package api

import (
	"testing"
)

// MockUser 模擬用戶結構
type MockUser struct {
	ID          int
	Email       string
	OTPSecret   string
	OTPVerified bool
}

// TestOTPRefetchLogic 測試 OTP 重新獲取邏輯
func TestOTPRefetchLogic(t *testing.T) {
	tests := []struct {
		name            string
		existingUser    *MockUser
		userExists      bool
		expectedAction  string // "allow_refetch", "reject_duplicate", "create_new"
		expectedMessage string
	}{
		{
			name:            "新用戶註冊_郵箱不存在",
			existingUser:    nil,
			userExists:      false,
			expectedAction:  "create_new",
			expectedMessage: "創建新用戶",
		},
		{
			name: "未完成OTP驗證_允許重新獲取",
			existingUser: &MockUser{
				ID:          1,
				Email:       "test@example.com",
				OTPSecret:   "SECRET123",
				OTPVerified: false,
			},
			userExists:      true,
			expectedAction:  "allow_refetch",
			expectedMessage: "检测到未完成的注册，请继续完成OTP设置",
		},
		{
			name: "已完成OTP驗證_拒絕重複註冊",
			existingUser: &MockUser{
				ID:          2,
				Email:       "verified@example.com",
				OTPSecret:   "SECRET456",
				OTPVerified: true,
			},
			userExists:      true,
			expectedAction:  "reject_duplicate",
			expectedMessage: "邮箱已被注册",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			// 模擬邏輯處理流程
			var actualAction string
			var actualMessage string

			if !tt.userExists {
				// 用戶不存在，創建新用戶
				actualAction = "create_new"
				actualMessage = "創建新用戶"
			} else {
				// 用戶已存在，檢查 OTP 驗證狀態
				if !tt.existingUser.OTPVerified {
					// 未完成 OTP 驗證，允許重新獲取
					actualAction = "allow_refetch"
					actualMessage = "检测到未完成的注册，请继续完成OTP设置"
				} else {
					// 已完成驗證，拒絕重複註冊
					actualAction = "reject_duplicate"
					actualMessage = "邮箱已被注册"
				}
			}

			// 驗證結果
			if actualAction != tt.expectedAction {
				t.Errorf("Action 不符: got %s, want %s", actualAction, tt.expectedAction)
			}
			if actualMessage != tt.expectedMessage {
				t.Errorf("Message 不符: got %s, want %s", actualMessage, tt.expectedMessage)
			}
		})
	}
}

// TestOTPVerificationStates 測試 OTP 驗證狀態判斷
func TestOTPVerificationStates(t *testing.T) {
	tests := []struct {
		name               string
		otpVerified        bool
		shouldAllowRefetch bool
	}{
		{
			name:               "OTP已驗證_不允許重新獲取",
			otpVerified:        true,
			shouldAllowRefetch: false,
		},
		{
			name:               "OTP未驗證_允許重新獲取",
			otpVerified:        false,
			shouldAllowRefetch: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			// 模擬驗證邏輯
			allowRefetch := !tt.otpVerified

			if allowRefetch != tt.shouldAllowRefetch {
				t.Errorf("Refetch logic error: OTPVerified=%v, allowRefetch=%v, expected=%v",
					tt.otpVerified, allowRefetch, tt.shouldAllowRefetch)
			}
		})
	}
}

// TestRegistrationFlow 測試完整註冊流程的邏輯分支
func TestRegistrationFlow(t *testing.T) {
	tests := []struct {
		name           string
		scenario       string
		userExists     bool
		otpVerified    bool
		expectHTTPCode int // 模擬的 HTTP 狀態碼
		expectResponse string
	}{
		{
			name:           "場景1_新用戶首次註冊",
			scenario:       "新用戶首次訪問註冊接口",
			userExists:     false,
			otpVerified:    false,
			expectHTTPCode: 200,
			expectResponse: "創建用戶並返回 OTP 設置信息",
		},
		{
			name:           "場景2_用戶中斷註冊後重新訪問",
			scenario:       "用戶之前註冊但未完成 OTP 設置，現在重新訪問",
			userExists:     true,
			otpVerified:    false,
			expectHTTPCode: 200,
			expectResponse: "返回現有用戶的 OTP 信息，允許繼續完成",
		},
		{
			name:           "場景3_已註冊用戶嘗試重複註冊",
			scenario:       "用戶已完成註冊，嘗試用同一郵箱再次註冊",
			userExists:     true,
			otpVerified:    true,
			expectHTTPCode: 409, // Conflict
			expectResponse: "邮箱已被注册",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			// 模擬註冊流程邏輯
			var actualHTTPCode int
			var actualResponse string

			if !tt.userExists {
				// 新用戶，創建並返回 OTP 信息
				actualHTTPCode = 200
				actualResponse = "創建用戶並返回 OTP 設置信息"
			} else {
				// 用戶已存在
				if !tt.otpVerified {
					// 未完成 OTP 驗證，允許重新獲取
					actualHTTPCode = 200
					actualResponse = "返回現有用戶的 OTP 信息，允許繼續完成"
				} else {
					// 已完成驗證，拒絕重複註冊
					actualHTTPCode = 409
					actualResponse = "邮箱已被注册"
				}
			}

			// 驗證
			if actualHTTPCode != tt.expectHTTPCode {
				t.Errorf("HTTP code 不符: got %d, want %d (scenario: %s)",
					actualHTTPCode, tt.expectHTTPCode, tt.scenario)
			}
			if actualResponse != tt.expectResponse {
				t.Errorf("Response 不符: got %s, want %s (scenario: %s)",
					actualResponse, tt.expectResponse, tt.scenario)
			}

			t.Logf("✓ %s: HTTP %d, %s", tt.scenario, actualHTTPCode, actualResponse)
		})
	}
}

// TestEdgeCases 測試邊界情況
func TestEdgeCases(t *testing.T) {
	tests := []struct {
		name        string
		user        *MockUser
		expectAllow bool
		description string
	}{
		{
			name: "用戶ID為0_視為新用戶",
			user: &MockUser{
				ID:          0,
				Email:       "new@example.com",
				OTPVerified: false,
			},
			expectAllow: true,
			description: "ID為0通常表示用戶還未創建",
		},
		{
			name: "OTPSecret為空_仍可重新獲取",
			user: &MockUser{
				ID:          1,
				Email:       "test@example.com",
				OTPSecret:   "",
				OTPVerified: false,
			},
			expectAllow: true,
			description: "即使 OTPSecret 為空，只要未驗證就允許重新獲取",
		},
		{
			name: "OTPSecret存在但已驗證_不允許",
			user: &MockUser{
				ID:          2,
				Email:       "verified@example.com",
				OTPSecret:   "SECRET789",
				OTPVerified: true,
			},
			expectAllow: false,
			description: "OTP 已驗證的用戶不能重新獲取",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			// 核心邏輯：只要 OTPVerified 為 false，就允許重新獲取
			allowRefetch := !tt.user.OTPVerified

			if allowRefetch != tt.expectAllow {
				t.Errorf("Edge case failed: %s\nUser: ID=%d, OTPVerified=%v\nExpected allow=%v, got=%v",
					tt.description, tt.user.ID, tt.user.OTPVerified, tt.expectAllow, allowRefetch)
			}

			t.Logf("✓ %s", tt.description)
		})
	}
}