#!/bin/bash

set -euo pipefail

ds_handle=0
ds_buf=""
declare -A ds_handles
declare -A ds_handle_oids
declare -A ds_object_map
declare -A ds_retraction_handlers

ds_project() {
    # cargo install preserves-tools
    local input="$1"
    local selector="$2"
    shift 2
    echo "$input" | preserves-tool convert --indent=no --select "$selector" "$@"
}

ds_connect_stdio() {
    eval "$1"
    exec 5<&0 6>&1
    ds_flush
    ds_mainloop
}

ds_connect() {
    local addr=$1
    case $(ds_project "$addr" ".^") in
        tcp) nc_args="$(ds_project "$addr" ". 0" --output-format=unquoted) $(ds_project "$addr" ". 1")";;
        unix) nc_args="-U $(ds_project "$addr" ". 0" --output-format=unquoted)";;
        stdio) ds_connect_stdio "$2"; return;;
        *) echo "ds_connect: address '$addr' not supported"; return 1;;
    esac

    local f=$(mktemp -u /tmp/ds.XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX)
    mkfifo $f

    trap "rm -f $f" 2 EXIT RETURN
    {
        eval "$2"
        ds_flush
        ds_mainloop
    } 5< <(nc $nc_args <$f) 6>$f
}

ds_send() {
    echo "$@" >&6
    # echo "SENDING: $@"
}

ds_mainloop() {
    while read ds_packet
    do
        # echo "RECEIVING: $ds_packet"
        while read ds_turnevent
        do
            ds_dispatch "$(ds_project "$ds_turnevent" '. 0')" "$(ds_project "$ds_turnevent" '. 1')"
        done < <(ds_project "$ds_packet" 'seq /')
        ds_flush
    done <&5
}

ds_dispatch() {
    ds_event="$2"
    eval "${ds_object_map[$1]}"
}

ds_action() {
    case $(ds_project "$1" '.embedded . 0') in
        0) ds_dispatch "$(ds_project "$1" '.embedded . 1')" "$2" ;;
        1) ds_buf="${ds_buf}[$(ds_project "$1" '.embedded . 1') $2]" ;;
    esac
}

ds_flush() {
    if [ -n "$ds_buf" ]
    then
        ds_send "[$ds_buf]"
        ds_buf=""
    fi
}

ds_assert() {
    local h="$ds_handle"
    ds_handle=$(($ds_handle + 1))
    ds_action "$1" "<assert $2 $h>"
    if [ -n "${3:-}" ]
    then
        ds_handle_oids[$3]="$1"
        ds_handles[$3]="$h"
    fi
}

ds_retract() {
    ds_action "${ds_handle_oids[$1]}" "<retract ${ds_handles[$1]}>"
}

ds_message() {
    ds_action "$1" "<message $2>"
}

ds_object() {
    local oid="$ds_handle"
    ds_handle=$(($ds_handle + 1))
    ds_object_map[$oid]="$2"
    printf -v $1 '%s' "#![0,$oid]"
}

demo() {
    demo_ds_resolved() {
        local oid="$(ds_project "$ds_event" '^ assert . 0 .embedded . 1')"
        if [ -n "$oid" ]
        then
            ds_ref="#![1 $oid]"
            echo "Dataspace: $ds_ref"

            username="user$$"

            declare -A demo_user_presence
            demo_presence() {
                case $(ds_project "$ds_event" .^) in
                    assert)
                        local h="$(ds_project "$ds_event" '. 1')"
                        local who="$(ds_project "$ds_event" '. 0 . 0')"
                        demo_user_presence[$h]="$who"
                        echo "JOIN: $who"
                        ;;
                    retract)
                        local h="$(ds_project "$ds_event" '. 0')"
                        local who="${demo_user_presence[$h]}"
                        echo "PART: $who"
                        unset 'demo_user_presence[$h]'
                        ;;
                esac
            }
            ds_object presence demo_presence
            ds_assert "$ds_ref" "<Observe <compound <rec Present 1> {0: <bind <_>>}> $presence>"
            ds_assert "$ds_ref" "<Present \"$username\">"

            demo_utterance() {
                ds_project "$ds_event" '^ message . 0'
            }
            ds_object utterance demo_utterance
            ds_assert "$ds_ref" "<Observe <compound <rec Says 2> {0: <bind <_>> 1: <bind <_>>}> $utterance>"

            ds_flush
            ds_mainloop </dev/null &
            mainloop_pid=$!
            while read line
            do
                ds_message "$ds_ref" "<Says \"$username\" \"$line\">"
                ds_flush
            done </dev/tty
            kill $mainloop_pid
            exit 0
        fi
    }
    ds_object bootk demo_ds_resolved
    ds_connect \
        '<unix "./sock">' \
        'ds_assert "#![1 0]" "<resolve <ref \"syndicate\" [] #x\"a6480df5306611ddd0d3882b546e1977\"> $bootk>"'
}

demo