#include "cubescript.hh"
#include "cs_vm.hh"
#include "cs_util.hh"

namespace cscript {

ostd::String intstr(CsInt v) {
    char buf[256];
    snprintf(buf, sizeof(buf), IntFormat, v);
    return buf;
}

ostd::String floatstr(CsFloat v) {
    char buf[256];
    snprintf(buf, sizeof(buf), v == CsInt(v) ? RoundFloatFormat : FloatFormat, v);
    return buf;
}

char *cs_dup_ostr(ostd::ConstCharRange s) {
    char *r = new char[s.size() + 1];
    memcpy(r, s.data(), s.size());
    r[s.size()] = 0;
    return r;
}

bool cs_check_num(ostd::ConstCharRange s) {
    if (isdigit(s[0])) {
        return true;
    }
    switch (s[0]) {
        case '+':
        case '-':
            return isdigit(s[1]) || ((s[1] == '.') && isdigit(s[2]));
        case '.':
            return isdigit(s[1]) != 0;
        default:
            return false;
    }
}

Ident::Ident(): type(ID_UNKNOWN) {}

/* ID_IVAR */
Ivar::Ivar(
    ostd::ConstCharRange n, CsInt m, CsInt x, CsInt *s, VarCb f, int flagsv
) {
    type = ID_IVAR;
    flags = flagsv | (m > x ? IDF_READONLY : 0);
    name = n;
    minval = m;
    maxval = x;
    cb_var = ostd::move(f);
    storage.ip = s;
}

/* ID_FVAR */
Fvar::Fvar(
    ostd::ConstCharRange n, CsFloat m, CsFloat x, CsFloat *s,
    VarCb f, int flagsv
) {
    type = ID_FVAR;
    flags = flagsv | (m > x ? IDF_READONLY : 0);
    name = n;
    minvalf = m;
    maxvalf = x;
    cb_var = ostd::move(f);
    storage.fp = s;
}

/* ID_SVAR */
Svar::Svar(ostd::ConstCharRange n, char **s, VarCb f, int flagsv) {
    type = ID_SVAR;
    flags = flagsv;
    name = n;
    cb_var = ostd::move(f);
    storage.sp = s;
}

/* ID_ALIAS */
Alias::Alias(ostd::ConstCharRange n, char *a, int flagsv) {
    type = ID_ALIAS;
    valtype = VAL_STR;
    flags = flagsv;
    name = n;
    code = nullptr;
    stack = nullptr;
    val.s = a;
    val.len = strlen(a);
}
Alias::Alias(ostd::ConstCharRange n, CsInt a, int flagsv) {
    type = ID_ALIAS;
    valtype = VAL_INT;
    flags = flagsv;
    name = n;
    code = nullptr;
    stack = nullptr;
    val.i = a;
}
Alias::Alias(ostd::ConstCharRange n, CsFloat a, int flagsv) {
    type = ID_ALIAS;
    valtype = VAL_FLOAT;
    flags = flagsv;
    name = n;
    code = nullptr;
    stack = nullptr;
    val.f = a;
}
Alias::Alias(ostd::ConstCharRange n, int flagsv) {
    type = ID_ALIAS;
    valtype = VAL_NULL;
    flags = flagsv;
    name = n;
    code = nullptr;
    stack = nullptr;
}
Alias::Alias(ostd::ConstCharRange n, TaggedValue const &v, int flagsv) {
    type = ID_ALIAS;
    valtype = v.p_type;
    flags = flagsv;
    name = n;
    code = nullptr;
    stack = nullptr;
    val = v;
}

/* ID_COMMAND */
Command::Command(
    int t, ostd::ConstCharRange n, ostd::ConstCharRange args,
    ostd::Uint32 amask, int nargs, CmdFunc f
):
    cargs(!args.empty() ? cs_dup_ostr(args) : nullptr),
    argmask(amask), numargs(nargs), cb_cftv(ostd::move(f))
{
    type = t;
    flags = 0;
    name = n;
}

void cs_init_lib_base(CsState &cs);

CsState::CsState() {
    noalias.id = nullptr;
    noalias.next = nullptr;
    noalias.usedargs = (1 << MaxArguments) - 1;
    noalias.argstack = nullptr;
    for (int i = 0; i < MaxArguments; ++i) {
        char buf[32];
        snprintf(buf, sizeof(buf), "arg%d", i + 1);
        new_ident(static_cast<char const *>(buf), IDF_ARG);
    }
    dummy = new_ident("//dummy");
    add_ident(new Ivar("numargs", MaxArguments, 0, &numargs));
    add_ident(new Ivar("dbgalias", 0, 1000, &dbgalias));
    cs_init_lib_base(*this);
}

CsState::~CsState() {
    for (auto &p: idents.iter()) {
        Ident *i = p.second;
        if (i->type == ID_ALIAS) {
            static_cast<Alias *>(i)->force_null();
            delete[] reinterpret_cast<ostd::Uint32 *>(i->code);
        } else if (i->type == ID_COMMAND || i->type >= ID_LOCAL) {
            delete[] static_cast<Command *>(i)->cargs;
        }
        delete i;
    }
}

void CsState::clear_override(Ident &id) {
    if (!(id.flags & IDF_OVERRIDDEN)) {
        return;
    }
    switch (id.type) {
        case ID_ALIAS:
            if (id.get_valtype() == VAL_STR) {
                delete[] id.val.s;
            }
            id.clean_code();
            id.valtype = VAL_STR;
            id.val.s = cs_dup_ostr("");
            id.val.len = 0;
            break;
        case ID_IVAR:
            *id.storage.ip = id.overrideval.i;
            id.changed();
            break;
        case ID_FVAR:
            *id.storage.fp = id.overrideval.f;
            id.changed();
            break;
        case ID_SVAR:
            delete[] *id.storage.sp;
            *id.storage.sp = id.overrideval.s;
            id.changed();
            break;
    }
    id.flags &= ~IDF_OVERRIDDEN;
}

void CsState::clear_overrides() {
    for (auto &p: idents.iter()) {
        clear_override(*(p.second));
    }
}

Ident *CsState::new_ident(ostd::ConstCharRange name, int flags) {
    Ident *id = get_ident(name);
    if (!id) {
        if (cs_check_num(name)) {
            cs_debug_code(
                *this, "number %s is not a valid identifier name", name
            );
            return dummy;
        }
        id = add_ident(new Alias(name, flags));
    }
    return id;
}

Ident *CsState::force_ident(TaggedValue &v) {
    switch (v.get_type()) {
        case VAL_IDENT:
            return v.id;
        case VAL_MACRO:
        case VAL_CSTR: {
            Ident *id = new_ident(v.s);
            v.set_ident(id);
            return id;
        }
        case VAL_STR: {
            Ident *id = new_ident(v.s);
            delete[] v.s;
            v.set_ident(id);
            return id;
        }
    }
    v.cleanup();
    v.set_ident(dummy);
    return dummy;
}

bool CsState::reset_var(ostd::ConstCharRange name) {
    Ident *id = get_ident(name);
    if (!id) {
        return false;
    }
    if (id->flags & IDF_READONLY) {
        cs_debug_code(*this, "variable %s is read only", id->name);
        return false;
    }
    clear_override(*id);
    return true;
}

void CsState::touch_var(ostd::ConstCharRange name) {
    Ident *id = get_ident(name);
    if (id && id->is_var()) {
        id->changed();
    }
}

void CsState::set_alias(ostd::ConstCharRange name, TaggedValue &v) {
    Ident *id = get_ident(name);
    if (id) {
        switch (id->type) {
            case ID_ALIAS:
                if (id->index < MaxArguments) {
                    id->set_arg(*this, v);
                } else {
                    id->set_alias(*this, v);
                }
                return;
            case ID_IVAR:
                set_var_int_checked(id, v.get_int());
                break;
            case ID_FVAR:
                set_var_float_checked(id, v.get_float());
                break;
            case ID_SVAR:
                set_var_str_checked(id, v.get_str());
                break;
            default:
                cs_debug_code(
                    *this, "cannot redefine builtin %s with an alias", id->name
                );
                break;
        }
        v.cleanup();
    } else if (cs_check_num(name)) {
        cs_debug_code(*this, "cannot alias number %s", name);
        v.cleanup();
    } else {
        add_ident(new Alias(name, v, identflags));
    }
}

void CsState::print_var_int(Ident *id, CsInt i) {
    if (i < 0) {
        writefln("%s = %d", id->name, i);
        return;
    }
    if (id->flags & IDF_HEX) {
        if (id->maxval == 0xFFFFFF) {
            writefln(
                "%s = 0x%.6X (%d, %d, %d)", id->name,
                i, (i >> 16) & 0xFF, (i >> 8) & 0xFF, i & 0xFF
            );
        } else {
            writefln("%s = 0x%X", id->name, i);
        }
    } else {
        writefln("%s = %d", id->name, i);
    }
}

void CsState::print_var_float(Ident *id, CsFloat f) {
    writefln("%s = %s", id->name, floatstr(f));
}

void CsState::print_var_str(Ident *id, ostd::ConstCharRange s) {
    if (ostd::find(s, '"').empty()) {
        writefln("%s = \"%s\"", id->name, s);
    } else {
        writefln("%s = [%s]", id->name, s);
    }
}

void CsState::print_var(Ident *id) {
    switch (id->type) {
        case ID_IVAR:
            print_var_int(id, *id->storage.ip);
            break;
        case ID_FVAR:
            print_var_float(id, *id->storage.fp);
            break;
        case ID_SVAR:
            print_var_str(id, *id->storage.sp);
            break;
    }
}

void TaggedValue::cleanup() {
    switch (get_type()) {
        case VAL_STR:
            delete[] s;
            break;
        case VAL_CODE:
            ostd::Uint32 *bcode = const_cast<ostd::Uint32 *>(
                reinterpret_cast<ostd::Uint32 const *>(code)
            );
            if (bcode[-1] == CODE_START) {
                delete[] bcode;
            }
            break;
    }
}

void TaggedValue::force_null() {
    if (get_type() == VAL_NULL) {
        return;
    }
    cleanup();
    set_null();
}

CsFloat TaggedValue::force_float() {
    CsFloat rf = 0.0f;
    switch (get_type()) {
        case VAL_INT:
            rf = i;
            break;
        case VAL_STR:
        case VAL_MACRO:
        case VAL_CSTR:
            rf = cs_parse_float(s);
            break;
        case VAL_FLOAT:
            return f;
    }
    cleanup();
    set_float(rf);
    return rf;
}

CsInt TaggedValue::force_int() {
    CsInt ri = 0;
    switch (get_type()) {
        case VAL_FLOAT:
            ri = f;
            break;
        case VAL_STR:
        case VAL_MACRO:
        case VAL_CSTR:
            ri = cs_parse_int(s);
            break;
        case VAL_INT:
            return i;
    }
    cleanup();
    set_int(ri);
    return ri;
}

ostd::ConstCharRange TaggedValue::force_str() {
    ostd::String rs;
    switch (get_type()) {
        case VAL_FLOAT:
            rs = ostd::move(floatstr(f));
            break;
        case VAL_INT:
            rs = ostd::move(intstr(i));
            break;
        case VAL_MACRO:
        case VAL_CSTR:
            rs = ostd::ConstCharRange(s, len);
            break;
        case VAL_STR:
            return s;
    }
    cleanup();
    set_str(ostd::move(rs));
    return s;
}

static inline CsInt cs_get_int(IdentValue const &v, int type) {
    switch (type) {
        case VAL_FLOAT:
            return CsInt(v.f);
        case VAL_INT:
            return v.i;
        case VAL_STR:
        case VAL_MACRO:
        case VAL_CSTR:
            return cs_parse_int(v.s);
    }
    return 0;
}

CsInt TaggedValue::get_int() const {
    return cs_get_int(*this, get_type());
}

CsInt Ident::get_int() const {
    return cs_get_int(val, get_valtype());
}

static inline CsFloat cs_get_float(IdentValue const &v, int type) {
    switch (type) {
        case VAL_FLOAT:
            return v.f;
        case VAL_INT:
            return CsFloat(v.i);
        case VAL_STR:
        case VAL_MACRO:
        case VAL_CSTR:
            return cs_parse_float(v.s);
    }
    return 0.0f;
}

CsFloat TaggedValue::get_float() const {
    return cs_get_float(*this, get_type());
}

CsFloat Ident::get_float() const {
    return cs_get_float(val, get_valtype());
}

Bytecode *TaggedValue::get_code() const {
    if (get_type() != VAL_CODE) {
        return nullptr;
    }
    return const_cast<Bytecode *>(code);
}

Ident *TaggedValue::get_ident() const {
    if (get_type() != VAL_IDENT) {
        return nullptr;
    }
    return id;
}

static inline ostd::String cs_get_str(IdentValue const &v, int type) {
    switch (type) {
    case VAL_STR:
    case VAL_MACRO:
    case VAL_CSTR:
        return ostd::ConstCharRange(v.s, v.len);
    case VAL_INT:
        return intstr(v.i);
    case VAL_FLOAT:
        return floatstr(v.f);
    }
    return ostd::String("");
}

ostd::String TaggedValue::get_str() const {
    return cs_get_str(*this, get_type());
}

ostd::String Ident::get_str() const {
    return cs_get_str(val, get_valtype());
}

static inline ostd::ConstCharRange cs_get_strr(IdentValue const &v, int type) {
    switch (type) {
        case VAL_STR:
        case VAL_MACRO:
        case VAL_CSTR:
            return ostd::ConstCharRange(v.s, v.len);
        default:
            break;
    }
    return ostd::ConstCharRange();
}

ostd::ConstCharRange TaggedValue::get_strr() const {
    return cs_get_strr(*this, get_type());
}

ostd::ConstCharRange Ident::get_strr() const {
    return cs_get_strr(val, get_valtype());
}

static inline void cs_get_val(IdentValue const &v, int type, TaggedValue &r) {
    switch (type) {
        case VAL_STR:
        case VAL_MACRO:
        case VAL_CSTR: {
            r.set_str(ostd::ConstCharRange(v.s, v.len));
            break;
        }
        case VAL_INT:
            r.set_int(v.i);
            break;
        case VAL_FLOAT:
            r.set_float(v.f);
            break;
        default:
            r.set_null();
            break;
    }
}

void TaggedValue::get_val(TaggedValue &r) const {
    cs_get_val(*this, get_type(), r);
}

void Ident::get_val(TaggedValue &r) const {
    cs_get_val(val, get_valtype(), r);
}

OSTD_EXPORT bool code_is_empty(Bytecode const *code) {
    if (!code) {
        return true;
    }
    return (
        *reinterpret_cast<ostd::Uint32 const *>(code) & CODE_OP_MASK
    ) == CODE_EXIT;
}

bool TaggedValue::code_is_empty() const {
    if (get_type() != VAL_CODE) {
        return true;
    }
    return cscript::code_is_empty(code);
}

static inline bool cs_get_bool(ostd::ConstCharRange s) {
    if (s.empty()) {
        return false;
    }
    ostd::ConstCharRange end = s;
    CsInt ival = cs_parse_int(end, &end);
    if (end.empty()) {
        return !!ival;
    }
    end = s;
    CsFloat fval = cs_parse_float(end, &end);
    if (end.empty()) {
        return !!fval;
    }
    return true;
}

bool TaggedValue::get_bool() const {
    switch (get_type()) {
        case VAL_FLOAT:
            return f != 0;
        case VAL_INT:
            return i != 0;
        case VAL_STR:
        case VAL_MACRO:
        case VAL_CSTR:
            return cs_get_bool(ostd::ConstCharRange(s, len));
        default:
            return false;
    }
}

void Ident::get_cstr(TaggedValue &v) const {
    switch (get_valtype()) {
        case VAL_MACRO:
            v.set_macro(val.code, val.len);
            break;
        case VAL_STR:
        case VAL_CSTR:
            v.set_cstr(ostd::ConstCharRange(val.s, val.len));
            break;
        case VAL_INT:
            v.set_str(ostd::move(intstr(val.i)));
            break;
        case VAL_FLOAT:
            v.set_str(ostd::move(floatstr(val.f)));
            break;
        default:
            v.set_cstr("");
            break;
    }
}

void Ident::get_cval(TaggedValue &v) const {
    switch (get_valtype()) {
        case VAL_MACRO:
            v.set_macro(val.code, val.len);
            break;
        case VAL_STR:
        case VAL_CSTR:
            v.set_cstr(ostd::ConstCharRange(val.s, val.len));
            break;
        case VAL_INT:
            v.set_int(val.i);
            break;
        case VAL_FLOAT:
            v.set_float(val.f);
            break;
        default:
            v.set_null();
            break;
    }
}

void Ident::clean_code() {
    ostd::Uint32 *bcode = reinterpret_cast<ostd::Uint32 *>(code);
    if (bcode) {
        bcode_decr(bcode);
        code = nullptr;
    }
}

void Ident::push_arg(TaggedValue const &v, IdentStack &st, bool um) {
    st.val = val;
    st.valtype = valtype;
    st.next = stack;
    stack = &st;
    set_value(v);
    clean_code();
    if (um) {
        flags &= ~IDF_UNKNOWN;
    }
}

void Ident::pop_arg() {
    if (!stack) {
        return;
    }
    IdentStack *st = stack;
    if (get_valtype() == VAL_STR) {
        delete[] val.s;
    }
    set_value(*stack);
    clean_code();
    stack = st->next;
}

void Ident::undo_arg(IdentStack &st) {
    IdentStack *prev = stack;
    st.val = val;
    st.valtype = valtype;
    st.next = prev;
    stack = prev->next;
    set_value(*prev);
    clean_code();
}

void Ident::redo_arg(IdentStack const &st) {
    IdentStack *prev = st.next;
    prev->val = val;
    prev->valtype = valtype;
    stack = prev;
    set_value(st);
    clean_code();
}

void Ident::push_alias(IdentStack &stack) {
    if (type == ID_ALIAS && index >= MaxArguments) {
        push_arg(null_value, stack);
    }
}

void Ident::pop_alias() {
    if (type == ID_ALIAS && index >= MaxArguments) {
        pop_arg();
    }
}

void Ident::set_arg(CsState &cs, TaggedValue &v) {
    if (cs.stack->usedargs & (1 << index)) {
        if (get_valtype() == VAL_STR) {
            delete[] val.s;
        }
        set_value(v);
        clean_code();
    } else {
        push_arg(v, cs.stack->argstack[index], false);
        cs.stack->usedargs |= 1 << index;
    }
}

void Ident::set_alias(CsState &cs, TaggedValue &v) {
    if (get_valtype() == VAL_STR) {
        delete[] val.s;
    }
    set_value(v);
    clean_code();
    flags = (flags & cs.identflags) | cs.identflags;
}

IdentType Ident::get_type() const {
    if (type > ID_ALIAS) {
        return IdentType::unknown;
    }
    return IdentType(type);
}

template<typename SF, typename RF, typename CF>
bool cs_override_var(CsState &cs, Ident *id, SF sf, RF rf, CF cf) {
    if ((cs.identflags & IDF_OVERRIDDEN) || (id->flags & IDF_OVERRIDE)) {
        if (id->flags & IDF_PERSIST) {
            cs_debug_code(cs, "cannot override persistent variable '%s'",
                          id->name);
            return false;
        }
        if (!(id->flags & IDF_OVERRIDDEN)) {
            sf();
            id->flags |= IDF_OVERRIDDEN;
        } else {
            cf();
        }
    } else {
        if (id->flags & IDF_OVERRIDDEN) {
            rf();
            id->flags &= ~IDF_OVERRIDDEN;
        }
        cf();
    }
    return true;
}

void CsState::set_var_int(
    ostd::ConstCharRange name, CsInt v, bool dofunc, bool doclamp
) {
    Ident *id = get_ident(name);
    if (!id || id->is_ivar()) {
        return;
    }
    bool success = cs_override_var(
        *this, id,
        [&id]() { id->overrideval.i = *id->storage.ip; },
        []() {}, []() {}
    );
    if (!success) {
        return;
    }
    if (doclamp) {
        *id->storage.ip = ostd::clamp(v, id->minval, id->maxval);
    } else {
        *id->storage.ip = v;
    }
    if (dofunc) {
        id->changed();
    }
}

void CsState::set_var_float(
    ostd::ConstCharRange name, CsFloat v, bool dofunc, bool doclamp
) {
    Ident *id = get_ident(name);
    if (!id || id->is_fvar()) {
        return;
    }
    bool success = cs_override_var(
        *this, id,
        [&id]() { id->overrideval.f = *id->storage.fp; },
        []() {}, []() {}
    );
    if (!success) {
        return;
    }
    if (doclamp) {
        *id->storage.fp = ostd::clamp(v, id->minvalf, id->maxvalf);
    } else {
        *id->storage.fp = v;
    }
    if (dofunc) {
        id->changed();
    }
}

void CsState::set_var_str(
    ostd::ConstCharRange name, ostd::ConstCharRange v, bool dofunc
) {
    Ident *id = get_ident(name);
    if (!id || id->is_svar()) {
        return;
    }
    bool success = cs_override_var(
        *this, id,
        [&id]() { id->overrideval.s = *id->storage.sp; },
        [&id]() { delete[] id->overrideval.s; },
        [&id]() { delete[] *id->storage.sp; }
    );
    if (!success) {
        return;
    }
    *id->storage.sp = cs_dup_ostr(v);
    if (dofunc) {
        id->changed();
    }
}

ostd::Maybe<CsInt> CsState::get_var_int(ostd::ConstCharRange name) {
    Ident *id = get_ident(name);
    if (!id || id->is_ivar()) {
        return ostd::nothing;
    }
    return *id->storage.ip;
}

ostd::Maybe<CsFloat> CsState::get_var_float(ostd::ConstCharRange name) {
    Ident *id = get_ident(name);
    if (!id || id->is_fvar()) {
        return ostd::nothing;
    }
    return *id->storage.fp;
}

ostd::Maybe<ostd::String> CsState::get_var_str(ostd::ConstCharRange name) {
    Ident *id = get_ident(name);
    if (!id || id->is_svar()) {
        return ostd::nothing;
    }
    return ostd::String(*id->storage.sp);
}

ostd::Maybe<CsInt> CsState::get_var_min_int(ostd::ConstCharRange name) {
    Ident *id = get_ident(name);
    if (!id || id->is_ivar()) {
        return ostd::nothing;
    }
    return id->minval;
}

ostd::Maybe<CsInt> CsState::get_var_max_int(ostd::ConstCharRange name) {
    Ident *id = get_ident(name);
    if (!id || id->is_ivar()) {
        return ostd::nothing;
    }
    return id->maxval;
}

ostd::Maybe<CsFloat> CsState::get_var_min_float(ostd::ConstCharRange name) {
    Ident *id = get_ident(name);
    if (!id || id->is_fvar()) {
        return ostd::nothing;
    }
    return id->minvalf;
}

ostd::Maybe<CsFloat> CsState::get_var_max_float(ostd::ConstCharRange name) {
    Ident *id = get_ident(name);
    if (!id || id->is_fvar()) {
        return ostd::nothing;
    }
    return id->maxvalf;
}

ostd::Maybe<ostd::String>
CsState::get_alias_val(ostd::ConstCharRange name) {
    Ident *id = get_ident(name);
    if (!id || id->is_alias()) {
        return ostd::nothing;
    }
    if ((id->index < MaxArguments) && !(stack->usedargs & (1 << id->index))) {
        return ostd::nothing;
    }
    return ostd::move(id->get_str());
}

CsInt cs_clamp_var(CsState &cs, Ident *id, CsInt v) {
    if (v < id->minval) {
        v = id->minval;
    } else if (v > id->maxval) {
        v = id->maxval;
    } else {
        return v;
    }
    cs_debug_code(
        cs,
        (id->flags & IDF_HEX)
            ? (
                (id->minval <= 255)
                    ? "valid range for '%s' is %d..0x%X"
                    : "valid range for '%s' is 0x%X..0x%X"
            )
            : "valid range for '%s' is %d..%d",
        id->name, id->minval, id->maxval
    );
    return v;
}

void CsState::set_var_int_checked(Ident *id, CsInt v) {
    if (id->flags & IDF_READONLY) {
        cs_debug_code(*this, "variable '%s' is read only", id->name);
        return;
    }
    bool success = cs_override_var(
        *this, id,
        [&id]() { id->overrideval.i = *id->storage.ip; },
        []() {}, []() {}
    );
    if (!success) {
        return;
    }
    if ((v < id->minval) || (v > id->maxval)) {
        v = cs_clamp_var(*this, id, v);
    }
    *id->storage.ip = v;
    id->changed();
}

void CsState::set_var_int_checked(Ident *id, TvalRange args) {
    CsInt v = args[0].force_int();
    if ((id->flags & IDF_HEX) && (args.size() > 1)) {
        v = (v << 16) | (args[1].force_int() << 8);
        if (args.size() > 2) {
            v |= args[2].force_int();
        }
    }
    set_var_int_checked(id, v);
}

CsFloat cs_clamp_fvar(CsState &cs, Ident *id, CsFloat v) {
    if (v < id->minvalf) {
        v = id->minvalf;
    } else if (v > id->maxvalf) {
        v = id->maxvalf;
    } else {
        return v;
    }
    cs_debug_code(
        cs, "valid range for '%s' is %s..%s", floatstr(id->minvalf),
        floatstr(id->maxvalf)
    );
    return v;
}

void CsState::set_var_float_checked(Ident *id, CsFloat v) {
    if (id->flags & IDF_READONLY) {
        cs_debug_code(*this, "variable '%s' is read only", id->name);
        return;
    }
    bool success = cs_override_var(
        *this, id,
        [&id]() { id->overrideval.f = *id->storage.fp; },
        []() {}, []() {}
    );
    if (!success) {
        return;
    }
    if ((v < id->minvalf) || (v > id->maxvalf)) {
        v = cs_clamp_fvar(*this, id, v);
    }
    *id->storage.fp = v;
    id->changed();
}

void CsState::set_var_str_checked(Ident *id, ostd::ConstCharRange v) {
    if (id->flags & IDF_READONLY) {
        cs_debug_code(*this, "variable '%s' is read only", id->name);
        return;
    }
    bool success = cs_override_var(
        *this, id,
        [&id]() { id->overrideval.s = *id->storage.sp; },
        [&id]() { delete[] id->overrideval.s; },
        [&id]() { delete[] *id->storage.sp; }
    );
    if (!success) {
        return;
    }
    *id->storage.sp = cs_dup_ostr(v);
    id->changed();
}

static bool cs_add_command(
    CsState &cs, ostd::ConstCharRange name, ostd::ConstCharRange args,
    CmdFunc func, int type = ID_COMMAND
) {
    ostd::Uint32 argmask = 0;
    int nargs = 0;
    for (ostd::ConstCharRange fmt(args); !fmt.empty(); ++fmt) {
        switch (*fmt) {
            case 'i':
            case 'b':
            case 'f':
            case 'F':
            case 't':
            case 'T':
            case 'E':
            case 'N':
            case 'D':
                if (nargs < MaxArguments) {
                    nargs++;
                }
                break;
            case 'S':
            case 's':
            case 'e':
            case 'r':
            case '$':
                if (nargs < MaxArguments) {
                    argmask |= 1 << nargs;
                    nargs++;
                }
                break;
            case '1':
            case '2':
            case '3':
            case '4':
                if (nargs < MaxArguments) {
                    fmt.push_front_n(fmt.front() - '0' + 1);
                }
                break;
            case 'C':
            case 'V':
                break;
            default:
                ostd::err.writefln(
                    "builtin %s declared with illegal type: %c",
                    name, fmt.front()
                );
                return false;
        }
    }
    cs.add_ident(new Command(type, name, args, argmask, nargs, ostd::move(func)));
    return true;
}

bool CsState::add_command(
    ostd::ConstCharRange name, ostd::ConstCharRange args, CmdFunc func
) {
    return cs_add_command(*this, name, args, ostd::move(func));
}

void cs_init_lib_io(CsState &cs) {
    cs_add_command(cs, "exec", "sb", [&cs](TvalRange args, TaggedValue &res) {
        auto file = args[0].get_strr();
        bool ret = cs.run_file(file);
        if (!ret) {
            if (args[1].get_int()) {
                ostd::err.writefln("could not run file \"%s\"", file);
            }
            res.set_int(0);
        } else {
            res.set_int(1);
        }
    });

    cs_add_command(cs, "echo", "C", [](TvalRange args, TaggedValue &) {
        ostd::writeln(args[0].get_strr());
    });
}

static inline void cs_set_iter(Ident &id, CsInt i, IdentStack &stack) {
    if (id.stack == &stack) {
        if (id.get_valtype() != VAL_INT) {
            if (id.get_valtype() == VAL_STR) {
                delete[] id.val.s;
                id.val.s = nullptr;
                id.val.len = 0;
            }
            id.clean_code();
            id.valtype = VAL_INT;
        }
        id.val.i = i;
        return;
    }
    TaggedValue v;
    v.set_int(i);
    id.push_arg(v, stack);
}

static inline void cs_do_loop(
    CsState &cs, Ident &id, CsInt offset, CsInt n, CsInt step,
    Bytecode *cond, Bytecode *body
) {
    if (n <= 0 || !id.is_alias()) {
        return;
    }
    IdentStack stack;
    for (CsInt i = 0; i < n; ++i) {
        cs_set_iter(id, offset + i * step, stack);
        if (cond && !cs.run_bool(cond)) {
            break;
        }
        cs.run_int(body);
    }
    id.pop_arg();
}

static inline void cs_loop_conc(
    CsState &cs, TaggedValue &res, Ident &id, CsInt offset, CsInt n,
    CsInt step, Bytecode *body, bool space
) {
    if (n <= 0 || !id.is_alias()) {
        return;
    }
    IdentStack stack;
    ostd::Vector<char> s;
    for (CsInt i = 0; i < n; ++i) {
        cs_set_iter(id, offset + i * step, stack);
        TaggedValue v;
        cs.run_ret(body, v);
        ostd::String vstr = ostd::move(v.get_str());
        if (space && i) {
            s.push(' ');
        }
        s.push_n(vstr.data(), vstr.size());
        v.cleanup();
    }
    if (n > 0) {
        id.pop_arg();
    }
    s.push('\0');
    ostd::Size len = s.size() - 1;
    res.set_mstr(ostd::CharRange(s.disown(), len));
}

void cs_init_lib_base(CsState &cs) {
    cs_add_command(cs, "do", "e", [&cs](TvalRange args, TaggedValue &res) {
        cs.run_ret(args[0].get_code(), res);
    }, ID_DO);

    cs_add_command(cs, "doargs", "e", [&cs](TvalRange args, TaggedValue &res) {
        if (cs.stack != &cs.noalias) {
            cs_do_args(cs, [&]() { cs.run_ret(args[0].get_code(), res); });
        } else {
            cs.run_ret(args[0].get_code(), res);
        }
    }, ID_DOARGS);

    cs_add_command(cs, "if", "tee", [&cs](TvalRange args, TaggedValue &res) {
        cs.run_ret((args[0].get_bool() ? args[1] : args[2]).get_code(), res);
    }, ID_IF);

    cs_add_command(cs, "result", "T", [](TvalRange args, TaggedValue &res) {
        TaggedValue &v = args[0];
        res = v;
        v.set_null();
    }, ID_RESULT);

    cs_add_command(cs, "!", "t", [](TvalRange args, TaggedValue &res) {
        res.set_int(!args[0].get_bool());
    }, ID_NOT);

    cs_add_command(cs, "&&", "E1V", [&cs](TvalRange args, TaggedValue &res) {
        if (args.empty()) {
            res.set_int(1);
        } else {
            for (ostd::Size i = 0; i < args.size(); ++i) {
                if (i) {
                    res.cleanup();
                }
                if (args[i].get_type() == VAL_CODE) {
                    cs.run_ret(args[i].code, res);
                } else {
                    res = args[i];
                }
                if (!res.get_bool()) {
                    break;
                }
            }
        }
    }, ID_AND);

    cs_add_command(cs, "||", "E1V", [&cs](TvalRange args, TaggedValue &res) {
        if (args.empty()) {
            res.set_int(0);
        } else {
            for (ostd::Size i = 0; i < args.size(); ++i) {
                if (i) {
                    res.cleanup();
                }
                if (args[i].get_type() == VAL_CODE) {
                    cs.run_ret(args[i].code, res);
                } else {
                    res = args[i];
                }
                if (res.get_bool()) {
                    break;
                }
            }
        }
    }, ID_OR);

    cs_add_command(cs, "?", "tTT", [](TvalRange args, TaggedValue &res) {
        res.set(args[0].get_bool() ? args[1] : args[2]);
    });

    cs_add_command(cs, "cond", "ee2V", [&cs](TvalRange args, TaggedValue &res) {
        for (ostd::Size i = 0; i < args.size(); i += 2) {
            if ((i + 1) < args.size()) {
                if (cs.run_bool(args[i].code)) {
                    cs.run_ret(args[i + 1].code, res);
                    break;
                }
            } else {
                cs.run_ret(args[i].code, res);
                break;
            }
        }
    });

    cs_add_command(cs, "case", "ite2V", [&cs](TvalRange args, TaggedValue &res) {
        CsInt val = args[0].get_int();
        for (ostd::Size i = 1; (i + 1) < args.size(); i += 2) {
            if ((args[i].get_type() == VAL_NULL) || (args[i].get_int() == val)) {
                cs.run_ret(args[i + 1].code, res);
                return;
            }
        }
    });

    cs_add_command(cs, "casef", "fte2V", [&cs](TvalRange args, TaggedValue &res) {
        CsFloat val = args[0].get_float();
        for (ostd::Size i = 1; (i + 1) < args.size(); i += 2) {
            if ((args[i].get_type() == VAL_NULL) || (args[i].get_float() == val)) {
                cs.run_ret(args[i + 1].code, res);
                return;
            }
        }
    });

    cs_add_command(cs, "cases", "ste2V", [&cs](TvalRange args, TaggedValue &res) {
        ostd::String val = args[0].get_str();
        for (ostd::Size i = 1; (i + 1) < args.size(); i += 2) {
            if ((args[i].get_type() == VAL_NULL) || (args[i].get_str() == val)) {
                cs.run_ret(args[i + 1].code, res);
                return;
            }
        }
    });

    cs_add_command(cs, "pushif", "rTe", [&cs](TvalRange args, TaggedValue &res) {
        Ident *id = args[0].get_ident();
        TaggedValue &v = args[1];
        Bytecode *code = args[2].get_code();
        if (!id->is_alias() || (id->index < MaxArguments)) {
            return;
        }
        if (v.get_bool()) {
            IdentStack stack;
            id->push_arg(v, stack);
            v.set_null();
            cs.run_ret(code, res);
            id->pop_arg();
        }
    });

    cs_add_command(cs, "loop", "rie", [&cs](TvalRange args, TaggedValue &) {
        cs_do_loop(
            cs, *args[0].get_ident(), 0, args[1].get_int(), 1, nullptr,
            args[2].get_code()
        );
    });

    cs_add_command(cs, "loop+", "riie", [&cs](TvalRange args, TaggedValue &) {
        cs_do_loop(
            cs, *args[0].get_ident(), args[1].get_int(), args[2].get_int(), 1,
            nullptr, args[3].get_code()
        );
    });

    cs_add_command(cs, "loop*", "riie", [&cs](TvalRange args, TaggedValue &) {
        cs_do_loop(
            cs, *args[0].get_ident(), 0, args[1].get_int(), args[2].get_int(),
            nullptr, args[3].get_code()
        );
    });

    cs_add_command(cs, "loop+*", "riiie", [&cs](TvalRange args, TaggedValue &) {
        cs_do_loop(
            cs, *args[0].get_ident(), args[1].get_int(), args[3].get_int(),
            args[2].get_int(), nullptr, args[4].get_code()
        );
    });

    cs_add_command(cs, "loopwhile", "riee", [&cs](TvalRange args, TaggedValue &) {
        cs_do_loop(
            cs, *args[0].get_ident(), 0, args[1].get_int(), 1,
            args[2].get_code(), args[3].get_code()
        );
    });

    cs_add_command(cs, "loopwhile+", "riiee", [&cs](TvalRange args, TaggedValue &) {
        cs_do_loop(
            cs, *args[0].get_ident(), args[1].get_int(), args[2].get_int(), 1,
            args[3].get_code(), args[4].get_code()
        );
    });

    cs_add_command(cs, "loopwhile*", "riiee", [&cs](TvalRange args, TaggedValue &) {
        cs_do_loop(
            cs, *args[0].get_ident(), 0, args[2].get_int(), args[1].get_int(),
            args[3].get_code(), args[4].get_code()
        );
    });

    cs_add_command(cs, "loopwhile+*", "riiiee", [&cs](TvalRange args, TaggedValue &) {
        cs_do_loop(
            cs, *args[0].get_ident(), args[1].get_int(), args[3].get_int(),
            args[2].get_int(), args[4].get_code(), args[5].get_code()
        );
    });

    cs_add_command(cs, "while", "ee", [&cs](TvalRange args, TaggedValue &) {
        Bytecode *cond = args[0].get_code(), *body = args[1].get_code();
        while (cs.run_bool(cond)) {
            cs.run_int(body);
        }
    });

    cs_add_command(cs, "loopconcat", "rie", [&cs](TvalRange args, TaggedValue &res) {
        cs_loop_conc(
            cs, res, *args[0].get_ident(), 0, args[1].get_int(), 1,
            args[2].get_code(), true
        );
    });

    cs_add_command(cs, "loopconcat+", "riie", [&cs](TvalRange args, TaggedValue &res) {
        cs_loop_conc(
            cs, res, *args[0].get_ident(), args[1].get_int(), args[2].get_int(), 1,
            args[3].get_code(), true
        );
    });

    cs_add_command(cs, "loopconcat*", "riie", [&cs](TvalRange args, TaggedValue &res) {
        cs_loop_conc(
            cs, res, *args[0].get_ident(), 0, args[2].get_int(), args[1].get_int(),
            args[3].get_code(), true
        );
    });

    cs_add_command(cs, "loopconcat+*", "riiie", [&cs](TvalRange args, TaggedValue &res) {
        cs_loop_conc(
            cs, res, *args[0].get_ident(), args[1].get_int(), args[3].get_int(),
            args[2].get_int(), args[4].get_code(), true
        );
    });

    cs_add_command(cs, "loopconcatword", "rie", [&cs](TvalRange args, TaggedValue &res) {
        cs_loop_conc(
            cs, res, *args[0].get_ident(), 0, args[1].get_int(), 1,
            args[2].get_code(), false
        );
    });

    cs_add_command(cs, "loopconcatword+", "riie", [&cs](TvalRange args, TaggedValue &res) {
        cs_loop_conc(
            cs, res, *args[0].get_ident(), args[1].get_int(), args[2].get_int(), 1,
            args[3].get_code(), false
        );
    });

    cs_add_command(cs, "loopconcatword*", "riie", [&cs](TvalRange args, TaggedValue &res) {
        cs_loop_conc(
            cs, res, *args[0].get_ident(), 0, args[2].get_int(), args[1].get_int(),
            args[3].get_code(), false
        );
    });

    cs_add_command(cs, "loopconcatword+*", "riiie", [&cs](TvalRange args, TaggedValue &res) {
        cs_loop_conc(
            cs, res, *args[0].get_ident(), args[1].get_int(), args[3].get_int(),
            args[2].get_int(), args[4].get_code(), false
        );
    });

    cs_add_command(cs, "nodebug", "e", [&cs](TvalRange args, TaggedValue &res) {
        ++cs.nodebug;
        cs.run_ret(args[0].get_code(), res);
        --cs.nodebug;
    });

    cs_add_command(cs, "push", "rTe", [&cs](TvalRange args, TaggedValue &res) {
        Ident *id = args[0].get_ident();
        if (!id->is_alias() || (id->index < MaxArguments)) {
            return;
        }
        IdentStack stack;
        TaggedValue &v = args[1];
        id->push_arg(v, stack);
        v.set_null();
        cs.run_ret(args[2].get_code(), res);
        id->pop_arg();
    });

    cs_add_command(cs, "local", nullptr, nullptr, ID_LOCAL);

    cs_add_command(cs, "resetvar", "s", [&cs](TvalRange args, TaggedValue &res) {
        res.set_int(cs.reset_var(args[0].get_strr()));
    });

    cs_add_command(cs, "alias", "sT", [&cs](TvalRange args, TaggedValue &) {
        TaggedValue &v = args[1];
        cs.set_alias(args[0].get_strr(), v);
        v.set_null();
    });

    cs_add_command(cs, "getvarmin", "s", [&cs](TvalRange args, TaggedValue &res) {
        res.set_int(cs.get_var_min_int(args[0].get_strr()).value_or(0));
    });
    cs_add_command(cs, "getvarmax", "s", [&cs](TvalRange args, TaggedValue &res) {
        res.set_int(cs.get_var_max_int(args[0].get_strr()).value_or(0));
    });
    cs_add_command(cs, "getfvarmin", "s", [&cs](TvalRange args, TaggedValue &res) {
        res.set_float(cs.get_var_min_float(args[0].get_strr()).value_or(0.0f));
    });
    cs_add_command(cs, "getfvarmax", "s", [&cs](TvalRange args, TaggedValue &res) {
        res.set_float(cs.get_var_max_float(args[0].get_strr()).value_or(0.0f));
    });

    cs_add_command(cs, "identexists", "s", [&cs](TvalRange args, TaggedValue &res) {
        res.set_int(cs.have_ident(args[0].get_strr()));
    });

    cs_add_command(cs, "getalias", "s", [&cs](TvalRange args, TaggedValue &res) {
        res.set_str(ostd::move(cs.get_alias_val(args[0].get_strr()).value_or("")));
    });
}

void cs_init_lib_math(CsState &cs);
void cs_init_lib_string(CsState &cs);
void cs_init_lib_list(CsState &cs);

OSTD_EXPORT void init_libs(CsState &cs, int libs) {
    if (libs & CS_LIB_IO) {
        cs_init_lib_io(cs);
    }
    if (libs & CS_LIB_MATH) {
        cs_init_lib_math(cs);
    }
    if (libs & CS_LIB_STRING) {
        cs_init_lib_string(cs);
    }
    if (libs & CS_LIB_LIST) {
        cs_init_lib_list(cs);
    }
}

} /* namespace cscript */