agentsec-core 0.2.0

//! Installer / uninstaller for AgentSec.
//!
//! Patches `~/.claude.json` (MCP entry) and `~/.claude/settings.json` (hooks).
//! All public functions accept [`Paths`] so tests can redirect paths via the
//! standard env-override mechanism.
//!
//! ## Dry-run default
//!
//! Both [`install`] and [`uninstall`] accept a `plan` with an `apply: bool`
//! field. When `apply` is `false` (the default) the functions compute what
//! *would* change and return a report, but no file is written and no backup
//! is created. Real writes only happen when `apply` is `true`.

use std::path::PathBuf;

use serde_json::Value;

use crate::config::Paths;
use crate::error::{Error, Result};

pub(crate) mod backup;
pub(crate) mod hooks;
pub(crate) mod mcp;

// ── public types ──────────────────────────────────────────────────────────────

/// Scope for the MCP entry and hook install.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum InstallScope {
    /// User-level scope: `~/.claude.json:mcpServers.agentsec`.
    User,
    /// Project-level scope: `~/.claude.json:projects.<cwd>.mcpServers.agentsec`.
    Project,
}

/// Parameters for an install operation.
#[derive(Debug, Clone)]
pub struct InstallPlan {
    /// Where to register the MCP entry.
    pub scope: InstallScope,
    /// Optional path to a `.env` file passed as `AGENTSEC_DOTENV` env var in
    /// the MCP entry.
    pub dotenv: Option<PathBuf>,
    /// Whether to register the hook entries in `~/.claude/settings.json`.
    pub with_hooks: bool,
    /// Overwrite existing entries even if they already exist.
    pub force: bool,
    /// If `false` (default), compute changes but do not write any files.
    /// Set `true` to apply mutations.
    pub apply: bool,
}

/// Parameters for an uninstall operation.
#[derive(Debug, Clone)]
pub struct UninstallPlan {
    /// Which scope's MCP entry to remove.
    pub scope: InstallScope,
    /// If `true`, leave the MCP entry in `~/.claude.json` intact.
    pub keep_mcp: bool,
    /// If `true`, leave the hook entries in `~/.claude/settings.json` intact.
    pub keep_hooks: bool,
    /// If `false` (default), compute changes but do not write any files.
    pub apply: bool,
}

/// Kind of change produced by an install/uninstall operation.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum ChangeKind {
    /// The entry was created fresh.
    Added,
    /// An existing entry was replaced (force mode).
    Updated,
    /// The entry was deleted.
    Removed,
    /// No change was needed (idempotent).
    NoOp,
}

/// A single file-level mutation.
#[derive(Debug, Clone)]
pub struct MutationChange {
    /// The file that was (or would be) modified.
    pub target: PathBuf,
    /// Kind of change.
    pub kind: ChangeKind,
    /// Human-readable description.
    pub description: String,
}

/// Report returned by [`install`] or [`uninstall`].
#[derive(Debug, Clone)]
pub struct InstallReport {
    /// Change to `~/.claude.json` (MCP entry), if any.
    pub mcp_change: Option<MutationChange>,
    /// Changes to `~/.claude/settings.json` (hooks), one per hook event.
    pub hooks_changes: Vec<MutationChange>,
    /// Paths of backup files created (`apply` mode only; dry-run leaves this
    /// empty).
    pub backups: Vec<PathBuf>,
    /// Whether the plan was applied (`apply = true`).
    pub applied: bool,
}

// ── public API ────────────────────────────────────────────────────────────────

/// Install AgentSec by patching `~/.claude.json` and optionally
/// `~/.claude/settings.json`.
///
/// When `plan.apply` is `false` (the default), no files are written; the
/// returned [`InstallReport`] describes what *would* happen.
pub fn install(paths: &Paths, plan: &InstallPlan) -> Result<InstallReport> {
    let mcp_path = paths.user_home.join(".claude.json");
    let hooks_path = paths.user_home.join(".claude/settings.json");

    // ── MCP entry ──
    let mut mcp_root = load_json_or_empty(&mcp_path)?;
    let mcp_kind = mcp::add_mcp_entry(
        &mut mcp_root,
        plan.scope,
        plan.dotenv.as_deref(),
        plan.force,
    );
    let mcp_change = Some(MutationChange {
        target: mcp_path.clone(),
        kind: mcp_kind.clone(),
        description: format!("MCP entry (scope={:?}): {:?}", plan.scope, mcp_kind),
    });

    // ── Hooks ──
    let mut hooks_root = if plan.with_hooks {
        load_json_or_empty(&hooks_path)?
    } else {
        Value::Null
    };
    let raw_hook_kinds = if plan.with_hooks {
        hooks::add_hooks(&mut hooks_root, plan.force)
    } else {
        vec![]
    };
    let hook_names = ["user-prompt-submit", "session-start"];
    let hooks_changes: Vec<MutationChange> = raw_hook_kinds
        .into_iter()
        .enumerate()
        .map(|(i, kind)| {
            let name = hook_names.get(i).copied().unwrap_or("unknown");
            MutationChange {
                target: hooks_path.clone(),
                kind: kind.clone(),
                description: format!("hook `agentsec hook {name}`: {kind:?}"),
            }
        })
        .collect();

    // ── Apply ──
    //
    // Per-target NoOp skip: if the only change for a file is `NoOp`,
    // skip both the backup and the write — there is literally nothing
    // to persist, and creating an `.bak.<epoch>` of an unchanged file
    // just litters the home dir on every dry-run-becomes-real run.
    let mcp_dirty = mcp_kind != ChangeKind::NoOp;
    let hooks_dirty = hooks_changes.iter().any(|c| c.kind != ChangeKind::NoOp);

    let mut backups = Vec::new();
    if plan.apply {
        // MCP
        if mcp_dirty {
            let bak = backup::backup(&mcp_path)?;
            if !bak.as_os_str().is_empty() {
                backups.push(bak);
            }
            write_json(&mcp_path, &mcp_root)?;
        }

        // Hooks
        if plan.with_hooks && hooks_dirty {
            // Ensure parent dir exists.
            if let Some(parent) = hooks_path.parent() {
                std::fs::create_dir_all(parent)?;
            }
            let bak = backup::backup(&hooks_path)?;
            if !bak.as_os_str().is_empty() {
                backups.push(bak);
            }
            write_json(&hooks_path, &hooks_root)?;
        }
    }

    Ok(InstallReport {
        mcp_change,
        hooks_changes,
        backups,
        applied: plan.apply,
    })
}

/// Uninstall AgentSec by removing entries from `~/.claude.json` and
/// `~/.claude/settings.json`.
///
/// When `plan.apply` is `false`, no files are written.
pub fn uninstall(paths: &Paths, plan: &UninstallPlan) -> Result<InstallReport> {
    let mcp_path = paths.user_home.join(".claude.json");
    let hooks_path = paths.user_home.join(".claude/settings.json");

    // ── MCP entry ──
    let mcp_change = if plan.keep_mcp {
        None
    } else {
        let mut mcp_root = load_json_or_empty(&mcp_path)?;
        let kind = mcp::remove_mcp_entry(&mut mcp_root, plan.scope);
        Some((
            mcp_root,
            MutationChange {
                target: mcp_path.clone(),
                kind: kind.clone(),
                description: format!("MCP entry (scope={:?}): {:?}", plan.scope, kind),
            },
        ))
    };

    // ── Hooks ──
    let hooks_result = if plan.keep_hooks {
        None
    } else {
        let mut hooks_root = load_json_or_empty(&hooks_path)?;
        let raw_kinds = hooks::remove_hooks(&mut hooks_root);
        Some((hooks_root, raw_kinds))
    };

    let hook_names = ["user-prompt-submit", "session-start"];
    let hooks_changes: Vec<MutationChange> = hooks_result
        .as_ref()
        .map(|(_, kinds)| {
            kinds
                .iter()
                .enumerate()
                .map(|(i, kind)| {
                    let name = hook_names.get(i).copied().unwrap_or("unknown");
                    MutationChange {
                        target: hooks_path.clone(),
                        kind: kind.clone(),
                        description: format!("hook `agentsec hook {name}`: {kind:?}"),
                    }
                })
                .collect()
        })
        .unwrap_or_default();

    let mcp_change_report = mcp_change.as_ref().map(|(_, c)| c.clone());

    // ── Apply ──
    //
    // Per-target NoOp skip (parallel to `install`): when the only
    // change for a target is `NoOp`, skip both backup and write —
    // otherwise re-running `uninstall --apply` on an already-clean
    // host produces a `.bak.<epoch>` of an unchanged file every time.
    let mcp_dirty = mcp_change
        .as_ref()
        .is_some_and(|(_, c)| c.kind != ChangeKind::NoOp);
    let hooks_dirty = hooks_changes.iter().any(|c| c.kind != ChangeKind::NoOp);

    let mut backups = Vec::new();
    if plan.apply {
        if mcp_dirty && let Some((mcp_root, _)) = &mcp_change {
            let bak = backup::backup(&mcp_path)?;
            if !bak.as_os_str().is_empty() {
                backups.push(bak);
            }
            write_json(&mcp_path, mcp_root)?;
        }
        if hooks_dirty && let Some((hooks_root, _)) = &hooks_result {
            let bak = backup::backup(&hooks_path)?;
            if !bak.as_os_str().is_empty() {
                backups.push(bak);
            }
            write_json(&hooks_path, hooks_root)?;
        }
    }

    Ok(InstallReport {
        mcp_change: mcp_change_report,
        hooks_changes,
        backups,
        applied: plan.apply,
    })
}

// ── private helpers ───────────────────────────────────────────────────────────

fn load_json_or_empty(path: &std::path::Path) -> Result<Value> {
    if !path.exists() {
        return Ok(Value::Object(serde_json::Map::new()));
    }
    let body = std::fs::read_to_string(path)?;
    if body.trim().is_empty() {
        return Ok(Value::Object(serde_json::Map::new()));
    }
    serde_json::from_str(&body)
        .map_err(|e| Error::Installer(format!("JSON parse error in {}: {e}", path.display())))
}

fn write_json(path: &std::path::Path, value: &Value) -> Result<()> {
    if let Some(parent) = path.parent() {
        std::fs::create_dir_all(parent)?;
    }
    let content = serde_json::to_string_pretty(value)?;
    std::fs::write(path, content)?;
    Ok(())
}

// ── unit tests ────────────────────────────────────────────────────────────────

#[cfg(test)]
mod tests {
    use super::*;
    use crate::LlmConfig;
    use crate::{Config, Paths};
    use tempfile::TempDir;

    fn test_paths(tmp: &TempDir) -> Paths {
        Paths {
            home: tmp.path().to_path_buf(),
            user_home: tmp.path().to_path_buf(),
        }
    }

    fn test_cfg(tmp: &TempDir) -> Config {
        Config {
            paths: test_paths(tmp),
            llm: LlmConfig {
                api_key: None,
                model: "claude-sonnet-4-5".to_string(),
            },
            paste: crate::config::PasteConfig::default(),
            web: crate::config::WebConfig::default(),
            dotenv_path: None,
        }
    }

    #[test]
    fn install_dry_run_no_file_mutation() {
        let tmp = TempDir::new().unwrap();
        let paths = test_paths(&tmp);
        let plan = InstallPlan {
            scope: InstallScope::User,
            dotenv: None,
            with_hooks: true,
            force: false,
            apply: false,
        };
        let report = install(&paths, &plan).unwrap();
        assert!(!report.applied);
        assert!(report.backups.is_empty());
        // No files written
        assert!(!tmp.path().join(".claude.json").exists());
        assert!(!tmp.path().join(".claude/settings.json").exists());
    }

    #[test]
    fn install_apply_creates_files() {
        let tmp = TempDir::new().unwrap();
        let paths = test_paths(&tmp);
        let plan = InstallPlan {
            scope: InstallScope::User,
            dotenv: None,
            with_hooks: true,
            force: false,
            apply: true,
        };
        let report = install(&paths, &plan).unwrap();
        assert!(report.applied);
        assert!(tmp.path().join(".claude.json").exists());
        assert!(tmp.path().join(".claude/settings.json").exists());
        // Verify MCP entry
        let mcp_content = std::fs::read_to_string(tmp.path().join(".claude.json")).unwrap();
        let mcp_json: Value = serde_json::from_str(&mcp_content).unwrap();
        assert!(mcp_json["mcpServers"]["agentsec"].is_object());
    }

    #[test]
    fn install_twice_is_idempotent() {
        let tmp = TempDir::new().unwrap();
        let paths = test_paths(&tmp);
        let plan = InstallPlan {
            scope: InstallScope::User,
            dotenv: None,
            with_hooks: true,
            force: false,
            apply: true,
        };
        install(&paths, &plan).unwrap();
        install(&paths, &plan).unwrap();

        let hooks_content =
            std::fs::read_to_string(tmp.path().join(".claude/settings.json")).unwrap();
        let hooks_json: Value = serde_json::from_str(&hooks_content).unwrap();
        // Should still have exactly 1 entry per event.
        let ups_len = hooks_json["hooks"]["UserPromptSubmit"]
            .as_array()
            .map_or(0, Vec::len);
        assert_eq!(ups_len, 1, "should not duplicate hook entries");
    }

    #[test]
    fn install_apply_creates_backup_when_file_existed() {
        let tmp = TempDir::new().unwrap();
        let paths = test_paths(&tmp);
        // Pre-create target files.
        std::fs::write(tmp.path().join(".claude.json"), "{}").unwrap();
        std::fs::create_dir_all(tmp.path().join(".claude")).unwrap();
        std::fs::write(tmp.path().join(".claude/settings.json"), "{}").unwrap();

        let plan = InstallPlan {
            scope: InstallScope::User,
            dotenv: None,
            with_hooks: true,
            force: false,
            apply: true,
        };
        let report = install(&paths, &plan).unwrap();
        assert_eq!(report.backups.len(), 2, "should create 2 backups");
        for bak in &report.backups {
            assert!(bak.exists());
        }
    }

    #[test]
    fn install_apply_skips_backup_when_all_changes_are_noop() {
        // Idempotency check: after a successful first apply, a second
        // apply against the same home dir should produce ChangeKind::NoOp
        // for every target and therefore skip backup creation entirely.
        // Without this skip, every re-run would litter the home with
        // an `.bak.<epoch>` of an unchanged file.
        let tmp = TempDir::new().unwrap();
        let paths = test_paths(&tmp);
        let plan = InstallPlan {
            scope: InstallScope::User,
            dotenv: None,
            with_hooks: true,
            force: false,
            apply: true,
        };
        // First apply: creates the files (backup count = 0 because
        // files didn't pre-exist; that's the existing semantics).
        let first = install(&paths, &plan).unwrap();
        assert!(first.applied);
        // Second apply: all NoOp, so no backup should be produced.
        let second = install(&paths, &plan).unwrap();
        assert!(second.applied);
        assert_eq!(
            second.mcp_change.as_ref().unwrap().kind,
            super::ChangeKind::NoOp
        );
        assert!(
            second
                .hooks_changes
                .iter()
                .all(|c| c.kind == super::ChangeKind::NoOp),
            "all hooks must report NoOp on second apply"
        );
        assert_eq!(
            second.backups.len(),
            0,
            "second apply must not create backups when nothing changes"
        );
    }

    #[test]
    fn uninstall_apply_skips_backup_when_nothing_to_remove() {
        // Re-running `uninstall --apply` on an already-clean host should
        // be a no-op: no backup, no write.
        let tmp = TempDir::new().unwrap();
        let paths = test_paths(&tmp);
        // Pre-create empty target files so load_json_or_empty succeeds
        // but contains nothing to remove.
        std::fs::write(tmp.path().join(".claude.json"), "{}").unwrap();
        std::fs::create_dir_all(tmp.path().join(".claude")).unwrap();
        std::fs::write(tmp.path().join(".claude/settings.json"), "{}").unwrap();

        let plan = UninstallPlan {
            scope: InstallScope::User,
            keep_mcp: false,
            keep_hooks: false,
            apply: true,
        };
        let report = uninstall(&paths, &plan).unwrap();
        assert!(report.applied);
        assert_eq!(
            report.mcp_change.as_ref().unwrap().kind,
            super::ChangeKind::NoOp
        );
        assert!(
            report
                .hooks_changes
                .iter()
                .all(|c| c.kind == super::ChangeKind::NoOp)
        );
        assert_eq!(
            report.backups.len(),
            0,
            "uninstall on clean host must not create backups"
        );
    }

    // Config helper (used by test_cfg above but needs to compile).
    #[allow(dead_code)]
    fn _use_cfg(tmp: &TempDir) {
        let _ = test_cfg(tmp);
    }
}