package httpapi

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

	"github.com/descrybe/descrybe-v2/apps/api/internal/billing"
	"github.com/go-chi/chi/v5"
	"github.com/google/uuid"
)

// GET /api/billing/capabilities — effective plan ∩ global ∩ member features for the caller.
func (s *Server) handleGetCapabilities(w http.ResponseWriter, r *http.Request) {
	if s.Billing == nil {
		Error(w, http.StatusServiceUnavailable, "billing unavailable")
		return
	}
	cid, ok := CompanyIDFromContext(r.Context())
	if !ok {
		Error(w, http.StatusUnauthorized, "company required")
		return
	}
	// Member-aware: the company owner's per-member overlay narrows what this caller
	// sees, so nav / route guard / feature gates all hide the same surfaces at once.
	uid, _ := UserIDFromContext(r.Context())
	caps, err := s.Billing.CapabilitiesForMember(r.Context(), cid, uid)
	if err != nil {
		Error(w, http.StatusInternalServerError, "failed to load capabilities")
		return
	}
	etag := billing.CapabilitiesResponseETag(caps)
	// Private: company-scoped. Short max-age + ETag mirrors OpenAPI conditional GET pattern.
	w.Header().Set("Cache-Control", "private, max-age=30, must-revalidate")
	w.Header().Set("ETag", etag)
	if match := r.Header.Get("If-None-Match"); match != "" && match == etag {
		w.WriteHeader(http.StatusNotModified)
		return
	}
	JSON(w, http.StatusOK, caps)
}

// GET /api/admin/plans/{planID}/features
func (s *Server) handleAdminGetPlanFeatures(w http.ResponseWriter, r *http.Request) {
	if s.Billing == nil {
		Error(w, http.StatusServiceUnavailable, "billing unavailable")
		return
	}
	planID, err := strconv.ParseInt(strings.TrimSpace(chi.URLParam(r, "planID")), 10, 64)
	if err != nil || planID <= 0 {
		Error(w, http.StatusBadRequest, "invalid plan id")
		return
	}
	view, err := s.Billing.GetPlanFeatures(r.Context(), planID)
	if err != nil {
		writePlanFeaturesErr(w, "could not load plan features", err)
		return
	}
	w.Header().Set("Cache-Control", "private, no-store")
	JSON(w, http.StatusOK, view)
}

// PUT /api/admin/plans/{planID}/features — replaces stored feature overrides.
func (s *Server) handleAdminPutPlanFeatures(w http.ResponseWriter, r *http.Request) {
	if s.Billing == nil {
		Error(w, http.StatusServiceUnavailable, "billing unavailable")
		return
	}
	planID, err := strconv.ParseInt(strings.TrimSpace(chi.URLParam(r, "planID")), 10, 64)
	if err != nil || planID <= 0 {
		Error(w, http.StatusBadRequest, "invalid plan id")
		return
	}
	var body billing.PlanFeaturesUpdate
	if err := DecodeJSON(r, &body); err != nil {
		Error(w, http.StatusBadRequest, "invalid json")
		return
	}
	if body.Features == nil {
		Error(w, http.StatusBadRequest, "features required")
		return
	}
	view, err := s.Billing.SetPlanFeatures(r.Context(), planID, body.Features)
	if err != nil {
		writePlanFeaturesErr(w, "could not save plan features", err)
		return
	}
	JSON(w, http.StatusOK, view)
}

// POST /api/admin/plans/{planID}/features/enable-all — sets every registry key true (custom packages).
func (s *Server) handleAdminEnableAllPlanFeatures(w http.ResponseWriter, r *http.Request) {
	if s.Billing == nil {
		Error(w, http.StatusServiceUnavailable, "billing unavailable")
		return
	}
	planID, err := strconv.ParseInt(strings.TrimSpace(chi.URLParam(r, "planID")), 10, 64)
	if err != nil || planID <= 0 {
		Error(w, http.StatusBadRequest, "invalid plan id")
		return
	}
	view, err := s.Billing.EnableAllPlanFeatures(r.Context(), planID)
	if err != nil {
		writePlanFeaturesErr(w, "could not enable plan features", err)
		return
	}
	JSON(w, http.StatusOK, view)
}

// POST /api/admin/plans/{planID}/features/disable-all — sets every registry key false.
func (s *Server) handleAdminDisableAllPlanFeatures(w http.ResponseWriter, r *http.Request) {
	if s.Billing == nil {
		Error(w, http.StatusServiceUnavailable, "billing unavailable")
		return
	}
	planID, err := strconv.ParseInt(strings.TrimSpace(chi.URLParam(r, "planID")), 10, 64)
	if err != nil || planID <= 0 {
		Error(w, http.StatusBadRequest, "invalid plan id")
		return
	}
	view, err := s.Billing.DisableAllPlanFeatures(r.Context(), planID)
	if err != nil {
		writePlanFeaturesErr(w, "could not disable plan features", err)
		return
	}
	JSON(w, http.StatusOK, view)
}

// GET /api/admin/feature-gates
func (s *Server) handleAdminGetFeatureGates(w http.ResponseWriter, r *http.Request) {
	if s.Billing == nil {
		Error(w, http.StatusServiceUnavailable, "billing unavailable")
		return
	}
	view, err := s.Billing.GetFeatureGates(r.Context())
	if err != nil {
		Error(w, http.StatusInternalServerError, "failed to load feature gates")
		return
	}
	w.Header().Set("Cache-Control", "private, no-store")
	JSON(w, http.StatusOK, view)
}

// PUT /api/admin/feature-gates — partial upsert of section/feature master switches.
func (s *Server) handleAdminPutFeatureGates(w http.ResponseWriter, r *http.Request) {
	if s.Billing == nil {
		Error(w, http.StatusServiceUnavailable, "billing unavailable")
		return
	}
	var body billing.FeatureGatesUpdate
	if err := DecodeJSON(r, &body); err != nil {
		Error(w, http.StatusBadRequest, "invalid json")
		return
	}
	if body.Sections == nil && body.Features == nil {
		Error(w, http.StatusBadRequest, "sections or features required")
		return
	}
	var updatedBy *uuid.UUID
	if uid, ok := UserIDFromContext(r.Context()); ok {
		updatedBy = &uid
	}
	view, err := s.Billing.SetFeatureGates(r.Context(), body.Sections, body.Features, updatedBy)
	if err != nil {
		ClientOrLog(w, http.StatusBadRequest, "could not update feature gates", err, billing.ClientError)
		return
	}
	JSON(w, http.StatusOK, view)
}

// PUT /api/admin/feature-gates/sections/{section} — enable/disable a section for ALL plans.
func (s *Server) handleAdminPutFeatureGateSection(w http.ResponseWriter, r *http.Request) {
	if s.Billing == nil {
		Error(w, http.StatusServiceUnavailable, "billing unavailable")
		return
	}
	section := strings.TrimSpace(chi.URLParam(r, "section"))
	if section == "" {
		Error(w, http.StatusBadRequest, "section required")
		return
	}
	var body billing.SectionGateUpdate
	if err := DecodeJSON(r, &body); err != nil {
		Error(w, http.StatusBadRequest, "invalid json")
		return
	}
	if body.Enabled == nil {
		Error(w, http.StatusBadRequest, "enabled required")
		return
	}
	var updatedBy *uuid.UUID
	if uid, ok := UserIDFromContext(r.Context()); ok {
		updatedBy = &uid
	}
	view, err := s.Billing.SetSectionGate(r.Context(), section, *body.Enabled, updatedBy)
	if err != nil {
		ClientOrLog(w, http.StatusBadRequest, "could not update section gate", err, billing.ClientError)
		return
	}
	JSON(w, http.StatusOK, view)
}

// writePlanFeaturesErr maps known billing client errors to the correct status
// (404 for missing plan; 400 for validation).
func writePlanFeaturesErr(w http.ResponseWriter, publicFallback string, err error) {
	if errors.Is(err, billing.ErrPlanNotFound) {
		Error(w, http.StatusNotFound, billing.ErrPlanNotFound.Error())
		return
	}
	ClientOrLog(w, http.StatusBadRequest, publicFallback, err, billing.ClientError)
}