#!/bin/bash
function main () {
local -
set +e +m -f
declare -- NORM=""
declare -- RED=""
declare -- GREEN=""
declare -- YELLOW=""
declare -- CYAN=""
declare -- IRED=""
declare -- IGREEN=""
declare -- IBLUE=""
declare -- ICYAN=""
declare -- IMAGENTA=""
declare -- WHITE=""
declare -- quiet="0"
declare -- debug="0"
declare -i cpus="3"
declare -A tasks=([ls]="ls -oF" [del]="rm -rf wfc; echo del wfc recursive" [run]="cd wfc; cargo build --release; cargo run --release & sleep 6 ; kill %1" [mv]="mv -v wavefunctioncollapse-main wfc" [wget]="wget https://github.com/brianfeaster/wavefunctioncollapse/archive/refs/heads/main.zip" [rm]="rm -v main.zip; echo deleted main.zip" [zip]="unzip -o main.zip" )
declare -A taskStates=([ls]="ready" [del]="ready" [run]="ready" [mv]="ready" [wget]="ready" [rm]="ready" [zip]="ready" )
declare -a dependencytree=([0]="* 1 " [1]="+ wget zip mv ls 2 del " [2]="* rm run ")
scheduler
}
scheduler () 
{ 
    local pid2task=() errnum=0;
    while ((${#pid2task[*]} < cpus)) && spawnNextFree 0; do
        :;
    done;
    while waitForATask; do
        while ((${#pid2task[*]} < cpus)) && spawnNextFree 0; do
            :;
        done;
    done;
    ((debug)) && prettyPrintEverything;
    return $errnum
}
spawnNextFree () 
{ 
    if [ "${1//[0-9]}" == "" ]; then
        local depth=$1 taskId allFinished=1;
        case ${dependencytree[depth]%% *} in 
            "*")
                for taskId in ${dependencytree[depth]#* };
                do
                    spawnNextFree $taskId;
                    case $? in 
                        0)
                            return 0
                        ;;
                        2)

                        ;;
                        *)
                            allFinished=0
                        ;;
                    esac;
                done;
                return $((allFinished ? 2 : 1))
            ;;
            "+")
                for taskId in ${dependencytree[depth]#* };
                do
                    spawnNextFree $taskId;
                    case $? in 
                        2)

                        ;;
                        *)
                            return $?
                        ;;
                    esac;
                done;
                return 2
            ;;
            *)
                printf "$IRED[EXCEPTION unknown dependency op '$p'] $NORM";
                prettyPrintGraph;
                exit 4
            ;;
        esac;
    else
        local taskId=$1;
        case ${taskStates[$taskId]} in 
            ready)
                spawnTask;
                return 0
            ;;
            running)
                return 1
            ;;
            finished)
                return 2
            ;;
            failed | *)
                return 3
            ;;
        esac;
    fi
}
spawnTask () 
{ 
    local taskCmd="${tasks[$taskId]}";
    if ((quiet)); then
        eval "$taskCmd" &
    else
        eval "{ $taskCmd ; }         2> >(while read -r l; do echo   \"$RED[$BASHPID:$taskId]$NORM \$l\"; done)         1> >(while read -r l; do echo \"$GREEN[$BASHPID:$taskId]$NORM \$l\"; done)" &
    fi;
    pid2task[$!]=$taskId;
    taskStates[$taskId]=running;
    ((debug)) && echo "$IMAGENTA[Spawned $!:$taskId]$NORM $taskCmd";
    return 0
}
waitForATask () 
{ 
    local pid taskId taskCmd;
    ((${#pid2task[@]})) || return 255;
    ((debug)) && echo $(
        echo -n "$IMAGENTA[Waiting on ${#pid2task[@]} tasks]$NORM ${!pid2task[@]} "
        ((2 <= debug)) && prettyPrintGraph
    );
    wait -p pid -n ${!pid2task[@]};
    errnum=$?;
    taskId=${pid2task[$pid]};
    taskCmd=${tasks[$taskId]};
    unset pid2task[$pid];
    if ((errnum)); then
        taskStates[$taskId]=failed;
        reportTaskFail;
        return $errnum;
    else
        taskStates[$taskId]=finished;
        ((debug)) && reportTaskCompleted;
        return 0;
    fi
}
prettyPrintEverything () 
{ 
    echo -e "${WHITE}--TASKS--------$NORM";
    for k in $(sort <(tr \  \\n <<<${!tasks[@]}));
    do
        echo " $GREEN$k $YELLOW${taskStates[$k]} $NORM${tasks[$k]}";
    done;
    echo -ne "${WHITE}TREE$NORM\n ";
    prettyPrintGraph
}
prettyPrintGraph () 
{ 
    local buff=$(_prettyPrintGraph 0);
    echo $buff
}
_prettyPrintGraph () 
{ 
    if [ "${1//[0-9]}" == "" ]; then
        local a w="(";
        for a in ${dependencytree[$1]};
        do
            printf "$w";
            _prettyPrintGraph $a;
            w=" ";
        done;
        printf ")";
    else
        case ${taskStates[$1]} in 
            ready)
                printf "$1"
            ;;
            running)
                printf "$IGREEN$1$NORM"
            ;;
            finished)
                printf "$IBLUE$1$NORM"
            ;;
            failed)
                printf "$IRED$1$NORM"
            ;;
            *)
                printf "$1"
            ;;
        esac;
    fi
}
reportTaskFail () 
{ 
    echo "$IRED[Exception pid $pid:$taskId returned $errnum]$NORM $taskCmd"
}
reportTaskCompleted () 
{ 
    echo $(
      echo -n "$IGREEN[Completed $pid:$taskId]$NORM $taskCmd "
      ((2 <= debug)) && prettyPrintGraph
    )
}
main