package middleware

import (
	"net/http"
	"net/url"
	"sort"

	"forge.cadoles.com/Cadoles/go-proxy"
	"forge.cadoles.com/Cadoles/go-proxy/util"
	"forge.cadoles.com/Cadoles/go-proxy/wildcard"
)

func RewriteHosts(mappings map[string]*url.URL) proxy.Middleware {
	patterns := make([]string, len(mappings))

	for p := range mappings {
		patterns = append(patterns, p)
	}

	sort.Strings(patterns)
	util.Reverse(patterns)

	return func(h http.Handler) http.Handler {
		fn := func(w http.ResponseWriter, r *http.Request) {
			var match *url.URL

			for _, p := range patterns {
				if matches := wildcard.Match(r.Host, p); !matches {
					continue
				}

				match = mappings[p]
				break
			}

			if match == nil {
				h.ServeHTTP(w, r)

				return
			}

			r.URL.Host = match.Host
			r.URL.Scheme = match.Scheme

			h.ServeHTTP(w, r)
		}

		return http.HandlerFunc(fn)
	}
}

func WithRewriteHosts(mappings map[string]*url.URL) proxy.OptionFunc {
	return func(o *proxy.Options) {
		o.Middlewares = append(o.Middlewares, RewriteHosts(mappings))
	}
}