#!/bin/bash


usage() {
    local self="${0##*/}"
    local err=$1; shift
    echo >&2 "usage: $self DIR [DIR...]"
    echo >&2 ""
    echo >&2 "$err"
    exit 3
}

warn() {
    echo >&2 "$@"
}

die() {
    echo >&2 "$@"
    exit 3
}

list_files() {
    local dir
    for dir in "${Dirs[@]}"; do
        echo "$dir/root.log"
        seq -f "$dir/task-rep%02.0f.log" 0 3
        seq -f "$dir/task-cmd%02.0f.log" 0 9
    done
}

open_files() {
    local i=0
    local path=0
    for path in "$@"; do
        twinner -t "$path" -O "$Tmp/pid-$i" -P -c "tail -F \"$path\"" &
        sleep 0.1   # allow WM to have predictable order of windows
        ((i++))
    done
}

onclose() {
    warn ""
    warn "got SIGINT; killing: Pids=(${Pids[*]})"
    kill "${Pids[@]}"
    rm -r "$Tmp"
}

main() {
    test "$#" -eq 0 && usage "no DIRs?"
    local Dirs=("$@")
    local filelist=()
    local Pids=()
    local Tmp

    Tmp=$(mktemp -d /tmp/watch_logs.XXXXXXXX)

    list_files >"$Tmp/files"
    mapfile -t filelist <"$Tmp/files"

    open_files "${filelist[@]}"
    sleep 2
    cat "$Tmp/pid-"* > "$Tmp/pids"
    mapfile -t Pids <"$Tmp/pids"

    warn "spawned children: ${Pids[*]}"
    warn "press ^C to close all open files"
    wait # "${Pids[@]}"

    rm -r "$Tmp"
}

trap onclose SIGINT

main "$@"