package pow

import (
	"crypto/rand"
	"encoding/hex"
	"time"
)

// TestConfig returns a configuration suitable for testing
func TestConfig() *Config {
	secret := make([]byte, 32)
	rand.Read(secret)

	return &Config{
		DefaultDifficulty:     4,
		MaxDifficulty:         10,
		MinDifficulty:         3,
		ChallengeTTL:          5 * time.Minute,
		HMACSecret:            secret,
		Resource:              "quotes",
		LoadAdjustmentBits:    1,
		FailurePenaltyBits:    2,
		MaxFailurePenaltyBits: 6,
	}
}

// TestChallenge returns a valid challenge for testing
func TestChallenge() *Challenge {
	return &Challenge{
		Timestamp:  time.Now().Unix(),
		Difficulty: 4,
		Resource:   "quotes",
		Random:     "a1b2c3d4e5f6",
		HMAC:       "", // To be filled by generator
	}
}

// TestSolution returns a valid solution for testing
func TestSolution() *Solution {
	return &Solution{
		Challenge: *TestChallenge(),
		Nonce:     "42",
	}
}

// RandomHex generates a random hex string of given length
func RandomHex(length int) string {
	bytes := make([]byte, length/2)
	rand.Read(bytes)
	return hex.EncodeToString(bytes)
}

// ExpiredChallenge returns a challenge that has expired
func ExpiredChallenge() *Challenge {
	challenge := TestChallenge()
	challenge.Timestamp = time.Now().Add(-10 * time.Minute).Unix()
	return challenge
}

// FutureChallenge returns a challenge with future timestamp
func FutureChallenge() *Challenge {
	challenge := TestChallenge()
	challenge.Timestamp = time.Now().Add(10 * time.Minute).Unix()
	return challenge
}