//! Journal-read endpoints for the dashboard.
//!
//! `GET /api/journal/{name}` reads a managed agent container's journal, OR
//! one of the four hive infra services (`hive-ci`, `hive-forge`,
//! `hive-gateway`, `hive-matrix` — [`hive_priv_sock::InfraContainer`] is the
//! allowlist). A container's journal is a `journalctl -M` read, delegated
//! to the root helper since entering a machine needs privileges hive-c0re
//! doesn't have; `hive-gateway` is nginx on the host, so it reads host
//! journald filtered to that unit and needs no helper at all.
//! `GET /api/journal-host` reads host-side journald, both gated by an
//! allow-list of known units so arbitrary unit names can't be probed.
//! Operator-only by virtue of the dashboard binding host-only.

use axum::{
    extract::Path as AxumPath,
    http::StatusCode,
    response::{IntoResponse, Response},
};
use serde::Deserialize;
use utoipa::IntoParams;

use problem_details::ProblemDetails;

use super::{Ident, error_problem, strip_container_prefix};
use crate::lifecycle;

#[derive(Deserialize, IntoParams)]
pub(super) struct JournalQuery {
    /// Optional systemd unit filter — e.g. `hive-agent.service`. When
    /// omitted, returns the full machine journal.
    #[serde(default)]
    unit: Option<String>,
    /// Number of trailing lines to return. Capped at 5000.
    #[serde(default)]
    lines: Option<u32>,
}

/// Read `journalctl -M <container> -b` and return its text output.
///
/// Operator-only by virtue of the dashboard being host-bound. hive-c0re
/// runs unprivileged (privsep), so the `-M` read — which enters the
/// container namespace and needs root — is delegated to hive-priv.
///
/// `name` is either a managed agent name (`iris`, optionally already
/// carrying the `h-` prefix) or one of the four infra names (`hive-ci` /
/// `hive-forge` / `hive-gateway` / `hive-matrix` — see
/// [`hive_priv_sock::InfraContainer`]). Infra targets don't run the
/// per-agent hive daemons, so `unit` is ignored for them — the whole
/// machine journal, or for the gateway the host journal filtered to its
/// own unit.
#[utoipa::path(
    get,
    path = "/api/journal/{name}",
    params(
        ("name" = String, Path, description = "agent name, or one of the four infra container names"),
        JournalQuery,
    ),
    responses(
        (status = 200, description = "journal text", body = String, content_type = "text/plain"),
        (status = 400, description = "bad agent name or unknown unit"),
        (status = 404, description = "no such managed container"),
    ),
    tag = "journal"
)]
pub(super) async fn get_journal(
    AxumPath(name): AxumPath<String>,
    axum::extract::Query(q): axum::extract::Query<JournalQuery>,
) -> Result<Response, ProblemDetails> {
    let lines = q.lines.unwrap_or(500).min(5000);

    if let Ok(infra) = name.parse::<hive_priv_sock::InfraContainer>() {
        return match infra.target() {
            hive_priv_sock::InfraTarget::Container(machine) => {
                read_journal_response(machine, None, lines).await
            }
            // No machine to enter — the gateway's nginx is a host unit, so
            // this is a plain host-journal read filtered to it. `-M` is
            // what needed root here, not journalctl itself.
            hive_priv_sock::InfraTarget::HostUnit(unit) => {
                read_host_journal_response(Some(unit), lines).await
            }
        };
    }

    // Defense-in-depth format check so weird chars never reach the
    // shellout below — the `lifecycle::list()` existence check would
    // catch them anyway, but rejecting at the boundary keeps the
    // failure mode crisp.
    let name = match Ident::parse(&name) {
        Ok(n) => n,
        Err(reason) => {
            return Err(ProblemDetails::from_status_code(StatusCode::BAD_REQUEST)
                .with_detail(format!("bad agent name: {reason}")));
        }
    };
    // Validate the container name against the list of managed
    // containers so we don't shell out with arbitrary input.
    let container = strip_container_prefix(name.as_str());
    let prefixed = format!("{}{container}", lifecycle::AGENT_PREFIX);
    let live = lifecycle::list().await.unwrap_or_default();
    if !live.iter().any(|c| c == &prefixed) {
        return Err(ProblemDetails::from_status_code(StatusCode::NOT_FOUND)
            .with_detail(format!("journal: no managed container {prefixed:?}")));
    }
    let unit = match q.unit.as_deref().filter(|s| !s.is_empty()) {
        Some(u) => {
            // accept any of the per-container hive daemons [.service] —
            // anything else refused.
            let allowed = [
                "hive-agent.service",
                "hive-mcp-http.service",
                "hive-bash-daemon.service",
                "hive-matrix-daemon.service",
            ];
            let unit = if u.ends_with(".service") {
                u.to_owned()
            } else {
                format!("{u}.service")
            };
            if !allowed.contains(&unit.as_str()) {
                return Err(ProblemDetails::from_status_code(StatusCode::BAD_REQUEST)
                    .with_detail(format!("journal: unknown unit {unit:?}")));
            }
            Some(unit)
        }
        None => None,
    };
    read_journal_response(&prefixed, unit, lines).await
}

/// Shared `journalctl -M <machine> [-u <unit>]` shellout + response
/// formatting for [`get_journal`], factored out so the infra-container
/// branch (no `unit` filtering) and the agent-container branch (allow-listed
/// `unit` filtering) don't duplicate the priv-client call + stdout/stderr
/// combining.
async fn read_journal_response(
    machine: &str,
    unit: Option<String>,
    lines: u32,
) -> Result<Response, ProblemDetails> {
    match crate::priv_client::read_container_journal(
        machine,
        hive_priv_sock::JournalQuery {
            lines,
            boot: true,
            output: hive_priv_sock::JournalOutput::ShortIso,
            unit,
            ..Default::default()
        },
    )
    .await
    {
        Ok((stdout, stderr)) => {
            // Combine stdout + stderr — journalctl emits to both on errors.
            let mut body = stdout;
            if !stderr.is_empty() {
                body.push_str("\n--- stderr ---\n");
                body.push_str(&stderr);
            }
            Ok(([("content-type", "text/plain; charset=utf-8")], body).into_response())
        }
        Err(e) => Err(error_problem(&format!("journal read: {e:#}"))),
    }
}

#[derive(Deserialize, IntoParams)]
pub(super) struct JournalHostQuery {
    /// Service unit name to filter to. If omitted, returns all logs.
    #[serde(default)]
    unit: Option<String>,
    /// Number of trailing lines. Capped at 5000. Default 500.
    #[serde(default)]
    lines: Option<u32>,
}

/// Host-side journald (no
/// `-M` container flag).
///
/// Restricted to an allow-list of known host services so arbitrary unit
/// names can't be probed. Operator-only by virtue of the dashboard binding
/// to a host-only port.
#[utoipa::path(
    get,
    path = "/api/journal-host",
    params(JournalHostQuery),
    responses(
        (status = 200, description = "journal text", body = String, content_type = "text/plain"),
        (status = 400, description = "unknown unit"),
    ),
    tag = "journal"
)]
pub(super) async fn get_journal_host(
    axum::extract::Query(q): axum::extract::Query<JournalHostQuery>,
) -> Result<Response, ProblemDetails> {
    let lines = q.lines.unwrap_or(500).min(5000);
    // `nginx.service` is the gateway — its logs are host-side.
    let allowed = ["hive-c0re.service", "hive-priv.service", "nginx.service"];
    let unit = match q.unit.as_deref().filter(|s| !s.is_empty()) {
        Some(u) => {
            let unit = if u.ends_with(".service") {
                u.to_owned()
            } else {
                format!("{u}.service")
            };
            if !allowed.contains(&unit.as_str()) {
                return Err(ProblemDetails::from_status_code(StatusCode::BAD_REQUEST)
                    .with_detail(format!("journal-host: unknown unit {unit:?}")));
            }
            Some(unit)
        }
        None => None,
    };
    read_host_journal_response(unit.as_deref(), lines).await
}

/// `journalctl [-u <unit>]` on the host + response formatting. No `-M`, so
/// no root and no priv-client hop — hive-c0re reads host journald directly.
///
/// ⚠️ `unit` is trusted by the time it gets here: [`get_journal_host`]
/// allow-lists an operator-supplied one, and [`get_journal`] passes a unit
/// that came from the [`hive_priv_sock::InfraContainer`] enum. Don't hand
/// this a raw query parameter.
async fn read_host_journal_response(
    unit: Option<&str>,
    lines: u32,
) -> Result<Response, ProblemDetails> {
    let mut cmd = tokio::process::Command::new("journalctl");
    cmd.args(["--no-pager", "--output=short-iso", "--lines"])
        .arg(lines.to_string());
    if let Some(u) = unit {
        cmd.args(["-u", u]);
    }
    match cmd.output().await {
        Ok(out) => {
            let mut body = String::from_utf8_lossy(&out.stdout).into_owned();
            if !out.status.success() {
                body.push_str("\n--- stderr ---\n");
                body.push_str(&String::from_utf8_lossy(&out.stderr));
            }
            Ok(([("content-type", "text/plain; charset=utf-8")], body).into_response())
        }
        Err(e) => Err(error_problem(&format!("journalctl spawn: {e}"))),
    }
}