#include <cubescript/cubescript.hh>
#include "cs_vm.hh"

#include <iterator>

namespace cscript {

bool cs_check_num(std::string_view 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;
    }
}

LIBCUBESCRIPT_EXPORT void cs_state::clear_override(cs_ident &id) {
    if (!(id.get_flags() & CS_IDF_OVERRIDDEN)) {
        return;
    }
    switch (id.get_type()) {
        case cs_ident_type::ALIAS: {
            cs_alias_impl &a = static_cast<cs_alias_impl &>(id);
            a.clean_code();
            a.get_value().set_str("");
            break;
        }
        case cs_ident_type::IVAR: {
            cs_ivar_impl &iv = static_cast<cs_ivar_impl &>(id);
            iv.set_value(iv.p_overrideval);
            iv.changed(*this);
            break;
        }
        case cs_ident_type::FVAR: {
            cs_fvar_impl &fv = static_cast<cs_fvar_impl &>(id);
            fv.set_value(fv.p_overrideval);
            fv.changed(*this);
            break;
        }
        case cs_ident_type::SVAR: {
            cs_svar_impl &sv = static_cast<cs_svar_impl &>(id);
            sv.set_value(sv.p_overrideval);
            sv.changed(*this);
            break;
        }
        default:
            break;
    }
    id.p_impl->p_flags &= ~CS_IDF_OVERRIDDEN;
}

LIBCUBESCRIPT_EXPORT void cs_state::clear_overrides() {
    for (auto &p: p_state->idents) {
        clear_override(*(p.second));
    }
}

LIBCUBESCRIPT_EXPORT cs_ident *cs_state::add_ident(
    cs_ident *id, cs_ident_impl *impl
) {
    if (!id) {
        return nullptr;
    }
    id->p_impl = impl;
    p_state->idents[id->get_name()] = id;
    static_cast<cs_ident_impl *>(impl)->p_index = p_state->identmap.size();
    p_state->identmap.push_back(id);
    return p_state->identmap.back();
}

LIBCUBESCRIPT_EXPORT cs_ident *cs_state::new_ident(std::string_view name, int flags) {
    cs_ident *id = get_ident(name);
    if (!id) {
        if (cs_check_num(name)) {
            throw cs_error(
                *this, "number %s is not a valid identifier name", name.data()
            );
        }
        auto *inst = p_state->create<cs_alias_impl>(
            *this, cs_strref{p_state, name}, flags
        );
        id = add_ident(inst, inst);
    }
    return id;
}

LIBCUBESCRIPT_EXPORT cs_ident *cs_state::force_ident(cs_value &v) {
    switch (v.get_type()) {
        case cs_value_type::IDENT:
            return v.get_ident();
        case cs_value_type::STRING: {
            cs_ident *id = new_ident(v.get_str());
            v.set_ident(id);
            return id;
        }
        default:
            break;
    }
    v.set_ident(p_state->identmap[DummyIdx]);
    return p_state->identmap[DummyIdx];
}

LIBCUBESCRIPT_EXPORT cs_ident *cs_state::get_ident(std::string_view name) {
    auto id = p_state->idents.find(name);
    if (id != p_state->idents.end()) {
        return id->second;
    }
    return nullptr;
}

LIBCUBESCRIPT_EXPORT cs_alias *cs_state::get_alias(std::string_view name) {
    auto id = get_ident(name);
    if (!id || !id->is_alias()) {
        return nullptr;
    }
    return static_cast<cs_alias *>(id);
}

LIBCUBESCRIPT_EXPORT bool cs_state::have_ident(std::string_view name) {
    return p_state->idents.find(name) != p_state->idents.end();
}

LIBCUBESCRIPT_EXPORT std::span<cs_ident *> cs_state::get_idents() {
    return std::span<cs_ident *>{
        p_state->identmap.data(),
        p_state->identmap.size()
    };
}

LIBCUBESCRIPT_EXPORT std::span<cs_ident const *> cs_state::get_idents() const {
    auto ptr = const_cast<cs_ident const **>(p_state->identmap.data());
    return std::span<cs_ident const *>{ptr, p_state->identmap.size()};
}

LIBCUBESCRIPT_EXPORT cs_ivar *cs_state::new_ivar(
    std::string_view n, cs_int m, cs_int x, cs_int v, cs_var_cb f, int flags
) {
    auto *iv = p_state->create<cs_ivar_impl>(
        cs_strref{p_state, n}, m, x, v, std::move(f), flags
    );
    add_ident(iv, iv);
    return iv;
}

LIBCUBESCRIPT_EXPORT cs_fvar *cs_state::new_fvar(
    std::string_view n, cs_float m, cs_float x, cs_float v, cs_var_cb f, int flags
) {
    auto *fv = p_state->create<cs_fvar_impl>(
        cs_strref{p_state, n}, m, x, v, std::move(f), flags
    );
    add_ident(fv, fv);
    return fv;
}

LIBCUBESCRIPT_EXPORT cs_svar *cs_state::new_svar(
    std::string_view n, std::string_view v, cs_var_cb f, int flags
) {
    auto *sv = p_state->create<cs_svar_impl>(
        cs_strref{p_state, n}, cs_strref{p_state, v},
        cs_strref{p_state, ""}, std::move(f), flags
    );
    add_ident(sv, sv);
    return sv;
}

LIBCUBESCRIPT_EXPORT void cs_state::reset_var(std::string_view name) {
    cs_ident *id = get_ident(name);
    if (!id) {
        throw cs_error(*this, "variable %s does not exist", name.data());
    }
    if (id->get_flags() & CS_IDF_READONLY) {
        throw cs_error(*this, "variable %s is read only", name.data());
    }
    clear_override(*id);
}

LIBCUBESCRIPT_EXPORT void cs_state::touch_var(std::string_view name) {
    cs_ident *id = get_ident(name);
    if (id && id->is_var()) {
        static_cast<cs_var_impl *>(id->p_impl)->changed(*this);
    }
}

LIBCUBESCRIPT_EXPORT void cs_state::set_alias(std::string_view name, cs_value v) {
    cs_ident *id = get_ident(name);
    if (id) {
        switch (id->get_type()) {
            case cs_ident_type::ALIAS: {
                cs_alias_impl *a = static_cast<cs_alias_impl *>(id);
                if (a->get_index() < MaxArguments) {
                    a->set_arg(*this, v);
                } else {
                    a->set_alias(*this, v);
                }
                return;
            }
            case cs_ident_type::IVAR:
                set_var_int_checked(static_cast<cs_ivar *>(id), v.get_int());
                break;
            case cs_ident_type::FVAR:
                set_var_float_checked(static_cast<cs_fvar *>(id), v.get_float());
                break;
            case cs_ident_type::SVAR:
                set_var_str_checked(static_cast<cs_svar *>(id), v.get_str());
                break;
            default:
                throw cs_error(
                    *this, "cannot redefine builtin %s with an alias",
                    id->get_name().data()
                );
        }
    } else if (cs_check_num(name)) {
        throw cs_error(*this, "cannot alias number %s", name.data());
    } else {
        auto *a = p_state->create<cs_alias_impl>(
            *this, cs_strref{p_state, name}, std::move(v), identflags
        );
        add_ident(a, a);
    }
}

LIBCUBESCRIPT_EXPORT void cs_state::print_var(cs_var const &v) const {
    if (p_state->varprintf) {
        p_state->varprintf(*this, v);
    }
}

LIBCUBESCRIPT_EXPORT cs_value cs_alias::get_value() const {
    return static_cast<cs_alias_impl const *>(this)->p_val;
}

void cs_alias::get_cval(cs_value &v) const {
    auto *imp = static_cast<cs_alias_impl const *>(this);
    switch (imp->p_val.get_type()) {
        case cs_value_type::STRING:
            v = imp->p_val;
            break;
        case cs_value_type::INT:
            v.set_int(imp->p_val.get_int());
            break;
        case cs_value_type::FLOAT:
            v.set_float(imp->p_val.get_float());
            break;
        default:
            v.set_none();
            break;
    }
}

int cs_ident::get_raw_type() const {
    return p_impl->p_type;
}

cs_ident_type cs_ident::get_type() const {
    if (p_impl->p_type > ID_ALIAS) {
        return cs_ident_type::SPECIAL;
    }
    return cs_ident_type(p_impl->p_type);
}

std::string_view cs_ident::get_name() const {
    return p_impl->p_name;
}

int cs_ident::get_flags() const {
    return p_impl->p_flags;
}

int cs_ident::get_index() const {
    return p_impl->p_index;
}

template<typename SF>
static inline void cs_override_var(cs_state &cs, cs_var *v, int &vflags, SF sf) {
    if ((cs.identflags & CS_IDF_OVERRIDDEN) || (vflags & CS_IDF_OVERRIDE)) {
        if (vflags & CS_IDF_PERSIST) {
            throw cs_error(
                cs, "cannot override persistent variable '%s'",
                v->get_name().data()
            );
        }
        if (!(vflags & CS_IDF_OVERRIDDEN)) {
            sf();
            vflags |= CS_IDF_OVERRIDDEN;
        }
    } else {
        if (vflags & CS_IDF_OVERRIDDEN) {
            vflags &= ~CS_IDF_OVERRIDDEN;
        }
    }
}

LIBCUBESCRIPT_EXPORT void cs_state::set_var_int(
    std::string_view name, cs_int v, bool dofunc, bool doclamp
) {
    cs_ident *id = get_ident(name);
    if (!id || id->is_ivar()) {
        return;
    }
    cs_ivar_impl *iv = static_cast<cs_ivar_impl *>(id);
    cs_override_var(
        *this, iv, iv->p_flags,
        [&iv]() { iv->p_overrideval = iv->get_value(); }
    );
    if (doclamp) {
        iv->set_value(std::clamp(v, iv->get_val_min(), iv->get_val_max()));
    } else {
        iv->set_value(v);
    }
    if (dofunc) {
        iv->changed(*this);
    }
}

LIBCUBESCRIPT_EXPORT void cs_state::set_var_float(
    std::string_view name, cs_float v, bool dofunc, bool doclamp
) {
    cs_ident *id = get_ident(name);
    if (!id || id->is_fvar()) {
        return;
    }
    cs_fvar_impl *fv = static_cast<cs_fvar_impl *>(id);
    cs_override_var(
        *this, fv, fv->p_flags,
        [&fv]() { fv->p_overrideval = fv->get_value(); }
    );
    if (doclamp) {
        fv->set_value(std::clamp(v, fv->get_val_min(), fv->get_val_max()));
    } else {
        fv->set_value(v);
    }
    if (dofunc) {
        fv->changed(*this);
    }
}

LIBCUBESCRIPT_EXPORT void cs_state::set_var_str(
    std::string_view name, std::string_view v, bool dofunc
) {
    cs_ident *id = get_ident(name);
    if (!id || id->is_svar()) {
        return;
    }
    cs_svar_impl *sv = static_cast<cs_svar_impl *>(id);
    cs_override_var(
        *this, sv, sv->p_flags,
        [&sv]() { sv->p_overrideval = sv->get_value(); }
    );
    sv->set_value(cs_strref{p_state, v});
    if (dofunc) {
        sv->changed(*this);
    }
}

LIBCUBESCRIPT_EXPORT std::optional<cs_int>
cs_state::get_var_int(std::string_view name) {
    cs_ident *id = get_ident(name);
    if (!id || id->is_ivar()) {
        return std::nullopt;
    }
    return static_cast<cs_ivar *>(id)->get_value();
}

LIBCUBESCRIPT_EXPORT std::optional<cs_float>
cs_state::get_var_float(std::string_view name) {
    cs_ident *id = get_ident(name);
    if (!id || id->is_fvar()) {
        return std::nullopt;
    }
    return static_cast<cs_fvar *>(id)->get_value();
}

LIBCUBESCRIPT_EXPORT std::optional<cs_strref>
cs_state::get_var_str(std::string_view name) {
    cs_ident *id = get_ident(name);
    if (!id || id->is_svar()) {
        return std::nullopt;
    }
    return cs_strref{p_state, static_cast<cs_svar *>(id)->get_value()};
}

LIBCUBESCRIPT_EXPORT std::optional<cs_int>
cs_state::get_var_min_int(std::string_view name) {
    cs_ident *id = get_ident(name);
    if (!id || id->is_ivar()) {
        return std::nullopt;
    }
    return static_cast<cs_ivar *>(id)->get_val_min();
}

LIBCUBESCRIPT_EXPORT std::optional<cs_int>
cs_state::get_var_max_int(std::string_view name) {
    cs_ident *id = get_ident(name);
    if (!id || id->is_ivar()) {
        return std::nullopt;
    }
    return static_cast<cs_ivar *>(id)->get_val_max();
}

LIBCUBESCRIPT_EXPORT std::optional<cs_float>
cs_state::get_var_min_float(std::string_view name) {
    cs_ident *id = get_ident(name);
    if (!id || id->is_fvar()) {
        return std::nullopt;
    }
    return static_cast<cs_fvar *>(id)->get_val_min();
}

LIBCUBESCRIPT_EXPORT std::optional<cs_float>
cs_state::get_var_max_float(std::string_view name) {
    cs_ident *id = get_ident(name);
    if (!id || id->is_fvar()) {
        return std::nullopt;
    }
    return static_cast<cs_fvar *>(id)->get_val_max();
}

LIBCUBESCRIPT_EXPORT std::optional<cs_strref>
cs_state::get_alias_val(std::string_view name) {
    cs_alias *a = get_alias(name);
    if (!a) {
        return std::nullopt;
    }
    if ((a->get_index() < MaxArguments) && !ident_is_used_arg(a, *this)) {
        return std::nullopt;
    }
    return a->get_value().get_str();
}

cs_int cs_clamp_var(cs_state &cs, cs_ivar *iv, cs_int v) {
    if (v < iv->get_val_min()) {
        v = iv->get_val_min();
    } else if (v > iv->get_val_max()) {
        v = iv->get_val_max();
    } else {
        return v;
    }
    throw cs_error(
        cs,
        (iv->get_flags() & CS_IDF_HEX)
            ? (
                (iv->get_val_min() <= 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",
        iv->get_name().data(), iv->get_val_min(), iv->get_val_max()
    );
}

LIBCUBESCRIPT_EXPORT void cs_state::set_var_int_checked(cs_ivar *iv, cs_int v) {
    if (iv->get_flags() & CS_IDF_READONLY) {
        throw cs_error(
            *this, "variable '%s' is read only", iv->get_name().data()
        );
    }
    cs_ivar_impl *ivp = static_cast<cs_ivar_impl *>(iv);
    cs_override_var(
        *this, iv, ivp->p_flags,
        [&ivp]() { ivp->p_overrideval = ivp->p_storage; }
    );
    if ((v < iv->get_val_min()) || (v > iv->get_val_max())) {
        v = cs_clamp_var(*this, iv, v);
    }
    iv->set_value(v);
    ivp->changed(*this);
}

LIBCUBESCRIPT_EXPORT void cs_state::set_var_int_checked(
    cs_ivar *iv, std::span<cs_value> args
) {
    cs_int v = args[0].force_int();
    if ((iv->get_flags() & CS_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(iv, v);
}

cs_float cs_clamp_fvar(cs_state &cs, cs_fvar *fv, cs_float v) {
    if (v < fv->get_val_min()) {
        v = fv->get_val_min();
    } else if (v > fv->get_val_max()) {
        v = fv->get_val_max();
    } else {
        return v;
    }
    cs_value vmin{cs}, vmax{cs};
    vmin.set_float(fv->get_val_min());
    vmax.set_float(fv->get_val_max());
    throw cs_error(
        cs, "valid range for '%s' is %s..%s", fv->get_name().data(),
        vmin.force_str(), vmax.force_str()
    );
    return v;
}

LIBCUBESCRIPT_EXPORT void cs_state::set_var_float_checked(cs_fvar *fv, cs_float v) {
    if (fv->get_flags() & CS_IDF_READONLY) {
        throw cs_error(
            *this, "variable '%s' is read only", fv->get_name().data()
        );
    }
    cs_fvar_impl *fvp = static_cast<cs_fvar_impl *>(fv);
    cs_override_var(
        *this, fv, fvp->p_flags,
        [&fvp]() { fvp->p_overrideval = fvp->p_storage; }
    );
    if ((v < fv->get_val_min()) || (v > fv->get_val_max())) {
        v = cs_clamp_fvar(*this, fv, v);
    }
    fv->set_value(v);
    fvp->changed(*this);
}

LIBCUBESCRIPT_EXPORT void cs_state::set_var_str_checked(
    cs_svar *sv, std::string_view v
) {
    if (sv->get_flags() & CS_IDF_READONLY) {
        throw cs_error(
            *this, "variable '%s' is read only", sv->get_name().data()
        );
    }
    cs_svar_impl *svp = static_cast<cs_svar_impl *>(sv);
    cs_override_var(
        *this, sv, svp->p_flags,
        [&svp]() { svp->p_overrideval = svp->p_storage; }
    );
    sv->set_value(cs_strref{p_state, v});
    svp->changed(*this);
}

LIBCUBESCRIPT_EXPORT cs_command *cs_state::new_command(
    std::string_view name, std::string_view args, cs_command_cb func
) {
    int nargs = 0;
    for (auto fmt = args.begin(); fmt != args.end(); ++fmt) {
        switch (*fmt) {
            case 'i':
            case 'b':
            case 'f':
            case 'F':
            case 't':
            case 'T':
            case 'E':
            case 'N':
            case 's':
            case 'e':
            case 'r':
            case '$':
                if (nargs < MaxArguments) {
                    ++nargs;
                }
                break;
            case '1':
            case '2':
            case '3':
            case '4':
                if (nargs < (*fmt - '0')) {
                    return nullptr;
                }
                if ((args.end() - fmt) != 2) {
                    return nullptr;
                }
                if ((fmt[1] != 'C') && (fmt[1] != 'V')) {
                    return nullptr;
                }
                if (nargs < MaxArguments) {
                    fmt -= *fmt - '0' + 1;
                }
                break;
            case 'C':
            case 'V':
                if ((fmt + 1) != args.end()) {
                    return nullptr;
                }
                break;
            default:
                return nullptr;
        }
    }
    auto *cmd = p_state->create<cs_command_impl>(
        cs_strref{p_state, name}, cs_strref{p_state, args}, nargs,
        std::move(func)
    );
    add_ident(cmd, cmd);
    return cmd;
}

} /* namespace cscript */