package skill

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func writeSkill(t *testing.T, root, dirName, frontmatter, body string) {
	t.Helper()
	dir := filepath.Join(root, dirName)
	if err := os.MkdirAll(dir, 0o755); err != nil {
		t.Fatal(err)
	}
	content := "---\n" + frontmatter + "---\n\n" + body
	if err := os.WriteFile(filepath.Join(dir, "SKILL.md"), []byte(content), 0o644); err != nil {
		t.Fatal(err)
	}
}

func TestDiscover_ParsesFrontmatterAndBody(t *testing.T) {
	root := t.TempDir()
	writeSkill(t, root, "refactoring",
		"name: refactoring\ndescription: Vorgehen für größere Refactorings.\n",
		"# Refactoring\n\nSchritt 1: Tests lesen.\n")

	skills, err := Discover([]string{root})
	if err != nil {
		t.Fatal(err)
	}
	if len(skills) != 1 {
		t.Fatalf("got %d skills, want 1", len(skills))
	}
	s := skills[0]
	if s.Name != "refactoring" {
		t.Errorf("name = %q", s.Name)
	}
	if s.Description != "Vorgehen für größere Refactorings." {
		t.Errorf("description = %q", s.Description)
	}
	if !strings.Contains(s.Body, "Schritt 1: Tests lesen.") {
		t.Errorf("body missing expected content: %q", s.Body)
	}
	if strings.Contains(s.Body, "---") {
		t.Errorf("body should not contain frontmatter delimiters: %q", s.Body)
	}
}

func TestDiscover_LaterPathOverridesEarlierByName(t *testing.T) {
	global := t.TempDir()
	project := t.TempDir()
	writeSkill(t, global, "refactoring", "name: refactoring\ndescription: global version\n", "global body")
	writeSkill(t, project, "refactoring", "name: refactoring\ndescription: project version\n", "project body")

	skills, err := Discover([]string{global, project})
	if err != nil {
		t.Fatal(err)
	}
	if len(skills) != 1 {
		t.Fatalf("got %d skills, want 1 (deduped by name)", len(skills))
	}
	if skills[0].Description != "project version" {
		t.Errorf("description = %q, want project version to win (later path)", skills[0].Description)
	}
}

func TestDiscover_MissingPathIsSkippedNotError(t *testing.T) {
	skills, err := Discover([]string{"/does/not/exist/at/all"})
	if err != nil {
		t.Fatal(err)
	}
	if len(skills) != 0 {
		t.Errorf("got %d skills, want 0", len(skills))
	}
}

// TestRenderIndex_OmitsBody ist das M5-Fertig-Kriterium aus Abschnitt 6: ein
// Skill wird erst bei Bedarf geladen — der Index darf nur Name+Description
// enthalten, ein Token-Delta zum vollen Body muss messbar sein.
func TestRenderIndex_OmitsBody(t *testing.T) {
	root := t.TempDir()
	longBody := strings.Repeat("Dies ist eine lange Anleitung. ", 200) // ~1400 Zeichen
	writeSkill(t, root, "refactoring", "name: refactoring\ndescription: kurze Beschreibung\n", longBody)

	skills, err := Discover([]string{root})
	if err != nil {
		t.Fatal(err)
	}

	index := RenderIndex(skills)
	if strings.Contains(index, longBody) {
		t.Fatal("index must not contain the full skill body")
	}
	if !strings.Contains(index, "refactoring") || !strings.Contains(index, "kurze Beschreibung") {
		t.Errorf("index missing name/description: %q", index)
	}
	if len(index) >= len(longBody) {
		t.Errorf("index (%d bytes) should be far smaller than the body (%d bytes)", len(index), len(longBody))
	}
}