//! Backlog promotion: scan `1_backlog/` and promote stories whose `depends_on` are all met.

use std::path::Path;

use crate::slog;
use crate::slog_warn;

use super::super::AgentPool;
use super::scan::scan_stage_items;
use super::story_checks::{check_archived_dependencies, has_unmet_dependencies};

impl AgentPool {
    /// Scan `1_backlog/` and promote any story whose `depends_on` are all met.
    ///
    /// A story is only promoted if it explicitly lists `depends_on` AND every
    /// listed dependency has reached `5_done` or `6_archived`.  Stories with no
    /// `depends_on` are left in the backlog for human scheduling.
    ///
    /// **Archived dep semantics:** a dep in `6_archived` counts as satisfied (since
    /// stories auto-sweep from `5_done` to `6_archived` after 4 hours, and the
    /// dependent story would normally already be promoted by then).  However, if a
    /// dep was already in `6_archived` when the dependent story was created (e.g. it
    /// was abandoned/superseded before the dependent existed), a prominent warning is
    /// logged so the user can see the promotion was triggered by an archived dep, not
    /// a clean completion.
    pub(super) fn promote_ready_backlog_stories(&self, project_root: &Path) {
        use crate::db::yaml_legacy::parse_front_matter;

        let items = scan_stage_items(project_root, "1_backlog");
        for story_id in &items {
            // Only promote stories that explicitly declare dependencies.
            let contents = crate::db::read_content(story_id);
            let has_deps = contents
                .and_then(|c| parse_front_matter(&c).ok())
                .and_then(|m| m.depends_on)
                .map(|d| !d.is_empty())
                .unwrap_or(false);
            if !has_deps {
                continue;
            }
            // Check whether any dependencies are still unmet.
            if has_unmet_dependencies(project_root, "1_backlog", story_id) {
                continue;
            }
            // Warn if any deps were satisfied via archive rather than via clean done.
            let archived_deps = check_archived_dependencies(project_root, "1_backlog", story_id);
            if !archived_deps.is_empty() {
                slog_warn!(
                    "[auto-assign] Story '{story_id}' is being promoted because deps \
                     {archived_deps:?} are in 6_archived (not cleanly completed via 5_done). \
                     These deps may have been abandoned or superseded. If this promotion is \
                     unintentional, remove the depends_on or manually move the story back to \
                     1_backlog."
                );
            }
            // All deps met — promote from backlog to current.
            slog!("[auto-assign] Story '{story_id}' deps met; promoting from backlog to current.");
            if let Err(e) = crate::agents::lifecycle::move_story_to_current(story_id) {
                slog!("[auto-assign] Failed to promote '{story_id}' to current: {e}");
            }
        }
    }
}