package server

import (
	"encoding/json"
	"net/http"

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

	internacme "git.wntrmute.dev/kyle/metacrypt/internal/acme"
	"git.wntrmute.dev/kyle/metacrypt/internal/engine"
)

// registerACMERoutes adds ACME protocol and management routes to r.
func (s *Server) registerACMERoutes(r chi.Router) {
	// ACME protocol endpoints — HTTP only (RFC-defined protocol, no gRPC equivalent).
	r.Route("/acme/{mount}", func(r chi.Router) {
		r.Use(func(next http.Handler) http.Handler {
			return s.requireUnseal(next.ServeHTTP)
		})
		r.Get("/directory", s.acmeDispatch)
		r.Head("/new-nonce", s.acmeDispatch)
		r.Get("/new-nonce", s.acmeDispatch)
		r.Post("/new-account", s.acmeDispatch)
		r.Post("/new-order", s.acmeDispatch)
		r.Post("/authz/{id}", s.acmeDispatch)
		r.Post("/challenge/{type}/{id}", s.acmeDispatch)
		r.Post("/finalize/{id}", s.acmeDispatch)
		r.Post("/cert/{id}", s.acmeDispatch)
		r.Post("/revoke-cert", s.acmeDispatch)
	})

	// Management endpoints — require MCIAS auth; REST counterparts to ACMEService gRPC.
	r.Post("/v1/acme/{mount}/eab", s.requireAuth(s.handleACMECreateEAB))
	r.Put("/v1/acme/{mount}/config", s.requireAdmin(s.handleACMESetConfig))
	r.Get("/v1/acme/{mount}/accounts", s.requireAdmin(s.handleACMEListAccounts))
	r.Get("/v1/acme/{mount}/orders", s.requireAdmin(s.handleACMEListOrders))
}

// acmeDispatch routes an ACME protocol request to the correct mount handler.
func (s *Server) acmeDispatch(w http.ResponseWriter, r *http.Request) {
	mountName := chi.URLParam(r, "mount")
	h, err := s.getOrCreateACMEHandler(mountName)
	if err != nil {
		http.Error(w, `{"type":"urn:ietf:params:acme:error:malformed","detail":"unknown mount"}`,
			http.StatusNotFound)
		return
	}
	// Re-dispatch through the handler's own chi router.
	// Since we are already matched on the method+path, call the right method directly.
	// The handler's RegisterRoutes uses a sub-router; instead we create a fresh router
	// per request and serve it.
	sub := chi.NewRouter()
	h.RegisterRoutes(sub)
	// Strip the "/acme/{mount}" prefix before delegating.
	http.StripPrefix("/acme/"+mountName, sub).ServeHTTP(w, r)
}

// getOrCreateACMEHandler lazily creates an ACME handler for the named CA mount.
func (s *Server) getOrCreateACMEHandler(mountName string) (*internacme.Handler, error) {
	s.acmeMu.Lock()
	defer s.acmeMu.Unlock()
	if s.acmeHandlers == nil {
		s.acmeHandlers = make(map[string]*internacme.Handler)
	}
	if h, ok := s.acmeHandlers[mountName]; ok {
		return h, nil
	}
	// Verify mount is a CA engine.
	mount, err := s.engines.GetMount(mountName)
	if err != nil {
		return nil, err
	}
	if mount.Type != engine.EngineTypeCA {
		return nil, engine.ErrMountNotFound
	}
	// Build base URL from config.
	baseURL := s.cfg.Server.ExternalURL
	if baseURL == "" {
		baseURL = "https://" + s.cfg.Server.ListenAddr
	}
	h := internacme.NewHandler(mountName, s.seal.Barrier(), s.engines, baseURL, s.logger)
	s.acmeHandlers[mountName] = h
	return h, nil
}

// handleACMECreateEAB — POST /v1/acme/{mount}/eab
// Creates EAB credentials for the authenticated MCIAS user.
func (s *Server) handleACMECreateEAB(w http.ResponseWriter, r *http.Request) {
	mountName := chi.URLParam(r, "mount")
	info := TokenInfoFromContext(r.Context())

	h, err := s.getOrCreateACMEHandler(mountName)
	if err != nil {
		http.Error(w, `{"error":"mount not found"}`, http.StatusNotFound)
		return
	}

	cred, err := h.CreateEAB(r.Context(), info.Username)
	if err != nil {
		s.logger.Error("acme: create EAB", "error", err)
		http.Error(w, `{"error":"failed to create EAB credentials"}`, http.StatusInternalServerError)
		return
	}

	writeJSON(w, http.StatusCreated, map[string]interface{}{
		"kid":      cred.KID,
		"hmac_key": cred.HMACKey, // raw bytes; client should base64url-encode for ACME clients
	})
}

// handleACMESetConfig — PUT /v1/acme/{mount}/config
// Sets the default issuer for ACME certificate issuance on this mount.
func (s *Server) handleACMESetConfig(w http.ResponseWriter, r *http.Request) {
	mountName := chi.URLParam(r, "mount")

	var req struct {
		DefaultIssuer string `json:"default_issuer"`
	}
	if err := readJSON(r, &req); err != nil {
		http.Error(w, `{"error":"invalid request"}`, http.StatusBadRequest)
		return
	}
	if req.DefaultIssuer == "" {
		http.Error(w, `{"error":"default_issuer is required"}`, http.StatusBadRequest)
		return
	}

	h, err := s.getOrCreateACMEHandler(mountName)
	if err != nil {
		http.Error(w, `{"error":"mount not found"}`, http.StatusNotFound)
		return
	}

	cfg := &internacme.ACMEConfig{DefaultIssuer: req.DefaultIssuer}
	data, _ := json.Marshal(cfg)
	barrierPath := "acme/" + mountName + "/config.json"
	if err := s.seal.Barrier().Put(r.Context(), barrierPath, data); err != nil {
		s.logger.Error("acme: save config", "error", err)
		http.Error(w, `{"error":"failed to save config"}`, http.StatusInternalServerError)
		return
	}
	_ = h // handler exists; config is read from barrier on each request
	writeJSON(w, http.StatusOK, map[string]interface{}{"ok": true})
}

// handleACMEListAccounts — GET /v1/acme/{mount}/accounts
func (s *Server) handleACMEListAccounts(w http.ResponseWriter, r *http.Request) {
	mountName := chi.URLParam(r, "mount")
	h, err := s.getOrCreateACMEHandler(mountName)
	if err != nil {
		http.Error(w, `{"error":"mount not found"}`, http.StatusNotFound)
		return
	}
	accounts, err := h.ListAccounts(r.Context())
	if err != nil {
		s.logger.Error("acme: list accounts", "error", err)
		http.Error(w, `{"error":"internal error"}`, http.StatusInternalServerError)
		return
	}
	writeJSON(w, http.StatusOK, accounts)
}

// handleACMEListOrders — GET /v1/acme/{mount}/orders
func (s *Server) handleACMEListOrders(w http.ResponseWriter, r *http.Request) {
	mountName := chi.URLParam(r, "mount")
	h, err := s.getOrCreateACMEHandler(mountName)
	if err != nil {
		http.Error(w, `{"error":"mount not found"}`, http.StatusNotFound)
		return
	}
	orders, err := h.ListOrders(r.Context())
	if err != nil {
		s.logger.Error("acme: list orders", "error", err)
		http.Error(w, `{"error":"internal error"}`, http.StatusInternalServerError)
		return
	}
	writeJSON(w, http.StatusOK, orders)
}