#!/usr/bin/env nix-shell
#!nix-shell -i bash -p nar-serve wget nix-locate man xz gzip bzip2
set -euo pipefail

N_WORKERS=4

# TODO: allow to pick which nix-index to fetch and use

# https://github.com/numtide/nar-serve
HTTP_ADDR=localhost:8383 nar-serve &
NAR_SERVE_PID=$!
trap "set -x; kill $NAR_SERVE_PID" EXIT SIGHUP SIGINT SIGQUIT
let N_WORKERS+=1

while read attrpath size type storepath _; do
    outpath="data/$attrpath/$(cut -d/ -f7- <<<"$storepath")"
    test -s "$outpath" || (
        mkdir -vp "$(dirname "$outpath")"
        set -x
        wget http://localhost:8383"$storepath" -O "$outpath" || true
    )

    if [[ ! -s "$outpath" ]]; then
        continue
    fi

    (
        if [[ "$outpath" =~ .*\.gz$ ]]; then
            htmlpath="html/$attrpath/$(cut -d/ -f7- <<<"$storepath" | rev | cut -d. -f2- | rev).html"
            test -s "$htmlpath" || ( set -x;
                mkdir -p "$(dirname "$htmlpath")"; man --html=cat <(zcat "$outpath") > "$htmlpath"
            )
        elif [[ "$outpath" =~ .*\.bz2$ ]]; then
            htmlpath="html/$attrpath/$(cut -d/ -f7- <<<"$storepath" | rev | cut -d. -f2- | rev).html"
            test -s "$htmlpath" || ( set -x;
                mkdir -p "$(dirname "$htmlpath")"; man --html=cat <(bzcat "$outpath") > "$htmlpath"
            )
        elif [[ "$outpath" =~ .*\.xz$ ]]; then
            htmlpath="html/$attrpath/$(cut -d/ -f7- <<<"$storepath" | rev | cut -d. -f2- | rev).html"
            test -s "$htmlpath" || ( set -x;
                mkdir -p "$(dirname "$htmlpath")"; man --html=cat <(xzcat "$outpath") > "$htmlpath"
            )
        else
            htmlpath="html/$attrpath/$(cut -d/ -f7- <<<"$storepath").html"
            test -s "$htmlpath" || ( set -x;
                mkdir -p "$(dirname "$htmlpath")"; man --html=cat "$outpath" > "$htmlpath"
            )
        fi
    ) &

    while [[ $(jobs -p | wc -l) -ge $N_WORKERS ]]; do
        wait -n < <(jobs -p) || true
    done

done < <(nix-locate --regex '^/share/man/man[0-9]*/.*' --top-level   | tr -s ' ')