#!/bin/bash

trap "" SIGHUP SIGPIPE

if [ ! -d $HOME/dc ]; then mkdir $HOME/dc; fi
if [ ! -d $HOME/dc/done ]; then mkdir $HOME/dc/done; fi
if [ ! -d $HOME/dc/resume ]; then mkdir $HOME/dc/resume; fi
if [ ! -d $HOME/dc/users ]; then mkdir $HOME/dc/users; fi
exec 2>>$HOME/dc/filterlog
cd $HOME/dc

unset speedrecpath
IFS=: binpath=($PATH)
lepath=()
for dir in "${binpath[@]}"; do
    lepath=("${lepath[@]}" "${dir%/bin}/libexec")
done
for dir in "${lepath[@]}" /usr/libexec /usr/local/libexec; do
    if [ -x "${dir}/speedrec" ]; then
	speedrecpath="${dir}/speedrec"
    fi
done
if [ -z "$speedrecpath" ]; then
    echo "could not find speedrec - using cat instead" >&2
fi

maxsize=0
unset resfile
unset infofile
found=y
while [ -z "$resfile" -a "$found" = y ]; do
    unset found
    for file in resume/*.info; do
	if [ ! -r "$file" ]; then continue; fi
	. "$file"
	if [ "$filesize" -eq "$2" ]; then
	    thisfile="${file%.info}"
	    if [ ! -e "${thisfile}.lock" ]; then
		size="$(wc -c <"$thisfile")"
		found=y
		if [ "$size" -gt "$maxsize" ]; then
		    maxsize="$size"
		    resfile="$thisfile"
		    infofile="$file"
		fi
	    fi
	fi
    done
    if [ -n "$resfile" ]; then
	if ! locktouch "${resfile}.lock"; then
	    unset resfile
	fi
    fi
done

unset "${!dcarg_@}"
if [ -n "$resfile" ]; then
    . "${resfile}.info"
fi

origname="$1"
shift
filesize="$1"
shift
peername="$1"
shift
while [ $# -gt 1 ]; do
    rec="$1"
    shift
    val="$1"
    shift
    declare "dcarg_$rec"="$val"
done

if [ -z "$resfile" ]; then
    resfile="$(mktemp resume/resXXXXXX)"
    chmod 644 "$resfile"
    maxsize=0
    >"${resfile}.lock"
fi
declare -p origname filesize "${!dcarg_@}" >"${resfile}.info"

echo "resume $maxsize" 2>/dev/null   # Avoid EPIPE warning if the server has already closed the transfer.

if [ -z "$speedrecpath" ]; then
    speedrec=(cat)
else
    speedrec=("$speedrecpath" "$HOME/dc/users/$(tr / _ <<<"$peername")")
    peerfile="$(tr / _ <<<"$peername")"
fi
if ! which tthsum >/dev/null 2>&1; then
    tthsum=(cat)
else
    tthsum=(tthsum -6 -F 3 -s "${resfile}.tthstate" -f)
fi
"${speedrec[@]}" | "${tthsum[@]}" 3>"${resfile}.tthfinal" >>"$resfile"

size="$(wc -c <"$resfile")"

if [ "$size" -eq 0 ]; then
    rm -f "$resfile" "${resfile}.info" "${resfile}.lock" "${resfile}.tthstate" "${resfile}.tthfinal"
    exit 1
fi

if [ "$size" -lt "$filesize" ]; then
    rm -f "${resfile}.lock" "${resfile}.tthfinal"
    exit 1   # Exit code != 0 means restart transfer
fi

tth="$(cat "${resfile}.tthfinal")"
if [ -z "$tth" ]; then unset tth; fi

rm -f "${resfile}.info" "${resfile}.lock" "${resfile}.tthstate" "${resfile}.tthfinal"

destdir="$HOME/dc/done"

newname="$destdir"/"$origname"
if [ -e "$newname" ]; then
    newname="$(mktemp "${newname}XXXXXX")"
fi
mv "$resfile" "$newname"
if [ -x $HOME/dc/complete ]; then
    export "${!dcarg_@}" tth filesize
    exec $HOME/dc/complete "$newname"
fi
exit 0