package main

import (
	"net/http"
	"net/http/httputil"
	"net/url"
)

// initInvProxy builds a streaming reverse proxy to the inventory-service.
// FlushInterval=-1 flushes writes immediately so SSE endpoints (the suitbuilder
// search stream) work. Connection errors map to 503, mirroring the Python
// service's "Inventory service unavailable".
func (s *Server) initInvProxy(target string) error {
	u, err := url.Parse(target)
	if err != nil {
		return err
	}
	rp := httputil.NewSingleHostReverseProxy(u)
	rp.FlushInterval = -1
	rp.ErrorHandler = func(w http.ResponseWriter, r *http.Request, err error) {
		s.log.Error("inventory proxy error", "err", err, "path", r.URL.Path)
		writeJSON(w, http.StatusServiceUnavailable, map[string]any{"detail": "Inventory service unavailable"})
	}
	s.invProxy = rp
	return nil
}

// proxyInv returns a handler that rewrites the request path (via rewrite) and
// forwards it to the inventory-service, preserving method, query, headers, and
// body. The original /inv/* prefix etc. is mapped to the upstream path.
func (s *Server) proxyInv(rewrite func(r *http.Request) string) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if s.invProxy == nil {
			writeJSON(w, http.StatusServiceUnavailable, map[string]any{"detail": "Inventory service unavailable"})
			return
		}
		r.URL.Path = rewrite(r)
		r.URL.RawPath = "" // force re-encode from the (decoded) Path
		s.invProxy.ServeHTTP(w, r)
	}
}

func (s *Server) registerProxyRoutes(mux *http.ServeMux) {
	mux.HandleFunc("GET /inventory/{character_name}", s.proxyInv(func(r *http.Request) string {
		return "/inventory/" + r.PathValue("character_name")
	}))
	mux.HandleFunc("GET /inventory-characters", s.proxyInv(func(r *http.Request) string {
		return "/characters/list"
	}))
	mux.HandleFunc("GET /search/items", s.proxyInv(func(r *http.Request) string {
		return "/search/items"
	}))
	mux.HandleFunc("GET /search/equipped/{character_name}", s.proxyInv(func(r *http.Request) string {
		return "/search/equipped/" + r.PathValue("character_name")
	}))
	mux.HandleFunc("GET /search/upgrades/{character_name}/{slot}", s.proxyInv(func(r *http.Request) string {
		return "/search/upgrades/" + r.PathValue("character_name") + "/" + r.PathValue("slot")
	}))
	mux.HandleFunc("GET /sets/list", s.proxyInv(func(r *http.Request) string {
		return "/sets/list"
	}))

	// /inv/test is a static liveness probe in the Python service.
	mux.HandleFunc("GET /inv/test", func(w http.ResponseWriter, r *http.Request) {
		writeJSON(w, http.StatusOK, map[string]any{"message": "Inventory proxy route is working"})
	})
	// Generic catch-all proxy: /inv/{path...} -> {SVC}/{path}. Covers GET and
	// POST (incl. the SSE suitbuilder search). Registered for both methods.
	invAll := s.proxyInv(func(r *http.Request) string {
		return "/" + r.PathValue("path")
	})
	mux.HandleFunc("GET /inv/{path...}", invAll)
	mux.HandleFunc("POST /inv/{path...}", invAll)
}