#!/bin/bash

MYID=$(id -u)
MYGRP=$(id -g)

_autocommandrun_volume() {
    command="$1"
    volume_name="$2"

    case "$command" in
        create)
            echo "Creating volume ${volume_name}"
            docker volume create ${volume_name}
            ;;
        nuke)
            echo "Nuking volume ${volume_name}"
            docker volume rm ${volume_name}
            ;;
        backup)
            local backup_folder="$3"
            echo "Backing up volume ${volume_name}"
            docker run --rm -v ${volume_name}:/volume -v ${backup_folder}:/backup debian bash -c "tar -czvf /backup/backup.tgz -C /volume . && chown -R $MYID:$MYGRP /backup"
            ;;
        restore)
            local backup_folder="$3"
            echo "Restoring volume ${volume_name}"
            docker volume rm ${volume_name}
            docker volume create ${volume_name}
            docker run --rm -v ${volume_name}:/volume -v ${backup_folder}:/backup debian bash -c "tar -xzvf /backup/backup.tgz -C /volume --strip-components=1"
            ;;
    esac
}   

_autocommandrun_path() {
    command="$1"
    path="$2"

    case "$command" in
        create)
            echo "Creating path ${path}"
            mkdir -p ${path}
            ;;
        nuke)
            echo "Nuking path ${path}"
            rm -rf ${path}
            ;;
        backup)
            local backup_folder="$3"
            echo "Backing up path ${path}"
            tar -czvf ${backup_folder}/backup.tgz -C ${path} .
            ;;
        restore)
            local backup_folder="$3"
            echo "Restoring path ${path}"
            tar -xzvf ${backup_folder}/backup.tgz -C ${path} --strip-components=1
            ;;
    esac
}

_autocommandrun_file() {
    command="$1"
    value="$2"

    case "$command" in
        create)
            ;;
        nuke)
            rm -f ${value}
            ;;
        backup)
            local backup_folder="$3"
            echo "Backing up file ${value}"
            # get filename from path
            local filename=$(basename ${value})
            cp ${value} ${backup_folder}/${filename}
            ;;
        restore)
            local backup_folder="$3"
            echo "Restoring file ${value}"
            local filename=$(basename ${value})
            cp ${backup_folder}/${filename} ${value}
            ;;
    esac
}

_autocommandparse() {
    # first argument is the command
    # if the command is backup or restore, then the last two arguments are the backup file and the temporary path
    # all other arguments are of form:
    # key=value
    # where key can be one of volume, path or file.
    # value is the path or volume name.

    # we iterate over the key=value arguments, and for each we call:
    #    autorun <command> <backupfile> <key> <value>

    local command="$1"
    shift

    local temp_path="$1"
    shift

    echo "autocommandparse: command=$command temp_path=$temp_path"

    # Extract the backup file and temp path (last two arguments)
    local args=("$@")
    local arg_count=${#args[@]}
    
    # Process all key=value pairs
    for ((i=0; i<$arg_count; i++)); do
        local pair="${args[$i]}"
        
        # Skip if not in key=value format
        if [[ "$pair" != *"="* ]]; then
            continue
        fi
        
        local key="${pair%%=*}"
        local value="${pair#*=}"

        # create backup folder unique to key/value.
        local bfolder="${key}_${value}"

        # remove any non-alphanumeric characters, that aren't dash or underscore from the bfile
        targetpath=""
        if [ ! "$temp_path" == "-" ]; then
            bfolder=$(echo "$bfolder" | tr -cd '[:alnum:]_-')
            mkdir -p ${temp_path}/${bfolder}
            targetpath="${temp_path}/${bfolder}"
        fi

        # Key must be one of volume, path or file
        case "$key" in
            volume)
                _autocommandrun_volume "$command" "$value" "$targetpath"
                ;;
            path)
                _autocommandrun_path "$command" "$value" "$targetpath"
                ;;
            file)
                _autocommandrun_file "$command" "$value" "$targetpath"
                ;;
            *)
                _die "Unknown key $key passed to auto${command}. We only support volume, path and file."
                ;;
        esac
    done
}


autocreate() {
    _autocommandparse create "-" "$@"
}


autonuke() {
    _autocommandparse nuke "-" "$@"
}


autobackup() {
    local backup_file="$1"
    shift
    local temp_path="$1"    
    shift

    [ -f "$backup_file" ] && _die "Backup file $backup_file already exists"
    [ -d "$temp_path" ] || _die "Temp path $temp_path does not exist"

    local backup_temp_path="$temp_path/backup"

    mkdir -p "$backup_temp_path"
    echo "_autocommandparse [backup] [$backup_temp_path] [$@]"
    _autocommandparse backup "$backup_temp_path" "$@"

    tar zcvf "$backup_file" -C "$backup_temp_path" .
}


autorestore() {
    local backup_file="$1"
    shift
    local temp_path="$1"
    shift

    [ -f "$backup_file" ] || _die "Backup file $backup_file does not exist"
    [ -d "$temp_path" ] || _die "Temp path $temp_path does not exist"

    local restore_temp_path="$temp_path/restore"

    mkdir -p "$restore_temp_path"
    tar zxvf "$backup_file" -C "$restore_temp_path" --strip-components=1

    _autocommandparse restore "$restore_temp_path" "$@"
}