use anyhow::Result;
use tracing::info;

use crate::Router;

/// The OpenWrt package name for the TollGate reference implementation.
const TOLLGATE_PACKAGE: &str = "tollgate-module-basic-go";

/// Direct-download fallback URLs by opkg architecture string.
/// Used when the package is not in any configured feed.
/// Source: https://github.com/OpenTollGate/tollgate-module-basic-go/releases/tag/v0.2.0
fn ipk_url(arch: &str) -> Option<&'static str> {
    match arch {
        "mips_24kc"          => Some("https://github.com/OpenTollGate/tollgate-module-basic-go/releases/download/v0.2.0/mips_24kc.ipk"),
        "mipsel_24kc"        => Some("https://github.com/OpenTollGate/tollgate-module-basic-go/releases/download/v0.2.0/mipsel_24kc.ipk"),
        "aarch64_cortex-a53" => Some("https://github.com/OpenTollGate/tollgate-module-basic-go/releases/download/v0.2.0/aarch64_cortex-a53.ipk"),
        "aarch64_cortex-a72" => Some("https://github.com/OpenTollGate/tollgate-module-basic-go/releases/download/v0.2.0/aarch64_cortex-a72.ipk"),
        "arm_cortex-a7"      => Some("https://github.com/OpenTollGate/tollgate-module-basic-go/releases/download/v0.2.0/arm_cortex-a7.ipk"),
        _ => None,
    }
}

/// Install tollgate-module-basic-go.
///
/// Tries opkg first (works if a custom feed is configured). Falls back to
/// downloading the .ipk directly from GitHub releases if opkg can't find it.
/// Caller is responsible for running `opkg_update` first.
pub fn install_tollgate(router: &Router) -> Result<()> {
    info!("[{}] Installing {}", router.host, TOLLGATE_PACKAGE);

    // Fast path: standard opkg install (or already installed).
    if router.opkg_install(TOLLGATE_PACKAGE).is_ok() {
        return Ok(());
    }

    // Package not in any feed — download the .ipk directly.
    let arch = router
        .run_ok("opkg print-architecture | grep -v 'all\\|noarch' | tail -1 | awk '{print $2}'")?;
    let arch = arch.trim();

    let url = ipk_url(arch).ok_or_else(|| {
        anyhow::anyhow!(
            "No pre-built TollGate package for architecture '{}'. \
             Add a custom opkg feed or build from source.",
            arch
        )
    })?;

    info!("[{}] Downloading TollGate for {} from GitHub releases", router.host, arch);
    router.run_ok(&format!("wget -O /tmp/tollgate.ipk '{}'", url))?;

    // Capture stderr too — BusyBox opkg exits 0 even on "Cannot install" failures.
    let (out, _code) = router.run("opkg install --force-depends /tmp/tollgate.ipk 2>&1")?;
    router.run_ok("rm -f /tmp/tollgate.ipk")?;

    if out.contains("Cannot install") || out.contains("errors encountered") {
        if out.contains("Only have") && out.contains("available on filesystem") {
            // Extract the sizes from the error for a user-readable message.
            // Example: "Only have 8884kb available on filesystem /overlay, pkg tollgate-wrt needs 18750"
            anyhow::bail!(
                "No space left on router for TollGate ({}). \
                 This router has insufficient flash storage. \
                 Consider a router with ≥32 MB flash or add an extroot USB drive.",
                out.lines()
                    .find(|l| l.contains("Only have"))
                    .unwrap_or("check router disk space")
                    .trim()
            );
        }
        anyhow::bail!("TollGate installation failed: {}", out.trim());
    }

    Ok(())
}