#!/bin/bash
# Version: 1.3.0
# ==============================================================================
# SAP HANA Schema Management Tool (hanatool.sh)
#
# A command-line utility to quickly export, restore, or restore-and-rename
# a SAP HANA schema.
# ==============================================================================

# --- Default Settings ---
HDBSQL_PATH="/usr/sap/hdbclient/hdbsql"
COMPRESS=false
THREADS=0 # 0 means auto-calculate later
DRY_RUN=false
NTFY_TOKEN=""

# --- Help/Usage Function ---
usage() {
    echo "SAP HANA Schema Management Tool"
    echo ""
    echo "Usage: $0 [USER_KEY] [ACTION] [SCHEMA_NAME] [PATH] [OPTIONS]"
    echo "       $0 [USER_KEY] restore-rename [SCHEMA_NAME] [NEW_SCHEMA_NAME] [PATH] [OPTIONS]"
    echo ""
    echo "Actions:"
    echo "  export          Export a schema to a specified path."
    echo "  restore         Restore a schema from a specified path."
    echo "  restore-rename  Restore a schema from a path to a new schema name."
    echo ""
    echo "Arguments:"
    echo "  USER_KEY          The user key from hdbuserstore for DB connection."
    echo "  SCHEMA_NAME       The name of the source schema."
    echo "  NEW_SCHEMA_NAME   (Required for restore-rename only) The target schema name."
    echo "  PATH              The file system path for the export/import data."
    echo ""
    echo "Options:"
    echo "  -t, --threads N   Specify the number of threads. Defaults to half of system cores."
    echo "  -c, --compress    Enable tar.gz compression for exports and decompression for imports."
    echo "  -n, --dry-run     Show what commands would be executed without running them."
    echo "  --ntfy <token>    Send a notification via ntfy.sh upon completion/failure."
    echo "  --hdbsql <path>   Specify a custom path for the hdbsql executable."
    echo "  -h, --help        Show this help message."
    echo ""
    echo "Examples:"
    echo "  # Export MYSCHEMA and send a notification on completion"
    echo "  $0 MYKEY export MYSCHEMA /hana/backups -c --ntfy tk_xxxxxxxxxxxx"
    echo ""
    echo "  # Restore MYSCHEMA as MYSCHEMA_TEST using a custom hdbsql path"
    echo "  $0 MYKEY restore-rename MYSCHEMA MYSCHEMA_TEST /hana/backups/temp_export --hdbsql /sap/custom/hdbsql"
}

# --- Notification Function ---
send_notification() {
    local message="$1"
    if [[ -n "$NTFY_TOKEN" && "$DRY_RUN" == "false" ]]; then
        echo "ℹ️  Sending notification..."
        curl -s -H "Authorization: Bearer $NTFY_TOKEN" -d "$message" https://ntfy.technopunk.space/sap > /dev/null
    elif [[ -n "$NTFY_TOKEN" && "$DRY_RUN" == "true" ]]; then
        echo "[DRY RUN] Would send notification: curl -H \"Authorization: Bearer ...\" -d \"$message\" https://ntfy.technopunk.space/sap"
    fi
}

# --- Argument Parsing ---
POSITIONAL_ARGS=()
while [[ $# -gt 0 ]]; do
    case $1 in
        -t|--threads)
            THREADS="$2"
            shift 2
            ;;
        -c|--compress)
            COMPRESS=true
            shift
            ;;
        -n|--dry-run)
            DRY_RUN=true
            shift
            ;;
        --ntfy)
            NTFY_TOKEN="$2"
            shift 2
            ;;
        --hdbsql)
            HDBSQL_PATH="$2"
            shift 2
            ;;
        -h|--help)
            usage
            exit 0
            ;;
        *)
            POSITIONAL_ARGS+=("$1") # save positional arg
            shift
            ;;
    esac
done
set -- "${POSITIONAL_ARGS[@]}" # restore positional parameters

# Assign positional arguments to variables
USER_KEY="$1"
ACTION="$2"
SCHEMA_NAME="$3"

# --- Main Logic ---

if [[ "$DRY_RUN" == "true" ]]; then
    echo "⚠️  --- DRY RUN MODE ENABLED --- ⚠️"
    echo "No actual commands will be executed."
    echo "-------------------------------------"
fi

# Check for hdbsql executable
if [[ ! -x "$HDBSQL_PATH" ]]; then
    echo "❌ Error: hdbsql not found or not executable at '${HDBSQL_PATH}'"
    exit 1
fi

# Calculate default threads if not specified
if [[ "$THREADS" -eq 0 ]]; then
    TOTAL_THREADS=$(nproc --all)
    THREADS=$((TOTAL_THREADS / 2))
    if [[ "$THREADS" -eq 0 ]]; then
        THREADS=1
    fi
    echo "ℹ️  Auto-detected threads to use: ${THREADS}"
fi

# Execute action based on user input
case "$ACTION" in
    export)
        TARGET_PATH="$4"
        if [[ -z "$USER_KEY" || -z "$SCHEMA_NAME" || -z "$TARGET_PATH" ]]; then
            echo "❌ Error: Missing arguments for 'export' action."
            usage
            exit 1
        fi
        
        echo "⬇️  Starting schema export..."
        echo "   - User Key:   ${USER_KEY}"
        echo "   - Schema:     ${SCHEMA_NAME}"
        echo "   - Path:       ${TARGET_PATH}"
        echo "   - Compress:   ${COMPRESS}"
        echo "   - Threads:    ${THREADS}"

        EXPORT_DIR="$TARGET_PATH"
        if [[ "$COMPRESS" == "true" ]]; then
            if [[ "$DRY_RUN" == "true" ]]; then
                 EXPORT_DIR="${TARGET_PATH}/export_${SCHEMA_NAME}_DRYRUN_TEMP"
            else
                EXPORT_DIR=$(mktemp -d "${TARGET_PATH}/export_${SCHEMA_NAME}_XXXXXXXX")
            fi
            echo "ℹ️  Using temporary export directory: ${EXPORT_DIR}"
        fi

        if [[ "$DRY_RUN" == "true" ]]; then
            echo "[DRY RUN] Would create directory: mkdir -p \"$EXPORT_DIR\""
        else
            mkdir -p "$EXPORT_DIR"
        fi
        
        QUERY="EXPORT \"${SCHEMA_NAME}\".\"*\" AS BINARY INTO '${EXPORT_DIR}' WITH REPLACE THREADS ${THREADS};"
        
        EXIT_CODE=0
        if [[ "$DRY_RUN" == "true" ]]; then
            echo "[DRY RUN] Would execute hdbsql: \"$HDBSQL_PATH\" -U \"$USER_KEY\" \"$QUERY\""
        else
            "$HDBSQL_PATH" -U "$USER_KEY" "$QUERY" > /dev/null 2>&1
            EXIT_CODE=$?
        fi

        if [[ "$EXIT_CODE" -eq 0 ]]; then
            echo "✅ Successfully exported schema '${SCHEMA_NAME}' to '${EXPORT_DIR}'."
            if [[ "$COMPRESS" == "true" ]]; then
                ARCHIVE_FILE="${TARGET_PATH}/${SCHEMA_NAME}_$(date +%Y%m%d_%H%M%S).tar.gz"
                echo "🗜️  Compressing files to '${ARCHIVE_FILE}'..."
                
                TAR_EXIT_CODE=0
                if [[ "$DRY_RUN" == "true" ]]; then
                    echo "[DRY RUN] Would execute tar: tar -czf \"$ARCHIVE_FILE\" -C \"$(dirname "$EXPORT_DIR")\" \"$(basename "$EXPORT_DIR")\""
                else
                    tar -czf "$ARCHIVE_FILE" -C "$(dirname "$EXPORT_DIR")" "$(basename "$EXPORT_DIR")"
                    TAR_EXIT_CODE=$?
                fi

                if [[ "$TAR_EXIT_CODE" -eq 0 ]]; then
                    echo "✅ Successfully created archive."
                    echo "🧹 Cleaning up temporary directory..."
                    if [[ "$DRY_RUN" == "true" ]]; then
                        echo "[DRY RUN] Would remove temp directory: rm -rf \"$EXPORT_DIR\""
                    else
                        rm -rf "$EXPORT_DIR"
                    fi
                else
                    echo "❌ Error: Failed to create archive from '${EXPORT_DIR}'."
                fi
            fi
            send_notification "✅ Export of schema '${SCHEMA_NAME}' completed successfully."
        else
            echo "❌ Error: Failed to export schema '${SCHEMA_NAME}' (hdbsql exit code: ${EXIT_CODE})."
            send_notification "❌ Export of schema '${SCHEMA_NAME}' FAILED."
            if [[ "$COMPRESS" == "true" && "$DRY_RUN" == "false" ]]; then rm -rf "$EXPORT_DIR"; fi
        fi
        ;;

    restore|restore-rename)
        if [[ "$ACTION" == "restore" ]]; then
            SOURCE_PATH="$4"
            NEW_SCHEMA_NAME=""
            if [[ -z "$USER_KEY" || -z "$SCHEMA_NAME" || -z "$SOURCE_PATH" ]]; then
                echo "❌ Error: Missing arguments for 'restore' action."
                usage
                exit 1
            fi
        else # restore-rename
            NEW_SCHEMA_NAME="$4"
            SOURCE_PATH="$5"
            if [[ -z "$USER_KEY" || -z "$SCHEMA_NAME" || -z "$NEW_SCHEMA_NAME" || -z "$SOURCE_PATH" ]]; then
                echo "❌ Error: Missing arguments for 'restore-rename' action."
                usage
                exit 1
            fi
        fi

        echo "⬆️  Starting schema import..."
        echo "   - User Key:   ${USER_KEY}"
        echo "   - Source Schema: ${SCHEMA_NAME}"
        if [[ -n "$NEW_SCHEMA_NAME" ]]; then
        echo "   - Target Schema: ${NEW_SCHEMA_NAME}"
        fi
        echo "   - Path:       ${SOURCE_PATH}"
        echo "   - Compress:   ${COMPRESS}"
        echo "   - Threads:    ${THREADS}"
        
        IMPORT_DIR="$SOURCE_PATH"
        if [[ "$COMPRESS" == "true" ]]; then
            if [[ ! -f "$SOURCE_PATH" && "$DRY_RUN" == "false" ]]; then
                echo "❌ Error: Source path '${SOURCE_PATH}' is not a valid file for compressed import."
                exit 1
            fi

            if [[ "$DRY_RUN" == "true" ]]; then
                IMPORT_DIR="/tmp/import_${SCHEMA_NAME}_DRYRUN_TEMP"
            else
                IMPORT_DIR=$(mktemp -d "/tmp/import_${SCHEMA_NAME}_XXXXXXXX")
            fi

            echo "ℹ️  Decompressing to temporary directory: ${IMPORT_DIR}"
            
            TAR_EXIT_CODE=0
            if [[ "$DRY_RUN" == "true" ]]; then
                echo "[DRY RUN] Would decompress archive: tar -xzf \"$SOURCE_PATH\" -C \"$IMPORT_DIR\" --strip-components=1"
            else
                tar -xzf "$SOURCE_PATH" -C "$IMPORT_DIR" --strip-components=1
                TAR_EXIT_CODE=$?
            fi

            if [[ "$TAR_EXIT_CODE" -ne 0 ]]; then
                echo "❌ Error: Failed to decompress '${SOURCE_PATH}'."
                if [[ "$DRY_RUN" == "false" ]]; then rm -rf "$IMPORT_DIR"; fi
                exit 1
            fi
        fi

        if [[ ! -d "$IMPORT_DIR" && "$DRY_RUN" == "false" ]]; then
            echo "❌ Error: Import directory '${IMPORT_DIR}' does not exist."
            exit 1
        fi

        QUERY_RENAME_PART=""
        if [[ "$ACTION" == "restore-rename" ]]; then
            QUERY_RENAME_PART="WITH RENAME SCHEMA \"${SCHEMA_NAME}\" TO \"${NEW_SCHEMA_NAME}\""
        fi

        QUERY="IMPORT \"${SCHEMA_NAME}\".\"*\" AS BINARY FROM '${IMPORT_DIR}' ${QUERY_RENAME_PART} WITH IGNORE EXISTING THREADS ${THREADS};"

        EXIT_CODE=0
        if [[ "$DRY_RUN" == "true" ]]; then
            echo "[DRY RUN] Would execute hdbsql: \"$HDBSQL_PATH\" -U \"$USER_KEY\" \"$QUERY\""
        else
            "$HDBSQL_PATH" -U "$USER_KEY" "$QUERY" > /dev/null 2>&1
            EXIT_CODE=$?
        fi

        local target_schema_name="${NEW_SCHEMA_NAME:-$SCHEMA_NAME}"
        if [[ "$EXIT_CODE" -eq 0 ]]; then
            echo "✅ Successfully imported schema."
            send_notification "✅ ${ACTION} of schema '${SCHEMA_NAME}' to '${target_schema_name}' completed successfully."
        else
            echo "❌ Error: Failed to import schema (hdbsql exit code: ${EXIT_CODE})."
            send_notification "❌ ${ACTION} of schema '${SCHEMA_NAME}' to '${target_schema_name}' FAILED."
        fi

        if [[ "$COMPRESS" == "true" ]]; then
            echo "🧹 Cleaning up temporary directory..."
            if [[ "$DRY_RUN" == "true" ]]; then
                echo "[DRY RUN] Would remove temp directory: rm -rf \"$IMPORT_DIR\""
            else
                rm -rf "$IMPORT_DIR"
            fi
        fi
        ;;

    *)
        echo "❌ Error: Invalid action '${ACTION}'."
        usage
        exit 1
        ;;
esac

echo "✅ Process complete."