#!/bin/bash
# ==============================================================================================
# ============================= Conf Cache Restore =============================================
# ==============================================================================================
#
# PURPOSE
# ─────────────────────────────────────────────────────────────────────────────
# Runs at array start after conf_sync.sh. Checks whether partner confs made it
# into the RAM cache. If any are missing (partner was unreachable at boot) and
# a persistent backup exists from the previous shutdown, loads the missing confs
# from backup into the RAM cache so scripts like fallback.sh have partner vars.
#
# Always removes the persistent backup when done — used or not.
#
# Normal reboot (partner up):
#   conf_sync.sh pulls fresh → RAM cache complete → backup not needed → removed
#
# Edge case (partner down at boot):
#   conf_sync.sh fails to pull → RAM cache missing partner → backup loaded into
#   RAM → backup removed → fallback.sh runs with last-known-good partner vars
#
# Own conf is never in the backup — it's always on disk.
#
# ==============================================================================================
# DESIGN PRINCIPLES
# ==============================================================================================
#
# Remove After Use
#   The persistent backup is always removed at the end of the run — whether it
#   was used or not. Stale backups from a previous shutdown should never be left
#   behind as a permanent fallback; the backup is a single-boot safety net, not
#   a long-lived cache.
#
# Partner Only
#   Own conf is on disk and is always available regardless of array or partner
#   state. Only partner confs can be missing after a boot — only those are
#   restored.
#
# ==============================================================================================
# OPERATIONAL SAFEGUARDS
# ==============================================================================================
#
#   require_partnership — exits early if PARTNERSHIP_ENABLED=false
#   detect_hosts()      — determines which conf files belong to partners vs self
#   No-backup guard     — exits cleanly if PERSISTENT_CONF_CACHE doesn't exist
#
# ==============================================================================================

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/../load_config.sh"

parse_args "$@"
detect_hosts
require_partnership

RAM_CACHE="$CONF_RAM_CACHE_DIR"
SAVE_DIR="$PERSISTENT_CONF_CACHE"

[[ "$DRY_RUN" == true ]] && warn "DRY RUN — no changes will be made"

if [[ ! -d "$SAVE_DIR" ]]; then
    log "No persistent conf backup found — nothing to restore"
    exit 0
fi

restored=0
for conf in "$SAVE_DIR"/host*.conf; do
    [[ -f "$conf" ]] || continue
    base="$(basename "$conf")"
    is_own_conf_file "$base" && continue

    if [[ -f "$RAM_CACHE/$base" ]]; then
        log "$base already in RAM cache (conf_sync succeeded) — skipping"
        continue
    fi

    if [[ "$DRY_RUN" == true ]]; then
        warn "DRY RUN — would restore $base → RAM cache"
        (( restored++ ))
        continue
    fi

    mkdir -p "$RAM_CACHE"
    if cp "$conf" "$RAM_CACHE/$base"; then
        echo "Restored $base from persistent backup → RAM cache ✅"
        (( restored++ ))
    else
        warn "Failed to restore $base"
    fi
done

[[ "$restored" -gt 0 ]] && \
    warn "Loaded $restored partner conf(s) from persistent backup — partner was unreachable at array start"

if [[ "$DRY_RUN" == false ]]; then
    rm -rf "$SAVE_DIR"
    log "Persistent conf backup cleared"
else
    warn "DRY RUN — would remove $SAVE_DIR"
fi

exit 0