package tools

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

func writeTree(t *testing.T, root string, files map[string]string) {
	t.Helper()
	for name, content := range files {
		p := filepath.Join(root, name)
		if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(p, []byte(content), 0o644); err != nil {
			t.Fatal(err)
		}
	}
}

// TestDiscoverNestedInstructions：只发现目标子树到工作区根之间的 AGENTS.md，
// 根自己的那份跳过（它已在基础 system 提示里）。
func TestDiscoverNestedInstructions(t *testing.T) {
	root := t.TempDir()
	writeTree(t, root, map[string]string{
		"AGENTS.md":          "ROOT-RULES",
		"sub/AGENTS.md":      "SUB-RULES",
		"sub/deep/AGENTS.md": "DEEP-RULES",
		"sub/deep/x.go":      "package deep",
	})
	var got []string
	discoverInstructions(filepath.Join(root, "sub/deep/x.go"), false, root, func(p, text string) {
		got = append(got, text)
	})
	joined := strings.Join(got, ",")
	if !strings.Contains(joined, "DEEP-RULES") || !strings.Contains(joined, "SUB-RULES") {
		t.Fatalf("nested instructions not discovered: %v", got)
	}
	if strings.Contains(joined, "ROOT-RULES") {
		t.Fatalf("root AGENTS.md must be skipped: %v", got)
	}
	if len(got) != 2 || got[0] != "DEEP-RULES" || got[1] != "SUB-RULES" {
		t.Fatalf("order = %v, want nearest first", got)
	}

	// 目录目标：目录自己的 AGENTS.md 也要发现。
	got = nil
	discoverInstructions(filepath.Join(root, "sub"), true, root, func(_ string, text string) {
		got = append(got, text)
	})
	if len(got) != 1 || got[0] != "SUB-RULES" {
		t.Fatalf("directory discovery = %v", got)
	}

	// 工作区外：不发现。
	outside := t.TempDir()
	writeTree(t, outside, map[string]string{"AGENTS.md": "OUTSIDE"})
	got = nil
	discoverInstructions(filepath.Join(outside, "x.go"), false, root, func(_ string, text string) {
		got = append(got, text)
	})
	if len(got) != 0 {
		t.Fatalf("outside instructions leaked: %v", got)
	}
}

// TestReadFeedsNestedInstructions：读取子目录文件时，read 把发现的约定交给宿主钩子。
func TestReadFeedsNestedInstructions(t *testing.T) {
	root := t.TempDir()
	writeTree(t, root, map[string]string{
		"AGENTS.md":     "ROOT-RULES",
		"sub/AGENTS.md": "SUB-RULES",
		"sub/x.txt":     "hello",
	})
	var got []string
	reg := NewRegistry()
	for _, tl := range BuiltinWithHooks(root, NewFence(), nil, BuiltinHooks{
		OnInstructions: func(path, text string) { got = append(got, text) },
	}) {
		if err := reg.Register(tl); err != nil {
			t.Fatal(err)
		}
	}
	r, _ := reg.Get("read")
	if _, err := r.Run(context.Background(), `{"path":"sub/x.txt"}`); err != nil {
		t.Fatal(err)
	}
	if len(got) != 1 || got[0] != "SUB-RULES" {
		t.Fatalf("read hooks = %v", got)
	}

	// 根目录的文件不重复注入根约定。
	got = nil
	if _, err := r.Run(context.Background(), `{"path":"AGENTS.md"}`); err != nil {
		t.Fatal(err)
	}
	if len(got) != 0 {
		t.Fatalf("root instructions should not be discovered again: %v", got)
	}
}