#!/usr/bin/env bash
set -euo pipefail

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
. "$ROOT_DIR/scripts/lib.sh"
load_env

# Determine rollback target
TARGET_TAG="${1:-}"
if [ -z "$TARGET_TAG" ]; then
  PREV_TAG_FILE="$ROOT_DIR/.deploy-state/previous-image-tag.txt"
  [ -f "$PREV_TAG_FILE" ] || fail_json "XUQM_PRIVATE_4030" \
    "no previous version recorded; pass target version as argument" "rollback"
  TARGET_TAG="$(cat "$PREV_TAG_FILE" | tr -d '[:space:]')"
fi

CURRENT_TAG="${IMAGE_TAG:-$(cat "$ROOT_DIR/VERSION" | tr -d '[:space:]')}"
audit "rollback" "STARTED" "from=$CURRENT_TAG to=$TARGET_TAG"
progress "rollback" "STARTED" "from=$CURRENT_TAG to=$TARGET_TAG"
printf 'Rolling back from %s to %s\n' "$CURRENT_TAG" "$TARGET_TAG"

# Confirm unless running in CI
if [ -t 0 ]; then
  printf 'Confirm rollback to %s (y/N): ' "$TARGET_TAG"
  read -r CONFIRM
  [ "$CONFIRM" = "y" ] || { printf 'Rollback cancelled.\n'; exit 0; }
fi

# Save current tag as future rollback point
printf '%s\n' "$CURRENT_TAG" > "$ROOT_DIR/.deploy-state/previous-image-tag.txt"

# Switch to target tag
set_env_value "$ROOT_DIR/.env" "IMAGE_TAG" "$TARGET_TAG"
set_env_value "$ROOT_DIR/.env" "PRIVATE_VERSION" "$TARGET_TAG"
load_env

# Pull target images
PROFILES="${COMPOSE_PROFILES:-base}"
COMPOSE_PROFILES="$PROFILES" compose pull
"$ROOT_DIR/scripts/render-config.sh"
COMPOSE_PROFILES="$PROFILES" compose up -d --remove-orphans

if ! "$ROOT_DIR/scripts/healthcheck.sh"; then
  fail_json "XUQM_PRIVATE_4031" "health check failed after rollback to $TARGET_TAG" "rollback"
fi

printf '%s\n' "$TARGET_TAG" > "$ROOT_DIR/VERSION"
audit "rollback" "DONE" "from=$CURRENT_TAG to=$TARGET_TAG"
progress "rollback" "DONE" "from=$CURRENT_TAG to=$TARGET_TAG"
printf 'Rollback complete: %s → %s\n' "$CURRENT_TAG" "$TARGET_TAG"