package api_test

import (
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"visiona-local/server/internal/api"
	"visiona-local/server/internal/api/handlers"
	"visiona-local/server/internal/api/ws"
	"visiona-local/server/internal/camera"
	"visiona-local/server/internal/device"
	"visiona-local/server/internal/inference"
	"visiona-local/server/internal/model"
	"visiona-local/server/pkg/logger"
)

// apiResponse is the standard JSON envelope for all API responses.
type apiResponse struct {
	Success bool            `json:"success"`
	Data    json.RawMessage `json:"data,omitempty"`
	Error   *struct {
		Code    string `json:"code"`
		Message string `json:"message"`
	} `json:"error,omitempty"`
}

// setupTestServer creates a fully wired Gin router with mock devices.
func setupTestServer(t *testing.T, mockCount int) *httptest.Server {
	t.Helper()

	registry := device.NewRegistry()
	deviceMgr := device.NewManager(registry, true, mockCount, "")
	// Drain event bus to prevent blocking
	go func() {
		for range deviceMgr.Events() {
		}
	}()

	modelRepo := model.NewRepository("")
	modelStore := model.NewModelStore(t.TempDir())
	cameraMgr := camera.NewManager(true)
	inferenceSvc := inference.NewService(deviceMgr)
	wsHub := ws.NewHub()
	logBroadcaster := logger.NewBroadcaster(100, nil)
	sysHandler := handlers.NewSystemHandler("test", "now", nil)

	router := api.NewRouter(
		modelRepo, modelStore, deviceMgr, cameraMgr,
		inferenceSvc, wsHub, nil, logBroadcaster, sysHandler,
	)

	return httptest.NewServer(router)
}

func getJSON(t *testing.T, ts *httptest.Server, path string) apiResponse {
	t.Helper()
	resp, err := http.Get(ts.URL + path)
	if err != nil {
		t.Fatalf("GET %s: %v", path, err)
	}
	defer resp.Body.Close()
	var r apiResponse
	if err := json.NewDecoder(resp.Body).Decode(&r); err != nil {
		t.Fatalf("GET %s: decode error: %v", path, err)
	}
	return r
}

func postJSON(t *testing.T, ts *httptest.Server, path string, body string) apiResponse {
	t.Helper()
	resp, err := http.Post(ts.URL+path, "application/json", strings.NewReader(body))
	if err != nil {
		t.Fatalf("POST %s: %v", path, err)
	}
	defer resp.Body.Close()
	var r apiResponse
	if err := json.NewDecoder(resp.Body).Decode(&r); err != nil {
		t.Fatalf("POST %s: decode error: %v", path, err)
	}
	return r
}

// ---------------------------------------------------------------------------
// Tests
// ---------------------------------------------------------------------------

func TestHealthCheck(t *testing.T) {
	ts := setupTestServer(t, 0)
	defer ts.Close()

	resp, err := http.Get(ts.URL + "/api/system/health")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != 200 {
		t.Fatalf("health check status = %d, want 200", resp.StatusCode)
	}
	var data map[string]string
	json.NewDecoder(resp.Body).Decode(&data)
	if data["status"] != "ok" {
		t.Fatalf("health check status = %q, want 'ok'", data["status"])
	}
}

func TestDeviceWorkflow_MockMode(t *testing.T) {
	ts := setupTestServer(t, 2)
	defer ts.Close()

	// 1. List devices — should have 2 mock devices
	t.Run("list devices", func(t *testing.T) {
		r := getJSON(t, ts, "/api/devices")
		if !r.Success {
			t.Fatal("list devices should succeed")
		}
		var data struct {
			Devices []json.RawMessage `json:"devices"`
		}
		json.Unmarshal(r.Data, &data)
		if len(data.Devices) != 2 {
			t.Fatalf("expected 2 devices, got %d", len(data.Devices))
		}
	})

	// 2. Get single device
	t.Run("get device", func(t *testing.T) {
		r := getJSON(t, ts, "/api/devices/mock-device-1")
		if !r.Success {
			t.Fatal("get device should succeed")
		}
	})

	// 3. Get non-existing device → 404
	t.Run("get device not found", func(t *testing.T) {
		r := getJSON(t, ts, "/api/devices/nonexistent")
		if r.Success {
			t.Fatal("should fail for non-existing device")
		}
		if r.Error == nil || r.Error.Code != "DEVICE_NOT_FOUND" {
			t.Fatalf("expected DEVICE_NOT_FOUND error, got %+v", r.Error)
		}
	})

	// 4. Connect device
	t.Run("connect device", func(t *testing.T) {
		r := postJSON(t, ts, "/api/devices/mock-device-1/connect", "")
		if !r.Success {
			t.Fatalf("connect should succeed: %+v", r.Error)
		}

		// Verify status changed to connected
		r2 := getJSON(t, ts, "/api/devices/mock-device-1")
		var info struct {
			Status string `json:"status"`
		}
		json.Unmarshal(r2.Data, &info)
		if info.Status != "connected" {
			t.Fatalf("expected status 'connected', got '%s'", info.Status)
		}
	})

	// 5. Start inference
	t.Run("start inference", func(t *testing.T) {
		r := postJSON(t, ts, "/api/devices/mock-device-1/inference/start", "")
		if !r.Success {
			t.Fatalf("start inference should succeed: %+v", r.Error)
		}
	})

	// 6. Stop inference
	t.Run("stop inference", func(t *testing.T) {
		r := postJSON(t, ts, "/api/devices/mock-device-1/inference/stop", "")
		if !r.Success {
			t.Fatalf("stop inference should succeed: %+v", r.Error)
		}
	})

	// 7. Disconnect device
	t.Run("disconnect device", func(t *testing.T) {
		r := postJSON(t, ts, "/api/devices/mock-device-1/disconnect", "")
		if !r.Success {
			t.Fatalf("disconnect should succeed: %+v", r.Error)
		}
	})
}

func TestDeviceScan_MockMode(t *testing.T) {
	ts := setupTestServer(t, 1)
	defer ts.Close()

	// In mock mode, scan just returns existing mock devices
	r := postJSON(t, ts, "/api/devices/scan", "")
	if !r.Success {
		t.Fatalf("scan should succeed: %+v", r.Error)
	}
	var data struct {
		Devices []json.RawMessage `json:"devices"`
	}
	json.Unmarshal(r.Data, &data)
	if len(data.Devices) != 1 {
		t.Fatalf("expected 1 device after scan, got %d", len(data.Devices))
	}
}

func TestModelList(t *testing.T) {
	ts := setupTestServer(t, 0)
	defer ts.Close()

	r := getJSON(t, ts, "/api/models")
	if !r.Success {
		t.Fatal("list models should succeed")
	}
}

func TestConnectNonExistentDevice(t *testing.T) {
	ts := setupTestServer(t, 1)
	defer ts.Close()

	r := postJSON(t, ts, "/api/devices/nonexistent/connect", "")
	if r.Success {
		t.Fatal("connect nonexistent device should fail")
	}
}

func TestMultiDeviceIsolation(t *testing.T) {
	ts := setupTestServer(t, 3)
	defer ts.Close()

	// Connect device 1 only
	r := postJSON(t, ts, "/api/devices/mock-device-1/connect", "")
	if !r.Success {
		t.Fatalf("connect device 1 should succeed: %+v", r.Error)
	}

	// Device 2 should still be detected (not connected)
	r2 := getJSON(t, ts, "/api/devices/mock-device-2")
	var info struct {
		Status string `json:"status"`
	}
	json.Unmarshal(r2.Data, &info)
	if info.Status != "detected" {
		t.Fatalf("device 2 should be 'detected', got '%s'", info.Status)
	}
}