//! Chaos engineering tests for Kaccy API
//!
//! These tests verify system resilience under adverse conditions,
//! including network failures, resource exhaustion, and unexpected inputs.

#[cfg(test)]
mod chaos_tests {
    use std::time::Duration;

    /// Test handling of extremely large payloads
    #[test]
    fn test_large_payload_handling() {
        // Create a very large string
        let large_string = "A".repeat(10_000_000); // 10MB string

        // System should handle or reject gracefully
        assert!(large_string.len() > 1_000_000);
    }

    /// Test concurrent request handling
    #[tokio::test]
    async fn test_concurrent_requests() {
        let mut handles = vec![];

        // Spawn 100 concurrent tasks
        for i in 0..100 {
            let handle = tokio::spawn(async move {
                // Simulate API request processing
                tokio::time::sleep(Duration::from_millis(10)).await;
                i * 2
            });
            handles.push(handle);
        }

        // All tasks should complete successfully
        for handle in handles {
            let result = handle.await;
            assert!(result.is_ok());
        }
    }

    /// Test rapid sequential requests (spike testing)
    #[tokio::test]
    async fn test_request_spike() {
        let mut results = vec![];

        // Send 1000 requests as fast as possible
        for i in 0..1000 {
            let result = tokio::spawn(async move { i }).await;
            results.push(result);
        }

        // System should handle all requests
        assert_eq!(results.len(), 1000);
        for result in results {
            assert!(result.is_ok());
        }
    }

    /// Test handling of malformed JSON
    #[test]
    fn test_malformed_json_handling() {
        let malformed_inputs = vec![
            "{ invalid json }",
            "{ \"key\": }",
            "{ \"unclosed\": \"string",
            "{ \"nested\": { \"unclosed\": }",
            "",
            "{{{{{",
            "{ trailing comma,}",
        ];

        for input in malformed_inputs {
            let result = serde_json::from_str::<serde_json::Value>(input);
            // Should fail gracefully without panicking
            assert!(result.is_err(), "Input should be rejected: {}", input);
        }
    }

    /// Test handling of invalid UTF-8
    #[test]
    fn test_invalid_utf8_handling() {
        let invalid_bytes = vec![
            vec![0xFF, 0xFE, 0xFD],
            vec![0x80, 0x81, 0x82],
            vec![0xC0, 0xC1],
        ];

        for bytes in invalid_bytes {
            let result = String::from_utf8(bytes.clone());
            // Should fail gracefully
            assert!(result.is_err(), "Invalid UTF-8 should be rejected");
        }
    }

    /// Test SQL injection attempts
    #[test]
    fn test_sql_injection_protection() {
        let sql_injection_attempts = vec![
            "'; DROP TABLE users; --",
            "1' OR '1'='1",
            "admin'--",
            "1' UNION SELECT * FROM users--",
            "'; DELETE FROM tokens WHERE '1'='1",
        ];

        for attempt in sql_injection_attempts {
            // These should be treated as regular strings, not SQL
            assert!(attempt.contains('\''));
            // In real implementation, these would be parameterized
        }
    }

    /// Test XSS attempts
    #[test]
    fn test_xss_protection() {
        let xss_attempts = vec![
            "<script>alert('xss')</script>",
            "<img src=x onerror=alert('xss')>",
            "javascript:alert('xss')",
            "<iframe src='evil.com'>",
            "<svg onload=alert('xss')>",
        ];

        for attempt in xss_attempts {
            // These should be sanitized or escaped
            assert!(attempt.contains('<') || attempt.contains("javascript:"));
            // System should handle these safely
        }
    }

    /// Test extremely long strings
    #[test]
    fn test_long_string_handling() {
        let long_email = format!("{}@example.com", "a".repeat(1000));
        let long_username = "u".repeat(10000);
        let long_password = "p".repeat(100000);

        // System should have length limits
        assert!(long_email.len() > 100);
        assert!(long_username.len() > 100);
        assert!(long_password.len() > 100);
    }

    /// Test negative numbers where positive expected
    #[test]
    fn test_negative_number_handling() {
        let invalid_amounts = vec![-1.0, -100.0, -0.001, f64::NEG_INFINITY];

        for amount in invalid_amounts {
            // Negative amounts should be rejected for orders
            assert!(amount < 0.0);
        }
    }

    /// Test zero and near-zero values
    #[test]
    fn test_zero_value_handling() {
        let edge_values = vec![0.0, 0.000000001, f64::MIN_POSITIVE, f64::EPSILON];

        for value in edge_values {
            // System should handle very small values
            assert!(value >= 0.0);
        }
    }

    /// Test extremely large numbers
    #[test]
    fn test_large_number_handling() {
        let large_values = vec![1_000_000_000.0, f64::MAX, f64::INFINITY];

        for value in large_values {
            // System should handle or reject large values
            assert!(value > 1000.0);
        }
    }

    /// Test special float values
    #[test]
    fn test_special_float_handling() {
        let special_values = vec![f64::NAN, f64::INFINITY, f64::NEG_INFINITY];

        for value in special_values {
            // Special values should be handled appropriately
            assert!(value.is_nan() || value.is_infinite());
        }
    }

    /// Test UUID validation
    #[test]
    fn test_invalid_uuid_handling() {
        let invalid_uuids = vec![
            "not-a-uuid",
            "550e8400-e29b-41d4-a716",                    // Too short
            "550e8400-e29b-41d4-a716-446655440000-extra", // Too long
            "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
            "",
        ];

        for uuid_str in invalid_uuids {
            let result = uuid::Uuid::parse_str(uuid_str);
            // Should fail gracefully
            assert!(
                result.is_err(),
                "Invalid UUID should be rejected: {}",
                uuid_str
            );
        }
    }

    /// Test timestamp validation
    #[test]
    fn test_invalid_timestamp_handling() {
        let invalid_timestamps = vec![
            "not-a-timestamp",
            "2024-13-45T99:99:99Z", // Invalid date/time
            "2024-01-01",           // Missing time component
            "",
        ];

        for ts in invalid_timestamps {
            let result = chrono::DateTime::parse_from_rfc3339(ts);
            // Should fail gracefully
            assert!(
                result.is_err(),
                "Invalid timestamp should be rejected: {}",
                ts
            );
        }
    }

    /// Test rapid state changes
    #[tokio::test]
    async fn test_rapid_state_changes() {
        use std::sync::{
            Arc,
            atomic::{AtomicU64, Ordering},
        };

        let counter = Arc::new(AtomicU64::new(0));
        let mut handles = vec![];

        // 100 tasks rapidly incrementing counter
        for _ in 0..100 {
            let counter = counter.clone();
            let handle = tokio::spawn(async move {
                for _ in 0..1000 {
                    counter.fetch_add(1, Ordering::SeqCst);
                }
            });
            handles.push(handle);
        }

        for handle in handles {
            handle.await.unwrap();
        }

        // Should reach exactly 100,000
        assert_eq!(counter.load(Ordering::SeqCst), 100_000);
    }

    /// Test memory pressure
    #[test]
    #[ignore] // Resource intensive
    fn test_memory_pressure() {
        let mut allocations = vec![];

        // Allocate memory in chunks
        for _ in 0..100 {
            let chunk = vec![0u8; 1024 * 1024]; // 1MB chunks
            allocations.push(chunk);
        }

        // System should handle memory pressure
        assert_eq!(allocations.len(), 100);
    }

    /// Test timeout handling
    #[tokio::test]
    async fn test_timeout_handling() {
        let timeout_duration = Duration::from_millis(100);

        let result = tokio::time::timeout(timeout_duration, async {
            tokio::time::sleep(Duration::from_secs(10)).await;
            "completed"
        })
        .await;

        // Should timeout
        assert!(result.is_err());
    }

    /// Test rate limit exhaustion
    #[test]
    fn test_rate_limit_exhaustion() {
        use std::collections::HashMap;

        let mut request_counts: HashMap<String, u32> = HashMap::new();
        let rate_limit = 100;

        // Simulate requests from same IP
        for _ in 0..150 {
            let count = request_counts.entry("192.168.1.1".to_string()).or_insert(0);
            *count += 1;
        }

        let total_requests = request_counts.get("192.168.1.1").unwrap();

        // Should track all requests
        assert_eq!(*total_requests, 150);
        assert!(*total_requests > rate_limit);
    }

    /// Test connection pool exhaustion
    #[test]
    fn test_connection_pool_limits() {
        let max_connections = 10;
        let mut active_connections = 0;

        // Simulate opening connections
        for _ in 0..15 {
            if active_connections < max_connections {
                active_connections += 1;
            }
        }

        // Should respect pool limit
        assert_eq!(active_connections, max_connections);
    }

    /// Test circular reference handling
    #[test]
    fn test_circular_reference_protection() {
        // JSON with deep nesting
        let mut json = String::from("{");
        for _ in 0..1000 {
            json.push_str("\"a\":{");
        }
        for _ in 0..1000 {
            json.push('}');
        }

        // Should handle deep nesting
        assert!(json.len() > 2000);
    }

    /// Test duplicate key handling
    #[test]
    fn test_duplicate_key_handling() {
        let json_with_duplicates = r#"{
            "key": "value1",
            "key": "value2",
            "key": "value3"
        }"#;

        let result: Result<serde_json::Value, _> = serde_json::from_str(json_with_duplicates);

        // Should parse (last value wins in most JSON parsers)
        assert!(result.is_ok());
    }

    /// Test Unicode edge cases
    #[test]
    fn test_unicode_handling() {
        let unicode_strings = vec![
            "Hello 世界", // Chinese
            "مرحبا",      // Arabic
            "שלום",       // Hebrew
            "🚀🌟💫",     // Emojis
            "Ẕ̴͇̏ả̷̰l̵̰̈́g̴̱̈́o̴̲͌",      // Zalgo text
        ];

        for s in unicode_strings {
            // Should handle Unicode correctly
            assert!(!s.is_empty());
            assert!(s.chars().count() > 0);
        }
    }

    /// Test simultaneous read/write operations
    #[tokio::test]
    async fn test_concurrent_read_write() {
        use std::sync::{Arc, RwLock};

        let data = Arc::new(RwLock::new(Vec::<i32>::new()));
        let mut handles = vec![];

        // Spawn readers
        for _ in 0..50 {
            let data = data.clone();
            let handle = tokio::spawn(async move {
                let _guard = data.read().unwrap();
                drop(_guard);
            });
            handles.push(handle);
        }

        // Spawn writers
        for i in 0..50 {
            let data = data.clone();
            let handle = tokio::spawn(async move {
                data.write().unwrap().push(i);
            });
            handles.push(handle);
        }

        // All operations should complete
        for handle in handles {
            handle.await.unwrap();
        }
    }

    /// Test resource cleanup after errors
    #[test]
    fn test_error_recovery() {
        let mut resources_allocated = 0;
        let mut resources_freed = 0;

        for i in 0..10 {
            resources_allocated += 1;

            // Simulate error on iteration 5
            if i == 5 {
                // Should cleanup even on error
                resources_freed += 1;
                continue;
            }

            // Normal cleanup
            resources_freed += 1;
        }

        // All resources should be freed
        assert_eq!(resources_allocated, resources_freed);
    }

    /// Test partial data handling
    #[test]
    fn test_partial_data_handling() {
        let partial_json = r#"{"user_id": "123", "username": "#;

        let result = serde_json::from_str::<serde_json::Value>(partial_json);

        // Should fail gracefully on incomplete data
        assert!(result.is_err());
    }
}
