// network/platform/windows/interface_stats.rs - Windows IP Helper API interface stats

use crate::network::interface_stats::{InterfaceStats, InterfaceStatsProvider};
use std::collections::HashMap;
use std::io;
use std::time::SystemTime;

#[cfg(target_os = "windows")]
use windows::Win32::NetworkManagement::IpHelper::{FreeMibTable, GetIfTable2, MIB_IF_TABLE2};
#[cfg(target_os = "windows")]
use windows::Win32::NetworkManagement::Ndis::IfOperStatusUp;

/// Windows-specific implementation using IP Helper API
pub struct WindowsStatsProvider;

impl InterfaceStatsProvider for WindowsStatsProvider {
    #[cfg(target_os = "windows")]
    fn get_all_stats(&self) -> Result<Vec<InterfaceStats>, io::Error> {
        unsafe {
            let mut table: *mut MIB_IF_TABLE2 = std::ptr::null_mut();

            let result = GetIfTable2(&mut table);
            if result.is_err() {
                return Err(io::Error::other(format!(
                    "GetIfTable2 failed with error code: {:?}",
                    result
                )));
            }

            let table_ref = match table.as_ref() {
                Some(t) => t,
                None => return Err(io::Error::other("Failed to get interface table")),
            };

            let num_entries = table_ref.NumEntries as usize;
            // Use LUID as key for deduplication since it's unique per interface
            let mut stats_map: HashMap<u64, InterfaceStats> = HashMap::new();

            for i in 0..num_entries {
                let row = &*table_ref.Table.as_ptr().add(i);

                // Convert interface alias (friendly name) to string
                let name = String::from_utf16_lossy(&row.Alias)
                    .trim_end_matches('\0')
                    .to_string();

                if name.is_empty() {
                    continue;
                }

                // Skip virtual/filter interfaces by name patterns
                // These are NDIS filter drivers, WFP filters, and virtual adapters
                // Always skip these as they just mirror the physical interface
                let name_lower = name.to_lowercase();
                if name_lower.contains("-npcap")
                    || name_lower.contains("-wfp")
                    || name_lower.contains("-qos")
                    || name_lower.contains("-native")
                    || name_lower.contains("-virtual")
                    || name_lower.contains("-packet")
                    || name_lower.contains("lightweight filter")
                    || name_lower.contains("mac layer")
                {
                    continue;
                }

                // Skip "Local Area Con" with zero traffic (these are usually disconnected adapters)
                let total_traffic =
                    row.InOctets + row.OutOctets + row.InUcastPkts + row.OutUcastPkts;
                if name_lower.starts_with("local area con") && total_traffic == 0 {
                    continue;
                }

                // Skip interfaces that are not operationally up
                // But allow them if they have any traffic statistics
                let has_traffic = row.InOctets > 0 || row.OutOctets > 0;
                if row.OperStatus != IfOperStatusUp && !has_traffic {
                    continue;
                }

                let stat = InterfaceStats {
                    interface_name: name.clone(),
                    rx_bytes: row.InOctets,
                    tx_bytes: row.OutOctets,
                    rx_packets: row.InUcastPkts + row.InNUcastPkts,
                    tx_packets: row.OutUcastPkts + row.OutNUcastPkts,
                    rx_errors: row.InErrors,
                    tx_errors: row.OutErrors,
                    rx_dropped: row.InDiscards,
                    tx_dropped: row.OutDiscards,
                    collisions: 0, // Not available on modern Windows interfaces
                    timestamp: SystemTime::now(),
                };

                // Use InterfaceLuid.Value as unique key to prevent duplicates
                // This ensures each physical interface appears only once
                let luid_value = row.InterfaceLuid.Value;
                stats_map.insert(luid_value, stat);
            }

            FreeMibTable(table.cast());

            let stats_vec: Vec<InterfaceStats> = stats_map.into_values().collect();
            log::debug!(
                "Windows interface stats collected: {} interfaces",
                stats_vec.len()
            );
            for stat in &stats_vec {
                log::debug!(
                    "  {} - RX: {} bytes, TX: {} bytes",
                    stat.interface_name,
                    stat.rx_bytes,
                    stat.tx_bytes
                );
            }

            Ok(stats_vec)
        }
    }

    #[cfg(not(target_os = "windows"))]
    fn get_all_stats(&self) -> Result<Vec<InterfaceStats>, io::Error> {
        Err(io::Error::new(
            io::ErrorKind::Unsupported,
            "Windows interface stats not available on this platform",
        ))
    }
}

#[cfg(test)]
#[cfg(target_os = "windows")]
mod tests {
    use super::*;

    #[test]
    fn test_windows_list_interfaces() {
        let provider = WindowsStatsProvider;
        let result = provider.get_all_stats();

        match result {
            Ok(stats) => {
                assert!(!stats.is_empty(), "Expected at least one interface");
            }
            Err(e) => {
                panic!("Failed to list interfaces: {:?}", e);
            }
        }
    }

    #[test]
    fn test_windows_get_all_stats() {
        let provider = WindowsStatsProvider;
        let result = provider.get_all_stats();

        match result {
            Ok(stats) => {
                assert!(!stats.is_empty(), "Expected at least one interface");
                for stat in stats {
                    assert!(!stat.interface_name.is_empty());
                }
            }
            Err(e) => {
                panic!("Failed to get stats: {:?}", e);
            }
        }
    }
}