

	writeJSON(w, http.StatusOK, map[string]any{
		"activity": items,
	})
}

// bandFromScore mirrors the friendly buckets used by the live WebSocket
// pipeline so backfilled items and live items render the same way in the
// dashboard feed. Thresholds match the fraud engine's intent: 0–29 looks
// normal, 30–59 worth a glance, 60–79 suspicious, ≥80 blocked.
func bandFromScore(score int) string {
	switch {
	case score >= 80:
		return "block"
	case score >= 60:
		return "high"
	case score >= 30:
		return "medium"
	default:
		return "low"
	}
}