/*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2013, 2014 Damien P. George
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  
  #include <stdlib.h>
  #include <assert.h>
  #include <string.h>
  
  #include "py/parsenum.h"
  #include "py/smallint.h"
  #include "py/objint.h"
  #include "py/objstr.h"
  #include "py/runtime.h"
  #include "py/binary.h"
  
  #if MICROPY_PY_BUILTINS_FLOAT
  #include <math.h>
  #endif
  
  // This dispatcher function is expected to be independent of the implementation of long int
  STATIC mp_obj_t mp_obj_int_make_new(const mp_obj_type_t *type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
      (void)type_in;
      mp_arg_check_num(n_args, n_kw, 0, 2, false);
  
      switch (n_args) {
          case 0:
              return MP_OBJ_NEW_SMALL_INT(0);
  
          case 1:
              if (MP_OBJ_IS_INT(args[0])) {
                  // already an int (small or long), just return it
                  return args[0];
              } else if (MP_OBJ_IS_STR_OR_BYTES(args[0])) {
                  // a string, parse it
                  size_t l;
                  const char *s = mp_obj_str_get_data(args[0], &l);
                  return mp_parse_num_integer(s, l, 0, NULL);
  #if MICROPY_PY_BUILTINS_FLOAT
              } else if (mp_obj_is_float(args[0])) {
                  return mp_obj_new_int_from_float(mp_obj_float_get(args[0]));
  #endif
              } else {
                  // try to convert to small int (eg from bool)
                  return MP_OBJ_NEW_SMALL_INT(mp_obj_get_int(args[0]));
              }
  
          case 2:
          default: {
              // should be a string, parse it
              // TODO proper error checking of argument types
              size_t l;
              const char *s = mp_obj_str_get_data(args[0], &l);
              return mp_parse_num_integer(s, l, mp_obj_get_int(args[1]), NULL);
          }
      }
  }
  
  #if MICROPY_PY_BUILTINS_FLOAT
  
  typedef enum {
      MP_FP_CLASS_FIT_SMALLINT,
      MP_FP_CLASS_FIT_LONGINT,
      MP_FP_CLASS_OVERFLOW
  } mp_fp_as_int_class_t;
  
  STATIC mp_fp_as_int_class_t mp_classify_fp_as_int(mp_float_t val) {
      union {
          mp_float_t f;
  #if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
          uint32_t i;
  #elif MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE
          uint32_t i[2];
  #endif
      } u = {val};
  
      uint32_t e;
  #if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
      e = u.i;
  #elif MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE
      e = u.i[MP_ENDIANNESS_LITTLE];
  #endif
  #define MP_FLOAT_SIGN_SHIFT_I32 ((MP_FLOAT_FRAC_BITS + MP_FLOAT_EXP_BITS) % 32)
  #define MP_FLOAT_EXP_SHIFT_I32 (MP_FLOAT_FRAC_BITS % 32)
  
      if (e & (1U << MP_FLOAT_SIGN_SHIFT_I32)) {
  #if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE
          e |= u.i[MP_ENDIANNESS_BIG] != 0;
  #endif
          if ((e & ~(1 << MP_FLOAT_SIGN_SHIFT_I32)) == 0) {
              // handle case of -0 (when sign is set but rest of bits are zero)
              e = 0;
          } else {
              e += ((1 << MP_FLOAT_EXP_BITS) - 1) << MP_FLOAT_EXP_SHIFT_I32;
          }
      } else {
          e &= ~((1 << MP_FLOAT_EXP_SHIFT_I32) - 1);
      }
      // 8 * sizeof(uintptr_t) counts the number of bits for a small int
      // TODO provide a way to configure this properly
      if (e <= ((8 * sizeof(uintptr_t) + MP_FLOAT_EXP_BIAS - 3) << MP_FLOAT_EXP_SHIFT_I32)) {
          return MP_FP_CLASS_FIT_SMALLINT;
      }
  #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_LONGLONG
      if (e <= (((sizeof(long long) * BITS_PER_BYTE) + MP_FLOAT_EXP_BIAS - 2) << MP_FLOAT_EXP_SHIFT_I32)) {
          return MP_FP_CLASS_FIT_LONGINT;
      }
  #endif
  #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_MPZ
      return MP_FP_CLASS_FIT_LONGINT;
  #else
      return MP_FP_CLASS_OVERFLOW;
  #endif
  }
  #undef MP_FLOAT_SIGN_SHIFT_I32
  #undef MP_FLOAT_EXP_SHIFT_I32
  
  mp_obj_t mp_obj_new_int_from_float(mp_float_t val) {
      int cl = fpclassify(val);
      if (cl == FP_INFINITE) {
          nlr_raise(mp_obj_new_exception_msg(&mp_type_OverflowError, "can't convert inf to int"));
      } else if (cl == FP_NAN) {
          mp_raise_ValueError("can't convert NaN to int");
      } else {
          mp_fp_as_int_class_t icl = mp_classify_fp_as_int(val);
          if (icl == MP_FP_CLASS_FIT_SMALLINT) {
              return MP_OBJ_NEW_SMALL_INT((mp_int_t)val);
          #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_MPZ
          } else {
              mp_obj_int_t *o = mp_obj_int_new_mpz();
              mpz_set_from_float(&o->mpz, val);
              return MP_OBJ_FROM_PTR(o);
          }
          #else
          #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_LONGLONG
          } else if (icl == MP_FP_CLASS_FIT_LONGINT) {
              return mp_obj_new_int_from_ll((long long)val);
          #endif
          } else {
              mp_raise_ValueError("float too big");
          }
          #endif
      }
  }
  
  #endif
  
  #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_LONGLONG
  typedef mp_longint_impl_t fmt_int_t;
  typedef unsigned long long fmt_uint_t;
  #else
  typedef mp_int_t fmt_int_t;
  typedef mp_uint_t fmt_uint_t;
  #endif
  
  void mp_obj_int_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
      (void)kind;
      // The size of this buffer is rather arbitrary. If it's not large
      // enough, a dynamic one will be allocated.
      char stack_buf[sizeof(fmt_int_t) * 4];
      char *buf = stack_buf;
      size_t buf_size = sizeof(stack_buf);
      size_t fmt_size;
  
      char *str = mp_obj_int_formatted(&buf, &buf_size, &fmt_size, self_in, 10, NULL, '\0', '\0');
      mp_print_str(print, str);
  
      if (buf != stack_buf) {
          m_del(char, buf, buf_size);
      }
  }
  
  STATIC const uint8_t log_base2_floor[] = {
      0, 1, 1, 2,
      2, 2, 2, 3,
      3, 3, 3, 3,
      3, 3, 3, 4,
      /* if needed, these are the values for higher bases
      4, 4, 4, 4,
      4, 4, 4, 4,
      4, 4, 4, 4,
      4, 4, 4, 5
      */
  };
  
  size_t mp_int_format_size(size_t num_bits, int base, const char *prefix, char comma) {
      assert(2 <= base && base <= 16);
      size_t num_digits = num_bits / log_base2_floor[base - 1] + 1;
      size_t num_commas = comma ? num_digits / 3 : 0;
      size_t prefix_len = prefix ? strlen(prefix) : 0;
      return num_digits + num_commas + prefix_len + 2; // +1 for sign, +1 for null byte
  }
  
  // This routine expects you to pass in a buffer and size (in *buf and *buf_size).
  // If, for some reason, this buffer is too small, then it will allocate a
  // buffer and return the allocated buffer and size in *buf and *buf_size. It
  // is the callers responsibility to free this allocated buffer.
  //
  // The resulting formatted string will be returned from this function and the
  // formatted size will be in *fmt_size.
  char *mp_obj_int_formatted(char **buf, size_t *buf_size, size_t *fmt_size, mp_const_obj_t self_in,
                             int base, const char *prefix, char base_char, char comma) {
      fmt_int_t num;
      #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_NONE
      // Only have small ints; get the integer value to format.
      num = MP_OBJ_SMALL_INT_VALUE(self_in);
      #else
      if (MP_OBJ_IS_SMALL_INT(self_in)) {
          // A small int; get the integer value to format.
          num = MP_OBJ_SMALL_INT_VALUE(self_in);
      } else {
          assert(MP_OBJ_IS_TYPE(self_in, &mp_type_int));
          // Not a small int.
          #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_LONGLONG
          const mp_obj_int_t *self = self_in;
          // Get the value to format; mp_obj_get_int truncates to mp_int_t.
          num = self->val;
          #else
          // Delegate to the implementation for the long int.
          return mp_obj_int_formatted_impl(buf, buf_size, fmt_size, self_in, base, prefix, base_char, comma);
          #endif
      }
      #endif
  
      char sign = '\0';
      if (num < 0) {
          num = -num;
          sign = '-';
      }
  
      size_t needed_size = mp_int_format_size(sizeof(fmt_int_t) * 8, base, prefix, comma);
      if (needed_size > *buf_size) {
          *buf = m_new(char, needed_size);
          *buf_size = needed_size;
      }
      char *str = *buf;
  
      char *b = str + needed_size;
      *(--b) = '\0';
      char *last_comma = b;
  
      if (num == 0) {
          *(--b) = '0';
      } else {
          do {
              // The cast to fmt_uint_t is because num is positive and we want unsigned arithmetic
              int c = (fmt_uint_t)num % base;
              num = (fmt_uint_t)num / base;
              if (c >= 10) {
                  c += base_char - 10;
              } else {
                  c += '0';
              }
              *(--b) = c;
              if (comma && num != 0 && b > str && (last_comma - b) == 3) {
                  *(--b) = comma;
                  last_comma = b;
              }
          }
          while (b > str && num != 0);
      }
      if (prefix) {
          size_t prefix_len = strlen(prefix);
          char *p = b - prefix_len;
          if (p > str) {
              b = p;
              while (*prefix) {
                  *p++ = *prefix++;
              }
          }
      }
      if (sign && b > str) {
          *(--b) = sign;
      }
      *fmt_size = *buf + needed_size - b - 1;
  
      return b;
  }
  
  #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_NONE
  
  int mp_obj_int_sign(mp_obj_t self_in) {
      mp_int_t val = mp_obj_get_int(self_in);
      if (val < 0) {
          return -1;
      } else if (val > 0) {
          return 1;
      } else {
          return 0;
      }
  }
  
  // This is called for operations on SMALL_INT that are not handled by mp_unary_op
  mp_obj_t mp_obj_int_unary_op(mp_unary_op_t op, mp_obj_t o_in) {
      return MP_OBJ_NULL; // op not supported
  }
  
  // This is called for operations on SMALL_INT that are not handled by mp_binary_op
  mp_obj_t mp_obj_int_binary_op(mp_binary_op_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
      return mp_obj_int_binary_op_extra_cases(op, lhs_in, rhs_in);
  }
  
  // This is called only with strings whose value doesn't fit in SMALL_INT
  mp_obj_t mp_obj_new_int_from_str_len(const char **str, size_t len, bool neg, unsigned int base) {
      mp_raise_msg(&mp_type_OverflowError, "long int not supported in this build");
      return mp_const_none;
  }
  
  // This is called when an integer larger than a SMALL_INT is needed (although val might still fit in a SMALL_INT)
  mp_obj_t mp_obj_new_int_from_ll(long long val) {
      mp_raise_msg(&mp_type_OverflowError, "small int overflow");
      return mp_const_none;
  }
  
  // This is called when an integer larger than a SMALL_INT is needed (although val might still fit in a SMALL_INT)
  mp_obj_t mp_obj_new_int_from_ull(unsigned long long val) {
      mp_raise_msg(&mp_type_OverflowError, "small int overflow");
      return mp_const_none;
  }
  
  mp_obj_t mp_obj_new_int_from_uint(mp_uint_t value) {
      // SMALL_INT accepts only signed numbers, so make sure the input
      // value fits completely in the small-int positive range.
      if ((value & ~MP_SMALL_INT_POSITIVE_MASK) == 0) {
          return MP_OBJ_NEW_SMALL_INT(value);
      }
      mp_raise_msg(&mp_type_OverflowError, "small int overflow");
      return mp_const_none;
  }
  
  mp_obj_t mp_obj_new_int(mp_int_t value) {
      if (MP_SMALL_INT_FITS(value)) {
          return MP_OBJ_NEW_SMALL_INT(value);
      }
      mp_raise_msg(&mp_type_OverflowError, "small int overflow");
      return mp_const_none;
  }
  
  mp_int_t mp_obj_int_get_truncated(mp_const_obj_t self_in) {
      return MP_OBJ_SMALL_INT_VALUE(self_in);
  }
  
  mp_int_t mp_obj_int_get_checked(mp_const_obj_t self_in) {
      return MP_OBJ_SMALL_INT_VALUE(self_in);
  }
  
  #endif // MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_NONE
  
  // This dispatcher function is expected to be independent of the implementation of long int
  // It handles the extra cases for integer-like arithmetic
  mp_obj_t mp_obj_int_binary_op_extra_cases(mp_binary_op_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
      if (rhs_in == mp_const_false) {
          // false acts as 0
          return mp_binary_op(op, lhs_in, MP_OBJ_NEW_SMALL_INT(0));
      } else if (rhs_in == mp_const_true) {
          // true acts as 0
          return mp_binary_op(op, lhs_in, MP_OBJ_NEW_SMALL_INT(1));
      } else if (op == MP_BINARY_OP_MULTIPLY) {
          if (MP_OBJ_IS_STR_OR_BYTES(rhs_in) || MP_OBJ_IS_TYPE(rhs_in, &mp_type_tuple) || MP_OBJ_IS_TYPE(rhs_in, &mp_type_list)) {
              // multiply is commutative for these types, so delegate to them
              return mp_binary_op(op, rhs_in, lhs_in);
          }
      }
      return MP_OBJ_NULL; // op not supported
  }
  
  // this is a classmethod
  STATIC mp_obj_t int_from_bytes(size_t n_args, const mp_obj_t *args) {
      // TODO: Support signed param (assumes signed=False at the moment)
      (void)n_args;
  
      // get the buffer info
      mp_buffer_info_t bufinfo;
      mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_READ);
  
      const byte* buf = (const byte*)bufinfo.buf;
      int delta = 1;
      if (args[2] == MP_OBJ_NEW_QSTR(MP_QSTR_little)) {
          buf += bufinfo.len - 1;
          delta = -1;
      }
  
      mp_uint_t value = 0;
      size_t len = bufinfo.len;
      for (; len--; buf += delta) {
          #if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
          if (value > (MP_SMALL_INT_MAX >> 8)) {
              // Result will overflow a small-int so construct a big-int
              return mp_obj_int_from_bytes_impl(args[2] != MP_OBJ_NEW_QSTR(MP_QSTR_little), bufinfo.len, bufinfo.buf);
          }
          #endif
          value = (value << 8) | *buf;
      }
      return mp_obj_new_int_from_uint(value);
  }
  
  STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(int_from_bytes_fun_obj, 3, 4, int_from_bytes);
  STATIC MP_DEFINE_CONST_CLASSMETHOD_OBJ(int_from_bytes_obj, MP_ROM_PTR(&int_from_bytes_fun_obj));
  
  STATIC mp_obj_t int_to_bytes(size_t n_args, const mp_obj_t *args) {
      // TODO: Support signed param (assumes signed=False)
      (void)n_args;
  
      mp_int_t len = mp_obj_get_int(args[1]);
      if (len < 0) {
          mp_raise_ValueError(NULL);
      }
      bool big_endian = args[2] != MP_OBJ_NEW_QSTR(MP_QSTR_little);
  
      vstr_t vstr;
      vstr_init_len(&vstr, len);
      byte *data = (byte*)vstr.buf;
      memset(data, 0, len);
  
      #if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
      if (!MP_OBJ_IS_SMALL_INT(args[0])) {
          mp_obj_int_to_bytes_impl(args[0], big_endian, len, data);
      } else
      #endif
      {
          mp_int_t val = MP_OBJ_SMALL_INT_VALUE(args[0]);
          size_t l = MIN((size_t)len, sizeof(val));
          mp_binary_set_int(l, big_endian, data + (big_endian ? (len - l) : 0), val);
      }
  
      return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(int_to_bytes_obj, 3, 4, int_to_bytes);
  
  STATIC const mp_rom_map_elem_t int_locals_dict_table[] = {
      { MP_ROM_QSTR(MP_QSTR_from_bytes), MP_ROM_PTR(&int_from_bytes_obj) },
      { MP_ROM_QSTR(MP_QSTR_to_bytes), MP_ROM_PTR(&int_to_bytes_obj) },
  };
  
  STATIC MP_DEFINE_CONST_DICT(int_locals_dict, int_locals_dict_table);
  
  const mp_obj_type_t mp_type_int = {
      { &mp_type_type },
      .name = MP_QSTR_int,
      .print = mp_obj_int_print,
      .make_new = mp_obj_int_make_new,
      .unary_op = mp_obj_int_unary_op,
      .binary_op = mp_obj_int_binary_op,
      .locals_dict = (mp_obj_dict_t*)&int_locals_dict,
  };