package api

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

// newTestTodoistClient creates a TodoistClient for testing with custom base URL
func newTestTodoistClient(baseURL, apiKey string) *TodoistClient {
	client := NewTodoistClient(apiKey)
	client.BaseURL = baseURL
	client.syncClient.BaseURL = baseURL
	return client
}

func TestTodoistClient_CreateTask(t *testing.T) {
	// Mock server
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Verify method and path
		if r.Method != "POST" {
			t.Errorf("Expected POST request, got %s", r.Method)
		}
		if r.URL.Path != "/tasks" {
			t.Errorf("Expected path /tasks, got %s", r.URL.Path)
		}

		// Verify Authorization header
		if !strings.HasPrefix(r.Header.Get("Authorization"), "Bearer ") {
			t.Errorf("Expected Bearer token in Authorization header")
		}

		// Parse JSON body
		var payload map[string]interface{}
		if err := json.NewDecoder(r.Body).Decode(&payload); err != nil {
			t.Errorf("Failed to decode request body: %v", err)
		}

		// Verify content
		if payload["content"] != "Test Task" {
			t.Errorf("Expected content=Test Task, got %v", payload["content"])
		}

		if payload["project_id"] != "project-123" {
			t.Errorf("Expected project_id=project-123, got %v", payload["project_id"])
		}

		// Return mock response
		response := todoistTaskResponse{
			ID:          "task-456",
			Content:     "Test Task",
			Description: "",
			ProjectID:   "project-123",
			Priority:    1,
			Labels:      []string{},
			URL:         "https://todoist.com/task/456",
			CreatedAt:   time.Now().Format(time.RFC3339),
		}

		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(response)
	}))
	defer server.Close()

	// Create client with mock server URL
	client := newTestTodoistClient(server.URL, "test-key")

	// Test CreateTask
	ctx := context.Background()
	task, err := client.CreateTask(ctx, "Test Task", "project-123", nil, 0)

	if err != nil {
		t.Fatalf("CreateTask failed: %v", err)
	}

	// Verify response
	if task.ID != "task-456" {
		t.Errorf("Expected task ID task-456, got %s", task.ID)
	}
	if task.Content != "Test Task" {
		t.Errorf("Expected task content Test Task, got %s", task.Content)
	}
	if task.ProjectID != "project-123" {
		t.Errorf("Expected project ID project-123, got %s", task.ProjectID)
	}
}

func TestTodoistClient_CreateTask_WithDueDate(t *testing.T) {
	dueDate := time.Date(2026, 1, 15, 0, 0, 0, 0, time.UTC)

	// Mock server
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Parse JSON body
		var payload map[string]interface{}
		_ = json.NewDecoder(r.Body).Decode(&payload)

		// Verify due_date
		if payload["due_date"] != "2026-01-15" {
			t.Errorf("Expected due_date=2026-01-15, got %v", payload["due_date"])
		}

		// Return mock response with due date
		response := todoistTaskResponse{
			ID:        "task-789",
			Content:   "Task with Due Date",
			ProjectID: "project-456",
			URL:       "https://todoist.com/task/789",
			CreatedAt: time.Now().Format(time.RFC3339),
			Due: &dueInfo{
				Date:     "2026-01-15",
				Datetime: "",
			},
		}

		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(response)
	}))
	defer server.Close()

	// Create client
	client := newTestTodoistClient(server.URL, "test-key")

	// Test CreateTask with due date
	ctx := context.Background()
	task, err := client.CreateTask(ctx, "Task with Due Date", "project-456", &dueDate, 0)

	if err != nil {
		t.Fatalf("CreateTask failed: %v", err)
	}

	// Verify due date is set
	if task.DueDate == nil {
		t.Error("Expected due date to be set")
	} else {
		expectedDate := time.Date(2026, 1, 15, 0, 0, 0, 0, time.UTC)
		if !task.DueDate.Equal(expectedDate) {
			t.Errorf("Expected due date %v, got %v", expectedDate, *task.DueDate)
		}
	}
}

func TestTodoistClient_CompleteTask(t *testing.T) {
	// Mock server
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Verify method and path
		if r.Method != "POST" {
			t.Errorf("Expected POST request, got %s", r.Method)
		}
		expectedPath := "/tasks/task-123/close"
		if r.URL.Path != expectedPath {
			t.Errorf("Expected path %s, got %s", expectedPath, r.URL.Path)
		}

		// Verify Authorization header
		if !strings.HasPrefix(r.Header.Get("Authorization"), "Bearer ") {
			t.Errorf("Expected Bearer token in Authorization header")
		}

		// Return 204 No Content
		w.WriteHeader(http.StatusNoContent)
	}))
	defer server.Close()

	// Create client
	client := newTestTodoistClient(server.URL, "test-key")

	// Test CompleteTask
	ctx := context.Background()
	err := client.CompleteTask(ctx, "task-123")

	if err != nil {
		t.Fatalf("CompleteTask failed: %v", err)
	}
}

func TestTodoistClient_CompleteTask_Error(t *testing.T) {
	// Mock server that returns error
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusNotFound)
		_, _ = w.Write([]byte(`{"error":"Task not found"}`))
	}))
	defer server.Close()

	// Create client
	client := newTestTodoistClient(server.URL, "test-key")

	// Test CompleteTask with error
	ctx := context.Background()
	err := client.CompleteTask(ctx, "invalid-task")

	if err == nil {
		t.Error("Expected error, got nil")
	}
	if !strings.Contains(err.Error(), "404") {
		t.Errorf("Expected error to contain status 404, got: %v", err)
	}
}

func TestTodoistClient_GetProjects(t *testing.T) {
	// Mock server
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Verify method and path
		if r.Method != "GET" {
			t.Errorf("Expected GET request, got %s", r.Method)
		}
		if r.URL.Path != "/projects" {
			t.Errorf("Expected path /projects, got %s", r.URL.Path)
		}

		// Return mock response
		response := []todoistProjectResponse{
			{ID: "proj-1", Name: "Project 1"},
			{ID: "proj-2", Name: "Project 2"},
		}

		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(response)
	}))
	defer server.Close()

	// Create client
	client := newTestTodoistClient(server.URL, "test-key")

	// Test GetProjects
	ctx := context.Background()
	projects, err := client.GetProjects(ctx)

	if err != nil {
		t.Fatalf("GetProjects failed: %v", err)
	}

	// Verify response
	if len(projects) != 2 {
		t.Errorf("Expected 2 projects, got %d", len(projects))
	}

	if projects[0].ID != "proj-1" || projects[0].Name != "Project 1" {
		t.Errorf("Project 1 mismatch: got ID=%s Name=%s", projects[0].ID, projects[0].Name)
	}

	if projects[1].ID != "proj-2" || projects[1].Name != "Project 2" {
		t.Errorf("Project 2 mismatch: got ID=%s Name=%s", projects[1].ID, projects[1].Name)
	}
}

func TestTodoistClient_GetTasks(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "GET" {
			t.Errorf("Expected GET, got %s", r.Method)
		}

		w.Header().Set("Content-Type", "application/json")

		// GetTasks also calls GetProjects internally
		if r.URL.Path == "/projects" {
			response := []todoistProjectResponse{
				{ID: "proj-1", Name: "Project 1"},
			}
			json.NewEncoder(w).Encode(response)
			return
		}

		if r.URL.Path == "/tasks" {
			response := []todoistTaskResponse{
				{ID: "task-1", Content: "Task 1", ProjectID: "proj-1", CreatedAt: time.Now().Format(time.RFC3339)},
				{ID: "task-2", Content: "Task 2", ProjectID: "proj-1", CreatedAt: time.Now().Format(time.RFC3339)},
			}
			json.NewEncoder(w).Encode(response)
			return
		}

		t.Errorf("Unexpected path: %s", r.URL.Path)
	}))
	defer server.Close()

	client := newTestTodoistClient(server.URL, "test-key")
	tasks, err := client.GetTasks(context.Background())
	if err != nil {
		t.Fatalf("GetTasks failed: %v", err)
	}

	if len(tasks) != 2 {
		t.Errorf("Expected 2 tasks, got %d", len(tasks))
	}
}

func TestTodoistClient_ReopenTask(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "POST" {
			t.Errorf("Expected POST, got %s", r.Method)
		}
		expectedPath := "/tasks/task-123/reopen"
		if r.URL.Path != expectedPath {
			t.Errorf("Expected path %s, got %s", expectedPath, r.URL.Path)
		}

		w.WriteHeader(http.StatusNoContent)
	}))
	defer server.Close()

	client := newTestTodoistClient(server.URL, "test-key")
	err := client.ReopenTask(context.Background(), "task-123")
	if err != nil {
		t.Fatalf("ReopenTask failed: %v", err)
	}
}

func TestTodoistClient_UpdateTask(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "POST" {
			t.Errorf("Expected POST, got %s", r.Method)
		}
		expectedPath := "/tasks/task-123"
		if r.URL.Path != expectedPath {
			t.Errorf("Expected path %s, got %s", expectedPath, r.URL.Path)
		}

		var payload map[string]interface{}
		json.NewDecoder(r.Body).Decode(&payload)
		if payload["content"] != "Updated Content" {
			t.Errorf("Expected content 'Updated Content', got %v", payload["content"])
		}

		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]string{"id": "task-123"})
	}))
	defer server.Close()

	client := newTestTodoistClient(server.URL, "test-key")
	err := client.UpdateTask(context.Background(), "task-123", map[string]interface{}{"content": "Updated Content"})
	if err != nil {
		t.Fatalf("UpdateTask failed: %v", err)
	}
}

func TestTodoistClient_Sync(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "POST" {
			t.Errorf("Expected POST, got %s", r.Method)
		}
		if r.URL.Path != "/sync" {
			t.Errorf("Expected path /sync, got %s", r.URL.Path)
		}

		response := TodoistSyncResponse{
			SyncToken: "new-sync-token",
			FullSync:  true,
			Items: []SyncItemResponse{
				{ID: "item-1", Content: "Item 1", ProjectID: "proj-1"},
			},
			Projects: []SyncProjectResponse{
				{ID: "proj-1", Name: "Project 1"},
			},
		}

		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(response)
	}))
	defer server.Close()

	client := newTestTodoistClient(server.URL, "test-key")
	resp, err := client.Sync(context.Background(), "*")
	if err != nil {
		t.Fatalf("Sync failed: %v", err)
	}

	if resp.SyncToken != "new-sync-token" {
		t.Errorf("Expected sync token 'new-sync-token', got '%s'", resp.SyncToken)
	}
	if len(resp.Items) != 1 {
		t.Errorf("Expected 1 item, got %d", len(resp.Items))
	}
}

func TestConvertSyncItemsToTasks(t *testing.T) {
	projects := map[string]string{
		"proj-1": "Project 1",
	}

	items := []SyncItemResponse{
		{
			ID:          "item-1",
			Content:     "Task 1",
			Description: "Description 1",
			ProjectID:   "proj-1",
			Priority:    3,
			Labels:      []string{"label1"},
		},
		{
			ID:          "item-2",
			Content:     "Completed Task",
			ProjectID:   "proj-1",
			IsCompleted: true,
		},
	}

	tasks := ConvertSyncItemsToTasks(items, projects)

	// Should skip completed task
	if len(tasks) != 1 {
		t.Errorf("Expected 1 task (excluding completed), got %d", len(tasks))
	}

	if tasks[0].ID != "item-1" {
		t.Errorf("Expected task ID 'item-1', got '%s'", tasks[0].ID)
	}
	if tasks[0].ProjectName != "Project 1" {
		t.Errorf("Expected project name 'Project 1', got '%s'", tasks[0].ProjectName)
	}
}

func TestBuildProjectMapFromSync(t *testing.T) {
	projects := []SyncProjectResponse{
		{ID: "proj-1", Name: "Project 1"},
		{ID: "proj-2", Name: "Project 2"},
	}

	projectMap := BuildProjectMapFromSync(projects)

	if len(projectMap) != 2 {
		t.Errorf("Expected 2 projects in map, got %d", len(projectMap))
	}

	if projectMap["proj-1"] != "Project 1" {
		t.Errorf("Expected 'Project 1', got '%s'", projectMap["proj-1"])
	}
}