package bootstrap

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

	"chat-agent-system/internal/config"
)

func testCfg(t *testing.T, id, dataDir, vault string) *config.Config {
	t.Helper()
	return &config.Config{InstanceID: id, DataDir: dataDir, VaultStateRoot: vault}
}

func TestEnsureInstanceCreatesMarkerAndLock(t *testing.T) {
	dir := t.TempDir()
	cfg := testCfg(t, "alpha", filepath.Join(dir, "alpha"), "")
	own, err := EnsureInstance(cfg)
	if err != nil {
		t.Fatalf("ensure: %v", err)
	}
	raw, err := os.ReadFile(filepath.Join(dir, "alpha", "instance-marker.json"))
	if err != nil {
		t.Fatalf("marker missing: %v", err)
	}
	if !strings.Contains(string(raw), "\"instance_id\": \"alpha\"") {
		t.Fatalf("marker content: %s", raw)
	}
	// 二次取得同实例：同进程内 flock 可重入（同 fd 语义），但模拟误重复
	// 启动需要另一个进程；此处验证所有权对象可用并释放。
	own.Release()
}

func TestEnsureInstanceRejectsForeignMarker(t *testing.T) {
	dir := t.TempDir()
	alpha := filepath.Join(dir, "alpha")
	if _, err := EnsureInstance(testCfg(t, "alpha", alpha, "")); err != nil {
		t.Fatal(err)
	}
	// 复用同一 data dir 但自称另一实例：必须拒绝（KTD18 不自动认领）
	if _, err := EnsureInstance(testCfg(t, "beta", alpha, "")); err == nil {
		t.Fatal("foreign instance marker must be rejected")
	}
}

func TestEnsureInstanceRejectsVaultOverlap(t *testing.T) {
	dir := t.TempDir()
	data := filepath.Join(dir, "data")
	vault := filepath.Join(data, "vault") // vault 在 data 内：非独立
	if _, err := EnsureInstance(testCfg(t, "gamma", data, vault)); err == nil {
		t.Fatal("vault inside data dir must be rejected")
	}
	vaultOut := filepath.Join(dir, "vault")
	if _, err := EnsureInstance(testCfg(t, "gamma", data, vaultOut)); err != nil {
		t.Fatalf("independent vault should pass: %v", err)
	}
}

func TestEnsureInstanceRejectsInvalidID(t *testing.T) {
	dir := t.TempDir()
	for _, bad := range []string{"", "a/b", "..", "a b", "."} {
		if _, err := EnsureInstance(testCfg(t, bad, filepath.Join(dir, "x"), "")); err == nil {
			t.Fatalf("invalid instance id %q must be rejected", bad)
		}
	}
}

func TestEnsureInstanceRejectsRootAsDataDir(t *testing.T) {
	if _, err := EnsureInstance(testCfg(t, "root-try", "/", "")); err == nil {
		t.Fatal("filesystem root as data dir must be rejected")
	}
}

func TestEnsureInstanceDetectsDuplicateStart(t *testing.T) {
	dir := t.TempDir()
	data := filepath.Join(dir, "dup")
	own, err := EnsureInstance(testCfg(t, "dup", data, ""))
	if err != nil {
		t.Fatalf("first acquire: %v", err)
	}
	defer own.Release()
	// 同机第二次取得（独立 open file description）：必须拒绝误重复启动
	if _, err := EnsureInstance(testCfg(t, "dup", data, "")); err == nil {
		t.Fatal("duplicate start must be detected and rejected")
	}
}