#!/bin/bash

_ak_fs_return_hash_path(){
    hashpath="$(echo -n "$1" |sed 's/./&\//g;s/\/$//g')"
    echo -n "$hashpath"
}

_ak_fs_return_hash_dir(){
    hashdir="$(echo -n "$1" | sed -e 's/./&\//g' | grep '\(./\)\{128\}' | sed -e 's/..$//')"
    echo -n "$hashdir"
}

_ak_fs_verify_input_is_hash(){
    if [ ! -z "$1" ] && echo "$1" | grep '[0123456789abcdef]\{128\}' > /dev/null 2>&1
    then
        return 0
    else
        echo "no hash?!" >&2
        exit 1
    fi
}

_ak_fs_create_dir_for_hash(){
    _ak_fs_verify_input_is_hash $2
    if [ ! -z $1 ] && [ ! -z $2 ] && [ -n "$1" ] && [ -n "$2" ]
    then
        mkdir -p "$1/$(_ak_fs_return_hash_dir $2)"
    fi
}

# Append last chk if not even number
_ak_fs_appendLastIfNotEven(){
    if [ "$(( $(wc -l "$1" | awk '{ print $1 }') % 2))" -ne 0 ]
    then
        tail -n 1 "$1" >> "$1"
    fi
}

_ak_fs_import(){
    #
    # The concept is bit more complicated now
    #
    # 1. For a given file we split in 4KB files inside a temporary directory
    #
    # 2. We then create a map file and a merkle tree containing the resulted files
    # and their sha512sum.
    #
    # 3. We move the splitted files to our $CHKDIR named after their checksums
    #
    # 4. We move the merkle tree pairs to $MERKLEDIR
    #
    # We ultimately want to be seeding the file so
    #
    # 4. We append the checksum of the original file with its name into the map file
    #
    # 5. We rename the map file after its checksum and move it to maps directory
    #
    # 6. We are done!
    #

    # The directory where the chunked data will be living at
    CHKDIR="$AK_WORKDIR/ftr"
    # The directory for the map files so we can reconstruct the file
    FILEMAPSDIR="$AK_WORKDIR/fmp"
    # Merkle tree file/references
    MERKLEDIR="$AK_WORKDIR/fmrk"
    # A temporary root dir to work on
    TEMPORARYDIR="$(_ak_make_temp_directory)"
    # A subdir to split the files there
    TECHDIR="$TEMPORARYDIR/chks"
    # A pin point to return from where we came from
    CURRENTDIR="$(pwd)"

    # Checking directories and create them if necessary
    # rm -rf $TEMPORARYDIR

    # TECHDIR
    if [ ! -d "$TECHDIR" ]
    then
        mkdir -p "$TECHDIR"
        if [ $? -eq 0 ]
        then
            _ak_log_info "Folder $TECHDIR created!"
        else
            _ak_log_error "Problem occured while creating $TECHDIR"
            exit 1
        fi
    else
        _ak_log_info "Temp dir found"
    fi

    # FILEMAPSDIR
    if [ ! -d "$FILEMAPSDIR" ]
    then
        mkdir -p "$FILEMAPSDIR"
        if [ $? -eq 0 ]
        then
            _ak_log_info "Folder $FILEMAPSDIR created!"
        else
            _ak_log_error "Problem occured while creating $FILEMAPSDIR"
            exit 1
        fi
    else
        _ak_log_info "Mapsdir found"
    fi

    # CHKDIR
    if [ ! -d "$CHKDIR" ]
    then
        mkdir -p "$CHKDIR"
        if [ $? -eq 0 ]
        then
            _ak_log_info "Folder $CHKDIR created!"
        else
            _ak_log_error "Problem occured while creating $CHKDIR"
            exit 1
        fi
    else
        _ak_log_info "Workdir found"
    fi

    # MERKLEDIR
    if [ ! -d "$MERKLEDIR" ]
    then
        mkdir -p "$MERKLEDIR"
        if [ $? -eq 0 ]
        then
            _ak_log_info "Folder $MERKLEDIR created!"
        else
            _ak_log_error "Problem occured while creating $MERKLEDIR"
            echo "ERROR Can't create $MERKLEDIR"
            exit 1
        fi
    else
        _ak_log_info "Workdir found"
    fi
    if [ ! -f "$1" ]
    then
        _ak_log_error "File $1 not found"
        exit 1
    else
        # TODO
        # Side hustle, save the original hash and original filename
        # This won't be expected in general
        # The idea is:
        # sha256sum as quick pointer to root of the tree
        #
        _ak_log_info "Storing original hash of $1 along with its name"
        sha512sum "$1" > $TEMPORARYDIR/3rd_gen_map
        _ak_log_info "Encoding to base64"
        base64 $1 > file
        FILE="file"
    fi

    # Uncomment next line in case you want to debug the resulting script as well
    # echo 'set -xe' > $TEMPORARYDIR/cmd_queue.sh

    # We get the SHA512 hash for the $FILE given
    CHECKSUM=$(sha512sum "$FILE"|awk '{print $1}')
    FILE_SIZE="$(du -b $FILE | awk '{ print $1 }')"
    if [ $FILE_SIZE -lt 4097 ]
    then
        cp $FILE "$TECHDIR/$(basename "$FILE")-00000000000000000000000000000000000000000000000000.chk"
    else
        FACTOR=1024
        while [ $(( $FILE_SIZE / $FACTOR )) -gt 250 ]
        do
            FACTOR=$(( $FACTOR * 2 ))
        done
        _ak_log_info "Gonna split in $FACTOR size"
        sleep 30
        # We split the file into 4*1024 bytes and output the chunks into TECHDIR
        split -a 50 -b $FACTOR --additional-suffix ".chk" -d "$FILE" "$TECHDIR/$(basename "$FILE")-"
    fi
    _ak_log_info "File done splitting"

    # We go over there...
    cd $TECHDIR
    #set -xe
    # We get every chunks' SHA512 and we craft a script to rename the chunks and
    # move them to CHKDIR
    for file in $TEMPORARYDIR/chks/*
    do
        sha512sum $file >> $TEMPORARYDIR/map
    done
    _ak_fs_appendLastIfNotEven "$TEMPORARYDIR/map"
    # Figure out how many times we need to pack
    totalChunks=`grep 'chk' $TEMPORARYDIR/map | wc -l`
    temp="$totalChunks"
    timesRan=0
    while [ $temp -ne 1 ]
    do
        temp=`expr $temp / 2`
        timesRan=`expr $timesRan + 1`
    done
    _ak_log_debug "Ran $timesRan times"
    _ak_log_debug "Total chunks $totalChunks"

    workingIndex="$TEMPORARYDIR/map"
    c=$timesRan
    while [ $c -ne 0 ]
    do
        a=1
        _ak_log_debug "Level: $c, will work on $totalChunks chunks"
        while [[ "$a" -lt "$totalChunks" ]]
        do
            b=`expr "$a" + 1`
            sed -n "$a"p "$workingIndex" | awk '{ print $1 }' >> level.$c.pair.$a-$b
            sed -n "$b"p "$workingIndex" | awk '{ print $1 }' >> level.$c.pair.$a-$b
            shaSum="$(sha512sum level.$c.pair.$a-$b | awk '{ print $1 }')"
            mkdir -p $MERKLEDIR/$(_ak_fs_return_hash_dir $shaSum)
            cp level.$c.pair.$a-$b $MERKLEDIR/$(_ak_fs_return_hash_path $shaSum)
            sha512sum level.$c.pair.$a-$b | awk '{ print $1 }' >> level.$c.map
            a=`expr "$a" + 2`
        done
        workingIndex="level.$c.map"
        _ak_fs_appendLastIfNotEven "$workingIndex"
        shaSum=`sha512sum $workingIndex | awk '{ print $1 }'`
        mkdir -p $MERKLEDIR/$(_ak_fs_return_hash_dir $shaSum)
        cp $workingIndex $MERKLEDIR/$(_ak_fs_return_hash_path $shaSum)
    #    cp $workingIndex $MERKLEDIR/$shaSum
        totalChunks=`cat $workingIndex | wc -l`
        c=`expr $c - 1`
    done

    if [ -f level.1.map ]
    then
        sha512sum level.1.map
        sha512sum level.1.map >> $TEMPORARYDIR/3rd_gen_map
    else
        echo error
        exit 1
    fi

    # Reset file with uniq
    cat $TEMPORARYDIR/map | uniq > $TEMPORARYDIR/map2
    cat $TEMPORARYDIR/map2 > $TEMPORARYDIR/map
    rm $TEMPORARYDIR/map2

    counter=0
    while IFS="" read -r p || [ -n "$p" ]
    do
        printf "mv %s %s/%s\n" "$(echo $p | awk '{ print $2 }')" "$CHKDIR" "$(echo $p | awk '{ print $1 }')" >> $TEMPORARYDIR/cmd_queue.sh
        counter=`expr "$counter" + 1`
    done < $TEMPORARYDIR/map

    # We run the crafted script
    sh $TEMPORARYDIR/cmd_queue.sh

    # and we delete it
    rm $TEMPORARYDIR/cmd_queue.sh

    # We inform the map about the original $FILE name and SHA512
    echo "$CHECKSUM  $(basename "$FILE")" >> $TEMPORARYDIR/map

    # We get the SHA512 hash of the resulted map file
    MAPFILEHASH="$(sha512sum $TEMPORARYDIR/map | awk '{ print $1 }')"

    # and we rename it with it and move it to FILEMAPSDIR
    `sha512sum $TEMPORARYDIR/map | awk '{print "mv " $2 " '$FILEMAPSDIR/'" $1}'`

    mp512p="$(sha512sum $TEMPORARYDIR/3rd_gen_map | awk '{print $1}')"
    mv $TEMPORARYDIR/3rd_gen_map $FILEMAPSDIR/$mp512p

    # We remove the TEMPORARYDIR
    rm -rf $TEMPORARYDIR

    # and print the MAPFILEHASH
    echo "$mp512p"

}

_ak_fs_find_depth(){
    currentNode="$1"
    pathToNode="$fmrk/$(_ak_fs_return_hash_path $currentNode)"
    if [ -f $pathToNode ] && [ "$(du -b $pathToNode | awk '{print $1}')" == "258" ]
    then
        fileHead="$(head -n 1 $pathToNode)"
        counter="$(expr $counter + 1)"
        _ak_fs_find_depth "$fileHead"
    elif [ ! -f $pathToNode ]
    then
        printf "%s" "$counter" > depth
    else
        exit 111
        # Try to download stuff
        #        wget -s $remoteMrk/$currentNode -O $fmrk/$currentNode
        #        if [ $? -ne 0 ]
        #        then
        #            exit 111
        #        fi
        #        _ak_fs_find_depth "$currentNode"
    fi
}

_ak_fs_cat(){
    if [ -z $1 ]
    then
        echo "Please provide a SHA512 hash"
        exit 1
    fi
    echo $1 | grep "[0123456789abcdef]\{128\}"
    if [ $? -ne 0 ]
    then
        echo "Look, I asked for a SHA512 hash, please try again"
        exit 1
    fi
    treeRootHash="$1"
    fmrk="$AK_WORKDIR/fmrk"
    ftr="$AK_WORKDIR/ftr"
    # Enter temp folder
    TEMPASSIN="$(_ak_make_temp_directory)"
    cd $TEMPASSIN
    currentNode="$treeRootHash"
    counter=0
    printf "%s" "$currentNode" > workspace.0
    _ak_fs_find_depth "$currentNode"
    depth="$(expr `cat depth` + 1)"
    counter="0"
    printf "%s" "$depth"
    if [ -f output ]
    then
        rm output
    fi
    touch output
    while [ "$counter" != "$depth" ]
    do
        _ak_log_debug "Entering loop... $counter $depth"
        while IFS="" read -r p || [ -n "$p" ]
        do
            nextLevel="$(expr $counter + 1)"
            if [ "$p" == "" ]
            then
                echo hi
            else
                expectedPath="$fmrk/$(_ak_fs_return_hash_path $p)"
                if [ -f $expectedPath ]
                then
                    if [ "$(head -n 1 $expectedPath)" == "$(tail -n 1 $expectedPath)" ]
                    then
                        head -n 1 $expectedPath >> workspace.$nextLevel
                    else
                        cat $expectedPath >> workspace.$nextLevel
                    fi
                elif [ -f $ftr/$p ]
                then
                    cat $ftr/$p >> output
                fi
            fi
        done < workspace.$counter
        counter="$(expr $counter + 1)"
    done

    base64 -d output
    _ak_log_info "Recreation of $treeRootHash succeeded!"
}

_ak_fs_export(){
    if [ -z $1 ]
    then
        _ak_log_error "Please provide a SHA512 hash"
        exit 1
    fi
    if [ -z $2 ]
    then
        _ak_log_error "Please an output filename"
        exit 2
    fi
    outputFilename="$2"
    echo $1 | grep "[0123456789abcdef]\{128\}"
    if [ $? -ne 0 ]
    then
        _ak_log_error "Look, I asked for a SHA512 hash, please try again"
        exit 1
    fi
    _ak_fs_export "$1" > $outputFilename
}