use std::path::{Path, PathBuf};
use serde::Deserialize;
use serde_json::{Map, Value, json};
use super::{HookFormat, HookInput, HookResponse, InstallOutcome, ParseError, Target, allow_reason};
use crate::verdict::Verdict;
pub struct ClaudeTarget;
impl Target for ClaudeTarget {
fn name(&self) -> &'static str {
"claude"
}
fn display_name(&self) -> &'static str {
"Claude Code"
}
fn detect_paths(&self, home: &Path) -> Vec<PathBuf> {
vec![home.join(".claude")]
}
fn install(&self, home: &Path) -> Result<InstallOutcome, String> {
let dir = home.join(".claude");
if !dir.exists() {
return Ok(InstallOutcome::Skipped {
reason: format!(
"~/.claude not found at {} (Claude Code not installed)",
dir.display()
),
});
}
let path = dir.join("settings.json");
let binary = "safe-chains";
if path.exists() {
let contents = std::fs::read_to_string(&path)
.map_err(|e| format!("Could not read {}: {e}", path.display()))?;
let mut settings: Value = serde_json::from_str(&contents)
.map_err(|e| format!("Could not parse {}: {e}", path.display()))?;
if has_safe_chains_hook(&settings) {
return Ok(InstallOutcome::AlreadyConfigured { path });
}
add_hook(&mut settings, binary);
let output = serde_json::to_string_pretty(&settings).expect("serializing valid JSON");
std::fs::write(&path, format!("{output}\n"))
.map_err(|e| format!("Could not write {}: {e}", path.display()))?;
Ok(InstallOutcome::Installed { path })
} else {
let mut settings = Value::Object(Map::new());
add_hook(&mut settings, binary);
let output = serde_json::to_string_pretty(&settings).expect("serializing valid JSON");
std::fs::write(&path, format!("{output}\n"))
.map_err(|e| format!("Could not write {}: {e}", path.display()))?;
Ok(InstallOutcome::Installed { path })
}
}
fn hook_format(&self) -> Option<&dyn HookFormat> {
Some(&ClaudeHookFormat)
}
}
struct ClaudeHookFormat;
#[derive(Deserialize)]
struct ToolInput {
command: String,
}
#[derive(Deserialize)]
struct ClaudeHookEnvelope {
tool_input: ToolInput,
#[serde(default)]
cwd: Option<String>,
}
impl HookFormat for ClaudeHookFormat {
fn parse_input(&self, stdin: &str) -> Result<HookInput, ParseError> {
let envelope: ClaudeHookEnvelope = serde_json::from_str(stdin).map_err(|e| ParseError {
message: e.to_string(),
})?;
Ok(HookInput {
command: envelope.tool_input.command,
cwd: envelope.cwd,
})
}
fn render_response(&self, verdict: Verdict) -> HookResponse {
if verdict.is_allowed() {
let reason = allow_reason(verdict);
let body = json!({
"hookSpecificOutput": {
"hookEventName": "PreToolUse",
"permissionDecision": "allow",
"permissionDecisionReason": reason,
}
});
HookResponse {
stdout: serde_json::to_string(&body).unwrap_or_default(),
exit_code: 0,
}
} else {
HookResponse {
stdout: String::new(),
exit_code: 0,
}
}
}
}
fn hook_entry(binary: &str) -> Value {
json!({
"matcher": "Bash",
"hooks": [{
"type": "command",
"command": binary,
}]
})
}
fn has_safe_chains_hook(settings: &Value) -> bool {
settings
.get("hooks")
.and_then(|h| h.get("PreToolUse"))
.and_then(|arr| arr.as_array())
.is_some_and(|entries| {
entries.iter().any(|entry| {
entry
.get("hooks")
.and_then(|h| h.as_array())
.is_some_and(|hooks| {
hooks.iter().any(|hook| {
hook.get("command")
.and_then(|c| c.as_str())
.is_some_and(|cmd| cmd.contains("safe-chains"))
})
})
})
})
}
fn add_hook(settings: &mut Value, binary: &str) {
if !settings.is_object() {
*settings = json!({});
}
let Some(obj) = settings.as_object_mut() else {
unreachable!("settings was just set to an object");
};
let hooks = obj
.entry("hooks")
.or_insert_with(|| json!({}))
.as_object_mut()
.expect("hooks key was created above as an object");
let pre_tool_use = hooks
.entry("PreToolUse")
.or_insert_with(|| json!([]))
.as_array_mut()
.expect("PreToolUse key was created above as an array");
pre_tool_use.push(hook_entry(binary));
}
#[cfg(test)]
mod tests {
use super::*;
use crate::verdict::SafetyLevel;
fn target() -> ClaudeTarget {
ClaudeTarget
}
#[test]
fn install_no_claude_dir_skips() {
let dir = tempfile::tempdir().unwrap();
let outcome = target().install(dir.path()).unwrap();
assert!(matches!(outcome, InstallOutcome::Skipped { .. }));
}
#[test]
fn install_creates_settings_file() {
let dir = tempfile::tempdir().unwrap();
std::fs::create_dir(dir.path().join(".claude")).unwrap();
let outcome = target().install(dir.path()).unwrap();
assert!(matches!(outcome, InstallOutcome::Installed { .. }));
let contents =
std::fs::read_to_string(dir.path().join(".claude/settings.json")).unwrap();
let settings: Value = serde_json::from_str(&contents).unwrap();
assert!(has_safe_chains_hook(&settings));
}
#[test]
fn install_preserves_existing_settings() {
let dir = tempfile::tempdir().unwrap();
let claude_dir = dir.path().join(".claude");
std::fs::create_dir(&claude_dir).unwrap();
std::fs::write(
claude_dir.join("settings.json"),
r#"{"permissions": {"allow": ["Bash(cargo test *)"]}}"#,
)
.unwrap();
target().install(dir.path()).unwrap();
let contents = std::fs::read_to_string(claude_dir.join("settings.json")).unwrap();
let settings: Value = serde_json::from_str(&contents).unwrap();
assert!(has_safe_chains_hook(&settings));
assert!(
settings
.get("permissions")
.and_then(|p| p.get("allow"))
.is_some(),
"existing permissions must be preserved"
);
}
#[test]
fn install_idempotent() {
let dir = tempfile::tempdir().unwrap();
std::fs::create_dir(dir.path().join(".claude")).unwrap();
target().install(dir.path()).unwrap();
let outcome = target().install(dir.path()).unwrap();
assert!(matches!(outcome, InstallOutcome::AlreadyConfigured { .. }));
}
#[test]
fn detect_paths_returns_claude_dir() {
let dir = tempfile::tempdir().unwrap();
let paths = target().detect_paths(dir.path());
assert_eq!(paths, vec![dir.path().join(".claude")]);
}
#[test]
fn parse_input_extracts_command() {
let stdin = r#"{"tool_input": {"command": "ls -la"}, "cwd": "/tmp"}"#;
let parsed = ClaudeHookFormat.parse_input(stdin).unwrap();
assert_eq!(parsed.command, "ls -la");
assert_eq!(parsed.cwd.as_deref(), Some("/tmp"));
}
#[test]
fn parse_input_rejects_garbage() {
assert!(ClaudeHookFormat.parse_input("not json").is_err());
assert!(ClaudeHookFormat.parse_input("{}").is_err());
}
#[test]
fn render_response_allow_emits_allow_envelope() {
let r = ClaudeHookFormat.render_response(Verdict::Allowed(SafetyLevel::Inert));
assert_eq!(r.exit_code, 0);
let v: Value = serde_json::from_str(&r.stdout).unwrap();
assert_eq!(
v.pointer("/hookSpecificOutput/permissionDecision")
.and_then(|d| d.as_str()),
Some("allow"),
);
}
#[test]
fn render_response_deny_emits_empty_body() {
let r = ClaudeHookFormat.render_response(Verdict::Denied);
assert_eq!(r.exit_code, 0);
assert_eq!(r.stdout, "");
}
#[test]
fn render_response_safewrite_carries_appropriate_reason() {
let r = ClaudeHookFormat.render_response(Verdict::Allowed(SafetyLevel::SafeWrite));
let v: Value = serde_json::from_str(&r.stdout).unwrap();
assert_eq!(
v.pointer("/hookSpecificOutput/permissionDecisionReason")
.and_then(|s| s.as_str()),
Some(allow_reason(Verdict::Allowed(SafetyLevel::SafeWrite))),
);
}
}