package classes

import (
	"strings"
	"testing"
)

// TestSetImageAlt pins the alt rewrite: only the matching img tag is
// rewritten from its token, the alt is escaped, a missing alt is added and
// every other byte is kept (T-33-04).
func TestSetImageAlt(t *testing.T) {
	const doc = `<p class="a">x &amp; y</p><img src="https://cdn.example.test/a.jpg?x=1&amp;y=2"><img src="b.jpg" alt="old"/>`
	out, n, old := SetImageAlt(doc, "https://cdn.example.test/a.jpg?x=1&y=2", `Lion's "mane" <b>`)
	want := `<p class="a">x &amp; y</p><img src="https://cdn.example.test/a.jpg?x=1&amp;y=2" alt="Lion&#39;s &#34;mane&#34; &lt;b&gt;"><img src="b.jpg" alt="old"/>`
	if out != want || n != 1 || old != nil {
		t.Fatalf("SetImageAlt = %q, %d, %v; want %q, 1, nil", out, n, old, want)
	}
	out, n, old = SetImageAlt(doc, "b.jpg", "")
	if out != `<p class="a">x &amp; y</p><img src="https://cdn.example.test/a.jpg?x=1&amp;y=2"><img src="b.jpg" alt=""/>` || n != 1 || old == nil || *old != "old" {
		t.Fatalf("decorative = %q, %d, %v", out, n, old)
	}
	if out, n, _ := SetImageAlt(doc, "missing.jpg", "x"); out != doc || n != 0 {
		t.Fatalf("missing = %q, %d", out, n)
	}
}

// TestSetImageAltEdges pins the edges: every matching img is rewritten
// and counted (the first one's old alt answered), repeated alt attributes
// collapse to one, a src given escaped does not match the unescaped one,
// an empty src and a body without img change nothing, and text that
// looks like an img inside a comment or script is not touched.
func TestSetImageAltEdges(t *testing.T) {
	doc := `<img src="a.jpg" alt="one"><p>t</p><img alt="x" src="a.jpg" alt="y"><!-- <img src="a.jpg"> --><script>"<img src=a.jpg>"</script>`
	out, n, old := SetImageAlt(doc, "a.jpg", "new")
	if n != 2 || old == nil || *old != "one" {
		t.Fatalf("n=%d old=%v", n, old)
	}
	want := `<img src="a.jpg" alt="new"><p>t</p><img alt="new" src="a.jpg"><!-- <img src="a.jpg"> --><script>"<img src=a.jpg>"</script>`
	if out != want {
		t.Fatalf("out = %q\nwant  %q", out, want)
	}
	if out, n, _ := SetImageAlt(`<img src="a.jpg?x=1&amp;y=2">`, "a.jpg?x=1&amp;y=2", "z"); n != 0 || out != `<img src="a.jpg?x=1&amp;y=2">` {
		t.Fatalf("escaped src matched: %q %d", out, n)
	}
	for _, tc := range []struct{ html, src string }{{`<img src="a.jpg">`, ""}, {`<p>no images</p>`, "a.jpg"}, {"", "a.jpg"}} {
		if out, n, old := SetImageAlt(tc.html, tc.src, "x"); out != tc.html || n != 0 || old != nil {
			t.Errorf("SetImageAlt(%q, %q) = %q %d %v", tc.html, tc.src, out, n, old)
		}
	}
	// L1 WR-03: the bytes of an unfinished tag at the end are kept.
	for _, in := range []string{"p a <img", "x<y", `<img src="b.jpg"><p>a <b`} {
		if out, n, _ := SetImageAlt(in, "a.jpg", "z"); out != in || n != 0 {
			t.Errorf("SetImageAlt(%q) = %q %d", in, out, n)
		}
	}
	if out, n, _ := SetImageAlt(`<img src="a.jpg"><p>a <b`, "a.jpg", "z"); out != `<img src="a.jpg" alt="z"><p>a <b` || n != 1 {
		t.Errorf("match with an unfinished tail = %q %d", out, n)
	}
}

// TestSetMarkdownImageAlt pins P33-65 (L1 WR-05): inline images with or
// without a title get the alt; a destination written unescaped matches the
// src goldmark renders for it; an alt with ] and a line break is escaped
// and folded; the same image in a fence or a code span is left alone; a
// reference-style image is not matched.
func TestSetMarkdownImageAlt(t *testing.T) {
	out, n, old := SetMarkdownImageAlt("A ![](/a.jpg) and ![old](/a.jpg \"t\") and ![x](/b.jpg).", "/a.jpg", "Lion's mane")
	if n != 2 || old == nil || *old != "" || out != "A ![Lion's mane](/a.jpg) and ![Lion's mane](/a.jpg \"t\") and ![x](/b.jpg)." {
		t.Fatalf("plain = %q %d %v", out, n, old)
	}
	html, err := FormatHTML("![x](</a b.jpg>)")
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(html, `src="/a%20b.jpg"`) {
		t.Fatalf("goldmark src = %s", html)
	}
	if out, n, _ := SetMarkdownImageAlt("![x](</a b.jpg>)", "/a%20b.jpg", "y"); n != 1 || out != "![y](</a b.jpg>)" {
		t.Fatalf("escaped src = %q %d", out, n)
	}
	if out, n, _ := SetMarkdownImageAlt("![x](/ż.jpg)", "/%C5%BC.jpg", "y"); n != 1 || out != "![y](/ż.jpg)" {
		t.Fatalf("non-ASCII src = %q %d", out, n)
	}
	if out, _, _ := SetMarkdownImageAlt("![x](/a.jpg)", "/a.jpg", "a ] b\nc [d] \\e"); out != `![a \] b c \[d\] \\e](/a.jpg)` {
		t.Fatalf("escaped alt = %q", out)
	}
	code := "```\n![x](/a.jpg)\n```\n\nInline `![x](/a.jpg)` and\n\n    ![x](/a.jpg)\n"
	if out, n, _ := SetMarkdownImageAlt(code, "/a.jpg", "y"); n != 0 || out != code {
		t.Fatalf("code = %q %d", out, n)
	}
	ref := "![x][a]\n\n[a]: /a.jpg\n"
	if out, n, _ := SetMarkdownImageAlt(ref, "/a.jpg", "y"); n != 0 || out != ref {
		t.Fatalf("reference = %q %d", out, n)
	}
	// The rendered alt follows the markdown.
	out, _, _ = SetMarkdownImageAlt("Text\n\n![](/a.jpg)\n", "/a.jpg", "Grzyb [leśny]")
	if html, _ := FormatHTML(out); !strings.Contains(html, `alt="Grzyb [leśny]"`) {
		t.Fatalf("rendered = %s", html)
	}

	// SetImageAltOutsideCode: a raw img gets the alt, one in a code sample
	// keeps its bytes.
	raw := "<img src=\"/a.jpg\">\n\n```html\n<img src=\"/a.jpg\">\n```\n\nand `<img src=\"/a.jpg\">`\n"
	got, n, _ := SetImageAltOutsideCode(raw, "/a.jpg", "z")
	want := "<img src=\"/a.jpg\" alt=\"z\">\n\n```html\n<img src=\"/a.jpg\">\n```\n\nand `<img src=\"/a.jpg\">`\n"
	if n != 1 || got != want {
		t.Fatalf("outside code = %q %d", got, n)
	}
}