package oppintel

import (
	"encoding/json"
	"errors"
	"net/http"
	"strconv"
	"strings"

	"github.com/go-chi/chi/v5"

	"github.com/missionworkforce/missionmatch/internal/platform/security"
)

// Handler serves the read API over the unified opportunity records catalog. Every route is gated by a
// capability (search.run, held by all roles) so a new endpoint never ships ungated.
type Handler struct{ svc *Service }

// NewHandler builds the handler.
func NewHandler(svc *Service) *Handler { return &Handler{svc: svc} }

// Routes mounts the opportunity intelligence endpoints under the /api group. The caller has already
// applied the session and CSRF middleware; this adds the per route capability gate.
func (h *Handler) Routes(r chi.Router) {
	r.With(security.RequireCapability(security.CapSearchRun)).Get("/opportunity-intelligence", h.list)
}

func (h *Handler) list(w http.ResponseWriter, r *http.Request) {
	f := Filters{
		Kinds:    multiVals(r, "kind"),
		NAICS:    multiVals(r, "naics"),
		Agencies: multiVals(r, "agency"),
		States:   multiVals(r, "state"),
		Limit:    intParam(r, "limit", 0),
	}
	items, err := h.svc.List(r.Context(), f)
	if err != nil {
		if errors.Is(err, ErrNoDatabase) {
			writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": "database not configured"})
			return
		}
		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "internal error"})
		return
	}
	writeJSON(w, http.StatusOK, items)
}

// multiVals collects a filter that may be repeated (?kind=a&kind=b) or comma listed (?kind=a,b).
func multiVals(r *http.Request, key string) []string {
	var out []string
	for _, v := range r.URL.Query()[key] {
		for _, p := range strings.Split(v, ",") {
			if p = strings.TrimSpace(p); p != "" {
				out = append(out, p)
			}
		}
	}
	return out
}

func intParam(r *http.Request, key string, def int) int {
	if v := strings.TrimSpace(r.URL.Query().Get(key)); v != "" {
		if n, err := strconv.Atoi(v); err == nil {
			return n
		}
	}
	return def
}

func writeJSON(w http.ResponseWriter, status int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(v)
}