package main

import (
	"embed"
	"encoding/base64"
	"fmt"
	"net/http"
	"net/url"
	"strings"
)

//go:embed static/*
var StaticFiles embed.FS

func (this *Application) ServeStatic(w http.ResponseWriter, r *http.Request) {
	http.FileServer(http.FS(StaticFiles)).ServeHTTP(w, r)
	// http.StripPrefix(`/static/`, http.FileServer(http.FS(StaticFiles))).ServeHTTP(w, r)
}

func (this *Application) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if r.Method == `GET` {
		if r.URL.Path == `/` {
			this.Homepage(w, r)

		} else if r.URL.Path == `/favicon.ico` {
			w.Header().Set(`Location`, `/static/logo.png`)
			w.WriteHeader(301)

		} else if r.URL.Path == `/robots.txt` {
			http.Error(w, "not found", 404)

		} else if parts := this.rxRepoImage.FindStringSubmatch(r.URL.Path); parts != nil {
			this.Bannerpage(w, r, parts[1])

		} else if parts := this.rxRepoPage.FindStringSubmatch(r.URL.Path); parts != nil {

			// Support /repo.html URIs for backward compatibility
			if strings.HasSuffix(parts[1], `.html`) {
				w.Header().Set(`Location`, r.URL.Path[0:len(r.URL.Path)-5])
				w.WriteHeader(301)
				return
			}

			// The regexp supports an optional trailing slash
			// Redirect to canonical no-trailing-slash
			if strings.HasSuffix(r.URL.Path, `/`) {
				w.Header().Set(`Location`, `/`+parts[1]) // n.b. parts[1] isn't urldecoded yet
				w.WriteHeader(301)
				return
			}

			// Proper decoding of special characters in repo path component
			repoName, err := url.PathUnescape(parts[1])
			if err != nil {
				http.Error(w, "malformed url encoding in repository name", 400)
				return
			}

			// Maybe it's a redirected project (alternative name)
			if rename, ok := this.cfg.Redirect[repoName]; ok {
				w.Header().Set(`Location`, `/`+url.PathEscape(rename))
				w.WriteHeader(301)
				return
			}

			this.Repopage(w, r, repoName)

		} else if strings.HasPrefix(r.URL.Path, `/static/`) {

			if r.URL.Path == `/static/logo.png` && this.cfg.Template.CustomLogoPngBase64 != "" {

				logoPng, err := base64.StdEncoding.DecodeString(this.cfg.Template.CustomLogoPngBase64)
				if err != nil {
					this.internalError(w, r, fmt.Errorf("parsing base64 logo: %w", err))
					return
				}

				w.Header().Set(`Content-Length`, fmt.Sprintf("%d", len(logoPng)))
				w.Header().Set(`Content-Type`, `image/png`)
				w.WriteHeader(200)
				w.Write(logoPng)
				return
			}

			// Embedded resource
			// r.URL.Path = r.URL.Path[8:]
			this.ServeStatic(w, r)

		} else if r.URL.Query().Get("go-get") == "1" {
			// This wasn't one of our standard `/repo` paths, but there is the ?go-get=1 parameter
			// It must be a subpackage request
			// We can't serve the proper go-import meta tag immediately because
			// we haven't looked up the go.mod yet. Just redirect to the root
			// package - `go get` will follow redirects and the resulting meta tag is correct

			slashParts := strings.SplitN(r.URL.Path, `/`, 3) // len === 3 is guaranteed from earlier if cases

			w.Header().Set(`Location`, `/`+slashParts[1])
			w.WriteHeader(301)
			return

		} else {
			http.Error(w, "not found", 404)
		}

	} else {
		http.Error(w, "invalid method", 400)
	}

}