#pragma once

#include <stdint.h>
#include <stdbool.h>
#include <stdarg.h>

/************* Public Types *************/
typedef struct py_TValue py_TValue;
typedef uint16_t py_Name;
typedef int16_t py_Type;

typedef int64_t py_i64;
typedef double py_f64;

/// Generic reference.
typedef py_TValue* py_Ref;
/// An object reference which has the same lifespan as the object.
typedef py_TValue* py_ObjectRef;
/// A global reference which has the same lifespan as the VM.
typedef py_TValue* py_GlobalRef;
/// A specific location in the stack.
typedef py_TValue* py_StackRef;
/// A temporary reference which has a short or unknown lifespan.
typedef py_TValue* py_TmpRef;

/// Native function signature.
/// @param argc number of arguments.
/// @param argv array of arguments. Use `py_arg(i)` macro to get the i-th argument.
/// @return true if the function is successful.
typedef bool (*py_CFunction)(int argc, py_StackRef argv);

typedef enum BindType {
    BindType_FUNCTION,
    BindType_STATICMETHOD,
    BindType_CLASSMETHOD,
} BindType;

/************* Global VMs *************/
void py_initialize();
void py_finalize();

/// Run a simple source string. Do not change the stack.
bool py_exec(const char* source);
/// Eval a simple expression.
/// The result will be set to `py_retval()`.
bool py_eval(const char* source);

/************* Values Creation *************/
void py_newint(py_Ref, py_i64);
void py_newfloat(py_Ref, py_f64);
void py_newbool(py_Ref, bool);
void py_newstr(py_Ref, const char*);
void py_newstrn(py_Ref, const char*, int);
// void py_newfstr(py_Ref, const char*, ...);
unsigned char* py_newbytes(py_Ref, int);
void py_newnone(py_Ref);
void py_newnotimplemented(py_Ref out);
void py_newellipsis(py_Ref out);
void py_newnull(py_Ref);

/// Create a tuple with n UNINITIALIZED elements.
/// You should initialize all elements before using it.
void py_newtuple(py_Ref, int n);
/// Create a list.
void py_newlist(py_Ref);
/// Create a list with n UNINITIALIZED elements.
/// You should initialize all elements before using it.
void py_newlistn(py_Ref, int n);

py_Name py_name(const char*);
const char* py_name2str(py_Name);
bool py_ismagicname(py_Name);

// opaque types
void py_newdict(py_Ref);
void py_newset(py_Ref);
void py_newslice(py_Ref, const py_Ref start, const py_Ref stop, const py_Ref step);

// new style decl-based function
void py_newfunction(py_Ref out, py_CFunction, const char* sig);
void py_newfunction2(py_Ref out,
                     py_CFunction,
                     const char* sig,
                     BindType bt,
                     const char* docstring,
                     const py_Ref upvalue);
// old style argc-based function
void py_newnativefunc(py_Ref out, py_CFunction);

/// Create a new object.
/// @param out output reference.
/// @param type type of the object.
/// @param slots number of slots. Use -1 to create a `__dict__`.
/// @param udsize size of your userdata. You can use `py_touserdata()` to get the pointer to it.
void py_newobject(py_Ref out, py_Type type, int slots, int udsize);
/************* Type Cast *************/
py_i64 py_toint(const py_Ref);
py_f64 py_tofloat(const py_Ref);
bool py_castfloat(const py_Ref, py_f64* out);
bool py_tobool(const py_Ref);
py_Type py_totype(const py_Ref);
const char* py_tostr(const py_Ref);
const char* py_tostrn(const py_Ref, int* size);
unsigned char* py_tobytes(const py_Ref, int* size);

void* py_touserdata(const py_Ref);

#define py_isint(self) py_istype(self, tp_int)
#define py_isfloat(self) py_istype(self, tp_float)
#define py_isbool(self) py_istype(self, tp_bool)
#define py_isstr(self) py_istype(self, tp_str)

bool py_istype(const py_Ref, py_Type);
bool py_isinstance(const py_Ref obj, py_Type type);
bool py_issubclass(py_Type derived, py_Type base);

/************* References *************/
#define py_offset(p, i) (py_Ref)((char*)p + ((i) << 4))

#define TypeError(x) false
#define py_arg(i) py_offset(argv, i)
#define py_checkargc(n)                                                                            \
    if(argc != n) return TypeError()

py_GlobalRef py_tpmagic(py_Type type, py_Name name);
#define py_bindmagic(type, __magic__, f) py_newnativefunc(py_tpmagic((type), __magic__), (f))

// new style decl-based bindings
py_TmpRef py_bind(py_Ref obj, const char* sig, py_CFunction f);
py_TmpRef py_bind2(py_Ref obj,
                const char* sig,
                py_CFunction f,
                BindType bt,
                const char* docstring,
                const py_Ref upvalue);
// old style argc-based bindings
void py_bindmethod(py_Type type, const char* name, py_CFunction f);
void py_bindmethod2(py_Type type, const char* name, py_CFunction f, BindType bt);
void py_bindnativefunc(py_Ref obj, const char* name, py_CFunction f);

/// Get the reference to the i-th register.
/// All registers are located in a contiguous memory.
py_GlobalRef py_reg(int i);

/// Get the reference of the object's `__dict__`.
/// The object must have a `__dict__`.
/// Returns a reference to the value or NULL if not found.
py_ObjectRef py_getdict(const py_Ref self, py_Name name);
void py_setdict(py_Ref self, py_Name name, const py_Ref val);

/// Get the reference of the i-th slot of the object.
/// The object must have slots and `i` must be in range.
py_ObjectRef py_getslot(const py_Ref self, int i);
void py_setslot(py_Ref self, int i, const py_Ref val);

py_TmpRef py_getupvalue(py_StackRef argv);
void py_setupvalue(py_StackRef argv, const py_Ref val);

/// Gets the attribute of the object.
bool py_getattr(const py_Ref self, py_Name name, py_Ref out);
/// Gets the unbound method of the object.
bool py_getunboundmethod(const py_Ref self,
                         py_Name name,
                         bool fallback,
                         py_Ref out,
                         py_Ref out_self);
/// Sets the attribute of the object.
bool py_setattr(py_Ref self, py_Name name, const py_Ref val);
/// Deletes the attribute of the object.
bool py_delattr(py_Ref self, py_Name name);

bool py_getitem(const py_Ref self, const py_Ref key, py_Ref out);
bool py_setitem(py_Ref self, const py_Ref key, const py_Ref val);
bool py_delitem(py_Ref self, const py_Ref key);

/// Perform a binary operation on the stack.
/// It assumes `lhs` and `rhs` are already pushed to the stack.
/// The result will be set to `py_retval()`.
bool py_binaryop(const py_Ref lhs, const py_Ref rhs, py_Name op, py_Name rop);

#define py_binaryadd(lhs, rhs) py_binaryop(lhs, rhs, __add__, __radd__)
#define py_binarysub(lhs, rhs) py_binaryop(lhs, rhs, __sub__, __rsub__)
#define py_binarymul(lhs, rhs) py_binaryop(lhs, rhs, __mul__, __rmul__)
#define py_binarytruediv(lhs, rhs) py_binaryop(lhs, rhs, __truediv__, __rtruediv__)
#define py_binaryfloordiv(lhs, rhs) py_binaryop(lhs, rhs, __floordiv__, __rfloordiv__)
#define py_binarymod(lhs, rhs) py_binaryop(lhs, rhs, __mod__, __rmod__)
#define py_binarypow(lhs, rhs) py_binaryop(lhs, rhs, __pow__, __rpow__)

#define py_binarylshift(lhs, rhs) py_binaryop(lhs, rhs, __lshift__, 0)
#define py_binaryrshift(lhs, rhs) py_binaryop(lhs, rhs, __rshift__, 0)
#define py_binaryand(lhs, rhs) py_binaryop(lhs, rhs, __and__, 0)
#define py_binaryor(lhs, rhs) py_binaryop(lhs, rhs, __or__, 0)
#define py_binaryxor(lhs, rhs) py_binaryop(lhs, rhs, __xor__, 0)
#define py_binarymatmul(lhs, rhs) py_binaryop(lhs, rhs, __matmul__, 0)

/// Equivalent to `*dst = *src`.
void py_assign(py_Ref dst, const py_Ref src);

/************* Stack Operations *************/
/// Returns a reference to the i-th object from the top of the stack.
/// i should be negative, e.g. (-1) means TOS.
py_StackRef py_peek(int i);
/// Pushes the object to the stack.
void py_push(const py_Ref src);
/// Pops an object from the stack.
void py_pop();
/// Shrink the stack by n.
void py_shrink(int n);
/// Get a temporary variable from the stack and returns the reference to it.
py_StackRef py_pushtmp();
/// Free n temporary variable.
#define py_poptmp(n) py_shrink(n)

#define py_gettop() py_peek(-1)
#define py_getsecond() py_peek(-2)
#define py_settop(v) py_assign(py_peek(-1), v)
#define py_setsecond(v) py_assign(py_peek(-2), v)
#define py_duptop() py_push(py_peek(-1))
#define py_dupsecond() py_push(py_peek(-2))
/************* Modules *************/
py_TmpRef py_newmodule(const char* name, const char* package);
py_TmpRef py_getmodule(const char* name);

/// Import a module.
/// The result will be set to `py_retval()`.
bool py_import(const char* name);

/************* Errors *************/
/// Print the last error to the console.
void py_printexc();
/// Format the last error to a string.
void py_formatexc(char* out);

/************* Operators *************/
/// Equivalent to `bool(val)`.
/// Returns 1 if `val` is truthy, otherwise 0.
/// Returns -1 if an error occurred.
int py_bool(const py_Ref val);

int py_eq(const py_Ref, const py_Ref);
int py_ne(const py_Ref, const py_Ref);
int py_le(const py_Ref, const py_Ref);
int py_lt(const py_Ref, const py_Ref);
int py_ge(const py_Ref, const py_Ref);
int py_gt(const py_Ref, const py_Ref);

bool py_hash(const py_Ref, py_i64* out);

/// Python equivalent to `lhs is rhs`.
bool py_isidentical(const py_Ref, const py_Ref);

/// A stack operation that calls a function.
/// It assumes `argc + kwargc` arguments are already pushed to the stack.
/// The result will be set to `py_retval()`.
/// The stack size will be reduced by `argc + kwargc`.
bool pk_vectorcall(int argc, int kwargc, bool op_call);
/// Call a function.
/// It prepares the stack and then performs a `vectorcall(argc, 0, false)`.
/// The result will be set to `py_retval()`.
/// The stack remains unchanged after the operation.
bool py_call(py_Ref f, int argc, py_Ref argv);
/// Call a non-magic method.
/// It prepares the stack and then performs a `vectorcall(argc+1, 0, false)`.
/// The result will be set to `py_retval()`.
/// The stack remains unchanged after the operation.
bool py_callmethod(py_Ref self, py_Name, int argc, py_Ref argv);
/// Call a magic method using a continuous buffer.
/// The result will be set to `py_retval()`.
/// The stack remains unchanged after the operation.
bool py_callmagic(py_Name name, int argc, py_Ref argv);

#define py_repr(self) py_callmagic(__repr__, 1, self)
#define py_str(self) py_callmagic(__str__, 1, self)

/// The return value of the most recent call.
py_GlobalRef py_retval();

#define py_isnull(self) ((self)->type == 0)

/* tuple */

// unchecked functions, if self is not a tuple, the behavior is undefined
py_ObjectRef py_tuple__getitem(const py_Ref self, int i);
void py_tuple__setitem(py_Ref self, int i, const py_Ref val);
int py_tuple__len(const py_Ref self);

// unchecked functions, if self is not a list, the behavior is undefined
py_ObjectRef py_list__getitem(const py_Ref self, int i);
void py_list__setitem(py_Ref self, int i, const py_Ref val);
void py_list__delitem(py_Ref self, int i);
int py_list__len(const py_Ref self);
void py_list__append(py_Ref self, const py_Ref val);
void py_list__clear(py_Ref self);
void py_list__insert(py_Ref self, int i, const py_Ref val);

// internal functions
typedef struct pk_TypeInfo pk_TypeInfo;
pk_TypeInfo* pk_tpinfo(const py_Ref self);

/// Search the magic method from the given type to the base type.
/// Return the reference or NULL if not found.
py_GlobalRef py_tpfindmagic(py_Type, py_Name name);

/// Get the type object of the given type.
py_GlobalRef py_tpobject(py_Type type);

/// Get the type name.
const char* py_tpname(py_Type type);

/// Check if the object is an instance of the given type.
/// Re
bool py_checktype(const py_Ref self, py_Type type);

/// Python favored string formatting.
/// %d: int
/// %i: py_i64 (int64_t)
/// %f: py_f64 (double)
/// %s: const char*
/// %q: c11_sv
/// %v: c11_sv
/// %c: char
/// %p: void*
/// %t: py_Type
/// %n: py_Name


enum py_MagicNames{
    py_MagicNames__NULL,  // 0 is reserved
    #define MAGIC_METHOD(x) x,
    #include "pocketpy/xmacros/magics.h"
    #undef MAGIC_METHOD
};

enum py_PredefinedTypes{
    tp_object = 1, tp_type,
    tp_int, tp_float, tp_bool, tp_str,
    tp_list, tp_tuple,
    tp_slice, tp_range, tp_module,
    tp_function, tp_nativefunc, tp_bound_method,
    tp_super, tp_exception, tp_bytes, tp_mappingproxy,
    tp_dict, tp_property, tp_star_wrapper,
    tp_staticmethod, tp_classmethod,
    tp_none_type, tp_not_implemented_type,
    tp_ellipsis,
    tp_syntax_error, tp_stop_iteration
};

#ifdef __cplusplus
}
#endif