//! Dashboard-driven external (non-internal) Forgejo/Gitea/Codeberg-compatible
//! forge accounts, per agent. Entirely dashboard-provisioned — there is no
//! host-side nix config for these (see `nix/host-modules/hive-forge/`'s
//! removed `extraForges` option). The operator manually creates a token on
//! the external forge themselves (however that forge lets them: PAT UI, a
//! teammate with admin, whatever) and pastes a label + base URL + token into
//! the dashboard's FORGES tab, same shape as the GitHub PAT flow
//! (`post_github_account`) plus the homeserver field from the matrix extra-
//! account flow (`post_matrix_account_login`).
//!
//! No remote account minting, no admin API, no revoke-on-the-remote-side —
//! this module only ever touches the *local* agent state dir. hive-c0re
//! persists the token to `<state>/forge-<label>-token` (0600) and the base
//! URL to a `<state>/forge-<label>.json` sidecar (not secret, but kept next
//! to the token so both survive together) via hive-priv. Listing derives the
//! configured set from those files, mirroring `matrix_accounts.rs`'s
//! filename-scan approach — there is no separate "catalog" now that there's
//! no nix config to enumerate.

use std::path::Path;

use axum::extract::{Form, Query};
use axum::response::{IntoResponse, Response};
use serde::{Deserialize, Serialize};

use super::{Ident, error_response};
use crate::coordinator::Coordinator;

#[derive(Deserialize)]
struct ForgeSidecar {
    base_url: String,
}

/// Read the base URL an agent stashed for `label` from its
/// `forge-<label>.json` sidecar. `None` if the sidecar is missing or
/// unparseable (e.g. a token file left over from a partial/older write).
fn read_base_url(dir: &Path, label: &str) -> Option<String> {
    let s = std::fs::read_to_string(dir.join(format!("forge-{label}.json"))).ok()?;
    serde_json::from_str::<ForgeSidecar>(&s)
        .ok()
        .map(|s| s.base_url)
}

#[derive(Serialize)]
struct ExtraForgeAccount {
    label: String,
    base_url: Option<String>,
}

#[derive(Serialize)]
struct ExtraForgesResponse {
    forges: Vec<ExtraForgeAccount>,
}

#[derive(Deserialize)]
pub(super) struct ExtraForgesQuery {
    agent: String,
}

/// `GET /api/extra-forges?agent=<name>` — list the external forge accounts
/// currently provisioned for `agent`, derived from every `forge-<label>-
/// token` file in its state dir (mirrors `matrix_accounts.rs`'s filename-scan
/// listing). `base_url` is backfilled from the matching `forge-<label>.json`
/// sidecar when present. Never returns a token.
pub(super) async fn get_extra_forges(Query(q): Query<ExtraForgesQuery>) -> Response {
    let agent = q.agent.trim();
    let Ok(agent) = Ident::parse(agent) else {
        return error_response(&format!("extra-forges: invalid agent {agent:?}"));
    };
    let dir = Coordinator::agent_notes_dir(&agent);
    let mut forges = Vec::new();
    match std::fs::read_dir(&dir) {
        Ok(entries) => {
            for entry in entries.flatten() {
                if !entry.file_type().is_ok_and(|ft| ft.is_file()) {
                    continue;
                }
                let fname = entry.file_name();
                let Some(fname) = fname.to_str() else {
                    continue;
                };
                // `forge-token` (no suffix) is the mandatory internal forge —
                // not one of these dashboard-provisioned extra accounts.
                let Some(label) = fname
                    .strip_prefix("forge-")
                    .and_then(|s| s.strip_suffix("-token"))
                else {
                    continue;
                };
                if label.is_empty() {
                    continue;
                }
                forges.push(ExtraForgeAccount {
                    base_url: read_base_url(&dir, label),
                    label: label.to_owned(),
                });
            }
        }
        Err(e) if e.kind() == std::io::ErrorKind::NotFound => {}
        Err(e) => {
            return error_response(&format!("extra-forges: read {}: {e}", dir.display()));
        }
    }
    forges.sort_by(|a, b| a.label.cmp(&b.label));
    axum::Json(ExtraForgesResponse { forges }).into_response()
}

/// Form body for `POST /api/extra-forge-account` (urlencoded, the
/// dashboard's mutation convention). `action` is `"add"` (needs `base_url` +
/// `token`) or `"remove"`.
#[derive(Deserialize)]
pub(super) struct ExtraForgeAccountForm {
    agent: String,
    label: String,
    action: String,
    base_url: Option<String>,
    token: Option<String>,
}

#[derive(Serialize)]
struct ExtraForgeAccountResult {
    ok: bool,
}

/// `POST /api/extra-forge-account` — add persists the operator-pasted
/// label/base-URL/token to the agent's state dir via hive-priv; remove
/// deletes both files. Purely local — no remote account creation or
/// revocation, there is no admin access assumed on the external forge.
/// Operator-authenticated (dashboard). Never echoes the token back.
pub(super) async fn post_extra_forge_account(Form(f): Form<ExtraForgeAccountForm>) -> Response {
    let agent = f.agent.trim();
    let label = f.label.trim();
    let Ok(agent) = Ident::parse(agent) else {
        return error_response(&format!("extra-forge-account: invalid agent {agent:?}"));
    };
    let Ok(label) = Ident::parse(label) else {
        return error_response(&format!("extra-forge-account: invalid label {label:?}"));
    };

    match f.action.as_str() {
        "add" => {
            let base_url = f.base_url.as_deref().unwrap_or_default().trim();
            let base_url = base_url.trim_end_matches('/');
            if !(base_url.starts_with("http://") || base_url.starts_with("https://")) {
                return error_response(&format!(
                    "extra-forge-account: base_url must be an http(s) URL, got {base_url:?}"
                ));
            }
            let Some(token) = f.token.as_deref().filter(|t| !t.is_empty()) else {
                return error_response("extra-forge-account: token is required");
            };
            if let Err(e) = crate::priv_client::write_agent_extra_forge_account(
                agent.as_str(),
                label.as_str(),
                base_url,
                token,
            )
            .await
            {
                return error_response(&format!(
                    "extra-forge-account: write account failed: {e:#}"
                ));
            }
            tracing::info!(%agent, %label, "extra-forge-account: provisioned");
        }
        "remove" => {
            if let Err(e) =
                crate::priv_client::delete_agent_extra_forge_account(agent.as_str(), label.as_str())
                    .await
            {
                return error_response(&format!(
                    "extra-forge-account: delete account failed: {e:#}"
                ));
            }
            tracing::info!(%agent, %label, "extra-forge-account: removed");
        }
        other => {
            return error_response(&format!(
                "extra-forge-account: unknown action {other:?} (want add|remove)"
            ));
        }
    }
    axum::Json(ExtraForgeAccountResult { ok: true }).into_response()
}