package health

// Status 健康状态
type Status string

const (
	StatusHealthy   Status = "healthy"
	StatusUnhealthy Status = "unhealthy"
	StatusDegraded  Status = "degraded"
)

// Check 健康检查接口
type Check interface {
	// Check 执行健康检查
	Check() (Status, string)
}

// Checker 健康检查器
type Checker interface {
	// Register 注册健康检查
	Register(name string, check Check) error

	// Unregister 取消注册健康检查
	Unregister(name string) error

	// Check 执行所有健康检查
	Check() (Status, map[string]CheckResult)
}

// CheckResult 健康检查结果
type CheckResult struct {
	Status  Status
	Message string
}

// checker 健康检查器实现
type checker struct {
	checks map[string]Check
}

// NewChecker 创建健康检查器
func NewChecker() Checker {
	return &checker{
		checks: make(map[string]Check),
	}
}

// Register 注册健康检查
func (c *checker) Register(name string, check Check) error {
	if name == "" {
		return NewError("check name cannot be empty")
	}

	if check == nil {
		return NewError("check cannot be nil")
	}

	c.checks[name] = check
	return nil
}

// Unregister 取消注册健康检查
func (c *checker) Unregister(name string) error {
	delete(c.checks, name)
	return nil
}

// Check 执行所有健康检查
func (c *checker) Check() (Status, map[string]CheckResult) {
	results := make(map[string]CheckResult)
	overallStatus := StatusHealthy

	for name, check := range c.checks {
		status, message := check.Check()
		results[name] = CheckResult{
			Status:  status,
			Message: message,
		}

		// 确定整体状态
		if status == StatusUnhealthy {
			overallStatus = StatusUnhealthy
		} else if status == StatusDegraded && overallStatus == StatusHealthy {
			overallStatus = StatusDegraded
		}
	}

	return overallStatus, results
}