package handlers

import (
	"bytes"
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/go-chi/chi/v5"
	"github.com/orchard9/rdev/internal/domain"
	"github.com/orchard9/rdev/internal/service"
)

// mockWorkQueue implements port.WorkQueue for testing.
type mockWorkQueue struct {
	tasks map[string]*domain.WorkTask
	err   error
}

func newMockWorkQueue() *mockWorkQueue {
	return &mockWorkQueue{
		tasks: make(map[string]*domain.WorkTask),
	}
}

func (m *mockWorkQueue) Enqueue(ctx context.Context, task *domain.WorkTask) (string, error) {
	if m.err != nil {
		return "", m.err
	}
	id := "task-123"
	task.ID = id
	task.Status = domain.WorkTaskStatusPending
	task.CreatedAt = time.Now()
	m.tasks[id] = task
	return id, nil
}

func (m *mockWorkQueue) Dequeue(ctx context.Context, workerID string) (*domain.WorkTask, error) {
	if m.err != nil {
		return nil, m.err
	}
	for _, task := range m.tasks {
		if task.Status == domain.WorkTaskStatusPending {
			task.Status = domain.WorkTaskStatusRunning
			task.WorkerID = workerID
			now := time.Now()
			task.StartedAt = &now
			return task, nil
		}
	}
	return nil, nil
}

func (m *mockWorkQueue) Complete(ctx context.Context, taskID string, result *domain.WorkResult) error {
	if m.err != nil {
		return m.err
	}
	task, ok := m.tasks[taskID]
	if !ok {
		return domain.ErrWorkTaskNotFound
	}
	task.Status = domain.WorkTaskStatusCompleted
	task.Result = result
	now := time.Now()
	task.CompletedAt = &now
	return nil
}

func (m *mockWorkQueue) Fail(ctx context.Context, taskID string, errMsg string) error {
	if m.err != nil {
		return m.err
	}
	task, ok := m.tasks[taskID]
	if !ok {
		return domain.ErrWorkTaskNotFound
	}
	if task.RetryCount < task.MaxRetries {
		task.Status = domain.WorkTaskStatusPending
		task.RetryCount++
		task.Error = errMsg
	} else {
		task.Status = domain.WorkTaskStatusFailed
		task.Error = errMsg
		now := time.Now()
		task.CompletedAt = &now
	}
	return nil
}

func (m *mockWorkQueue) Cancel(ctx context.Context, taskID string) error {
	if m.err != nil {
		return m.err
	}
	task, ok := m.tasks[taskID]
	if !ok {
		return domain.ErrWorkTaskNotFound
	}
	if task.Status != domain.WorkTaskStatusPending {
		return domain.ErrWorkTaskNotFound
	}
	task.Status = domain.WorkTaskStatusCancelled
	now := time.Now()
	task.CompletedAt = &now
	return nil
}

func (m *mockWorkQueue) GetTask(ctx context.Context, taskID string) (*domain.WorkTask, error) {
	if m.err != nil {
		return nil, m.err
	}
	task, ok := m.tasks[taskID]
	if !ok {
		return nil, domain.ErrWorkTaskNotFound
	}
	return task, nil
}

func (m *mockWorkQueue) ListByProject(ctx context.Context, projectID string, status *domain.WorkTaskStatus, opts domain.WorkListOptions) (*domain.WorkListResult, error) {
	if m.err != nil {
		return nil, m.err
	}
	opts.Normalize()

	var tasks []*domain.WorkTask
	for _, task := range m.tasks {
		if task.ProjectID == projectID {
			if status == nil || task.Status == *status {
				tasks = append(tasks, task)
			}
		}
	}

	// Apply pagination
	total := int64(len(tasks))
	if opts.Offset >= len(tasks) {
		tasks = nil
	} else {
		end := opts.Offset + opts.Limit
		if end > len(tasks) {
			end = len(tasks)
		}
		tasks = tasks[opts.Offset:end]
	}

	return &domain.WorkListResult{
		Tasks:  tasks,
		Total:  total,
		Limit:  opts.Limit,
		Offset: opts.Offset,
	}, nil
}

func (m *mockWorkQueue) GetStats(ctx context.Context) (*domain.WorkQueueStats, error) {
	if m.err != nil {
		return nil, m.err
	}
	stats := &domain.WorkQueueStats{}
	for _, task := range m.tasks {
		switch task.Status {
		case domain.WorkTaskStatusPending:
			stats.Pending++
		case domain.WorkTaskStatusRunning:
			stats.Running++
		case domain.WorkTaskStatusCompleted:
			stats.Completed++
		case domain.WorkTaskStatusFailed:
			stats.Failed++
		case domain.WorkTaskStatusCancelled:
			stats.Cancelled++
		}
	}
	return stats, nil
}

func (m *mockWorkQueue) CleanupOld(ctx context.Context, olderThan time.Duration) (int64, error) {
	return 0, m.err
}

func (m *mockWorkQueue) RequeueStale(ctx context.Context, timeout time.Duration) (int64, error) {
	return 0, m.err
}

func TestWorkHandler_Enqueue(t *testing.T) {
	mockQueue := newMockWorkQueue()
	workService := service.NewWorkService(mockQueue, service.WorkServiceConfig{})
	handler := NewWorkHandler(workService)

	router := chi.NewRouter()
	handler.Mount(router)

	tests := []struct {
		name       string
		body       EnqueueWorkRequest
		wantStatus int
	}{
		{
			name: "valid_build_task",
			body: EnqueueWorkRequest{
				ProjectID: "test-project",
				TaskType:  "build",
				Spec: map[string]any{
					"prompt":   "Build a landing page",
					"template": "nextjs-landing",
				},
			},
			wantStatus: http.StatusCreated,
		},
		{
			name: "valid_test_task",
			body: EnqueueWorkRequest{
				ProjectID: "test-project",
				TaskType:  "test",
				Spec: map[string]any{
					"test_command": "npm test",
				},
			},
			wantStatus: http.StatusCreated,
		},
		{
			name: "valid_deploy_task",
			body: EnqueueWorkRequest{
				ProjectID: "test-project",
				TaskType:  "deploy",
				Spec: map[string]any{
					"image":    "registry.example.com/app:latest",
					"replicas": 2,
				},
			},
			wantStatus: http.StatusCreated,
		},
		{
			name: "valid_custom_task",
			body: EnqueueWorkRequest{
				ProjectID: "test-project",
				TaskType:  "custom",
				Spec: map[string]any{
					"action": "cleanup",
				},
			},
			wantStatus: http.StatusCreated,
		},
		{
			name: "missing_project_id",
			body: EnqueueWorkRequest{
				TaskType: "build",
				Spec:     map[string]any{},
			},
			wantStatus: http.StatusBadRequest,
		},
		{
			name: "missing_task_type",
			body: EnqueueWorkRequest{
				ProjectID: "test-project",
				Spec:      map[string]any{},
			},
			wantStatus: http.StatusBadRequest,
		},
		{
			name: "invalid_task_type",
			body: EnqueueWorkRequest{
				ProjectID: "test-project",
				TaskType:  "invalid",
				Spec:      map[string]any{},
			},
			wantStatus: http.StatusBadRequest,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			body, _ := json.Marshal(tt.body)
			req := httptest.NewRequest(http.MethodPost, "/work/enqueue", bytes.NewReader(body))
			req.Header.Set("Content-Type", "application/json")
			rec := httptest.NewRecorder()

			router.ServeHTTP(rec, req)

			if rec.Code != tt.wantStatus {
				t.Errorf("got status %d, want %d; body: %s", rec.Code, tt.wantStatus, rec.Body.String())
			}
		})
	}
}

func TestWorkHandler_Dequeue(t *testing.T) {
	mockQueue := newMockWorkQueue()
	workService := service.NewWorkService(mockQueue, service.WorkServiceConfig{})
	handler := NewWorkHandler(workService)

	// Pre-populate a pending task
	mockQueue.tasks["task-1"] = &domain.WorkTask{
		ID:        "task-1",
		ProjectID: "test-project",
		Type:      domain.WorkTaskTypeBuild,
		Status:    domain.WorkTaskStatusPending,
		CreatedAt: time.Now(),
	}

	router := chi.NewRouter()
	handler.Mount(router)

	tests := []struct {
		name       string
		body       DequeueWorkRequest
		wantStatus int
		wantTask   bool
	}{
		{
			name:       "valid_dequeue",
			body:       DequeueWorkRequest{WorkerID: "worker-1"},
			wantStatus: http.StatusOK,
			wantTask:   true,
		},
		{
			name:       "missing_worker_id",
			body:       DequeueWorkRequest{},
			wantStatus: http.StatusBadRequest,
			wantTask:   false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			body, _ := json.Marshal(tt.body)
			req := httptest.NewRequest(http.MethodPost, "/work/dequeue", bytes.NewReader(body))
			req.Header.Set("Content-Type", "application/json")
			rec := httptest.NewRecorder()

			router.ServeHTTP(rec, req)

			if rec.Code != tt.wantStatus {
				t.Errorf("got status %d, want %d; body: %s", rec.Code, tt.wantStatus, rec.Body.String())
			}

			if tt.wantTask && rec.Code == http.StatusOK {
				var resp map[string]any
				if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
					t.Fatalf("failed to unmarshal response: %v", err)
				}
				data, ok := resp["data"].(map[string]any)
				if !ok {
					t.Fatal("response missing data field")
				}
				if data["task"] == nil {
					t.Error("expected task in response")
				}
			}
		})
	}
}

func TestWorkHandler_Complete(t *testing.T) {
	mockQueue := newMockWorkQueue()
	workService := service.NewWorkService(mockQueue, service.WorkServiceConfig{})
	handler := NewWorkHandler(workService)

	// Pre-populate a running task
	mockQueue.tasks["task-1"] = &domain.WorkTask{
		ID:        "task-1",
		ProjectID: "test-project",
		Type:      domain.WorkTaskTypeBuild,
		Status:    domain.WorkTaskStatusRunning,
		WorkerID:  "worker-1",
		CreatedAt: time.Now(),
	}

	router := chi.NewRouter()
	handler.Mount(router)

	tests := []struct {
		name       string
		taskID     string
		body       CompleteWorkRequest
		wantStatus int
	}{
		{
			name:   "valid_complete",
			taskID: "task-1",
			body: CompleteWorkRequest{
				Output: "Build successful",
				Artifacts: map[string]string{
					"commit_sha": "abc123",
				},
			},
			wantStatus: http.StatusOK,
		},
		{
			name:       "task_not_found",
			taskID:     "nonexistent",
			body:       CompleteWorkRequest{Output: "Done"},
			wantStatus: http.StatusNotFound,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			body, _ := json.Marshal(tt.body)
			req := httptest.NewRequest(http.MethodPost, "/work/"+tt.taskID+"/complete", bytes.NewReader(body))
			req.Header.Set("Content-Type", "application/json")
			rec := httptest.NewRecorder()

			router.ServeHTTP(rec, req)

			if rec.Code != tt.wantStatus {
				t.Errorf("got status %d, want %d; body: %s", rec.Code, tt.wantStatus, rec.Body.String())
			}
		})
	}
}