#!/bin/bash
# Usage: curl -sL https://url/migrate.sh | bash -s -- <LOCAL_ID> <USER@REMOTE_IP> <REMOTE_ID> [SSH_KEY_PATH]

LOCAL_SEARCH="$1"
DEST_CONN="$2"
REMOTE_SEARCH="$3"
SSH_KEY_PATH="$4"

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

# --- 1. CONFIGURE SSH ---
# Base options to avoid "Are you sure?" prompts and timeouts
SSH_BASE_OPTS="-o BatchMode=yes -o ConnectTimeout=10 -o StrictHostKeyChecking=no"

if [ -n "$SSH_KEY_PATH" ]; then
    echo -e "🔑 Using Identity File: ${YELLOW}$SSH_KEY_PATH${NC}"
    if [ ! -f "$SSH_KEY_PATH" ]; then
        echo -e "${RED}Error: Key file not found at $SSH_KEY_PATH${NC}"
        exit 1
    fi
    # Create the SSH command with the key
    SSH_CMD="ssh -i $SSH_KEY_PATH $SSH_BASE_OPTS"
    # Create the RSYNC generic shell command
    RSYNC_SH="ssh -i $SSH_KEY_PATH $SSH_BASE_OPTS"
else
    SSH_CMD="ssh $SSH_BASE_OPTS"
    RSYNC_SH="ssh $SSH_BASE_OPTS"
fi

# --- 2. PRE-FLIGHT CHECKS ---
if [ -z "$REMOTE_SEARCH" ]; then
  echo -e "${RED}Usage: $0 <Local_ID> <User@Remote_IP> <Remote_ID> [Key_Path]${NC}"
  exit 1
fi

echo -e "📡 Connecting to $DEST_CONN..."
if ! $SSH_CMD "$DEST_CONN" echo "SSH Connection OK" >/dev/null 2>&1; then
    echo -e "${RED}Error: Cannot connect to $DEST_CONN.${NC}"
    echo -e "   Check your IP, User, or SSH Key permissions."
    exit 1
fi

# --- 3. IDENTIFY CONTAINERS ---
echo -e "\n🔍 Identifying Containers..."

# Local
L_ID=$(docker ps -aq --filter "name=${LOCAL_SEARCH}" | head -n 1)
L_NAME=$(docker ps -a --filter "name=${LOCAL_SEARCH}" --format "{{.Names}}" | head -n 1)

# Remote (via SSH)
R_ID=$($SSH_CMD "$DEST_CONN" "docker ps -aq --filter 'name=${REMOTE_SEARCH}' | head -n 1")
R_NAME=$($SSH_CMD "$DEST_CONN" "docker ps -a --filter 'name=${REMOTE_SEARCH}' --format '{{.Names}}' | head -n 1")

if [ -z "$L_ID" ]; then echo -e "${RED}Local container '${LOCAL_SEARCH}' not found.${NC}"; exit 1; fi
if [ -z "$R_ID" ]; then echo -e "${RED}Remote container '${REMOTE_SEARCH}' not found on Server B.${NC}"; exit 1; fi

echo -e "   Source: ${GREEN}$L_NAME${NC} ($L_ID)"
echo -e "   Target: ${GREEN}$R_NAME${NC} ($R_ID)"

# --- 4. STOP CONTAINERS ---
echo -e "\n🛑 ${RED}Stopping containers to freeze state...${NC}"
docker stop "$L_ID"
$SSH_CMD "$DEST_CONN" "docker stop $R_ID"

# --- 5. MIGRATE VOLUMES ---
echo -e "\n📦 Mapping & Syncing Volumes..."

# Get Mounts: Type|SourcePath|InternalPath
L_MOUNTS=$(docker inspect -f '{{range .Mounts}}{{.Type}}|{{.Source}}|{{.Destination}} {{end}}' "$L_ID")

for MOUNT in $L_MOUNTS; do
    TYPE=$(echo "$MOUNT" | cut -d'|' -f1)
    L_PATH=$(echo "$MOUNT" | cut -d'|' -f2)
    INTERNAL_TARGET=$(echo "$MOUNT" | cut -d'|' -f3)

    # Skip system mounts
    if [[ "$INTERNAL_TARGET" == *".sock" ]] || [[ "$INTERNAL_TARGET" == *".conf" ]]; then continue; fi

    echo -e "\n   🔄 Volume: ${YELLOW}$INTERNAL_TARGET${NC}"

    # Find corresponding path on Remote
    R_PATH_RAW=$($SSH_CMD "$DEST_CONN" "docker inspect -f '{{range .Mounts}}{{if eq .Destination \"$INTERNAL_TARGET\"}}{{.Source}}{{end}}{{end}}' $R_ID")

    if [ -z "$R_PATH_RAW" ]; then
        echo -e "      ${RED}Skipping: Target has no matching volume.${NC}"
        continue
    fi

    # Resolve Real Paths
    if [ "$TYPE" == "volume" ]; then
        REAL_L_PATH=$(docker volume inspect --format '{{.Mountpoint}}' "$L_PATH")
        REAL_R_PATH=$($SSH_CMD "$DEST_CONN" "docker volume inspect --format '{{.Mountpoint}}' $R_PATH_RAW 2>/dev/null || echo $R_PATH_RAW")
    else
        REAL_L_PATH="$L_PATH"
        REAL_R_PATH="$R_PATH_RAW"
    fi

    # RSYNC EXECUTION
    echo "      🚀 Transferring data..."
    rsync -az --info=progress2 -e "$RSYNC_SH" "${REAL_L_PATH}/" "$DEST_CONN:${REAL_R_PATH}/"
done

# --- 6. RESTART ---
echo -e "\n✅ Transfer Complete."
echo -e "   Restarting containers..."
$SSH_CMD "$DEST_CONN" "docker start $R_ID"
docker start "$L_ID"

echo -e "\n🎉 ${GREEN}Success!${NC}"