#!/bin/bash
set -euo pipefail

ARTIFACT_DIR="/opt/api-artifacts"
CURRENT_LINK="$ARTIFACT_DIR/current"
SERVICE_NAME="api-server.service"

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

log_info() { echo -e "${GREEN}[INFO]${NC} $1"; }
log_warn() { echo -e "${YELLOW}[WARN]${NC} $1"; }
log_error() { echo -e "${RED}[ERROR]${NC} $1"; }

if [ ! -L "$CURRENT_LINK" ]; then
    log_error "No current deployment found"
    exit 1
fi

CURRENT_TARGET=$(readlink "$CURRENT_LINK")

if [ "$CURRENT_TARGET" = "blue" ]; then
    PREVIOUS_SLOT="green"
else
    PREVIOUS_SLOT="blue"
fi

PREVIOUS_LINK="$ARTIFACT_DIR/$PREVIOUS_SLOT"

if [ ! -L "$PREVIOUS_LINK" ]; then
    log_error "No previous deployment found to rollback to"
    exit 1
fi

PREVIOUS_BUILD=$(readlink "$PREVIOUS_LINK")

log_warn "ROLLBACK: Reverting from $CURRENT_TARGET to $PREVIOUS_SLOT"
log_info "Previous build: $PREVIOUS_BUILD"

read -p "Continue with rollback? (yes/no): " -r
if [[ ! $REPLY =~ ^[Yy][Ee][Ss]$ ]]; then
    log_warn "Rollback cancelled"
    exit 0
fi

log_info "Switching current symlink to $PREVIOUS_SLOT"
ln -sfn "$PREVIOUS_SLOT" "$CURRENT_LINK"

log_info "Reloading systemd service..."
systemctl reload-or-restart "$SERVICE_NAME"

sleep 5

if "$ARTIFACT_DIR/scripts/health-check.sh"; then
    log_info "Rollback successful!"
    log_info "Active deployment: $PREVIOUS_SLOT ($PREVIOUS_BUILD)"
else
    log_error "Health check failed after rollback - manual intervention required"
    exit 1
fi