#!/usr/bin/env bash
set -e

EXIT_OK=0
EXIT_NOT_SUPPORTED=1
EXIT_ERROR=1

TEDGE_CONFIG_DIR=${TEDGE_CONFIG_DIR:-/etc/tedge}
FILE="${FILE:-}"
MODULE_NAME="${MODULE_NAME:-}"
MODULE_VERSION="${MODULE_VERSION:-}"
MAPPER="${MAPPER:-local}"
PRESERVE_CONFIG_ON_DELETE="${PRESERVE_CONFIG_ON_DELETE:-1}"
MAPPERS_BASE_DIR="$TEDGE_CONFIG_DIR/mappers"

PARAMS_FILE="params.toml"

usage() {
    cat <<EOT
flow software management plugin

SUBCOMMANDS

 $0 prepare
 $0 install <MODULE_NAME> [--mapper <STRING>] [--module-version <STRING>] [--file <PATH>]
 $0 remove <MODULE_NAME> [--mapper <STRING>] [--module-version <STRING>]
 $0 list
 $0 finalize

ARGUMENTS

 --name <STRING>        Flow name. If not provided then the filename will be used
 --mapper <STRING>      Mapper name where the flow should be installed. Defaults to 'local'
 --file <PATH>          File path
EOT
}

POSITIONAL_ARGS=()
while [ $# -gt 0 ]; do
    case "$1" in
        --module-version)
            MODULE_VERSION="$2"
            shift
            ;;
        --file)
            FILE="$2"
            shift
            ;;
        --mapper)
            MAPPER="$2"
            shift
            ;;
        --help|-h)
            usage
            exit 0
            ;;
        --*|-*)
            echo "Ignoring unknown flag. '$1'" >&2
            shift
            ;;
        *)
            POSITIONAL_ARGS+=("$1")
            ;;
    esac
    shift
done

set -- "${POSITIONAL_ARGS[@]}"

if [ $# -ge 1 ]; then
    COMMAND="$1"
fi

if [ $# -ge 2 ]; then
    MODULE_NAME="$2"
fi

MAPPER_DIR="$TEDGE_CONFIG_DIR/mappers/$MAPPER/flows"
MAPPER_NAME=

list() {
    find "$MAPPERS_BASE_DIR/" -maxdepth 1 -type d | while read -r CURRENT_MAPPER_DIR; do
        name=$(basename "$CURRENT_MAPPER_DIR")
        if [ "$name" != mappers ]; then
            list_for_mapper "$name"
        fi
    done
}

list_for_mapper() {
    MAPPER_PREFIX=
    MAPPER_NAME=
    if [ $# -ge 1 ]; then
        MAPPER_NAME="$1"
        MAPPER_DIR="$MAPPERS_BASE_DIR/$MAPPER_NAME/flows"
        MAPPER_PREFIX="$MAPPER_NAME/"
    fi

    if [ ! -d "$MAPPER_DIR" ]; then
        echo "Flow directory does not exist. path=$MAPPER_DIR" >&2
        exit "$EXIT_OK"
    fi
    find "$MAPPER_DIR" -type f -name "*.toml" ! -name "$PARAMS_FILE" -a ! -name config.toml | while read -r CURRENT_FLOW_FILE; do
        # echo "found: $CURRENT_FLOW_FILE" >&2
        CURRENT_FLOW_DIR="$(dirname "$CURRENT_FLOW_FILE")"

        if [ "$CURRENT_FLOW_DIR" = "$MAPPER_DIR" ]; then
            # Flow is directly under the flows directory, so the name should be based on the filename
            # TODO: Should this be included as it is more for the built-in flows
            NAME=$(basename "$CURRENT_FLOW_FILE" .toml)
        else
            NAME=${CURRENT_FLOW_DIR#"$MAPPER_DIR/"}    
        fi
        VERSION=$(cd "$MAPPER_DIR" && awk -F'"' '/#? *version = / {print $2}' "$CURRENT_FLOW_FILE" ||:)
        printf '%s\t%s\n' "$MAPPER_PREFIX$NAME" "${VERSION:-0.0.0}"
    done
}

get_flows_dir() {
    mapper=
    full_module_name="$1"
    case "$full_module_name" in
        */*/*)
            mapper=$(echo "$full_module_name" | cut -d/ -f1)
            name=$(echo "$full_module_name" | cut -d/ -f2-)
            ;;
        */*)
            mapper=$(echo "$full_module_name" | cut -d/ -f1)
            name=$(echo "$full_module_name" | cut -d/ -f2-)
            ;;
        *)
            mapper="local"
            name="$full_module_name"
            ;;
    esac
    echo "$MAPPERS_BASE_DIR/${mapper}/flows/${name}"
}

install_flow() {
    if [ ! -f "$FILE" ]; then
        echo "ERROR: failed to install flow as the given file does not exist. path=$FILE" >&2
        exit "$EXIT_ERROR"
    fi

    if [ -z "$MODULE_NAME" ]; then
        echo "Reading flow name from filename" >&2
        MODULE_NAME=$(basename "$FILE" | cut -d. -f1 | cut -d: -f1)
    fi

    FLOW_DIR=$(get_flows_dir "$MODULE_NAME")
    
    case "$FILE" in
        http*://*)
            URL="$FILE"
            FILENAME=$(basename "$URL")
            FILE="/tmp/$FILENAME"
            wget -qO "$FILE" "$URL"
            ;;
        *.tar.gz)
            mkdir -p "$FLOW_DIR"
            echo "Unpacking flow (tar.gz) to $FLOW_DIR" >&2
            tar -xzf "$FILE" -C "$FLOW_DIR"
            ;;
        *.tar)
            mkdir -p "$FLOW_DIR"
            echo "Unpacking flow (tar) to $FLOW_DIR" >&2
            tar -xf "$FILE" -C "$FLOW_DIR"
            ;;
        *)
            # guess the file type
            mkdir -p "$FLOW_DIR"
            echo "Unpacking flow (assuming tar.gz) to $FLOW_DIR" >&2
            if ! tar -xzf "$FILE" -C "$FLOW_DIR"; then
                echo "Unpacking flow (assuming tar) to $FLOW_DIR" >&2
                tar -xf "$FILE" -C "$FLOW_DIR"
            fi
            ;;
    esac
}

remove_flow() {
    # plugin remove NAME [--module-version VERSION]
    FLOW_DIR=$(get_flows_dir "$MODULE_NAME")
    echo "Uninstalling flow: $FLOW_DIR"
    if [ -d  "$FLOW_DIR" ]; then
        case "$PRESERVE_CONFIG_ON_DELETE" in
            y|Y|YES|yes|1)
                # delete all files that aren't except the params file
                find "$FLOW_DIR" -type f ! -name "$PARAMS_FILE" -delete
                # delete all dirs which are empty
                rmdir --ignore-fail-on-non-empty "$FLOW_DIR/"** ||:
                rmdir --ignore-fail-on-non-empty "$FLOW_DIR" ||:
                ;;
            *)
                # remove entire directory (not preserving anything)
                rm -rf "$FLOW_DIR"
                ;;
        esac
    else
        echo "Nothing to do as the flow does not exist"
    fi
}

case "$COMMAND" in
    prepare)
        exit "$EXIT_OK"
        ;;
    list)
        list
        ;;
    update-list)
        exit "$EXIT_NOT_SUPPORTED"
        ;;
    install)
        install_flow
        ;;
    remove)
        remove_flow
        ;;
    finalize)
        exit "$EXIT_OK"
        ;;
    *)
        echo "Unknown command. name=$COMMAND" >&2
        exit "$EXIT_ERROR"
        ;;
esac