// Exercise 03 — Token Bucket Rate Limiter
//
// ASSIGNMENT
// ----------
// Implement a token-bucket limiter:
//
//  1. NewLimiter(rate, burst): capacity `burst` tokens, refilled continuously
//     at `rate` tokens/second. Bucket starts FULL.
//  2. Allow() consumes one token and returns true, or returns false if no
//     token is available. Must be non-blocking and safe for concurrent use.
//  3. Refill must be LAZY — no background goroutine, no ticker. Compute the
//     accrued tokens from elapsed time inside Allow().
//  4. Tokens never exceed `burst` (idle time must not build infinite credit).
//
// Run the tests:   go test -race ./03-rate-limiter/
package main

import (
	"fmt"
	"time"
)

type Limiter struct {
	// TODO: fields (mutex, current tokens, max, rate, last refill time)
}

// NewLimiter returns a limiter allowing `rate` ops/sec with bursts up to `burst`.
// TODO: implement me.
func NewLimiter(rate float64, burst int) *Limiter {
	return &Limiter{}
}

// Allow reports whether one operation may proceed now.
// TODO: implement me.
func (l *Limiter) Allow() bool {
	return false
}

func main() {
	l := NewLimiter(5, 3) // 5/sec, burst 3
	for i := 0; i < 10; i++ {
		fmt.Printf("req %d: allowed=%v\n", i, l.Allow())
		time.Sleep(100 * time.Millisecond)
	}
}