package health

import (
	"context"
	"sync"
	"time"
)

type CheckFunc func(context.Context) error

type Checker struct {
	timeout time.Duration
	checks  map[string]CheckFunc
}

type Result struct {
	Status string            `json:"status"`
	Checks map[string]string `json:"checks"`
}

func NewChecker(timeout time.Duration, checks map[string]CheckFunc) *Checker {
	return &Checker{timeout: timeout, checks: checks}
}

func (c *Checker) Ready(ctx context.Context) Result {
	result := Result{Status: "ready", Checks: make(map[string]string, len(c.checks))}
	var mutex sync.Mutex
	var waitGroup sync.WaitGroup

	for name, check := range c.checks {
		name, check := name, check
		waitGroup.Add(1)
		go func() {
			defer waitGroup.Done()
			checkContext, cancel := context.WithTimeout(ctx, c.timeout)
			defer cancel()
			status := "up"
			if err := check(checkContext); err != nil {
				status = "down"
			}
			mutex.Lock()
			result.Checks[name] = status
			if status == "down" {
				result.Status = "not_ready"
			}
			mutex.Unlock()
		}()
	}
	waitGroup.Wait()
	return result
}