package web

import (
	"strings"
	"testing"
)

const shell = `<!doctype html>
<html lang="en">
  <head>
    <title>Urpi's backlog</title>
  </head>
  <body><div id="root"></div><script type="module" src="/src/main.tsx"></script></body>
</html>`

// TestThemeLinesAreAddedWhenConfigured is the whole feature: the contract reaches
// the page.
func TestThemeLinesAreAddedWhenConfigured(t *testing.T) {
	got := string(applyThemeOrigin([]byte(shell), "https://bananas-dev.urpi.be"))

	if !strings.Contains(got, `href="https://bananas-dev.urpi.be/rt/v1/contract.css"`) {
		t.Errorf("the contract stylesheet was not added:\n%s", got)
	}
	if !strings.Contains(got, `src="https://bananas-dev.urpi.be/rt/v1/components.js"`) {
		t.Errorf("the control module was not added:\n%s", got)
	}
	// Injected before </head>, so the stylesheet is parsed before the body renders. A
	// contract that arrives late shows a flash of the fallback palette.
	headClose := strings.Index(got, "</head>")
	link := strings.Index(got, "contract.css")
	if link < 0 || link > headClose {
		t.Errorf("the contract link is not inside the head (link=%d, head=%d)", link, headClose)
	}
	// The application script must survive untouched.
	if !strings.Contains(got, `src="/src/main.tsx"`) {
		t.Error("the application script was altered")
	}
}

func TestThemeOriginTrailingSlashIsTrimmed(t *testing.T) {
	for _, base := range []string{
		"https://bananas-dev.urpi.be/",
		"https://bananas-dev.urpi.be///",
	} {
		got := string(applyThemeOrigin([]byte(shell), base))
		if strings.Contains(got, "be//") {
			t.Errorf("base %q produced a doubled slash:\n%s", base, got)
		}
	}
}

// TestNothingIsAddedWhenNoOriginIsConfigured is the branch that matters most: an
// unset or blank origin must leave the page byte-identical, because the stylesheet's
// var() fallbacks are what carry the application in that case.
func TestNothingIsAddedWhenNoOriginIsConfigured(t *testing.T) {
	for _, base := range []string{"", "   ", "\t", "/"} {
		got := applyThemeOrigin([]byte(shell), base)
		if string(got) != shell {
			t.Errorf("base %q modified the shell:\n%s", base, got)
		}
		if strings.Contains(string(got), "rt/v1") {
			t.Errorf("base %q left a contract reference behind:\n%s", base, got)
		}
	}
}

// TestShellWithoutHeadIsUnchanged covers a malformed shell. Returning the input
// unchanged is better than corrupting it, and better than a 500 on a page that would
// otherwise have rendered.
func TestShellWithoutHeadIsUnchanged(t *testing.T) {
	odd := []byte("<html><body>no head</body></html>")
	if got := applyThemeOrigin(odd, "https://bananas-dev.urpi.be"); string(got) != string(odd) {
		t.Errorf("a shell with no head was modified:\n%s", got)
	}
}