package userscript

import (
	"strings"
	"testing"
	"time"
)

// sampleScript is a stand-in for the real userscript: a metadata block with a
// @version line, the credential placeholder in its metadata and body, plus
// content that must survive the rewrites untouched.
const sampleScript = `// ==UserScript==
// @name         Manga Bookmark Sync
// @version      1.5.0
// @downloadURL  https://api.example/u/__API_TOKEN__/manga-bookmark.user.js
// @match        https://asurascans.com/*
// ==/UserScript==
(function () { "use strict";
  const API_TOKEN = "__API_TOKEN__";
})();
`

func TestStampVersionReplacesVersionLineOnly(t *testing.T) {
	mod := time.Date(2026, 7, 28, 16, 42, 0, 0, time.UTC)
	got := string(stampVersion([]byte(sampleScript), mod))

	if !strings.Contains(got, "// @version      "+mod.UTC().Format("2006.01.02.1504")) {
		t.Errorf("body has no stamped version:\n%s", got)
	}
	if strings.Contains(got, "1.5.0") {
		t.Errorf("body still carries the file's own version:\n%s", got)
	}
	// Everything outside the @version line is served verbatim, including the
	// placeholder — stamping must not do the substitution's job.
	if !strings.Contains(got, `const API_TOKEN = "__API_TOKEN__";`) {
		t.Errorf("body was altered beyond the version line:\n%s", got)
	}
}

func TestStampVersionWithoutVersionLineServedUnmodified(t *testing.T) {
	const noVersion = "// ==UserScript==\n// @name x\n// ==/UserScript==\nconsole.log(1);\n"
	if got := string(stampVersion([]byte(noVersion), time.Now())); got != noVersion {
		t.Errorf("stampVersion altered a file with no @version line:\n%s", got)
	}
}

func TestSubstituteTokenReplacesEveryPlaceholder(t *testing.T) {
	got := string(substituteToken([]byte(sampleScript), "abc123"))

	if strings.Contains(got, "__API_TOKEN__") {
		t.Errorf("placeholder survived substitution:\n%s", got)
	}
	// The credential lands in the constant and in both metadata lines.
	if want := `const API_TOKEN = "abc123";`; !strings.Contains(got, want) {
		t.Errorf("no substituted constant %q:\n%s", want, got)
	}
	if want := "https://api.example/u/abc123/manga-bookmark.user.js"; !strings.Contains(got, want) {
		t.Errorf("no substituted download URL %q:\n%s", want, got)
	}
}

func TestSubstituteTokenWithoutPlaceholderServedUnmodified(t *testing.T) {
	const noPlaceholder = "// ==UserScript==\n// @name x\n// ==/UserScript==\n"
	if got := string(substituteToken([]byte(noPlaceholder), "abc123")); got != noPlaceholder {
		t.Errorf("substituteToken altered a file without the placeholder:\n%s", got)
	}
}