package product_test

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

	"github.com/food-ai/backend/internal/domain/product"
	productmocks "github.com/food-ai/backend/internal/domain/product/mocks"
	"github.com/food-ai/backend/internal/infra/middleware"
	"github.com/go-chi/chi/v5"
)

type alwaysAuthValidator struct{ userID string }

func (v *alwaysAuthValidator) ValidateAccessToken(_ string) (*middleware.TokenClaims, error) {
	return &middleware.TokenClaims{UserID: v.userID}, nil
}

func buildRouter(handler *product.Handler, userID string) *chi.Mux {
	router := chi.NewRouter()
	router.Use(middleware.Auth(&alwaysAuthValidator{userID: userID}))
	router.Get("/products", handler.List)
	router.Post("/products", handler.Create)
	router.Post("/products/batch", handler.BatchCreate)
	router.Put("/products/{id}", handler.Update)
	router.Delete("/products/{id}", handler.Delete)
	return router
}

func authorizedRequest(method, target string, body []byte) *http.Request {
	request := httptest.NewRequest(method, target, bytes.NewReader(body))
	request.Header.Set("Authorization", "Bearer test-token")
	request.Header.Set("Content-Type", "application/json")
	return request
}

func makeProduct(name string) *product.Product {
	return &product.Product{
		ID:          "prod-1",
		UserID:      "user-1",
		Name:        name,
		Quantity:    1,
		Unit:        "pcs",
		StorageDays: 7,
		AddedAt:     time.Now(),
		ExpiresAt:   time.Now().AddDate(0, 0, 7),
		DaysLeft:    7,
	}
}

func TestList_Success(t *testing.T) {
	mockRepo := &productmocks.MockProductRepository{
		ListFn: func(ctx context.Context, userID string) ([]*product.Product, error) {
			return []*product.Product{makeProduct("Milk")}, nil
		},
	}
	handler := product.NewHandler(mockRepo)
	router := buildRouter(handler, "user-1")

	recorder := httptest.NewRecorder()
	router.ServeHTTP(recorder, authorizedRequest(http.MethodGet, "/products", nil))

	if recorder.Code != http.StatusOK {
		t.Errorf("expected 200, got %d", recorder.Code)
	}
}

func TestCreate_MissingName(t *testing.T) {
	handler := product.NewHandler(&productmocks.MockProductRepository{})
	router := buildRouter(handler, "user-1")

	body, _ := json.Marshal(map[string]any{"quantity": 1})
	recorder := httptest.NewRecorder()
	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/products", body))

	if recorder.Code != http.StatusBadRequest {
		t.Errorf("expected 400, got %d", recorder.Code)
	}
}

func TestCreate_Success(t *testing.T) {
	mockRepo := &productmocks.MockProductRepository{
		CreateFn: func(ctx context.Context, userID string, req product.CreateRequest) (*product.Product, error) {
			return makeProduct(req.Name), nil
		},
	}
	handler := product.NewHandler(mockRepo)
	router := buildRouter(handler, "user-1")

	body, _ := json.Marshal(product.CreateRequest{Name: "Milk", Quantity: 1, Unit: "L"})
	recorder := httptest.NewRecorder()
	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/products", body))

	if recorder.Code != http.StatusCreated {
		t.Errorf("expected 201, got %d", recorder.Code)
	}
}

func TestBatchCreate_Success(t *testing.T) {
	mockRepo := &productmocks.MockProductRepository{
		BatchCreateFn: func(ctx context.Context, userID string, items []product.CreateRequest) ([]*product.Product, error) {
			result := make([]*product.Product, len(items))
			for index, item := range items {
				result[index] = makeProduct(item.Name)
			}
			return result, nil
		},
	}
	handler := product.NewHandler(mockRepo)
	router := buildRouter(handler, "user-1")

	body, _ := json.Marshal([]product.CreateRequest{
		{Name: "Milk", Quantity: 1, Unit: "L"},
		{Name: "Eggs", Quantity: 12, Unit: "pcs"},
	})
	recorder := httptest.NewRecorder()
	router.ServeHTTP(recorder, authorizedRequest(http.MethodPost, "/products/batch", body))

	if recorder.Code != http.StatusCreated {
		t.Errorf("expected 201, got %d", recorder.Code)
	}
}

func TestUpdate_NotFound(t *testing.T) {
	mockRepo := &productmocks.MockProductRepository{
		UpdateFn: func(ctx context.Context, id, userID string, req product.UpdateRequest) (*product.Product, error) {
			return nil, product.ErrNotFound
		},
	}
	handler := product.NewHandler(mockRepo)
	router := buildRouter(handler, "user-1")

	namePtr := "NewName"
	body, _ := json.Marshal(product.UpdateRequest{Name: &namePtr})
	recorder := httptest.NewRecorder()
	router.ServeHTTP(recorder, authorizedRequest(http.MethodPut, "/products/nonexistent", body))

	if recorder.Code != http.StatusNotFound {
		t.Errorf("expected 404, got %d", recorder.Code)
	}
}

func TestUpdate_Success(t *testing.T) {
	mockRepo := &productmocks.MockProductRepository{
		UpdateFn: func(ctx context.Context, id, userID string, req product.UpdateRequest) (*product.Product, error) {
			updated := makeProduct(*req.Name)
			return updated, nil
		},
	}
	handler := product.NewHandler(mockRepo)
	router := buildRouter(handler, "user-1")

	namePtr := "Oat Milk"
	body, _ := json.Marshal(product.UpdateRequest{Name: &namePtr})
	recorder := httptest.NewRecorder()
	router.ServeHTTP(recorder, authorizedRequest(http.MethodPut, "/products/prod-1", body))

	if recorder.Code != http.StatusOK {
		t.Errorf("expected 200, got %d", recorder.Code)
	}
}

func TestDelete_NotFound(t *testing.T) {
	mockRepo := &productmocks.MockProductRepository{
		DeleteFn: func(ctx context.Context, id, userID string) error {
			return product.ErrNotFound
		},
	}
	handler := product.NewHandler(mockRepo)
	router := buildRouter(handler, "user-1")

	recorder := httptest.NewRecorder()
	router.ServeHTTP(recorder, authorizedRequest(http.MethodDelete, "/products/nonexistent", nil))

	if recorder.Code != http.StatusNotFound {
		t.Errorf("expected 404, got %d", recorder.Code)
	}
}

func TestDelete_Success(t *testing.T) {
	mockRepo := &productmocks.MockProductRepository{
		DeleteFn: func(ctx context.Context, id, userID string) error {
			return nil
		},
	}
	handler := product.NewHandler(mockRepo)
	router := buildRouter(handler, "user-1")

	recorder := httptest.NewRecorder()
	router.ServeHTTP(recorder, authorizedRequest(http.MethodDelete, "/products/prod-1", nil))

	if recorder.Code != http.StatusNoContent {
		t.Errorf("expected 204, got %d", recorder.Code)
	}
}