//! Bash arity dictionary for command-prefix allow rule matching.
//!
//! [`BashArityDict`] maps a command prefix (space-separated, lowercase) to the
//! number of positional (non-flag) words, *including the base command word*,
//! that form the canonical prefix.
//!
//! ## Invariant
//!
//! Flags (tokens starting with `-`) are **never** counted toward arity.
//! `auto_allow = ["git status"]` must match `git status -s` and
//! `git status --porcelain`, but **not** `git push`.
//!
//! ## Coverage
//!
//! 30+ common tools are covered across: git, npm, yarn, pnpm, cargo, docker,
//! kubectl, go, python/pip, gh, rustup, deno, bun, aws, terraform, make,
//! and more.

/// Static arity table: `(prefix, arity)`.
///
/// Arity is the total number of *positional* tokens (including the base
/// command) that form the canonical prefix.  For example:
///
/// * `("git status", 2)` — 2 positional tokens: `git` + `status`.
/// * `("npm run", 3)` — 3 positional tokens: `npm` + `run` + `<script>`.
/// * `("make", 1)` — only the base command, no sub-command.
pub static BASH_ARITY_TABLE: &[(&str, u8)] = &[
    // ── git ──────────────────────────────────────────────────────────────────
    ("git add", 2),
    ("git am", 2),
    ("git apply", 2),
    ("git bisect", 2),
    ("git blame", 2),
    ("git branch", 2),
    ("git cat-file", 2),
    ("git checkout", 2),
    ("git cherry-pick", 2),
    ("git clean", 2),
    ("git clone", 2),
    ("git commit", 2),
    ("git config", 2),
    ("git describe", 2),
    ("git diff", 2),
    ("git fetch", 2),
    ("git format-patch", 2),
    ("git grep", 2),
    ("git init", 2),
    ("git log", 2),
    ("git ls-files", 2),
    ("git merge", 2),
    ("git mv", 2),
    ("git notes", 2),
    ("git pull", 2),
    ("git push", 2),
    ("git rebase", 2),
    ("git reflog", 2),
    ("git remote", 2),
    ("git reset", 2),
    ("git restore", 2),
    ("git revert", 2),
    ("git rm", 2),
    ("git show", 2),
    ("git stash", 2),
    ("git status", 2),
    ("git submodule", 2),
    ("git switch", 2),
    ("git tag", 2),
    ("git worktree", 2),
    // ── npm ──────────────────────────────────────────────────────────────────
    ("npm audit", 2),
    ("npm build", 2),
    ("npm cache", 2),
    ("npm ci", 2),
    ("npm dedupe", 2),
    ("npm fund", 2),
    ("npm help", 2),
    ("npm info", 2),
    ("npm init", 2),
    ("npm install", 2),
    ("npm link", 2),
    ("npm list", 2),
    ("npm ls", 2),
    ("npm outdated", 2),
    ("npm pack", 2),
    ("npm prune", 2),
    ("npm publish", 2),
    ("npm rebuild", 2),
    ("npm run", 3),
    ("npm start", 2),
    ("npm stop", 2),
    ("npm test", 2),
    ("npm uninstall", 2),
    ("npm update", 2),
    ("npm version", 2),
    ("npm view", 2),
    // ── yarn ─────────────────────────────────────────────────────────────────
    ("yarn add", 2),
    ("yarn audit", 2),
    ("yarn build", 2),
    ("yarn install", 2),
    ("yarn run", 3),
    ("yarn start", 2),
    ("yarn test", 2),
    ("yarn upgrade", 2),
    ("yarn workspace", 3),
    // ── pnpm ─────────────────────────────────────────────────────────────────
    ("pnpm add", 2),
    ("pnpm build", 2),
    ("pnpm install", 2),
    ("pnpm run", 3),
    ("pnpm start", 2),
    ("pnpm test", 2),
    ("pnpm update", 2),
    // ── cargo ────────────────────────────────────────────────────────────────
    ("cargo add", 2),
    ("cargo bench", 2),
    ("cargo build", 2),
    ("cargo check", 2),
    ("cargo clean", 2),
    ("cargo clippy", 2),
    ("cargo doc", 2),
    ("cargo fix", 2),
    ("cargo fmt", 2),
    ("cargo generate", 2),
    ("cargo install", 2),
    ("cargo metadata", 2),
    ("cargo package", 2),
    ("cargo publish", 2),
    ("cargo remove", 2),
    ("cargo run", 2),
    ("cargo search", 2),
    ("cargo test", 2),
    ("cargo tree", 2),
    ("cargo uninstall", 2),
    ("cargo update", 2),
    ("cargo yank", 2),
    // ── docker ───────────────────────────────────────────────────────────────
    ("docker build", 2),
    ("docker compose", 3),
    ("docker container", 3),
    ("docker cp", 2),
    ("docker exec", 2),
    ("docker image", 3),
    ("docker images", 2),
    ("docker inspect", 2),
    ("docker kill", 2),
    ("docker logs", 2),
    ("docker network", 3),
    ("docker ps", 2),
    ("docker pull", 2),
    ("docker push", 2),
    ("docker rm", 2),
    ("docker rmi", 2),
    ("docker run", 2),
    ("docker start", 2),
    ("docker stop", 2),
    ("docker system", 3),
    ("docker tag", 2),
    ("docker volume", 3),
    // ── kubectl ──────────────────────────────────────────────────────────────
    ("kubectl apply", 2),
    ("kubectl create", 3),
    ("kubectl delete", 3),
    ("kubectl describe", 3),
    ("kubectl exec", 2),
    ("kubectl explain", 2),
    ("kubectl get", 3),
    ("kubectl label", 2),
    ("kubectl logs", 2),
    ("kubectl patch", 2),
    ("kubectl port-forward", 2),
    ("kubectl rollout", 3),
    ("kubectl scale", 2),
    ("kubectl set", 2),
    ("kubectl top", 3),
    // ── go ───────────────────────────────────────────────────────────────────
    ("go build", 2),
    ("go clean", 2),
    ("go env", 2),
    ("go fmt", 2),
    ("go generate", 2),
    ("go get", 2),
    ("go install", 2),
    ("go list", 2),
    ("go mod", 3),
    ("go run", 2),
    ("go test", 2),
    ("go vet", 2),
    ("go work", 3),
    // ── python / pip ─────────────────────────────────────────────────────────
    ("pip install", 2),
    ("pip uninstall", 2),
    ("pip list", 2),
    ("pip show", 2),
    ("pip freeze", 2),
    ("pip3 install", 2),
    ("pip3 uninstall", 2),
    ("pip3 list", 2),
    ("pip3 show", 2),
    ("python -m", 3),
    ("python3 -m", 3),
    // ── make / cmake ─────────────────────────────────────────────────────────
    ("make", 1),
    ("cmake", 1),
    // ── gh (GitHub CLI) ──────────────────────────────────────────────────────
    ("gh pr", 3),
    ("gh issue", 3),
    ("gh repo", 3),
    ("gh release", 3),
    ("gh workflow", 3),
    ("gh run", 3),
    ("gh secret", 3),
    // ── rustup ───────────────────────────────────────────────────────────────
    ("rustup default", 2),
    ("rustup install", 2),
    ("rustup show", 2),
    ("rustup target", 3),
    ("rustup toolchain", 3),
    ("rustup update", 2),
    // ── deno / bun ───────────────────────────────────────────────────────────
    ("deno run", 2),
    ("deno test", 2),
    ("deno fmt", 2),
    ("deno lint", 2),
    ("bun add", 2),
    ("bun build", 2),
    ("bun install", 2),
    ("bun run", 3),
    ("bun test", 2),
    ("npx", 2),
    // ── aws CLI ──────────────────────────────────────────────────────────────
    ("aws s3", 3),
    ("aws ec2", 3),
    ("aws iam", 3),
    ("aws lambda", 3),
    ("aws cloudformation", 3),
    ("aws ecs", 3),
    ("aws eks", 3),
    ("aws rds", 3),
    ("aws sts", 3),
    ("aws configure", 2),
    // ── terraform ────────────────────────────────────────────────────────────
    ("terraform init", 2),
    ("terraform plan", 2),
    ("terraform apply", 2),
    ("terraform destroy", 2),
    ("terraform validate", 2),
    ("terraform output", 2),
    ("terraform state", 3),
    ("terraform workspace", 3),
    // ── helm ─────────────────────────────────────────────────────────────────
    ("helm install", 2),
    ("helm upgrade", 2),
    ("helm uninstall", 2),
    ("helm list", 2),
    ("helm repo", 3),
    ("helm status", 2),
    ("helm template", 2),
];

/// Arity dictionary for bash command-prefix allow rules.
///
/// Provides arity-aware prefix extraction so that `auto_allow = ["git status"]`
/// correctly matches `git status -s` and `git status --porcelain` without
/// also matching `git push`.
///
/// # Example
///
/// ```rust
/// use deepseek_execpolicy::bash_arity::BashArityDict;
///
/// let dict = BashArityDict::new();
/// assert_eq!(dict.classify(&["git", "status", "-s"]),   "git status");
/// assert_eq!(dict.classify(&["git", "push", "origin"]), "git push");
/// assert_eq!(dict.classify(&["npm", "run", "dev"]),     "npm run dev");
/// assert_eq!(dict.classify(&["ls", "-la"]),             "ls");
/// ```
#[derive(Debug, Clone)]
pub struct BashArityDict {
    /// Internal table sorted longest-prefix-first for greedy matching.
    entries: Vec<(&'static str, u8)>,
}

impl BashArityDict {
    /// Construct a new dictionary pre-loaded with [`BASH_ARITY_TABLE`].
    #[must_use]
    pub fn new() -> Self {
        let mut entries: Vec<(&'static str, u8)> = BASH_ARITY_TABLE.to_vec();
        // Longest prefix first so greedy matching works correctly.
        entries.sort_by_key(|entry| std::cmp::Reverse(entry.0.len()));
        Self { entries }
    }

    /// Return the canonical command prefix for a slice of command tokens.
    ///
    /// # Algorithm
    ///
    /// 1. Strip all flag tokens (tokens that start with `-`).
    /// 2. Build candidates of depth 1..=3 from positional tokens (longest first).
    /// 3. If a candidate matches a dictionary entry, return `arity` positional
    ///    tokens joined with spaces.
    /// 4. If no dictionary entry matches, return the single base command name.
    #[must_use]
    pub fn classify(&self, tokens: &[&str]) -> String {
        if tokens.is_empty() {
            return String::new();
        }

        // Collect positional (non-flag) tokens, lowercased.
        let positional: Vec<String> = tokens
            .iter()
            .filter(|t| !t.starts_with('-'))
            .map(|t| t.to_ascii_lowercase())
            .collect();

        if positional.is_empty() {
            return String::new();
        }

        // Try candidates from longest to shortest (max depth 3).
        let max_depth = positional.len().min(3);
        for depth in (1..=max_depth).rev() {
            let candidate = positional[..depth].join(" ");
            if let Some(&(_key, arity)) = self
                .entries
                .iter()
                .find(|(key, _)| *key == candidate.as_str())
            {
                let take = (arity as usize).min(positional.len());
                return positional[..take].join(" ");
            }
        }

        // No match: return base command name only.
        positional[0].clone()
    }

    /// Return `true` if the allow-rule `pattern` (a command prefix string such
    /// as `"git status"`) matches the concrete command `command`.
    ///
    /// Matching is arity-aware:
    /// - `"git status"` matches `"git status -s"` and `"git status --porcelain"`.
    /// - `"git status"` does **not** match `"git push origin main"`.
    /// - Exact string patterns (e.g. `"ls"`) still work as before.
    ///
    /// For patterns that are not in the arity table, the function falls back to
    /// a plain prefix test on the normalised command so that existing exact-match
    /// rules continue to work unchanged.
    #[must_use]
    pub fn allow_rule_matches(&self, pattern: &str, command: &str) -> bool {
        let pattern_lower = pattern.trim().to_ascii_lowercase();
        let command_tokens: Vec<&str> = command.split_whitespace().collect();

        // Classify the concrete command through the arity dictionary.
        let canonical = self.classify(&command_tokens);

        // Primary check: the classified prefix equals the allow-rule pattern.
        if canonical == pattern_lower {
            return true;
        }

        // Fallback: plain normalised prefix match for patterns not in the table
        // (preserves backward compatibility with exact-match allow rules).
        let command_lower = command.trim().to_ascii_lowercase();
        // Normalise whitespace in both sides before comparing.
        let pattern_norm: String = pattern_lower
            .split_whitespace()
            .collect::<Vec<_>>()
            .join(" ");
        let command_norm: String = command_lower
            .split_whitespace()
            .collect::<Vec<_>>()
            .join(" ");
        command_norm == pattern_norm || command_norm.starts_with(&format!("{pattern_norm} "))
    }

    /// Iterate over all entries in the dictionary.
    pub fn entries(&self) -> impl Iterator<Item = (&str, u8)> {
        self.entries.iter().map(|(k, v)| (*k, *v))
    }

    /// Return the number of entries in the dictionary.
    #[must_use]
    pub fn len(&self) -> usize {
        self.entries.len()
    }

    /// Return `true` if the dictionary is empty.
    #[must_use]
    pub fn is_empty(&self) -> bool {
        self.entries.is_empty()
    }
}

impl Default for BashArityDict {
    fn default() -> Self {
        Self::new()
    }
}

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

    fn dict() -> BashArityDict {
        BashArityDict::new()
    }

    // ── classify ─────────────────────────────────────────────────────────────

    #[test]
    fn classify_git_status_bare() {
        assert_eq!(dict().classify(&["git", "status"]), "git status");
    }

    #[test]
    fn classify_git_status_with_short_flag() {
        assert_eq!(dict().classify(&["git", "status", "-s"]), "git status");
    }

    #[test]
    fn classify_git_status_with_long_flag() {
        assert_eq!(
            dict().classify(&["git", "status", "--porcelain"]),
            "git status"
        );
    }

    #[test]
    fn classify_git_push() {
        assert_eq!(
            dict().classify(&["git", "push", "origin", "main"]),
            "git push"
        );
    }

    #[test]
    fn classify_git_push_force() {
        assert_eq!(dict().classify(&["git", "push", "--force"]), "git push");
    }

    #[test]
    fn classify_npm_run_dev_arity_3() {
        assert_eq!(dict().classify(&["npm", "run", "dev"]), "npm run dev");
    }

    #[test]
    fn classify_npm_install() {
        assert_eq!(dict().classify(&["npm", "install"]), "npm install");
    }

    #[test]
    fn classify_cargo_check_with_flag() {
        assert_eq!(
            dict().classify(&["cargo", "check", "--workspace"]),
            "cargo check"
        );
    }

    #[test]
    fn classify_docker_compose_up_arity_3() {
        assert_eq!(
            dict().classify(&["docker", "compose", "up"]),
            "docker compose up"
        );
    }

    #[test]
    fn classify_kubectl_get_pods_arity_3() {
        assert_eq!(
            dict().classify(&["kubectl", "get", "pods"]),
            "kubectl get pods"
        );
    }

    #[test]
    fn classify_go_mod_tidy_arity_3() {
        assert_eq!(dict().classify(&["go", "mod", "tidy"]), "go mod tidy");
    }

    #[test]
    fn classify_make_no_subcommand() {
        assert_eq!(dict().classify(&["make", "all"]), "make");
    }

    #[test]
    fn classify_aws_s3_arity_3() {
        assert_eq!(dict().classify(&["aws", "s3", "ls"]), "aws s3 ls");
    }

    #[test]
    fn classify_terraform_plan() {
        assert_eq!(
            dict().classify(&["terraform", "plan", "-out=tfplan"]),
            "terraform plan"
        );
    }

    #[test]
    fn classify_unknown_falls_back_to_base() {
        assert_eq!(dict().classify(&["ls", "-la"]), "ls");
    }

    #[test]
    fn classify_empty_returns_empty() {
        assert_eq!(dict().classify(&[]), "");
    }

    // ── allow_rule_matches ────────────────────────────────────────────────────

    #[test]
    fn allow_rule_git_status_matches_with_flag() {
        assert!(dict().allow_rule_matches("git status", "git status -s"));
    }

    #[test]
    fn allow_rule_git_status_matches_porcelain() {
        assert!(dict().allow_rule_matches("git status", "git status --porcelain"));
    }

    #[test]
    fn allow_rule_git_status_does_not_match_push() {
        assert!(!dict().allow_rule_matches("git status", "git push origin main"));
    }

    #[test]
    fn allow_rule_git_status_does_not_match_checkout() {
        assert!(!dict().allow_rule_matches("git status", "git checkout main"));
    }

    #[test]
    fn allow_rule_npm_run_matches_dev() {
        assert!(dict().allow_rule_matches("npm run dev", "npm run dev"));
    }

    #[test]
    fn allow_rule_npm_run_dev_does_not_match_build() {
        assert!(!dict().allow_rule_matches("npm run dev", "npm run build"));
    }

    #[test]
    fn allow_rule_cargo_check_matches_with_flags() {
        assert!(dict().allow_rule_matches("cargo check", "cargo check --workspace"));
    }

    #[test]
    fn allow_rule_exact_match_still_works() {
        // A pattern not in the arity table falls back to exact/prefix match.
        assert!(dict().allow_rule_matches("ls", "ls -la"));
    }

    #[test]
    fn allow_rule_make_matches_with_target() {
        assert!(dict().allow_rule_matches("make", "make all"));
        assert!(dict().allow_rule_matches("make", "make clean"));
    }

    #[test]
    fn allow_rule_aws_s3_ls() {
        assert!(dict().allow_rule_matches("aws s3 ls", "aws s3 ls"));
        // "aws s3 cp" should not match "aws s3 ls"
        assert!(!dict().allow_rule_matches("aws s3 ls", "aws s3 cp src dst"));
    }

    // ── coverage count ────────────────────────────────────────────────────────

    #[test]
    fn dict_covers_at_least_30_commands() {
        // The issue requires 30+ common commands covered.
        assert!(
            BashArityDict::new().len() >= 30,
            "expected at least 30 entries, got {}",
            BashArityDict::new().len()
        );
    }
}
