package renderkit

import (
	stdhtml "html"
	"regexp"
	"strings"
	"testing"
)

var tagRe = regexp.MustCompile(`<[^>]*>`)

// visibleText strips the span markup and unescapes, i.e. what the user
// sees and what the copy button copies.
func visibleText(s string) string { return stdhtml.UnescapeString(tagRe.ReplaceAllString(s, "")) }

func TestHighlightPreservesText(t *testing.T) {
	samples := map[string]string{
		"go":   "package main\n\n// hi\nfunc main() {\n\tx := \"a<b>\" + `raw\nline`\n\tif x != nil { return 42 }\n}\n",
		"py":   "def f(x):\n    \"\"\"doc\"\"\"\n    return x # c\n",
		"bash": "echo \"$HOME\" ${A} | grep 'x' # note\nfoo#bar $#\n",
		"json": "{\"a\": [1, 2.5, true, null], \"b\": \"x\"}",
		"sql":  "SELECT count(*) FROM t WHERE a = 'x' -- c\n",
		"rust": "fn f<'a>(x: &'a str) -> u32 { 1 }\n",
		"diff": "@@ -1 +1 @@\n-old\n+new\n ctx\n",
	}
	for lang, src := range samples {
		out := highlight(lang, stdhtml.EscapeString(src))
		if got := visibleText(out); got != src {
			t.Errorf("%s: text changed\nwant %q\ngot  %q", lang, src, got)
		}
		if !strings.Contains(out, "<span class=\"tok-") {
			t.Errorf("%s: nothing was highlighted: %s", lang, out)
		}
	}
}

func TestHighlightTokens(t *testing.T) {
	out := highlight("go", stdhtml.EscapeString("func main() { return \"a<b>\" } // done"))
	for _, want := range []string{
		`<span class="tok-kw">func</span>`,
		`<span class="tok-fn">main</span>`,
		`<span class="tok-kw">return</span>`,
		`<span class="tok-str">&#34;a&lt;b&gt;&#34;</span>`,
		`<span class="tok-cmt">// done</span>`,
	} {
		if !strings.Contains(out, want) {
			t.Errorf("missing %s in %s", want, out)
		}
	}
	if !strings.Contains(highlight("json", `&#34;k&#34;: 1`), `tok-key`) {
		t.Error("json key not detected")
	}
	if !strings.Contains(highlight("sql", "select 1"), `<span class="tok-kw">select</span>`) {
		t.Error("sql keywords should be case-insensitive")
	}
}

func TestHighlightNeverInjectsMarkup(t *testing.T) {
	evil := "x := \"</span><script>alert(1)</script>\" // <img src=x onerror=1>"
	out := highlight("go", stdhtml.EscapeString(evil))
	if strings.Contains(out, "<script") || strings.Contains(out, "<img") {
		t.Fatalf("markup leaked: %s", out)
	}
}

func TestHighlightUnknownLanguageUnchanged(t *testing.T) {
	in := "a &lt; b"
	if got := highlight("brainfuck", in); got != in {
		t.Fatalf("got %q", got)
	}
	if got := highlight("", in); got != in {
		t.Fatalf("got %q", got)
	}
}

func TestMarkdownHighlightsFencedCode(t *testing.T) {
	out := Markdown("```go\nfunc main() {}\n```")
	if !strings.Contains(out, `<span class="tok-kw">func</span>`) || !strings.Contains(out, "copy-btn") {
		t.Fatalf("not highlighted: %s", out)
	}
}