//! Polling fallback for the config-PR webhook.
//!
//! The webhook (`/webhook/config-pr`) is the primary path for detecting open
//! PRs on `agent-configs/*` repos and queuing `MergeConfigPr` approvals.
//! But webhooks can be missed — hive-c0re might be down when a PR is opened,
//! or Forgejo might fail a delivery.
//!
//! This module provides [`poll_open_config_prs`], called periodically from
//! `main.rs`, which scans all `agent-configs/*` repos for open PRs that have
//! no pending `MergeConfigPr` approval yet, and queues one. Idempotent: PRs
//! that already have a pending approval are skipped.

use std::sync::Arc;

use anyhow::Result;
use forgejo_api::structs::{RepoListPullRequestsQuery, RepoListPullRequestsQueryState};

use crate::coordinator::Coordinator;
use crate::forge::CONFIG_ORG;

const HTTP_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(15);

/// Scan every repo in `agent-configs` for open PRs that have no pending
/// `MergeConfigPr` approval yet, and queue one for each gap found.
///
/// Designed to be called on a periodic timer (e.g. every 5 minutes) as a
/// fault-tolerance backstop for the Forgejo webhook. The webhook fires
/// immediately; this catches anything the webhook missed.
pub async fn poll_open_config_prs(core_token: &str, coord: &Arc<Coordinator>) -> Result<()> {
    let client = crate::forge::api(core_token)?;

    // List all repos in agent-configs org.
    let repos = tokio::time::timeout(HTTP_TIMEOUT, client.org_list_repos(CONFIG_ORG).all())
        .await
        .map_err(anyhow::Error::from)
        .and_then(|r| r.map_err(anyhow::Error::from))?;

    for repo in repos {
        let Some(repo_name) = repo.name.as_deref() else {
            continue;
        };
        // The repo name is the agent name (agent-configs/<agent>).
        let agent = repo_name;

        let query = RepoListPullRequestsQuery {
            state: Some(RepoListPullRequestsQueryState::Open),
            sort: None,
            milestone: None,
            labels: None,
            poster: None,
            base: None,
            head: None,
        };

        let prs = match tokio::time::timeout(
            HTTP_TIMEOUT,
            client
                .repo_list_pull_requests(CONFIG_ORG, repo_name, query)
                .all(),
        )
        .await
        {
            Ok(Ok(prs)) => prs,
            Ok(Err(e)) => {
                tracing::debug!(
                    %agent, error = %e,
                    "config-pr poll: listing PRs failed, skipping repo"
                );
                continue;
            }
            Err(_) => {
                tracing::debug!(
                    %agent,
                    "config-pr poll: timeout listing PRs, skipping repo"
                );
                continue;
            }
        };

        for pr in prs {
            let Some(pr_number) = pr.number.and_then(|n| u64::try_from(n).ok()) else {
                continue;
            };

            // Skip if a pending approval already exists for this PR.
            match coord
                .approvals
                .has_pending_merge_config_pr(agent, pr_number)
            {
                Ok(true) => {
                    tracing::debug!(
                        %agent, %pr_number,
                        "config-pr poll: approval already pending, skipping"
                    );
                    continue;
                }
                Ok(false) => {}
                Err(e) => {
                    tracing::warn!(
                        %agent, %pr_number, error = ?e,
                        "config-pr poll: DB check failed, skipping"
                    );
                    continue;
                }
            }

            tracing::info!(
                %agent, %pr_number,
                "config-pr poll: queuing missed MergeConfigPr approval"
            );
            let description = format!("PR #{pr_number} on {CONFIG_ORG}/{agent} (poll fallback)");
            if let Err(e) = crate::socket_server::submit_merge_config_pr(
                coord,
                agent,
                pr_number,
                Some(&description),
                "poll", // submitter — identifies the polling path in the audit trail
            )
            .await
            {
                tracing::warn!(
                    %agent, %pr_number, error = ?e,
                    "config-pr poll: failed to queue MergeConfigPr approval"
                );
            }
        }
    }

    Ok(())
}