#include <cubescript/cubescript.hh>

#include <cstdlib>
#include <algorithm>

#include "cs_thread.hh"
#include "cs_error.hh"

namespace cubescript {

static typename error::stack_node *save_stack(state &cs) {
    auto &ts = state_p{cs}.ts();
    builtin_var *dalias = ts.istate->ivar_dbgalias;
    auto dval = std::size_t(std::clamp(
        dalias->value().get_integer(), integer_type(0), integer_type(1000)
    ));
    if (!dval) {
        return nullptr;
    }
    std::size_t depth = 0;
    std::size_t total = ts.callstack.size();
    if (!total) {
        return nullptr;
    }
    auto *st = static_cast<typename error::stack_node *>(ts.istate->alloc(
        nullptr, 0, sizeof(typename error::stack_node) * std::min(total, dval)
    ));
    typename error::stack_node *ret = st, *nd = st;
    ++st;
    for (std::size_t i = total - 1;; --i) {
        auto &lev = ts.callstack[i];
        ++depth;
        if (depth < dval) {
            new (nd) typename error::stack_node{
                nullptr, lev.id, total - depth + 1
            };
            if (i == 0) {
                break;
            }
            nd->next = st;
            nd = st++;
        } else if (i == 0) {
            new (nd) typename error::stack_node{nullptr, lev.id, 1};
            break;
        }
    }
    return ret;
}

LIBCUBESCRIPT_EXPORT error::~error() {
    std::size_t slen = 0;
    for (stack_node const *nd = p_stack; nd; nd = nd->next) {
        ++slen;
    }
    state_p{*p_state}.ts().istate->destroy_array(p_stack, slen);
}

LIBCUBESCRIPT_EXPORT error::error(state &cs, std::string_view msg):
    p_errbeg{}, p_errend{}, p_state{&cs}
{
    char *sp;
    char *buf = state_p{cs}.ts().request_errbuf(msg.size(), sp);
    std::memcpy(buf, msg.data(), msg.size());
    buf[msg.size()] = '\0';
    p_errbeg = sp;
    p_errend = buf + msg.size();
    p_stack = save_stack(cs);
}

LIBCUBESCRIPT_EXPORT error::error(
    state &cs, char const *errbeg, char const *errend
): p_errbeg{errbeg}, p_errend{errend}, p_state{&cs} {
    p_stack = save_stack(cs);
}

} /* namespace cubescript */