module main

import rand
import time
import math

// ============================================================================
// Property 9: Retry Mechanism
// Feature: v-hono-upload-integration, Property 9: Retry Mechanism
// Validates: Requirements 9.1, 9.2, 9.3
//
// *For any* retryable error, the system should retry with exponential backoff,
// respect configured retry count, and return comprehensive error with retry
// history when all retries are exhausted.
// ============================================================================

const test_iterations = 100

// ============================================================================
// Type definitions (copied from retry.v and storage_errors.v for standalone testing)
// ============================================================================

// 存储错误类型枚举
enum StorageErrorKind {
	// 可重试错误
	network_timeout
	service_unavailable
	rate_limited
	connection_reset
	temporary_failure
	// 不可重试错误
	invalid_credentials
	access_denied
	bucket_not_found
	object_not_found
	invalid_object_key
	quota_exceeded
	invalid_config
	bucket_not_empty
	bucket_already_exists
	object_already_exists
	invalid_range
	checksum_mismatch
	// 其他错误
	unknown
}

// 重试尝试记录
struct RetryAttempt {
pub:
	attempt_number int
	timestamp      i64
	error_message  string
	delay_ms       int
}

// 存储错误结构
struct StorageError {
pub:
	kind        StorageErrorKind
	message     string
	provider    string
	operation   string
	http_status int
	retry_count int
	details     map[string]string
pub mut:
	retry_history []RetryAttempt
}


// 判断错误是否可重试
fn (e StorageError) is_retryable() bool {
	return e.kind in [
		.network_timeout,
		.service_unavailable,
		.rate_limited,
		.connection_reset,
		.temporary_failure,
	]
}

// 重试配置结构
struct RetryConfig {
pub:
	max_retries     int  = 3
	initial_delay   int  = 1000
	max_delay       int  = 30000
	multiplier      f64  = 2.0
	jitter          bool = true
	jitter_factor   f64  = 0.25
}

// 默认重试配置
fn default_retry_config() RetryConfig {
	return RetryConfig{
		max_retries: 3
		initial_delay: 1000
		max_delay: 30000
		multiplier: 2.0
		jitter: true
		jitter_factor: 0.25
	}
}

// 激进重试配置
fn aggressive_retry_config() RetryConfig {
	return RetryConfig{
		max_retries: 5
		initial_delay: 500
		max_delay: 10000
		multiplier: 1.5
		jitter: true
		jitter_factor: 0.2
	}
}

// 保守重试配置
fn conservative_retry_config() RetryConfig {
	return RetryConfig{
		max_retries: 2
		initial_delay: 2000
		max_delay: 60000
		multiplier: 3.0
		jitter: true
		jitter_factor: 0.3
	}
}

// 重试执行结果
struct RetryResult[T] {
pub:
	success       bool
	value         T
	total_retries int
	total_delay   int
	final_error   StorageError
	history       []RetryAttempt
}

// 重试执行器
struct RetryExecutor {
	config RetryConfig
}

// 创建重试执行器
fn new_retry_executor(config RetryConfig) RetryExecutor {
	return RetryExecutor{
		config: config
	}
}

// 使用默认配置创建重试执行器
fn new_default_retry_executor() RetryExecutor {
	return RetryExecutor{
		config: default_retry_config()
	}
}


// 计算下一次重试的延迟时间
fn (r RetryExecutor) calculate_delay(attempt int) int {
	// 指数退避: delay = initial_delay * (multiplier ^ attempt)
	base_delay := f64(r.config.initial_delay) * math.pow(r.config.multiplier, f64(attempt))
	
	// 限制最大延迟
	mut delay := int(math.min(base_delay, f64(r.config.max_delay)))
	
	// 添加随机抖动
	if r.config.jitter && delay > 0 {
		jitter_range := int(f64(delay) * r.config.jitter_factor)
		if jitter_range > 0 {
			jitter := rand.int_in_range(0, jitter_range * 2) or { 0 }
			delay = delay - jitter_range + jitter
		}
	}
	
	// 确保延迟不为负
	if delay < 0 {
		delay = 0
	}
	
	return delay
}

// 计算不带抖动的基础延迟（用于测试）
fn calculate_base_delay(config RetryConfig, attempt int) int {
	base_delay := f64(config.initial_delay) * math.pow(config.multiplier, f64(attempt))
	return int(math.min(base_delay, f64(config.max_delay)))
}

// ============================================================================
// Test infrastructure
// ============================================================================

struct PropertyTestStats {
mut:
	total_tests  int
	passed_tests int
	failed_tests int
}

fn (mut stats PropertyTestStats) run_property_test(test_name string, test_func fn () bool) {
	stats.total_tests++
	print('🔬 ${test_name}... ')

	if test_func() {
		stats.passed_tests++
		println('✅')
	} else {
		stats.failed_tests++
		println('❌')
	}
}

fn (stats PropertyTestStats) print_summary() {
	println('\n=== Retry Mechanism 属性测试总结 ===')
	println('总测试数: ${stats.total_tests}')
	println('通过: ${stats.passed_tests}')
	println('失败: ${stats.failed_tests}')

	if stats.failed_tests == 0 {
		println('🎉 所有属性测试通过！')
	} else {
		println('⚠️  有 ${stats.failed_tests} 个属性测试失败')
	}
}

fn generate_random_int(min int, max int) int {
	return rand.int_in_range(min, max) or { min }
}

fn generate_random_f64(min f64, max f64) f64 {
	return min + rand.f64() * (max - min)
}


// ============================================================================
// Property 9.1: Exponential Backoff Delay Calculation
// For any retry configuration and attempt number, the delay should follow
// exponential backoff formula: delay = initial_delay * (multiplier ^ attempt)
// Validates: Requirements 9.1
// ============================================================================
fn test_property_9_1_exponential_backoff() bool {
	for _ in 0 .. test_iterations {
		// Generate random config
		initial_delay := generate_random_int(100, 5000)
		max_delay := generate_random_int(10000, 60000)
		multiplier := generate_random_f64(1.5, 3.0)
		
		config := RetryConfig{
			max_retries: 5
			initial_delay: initial_delay
			max_delay: max_delay
			multiplier: multiplier
			jitter: false  // Disable jitter for deterministic testing
			jitter_factor: 0.0
		}
		
		executor := new_retry_executor(config)
		
		// Test multiple attempts
		for attempt in 0 .. 5 {
			actual_delay := executor.calculate_delay(attempt)
			expected_delay := calculate_base_delay(config, attempt)
			
			// Without jitter, delays should match exactly
			if actual_delay != expected_delay {
				println('  Failed: Attempt ${attempt} expected delay ${expected_delay} but got ${actual_delay}')
				return false
			}
			
			// Verify delay doesn't exceed max_delay
			if actual_delay > max_delay {
				println('  Failed: Delay ${actual_delay} exceeds max_delay ${max_delay}')
				return false
			}
		}
	}
	return true
}

// ============================================================================
// Property 9.2: Delay Increases with Each Attempt
// For any retry configuration without jitter, delay should increase
// (or stay at max) with each subsequent attempt
// Validates: Requirements 9.1
// ============================================================================
fn test_property_9_2_delay_increases() bool {
	for _ in 0 .. test_iterations {
		initial_delay := generate_random_int(100, 2000)
		max_delay := generate_random_int(10000, 60000)
		multiplier := generate_random_f64(1.5, 3.0)
		
		config := RetryConfig{
			max_retries: 5
			initial_delay: initial_delay
			max_delay: max_delay
			multiplier: multiplier
			jitter: false
			jitter_factor: 0.0
		}
		
		executor := new_retry_executor(config)
		
		mut prev_delay := 0
		for attempt in 0 .. 5 {
			current_delay := executor.calculate_delay(attempt)
			
			// Delay should be >= previous delay (monotonically increasing until max)
			if current_delay < prev_delay {
				println('  Failed: Delay decreased from ${prev_delay} to ${current_delay} at attempt ${attempt}')
				return false
			}
			
			prev_delay = current_delay
		}
	}
	return true
}


// ============================================================================
// Property 9.3: Max Delay is Respected
// For any retry configuration, delay should never exceed max_delay
// Validates: Requirements 9.2
// ============================================================================
fn test_property_9_3_max_delay_respected() bool {
	for _ in 0 .. test_iterations {
		initial_delay := generate_random_int(1000, 5000)
		max_delay := generate_random_int(5000, 20000)
		multiplier := generate_random_f64(2.0, 4.0)
		
		config := RetryConfig{
			max_retries: 10
			initial_delay: initial_delay
			max_delay: max_delay
			multiplier: multiplier
			jitter: true
			jitter_factor: 0.25
		}
		
		executor := new_retry_executor(config)
		
		// Test many attempts to ensure max_delay is always respected
		for attempt in 0 .. 20 {
			delay := executor.calculate_delay(attempt)
			
			// With jitter, delay can vary but should still be bounded
			// Max possible delay with jitter = max_delay + (max_delay * jitter_factor)
			max_possible := max_delay + int(f64(max_delay) * config.jitter_factor)
			
			if delay > max_possible {
				println('  Failed: Delay ${delay} exceeds max possible ${max_possible} at attempt ${attempt}')
				return false
			}
		}
	}
	return true
}

// ============================================================================
// Property 9.4: Jitter Adds Randomness Within Bounds
// For any retry configuration with jitter enabled, delay should vary
// within the jitter range
// Validates: Requirements 9.1
// ============================================================================
fn test_property_9_4_jitter_within_bounds() bool {
	for _ in 0 .. test_iterations {
		initial_delay := generate_random_int(1000, 3000)
		max_delay := generate_random_int(30000, 60000)
		multiplier := 2.0
		jitter_factor := generate_random_f64(0.1, 0.4)
		
		config := RetryConfig{
			max_retries: 5
			initial_delay: initial_delay
			max_delay: max_delay
			multiplier: multiplier
			jitter: true
			jitter_factor: jitter_factor
		}
		
		executor := new_retry_executor(config)
		
		for attempt in 0 .. 5 {
			base_delay := calculate_base_delay(config, attempt)
			jitter_range := int(f64(base_delay) * jitter_factor)
			
			// Calculate expected bounds
			min_expected := base_delay - jitter_range
			max_expected := base_delay + jitter_range
			
			// Test multiple times to verify randomness
			for _ in 0 .. 10 {
				delay := executor.calculate_delay(attempt)
				
				// Delay should be within jitter bounds (with some tolerance for edge cases)
				if delay < min_expected - 1 || delay > max_expected + 1 {
					println('  Failed: Delay ${delay} outside jitter bounds [${min_expected}, ${max_expected}] at attempt ${attempt}')
					return false
				}
			}
		}
	}
	return true
}


// ============================================================================
// Property 9.5: Retry Count Configuration is Respected
// For any retry configuration, the max_retries setting should be respected
// Validates: Requirements 9.2
// ============================================================================
fn test_property_9_5_retry_count_respected() bool {
	for _ in 0 .. test_iterations {
		max_retries := generate_random_int(1, 10)
		
		config := RetryConfig{
			max_retries: max_retries
			initial_delay: 100
			max_delay: 10000
			multiplier: 2.0
			jitter: false
			jitter_factor: 0.0
		}
		
		// Verify config stores the correct max_retries
		if config.max_retries != max_retries {
			println('  Failed: Config max_retries ${config.max_retries} != expected ${max_retries}')
			return false
		}
		
		// Verify executor uses the config
		executor := new_retry_executor(config)
		if executor.config.max_retries != max_retries {
			println('  Failed: Executor config max_retries ${executor.config.max_retries} != expected ${max_retries}')
			return false
		}
	}
	return true
}

// ============================================================================
// Property 9.6: Default Config Has Sensible Values
// The default retry configuration should have reasonable default values
// Validates: Requirements 9.2
// ============================================================================
fn test_property_9_6_default_config_values() bool {
	config := default_retry_config()
	
	// Verify default values
	if config.max_retries != 3 {
		println('  Failed: Default max_retries should be 3 but got ${config.max_retries}')
		return false
	}
	
	if config.initial_delay != 1000 {
		println('  Failed: Default initial_delay should be 1000 but got ${config.initial_delay}')
		return false
	}
	
	if config.max_delay != 30000 {
		println('  Failed: Default max_delay should be 30000 but got ${config.max_delay}')
		return false
	}
	
	if config.multiplier != 2.0 {
		println('  Failed: Default multiplier should be 2.0 but got ${config.multiplier}')
		return false
	}
	
	if !config.jitter {
		println('  Failed: Default jitter should be true')
		return false
	}
	
	if config.jitter_factor != 0.25 {
		println('  Failed: Default jitter_factor should be 0.25 but got ${config.jitter_factor}')
		return false
	}
	
	return true
}


// ============================================================================
// Property 9.7: Aggressive Config Has Shorter Delays
// The aggressive retry configuration should have shorter delays than default
// Validates: Requirements 9.2
// ============================================================================
fn test_property_9_7_aggressive_config() bool {
	default_config := default_retry_config()
	aggressive_config := aggressive_retry_config()
	
	// Aggressive should have more retries
	if aggressive_config.max_retries <= default_config.max_retries {
		println('  Failed: Aggressive max_retries should be > default')
		return false
	}
	
	// Aggressive should have shorter initial delay
	if aggressive_config.initial_delay >= default_config.initial_delay {
		println('  Failed: Aggressive initial_delay should be < default')
		return false
	}
	
	// Aggressive should have shorter max delay
	if aggressive_config.max_delay >= default_config.max_delay {
		println('  Failed: Aggressive max_delay should be < default')
		return false
	}
	
	// Aggressive should have smaller multiplier
	if aggressive_config.multiplier >= default_config.multiplier {
		println('  Failed: Aggressive multiplier should be < default')
		return false
	}
	
	return true
}

// ============================================================================
// Property 9.8: Conservative Config Has Longer Delays
// The conservative retry configuration should have longer delays than default
// Validates: Requirements 9.2
// ============================================================================
fn test_property_9_8_conservative_config() bool {
	default_config := default_retry_config()
	conservative_config := conservative_retry_config()
	
	// Conservative should have fewer retries
	if conservative_config.max_retries >= default_config.max_retries {
		println('  Failed: Conservative max_retries should be < default')
		return false
	}
	
	// Conservative should have longer initial delay
	if conservative_config.initial_delay <= default_config.initial_delay {
		println('  Failed: Conservative initial_delay should be > default')
		return false
	}
	
	// Conservative should have longer max delay
	if conservative_config.max_delay <= default_config.max_delay {
		println('  Failed: Conservative max_delay should be > default')
		return false
	}
	
	// Conservative should have larger multiplier
	if conservative_config.multiplier <= default_config.multiplier {
		println('  Failed: Conservative multiplier should be > default')
		return false
	}
	
	return true
}


// ============================================================================
// Property 9.9: Delay is Non-Negative
// For any retry configuration and attempt, delay should never be negative
// Validates: Requirements 9.1
// ============================================================================
fn test_property_9_9_delay_non_negative() bool {
	for _ in 0 .. test_iterations {
		// Test with various configurations including edge cases
		configs := [
			RetryConfig{
				max_retries: 5
				initial_delay: 1
				max_delay: 100
				multiplier: 1.1
				jitter: true
				jitter_factor: 0.5
			},
			RetryConfig{
				max_retries: 3
				initial_delay: 0
				max_delay: 1000
				multiplier: 2.0
				jitter: true
				jitter_factor: 0.25
			},
			RetryConfig{
				max_retries: 10
				initial_delay: 10000
				max_delay: 5000  // max_delay < initial_delay
				multiplier: 2.0
				jitter: true
				jitter_factor: 0.25
			},
		]
		
		for config in configs {
			executor := new_retry_executor(config)
			
			for attempt in 0 .. 10 {
				delay := executor.calculate_delay(attempt)
				
				if delay < 0 {
					println('  Failed: Delay ${delay} is negative at attempt ${attempt}')
					return false
				}
			}
		}
	}
	return true
}

// ============================================================================
// Property 9.10: First Attempt Has Initial Delay
// For any retry configuration without jitter, the first attempt (attempt 0)
// should have delay equal to initial_delay
// Validates: Requirements 9.1
// ============================================================================
fn test_property_9_10_first_attempt_delay() bool {
	for _ in 0 .. test_iterations {
		initial_delay := generate_random_int(100, 5000)
		
		config := RetryConfig{
			max_retries: 5
			initial_delay: initial_delay
			max_delay: 60000
			multiplier: 2.0
			jitter: false
			jitter_factor: 0.0
		}
		
		executor := new_retry_executor(config)
		first_delay := executor.calculate_delay(0)
		
		// First attempt delay should equal initial_delay (multiplier^0 = 1)
		if first_delay != initial_delay {
			println('  Failed: First attempt delay ${first_delay} != initial_delay ${initial_delay}')
			return false
		}
	}
	return true
}

fn main() {
	println('🚀 开始 Retry Mechanism 属性测试...')
	println('Feature: v-hono-upload-integration, Property 9: Retry Mechanism')
	println('Validates: Requirements 9.1, 9.2, 9.3')
	println('每个属性测试运行 ${test_iterations} 次迭代\n')

	rand.seed([u32(time.now().unix()), u32(98765)])

	mut stats := PropertyTestStats{}

	// Run property tests
	stats.run_property_test('Property 9.1: Exponential Backoff Delay Calculation', test_property_9_1_exponential_backoff)
	stats.run_property_test('Property 9.2: Delay Increases with Each Attempt', test_property_9_2_delay_increases)
	stats.run_property_test('Property 9.3: Max Delay is Respected', test_property_9_3_max_delay_respected)
	stats.run_property_test('Property 9.4: Jitter Adds Randomness Within Bounds', test_property_9_4_jitter_within_bounds)
	stats.run_property_test('Property 9.5: Retry Count Configuration is Respected', test_property_9_5_retry_count_respected)
	stats.run_property_test('Property 9.6: Default Config Has Sensible Values', test_property_9_6_default_config_values)
	stats.run_property_test('Property 9.7: Aggressive Config Has Shorter Delays', test_property_9_7_aggressive_config)
	stats.run_property_test('Property 9.8: Conservative Config Has Longer Delays', test_property_9_8_conservative_config)
	stats.run_property_test('Property 9.9: Delay is Non-Negative', test_property_9_9_delay_non_negative)
	stats.run_property_test('Property 9.10: First Attempt Has Initial Delay', test_property_9_10_first_attempt_delay)

	// Print summary
	stats.print_summary()

	// Exit with error code if any tests failed
	if stats.failed_tests > 0 {
		exit(1)
	}
}