use crate::{config::Config, docker, firewall, netns::build_transport, swap, traffic, wg};

use std::{
    collections::BTreeMap,
    fs,
    process::Command,
    time::{SystemTime, UNIX_EPOCH},
};

const ONLINE_HANDSHAKE_THRESHOLD_SECS: u64 = 180;

pub fn print_status(cfg: &Config) -> anyhow::Result<()> {
    println!("System:");
    let svc = Command::new("systemctl")
        .args(["is-active", "awg2-harness"])
        .output();
    match svc {
        Ok(out) if out.status.success() => println!("  service: active"),
        Ok(_) => println!("  service: inactive"),
        Err(_) => println!("  service: unknown"),
    }

    let target = match docker::discover_target(cfg) {
        Ok(t) => t,
        Err(e) => {
            println!("  container: not available ({e})");
            println!("  container_id: n/a");
            println!("  pid: n/a");
            println!("  netns: n/a");
            println!("  interface: n/a");
            print_degraded_sections(cfg)?;
            return Ok(());
        }
    };

    println!("  container: {}", target.container_name);
    println!("  container_id: {}", target.container_id);
    println!("  pid: {}", target.container_pid);
    println!("  netns: {}", target.netns_path);
    println!("  interface: {}", target.interface_name);

    let docker_path_diag = docker::collect_port_path_diagnostics(
        &target.container_name,
        cfg.host_firewall.amnezia_port,
    );

    let peers = wg::discover_peers(
        target.container_pid,
        &target.container_name,
        &cfg.amnezia.peer_ipv4_cidr,
    )?;
    println!("Peers:");
    println!("  total: {}", peers.len());
    for p in peers {
        println!("  - {}", p.ipv4);
    }

    println!("WireGuard clients:");
    println!(
        "  IP          State    Latest handshake    RX        TX        Public key                                    Endpoint"
    );
    match wg::discover_peer_runtime(
        target.container_pid,
        &target.container_name,
        &cfg.amnezia.peer_ipv4_cidr,
    ) {
        Ok(runtime_peers) => {
            let mut by_ip: BTreeMap<String, &wg::PeerRuntime> = BTreeMap::new();
            for rp in &runtime_peers {
                for ip in &rp.allowed_ips {
                    by_ip.insert(ip.clone(), rp);
                }
            }

            let peers_sorted = wg::discover_peers(
                target.container_pid,
                &target.container_name,
                &cfg.amnezia.peer_ipv4_cidr,
            )?;
            for p in peers_sorted {
                let ip = p.ipv4.to_string();
                if let Some(rp) = by_ip.get(&ip) {
                    let state = handshake_is_online(
                        rp.latest_handshake_epoch,
                        ONLINE_HANDSHAKE_THRESHOLD_SECS,
                    );
                    let hs = format_handshake_age(rp.latest_handshake_epoch);
                    let rx = format_bytes(rp.transfer_rx_bytes.unwrap_or(0));
                    let tx = format_bytes(rp.transfer_tx_bytes.unwrap_or(0));
                    let ep = rp.endpoint.clone().unwrap_or_else(|| "-".to_string());
                    println!(
                        "  {:<11} {:<8} {:<19} {:<9} {:<9} {:<44} {}",
                        ip, state, hs, rx, tx, rp.public_key, ep
                    );
                } else {
                    println!(
                        "  {:<11} {:<8} {:<19} {:<9} {:<9} {:<44} -",
                        ip, "offline", "never", "0B", "0B", "-"
                    );
                }
            }
        }
        Err(e) => println!("  unavailable ({e})"),
    }

    println!("Traffic desired:");
    println!("  peer_limit: {}", cfg.traffic.peer_limit);
    println!("  root_rate: {}", cfg.traffic.root_rate);
    println!("  ifb_name: {}", cfg.traffic.ifb_name);
    println!("  class_start_id: {}", cfg.traffic.class_start_id);

    println!("Traffic actual:");
    match traffic::inspect_drift_summary(cfg) {
        Ok(None) => println!("  drift: no"),
        Ok(Some(reason)) => {
            println!("  drift: yes");
            println!("  reason: {}", reason);
        }
        Err(e) => println!("  drift: unknown ({e})"),
    }

    println!("  topology:");
    let transport = build_transport(target.container_pid, &target.container_name);
    let egress_qdisc = transport
        .run(&["tc", "qdisc", "show", "dev", &target.interface_name])
        .unwrap_or_default();
    let ingress_qdisc = egress_qdisc.clone();
    let ifb_qdisc = transport
        .run(&["tc", "qdisc", "show", "dev", &cfg.traffic.ifb_name])
        .unwrap_or_default();
    println!("    egress_htb_present: {}", egress_qdisc.contains("htb"));
    println!("    ingress_present: {}", ingress_qdisc.contains("ingress"));
    println!("    ifb_htb_present: {}", ifb_qdisc.contains("htb"));

    println!("  peer_table:");
    match traffic::peer_status_table(cfg) {
        Ok(Some(rows)) if rows.is_empty() => println!("    no peers discovered"),
        Ok(Some(rows)) => {
            for r in rows {
                println!(
                    "    ip={} class_id={} egress_filter={} ingress_filter={} egress={}/{} ingress={}/{} drift={}",
                    r.ip,
                    r.class_id,
                    r.egress_filter_present,
                    r.ingress_filter_present,
                    r.egress_rate.unwrap_or_else(|| "n/a".to_string()),
                    r.egress_ceil.unwrap_or_else(|| "n/a".to_string()),
                    r.ingress_rate.unwrap_or_else(|| "n/a".to_string()),
                    r.ingress_ceil.unwrap_or_else(|| "n/a".to_string()),
                    r.drift_reason.unwrap_or_else(|| "no".to_string())
                );
            }
        }
        Ok(None) => println!("    traffic disabled"),
        Err(e) => println!("    unavailable ({e})"),
    }

    println!("Peer traffic counters:");
    println!("  IP          Egress hits    Ingress hits");
    match collect_peer_filter_hits(
        &target.interface_name,
        &cfg.traffic.ifb_name,
        target.container_pid,
        &target.container_name,
    ) {
        Ok(map) if map.is_empty() => println!("  filter statistics: unavailable"),
        Ok(map) => {
            for (ip, (eg, ing)) in map {
                println!("  {:<11} {:<13} {}", ip, eg, ing);
            }
        }
        Err(_) => println!("  filter statistics: unavailable"),
    }

    println!("Host firewall:");
    println!("  enabled: {}", cfg.host_firewall.enabled);
    println!("  ssh_port: {}/tcp", cfg.host_firewall.ssh_port);
    println!(
        "  amnezia_port: {}/{}",
        cfg.host_firewall.amnezia_port,
        cfg.host_firewall.amnezia_protocols.join(",")
    );
    println!(
        "  input_policy: {}",
        cfg.host_firewall
            .default_input_policy
            .trim()
            .to_ascii_lowercase()
    );
    if cfg.host_firewall.enabled {
        match firewall::host_firewall_drift_reason(cfg) {
            Ok(None) => println!("  drift: no"),
            Ok(Some(reason)) => {
                println!("  drift: yes");
                println!("  reason: {}", reason);
            }
            Err(e) => println!("  drift: unknown ({e})"),
        }
    }

    print_docker_amnezia_port_path(&docker_path_diag);

    println!("Anti-torrent:");
    println!("  enabled: {}", cfg.anti_torrent.enabled);
    println!(
        "  max_connections_per_peer: {}",
        cfg.anti_torrent.max_connections_per_peer
    );

    if cfg.anti_torrent.enabled {
        match firewall::antitorrent_drift_reason(cfg) {
            Ok(None) => println!("  drift: no"),
            Ok(Some(reason)) => {
                println!("  drift: yes");
                println!("  reason: {}", reason);
            }
            Err(e) => println!("  drift: unknown ({e})"),
        }
        match firewall::antitorrent_drop_counter(cfg) {
            Ok(Some((packets, bytes))) => {
                println!("  dropped_packets: {}", packets);
                println!("  dropped_bytes: {}", bytes);
            }
            Ok(None) => println!("  dropped_packets: n/a"),
            Err(e) => println!("  dropped_packets: inspect error ({e})"),
        }
    }

    print_swap_status(cfg);

    let ct_count = Command::new("sysctl")
        .args(["-n", "net.netfilter.nf_conntrack_count"])
        .output()
        .ok()
        .map(|o| String::from_utf8_lossy(&o.stdout).trim().to_string())
        .unwrap_or_else(|| "n/a".to_string());
    let ct_max = Command::new("sysctl")
        .args(["-n", "net.netfilter.nf_conntrack_max"])
        .output()
        .ok()
        .map(|o| String::from_utf8_lossy(&o.stdout).trim().to_string())
        .unwrap_or_else(|| "n/a".to_string());
    println!("Conntrack:");
    println!("  nf_conntrack_count: {}", ct_count);
    println!("  nf_conntrack_max: {}", ct_max);

    println!("Last actions:");
    let last = fs::read_to_string("/run/awg2-harness/last_action.state").unwrap_or_default();
    if last.trim().is_empty() {
        println!("  no persisted state");
    } else {
        for line in last.lines() {
            println!("  {}", line);
        }
    }

    println!("Recent events:");
    let events = fs::read_to_string("/run/awg2-harness/events.log").unwrap_or_default();
    let lines: Vec<&str> = events.lines().collect();
    if lines.is_empty() {
        println!("  no recent events");
    } else {
        for l in lines.iter().rev().take(10).rev() {
            println!("  {l}");
        }
    }

    print_reboot_section(cfg);

    Ok(())
}

fn print_degraded_sections(cfg: &Config) -> anyhow::Result<()> {
    println!("Peers:");
    println!("  unavailable (container/netns not discovered)");

    println!("WireGuard clients:");
    println!("  unavailable (container/netns not discovered)");

    println!("Traffic desired:");
    println!("  peer_limit: {}", cfg.traffic.peer_limit);
    println!("  root_rate: {}", cfg.traffic.root_rate);
    println!("  ifb_name: {}", cfg.traffic.ifb_name);
    println!("  class_start_id: {}", cfg.traffic.class_start_id);

    println!("Traffic actual:");
    println!("  drift: unknown (container/netns not discovered)");

    println!("Host firewall:");
    println!("  enabled: {}", cfg.host_firewall.enabled);
    println!("  ssh_port: {}/tcp", cfg.host_firewall.ssh_port);
    println!(
        "  amnezia_port: {}/{}",
        cfg.host_firewall.amnezia_port,
        cfg.host_firewall.amnezia_protocols.join(",")
    );
    println!(
        "  input_policy: {}",
        cfg.host_firewall
            .default_input_policy
            .trim()
            .to_ascii_lowercase()
    );
    if cfg.host_firewall.enabled {
        match firewall::host_firewall_drift_reason(cfg) {
            Ok(None) => println!("  drift: no"),
            Ok(Some(reason)) => {
                println!("  drift: yes");
                println!("  reason: {}", reason);
            }
            Err(e) => println!("  drift: unknown ({e})"),
        }
    }

    println!("Docker/Amnezia port path:");
    println!("  docker_userland_proxy: unknown");
    println!("  published_udp_port: unknown");
    println!("  host_forward_policy_drop: unknown");
    println!("  docker_forward_rules_present: unknown");
    println!("  note: FORWARD is Docker-managed; awg2-harness does not modify host FORWARD");

    println!("Anti-torrent:");
    println!("  enabled: {}", cfg.anti_torrent.enabled);
    println!(
        "  max_connections_per_peer: {}",
        cfg.anti_torrent.max_connections_per_peer
    );
    if cfg.anti_torrent.enabled {
        match firewall::antitorrent_drift_reason(cfg) {
            Ok(None) => println!("  drift: no"),
            Ok(Some(reason)) => {
                println!("  drift: yes");
                println!("  reason: {}", reason);
            }
            Err(e) => println!("  drift: unknown ({e})"),
        }
        match firewall::antitorrent_drop_counter(cfg) {
            Ok(Some((packets, bytes))) => {
                println!("  dropped_packets: {}", packets);
                println!("  dropped_bytes: {}", bytes);
            }
            Ok(None) => println!("  dropped_packets: n/a"),
            Err(e) => println!("  dropped_packets: inspect error ({e})"),
        }
    }

    print_swap_status(cfg);

    println!("Conntrack:");
    let ct_count = Command::new("sysctl")
        .args(["-n", "net.netfilter.nf_conntrack_count"])
        .output()
        .ok()
        .map(|o| String::from_utf8_lossy(&o.stdout).trim().to_string())
        .unwrap_or_else(|| "n/a".to_string());
    let ct_max = Command::new("sysctl")
        .args(["-n", "net.netfilter.nf_conntrack_max"])
        .output()
        .ok()
        .map(|o| String::from_utf8_lossy(&o.stdout).trim().to_string())
        .unwrap_or_else(|| "n/a".to_string());
    println!("  nf_conntrack_count: {}", ct_count);
    println!("  nf_conntrack_max: {}", ct_max);

    println!("Last actions:");
    let last = fs::read_to_string("/run/awg2-harness/last_action.state").unwrap_or_default();
    if last.trim().is_empty() {
        println!("  no persisted state");
    } else {
        for line in last.lines() {
            println!("  {}", line);
        }
    }

    println!("Recent events:");
    let events = fs::read_to_string("/run/awg2-harness/events.log").unwrap_or_default();
    let lines: Vec<&str> = events.lines().collect();
    if lines.is_empty() {
        println!("  no recent events");
    } else {
        for l in lines.iter().rev().take(10).rev() {
            println!("  {l}");
        }
    }

    print_reboot_section(cfg);
    Ok(())
}

fn print_reboot_section(cfg: &Config) {
    println!("Reboot scheduler:");
    println!("  enabled: {}", cfg.reboot.enabled);
    println!("  window_start_utc: {}", cfg.reboot.window_start_utc);
    println!("  window_end_utc: {}", cfg.reboot.window_end_utc);
    let svc = Command::new("systemctl")
        .args(["is-active", "awg2-reboot-scheduler"])
        .output();
    match svc {
        Ok(out) if out.status.success() => println!("  service: active"),
        Ok(_) => println!("  service: inactive"),
        Err(_) => println!("  service: unknown"),
    }

    let plan = fs::read_to_string("/run/awg2-harness/reboot.plan").unwrap_or_default();
    if plan.trim().is_empty() {
        println!("  planned: n/a");
    } else {
        for line in plan.lines() {
            println!("  {}", line);
        }
    }
}

fn print_swap_status(cfg: &Config) {
    println!("Swap:");
    match swap::inspect_swap(cfg) {
        Ok(s) => {
            println!("  enabled: {}", s.enabled);
            println!("  desired_path: {}", s.desired_path.display());
            println!("  desired_size_mb: {}", cfg.swap.size_mb);
            println!("  desired_priority: {}", cfg.swap.priority);
            println!("  active_entries: {}", s.active_entries.len());
            println!(
                "  desired_active: {}",
                if s.desired_active { "yes" } else { "no" }
            );
            println!("  exclusive: {}", if s.exclusive { "yes" } else { "no" });
            println!(
                "  fstab_exclusive: {}",
                if s.fstab_exclusive { "yes" } else { "no" }
            );
            println!("  fstab_swap_entries: {}", s.fstab_swap_entries.len());
            println!(
                "  swappiness_current: {}",
                s.current_swappiness
                    .map(|v| v.to_string())
                    .unwrap_or_else(|| "n/a".to_string())
            );
            println!(
                "  swappiness_persisted: {}",
                s.persisted_swappiness
                    .map(|v| v.to_string())
                    .unwrap_or_else(|| "n/a".to_string())
            );
            if let Some(reason) = s.drift_reason {
                println!("  drift: yes");
                println!("  drift_reason: {}", reason);
            } else {
                println!("  drift: no");
            }
        }
        Err(e) => {
            println!("  enabled: {}", cfg.swap.enabled);
            println!("  desired_path: {}", cfg.swap.path);
            println!("  drift: unknown ({e})");
        }
    }
}

fn print_docker_amnezia_port_path(diag: &docker::PortPathDiagnostics) {
    println!("Docker/Amnezia port path:");
    println!(
        "  docker_userland_proxy: {}",
        diag.docker_userland_proxy.as_str()
    );
    match &diag.published_udp_port {
        Some(p) => println!(
            "  published_udp_port: {} -> {}:{}",
            p.host_port, p.container_ip, p.container_port
        ),
        None => println!("  published_udp_port: unknown"),
    }
    println!(
        "  host_forward_policy_drop: {}",
        diag.host_forward_policy_drop.as_str()
    );
    println!(
        "  docker_forward_rules_present: {}",
        diag.docker_forward_rules_present.as_str()
    );
    println!("  note: FORWARD is Docker-managed; awg2-harness does not modify host FORWARD");
    if let Some(w) = diag.warning() {
        println!("  warning: {w}");
    }
}

fn handshake_is_online(epoch: Option<u64>, threshold_secs: u64) -> &'static str {
    if let Some(ts) = epoch {
        let now = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .map(|d| d.as_secs())
            .unwrap_or(0);
        if now.saturating_sub(ts) <= threshold_secs {
            return "online";
        }
    }
    "offline"
}

fn format_handshake_age(epoch: Option<u64>) -> String {
    let Some(ts) = epoch else {
        return "never".to_string();
    };
    let now = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map(|d| d.as_secs())
        .unwrap_or(0);
    let age = now.saturating_sub(ts);
    format!("{}s ago", age)
}

fn format_bytes(v: u64) -> String {
    const KB: f64 = 1024.0;
    const MB: f64 = KB * 1024.0;
    const GB: f64 = MB * 1024.0;
    let b = v as f64;
    if b >= GB {
        format!("{:.1}GB", b / GB)
    } else if b >= MB {
        format!("{:.1}MB", b / MB)
    } else if b >= KB {
        format!("{:.1}KB", b / KB)
    } else {
        format!("{}B", v)
    }
}

fn collect_peer_filter_hits(
    iface: &str,
    ifb: &str,
    pid: u32,
    container_name: &str,
) -> anyhow::Result<BTreeMap<String, (u64, u64)>> {
    let transport = build_transport(pid, container_name);
    let egress = transport.run(&["tc", "-s", "filter", "show", "dev", iface, "parent", "1:"])?;
    let ingress = transport.run(&["tc", "-s", "filter", "show", "dev", ifb, "parent", "2:"])?;
    let egress_hits = parse_tc_filter_hits(&egress);
    let ingress_hits = parse_tc_filter_hits(&ingress);

    let mut out: BTreeMap<String, (u64, u64)> = BTreeMap::new();
    for (ip, c) in egress_hits {
        out.entry(ip).or_insert((0, 0)).0 = c;
    }
    for (ip, c) in ingress_hits {
        out.entry(ip).or_insert((0, 0)).1 = c;
    }
    Ok(out)
}

fn parse_tc_filter_hits(raw: &str) -> BTreeMap<String, u64> {
    let mut out = BTreeMap::new();
    let mut current_ip: Option<String> = None;
    for line in raw.lines() {
        let t = line.trim();

        if t.contains("match ") {
            current_ip = extract_tc_match_ip(t);
        }

        if t.starts_with("Sent ") {
            if let Some(ip) = current_ip.clone() {
                let hits = parse_sent_packets(t).unwrap_or(0);
                out.insert(ip, hits);
            }
        } else if (t.contains(" success ") || t.starts_with("success "))
            && let Some(ip) = current_ip.clone()
        {
            let hits = parse_success_packets(t).unwrap_or(0);
            out.insert(ip, hits);
        }
    }
    out
}

fn parse_sent_packets(line: &str) -> Option<u64> {
    let toks: Vec<&str> = line.split_whitespace().collect();
    if toks.len() >= 5 && toks[0] == "Sent" && toks[2] == "bytes" && toks[4] == "pkt" {
        return toks[3].parse::<u64>().ok();
    }
    None
}

fn parse_success_packets(line: &str) -> Option<u64> {
    let toks: Vec<&str> = line.split_whitespace().collect();
    let pos = toks.iter().position(|v| *v == "success")?;
    toks.get(pos + 1)?.parse::<u64>().ok()
}

fn extract_tc_match_ip(line: &str) -> Option<String> {
    let toks: Vec<&str> = line.split_whitespace().collect();
    let pos = toks.iter().position(|v| *v == "match")?;
    let match_val = *toks.get(pos + 1)?;
    let (hex, mask) = match_val.split_once('/')?;
    if !mask.eq_ignore_ascii_case("ffffffff") || hex.len() != 8 {
        return None;
    }
    let b1 = u8::from_str_radix(&hex[0..2], 16).ok()?;
    let b2 = u8::from_str_radix(&hex[2..4], 16).ok()?;
    let b3 = u8::from_str_radix(&hex[4..6], 16).ok()?;
    let b4 = u8::from_str_radix(&hex[6..8], 16).ok()?;
    Some(format!("{b1}.{b2}.{b3}.{b4}"))
}

#[cfg(test)]
mod tests {
    use super::{parse_sent_packets, parse_success_packets, parse_tc_filter_hits};

    #[test]
    fn parse_sent_pkt_counter() {
        let line = "Sent 12345 bytes 67 pkt (dropped 0, overlimits 0 requeues 0)";
        assert_eq!(parse_sent_packets(line), Some(67));
    }

    #[test]
    fn parse_success_counter() {
        let line = "match 0a080102/ffffffff at 16 success 42";
        assert_eq!(parse_success_packets(line), Some(42));
    }

    #[test]
    fn parse_tc_filter_hits_supports_sent_and_success() {
        let raw = r#"
filter parent 1: protocol ip pref 1 u32 chain 0
filter parent 1: protocol ip pref 1 u32 chain 0 fh 800: ht divisor 1
filter parent 1: protocol ip pref 1 u32 chain 0 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:10 not_in_hw
  match 0a080102/ffffffff at 16
    Sent 100 bytes 7 pkt (dropped 0, overlimits 0 requeues 0)
filter parent 1: protocol ip pref 1 u32 chain 0 fh 800::801 order 2049 key ht 800 bkt 0 flowid 1:11 not_in_hw
  match 0a080103/ffffffff at 16 success 9
"#;

        let map = parse_tc_filter_hits(raw);
        assert_eq!(map.get("10.8.1.2"), Some(&7));
        assert_eq!(map.get("10.8.1.3"), Some(&9));
    }
}