#!/usr/bin/env bash

source $(dirname $0)/reader.sh
source $(dirname $0)/printer.sh

# read
proc READ {
    test ${1} && setvar r = "${1}" || READLINE
    READ_STR ${r}
}

# eval
proc EVAL_AST {
    local ast="${1}" env="${2}"
    #_pr_str "${ast}"; echo "EVAL_AST '${ast}:${r} / ${env}'"
    _obj_type ${ast}; local ot="${r}"
    case{
    symbol {
        local val="${ANON["${ast}"]}"
        eval r="\${${env}["${val}"]}"
        test ${r} || _error "'${val}' not found" }
    list {
        _map_with_type _list EVAL ${ast} ${env} }
    vector {
        _map_with_type _vector EVAL ${ast} ${env} }
    hash_map {
        local res="" key= val="" hm="${ANON["${ast}"]}"
        _hash_map; local new_hm="${r}"
        eval local keys="\${!${hm}[@]}"
        for key in ${keys} {
            eval val="\${${hm}[\"${key}\"]}"
            EVAL ${val} ${env}
            _assoc! ${new_hm} ${key} ${r}
        }
        setvar r = "${new_hm}" }
    * {
        setvar r = "${ast}" }
    }
}

proc EVAL {
    local ast="${1}" env="${2}"
    setvar r = ''
    [[ "${__ERROR}" ]] && return 1
    #_pr_str "${ast}"; echo "EVAL '${r} / ${env}'"
    _obj_type ${ast}; local ot="${r}"
    if [[ "${ot}" != "list" ]] {
        EVAL_AST ${ast} ${env}
        return
    }
    _empty? ${ast} && setvar r = "${ast}" && return

    # apply list
    EVAL_AST ${ast} ${env}
    [[ "${__ERROR}" ]] && return 1
    local el="${r}"
    _first ${el}; local f="${r}"
    _rest ${el}; local args="${ANON["${r}"]}"
    #echo "invoke: ${f} ${args}"
    eval ${f} ${args}
}

# print
proc PRINT {
    if [[ "${__ERROR}" ]] {
        _pr_str ${__ERROR} yes
        setvar r = ""Error: ${r}""
        setvar __ERROR = ''
    } else {
        _pr_str ${1} yes
    }
}

# repl
declare -A REPL_ENV
proc REP {
    setvar r = ''
    READ ${1}
    EVAL ${r} REPL_ENV
    PRINT ${r}
}

proc plus { setvar r = $(( ${ANON["${1}"]} + ${ANON["${2}"]} )); _number ${r}; }
proc minus { setvar r = $(( ${ANON["${1}"]} - ${ANON["${2}"]} )); _number ${r}; }
proc multiply { setvar r = $(( ${ANON["${1}"]} * ${ANON["${2}"]} )); _number ${r}; }
proc divide { setvar r = $(( ${ANON["${1}"]} / ${ANON["${2}"]} )); _number ${r}; }

setvar REPL_ENV["+"]=plus
setvar REPL_ENV["-"]=minus
setvar REPL_ENV["__STAR__"]=multiply
setvar REPL_ENV["/"]=divide

# repl loop
while true {
    READLINE "user> " || exit "$?"
    [[ "${r}" ]] && REP ${r} && echo ${r}
}