package handler

import (
	"net/http"
	"net/http/httptest"
	"testing"

	"github.com/gin-gonic/gin"
	"github.com/stretchr/testify/assert"

	apierrors "github.com/user-management-system/internal/pkg/errors"
)

// TestHandleError_Nil 测试 nil error
func TestHandleError_Nil(t *testing.T) {
	gin.SetMode(gin.TestMode)
	w := &mockResponseWriter{}
	c, _ := gin.CreateTestContext(w)

	handleError(c, nil)
	// nil error 不写入响应
	assert.Equal(t, 0, w.code)
}

// TestHandleError_ApplicationError 测试 ApplicationError
func TestHandleError_ApplicationError(t *testing.T) {
	gin.SetMode(gin.TestMode)

	tests := []struct {
		name       string
		err        error
		wantStatus int
		wantCode   int
	}{
		{
			name:       "bad request error",
			err:        apierrors.BadRequest("invalid", "invalid input"),
			wantStatus: http.StatusBadRequest,
			wantCode:   http.StatusBadRequest,
		},
		{
			name:       "not found error",
			err:        apierrors.NotFound("user", "user not found"),
			wantStatus: http.StatusNotFound,
			wantCode:   http.StatusNotFound,
		},
		{
			name:       "unauthorized error",
			err:        apierrors.Unauthorized("token", "invalid token"),
			wantStatus: http.StatusUnauthorized,
			wantCode:   http.StatusUnauthorized,
		},
		{
			name:       "forbidden error",
			err:        apierrors.Forbidden("permission", "permission denied"),
			wantStatus: http.StatusForbidden,
			wantCode:   http.StatusForbidden,
		},
		{
			name:       "conflict error",
			err:        apierrors.Conflict("user", "user already exists"),
			wantStatus: http.StatusConflict,
			wantCode:   http.StatusConflict,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			w := &mockResponseWriter{}
			c, _ := gin.CreateTestContext(w)
			handleError(c, tt.err)
			assert.Equal(t, tt.wantStatus, w.code)
		})
	}
}

// TestClassifyErrorMessage 测试错误消息分类
func TestClassifyErrorMessage(t *testing.T) {
	tests := []struct {
		name string
		msg  string
		want int
	}{
		// Not found
		{name: "not found EN", msg: "user not found", want: http.StatusNotFound},
		{name: "not found CN", msg: "用户不存在", want: http.StatusNotFound},
		{name: "not found CN2", msg: "找不到资源", want: http.StatusNotFound},

		// Conflict
		{name: "already exists EN", msg: "user already exists", want: http.StatusConflict},
		{name: "already exists CN", msg: "用户已存在", want: http.StatusConflict},
		{name: "duplicate", msg: "duplicate entry", want: http.StatusConflict},

		// Unauthorized
		{name: "unauthorized EN", msg: "unauthorized", want: http.StatusUnauthorized},
		{name: "invalid token", msg: "invalid token", want: http.StatusUnauthorized},
		{name: "token", msg: "token expired", want: http.StatusUnauthorized},
		{name: "unauthorized CN", msg: "令牌无效", want: http.StatusUnauthorized},

		// Forbidden
		{name: "forbidden EN", msg: "forbidden", want: http.StatusForbidden},
		{name: "permission", msg: "no permission", want: http.StatusForbidden},
		{name: "forbidden CN", msg: "权限不足", want: http.StatusForbidden},

		// Bad request
		{name: "invalid", msg: "invalid input", want: http.StatusBadRequest},
		{name: "required", msg: "field is required", want: http.StatusBadRequest},
		{name: "cannot be empty", msg: "name cannot be empty", want: http.StatusBadRequest},
		{name: "cannot be empty CN", msg: "名称不能为空", want: http.StatusBadRequest},
		{name: "incorrect password", msg: "密码不正确", want: http.StatusBadRequest},
		{name: "expired", msg: "token expired", want: http.StatusUnauthorized}, // "token" 匹配先于 "expired"

		// Rate limit
		{name: "locked", msg: "account locked", want: http.StatusTooManyRequests},
		{name: "too many", msg: "too many attempts", want: http.StatusTooManyRequests},
		{name: "rate limit", msg: "rate limit exceeded", want: http.StatusTooManyRequests},

		// Internal server error (default)
		{name: "unknown error", msg: "unknown error occurred", want: http.StatusInternalServerError},
		{name: "database error", msg: "database connection failed", want: http.StatusInternalServerError},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := classifyErrorMessage(tt.msg)
			assert.Equal(t, tt.want, got, "classifyErrorMessage(%q)", tt.msg)
		})
	}
}

// TestContains 测试 contains 辅助函数
func TestContains(t *testing.T) {
	tests := []struct {
		name     string
		s        string
		keywords []string
		want     bool
	}{
		{
			name:     "match first",
			s:        "hello world",
			keywords: []string{"hello", "foo"},
			want:     true,
		},
		{
			name:     "match second",
			s:        "hello world",
			keywords: []string{"foo", "world"},
			want:     true,
		},
		{
			name:     "no match",
			s:        "hello world",
			keywords: []string{"foo", "bar"},
			want:     false,
		},
		{
			name:     "empty keywords",
			s:        "hello world",
			keywords: []string{},
			want:     false,
		},
		{
			name:     "empty string",
			s:        "",
			keywords: []string{"hello"},
			want:     false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := contains(tt.s, tt.keywords...)
			assert.Equal(t, tt.want, got)
		})
	}
}

// TestGetUserIDFromContext_Success 测试从 context 获取 userID
func TestGetUserIDFromContext_Success(t *testing.T) {
	gin.SetMode(gin.TestMode)
	w := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(w)

	c.Set("user_id", int64(123))

	userID, ok := getUserIDFromContext(c)
	assert.True(t, ok)
	assert.Equal(t, int64(123), userID)
}

// TestGetUserIDFromContext_NotExists 测试 context 中无 userID
func TestGetUserIDFromContext_NotExists(t *testing.T) {
	gin.SetMode(gin.TestMode)
	w := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(w)

	userID, ok := getUserIDFromContext(c)
	assert.False(t, ok)
	assert.Equal(t, int64(0), userID)
}

// TestGetUserIDFromContext_WrongType 测试 userID 类型错误
func TestGetUserIDFromContext_WrongType(t *testing.T) {
	gin.SetMode(gin.TestMode)
	w := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(w)

	c.Set("user_id", "not an int64")

	userID, ok := getUserIDFromContext(c)
	assert.False(t, ok)
	assert.Equal(t, int64(0), userID)
}

// TestGetUsernameFromContext_Success 测试从 context 获取 username
func TestGetUsernameFromContext_Success(t *testing.T) {
	gin.SetMode(gin.TestMode)
	w := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(w)

	c.Set("username", "testuser")

	username, ok := getUsernameFromContext(c)
	assert.True(t, ok)
	assert.Equal(t, "testuser", username)
}

// TestGetUsernameFromContext_NotExists 测试 context 中无 username
func TestGetUsernameFromContext_NotExists(t *testing.T) {
	gin.SetMode(gin.TestMode)
	w := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(w)

	username, ok := getUsernameFromContext(c)
	assert.False(t, ok)
	assert.Equal(t, "", username)
}

// TestGetUsernameFromContext_WrongType 测试 username 类型错误
func TestGetUsernameFromContext_WrongType(t *testing.T) {
	gin.SetMode(gin.TestMode)
	w := httptest.NewRecorder()
	c, _ := gin.CreateTestContext(w)

	c.Set("username", 12345)

	username, ok := getUsernameFromContext(c)
	assert.False(t, ok)
	assert.Equal(t, "", username)
}

// mockResponseWriter 用于测试的 mock response writer
type mockResponseWriter struct {
	code int
	data []byte
}

func (m *mockResponseWriter) Header() http.Header {
	return http.Header{}
}

func (m *mockResponseWriter) Write(data []byte) (int, error) {
	m.data = append(m.data, data...)
	return len(data), nil
}

func (m *mockResponseWriter) WriteHeader(code int) {
	m.code = code
}