package website

import (
	"encoding/json"
	"net/http"
	"regexp"
	"slices"
	"strings"

	ihttp "go.alanpearce.eu/homestead/internal/http"
	"go.alanpearce.eu/homestead/internal/server"
	"go.alanpearce.eu/homestead/templates"

	"github.com/kevinpollet/nego"
)

func (website *Website) webfinger(w http.ResponseWriter, r *http.Request) *ihttp.Error {
	if r.URL.Query().Get("resource") == website.acctResource {
		w.Header().Add("Content-Type", "application/jrd+json")
		w.Header().Add("Access-Control-Allow-Origin", "*")
		if err := json.NewEncoder(w).Encode(website.me); err != nil {
			return &ihttp.Error{
				Code:  http.StatusInternalServerError,
				Cause: err,
			}
		}
	}

	return nil
}

func (website *Website) ErrorHandler(err *ihttp.Error, w http.ResponseWriter, r *http.Request) {
	if strings.Contains(r.Header.Get("Accept"), "text/html") {
		w.WriteHeader(err.Code)
		err := templates.Error(website.config, r.URL.Path, err).Render(r.Context(), w)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
		}
	} else {
		http.Error(w, err.Message, err.Code)
	}
}

func (website *Website) ServeHTTP(w http.ResponseWriter, r *http.Request) *ihttp.Error {
	urlPath, shouldRedirect := website.reader.CanonicalisePath(r.URL.Path)
	if shouldRedirect {
		website.counter.Count(r, "302")
		http.Redirect(w, r, urlPath, 302)

		return nil
	}
	file, err := website.reader.GetFile(urlPath)
	if err != nil {
		website.log.Warn("Error reading file", "error", err)

		return &ihttp.Error{
			Message: "Error reading file",
			Code:    http.StatusInternalServerError,
		}
	}
	if file == nil {
		website.counter.Count(r, "404")

		return &ihttp.Error{
			Message: "File not found",
			Code:    http.StatusNotFound,
		}
	}
	website.counter.Count(r, file.Title)
	w.Header().Add("ETag", file.Etag)
	w.Header().Add("Vary", "Accept-Encoding")
	csp := *website.config.CSP
	if file.StyleHash != "" {
		csp.StyleSrc = []string{"'" + file.StyleHash + "'"}
	}
	w.Header().Add("Content-Security-Policy", csp.String())
	for k, v := range website.config.Extra.Headers {
		w.Header().Add(k, v)
	}
	enc := nego.NegotiateContentEncoding(r, file.AvailableEncodings()...)
	if enc != "" {
		w.Header().Add("Content-Encoding", enc)
	}
	w.Header().Add("Content-Type", file.ContentType)
	http.ServeContent(w, r, file.Path, file.LastModified, file.Encodings[enc])

	return nil
}

func (website *Website) MakeRedirectorApp() *server.App {
	mux := http.NewServeMux()

	re := regexp.MustCompile(
		"^(.*)\\." + strings.ReplaceAll(website.config.WildcardDomain, ".", `\.`) + "$",
	)
	replace := "${1}." + website.config.Domains[0]
	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		switch {
		case slices.Contains(website.config.Domains, r.Host):
			path, _ := website.reader.CanonicalisePath(r.URL.Path)
			ihttp.Redirect(
				w,
				r,
				website.config.BaseURL.JoinPath(path),
				http.StatusMovedPermanently,
			)
		case re.MatchString(r.Host):
			url := website.config.BaseURL.JoinPath()
			url.Host = re.ReplaceAllString(r.Host, replace)
			ihttp.Redirect(w, r, url, http.StatusTemporaryRedirect)
		case true:
			http.NotFound(w, r)
		}
	})

	return &server.App{
		WildcardDomain: website.config.WildcardDomain,
		Domains:        website.config.Domains,
		Handler:        mux,
	}
}