//! An agent's accounts on external forges: an operator hands us a base URL and
//! a token, we put them in the swarm's secret store.
//!
//! The agent end is `nix/agent-modules/forge-accounts.nix`, which lists the
//! agent's accounts and reads each under the agent's own certificate, and writes
//! the files `hive-forge -f <label>` reads. No hive is in the path.

use axum::Json;
use axum::extract::State;
use axum::http::StatusCode;
use serde::{Deserialize, Serialize};
use swarm_secret_client::forge;
use utoipa::ToSchema;

use super::{AppState, error_problem, swarm_hive};

/// The account to store for one agent's external forge.
///
/// No `Debug` derive: this carries a token.
#[derive(Deserialize, ToSchema)]
pub struct PutForgeAccountRequest {
    /// The forge's base URL, `http://` or `https://`. A trailing slash is
    /// dropped.
    #[schema(example = "https://codeberg.org")]
    url: String,
    /// The access token. Never logged, and never returned by this route.
    token: String,
}

/// `put_forge_account`'s success body.
#[derive(Debug, Serialize, ToSchema)]
pub struct PutForgeAccountResponse {
    /// The base URL as stored.
    url: String,
}

/// Store an agent's external forge account.
///
/// Idempotent: the store keeps versions, so repeating a call replaces the
/// account the agent will next read rather than adding a second one.
#[utoipa::path(
    put,
    path = "/api/hives/{hive}/agents/{agent}/forge-accounts/{label}",
    params(
        ("hive" = String, Path, description = "hive the agent runs on"),
        ("agent" = String, Path, description = "agent the account belongs to"),
        ("label" = String, Path, description = "the name the agent passes to `hive-forge -f`"),
    ),
    request_body = PutForgeAccountRequest,
    responses(
        (status = 200, description = "stored", body = PutForgeAccountResponse),
        (status = 400, description = "the agent or label is not an identifier, the URL is not http(s), the token is empty, or the hive is not in this swarm (problem+json)", body = String),
        (status = 500, description = "the store write failed (problem+json)", body = String),
    ),
    tag = "agents"
)]
pub async fn put_forge_account(
    State(state): State<AppState>,
    axum::extract::Path((hive, agent, label)): axum::extract::Path<(String, String, String)>,
    Json(req): Json<PutForgeAccountRequest>,
) -> Result<Json<PutForgeAccountResponse>, problem_details::ProblemDetails> {
    let hive = swarm_hive(&state, &hive).map_err(|(s, d)| error_problem(s, &d))?;
    let agent = hive_types::Ident::parse(&agent)
        .map_err(|reason| error_problem(StatusCode::BAD_REQUEST, reason))?
        .into_string();
    // `hive-forge` accepts only `[a-z0-9-]` after `-f`, narrower than the
    // store's charset, so a label it would refuse is refused here.
    let label = hive_types::Ident::parse(&label)
        .map_err(|reason| error_problem(StatusCode::BAD_REQUEST, reason))?
        .into_string();
    let secret_path = forge::account_path(&agent, &label)
        .map_err(|e| error_problem(StatusCode::BAD_REQUEST, &e.to_string()))?;
    let account = account(req).map_err(|e| error_problem(StatusCode::BAD_REQUEST, e))?;

    let store = crate::store::connect().await.map_err(|e| {
        tracing::warn!(error = %e, "connecting to the swarm secret store failed");
        error_problem(StatusCode::INTERNAL_SERVER_ERROR, &e.to_string())
    })?;
    store.write(&secret_path, &account).await.map_err(|e| {
        // The path names the agent and the label; the value is not in it.
        tracing::warn!(path = %secret_path, error = %e, "writing the forge account failed");
        error_problem(StatusCode::INTERNAL_SERVER_ERROR, &e.to_string())
    })?;

    tracing::info!(%hive, %agent, %label, url = %account.url, "forge account stored");
    Ok(Json(PutForgeAccountResponse { url: account.url }))
}

/// The request as it is stored, or why it cannot be.
fn account(req: PutForgeAccountRequest) -> Result<forge::Account, &'static str> {
    let url = req.url.trim().trim_end_matches('/');
    if !(url.starts_with("http://") || url.starts_with("https://")) {
        return Err("url must start with http:// or https://");
    }
    if req.token.trim().is_empty() {
        return Err("token is required");
    }
    Ok(forge::Account {
        value: req.token,
        url: url.to_owned(),
    })
}

#[cfg(test)]
mod tests {
    use super::{PutForgeAccountRequest, account};

    fn request(url: &str, token: &str) -> PutForgeAccountRequest {
        PutForgeAccountRequest {
            url: url.to_owned(),
            token: token.to_owned(),
        }
    }

    #[test]
    fn the_url_loses_its_trailing_slash_and_the_token_is_kept() {
        let a = account(request("https://codeberg.org/ ", "t0k3n")).expect("valid");
        assert_eq!(a.url, "https://codeberg.org");
        assert_eq!(a.value, "t0k3n");
    }

    #[test]
    fn a_url_that_is_not_http_is_refused() {
        assert!(account(request("codeberg.org", "t")).is_err());
        assert!(account(request("file:///etc/passwd", "t")).is_err());
        // The control: plain http is accepted.
        assert!(account(request("http://forge.lan", "t")).is_ok());
    }

    #[test]
    fn an_empty_token_is_refused() {
        assert!(account(request("https://codeberg.org", " ")).is_err());
    }

    /// Bare-minimum `AppState`, as `matrix_account`'s tests build it.
    fn state() -> super::super::AppState {
        super::super::AppState {
            hives: std::sync::Arc::new(vec![super::super::HiveEntry {
                name: "pr1ma".to_owned(),
                domain: "pr1ma.example".to_owned(),
            }]),
            links: std::sync::Arc::new(Vec::new()),
            status: None,
            wanted: None,
            agent_status: None,
            agent_icons: None,
            jobq: std::sync::Arc::new(std::sync::Mutex::new(hive_jobq::scheduler::Scheduler::new(
                hive_jobq::Graph::new(),
                hive_jobq::resources::ResourceTable::new(),
            ))),
            webhook_secret: None,
            config_prs: None,
            swarm_name: None,
            auth: None,
            forge: None,
            create_gate: std::sync::Arc::default(),
        }
    }

    async fn put(label: &str) -> problem_details::ProblemDetails {
        super::put_forge_account(
            axum::extract::State(state()),
            axum::extract::Path(("pr1ma".to_owned(), "atlas".to_owned(), label.to_owned())),
            axum::Json(request("https://codeberg.org", "t0k3n")),
        )
        .await
        .expect_err("no store is configured in a test")
    }

    /// A label `hive-forge -f` could not name is refused before the store: with
    /// `BAO_*` unset a store connect would answer 500.
    #[tokio::test]
    async fn a_label_hive_forge_cannot_name_is_refused_before_the_store() {
        for var in ["BAO_ADDR", "BAO_CLIENT_CERT", "BAO_CLIENT_KEY"] {
            assert!(
                std::env::var(var).is_err(),
                "{var} must be unset for this test to prove anything"
            );
        }
        for bad in ["Codeberg", "code_berg", "../x"] {
            let problem = put(bad).await;
            assert_eq!(
                problem.status,
                Some(axum::http::StatusCode::BAD_REQUEST),
                "{bad}: {problem:?}"
            );
        }
    }

    /// The control: a plain label reaches the store connect.
    #[tokio::test]
    async fn a_plain_label_reaches_the_store() {
        let problem = put("codeberg").await;
        assert_eq!(
            problem.status,
            Some(axum::http::StatusCode::INTERNAL_SERVER_ERROR),
            "{problem:?}"
        );
    }
}