package devicehistory

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

	"github.com/yuanyuanxiang/SimpleRemoter/server/go/connection"
	"github.com/yuanyuanxiang/SimpleRemoter/server/go/hub"
)

func testDevice(id, name string) hub.DeviceInfo {
	return hub.DeviceInfo{
		ID:      id,
		Name:    name,
		Group:   "office",
		Version: "1.2.3",
		OS:      "Windows 11",
		IP:      "203.0.113.7",
		PeerIP:  "198.51.100.9",
		Screen:  "1:1920*1080",
		Online:  true,
	}
}

func TestStoreRecordsLifecycleViaHub(t *testing.T) {
	path := filepath.Join(t.TempDir(), "devices.json")
	s, err := Open(path, 1000, nil)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	t.Cleanup(func() { _ = s.Close() })

	h := hub.New()
	h.Subscribe(s)

	h.Register(&hub.Device{ID: "dev-1", Name: "PC-1", Group: "office"},
		&connection.Context{RemoteAddr: "198.51.100.9:5000"})

	// The device is online, so it must not appear in the offline list.
	if got := s.Offline(map[string]struct{}{"dev-1": {}}); len(got) != 0 {
		t.Fatalf("offline while online = %d, want 0", len(got))
	}

	h.Unregister("dev-1")

	off := s.Offline(nil)
	if len(off) != 1 {
		t.Fatalf("offline entries = %d, want 1", len(off))
	}
	d := off[0]
	if d.ID != "dev-1" || d.Name != "PC-1" || d.Group != "office" {
		t.Fatalf("offline device = %+v", d)
	}
	if d.Online {
		t.Fatal("offline entry marked online")
	}
	if d.LastSeen == 0 {
		t.Fatal("last_seen not set")
	}
}

func TestStorePersistsAndPreservesFirstSeen(t *testing.T) {
	path := filepath.Join(t.TempDir(), "devices.json")
	s, err := Open(path, 1000, nil)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}

	first := time.Unix(1_700_000_000, 0)
	s.upsertAt(testDevice("dev-1", "old-name"), first)
	// A later login refreshes display fields and last_seen but keeps first_seen.
	s.upsertAt(testDevice("dev-1", "new-name"), first.Add(time.Hour))
	if err := s.Flush(); err != nil {
		t.Fatalf("Flush: %v", err)
	}
	_ = s.Close()

	reopened, err := Open(path, 1000, nil)
	if err != nil {
		t.Fatalf("reopen: %v", err)
	}
	t.Cleanup(func() { _ = reopened.Close() })

	reopened.mu.Lock()
	rec := reopened.devices["dev-1"]
	reopened.mu.Unlock()
	if rec == nil {
		t.Fatal("record not persisted")
	}
	if rec.Name != "new-name" {
		t.Fatalf("name = %q, want new-name", rec.Name)
	}
	if rec.FirstSeen != first.Unix() {
		t.Fatalf("first_seen = %d, want %d", rec.FirstSeen, first.Unix())
	}
	if rec.LastSeen != first.Add(time.Hour).Unix() {
		t.Fatalf("last_seen = %d, want %d", rec.LastSeen, first.Add(time.Hour).Unix())
	}
}

func TestStorePrunesOldest(t *testing.T) {
	path := filepath.Join(t.TempDir(), "devices.json")
	s, err := Open(path, 2, nil)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	t.Cleanup(func() { _ = s.Close() })

	base := time.Unix(1_700_000_000, 0)
	s.upsertAt(testDevice("a", "A"), base)
	s.upsertAt(testDevice("b", "B"), base.Add(time.Minute))
	s.upsertAt(testDevice("c", "C"), base.Add(2*time.Minute))

	s.mu.Lock()
	_, hasA := s.devices["a"]
	_, hasC := s.devices["c"]
	n := len(s.devices)
	s.mu.Unlock()
	if n != 2 || hasA || !hasC {
		t.Fatalf("after prune: n=%d hasA=%v hasC=%v, want 2/false/true", n, hasA, hasC)
	}
}

func TestPruneEvictsOfflineBeforeOnline(t *testing.T) {
	path := filepath.Join(t.TempDir(), "devices.json")
	s, err := Open(path, 2, nil)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	t.Cleanup(func() { _ = s.Close() })

	base := time.Unix(1_700_000_000, 0)
	s.upsertAt(testDevice("online-old", "Old"), base)
	s.upsertAt(testDevice("offline-new", "Gone"), base.Add(time.Minute))
	s.offlineAt("offline-new", base.Add(2*time.Minute))
	// This upsert exceeds the cap; the offline record must be evicted before
	// the still-connected device, even though its last_seen is newer.
	s.upsertAt(testDevice("online-2", "New"), base.Add(3*time.Minute))

	s.mu.Lock()
	_, hasOld := s.devices["online-old"]
	_, hasGone := s.devices["offline-new"]
	_, hasNew := s.devices["online-2"]
	n := len(s.devices)
	s.mu.Unlock()
	if n != 2 || !hasOld || hasGone || !hasNew {
		t.Fatalf("after prune: n=%d hasOld=%v hasGone=%v hasNew=%v", n, hasOld, hasGone, hasNew)
	}
}

func TestStoreOfflineSortedNewestFirst(t *testing.T) {
	path := filepath.Join(t.TempDir(), "devices.json")
	s, err := Open(path, 1000, nil)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	t.Cleanup(func() { _ = s.Close() })

	base := time.Unix(1_700_000_000, 0)
	s.upsertAt(testDevice("old", "Old"), base)
	s.upsertAt(testDevice("new", "New"), base.Add(time.Hour))

	off := s.Offline(nil)
	if len(off) != 2 || off[0].ID != "new" || off[1].ID != "old" {
		t.Fatalf("offline order = %+v, want new then old", off)
	}
}

func TestOpenCorruptFileStartsEmptyAndRecovers(t *testing.T) {
	path := filepath.Join(t.TempDir(), "devices.json")
	if err := os.WriteFile(path, []byte("{not json"), 0o644); err != nil {
		t.Fatal(err)
	}

	s, err := Open(path, 1000, nil)
	if err == nil {
		t.Fatal("Open corrupt file: want error, got nil")
	}
	if len(s.devices) != 0 {
		t.Fatalf("corrupt load produced %d records, want 0", len(s.devices))
	}
	t.Cleanup(func() { _ = s.Close() })

	s.upsertAt(testDevice("dev-1", "PC-1"), time.Unix(1_700_000_000, 0))
	if err := s.Flush(); err != nil {
		t.Fatalf("Flush after corrupt load: %v", err)
	}

	reopened, err := Open(path, 1000, nil)
	if err != nil {
		t.Fatalf("reopen: %v", err)
	}
	t.Cleanup(func() { _ = reopened.Close() })
	if len(reopened.devices) != 1 {
		t.Fatalf("records after recovery = %d, want 1", len(reopened.devices))
	}
}

func TestStoreRemovePersistsDeletion(t *testing.T) {
	path := filepath.Join(t.TempDir(), "devices.json")
	s, err := Open(path, 1000, nil)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}

	base := time.Unix(1_700_000_000, 0)
	s.upsertAt(testDevice("gone", "Gone"), base)
	s.upsertAt(testDevice("kept", "Kept"), base.Add(time.Minute))

	if !s.Remove("gone") {
		t.Fatal("Remove existing record = false, want true")
	}
	if s.Remove("gone") {
		t.Fatal("Remove missing record = true, want false")
	}
	if got := s.Offline(nil); len(got) != 1 || got[0].ID != "kept" {
		t.Fatalf("offline after remove = %+v, want only kept", got)
	}
	if err := s.Flush(); err != nil {
		t.Fatalf("Flush: %v", err)
	}
	_ = s.Close()

	reopened, err := Open(path, 1000, nil)
	if err != nil {
		t.Fatalf("reopen: %v", err)
	}
	t.Cleanup(func() { _ = reopened.Close() })
	if _, ok := reopened.devices["gone"]; ok {
		t.Fatal("removed record came back after reload")
	}
	if _, ok := reopened.devices["kept"]; !ok {
		t.Fatal("kept record missing after reload")
	}
}

func TestFlushLeavesNoTempFiles(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "devices.json")
	s, err := Open(path, 1000, nil)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	t.Cleanup(func() { _ = s.Close() })

	s.upsertAt(testDevice("dev-1", "PC-1"), time.Unix(1_700_000_000, 0))
	if err := s.Flush(); err != nil {
		t.Fatalf("Flush: %v", err)
	}

	entries, err := os.ReadDir(dir)
	if err != nil {
		t.Fatal(err)
	}
	for _, e := range entries {
		if strings.HasSuffix(e.Name(), ".tmp") {
			t.Fatalf("leftover temp file: %s", e.Name())
		}
	}
}