//! Deletes the `hyperhive-<unix-seconds>` access tokens `hive-c0re` used to
//! mint for agents on every spawn and rebuild, each one live on the forge
//! with write scopes.
//!
//! Two filters decide what goes, and both must pass:
//!
//! - **Whose tokens.** Only agents on the store's `hive-agent-*` roster, the
//!   one [`super::agent_token`]'s pass walks, and only those whose
//!   [`super::agent_token::AGENT_TOKEN_NAME`] token that pass would
//!   [`Decision::Keep`]: until the replacement is stored and live, the agent
//!   may still be reading its last `hyperhive-*` token from
//!   `<state>/forge-token`. [`CORE_USER`] is refused by name at every step.
//!   `hive-c0re` still names `core`'s live admin token
//!   `hyperhive-<unix-seconds>`, so nothing about the token tells them apart.
//! - **Which tokens.** A name that is exactly `hyperhive-` followed by one or
//!   more ASCII digits ([`is_legacy_token_name`]).
//!   [`super::agent_token::AGENT_TOKEN_NAME`] cannot match.
//!
//! Runs from [`super::agent_token::spawn`]'s periodic pass, off the same
//! roster observation, so a boot where that pass's first tick fails (the
//! store or forge unreachable) retries the sweep on the next tick instead of
//! leaving the tokens live until a restart. A failed read or delete is
//! logged and skipped; a re-run with nothing left to remove deletes nothing.

use anyhow::Result;

use super::Client;
use super::agent_token::{Decision, Observed};

/// The forge user `hive-c0re` runs as. Its admin token carries a legacy-shaped
/// name and is in use.
pub const CORE_USER: &str = "core";

/// The prefix `hive-c0re`'s `mint_token` put before the unix seconds.
const LEGACY_TOKEN_PREFIX: &str = "hyperhive-";

/// Whether `name` is exactly `hyperhive-<digits>`, the shape of every token
/// `hive-c0re` minted.
pub fn is_legacy_token_name(name: &str) -> bool {
    name.strip_prefix(LEGACY_TOKEN_PREFIX)
        .is_some_and(|secs| !secs.is_empty() && secs.bytes().all(|b| b.is_ascii_digit()))
}

/// The agents a sweep may touch: those whose
/// [`super::agent_token::AGENT_TOKEN_NAME`] token is current, never
/// [`CORE_USER`].
pub fn sweepable(observed: &[(String, Observed)]) -> Vec<String> {
    observed
        .iter()
        .filter(|(agent, o)| agent != CORE_USER && *o == Observed::Decided(Decision::Keep))
        .map(|(agent, _)| agent.clone())
        .collect()
}

impl Client {
    /// Delete every legacy token the forge lists for `user`, and return how
    /// many went. A delete the forge refuses is logged and skipped.
    async fn sweep_user(&self, user: &str) -> Result<usize> {
        if user == CORE_USER {
            return Ok(0);
        }
        let Some(listed) = self.list_agent_tokens(user).await? else {
            return Ok(0);
        };
        let mut removed = 0;
        for name in listed
            .iter()
            .filter_map(|t| t.name.as_deref())
            .filter(|n| is_legacy_token_name(n))
        {
            match self.api.admin_delete_user_access_token(user, name).await {
                Ok(()) => removed += 1,
                Err(e) if super::agent_token::is_not_found(&e) => {}
                Err(e) => tracing::warn!(
                    agent = user,
                    token = name,
                    error = %e,
                    "legacy forge token sweep: delete failed; skipped"
                ),
            }
        }
        Ok(removed)
    }

    /// Sweep each of `agents` and log what went, per agent and in total.
    /// Returns the total.
    pub(super) async fn sweep_legacy_tokens(&self, agents: &[String]) -> usize {
        let mut total = 0;
        for agent in agents {
            match self.sweep_user(agent).await {
                Ok(removed) => {
                    tracing::info!(agent, removed, "legacy forge token sweep: agent done");
                    total += removed;
                }
                Err(e) => tracing::warn!(
                    agent,
                    error = %format!("{e:#}"),
                    "legacy forge token sweep: listing failed; agent skipped"
                ),
            }
        }
        tracing::info!(
            agents = agents.len(),
            removed = total,
            "legacy forge token sweep: done"
        );
        total
    }
}

#[cfg(test)]
mod tests {
    use std::collections::BTreeMap;
    use std::sync::{Arc, Mutex};

    use forgejo_api::{Auth, Forgejo};

    use super::super::agent_token::{AGENT_TOKEN_NAME, MintReason};
    use super::*;

    #[test]
    fn only_hyperhive_digits_is_legacy() {
        for name in ["hyperhive-1", "hyperhive-1700000000"] {
            assert!(is_legacy_token_name(name), "{name}");
        }
        for name in [
            AGENT_TOKEN_NAME,
            "hyperhive",
            "hyperhive-",
            "hyperhive-abc",
            "hyperhive-123abc",
            "hyperhive-12 3",
            "hyperhive-+123",
            "xhyperhive-123",
            "hyperhive-123-x",
            "swarm-controller-boot-1700000000",
        ] {
            assert!(!is_legacy_token_name(name), "{name}");
        }
    }

    #[test]
    fn only_current_non_core_agents_are_sweepable() {
        let observed = [
            ("a".to_owned(), Observed::Decided(Decision::Keep)),
            (CORE_USER.to_owned(), Observed::Decided(Decision::Keep)),
            (
                "b".to_owned(),
                Observed::Decided(Decision::Mint(MintReason::NotOnForge)),
            ),
            ("c".to_owned(), Observed::Unknown),
            ("d".to_owned(), Observed::NoForgeUser),
            ("e".to_owned(), Observed::Decided(Decision::Conflict)),
            ("f".to_owned(), Observed::Decided(Decision::Keep)),
        ];
        assert_eq!(sweepable(&observed), ["a", "f"]);
    }

    /// Each user's token names, as the stub forge holds them.
    type Tokens = Arc<Mutex<BTreeMap<String, Vec<String>>>>;
    /// Every `DELETE` the stub forge was sent, as `(user, token)`.
    type Deletes = Arc<Mutex<Vec<(String, String)>>>;

    /// A stand-in forge on a loopback port answering the admin token list and
    /// delete from `tokens`. A delete of `fail` answers 500 and removes
    /// nothing.
    async fn stub_forge(tokens: Tokens, fail: (&'static str, &'static str)) -> (Client, Deletes) {
        use axum::http::{Method, StatusCode, Uri, header::CONTENT_TYPE};

        let deletes = Deletes::default();
        let recorded = deletes.clone();
        let app = axum::Router::new().fallback(move |method: Method, uri: Uri| {
            let tokens = tokens.clone();
            let recorded = recorded.clone();
            async move {
                let parts: Vec<&str> = uri.path().trim_matches('/').split('/').collect();
                let (status, body) = match (method, parts.as_slice()) {
                    (Method::GET, ["api", "v1", "admin", "users", user, "tokens"]) => {
                        match tokens.lock().unwrap().get(*user) {
                            Some(held) => {
                                let list: Vec<serde_json::Value> = held
                                    .iter()
                                    .enumerate()
                                    .map(|(i, name)| serde_json::json!({ "id": i, "name": name }))
                                    .collect();
                                (StatusCode::OK, serde_json::Value::from(list))
                            }
                            None => (
                                StatusCode::NOT_FOUND,
                                serde_json::json!({ "message": "user does not exist" }),
                            ),
                        }
                    }
                    (Method::DELETE, ["api", "v1", "admin", "users", user, "tokens", token]) => {
                        recorded
                            .lock()
                            .unwrap()
                            .push(((*user).to_owned(), (*token).to_owned()));
                        if (*user, *token) == fail {
                            (StatusCode::INTERNAL_SERVER_ERROR, serde_json::json!({}))
                        } else {
                            let mut all = tokens.lock().unwrap();
                            let held = all.entry((*user).to_owned()).or_default();
                            held.retain(|n| n != token);
                            (StatusCode::NO_CONTENT, serde_json::Value::Null)
                        }
                    }
                    _ => (
                        StatusCode::NOT_FOUND,
                        serde_json::json!({ "message": "not stubbed" }),
                    ),
                };
                let count = body.as_array().map_or(0, Vec::len).to_string();
                let body = if status == StatusCode::NO_CONTENT {
                    String::new()
                } else {
                    body.to_string()
                };
                (
                    status,
                    [
                        (CONTENT_TYPE.as_str(), "application/json".to_owned()),
                        ("x-total-count", count),
                    ],
                    body,
                )
            }
        });
        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
        let url = url::Url::parse(&format!("http://{}/", listener.local_addr().unwrap())).unwrap();
        tokio::spawn(async move { axum::serve(listener, app).await });
        let api = Forgejo::new(Auth::Token("stub-token"), url.clone()).unwrap();
        (Client { api, url }, deletes)
    }

    const MIX: [&str; 5] = [
        "hyperhive-123",
        "hyperhive-1700000000",
        "hyperhive-abc",
        "hyperhive",
        AGENT_TOKEN_NAME,
    ];

    fn forge_with_core_and_two_agents() -> Tokens {
        let held = |names: &[&str]| names.iter().map(|n| (*n).to_owned()).collect();
        Arc::new(Mutex::new(BTreeMap::from([
            (CORE_USER.to_owned(), held(&MIX)),
            ("alice".to_owned(), held(&MIX)),
            ("bob".to_owned(), held(&MIX)),
        ])))
    }

    fn sorted(deletes: &Deletes) -> Vec<(String, String)> {
        let mut d = deletes.lock().unwrap().clone();
        d.sort();
        d
    }

    fn pair(user: &str, token: &str) -> (String, String) {
        (user.to_owned(), token.to_owned())
    }

    /// Core is in the list handed to the sweep, as a stand-in for any path
    /// that lets it through [`sweepable`]; its tokens must survive anyway.
    #[tokio::test]
    async fn only_agents_legacy_tokens_go_and_a_rerun_removes_nothing() {
        let tokens = forge_with_core_and_two_agents();
        let (client, deletes) = stub_forge(tokens.clone(), ("", "")).await;
        let users = [CORE_USER.to_owned(), "alice".to_owned(), "bob".to_owned()];

        assert_eq!(client.sweep_legacy_tokens(&users).await, 4);
        assert_eq!(
            sorted(&deletes),
            [
                pair("alice", "hyperhive-123"),
                pair("alice", "hyperhive-1700000000"),
                pair("bob", "hyperhive-123"),
                pair("bob", "hyperhive-1700000000"),
            ]
        );
        let left = tokens.lock().unwrap().clone();
        assert_eq!(left[CORE_USER], MIX);
        for agent in ["alice", "bob"] {
            assert_eq!(
                left[agent],
                ["hyperhive-abc", "hyperhive", AGENT_TOKEN_NAME]
            );
        }

        deletes.lock().unwrap().clear();
        assert_eq!(client.sweep_legacy_tokens(&users).await, 0);
        assert!(deletes.lock().unwrap().is_empty());
    }

    #[tokio::test]
    async fn a_refused_delete_moves_on_to_the_next() {
        let tokens = forge_with_core_and_two_agents();
        let (client, deletes) = stub_forge(tokens.clone(), ("alice", "hyperhive-123")).await;
        let users = ["alice".to_owned(), "bob".to_owned()];

        assert_eq!(client.sweep_legacy_tokens(&users).await, 3);
        assert_eq!(deletes.lock().unwrap().len(), 4);
        assert_eq!(
            tokens.lock().unwrap()["alice"],
            [
                "hyperhive-123",
                "hyperhive-abc",
                "hyperhive",
                AGENT_TOKEN_NAME
            ]
        );
    }

    #[tokio::test]
    async fn a_user_the_forge_does_not_have_removes_nothing() {
        let tokens = forge_with_core_and_two_agents();
        let (client, deletes) = stub_forge(tokens, ("", "")).await;

        assert_eq!(client.sweep_legacy_tokens(&["ruth".to_owned()]).await, 0);
        assert!(deletes.lock().unwrap().is_empty());
    }
}