rusty-stack 0.3.0

//! Uninstall orchestrator — removes the Rusty-managed ML stack so a clean
//! reinstall is possible without manual purging.
//!
//! # Tenet (v0.3.0 remediation)
//!
//! "Reinstall functionality is currently broken and DOES NOT WORK. Rusty
//! uninstall AND force-reinstall options MUST be fully functional across shells
//! (fish, bash, zsh) AND across OS's (cross Linux distributions)."
//!
//! This module existed in v0.2.0 as dead primitives (`PackageManager::purge`,
//! `purge_component_packages`) that were never wired into a user-facing flow.
//! It is now a real `uninstall_stack()` reachable via `rusty uninstall`.
//!
//! # What it removes
//!
//! 1. Python ML packages (pip) installed by Rusty components.
//! 2. ROCm/amdgpu system packages via the detected package manager (apt/dnf/
//!    pacman/zypper) — cross-distro; skipped with `--keep-rocm`.
//! 3. `/opt/rocm` (sudo) — skipped with `--keep-rocm`.
//! 4. The env files Rusty wrote (`~/.mlstack_env`, the fish `conf.d` file) and
//!    the legacy `source ~/.mlstack_env` lines from `~/.bashrc` / `~/.zshrc` /
//!    `~/.config/fish/config.fish` (cross-shell).
//! 5. The installed-component registry (`~/.mlstack/installed.json`).
//!
//! Sudo steps shell out to `sudo` (the user authenticates); they are skipped
//! (with a warning) if not root and sudo is unavailable, so the command never
//! stalls on a hidden prompt.

use std::path::PathBuf;
use std::process::Command;

use crate::core::registry::InstalledComponentRegistry;
use crate::platform::environment::{
    command_on_path, mlstack_global_dir, resolve_canonical_python_bin, resolve_user_home,
};

/// ROCm/amdgpu system-package name candidates tried across distros. The package
/// manager ignores names that aren't installed.
const ROCM_SYSTEM_PACKAGES: &[&str] = &[
    "rocm-hip-sdk",
    "rocm-opencl-sdk",
    "rocm-core",
    "rocm-dev",
    "rocm-opencl-runtime",
    "amdgpu",
    "amdgpu-dkms",
];

/// Python ML packages Rusty installs (pip). Each uninstall is non-fatal.
const ML_PIP_PACKAGES: &[&str] = &[
    "torch",
    "torchvision",
    "torchaudio",
    "triton",
    "pytorch-triton-rocm",
    "pytorch-triton",
    "vllm",
    "deepspeed",
    "megatron-core",
    "bitsandbytes",
    "flash-attn",
    "flash_attn",
    "aiter",
    "onnxruntime",
    "onnxruntime-rocm",
    "migraphx",
    "mpi4py",
    "wandb",
    "xformers",
    "accelerate",
    "transformers",
];

/// Options for [`uninstall_stack`].
#[derive(Debug, Clone, Default)]
pub struct UninstallOptions {
    /// Keep ROCm/amdgpu system packages and `/opt/rocm` (only remove Python +
    /// env/registry). Useful when reinstalling just the Python stack.
    pub keep_rocm: bool,
    /// Skip the interactive confirmation prompt.
    pub yes: bool,
    /// Also remove the `~/.mlstack/` data root (logs, cache, global venv).
    /// Off by default — preserves logs/diagnostics across reinstalls.
    pub purge_mlstack_dir: bool,
}

/// A summary of what uninstall did.
#[derive(Debug, Clone, Default)]
pub struct UninstallReport {
    pub pip_uninstall_attempted: Vec<String>,
    pub system_packages_purged: bool,
    pub opt_rocm_removed: bool,
    pub env_files_removed: Vec<String>,
    pub sourcing_lines_stripped: Vec<String>,
    pub registry_cleared: bool,
    pub warnings: Vec<String>,
}

impl UninstallReport {
    fn note(&mut self, msg: impl Into<String>) {
        self.warnings.push(msg.into());
    }
}

/// Uninstall the Rusty-managed ML stack.
///
/// See the module docs for what is removed. Never panics; sudo steps degrade
/// gracefully when not root and sudo is unavailable.
pub fn uninstall_stack(opts: &UninstallOptions) -> anyhow::Result<UninstallReport> {
    let mut report = UninstallReport::default();
    let home = resolve_user_home();

    if !opts.yes {
        // Caller (CLI) is expected to confirm; this is the non-interactive guard.
        eprintln!(
            "[uninstall] Proceeding (use --yes to skip this notice). keep_rocm={}, purge_dir={}",
            opts.keep_rocm, opts.purge_mlstack_dir
        );
    }

    // 1. pip uninstall ML packages via the canonical Python.
    let python = resolve_canonical_python_bin();
    println!("[uninstall] Removing ML pip packages via {python} …");
    // Union the curated list with the installed-component registry's recorded
    // pip packages (Tenet 2: the registry is now populated at install time, so
    // uninstall consults it instead of relying solely on the hardcoded list).
    let mut pkgs: Vec<String> = ML_PIP_PACKAGES.iter().map(|s| s.to_string()).collect();
    pkgs.extend(crate::core::registry::InstalledComponentRegistry::load().all_pip_packages());
    pkgs.sort();
    pkgs.dedup();
    report.pip_uninstall_attempted = pkgs.clone();
    let mut pip_args = vec![
        "-m".to_string(),
        "pip".to_string(),
        "uninstall".to_string(),
        "-y".to_string(),
    ];
    pip_args.extend(pkgs);
    let pip_status = Command::new(&python).args(&pip_args).status();
    match pip_status {
        Ok(s) if s.success() => {}
        Ok(s) => report.note(format!(
            "pip uninstall exited non-zero ({s}) — some packages may not have been installed"
        )),
        Err(e) => report.note(format!("could not run {python} -m pip ({e})")),
    }

    // 2. ROCm/amdgpu system packages (cross-distro) unless --keep-rocm.
    if !opts.keep_rocm {
        // Pre-filter to only the installed packages: apt/pacman exit non-zero
        // if ANY named package in the purge list is absent (e.g. amdgpu-dkms on
        // a partial stack), which would abort the whole purge and leave valid
        // packages (e.g. rocm-core) installed. dnf/yum tolerate missing names,
        // but filtering is harmless there too. Only purge what's present.
        let installed = filter_installed_system_packages(ROCM_SYSTEM_PACKAGES);
        if installed.is_empty() {
            report.note(
                "no ROCm/amdgpu system packages are installed — skipping system-package purge",
            );
        } else if let Some((pm, purge_args)) = build_system_purge_cmd(&installed) {
            println!("[uninstall] Purging ROCm/amdgpu system packages via {pm} …");
            let ran = run_privileged(&pm, &purge_args, &mut report);
            report.system_packages_purged = ran;
        } else {
            report.note("no supported system package manager detected (apt/dnf/pacman/zypper) — skipping ROCm system-package purge");
        }

        // 3. /opt/rocm (sudo).
        if PathBuf::from("/opt/rocm").exists() {
            println!("[uninstall] Removing /opt/rocm …");
            report.opt_rocm_removed = run_privileged(
                "rm",
                &["-rf".to_string(), "/opt/rocm".to_string()],
                &mut report,
            );
        }
    } else {
        println!("[uninstall] --keep-rocm: leaving ROCm system packages and /opt/rocm in place");
    }

    // 4. Env files + shell sourcing lines.
    remove_env_files(&home, &mut report);
    strip_shell_sourcing(&home, &mut report);

    // 5. Registry.
    let mut registry = InstalledComponentRegistry::load();
    if !registry.is_empty() {
        registry.clear();
        if let Err(e) = registry.save() {
            report.note(format!("failed to clear registry: {e}"));
        } else {
            report.registry_cleared = true;
        }
    }

    // Optional: ~/.mlstack data root.
    if opts.purge_mlstack_dir {
        let root = crate::platform::environment::mlstack_root();
        if root.exists() {
            // The global venv / cache may contain root-owned bits; try plain,
            // then sudo if needed.
            if std::fs::remove_dir_all(&root).is_ok() {
                report
                    .env_files_removed
                    .push(format!("(dir) {}", root.display()));
            } else {
                let removed = run_privileged(
                    "rm",
                    &["-rf".to_string(), root.to_string_lossy().into_owned()],
                    &mut report,
                );
                if removed {
                    report
                        .env_files_removed
                        .push(format!("(dir, sudo) {}", root.display()));
                }
            }
        }
    }

    Ok(report)
}

/// Build a (program, args) purge command for the detected package manager, or
/// `None` if no supported manager is on PATH.
fn build_system_purge_cmd(packages: &[&str]) -> Option<(String, Vec<String>)> {
    let (pm, verb) = if command_on_path("apt") {
        (
            "apt",
            vec!["purge".to_string(), "-y".to_string(), "-qq".to_string()],
        )
    } else if command_on_path("pacman") {
        ("pacman", vec!["-Rn".to_string(), "--noconfirm".to_string()])
    } else if command_on_path("dnf") {
        ("dnf", vec!["remove".to_string(), "-y".to_string()])
    } else if command_on_path("zypper") {
        ("zypper", vec!["remove".to_string(), "-y".to_string()])
    } else if command_on_path("yum") {
        ("yum", vec!["remove".to_string(), "-y".to_string()])
    } else {
        return None;
    };
    let mut args = verb;
    args.extend(packages.iter().map(|s| s.to_string()));
    Some((pm.to_string(), args))
}

/// Filter `candidates` to only those that are actually installed, using the
/// detected package manager's "is installed" query. This makes the purge
/// tolerant of partial stacks: apt/pacman exit non-zero if any named package in
/// a purge list is absent, so we only pass installed names. Returns the
/// original list verbatim if no manager is detected (let the purge path emit its
/// own "no manager" note).
fn filter_installed_system_packages<'a>(candidates: &[&'a str]) -> Vec<&'a str> {
    // Return the installed candidates with the same lifetime as the input
    // (ROCM_SYSTEM_PACKAGES is &'static, so the call site gets &'static strs).
    candidates
        .iter()
        .copied()
        .filter(|pkg| is_system_package_installed(pkg))
        .collect()
}

/// Is `pkg` installed according to the detected package manager?
fn is_system_package_installed(pkg: &str) -> bool {
    // dpkg-query: exit 0 iff installed. (apt-backed distros.)
    if command_on_path("dpkg-query") {
        return Command::new("dpkg-query")
            .args(["-W", "-f=${Status}", pkg])
            .output()
            .map(|o| {
                o.status.success()
                    && String::from_utf8_lossy(&o.stdout).contains("install ok installed")
            })
            .unwrap_or(false);
    }
    // pacman -Q: exit 0 iff installed.
    if command_on_path("pacman") {
        return Command::new("pacman")
            .args(["-Q", pkg])
            .output()
            .map(|o| o.status.success())
            .unwrap_or(false);
    }
    // rpm -q: exit 0 iff installed (dnf/yum/zypper all back onto rpm).
    if command_on_path("rpm") {
        return Command::new("rpm")
            .args(["-q", pkg])
            .output()
            .map(|o| o.status.success())
            .unwrap_or(false);
    }
    // No detector: assume installed so the purge is attempted (the purge path
    // will note "no manager" if none exists).
    true
}

/// Run a command directly if root, otherwise via `sudo -n`. Returns `true` if
/// the command ran successfully. Never stalls on a hidden prompt: `sudo -n`
/// (non-interactive) fails fast instead of prompting for a password when no
/// TTY / cached credentials are available, so the command degrades to a warning
/// rather than hanging in CI/CD or SSH-without-TTY contexts.
fn run_privileged(program: &str, args: &[String], report: &mut UninstallReport) -> bool {
    let is_root = is_root();
    let (cmd_program, cmd_args) = if is_root {
        (program.to_string(), args.to_vec())
    } else if command_on_path("sudo") {
        // `-n` = non-interactive: fail instead of prompting. `-S` reads the
        // password from stdin only if one is pending; combined with `-n` this
        // never blocks. The caller passes no password, so sudo will refuse
        // rather than stall.
        let mut a = vec!["-n".to_string(), program.to_string()];
        a.extend_from_slice(args);
        ("sudo".to_string(), a)
    } else {
        report.note(format!(
            "skipping `{program} {args:?}` — not root and sudo unavailable",
        ));
        return false;
    };
    match Command::new(&cmd_program).args(&cmd_args).status() {
        Ok(s) if s.success() => true,
        Ok(s) => {
            report.note(format!("`{cmd_program}` exited non-zero ({s})"));
            false
        }
        Err(e) => {
            report.note(format!(
                "could not run `{cmd_program}` ({e}) — sudo may require a password (no TTY)"
            ));
            false
        }
    }
}

#[cfg(unix)]
fn is_root() -> bool {
    // SAFETY: geteuid is always safe on Unix.
    unsafe { libc::geteuid() == 0 }
}
#[cfg(not(unix))]
fn is_root() -> bool {
    false
}

/// Remove the env files Rusty wrote.
fn remove_env_files(home: &std::path::Path, report: &mut UninstallReport) {
    let targets = [
        home.join(".mlstack_env"),
        home.join(".config/fish/conf.d/mlstack_env.fish"),
        home.join(".rocm_env"),
    ];
    for t in targets {
        if t.exists() {
            match std::fs::remove_file(&t) {
                Ok(()) => report
                    .env_files_removed
                    .push(t.to_string_lossy().into_owned()),
                Err(e) => report.note(format!("could not remove {}: {e}", t.display())),
            }
        }
    }
}

/// Strip legacy `source ~/.mlstack_env` / `.mlstack_env` lines from shell rc
/// files (fish/bash/zsh). Idempotent: only rewrites if a line was actually
/// removed, and preserves the original trailing newline.
///
/// Only drops lines that actually SOURCE the env file — `source .mlstack_env`,
/// `. ~/.mlstack_env` (POSIX dot), or `bass source ...mlstack_env` (fish). A
/// bare mention of `.mlstack_env` in a comment/echo/assignment is NOT a source
/// line and is preserved. (The previous `t.contains(".")` condition was always
/// true for any `.mlstack_env` line and dropped everything mentioning it.)
fn strip_shell_sourcing(home: &std::path::Path, report: &mut UninstallReport) {
    let rcs = [
        home.join(".bashrc"),
        home.join(".zshrc"),
        home.join(".config/fish/config.fish"),
    ];
    let had_trailing_newline = |content: &str| content.ends_with('\n');
    for rc in rcs {
        let Ok(content) = std::fs::read_to_string(&rc) else {
            continue;
        };
        let mut filtered = String::with_capacity(content.len());
        let mut changed = false;
        for line in content.lines() {
            let t = line.trim();
            // A source line: it mentions .mlstack_env AND uses a source command
            // — `source`/`.` (POSIX dot-source at the start of the line)/`bass`
            // (fish wrapper). NOT a bare `.mlstack_env` mention (the old
            // `t.contains(".")` matched the dot in the filename itself).
            let is_source_line = t.contains(".mlstack_env")
                && (t.contains("source") || t.contains("bass") || t.starts_with(". "));
            if is_source_line {
                changed = true;
            } else {
                filtered.push_str(line);
                filtered.push('\n');
            }
        }
        if changed {
            // Preserve the original trailing-newline state. `content.lines()`
            // drops a trailing newline; we always re-add '\n' per line above, so
            // a file that originally ended without one would gain one — trim it
            // back to match. A file that ended with '\n' keeps it (the last
            // pushed '\n' stands in for the original terminator).
            if !had_trailing_newline(&content) && filtered.ends_with('\n') {
                filtered.pop();
            }
            let _ = std::fs::write(&rc, filtered);
            report
                .sourcing_lines_stripped
                .push(rc.to_string_lossy().into_owned());
        }
    }
}

/// Path to the managed global env (used by callers/tests).
pub fn global_env_dir() -> PathBuf {
    mlstack_global_dir()
}

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

    #[test]
    fn build_system_purge_cmd_apt_when_present() {
        // Only meaningful on a Debian host; just ensure it doesn't panic and
        // returns either Some(apt...) or None.
        let cmd = build_system_purge_cmd(&["rocm-hip-sdk"]);
        if command_on_path("apt") {
            let (pm, args) = cmd.expect("apt present");
            assert_eq!(pm, "apt");
            assert!(args.contains(&"purge".to_string()));
            assert!(args.contains(&"rocm-hip-sdk".to_string()));
        }
    }

    #[test]
    fn strip_sourcing_removes_mlstack_lines() {
        let dir = tempfile::tempdir().unwrap();
        let rc = dir.path().join(".bashrc");
        std::fs::write(
            &rc,
            "# my rc\nsource \"$HOME/.mlstack_env\"\nexport FOO=bar\n. ~/.mlstack_env\n",
        )
        .unwrap();
        let mut report = UninstallReport::default();
        strip_shell_sourcing(dir.path(), &mut report);
        let after = std::fs::read_to_string(&rc).unwrap();
        assert!(
            !after.contains(".mlstack_env"),
            "sourcing lines removed: {after}"
        );
        assert!(
            after.contains("export FOO=bar"),
            "other lines preserved: {after}"
        );
        assert_eq!(report.sourcing_lines_stripped.len(), 1);
        // Trailing newline preserved (original ended with '\n').
        assert!(
            after.ends_with('\n'),
            "trailing newline preserved: {after:?}"
        );
    }

    #[test]
    fn strip_sourcing_preserves_non_source_mentions() {
        // D1 regression: a comment / echo / assignment that merely MENTIONS
        // .mlstack_env is NOT a source line and must be kept. The old
        // `t.contains(".")` matched the dot in the filename and dropped these.
        let dir = tempfile::tempdir().unwrap();
        let rc = dir.path().join(".bashrc");
        let original = "# see ~/.mlstack_env for env\necho loaded .mlstack_env\nMLSTACK_ENV_FILE=.mlstack_env\n";
        std::fs::write(&rc, original).unwrap();
        let mut report = UninstallReport::default();
        strip_shell_sourcing(dir.path(), &mut report);
        let after = std::fs::read_to_string(&rc).unwrap();
        assert_eq!(
            report.sourcing_lines_stripped.len(),
            0,
            "no source lines, no rewrite: {after:?}"
        );
        // File untouched (changed == false → no write at all).
        assert!(
            after.contains("# see ~/.mlstack_env for env"),
            "comment preserved: {after}"
        );
        assert!(
            after.contains("MLSTACK_ENV_FILE=.mlstack_env"),
            "assignment preserved: {after}"
        );
    }

    #[test]
    fn remove_env_files_deletes_targets() {
        let dir = tempfile::tempdir().unwrap();
        std::fs::write(dir.path().join(".mlstack_env"), "x").unwrap();
        let mut report = UninstallReport::default();
        remove_env_files(dir.path(), &mut report);
        assert!(!dir.path().join(".mlstack_env").exists());
        assert!(!report.env_files_removed.is_empty());
    }
}