//! Does the mission runtime actually carry the tools we depend on?
//!
//! Every capability in this codebase is written twice: once as code that
//! invokes a binary, and once as a Dockerfile line that installs it. The two
//! are only connected by someone having built and shipped the image, and
//! nothing checked that they agreed.
//!
//! They did not. `deploy/clawmates-runtime/Dockerfile` gained a Rust
//! toolchain, `gitleaks`, `trivy`, `semgrep` and `cargo-audit`; the image was
//! never built, and gw-04 kept running the previous one for days. The
//! consequences were all silent:
//!
//!   - `verify_tests` could not launch `cargo test`, so every `on_green_tests`
//!     phase landed on `-wip` — indistinguishable from "no test suite here"
//!   - `security_scan` emitted `tool_error` rows and reported completion
//!   - the evaluator's allow-listed checks could not run the scanners
//!
//! No error, no log line, no failing test. The code was right and the machine
//! was not. This module makes that specific disagreement observable: it asks
//! the running container what it has and says so plainly at boot.
//!
//! It is a report, not a gate. A missing scanner should not stop the server
//! from serving — it should stop us believing a scan that scanned nothing.

use crate::container_exec;
use bollard::Docker;
use std::time::Duration;

const PROBE_TIMEOUT: Duration = Duration::from_secs(20);

/// A tool the platform invokes inside the runtime container, and what breaks
/// without it. The consequence text is the point: a bare list of missing
/// binaries does not tell an operator what is now quietly not happening.
struct Dependency {
    argv: &'static [&'static str],
    needed_for: &'static str,
}

const DEPENDENCIES: &[Dependency] = &[
    Dependency {
        argv: &["zeroclaw", "--version"],
        needed_for: "driving every container-tier turn; the version is also how \
                     a runtime image that silently rolled back is noticed",
    },
    Dependency {
        argv: &["cargo", "--version"],
        needed_for: "the on_green_tests gate for Rust repos; without it every \
                     phase is unverified and lands on -wip",
    },
    Dependency {
        argv: &["git", "--version"],
        needed_for: "agent-side git operations in the mission checkout",
    },
    Dependency {
        argv: &["gitleaks", "version"],
        needed_for: "secret scanning in security_scan phases and evaluator checks",
    },
    Dependency {
        argv: &["trivy", "--version"],
        needed_for: "vulnerability scanning in security_scan phases",
    },
    Dependency {
        argv: &["semgrep", "--version"],
        needed_for: "static analysis in security_scan phases",
    },
    Dependency {
        argv: &["cargo-audit", "--version"],
        needed_for: "dependency advisories in security_scan phases",
    },
];

/// One tool's availability, as reported by the container itself.
pub struct ToolStatus {
    pub program: String,
    pub present: bool,
    /// Version string when present, error when not.
    pub detail: String,
    pub needed_for: &'static str,
}

/// Probe the runtime container for everything we invoke inside it.
///
/// Returns an empty vec if Docker itself is unreachable — that is a different
/// and louder failure which the caller reports separately, and emitting six
/// "missing" lines for it would be misleading.
pub async fn probe(container: &str) -> Result<Vec<ToolStatus>, String> {
    let docker = container_exec::connect().map_err(|e| format!("docker unreachable: {e}"))?;
    let mut out = Vec::with_capacity(DEPENDENCIES.len());
    for dep in DEPENDENCIES {
        let argv: Vec<String> = dep.argv.iter().map(|s| s.to_string()).collect();
        let status =
            match container_exec::exec(&docker, container, None, &argv, PROBE_TIMEOUT).await {
                Ok(r) if r.success() => ToolStatus {
                    program: dep.argv[0].to_string(),
                    present: true,
                    detail: r
                        .combined()
                        .lines()
                        .next()
                        .unwrap_or("")
                        .trim()
                        .chars()
                        .take(80)
                        .collect(),
                    needed_for: dep.needed_for,
                },
                Ok(r) => ToolStatus {
                    program: dep.argv[0].to_string(),
                    present: false,
                    detail: r.combined().trim().chars().take(160).collect(),
                    needed_for: dep.needed_for,
                },
                Err(e) => ToolStatus {
                    program: dep.argv[0].to_string(),
                    present: false,
                    detail: e.chars().take(160).collect(),
                    needed_for: dep.needed_for,
                },
            };
        out.push(status);
    }
    out.push(probe_mission_uid_can_write(&docker, container).await);
    Ok(out)
}

/// Can uid 65532 actually work in the missions tree?
///
/// `container_exec` now runs every mission exec as 65532 rather than root, so
/// that no phase leaves behind files the cleanup (which runs as 65532) cannot
/// delete. That only holds while the image gives 65532 a writable `HOME` and
/// `CARGO_HOME` — and in the deployed image its default `HOME`
/// (`/zeroclaw-data`) and `/usr/local/cargo` are BOTH root-owned, which is why
/// `container_exec::mission_env` redirects them into the missions root.
///
/// If a future image moves that mount or tightens its permissions, every cargo
/// invocation starts failing for a reason no error message would connect to a
/// uid. So it is probed at boot, alongside the tools, and reported the same way.
async fn probe_mission_uid_can_write(docker: &Docker, container: &str) -> ToolStatus {
    let root = crate::mission_workspace::missions_root();
    let probe = root.join("_probe-uid");
    // Through `exec`, not `exec_as_root`: the point is to exercise the exact
    // policy real mission work gets, including the env it is given.
    let argv: Vec<String> = [
        "sh",
        "-c",
        &format!(
            "set -e; mkdir -p \"$HOME\" \"$CARGO_HOME\" {p};              : > {p}/w; rm -rf {p}; echo \"uid=$(id -u) HOME=$HOME CARGO_HOME=$CARGO_HOME\"",
            p = probe.display()
        ),
    ]
    .iter()
    .map(|s| s.to_string())
    .collect();

    let detail = match container_exec::exec(
        docker,
        container,
        Some(&root.display().to_string()),
        &argv,
        PROBE_TIMEOUT,
    )
    .await
    {
        Ok(r) if r.success() => {
            return ToolStatus {
                program: "mission-uid".to_string(),
                present: true,
                detail: r.combined().trim().chars().take(120).collect(),
                needed_for: "every mission exec, so no phase leaves root-owned files",
            }
        }
        Ok(r) => r.combined().trim().chars().take(160).collect(),
        Err(e) => e.chars().take(160).collect(),
    };
    ToolStatus {
        program: "mission-uid".to_string(),
        present: false,
        detail,
        needed_for: "every mission exec, so no phase leaves root-owned files",
    }
}

/// Probe at startup and write the result to stderr.
///
/// Spawned rather than awaited so a slow or absent Docker socket cannot delay
/// the server coming up — the report is diagnostic, and the platform has to
/// keep working without it.
pub fn report_at_boot() {
    tokio::spawn(async {
        let container = std::env::var("CLAWMATES_RUNTIME_CONTAINER")
            .unwrap_or_else(|_| "clawmates-runtime".to_string());
        match probe(&container).await {
            Err(e) => eprintln!(
                "runtime_preflight: could not probe `{container}` ({e}) — mission \
                 test gating and security scans may silently do nothing"
            ),
            Ok(tools) => {
                let missing: Vec<&ToolStatus> = tools.iter().filter(|t| !t.present).collect();
                if missing.is_empty() {
                    let names: Vec<&str> = tools.iter().map(|t| t.program.as_str()).collect();
                    // The VERSIONS, not just the names. A tag that quietly
                    // points at an older build passes a presence check
                    // perfectly: gw-04's default tag was two zeroclaw releases
                    // behind while every probe said "present", and the only way
                    // anyone found out was running the binary by hand.
                    let detail: Vec<String> = tools
                        .iter()
                        .map(|t| format!("{}={}", t.program, t.detail))
                        .collect();
                    eprintln!(
                        "runtime_preflight: `{container}` has all {} expected tools ({}) — {}",
                        tools.len(),
                        names.join(", "),
                        detail.join("; ")
                    );
                    return;
                }
                eprintln!(
                    "runtime_preflight: `{container}` is MISSING {} of {} tools the \
                     platform invokes. The image on this host is behind \
                     deploy/clawmates-runtime/Dockerfile — rebuild and redeploy it.",
                    missing.len(),
                    tools.len()
                );
                for t in missing {
                    eprintln!(
                        "runtime_preflight:   {} — absent. Disables: {}. ({})",
                        t.program, t.needed_for, t.detail
                    );
                }
            }
        }
    });
}

#[cfg(test)]
mod tests {
    use super::*;

    /// Every dependency must be probed with a flag that exits zero and prints
    /// a version. A typo here produces a permanent false "missing" that would
    /// train an operator to ignore the report — worse than no report at all.
    #[test]
    fn every_dependency_probe_is_a_version_query() {
        for dep in DEPENDENCIES {
            assert!(
                dep.argv.len() >= 2,
                "{} needs an argument that exits 0",
                dep.argv[0]
            );
            let flag = dep.argv[1];
            assert!(
                flag == "--version" || flag == "version",
                "{} probes with `{flag}`, which may not exit 0",
                dep.argv[0]
            );
            assert!(
                !dep.needed_for.is_empty(),
                "{} must say what breaks without it",
                dep.argv[0]
            );
        }
    }
}