#ifndef PK_NO_EXPORT_C_API

#include "pocketpy/pocketpy.hpp"
#include "pocketpy/pocketpy_c.h"

#include <iostream>

namespace pkpy{

#define PK_ASSERT_N_EXTRA_ELEMENTS(n)                                                                                  \
    int __ex_count = count_extra_elements(vm, n);                                                                      \
    if(__ex_count < n) {                                                                                               \
        Str msg = _S("expected at least ", n, " elements, got ", __ex_count);                                          \
        pkpy_error(vm_handle, "StackError", pkpy_string(msg.c_str()));                                                 \
        return false;                                                                                                  \
    }

#define PK_ASSERT_NO_ERROR()                                                                                           \
    if(vm->__c.error != nullptr) return false;

static int count_extra_elements(VM* vm, int n) {
    if(vm->callstack.empty()) { return vm->s_data.size(); }
    assert(!vm->__c.s_view.empty());
    return vm->s_data._sp - vm->__c.s_view.back().end();
}

static PyVar stack_item(VM* vm, int index) {
    PyVar* begin;
    PyVar* end = vm->s_data.end();
    if(vm->callstack.empty()) {
        begin = vm->s_data.begin();
    } else {
        assert(!vm->__c.s_view.empty());
        begin = vm->__c.s_view.back().begin();
    }
    int size = end - begin;
    if(index < 0) index += size;
    assert(index >= 0 && index < size);
    return begin[index];
}

#define PK_PROTECTED(__B)                                                                                              \
    try {                                                                                                              \
        __B                                                                                                            \
    } catch(TopLevelException e) {                                                                                     \
        vm->__c.error = (PyObject*)e.ptr->self;                                                                        \
        return false;                                                                                                  \
    } catch(const std::exception& re) {                                                                                \
        PyObject* e_t = vm->_t(vm->tp_exception);                                                                      \
        vm->__c.error = vm->call(e_t, VAR(re.what())).get();                                                           \
        return false;                                                                                                  \
    }

pkpy_vm* pkpy_new_vm(bool enable_os) { return (pkpy_vm*)new VM(enable_os); }

void pkpy_delete_vm(pkpy_vm* vm) { return delete (VM*)vm; }

bool pkpy_exec(pkpy_vm* vm_handle, const char* source) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PyVar res;
    PK_PROTECTED(
        CodeObject* code = vm->compile(source, "main.py", EXEC_MODE);
        res = vm->_exec(code, vm->_main);
        delete code;    // TODO: _exec may raise, so code may leak
    )
    return res != nullptr;
}

bool pkpy_exec_2(pkpy_vm* vm_handle, const char* source, const char* filename, int mode, const char* module) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PyVar res;
    PyObject* mod;
    PK_PROTECTED(
        if(module == nullptr){ mod = vm->_main;
        }else{
                        mod = vm->_modules[module].get();  // may raise
        }
        CodeObject* code = vm->compile(source, filename, (CompileMode)mode);
        res = vm->_exec(code, mod);
        delete code;    // TODO: _exec may raise, so code may leak
    )
    return res != nullptr;
}

void pkpy_set_main_argv(pkpy_vm* vm_handle, int argc, char** argv) {
    VM* vm = (VM*)vm_handle;
    vm->set_main_argv(argc, argv);
}

bool pkpy_dup(pkpy_vm* vm_handle, int n) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar item = stack_item(vm, n);
        vm->s_data.push(item);
    )
    return true;
}

bool pkpy_pop(pkpy_vm* vm_handle, int n) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(n)
    vm->s_data.shrink(n);
    return true;
}

bool pkpy_pop_top(pkpy_vm* vm_handle) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(1)
    vm->s_data.pop();
    return true;
}

bool pkpy_dup_top(pkpy_vm* vm_handle) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(1)
    vm->s_data.push(vm->s_data.top());
    return true;
}

bool pkpy_rot_two(pkpy_vm* vm_handle) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(2)
    std::swap(vm->s_data.top(), vm->s_data.second());
    return true;
}

int pkpy_stack_size(pkpy_vm* vm_handle) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    if(vm->callstack.empty()) { return vm->s_data.size(); }
    if(vm->__c.s_view.empty()) exit(127);
    return vm->s_data._sp - vm->__c.s_view.back().begin();
}

// int
bool pkpy_push_int(pkpy_vm* vm_handle, int value) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PyVar res;
    PK_PROTECTED(
        // int may overflow so we should protect it
        res = py_var(vm, value);
    )
    vm->s_data.push(res);
    return true;
}

bool pkpy_is_int(pkpy_vm* vm_handle, int i) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        return is_int(stack_item(vm, i));
    )
}

bool pkpy_to_int(pkpy_vm* vm_handle, int i, int* out) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar item = stack_item(vm, i);
        *out = py_cast<int>(vm, item);
    )
    return true;
}

// float
bool pkpy_push_float(pkpy_vm* vm_handle, double value) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PyVar res = py_var(vm, value);
    vm->s_data.push(res);
    return true;
}

bool pkpy_is_float(pkpy_vm* vm_handle, int i) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar item = stack_item(vm, i);
        return is_float(item);
    )
}

bool pkpy_to_float(pkpy_vm* vm_handle, int i, double* out) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar item = stack_item(vm, i);
        *out = py_cast<double>(vm, item);
    )
    return true;
}

// bool
bool pkpy_push_bool(pkpy_vm* vm_handle, bool value) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    vm->s_data.push(value ? vm->True : vm->False);
    return true;
}

bool pkpy_is_bool(pkpy_vm* vm_handle, int i) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar item = stack_item(vm, i);
        return is_type(item, vm->tp_bool);
    )
}

bool pkpy_to_bool(pkpy_vm* vm_handle, int i, bool* out) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar item = stack_item(vm, i);
        *out = py_cast<bool>(vm, item);
    )
    return true;
}

// string
bool pkpy_push_string(pkpy_vm* vm_handle, pkpy_CString value) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PyVar res = py_var(vm, value);
    vm->s_data.push(res);
    return true;
}

bool pkpy_is_string(pkpy_vm* vm_handle, int i) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar item = stack_item(vm, i);
        return is_type(item, vm->tp_str);
    )
}

bool pkpy_to_string(pkpy_vm* vm_handle, int i, pkpy_CString* out) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar item = stack_item(vm, i);
        const Str& s = py_cast<Str&>(vm, item);
        *out = s.c_str();
    )
    return true;
}

// void_p
bool pkpy_push_voidp(pkpy_vm* vm_handle, void* value) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PyVar res = py_var(vm, value);
    vm->s_data.push(res);
    return true;
}

bool pkpy_is_voidp(pkpy_vm* vm_handle, int i) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar item = stack_item(vm, i);
        return vm->is_user_type<VoidP>(item);
    )
}

bool pkpy_to_voidp(pkpy_vm* vm_handle, int i, void** out) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar item = stack_item(vm, i);
        VoidP& vp = py_cast<VoidP&>(vm, item);
        *out = vp.ptr;
    )
    return true;
}

// none
bool pkpy_push_none(pkpy_vm* vm_handle) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    vm->s_data.push(vm->None);
    return true;
}

bool pkpy_is_none(pkpy_vm* vm_handle, int i) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar item = stack_item(vm, i);
        return is_none(item);
    )
}

// null
bool pkpy_push_null(pkpy_vm* vm_handle) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    vm->s_data.push(PY_NULL);
    return true;
}

struct TempViewPopper {
    VM* vm;
    bool used;

    TempViewPopper(VM* vm) : vm(vm), used(false) {}

    void restore() noexcept {
        if(used) return;
        vm->__c.s_view.pop_back();
        used = true;
    }

    ~TempViewPopper() { restore(); }
};

// function
static PyVar c_function_wrapper(VM* vm, ArgsView args) {
    pkpy_CFunction f = lambda_get_userdata<pkpy_CFunction>(args.begin());
    PyVar* curr_sp = vm->s_data._sp;

    vm->__c.s_view.push_back(args);
    TempViewPopper _tvp(vm);
    int retc = f((pkpy_vm*)vm);  // may raise, _tvp will handle this via RAII
    _tvp.restore();

    // propagate_if_errored
    if(vm->__c.error != nullptr) {
        PyObject* e_obj = vm->__c.error;
        vm->__c.error = nullptr;
        vm->_error(e_obj);
        return nullptr;
    }
    assert(retc == vm->s_data._sp - curr_sp);
    if(retc == 0) return vm->None;
    if(retc == 1) return vm->s_data.popx();
    ArgsView ret_view(curr_sp, vm->s_data._sp);
    return py_var(vm, ret_view.to_tuple());
}

bool pkpy_push_function(pkpy_vm* vm_handle, const char* sig, pkpy_CFunction f) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PyVar f_obj;
    PK_PROTECTED(
        f_obj = vm->bind(nullptr, sig, c_function_wrapper, f);
    )
    vm->s_data.push(f_obj);
    return true;
}

// special push
bool pkpy_push_module(pkpy_vm* vm_handle, const char* name) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyObject* module = vm->new_module(name);
        vm->s_data.emplace(module);
    )
    return true;
}

// some opt
bool pkpy_getattr(pkpy_vm* vm_handle, pkpy_CName name) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(1)
    PyVar o = vm->s_data.top();
    o = vm->getattr(o, StrName(name), false);
    if(o == nullptr) return false;
    vm->s_data.top() = o;
    return true;
}

bool pkpy_setattr(pkpy_vm* vm_handle, pkpy_CName name) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(2)
    PyVar a = vm->s_data.top();
    PyVar val = vm->s_data.second();
    PK_PROTECTED(
        vm->setattr(a, StrName(name), val);
    )
    vm->s_data.shrink(2);
    return true;
}

// get global will also get bulitins
bool pkpy_getglobal(pkpy_vm* vm_handle, pkpy_CName name) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PyVar o = vm->_main->attr().try_get(StrName(name));
    if(o == nullptr) {
        o = vm->builtins->attr().try_get(StrName(name));
        if(o == nullptr) return false;
    }
    vm->s_data.push(o);
    return true;
}

bool pkpy_setglobal(pkpy_vm* vm_handle, pkpy_CName name) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(1)
    vm->_main->attr().set(StrName(name), vm->s_data.popx());
    return true;
}

bool pkpy_eval(pkpy_vm* vm_handle, const char* source) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        CodeObject* co = vm->compile(source, "<eval>", EVAL_MODE);
        PyVar ret = vm->_exec(co, vm->_main);
        vm->s_data.push(ret);
        delete co;  // TODO: _exec may raise, so code may leak
    )
    return true;
}

bool pkpy_unpack_sequence(pkpy_vm* vm_handle, int n) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(1)
    auto _lock = vm->gc_scope_lock();
    PK_PROTECTED(
        PyVar _0 = vm->py_iter(vm->s_data.popx());
        for(int i=0; i<n; i++){
            PyVar _1 = vm->py_next(_0);
            if(_1 == vm->StopIteration) vm->ValueError("not enough values to unpack");
            vm->s_data.push(_1);
        }
        if(vm->py_next(_0) != vm->StopIteration) vm->ValueError("too many values to unpack");
    )
    return true;
}

bool pkpy_get_unbound_method(pkpy_vm* vm_handle, pkpy_CName name) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(1)
    PyVar o = vm->s_data.top();
    PyVar self;
    PK_PROTECTED(
        o = vm->get_unbound_method(o, StrName(name), &self);
    )
    vm->s_data.pop();
    vm->s_data.push(o);
    vm->s_data.push(self);
    return true;
}

bool pkpy_py_repr(pkpy_vm* vm_handle) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(1)
    PyVar item = vm->s_data.top();
    PK_PROTECTED(
        item = VAR(vm->py_repr(item));
    )
    vm->s_data.top() = item;
    return true;
}

bool pkpy_py_str(pkpy_vm* vm_handle) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(1)
    PyVar item = vm->s_data.top();
    PK_PROTECTED(
        item = VAR(vm->py_str(item));
    )
    vm->s_data.top() = item;
    return true;
}

bool pkpy_py_import(pkpy_vm* vm_handle, pkpy_CString name) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_PROTECTED(
        PyVar module = vm->py_import(name);
        vm->s_data.push(module);
    )
    return true;
}

/* Error Handling */
bool pkpy_error(pkpy_vm* vm_handle, const char* name, pkpy_CString message) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PyVar e_t = vm->_main->attr().try_get_likely_found(name);
    if(e_t == nullptr) {
        e_t = vm->builtins->attr().try_get_likely_found(name);
        if(e_t == nullptr) {
            e_t = vm->_t(vm->tp_exception);
            std::cerr << "[warning] pkpy_error(): " << Str(name).escape() << " not found, fallback to 'Exception'"
                      << std::endl;
        }
    }
    vm->__c.error = vm->call(e_t, VAR(message)).get();
    return false;
}

bool pkpy_check_error(pkpy_vm* vm_handle) {
    VM* vm = (VM*)vm_handle;
    return vm->__c.error != nullptr;
}

bool pkpy_clear_error(pkpy_vm* vm_handle, char** message) {
    VM* vm = (VM*)vm_handle;
    // no error
    if(vm->__c.error == nullptr) return false;
    Exception& e = vm->__c.error->as<Exception>();
    if(message != nullptr)
        *message = strdup(e.summary().c_str());
    else
        std::cout << e.summary() << std::endl;
    vm->__c.error = nullptr;
    if(vm->callstack.empty()) {
        vm->s_data.clear();
    } else {
        if(vm->__c.s_view.empty()) exit(127);
        vm->s_data.reset(vm->__c.s_view.back().end());
    }
    return true;
}

bool pkpy_vectorcall(pkpy_vm* vm_handle, int argc) {
    VM* vm = (VM*)vm_handle;
    PK_ASSERT_NO_ERROR()
    PK_ASSERT_N_EXTRA_ELEMENTS(argc + 2)
    PyVar res;
    PK_PROTECTED(
        res = vm->vectorcall(argc);
    )
    vm->s_data.push(res);
    return true;
}

/*****************************************************************/
void pkpy_free(void* p) { std::free(p); }

pkpy_CName pkpy_name(const char* name) { return StrName(name).index; }

pkpy_CString pkpy_name_to_string(pkpy_CName name) { return StrName(name).c_str(); }

void pkpy_set_output_handler(pkpy_vm* vm_handle, pkpy_COutputHandler handler) {
    VM* vm = (VM*)vm_handle;
    vm->_stdout = handler;
}

void pkpy_set_import_handler(pkpy_vm* vm_handle, pkpy_CImportHandler handler) {
    VM* vm = (VM*)vm_handle;
    vm->_import_handler = handler;
}

void* pkpy_new_repl(pkpy_vm* vm_handle) { return new REPL((VM*)vm_handle); }

bool pkpy_repl_input(void* r, const char* line) { return ((REPL*)r)->input(line); }

void pkpy_delete_repl(void* repl) { delete (REPL*)repl; }

#endif  // PK_NO_EXPORT_C_API

}  // namespace pkpy