package middleware_test

import (
	"context"
	"crypto/sha256"
	"encoding/base64"
	"regexp"
	"strings"
	"testing"

	"bookhoard/internal/middleware"
	"bookhoard/templates"
)

// TestThemeFlashGuardHashMatchesCSP pins the CSP script hash to the theme
// flash guard's rendered bytes: the guard is the app's ONLY inline script,
// and script-src allow-lists it by content hash. If the guard's script text
// is ever edited, this test fails and prints the replacement hash — copy it
// into middleware.ScriptHashThemeFlashGuard.
func TestThemeFlashGuardHashMatchesCSP(t *testing.T) {
	var sb strings.Builder
	if err := templates.ThemeFlashGuard().Render(context.Background(), &sb); err != nil {
		t.Fatalf("render ThemeFlashGuard: %v", err)
	}
	rendered := sb.String()

	m := regexp.MustCompile(`(?s)<script>(.*?)</script>`).FindStringSubmatch(rendered)
	if m == nil {
		t.Fatalf("rendered guard contains no <script> element:\n%s", rendered)
	}
	digest := sha256.Sum256([]byte(m[1]))
	computed := "sha256-" + base64.StdEncoding.EncodeToString(digest[:])
	if !strings.Contains(middleware.ScriptHashThemeFlashGuard, computed) {
		t.Errorf(`
theme flash guard script hash drifted.

  CSP constant contains:    %s
  rendered script hashes to: %s

Recompute: sha256 over the bytes between <script> and </script> of
templates/theme_flash_guard.templ, base64-encoded, then update
middleware.ScriptHashThemeFlashGuard and the CSP header string.`,
			middleware.ScriptHashThemeFlashGuard, computed)
	}

	// The strict allow-list only holds the guard: no 'unsafe-inline' may
	// sneak back into script-src (style-src keeps it for htmx/Alpine).
	if strings.Contains(middleware.ScriptHashThemeFlashGuard, "unsafe-inline") {
		t.Error("script-src must not re-introduce 'unsafe-inline' alongside the hash")
	}
}