import mem:*
import io:*
import str:*
import vec:*
import vec_literals:*
import util:*
import map:*
import rc:*

import fungll:*

adt KPValue_int {
    True,                                   //       101 1 0
    False,                                  //       100 1 0
    Env: *KPEnv,                             //       011 1 0
    Combiner: KPCombiner,                   //       010 1 0
    BuiltinCombiner: KPBuiltinCombiner,     //       ''' ' '
    String: str,                            //       001 1 0
    Symbol: str,                            //       000 1 0
    Int: int,                               //           0 0

    Vector: rc<vec<KPValue>>,               //<10sizebits> 1
    // same encoding, but encodes 0-length null ptr
    Nil                                     // 00000000000 1
}
obj KPEnv (Object) {
    var data: map<str, KPValue>
    var outer: *KPEnv
    fun construct(): *KPEnv {
        return construct(null<KPEnv>())
    }
    fun construct(outer: *KPEnv): *KPEnv {
        data.construct()
        this->outer = outer
        return this
    }
    fun copy_construct(old: *KPEnv): void {
        data.copy_construct(&old->data)
        outer = old->outer
    }
    fun destruct(): void {
        data.destruct()
        outer = null<KPEnv>()
    }
    fun operator=(other:ref KPEnv):void {
        destruct()
        copy_construct(&other)
    }
    fun set(key: str, val: KPValue) {
        data.set(key, val)
    }
    fun remove(key: str) {
        data.remove(key)
    }
    fun find(key: str): *KPEnv {
        if (data.contains_key(key)) {
            return this
        } else if (outer != null<KPEnv>()) {
            return outer->find(key)
        } else {
            return null<KPEnv>()
        }
    }
    fun get(key: str): KPResult {
        var env = find(key)
        if (env != null<KPEnv>()) {
            return KPResult::Ok(env->data.get(key))
        } else {
            return KPResult::Err(kpString(str("'") + key + "' not found"))
        }
    }
    fun to_string(): str {
        var to_ret = str()
        to_string(str("\t"), to_ret)
        return to_ret
    }
    fun to_string(tabs: ref str, s: ref str) {
        for (var i = 0; i < data.keys.size; i++;) {
            /*s += tabs + data.keys[i] + ": " + data.values[i] + "\n"*/
            s += tabs + data.keys[i] + "\n"
        }
        if outer != null<KPEnv>() {
            outer->to_string(tabs + "\t", s)
        }
    }
}
obj KPBuiltinCombiner (Object) {
    var name: str
    var fp: fun(vec<KPValue>, *KPEnv): KPResult
    fun construct(name: ref str, fp: fun(vec<KPValue>, *KPEnv): KPResult): *KPBuiltinCombiner {
        this->name.copy_construct(&name)
        this->fp = fp
        return this
    }
    fun copy_construct(old: *KPBuiltinCombiner): void {
        this->fp = old->fp
        this->name.copy_construct(&old->name)
    }
    fun destruct(): void {
        this->name.destruct()
    }
    fun operator=(other:ref KPBuiltinCombiner):void {
        destruct()
        copy_construct(&other)
    }
    fun operator==(other: ref KPBuiltinCombiner):bool {
        return false
    }
    fun call(params: vec<KPValue>, dynamic_env: KPValue): KPResult {
        if !dynamic_env.is_env() {
            return KPResult::Err(kpString(pr_str(dynamic_env, true) + " is not an env"))
        }
        return fp(params, dynamic_env.get_env())
    }
}
fun make_builtin_combiner(name: str, f: fun(vec<KPValue>, *KPEnv): KPResult): KPValue {
    var to_ret.construct(name, f): KPBuiltinCombiner
    return nmMV(KPValue_int::BuiltinCombiner(to_ret))
}
obj KPCombiner (Object) {
    var env: *KPEnv
    var dynamic_env_name: str
    var parameters: vec<str>
    var is_variadic: bool
    var body: *KPValue
    fun construct(env: *KPEnv, dynamic_env_name: str, parameters: vec<str>, is_variadic: bool, body: KPValue): *KPCombiner {
        this->env = env
        this->dynamic_env_name.copy_construct(&dynamic_env_name)
        this->parameters.copy_construct(&parameters)
        this->is_variadic = is_variadic
        this->body = new<KPValue>()
        this->body->copy_construct(&body)
        return this
    }
    fun copy_construct(old: *KPCombiner): void {
        this->env = old->env
        this->dynamic_env_name.copy_construct(&old->dynamic_env_name)
        this->parameters.copy_construct(&old->parameters)
        this->is_variadic = old->is_variadic
        this->body = new<KPValue>()
        this->body->copy_construct(old->body)
    }
    fun destruct(): void {
        this->env = null<KPEnv>()
        dynamic_env_name.destruct()
        parameters.destruct()
        delete(body)
        body = null<KPValue>()
    }
    fun operator=(other:ref KPCombiner):void {
        destruct()
        copy_construct(&other)
    }
    fun operator==(other: ref KPCombiner):bool {
        // not sure about env
        return env == other.env && dynamic_env_name == other.dynamic_env_name && parameters == other.parameters && is_variadic == other.is_variadic && body->equals(*other.body)
    }
    // no call b/c need to do in EVAL for TCO
    fun prep_call(params: ref vec<KPValue>, dynamic_env: KPValue): pair<*KPEnv, KPResult> {
        // tco
        if (!is_variadic && parameters.size != params.size) || (is_variadic && parameters.size > params.size + 1) {
            return make_pair(null<KPEnv>(), KPResult::Err(kpString(str("combiner called with the wrong number of parameters: ") + params.size + " but expecting " + parameters.size + ": [ " + str(",").join(parameters) + "], was: " + pr_str(kpVector(params), true) + ", function body is " + pr_str(*body, true))))
        }
        var new_env = new<KPEnv>()->construct(env)
        for (var i = 0; i < parameters.size; i++;) {
            if is_variadic && i == parameters.size - 1 {
                new_env->set(parameters[i], kpVector(params.slice(i, -1)))
            } else {
                new_env->set(parameters[i], params[i])
            }
        }
        new_env->set(dynamic_env_name, dynamic_env)
        return make_pair(new_env, KPResult::Ok(*body))
    }
}

obj KPValue (Object) {
    var internal: KPValue_int
    var meta: *KPValue

    fun construct(): *KPValue {
        internal.copy_construct(&KPValue_int::Nil());
        meta = null<KPValue>()
    }
    fun construct(i: ref KPValue_int, m: *KPValue): *KPValue {
        internal.copy_construct(&i);
        meta = m
    }
    fun copy_construct(other: *KPValue): void {
        internal.copy_construct(&other->internal);
        /*meta = other->meta*/
        if other->meta != null<KPValue>() {
            meta = new<KPValue>()
            meta->copy_construct(other->meta)
        } else {
            meta = null<KPValue>()
        }
    }
    fun operator=(other: ref KPValue): void {
        destruct()
        copy_construct(&other)
    }
    fun destruct(): void {
        if meta != null<KPValue>()
            delete(meta)
        internal.destruct()
    }
    fun equals(other: ref KPValue): bool {
        match (internal) {
           KPValue_int::Vector(d) { match (other.internal) {
                KPValue_int::Vector(db) {
                    if d.get().size != db.get().size {
                        return false
                    }
                    for (var i = 0; i < d.get().size; i++;) {
                        if !d.get()[i].equals(db.get()[i]) {
                            return false
                        }
                    }
                    return true
               }
           } }
           KPValue_int::String(d)  { match (other.internal) { KPValue_int::String(db) { return d == db; } } }
           KPValue_int::Int(d)     { match (other.internal) { KPValue_int::Int(db) { return d == db; } } }
           KPValue_int::Symbol(d)  { match (other.internal) { KPValue_int::Symbol(db) { return d == db; } } }
           KPValue_int::Combiner(d){ match (other.internal) { KPValue_int::Combiner(db) { return d == db; } } }
           KPValue_int::BuiltinCombiner(d) { match (other.internal) { KPValue_int::BuiltinCombiner(db) { return d == db; } } }
           KPValue_int::Env(e)     { match (other.internal) { KPValue_int::Env(eb) { return e == eb; } } }
           KPValue_int::True()     { match (other.internal) { KPValue_int::True() { return true; } } }
           KPValue_int::False()    { match (other.internal) { KPValue_int::False() { return true; } } }
           KPValue_int::Nil()      { match (other.internal) { KPValue_int::Nil() { return true; } } }
        }
        return false
    }
    fun deep_clone(): KPValue {
        match (internal) {
            KPValue_int::Vector(v) {
                return kpVector(v.get())
            }
            KPValue_int::Env(e) {
                var newenv = new<KPEnv>()
                newenv->copy_construct(e)
                return kpEnv(e)
            }
        }
        return *this
    }
    fun is_combiner(): bool {
        match (internal) {
            KPValue_int::Combiner(f) {
                return true
            }
            KPValue_int::BuiltinCombiner(f) {
                return true
            }
        }
        return false
    }
    fun is_env(): bool {
        match (internal) {
            KPValue_int::Env(e) {
                return true
            }
        }
        return false
    }
    fun get_env(): *KPEnv {
        match (internal) {
            KPValue_int::Env(e) {
                return e
            }
        }
        error("Tried to get env on not an env" + pr_str(*this, true))
    }
    fun is_vector(): bool {
        match (internal) {
            KPValue_int::Vector(v) {
                return true
            }
        }
        return false
    }
    fun get_vector_rc(): rc<vec<KPValue>> {
        match (internal) {
            KPValue_int::Vector(v) {
                return v
            }
        }
        error("Tried to get vec on not a vec" + pr_str(*this, true))
    }
    fun is_symbol(): bool {
        match (internal) {
            KPValue_int::Symbol(s) {
                return true
            }
        }
        return false
    }
    fun is_symbol(text: *char): bool {
        match (internal) {
            KPValue_int::Symbol(s) {
                return s == text
            }
        }
        return false
    }
    fun get_symbol_text(): str {
        match (internal) {
            KPValue_int::Symbol(s) {
                return s
            }
        }
        error("get_symbol_text on not symbol")
    }
    fun is_string(): bool {
        match (internal) {
            KPValue_int::String(s) {
                return true
            }
        }
        return false
    }
    fun get_string(): str {
        match (internal) {
            KPValue_int::String(s) {
                return s
            }
        }
        error("get_string on not a string")
    }
    fun is_int(): bool {
        match (internal) {
            KPValue_int::Int(i) {
                return true
            }
        }
        return false
    }
    fun get_int(): int {
        match (internal) {
            KPValue_int::Int(i) {
                return i
            }
        }
        error("get_int on not an int")
    }
    fun is_nil(): bool {
        match (internal) {
            KPValue_int::Nil() {
                return true
            }
        }
        return false
    }
    fun is_truthy(): bool {
        match (internal) {
            KPValue_int::False() {
                return false
            }
            KPValue_int::Nil() {
                return false
            }
        }
        return true
    }
    fun is_pair(): bool {
        return is_vector() && get_vector_rc().get().size > 0
    }
}


fun nmMV(i: ref KPValue_int): KPValue {
    var to_ret.construct(i, null<KPValue>()): KPValue
    return to_ret
}
fun kpTrue(): KPValue {
    return nmMV(KPValue_int::True())
}
fun kpFalse(): KPValue {
    return nmMV(KPValue_int::False())
}
fun bool_to_KPValue(b: bool): KPValue {
    if b {
        return nmMV(KPValue_int::True())
    } else {
        return nmMV(KPValue_int::False())
    }
}
fun kpString(s: ref str): KPValue {
    return nmMV(KPValue_int::String(s))
}
fun kpSymbol(s: ref str): KPValue {
    return nmMV(KPValue_int::Symbol(s))
}
fun kpInt(i: int): KPValue {
    return nmMV(KPValue_int::Int(i))
}
fun kpVector(v: ref vec<KPValue>): KPValue {
    var rcd.construct(v): rc<vec<KPValue>>
    return nmMV(KPValue_int::Vector(rcd))
}
fun kpNil(): KPValue {
    return nmMV(KPValue_int::Nil())
}
fun kpEnv(e: *KPEnv): KPValue {
    return nmMV(KPValue_int::Env(e))
}

fun read_str(grammar: ref Grammer<KPResult,KPValue>, s: str): pair<int, KPResult> {
    var BSR = fungll(grammar, grammar.start_symbol, s)
    var longest = -1
    for (var i = 0; i < BSR.data.size; i++;) {
        if BSR.data[i].nonterminal == grammar.start_symbol && BSR.data[i].left == 0 && BSR.data[i].idx_into_rule == grammar.nonterminals[(-1*BSR.data[i].nonterminal)-1][BSR.data[i].rule_idx].size {
            longest = BSR.data[i].right
        }
    }
    if longest >= 0 {
        return make_pair(longest, grammar.eval_BSR(s.slice(0, longest), BSR))
    } else {
        println("trying to parse: " + s)
        println(str("length of BSR is: ") + BSR.size())
        for (var i = 0; i < BSR.data.size; i++;) {
            println(str() + i + ": " + grammar.to_string(BSR.data[i]))
        }
        println("Parse failed")
        return make_pair(-1, KPResult::Err(kpString(str("failed to parse"))))
    }
}

adt KPResult {
    Ok: KPValue,
    Err: KPValue
}
fun is_err(r: KPResult): bool {
    match (r) {
        KPResult::Err(e) {
            return true
        }
    }
    return false
}
fun get_err(r: KPResult): KPValue {
    match (r) {
        KPResult::Err(e) {
            return e
        }
    }
    /*return kpSymbol(str("get-err-not-error"))*/
    error("get-err-not-error")
}
fun get_value(r: KPResult): KPValue {
    match (r) {
        KPResult::Ok(v) {
            return v
        }
    }
    /*return kpSymbol(str("get-value-is-error"))*/
    error("get-value-is-error")
}
fun pr_str(v: KPValue, print_readably: bool): str {
    match (v.internal) {
        KPValue_int::Vector(l) {
            var to_ret = str("( ")
            for (var i = 0; i < l.get().size; i++;) {
                if (i != 0) {
                    to_ret += " "
                }
                to_ret += pr_str(l.get()[i], print_readably)
            }
            return to_ret + " )"
        }
        KPValue_int::Int(i) {
            return to_string(i)
        }
        KPValue_int::String(s) {
            if print_readably {
                var to_ret = str("\"") //"
                for (var i = 0; i < s.length(); i++;) {
                    if s[i] == '\n' {
                        to_ret += '\\'
                        to_ret += 'n'
                    } else if s[i] == '\\' || s[i] == '"' {
                        to_ret += '\\'
                        to_ret += s[i]
                    } else {
                        to_ret += s[i]
                    }
                }
                return to_ret + "\"" //"
            } else {
                return s
            }
        }
        KPValue_int::Symbol(s) {
            if print_readably {
                return "'" + s
            } else {
                return s
            }
        }
        KPValue_int::BuiltinCombiner(f) {
            return str("builtin combiner")
        }
        KPValue_int::Combiner(f) {
            return str("combiner")
        }
        KPValue_int::Env(e) {
            return str("environment")
        }
        KPValue_int::True() {
            return str("true")
        }
        KPValue_int::False() {
            return str("false")
        }
        KPValue_int::Nil() {
            return str("nil")
        }
    }
    error("can't print")
}

fun READ(grammar: ref Grammer<KPResult, KPValue>, s: str): KPResult {
    var to_ret = read_str(grammar, s)
    if to_ret.first != s.length() {
        if is_err(to_ret.second) {
            return to_ret.second
        } else {
            println("parsed to var: " + pr_str(get_value(to_ret.second), true))
        }
        error("parsed some, but not all")
    }
    return to_ret.second
}

fun EVAL(env: *KPEnv, ast: KPValue): KPResult {
    // for tco
    while (true) {
        match (ast.internal) {
            KPValue_int::Vector(l) {
                if (l.get().size == 0) {
                    return KPResult::Err(kpString(str("Eval a zero length vector")))
                } else {
                    // this breaks tco?
                    var combiner = EVAL(env, l.get()[0])
                    if is_err(combiner) {
                        return combiner
                    }
                    match (get_value(combiner).internal) {
                        KPValue_int::BuiltinCombiner(f) {
                            return f.call(l.get().slice(1,-1), kpEnv(env))
                        }
                        KPValue_int::Combiner(f) {
                            var call_pair = f.prep_call(l.get().slice(1, -1), kpEnv(env))
                            if is_err(call_pair.second) {
                                return call_pair.second
                            }
                            env = call_pair.first
                            ast = get_value(call_pair.second)
                            continue
                        }
                    }
                    return KPResult::Err(kpString(str("trying to call not a combiner: ") + pr_str(l.get()[0], true)))
                }
            }
            KPValue_int::Symbol(s) {
                return env->get(s)
            }
        }
        // everything else is self-evaluating
        return KPResult::Ok(ast)
    }
}

fun rep(grammar: ref Grammer<KPResult, KPValue>, env: *KPEnv, a: str): str {
    var read = READ(grammar, a)
    if is_err(read) {
        return pr_str(get_err(read), true)
    } else {
        var evaled = EVAL(env, get_value(read))
        if is_err(evaled) {
            return str("Exception: ") + pr_str(get_err(evaled), true)
        } else {
            return pr_str(get_value(evaled), true)
        }
    }
}

fun function_call(f: KPValue, params: ref vec<KPValue>, env: KPValue): KPResult {
    match (f.internal) {
        KPValue_int::BuiltinCombiner(f) {
            return f.call(params, env)
        }
        KPValue_int::Combiner(f) {
            var call_pair = f.prep_call(params, env)
            if is_err(call_pair.second) {
                return call_pair.second
            }
            return EVAL(call_pair.first, get_value(call_pair.second))
        }
    }
    return KPResult::Err(kpString(str("trying to apply not a combiner: ") + pr_str(f ,true)))
}

fun print_wrapper(params: ref vec<KPValue>, sep: *char, print_readably: bool): str {
    var to_ret = str()
    for (var i = 0; i < params.size; i++;) {
        to_ret += pr_str(params[i], print_readably)
        if i != params.size-1 {
            to_ret += sep
        }
    }
    return to_ret
}

fun main(argc: int, argv: **char): int {

    var grammar.construct(): Grammer<KPResult, KPValue>

    var ret_nil_term: fun(ref KPValue, ref str, int, int): KPResult = fun(_: ref KPValue, input: ref str, l: int, r: int): KPResult { return KPResult::Ok(kpNil()); }
    var ret_nil_sym: fun(ref KPValue, ref vec<KPResult>): KPResult = fun(_: ref KPValue, x: ref vec<KPResult>): KPResult { return KPResult::Ok(kpNil()); }
    var ret_0_sym: fun(ref KPValue, ref vec<KPResult>): KPResult = fun(_: ref KPValue, x: ref vec<KPResult>): KPResult { return x[0]; }

    var WS = grammar.add_new_nonterminal("WS", vec(grammar.add_terminal("( |	|
|(;[ -~]*
))+", kpNil(), ret_nil_term)), kpNil(), ret_nil_sym)
    var optional_WS = grammar.add_new_nonterminal("optional_WS", vec<int>(), kpNil(), ret_nil_sym)
    grammar.add_to_nonterminal(optional_WS, vec(WS), kpNil(), ret_nil_sym)

    var atom = grammar.add_new_nonterminal("atom", vec(grammar.add_terminal("-?[0-9]+", kpNil(), fun(_: ref KPValue, input: ref str, l: int, r: int): KPResult { return KPResult::Ok(kpInt(string_to_num<int>(input.slice(l,r)))); })), kpNil(), ret_0_sym)
    grammar.add_to_nonterminal(atom, vec(grammar.add_terminal("\"([#-[]|	|[]-~]|(\\\\)|(\\n)|(\\t)|(\\\*)|(\\0)|
|[ -!]|(\\\\\"))*\"", kpNil(), fun(_: ref KPValue, input: ref str, l: int, r: int): KPResult { //"
        var to_ret = str()
        for (var i = l+1; i < r-1; i++;) {
            if input[i] == '\\' {
                if input[i+1] == 'n' {
                    to_ret += '\n'
                } else if input[i+1] == '\\' || input[i+1] == '"' {
                    to_ret += input[i+1]
                } else {
                    return KPResult::Err(kpString(str("bad string escape")))
                }
                // skip
                i++
            } else {
                to_ret += input[i]
            }
        }
        return KPResult::Ok(kpString(to_ret));
    })), kpNil(), ret_0_sym)
    grammar.add_to_nonterminal(atom, vec(grammar.add_terminal("-|(([a-z]|[A-Z]|_|\\*|/|\\?|\\+|!|=|&|<|>)([a-z]|[A-Z]|_|[0-9]|\\*|\\?|\\+|-|!|=|&|<|>)*)", kpNil(), fun(_: ref KPValue, input: ref str, l: int, r: int): KPResult {
        var s = input.slice(l,r)
        if s == "true" {
            return KPResult::Ok(kpTrue());
        } else if s == "false" {
            return KPResult::Ok(kpFalse());
        } else if s == "nil" {
            return KPResult::Ok(kpNil());
        } else {
            return KPResult::Ok(kpSymbol(input.slice(l,r)));
        }
    })), kpNil(), ret_0_sym)

    var form = grammar.add_new_nonterminal("form", vec(atom), kpNil(), ret_0_sym)
    var space_forms = grammar.add_new_nonterminal("space_forms", vec<int>(), kpNil(), fun(_: ref KPValue, x: ref vec<KPResult>): KPResult {
        return KPResult::Ok(kpVector(vec<KPValue>()))
    })
    grammar.add_to_nonterminal(space_forms, vec(form), kpNil(), fun(_: ref KPValue, x: ref vec<KPResult>): KPResult {
        if is_err(x[0]) {
            return x[0]
        }
        return KPResult::Ok(kpVector(vec(get_value(x[0]))))
    })
    grammar.add_to_nonterminal(space_forms, vec(form, WS, space_forms), kpNil(), fun(_: ref KPValue, x: ref vec<KPResult>): KPResult {
        if is_err(x[0]) {
            return x[0]
        }
        if is_err(x[2]) {
            return x[2]
        }
        return KPResult::Ok(kpVector(vec(get_value(x[0])) + get_value(x[2]).get_vector_rc().get()))
    })

    grammar.add_to_nonterminal(form, vec(grammar.add_terminal("\\(", kpNil(), ret_nil_term),
                                                       optional_WS,
                                                       grammar.add_terminal("\\)", kpNil(), ret_nil_term)), kpNil(), fun(_: ref KPValue, x: ref vec<KPResult>): KPResult { return KPResult::Ok(kpVector(vec<KPValue>())); })
    grammar.add_to_nonterminal(form, vec(grammar.add_terminal("\\(", kpNil(), ret_nil_term),
                                                       optional_WS,
                                                       space_forms,
                                                       optional_WS,
                                                       grammar.add_terminal("\\)", kpNil(), ret_nil_term)), kpNil(), fun(_: ref KPValue, x: ref vec<KPResult>): KPResult { return x[2]; })

    grammar.set_start_symbol(form)


    var env = new<KPEnv>()->construct()

    env->set(str("+"), make_builtin_combiner(str("+"), fun(params: vec<KPValue>, dynamic_env: *KPEnv): KPResult {
        var to_ret = 0
        for (var i = 0; i < params.size; i++;) {
            var ip = EVAL(dynamic_env, params[i])
            if is_err(ip) {
                return ip
            }
            match (get_value(ip).internal) {
                KPValue_int::Int(v) {
                    to_ret += v
                    continue
                }
            }
            return KPResult::Err(kpString(str("called + with not an int: ") + pr_str(params[i], false)))
        }
        return KPResult::Ok(kpInt(to_ret))
    }));

    if argc == 3 && str(argv[1]) == "-C" {
        error("-C not implemented")
        //env->set(str("*ARGV*"), kpNil())
        //var evaled = ERS(vec(kpString(str(argv[2]))))
        //if is_err(evaled) {
        //    printlnerr(str("Exception: ") + pr_str(get_err(evaled), true))
        //} else {
        //    println("Result: " + pr_str(get_value(evaled), true))
        //}
    } else if argc >= 2 {
        var params = vec<KPValue>()
        for (var i = 2; i < argc; i++;) {
            params.add(kpString(str(argv[i])))
        }
        env->set(str("*ARGV*"), kpVector(params))
        var eval_result_str = rep(grammar, env, str("(load-file \"") + argv[1] + "\")")
        println(eval_result_str)
        if eval_result_str.length() >= 11 && eval_result_str.slice(0,11) == "Exception: " {
            error("aborting compile")
        }
        // check for compile
        var main = env->get(str("main"))
        if !is_err(main) {
            println("Starting compile!")
            error("Compiler not implemented")
        } else {
            println("No main function to compile, exiting")
        }
    } else {
        while (true) {
            var line = get_line(str("user> "), 1024)
            if (line == "***EOF***")
                break
            println(rep(grammar, env, line))
        }
    }
}