//! Controle de modo (managed/monitor) e canal via `iw`.
//!
//! Isso é uma ponte deliberada: o protocolo real é nl80211 por netlink, e
//! trocar este módulo por uma implementação nativa (sem depender do binário
//! `iw` instalado) é o próximo passo natural. Por ora, `iw` é amplamente
//! disponível, testado e evita reimplementar genl/nl80211 antes de validar
//! o resto do pipeline com o adaptador real.

use crate::error::{Result, SabiaError};
use crate::iface::Mode;
use std::process::Command;

fn run(cmd: &str, args: &[&str]) -> Result<String> {
    let out = Command::new(cmd).args(args).output().map_err(|e| SabiaError::CommandFailed {
        cmd: format!("{cmd} {}", args.join(" ")),
        detail: e.to_string(),
    })?;
    if !out.status.success() {
        let detail = String::from_utf8_lossy(&out.stderr).trim().to_string();
        let detail = if detail.is_empty() {
            String::from_utf8_lossy(&out.stdout).trim().to_string()
        } else {
            detail
        };
        if detail.contains("Operation not permitted") || detail.contains("nl80211 not found") {
            return Err(SabiaError::PermissionDenied);
        }
        return Err(SabiaError::CommandFailed {
            cmd: format!("{cmd} {}", args.join(" ")),
            detail,
        });
    }
    Ok(String::from_utf8_lossy(&out.stdout).into_owned())
}

pub fn iw_dev_type(iface: &str) -> Option<Mode> {
    let out = run("iw", &["dev", iface, "info"]).ok()?;
    for line in out.lines() {
        let line = line.trim();
        if let Some(t) = line.strip_prefix("type ") {
            return Some(match t.trim() {
                "monitor" => Mode::Monitor,
                "managed" => Mode::Managed,
                _ => Mode::Unknown,
            });
        }
    }
    None
}

/// Lista (canal, frequência) suportados pelo phy da interface.
pub fn supported_channels(iface: &str) -> Result<Vec<u32>> {
    let out = run("iw", &["dev", iface, "info"])?;
    let phy = out
        .lines()
        .find_map(|l| l.trim().strip_prefix("wiphy "))
        .map(|n| format!("phy{n}"))
        .ok_or_else(|| SabiaError::CommandFailed {
            cmd: "iw dev info".into(),
            detail: "wiphy não encontrado na saída".into(),
        })?;
    let info = run("iw", &["phy", &phy, "info"])?;
    let mut channels = Vec::new();
    for line in info.lines() {
        let line = line.trim();
        // formato: "* 2412 MHz [1] (20.0 dBm)"
        if let Some(rest) = line.strip_prefix("* ") {
            if let Some(start) = rest.find('[') {
                if let Some(end) = rest[start..].find(']') {
                    if let Ok(ch) = rest[start + 1..start + end].parse::<u32>() {
                        channels.push(ch);
                    }
                }
            }
        }
    }
    channels.sort_unstable();
    channels.dedup();
    Ok(channels)
}

/// Põe a interface em modo monitor. Requer `CAP_NET_ADMIN` (normalmente root).
pub fn set_monitor_mode(iface: &str, enable: bool) -> Result<()> {
    run("ip", &["link", "set", iface, "down"])?;
    let target = if enable { "monitor" } else { "managed" };
    run("iw", &["dev", iface, "set", "type", target])?;
    run("ip", &["link", "set", iface, "up"])?;
    Ok(())
}

/// Troca o canal atual da interface (precisa já estar em modo monitor).
pub fn set_channel(iface: &str, channel: u32) -> Result<()> {
    run("iw", &["dev", iface, "set", "channel", &channel.to_string()])?;
    Ok(())
}