package main

import (
	"bytes"
	"compress/gzip"
	"io"
	"io/fs"
	"net/http"
	"net/http/httptest"
	"regexp"
	"strings"
	"testing"
)

// Every {{asset "…"}} in the templates must name an embedded file, or the page
// fails to render.
func TestTemplateAssetsExist(t *testing.T) {
	ref := regexp.MustCompile(`\{\{asset "([^"]+)"\}\}`)
	_ = fs.WalkDir(assets, "assets", func(p string, d fs.DirEntry, err error) error {
		if err != nil || d.IsDir() {
			return err
		}
		b, _ := assets.ReadFile(p)
		for _, m := range ref.FindAllSubmatch(b, -1) {
			if _, err := assetURL(string(m[1])); err != nil {
				t.Errorf("%s: %v", p, err)
			}
		}
		return nil
	})
}

func TestServeStaticCaching(t *testing.T) {
	h := serveStatic()
	get := func(url, ifNoneMatch string) *httptest.ResponseRecorder {
		r := httptest.NewRequest(http.MethodGet, url, nil)
		if ifNoneMatch != "" {
			r.Header.Set("If-None-Match", ifNoneMatch)
		}
		w := httptest.NewRecorder()
		h.ServeHTTP(w, r)
		return w
	}
	v := assetVersions["style.css"]

	versioned, _ := assetURL("style.css")
	if w := get(versioned, ""); w.Code != 200 || w.Header().Get("Cache-Control") != "public, max-age=31536000, immutable" {
		t.Errorf("versioned: %d %q", w.Code, w.Header().Get("Cache-Control"))
	}
	for _, u := range []string{"/_/style.css", "/_/style.css?v=stale"} {
		w := get(u, "")
		if w.Code != 200 || w.Header().Get("Cache-Control") != "no-cache" || w.Header().Get("ETag") != `"`+v+`"` {
			t.Errorf("%s: %d %q %q", u, w.Code, w.Header().Get("Cache-Control"), w.Header().Get("ETag"))
		}
	}
	if w := get("/_/style.css", `"`+v+`"`); w.Code != http.StatusNotModified {
		t.Errorf("revalidate: got %d, want 304", w.Code)
	}
	if w := get("/_/fonts/IosevkaSlab.woff2", ""); w.Header().Get("Cache-Control") != "public, max-age=31536000, immutable" {
		t.Errorf("font: %q", w.Header().Get("Cache-Control"))
	}
}

func TestServeStaticGzip(t *testing.T) {
	h := serveStatic()
	get := func(url, acceptEncoding, ifNoneMatch string) *httptest.ResponseRecorder {
		r := httptest.NewRequest(http.MethodGet, url, nil)
		if acceptEncoding != "" {
			r.Header.Set("Accept-Encoding", acceptEncoding)
		}
		if ifNoneMatch != "" {
			r.Header.Set("If-None-Match", ifNoneMatch)
		}
		w := httptest.NewRecorder()
		h.ServeHTTP(w, r)
		return w
	}
	want, _ := assets.ReadFile("assets/style.css")

	w := get("/_/style.css", "gzip, deflate, br", "")
	if w.Code != 200 || w.Header().Get("Content-Encoding") != "gzip" || w.Header().Get("Vary") != "Accept-Encoding" {
		t.Fatalf("gzip: %d %q %q", w.Code, w.Header().Get("Content-Encoding"), w.Header().Get("Vary"))
	}
	if ct := w.Header().Get("Content-Type"); !strings.HasPrefix(ct, "text/css") {
		t.Errorf("content-type: %q", ct)
	}
	zr, err := gzip.NewReader(w.Body)
	if err != nil {
		t.Fatal(err)
	}
	got, _ := io.ReadAll(zr)
	if !bytes.Equal(got, want) {
		t.Errorf("gzip body does not decompress to style.css")
	}

	etag := w.Header().Get("ETag")
	if w := get("/_/style.css", "gzip", etag); w.Code != http.StatusNotModified {
		t.Errorf("gzip revalidate: got %d, want 304", w.Code)
	}

	for _, ae := range []string{"", "identity", "gzip;q=0"} {
		w := get("/_/style.css", ae, "")
		if w.Header().Get("Content-Encoding") != "" || !bytes.Equal(w.Body.Bytes(), want) {
			t.Errorf("Accept-Encoding %q: got encoding %q", ae, w.Header().Get("Content-Encoding"))
		}
	}

	if w := get("/_/fonts/IosevkaSlab.woff2", "gzip", ""); w.Header().Get("Content-Encoding") != "" {
		t.Errorf("font should not be re-compressed")
	}
}