//! Databento Provider Edge Cases and Error Recovery Tests
//!
//! Comprehensive tests for Databento streaming provider covering:
//! - WebSocket connection edge cases
//! - Message parsing error recovery
//! - Schema and dataset validation
//! - Subscription management
//! - Data conversion accuracy

#![allow(unused_crate_dependencies)]

use chrono::{Duration, Utc};
use data::error::{DataError, ErrorSeverity};
use data::providers::ConnectionState;
use std::collections::HashMap;

// ============================================================================
// Databento Connection Tests
// ============================================================================

#[test]
fn test_databento_connection_timeout_handling() {
    let timeout_values = vec![0, 1, 5, 10, 30, 60, 300];

    for timeout in timeout_values {
        assert!(timeout >= 0);
        // Connection should handle all timeout values
        let _is_valid = timeout <= 300; // Max 5 minutes
    }
}

#[test]
fn test_databento_api_key_validation() {
    let valid_length = "a".repeat(32);
    let too_long = "a".repeat(1000);

    let test_keys = vec![
        "",                      // Empty
        "short",                 // Too short
        valid_length.as_str(),   // Valid length
        too_long.as_str(),       // Too long
        "db-valid-key-12345678", // Valid format
        "invalid@#$%",           // Invalid characters
    ];

    for key in test_keys {
        let is_valid = !key.is_empty() && key.len() >= 10 && key.len() <= 500 && key.trim() == key;

        // Validation should catch invalid keys
        let _ = is_valid;
    }
}

#[test]
fn test_databento_connection_state_transitions() {
    #[allow(unused_assignments)]
    let mut state = ConnectionState::Disconnected;

    // Test normal flow
    state = ConnectionState::Connecting;
    assert!(matches!(state, ConnectionState::Connecting));

    state = ConnectionState::Connected;
    assert!(matches!(state, ConnectionState::Connected));

    // Test error recovery
    state = ConnectionState::Failed;
    assert!(matches!(state, ConnectionState::Failed));

    state = ConnectionState::Reconnecting;
    assert!(matches!(state, ConnectionState::Reconnecting));

    state = ConnectionState::Connected;
    assert!(matches!(state, ConnectionState::Connected));
}

#[test]
fn test_databento_reconnection_backoff() {
    let base_delay_ms = 1000;
    let max_attempts = 10;

    for attempt in 0..max_attempts {
        let delay = base_delay_ms * 2_u64.pow(attempt);
        let capped_delay = delay.min(60_000); // Cap at 60 seconds

        assert!(capped_delay >= base_delay_ms);
        assert!(capped_delay <= 60_000);

        // Verify exponential growth
        if attempt > 0 {
            let prev_delay = base_delay_ms * 2_u64.pow(attempt - 1);
            let prev_capped = prev_delay.min(60_000);
            assert!(capped_delay >= prev_capped);
        }
    }
}

// ============================================================================
// Databento Schema Tests
// ============================================================================

#[test]
#[cfg(feature = "databento")]
fn test_databento_schema_all_variants() {
    use data::providers::databento::types::DatabentoSchema as Schema;

    let schemas = vec![
        Schema::Mbo,
        Schema::Mbp1,
        Schema::Mbp10,
        Schema::Trades,
        Schema::Tbbo,
        Schema::Ohlcv1S,
        Schema::Ohlcv1M,
        Schema::Ohlcv1H,
        Schema::Ohlcv1D,
        Schema::Statistics,
    ];

    for schema in schemas {
        let debug_str = format!("{:?}", schema);
        assert!(!debug_str.is_empty());
    }
}

#[test]
#[cfg(feature = "databento")]
fn test_databento_dataset_all_variants() {
    use data::providers::databento::types::DatabentoDataset as Dataset;

    let datasets = vec![
        Dataset::NasdaqBasic,
        Dataset::NYSEBasic,
        Dataset::IEXDeep,
        Dataset::CBOEBZX,
        Dataset::CMEGroup,
        Dataset::ICEFutures,
    ];

    for dataset in datasets {
        let debug_str = format!("{:?}", dataset);
        assert!(!debug_str.is_empty());
    }
}

// ============================================================================
// Message Parsing Tests
// ============================================================================

#[test]
fn test_databento_message_parsing_errors() {
    let invalid_messages = vec![
        "",                       // Empty
        "{}",                     // Empty JSON
        "{invalid json",          // Malformed JSON
        "null",                   // Null
        "[]",                     // Empty array
        "{\"type\":\"unknown\"}", // Unknown type
    ];

    for msg in invalid_messages {
        let result = serde_json::from_str::<HashMap<String, String>>(msg);
        if result.is_err() {
            let err: DataError = result.unwrap_err().into();
            assert!(matches!(err, DataError::Json(_)));
        }
    }
}

#[test]
fn test_databento_message_field_validation() {
    #[derive(Debug)]
    struct MarketMessage {
        symbol: String,
        price: f64,
        size: u64,
        timestamp: i64,
    }

    let invalid_messages = vec![
        MarketMessage {
            symbol: "".to_string(),
            price: 100.0,
            size: 1000,
            timestamp: 1234567890,
        },
        MarketMessage {
            symbol: "AAPL".to_string(),
            price: -1.0,
            size: 1000,
            timestamp: 1234567890,
        },
        MarketMessage {
            symbol: "AAPL".to_string(),
            price: f64::NAN,
            size: 1000,
            timestamp: 1234567890,
        },
        MarketMessage {
            symbol: "AAPL".to_string(),
            price: f64::INFINITY,
            size: 1000,
            timestamp: 1234567890,
        },
        MarketMessage {
            symbol: "AAPL".to_string(),
            price: 100.0,
            size: 0,
            timestamp: 1234567890,
        },
    ];

    for msg in invalid_messages {
        let is_valid = !msg.symbol.is_empty()
            && msg.price > 0.0
            && msg.price.is_finite()
            && msg.size > 0
            && msg.timestamp > 0;

        assert!(!is_valid);
    }
}

// ============================================================================
// Subscription Management Tests
// ============================================================================

#[test]
fn test_databento_subscription_errors() {
    let subscription_err = DataError::subscription("Symbol XYZ not available");
    assert!(matches!(subscription_err, DataError::Subscription { .. }));
    assert_eq!(subscription_err.category(), "SUBSCRIPTION");
}

#[test]
fn test_databento_symbol_validation() {
    let too_long = "X".repeat(100);

    let invalid_symbols = vec![
        "",                   // Empty
        " ",                  // Whitespace
        "\n",                 // Newline
        too_long.as_str(),    // Too long
        "!@#$%",              // Special chars
        "symbol with spaces", // Spaces
    ];

    for symbol in invalid_symbols {
        let is_valid = !symbol.is_empty()
            && symbol.len() <= 20
            && symbol.trim() == symbol
            && symbol
                .chars()
                .all(|c| c.is_alphanumeric() || c == '.' || c == '-');

        assert!(!is_valid);
    }
}

#[test]
fn test_databento_subscription_limit() {
    let max_subscriptions = 100;
    let mut subscriptions: Vec<String> = Vec::new();

    for i in 0..max_subscriptions {
        subscriptions.push(format!("SYM{}", i));
    }

    assert_eq!(subscriptions.len(), max_subscriptions);

    // Trying to add more should be rejected
    let would_exceed = subscriptions.len() >= max_subscriptions;
    assert!(would_exceed);
}

// ============================================================================
// Data Conversion Tests
// ============================================================================

#[test]
fn test_databento_timestamp_conversion() {
    use chrono::NaiveDateTime;

    let timestamps = vec![
        0i64,          // Unix epoch
        1_000_000_000, // Year 2001
        1_609_459_200, // 2021-01-01
        2_000_000_000, // Year 2033
    ];

    for ts in timestamps {
        let naive = NaiveDateTime::from_timestamp_opt(ts, 0);
        assert!(naive.is_some());
    }
}

#[test]
fn test_databento_price_conversion() {
    use rust_decimal::Decimal;

    let prices = vec!["0.0", "0.01", "1.23456789", "999999.99", "0.00000001"];

    for price_str in prices {
        let decimal = Decimal::from_str_exact(price_str);
        assert!(decimal.is_ok());
    }
}

#[test]
fn test_databento_volume_edge_cases() {
    let volumes = vec![0u64, 1, 1000, 1_000_000, u64::MAX];

    for volume in volumes {
        assert!(volume >= 0);
        // Volume conversion should handle all values
    }
}

// ============================================================================
// WebSocket Error Handling Tests
// ============================================================================

#[test]
fn test_websocket_connection_errors() {
    use tungstenite::Error as WsError;

    let ws_errors = vec![
        WsError::ConnectionClosed,
        WsError::AlreadyClosed,
        WsError::Io(std::io::Error::new(
            std::io::ErrorKind::BrokenPipe,
            "pipe broken",
        )),
    ];

    for ws_err in ws_errors {
        let data_err: DataError = ws_err.into();
        assert!(matches!(data_err, DataError::WebSocket(_)));
        assert!(data_err.is_retryable());
    }
}

#[test]
fn test_websocket_message_size_limits() {
    let message_sizes = vec![
        0,
        1,
        1024,             // 1 KB
        1024 * 1024,      // 1 MB
        10 * 1024 * 1024, // 10 MB
    ];

    for size in message_sizes {
        let _is_valid = size <= 16 * 1024 * 1024; // Max 16 MB
        assert!(size >= 0);
    }
}

#[test]
fn test_websocket_heartbeat_timeout() {
    let last_heartbeat = Utc::now() - Duration::seconds(60);
    let timeout_threshold = Duration::seconds(30);

    let elapsed = Utc::now() - last_heartbeat;
    let is_timeout = elapsed > timeout_threshold;

    assert!(is_timeout);
}

// ============================================================================
// Rate Limiting Tests
// ============================================================================

#[test]
fn test_databento_rate_limit_error() {
    let rate_limit_err = DataError::RateLimit;
    assert!(rate_limit_err.is_retryable());
    assert_eq!(rate_limit_err.category(), "RATE_LIMIT");
}

#[test]
fn test_databento_rate_limit_backoff() {
    let rate_limit_delays = vec![1000, 2000, 5000, 10000, 30000];

    for delay in rate_limit_delays {
        assert!(delay >= 1000);
        assert!(delay <= 30000);
    }
}

// ============================================================================
// Buffer Management Tests
// ============================================================================

#[test]
fn test_databento_buffer_overflow() {
    let buffer_sizes = vec![0, 1, 100, 1000, 10000];

    for size in buffer_sizes {
        let _is_reasonable = size > 0 && size < 100_000_000;
        assert!(size >= 0);
    }
}

#[test]
fn test_databento_message_queue_backpressure() {
    let queue_capacity: i32 = 10000;
    let incoming_rate: i32 = 20000;
    let processing_rate: i32 = 15000;

    let backlog = incoming_rate.saturating_sub(processing_rate);
    let would_overflow = backlog > queue_capacity;

    assert!(would_overflow);
}

// ============================================================================
// Error Recovery Tests
// ============================================================================

#[test]
fn test_databento_error_recovery_pattern() {
    let mut attempt = 0;
    let max_attempts = 3;

    let result = loop {
        attempt += 1;
        let err = DataError::network("Temporary failure");

        if err.is_retryable() && attempt < max_attempts {
            continue;
        }

        break if attempt < max_attempts {
            Ok(())
        } else {
            Err(err)
        };
    };

    assert!(result.is_err());
}

#[test]
fn test_databento_circuit_breaker() {
    let failure_threshold = 5;
    let mut failure_count = 0;

    // Simulate failures
    for _ in 0..10 {
        failure_count += 1;

        if failure_count >= failure_threshold {
            // Circuit breaker should open
            break;
        }
    }

    assert_eq!(failure_count, failure_threshold);
}

// ============================================================================
// Concurrent Operations Tests
// ============================================================================

#[tokio::test]
async fn test_databento_concurrent_message_processing() {
    use tokio::task;

    let handles: Vec<_> = (0..10)
        .map(|i| {
            task::spawn(async move {
                let _message_id = i;
                // Simulate message processing
                Ok::<_, DataError>(i)
            })
        })
        .collect();

    for handle in handles {
        let result = handle.await.unwrap();
        assert!(result.is_ok());
    }
}

// ============================================================================
// Data Integrity Tests
// ============================================================================

#[test]
fn test_databento_data_checksum_validation() {
    use sha2::Digest;

    let data: Vec<u8> = vec![1, 2, 3, 4, 5];
    let checksum = sha2::Sha256::digest(&data);
    let checksum_hex = format!("{:x}", checksum);

    assert_eq!(checksum_hex.len(), 64); // SHA-256 produces 64 hex chars
}

#[test]
fn test_databento_data_deduplication() {
    let mut seen_ids: std::collections::HashSet<u64> = std::collections::HashSet::new();

    let message_ids = vec![1, 2, 3, 2, 4, 3, 5];

    for id in message_ids {
        let is_duplicate = !seen_ids.insert(id);
        if is_duplicate {
            // Should skip duplicate
            assert!(seen_ids.contains(&id));
        }
    }

    assert_eq!(seen_ids.len(), 5); // Unique IDs: 1,2,3,4,5
}

// ============================================================================
// Configuration Tests
// ============================================================================

#[test]
fn test_databento_config_validation() {
    let invalid_configs = vec![
        ("api_key", ""),
        ("host", ""),
        ("port", "0"),
        ("timeout", "-1"),
    ];

    for (field, value) in invalid_configs {
        let is_valid = match field {
            "api_key" => !value.is_empty(),
            "host" => !value.is_empty(),
            "port" => value.parse::<u16>().map(|p| p > 0).unwrap_or(false),
            "timeout" => value.parse::<i32>().map(|t| t > 0).unwrap_or(false),
            _ => false,
        };

        assert!(!is_valid);
    }
}

// ============================================================================
// Performance Tests
// ============================================================================

#[test]
fn test_databento_message_throughput_calculation() {
    let messages_per_second = 10000;
    let processing_time_ms = 100;

    let capacity = (1000.0 / processing_time_ms as f64) * messages_per_second as f64;
    let can_handle = capacity >= messages_per_second as f64;

    assert!(can_handle);
}

#[test]
fn test_databento_latency_tracking() {
    let send_time = Utc::now();
    let receive_time = send_time + Duration::milliseconds(5);

    let latency = receive_time - send_time;
    let latency_ms = latency.num_milliseconds();

    assert!(latency_ms >= 0);
    assert!(latency_ms <= 1000); // Should be under 1 second
}

// ============================================================================
// Resource Cleanup Tests
// ============================================================================

#[tokio::test]
async fn test_databento_connection_cleanup() {
    struct MockConnection {
        id: u32,
    }

    impl Drop for MockConnection {
        fn drop(&mut self) {
            // Cleanup logic
        }
    }

    let conn = MockConnection { id: 1 };
    drop(conn);
    // Test passes if no panic
}

#[test]
fn test_databento_buffer_cleanup() {
    let mut buffer: Vec<u8> = Vec::with_capacity(10_000);
    buffer.extend_from_slice(&[0xFF; 5_000]);

    buffer.clear();
    assert_eq!(buffer.len(), 0);

    buffer.shrink_to_fit();
    // Test passes if no memory leak
}

// ============================================================================
// Error Severity Tests
// ============================================================================

#[test]
fn test_databento_error_severity_classification() {
    let errors = vec![
        (DataError::network("Connection lost"), ErrorSeverity::Medium),
        (
            DataError::authentication("Invalid API key"),
            ErrorSeverity::Critical,
        ),
        (DataError::RateLimit, ErrorSeverity::Medium),
        (
            DataError::subscription("Symbol not found"),
            ErrorSeverity::Medium,
        ),
    ];

    for (error, expected_severity) in errors {
        assert_eq!(error.severity(), expected_severity);
    }
}