#!/bin/sh

umask 077

dir="$(mktemp -d "${TMPDIR:-/tmp}/hledger-vega.XXXXXXXXXX")"
trap "rm -r $dir" EXIT

datasetsdir=./datasets
chartsdir=./charts
outdir=./charts

log(){
    echo >&2 $*   # stderr to fit with make_chart_data
}

# initialize a semaphore with a given number of tokens
open_sem(){
    mkfifo $dir/pipe-$$
    exec 3<>$dir/pipe-$$
    rm $dir/pipe-$$
    local i=$1
    for((;i>0;i--)); do
        printf %s 000 >&3
    done
}

# run the given command asynchronously and pop/push tokens
run_with_lock(){
    local x
    # this read waits until there is something to read
    read -u 3 -n 3 x && ((0==x)) || exit $x
    (
     ( "$@"; )
    # push the return code of the command to the semaphore
    printf '%.3d' $? >&3
    )#&  # comment the & to run single threaded, for clearer logging
}

# Create the data directory if it doesn't exist
mkdir -p "$outdir"

# Use 4 jobs
N=4
open_sem $N

hledger_with_name() {
    local namewithext="$(basename "$1")"
    local name="${namewithext%.*}"
    log "hledger balance --output-format=csv --layout=tidy --daily @"$1"" # > "$dir/$name.csv""
    hledger balance --output-format=csv --layout=tidy --daily @"$1" > "$dir/$name.csv"
    if [[ $(wc -l < "$dir/$name.csv") -le 1 ]]; then
      log "Warning: hledger produced no output from \"$1\""
    fi
}

make_chart_data() {
    local namewithext="$(basename "$1")"
    local name="${namewithext%.*}"
    local IFS=";"
    local first=1
    log "$outdir/$name.csv:"
    while read -a line; do
        local csv="$dir/${line[0]}.csv"
        local label="${line[1]}"
	log "    $(basename "$csv")"
        {
          if [[ $first -eq 1 ]]; then
              cat "$csv"
          else
              tail -n "+2" "$csv"
          fi
        } | sed -e "s/^\"...\"/\"$label\"/"
        first=0
    done < "$1" \
         > "$outdir/$name.csv"
}

log "Generating hledger data sets (in $dir):"
for args in "$datasetsdir"/*.args; do
    run_with_lock hledger_with_name "$args"
done

wait

log "Combining data sets into chart data (in $chartsdir):"
for chart in "$chartsdir"/*.datasets; do
    run_with_lock make_chart_data "$chart"
done

wait