/*
   * 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 <stdio.h>
  #include <string.h>
  #include <assert.h>
  
  #include "py/parsenum.h"
  #include "py/runtime.h"
  
  #if MICROPY_PY_BUILTINS_FLOAT
  
  #include <math.h>
  #include "py/formatfloat.h"
  
  #if MICROPY_OBJ_REPR != MICROPY_OBJ_REPR_C && MICROPY_OBJ_REPR != MICROPY_OBJ_REPR_D
  
  // M_E and M_PI are not part of the math.h standard and may not be defined
  #ifndef M_E
  #define M_E (2.7182818284590452354)
  #endif
  #ifndef M_PI
  #define M_PI (3.14159265358979323846)
  #endif
  
  typedef struct _mp_obj_float_t {
      mp_obj_base_t base;
      mp_float_t value;
  } mp_obj_float_t;
  
  const mp_obj_float_t mp_const_float_e_obj = {{&mp_type_float}, M_E};
  const mp_obj_float_t mp_const_float_pi_obj = {{&mp_type_float}, M_PI};
  
  #endif
  
  #if MICROPY_FLOAT_HIGH_QUALITY_HASH
  // must return actual integer value if it fits in mp_int_t
  mp_int_t mp_float_hash(mp_float_t src) {
  #if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE
  typedef uint64_t mp_float_uint_t;
  #elif MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
  typedef uint32_t mp_float_uint_t;
  #endif
      union {
          mp_float_t f;
          #if MP_ENDIANNESS_LITTLE
          struct { mp_float_uint_t frc:MP_FLOAT_FRAC_BITS, exp:MP_FLOAT_EXP_BITS, sgn:1; } p;
          #else
          struct { mp_float_uint_t sgn:1, exp:MP_FLOAT_EXP_BITS, frc:MP_FLOAT_FRAC_BITS; } p;
          #endif
          mp_float_uint_t i;
      } u = {.f = src};
  
      mp_int_t val;
      const int adj_exp = (int)u.p.exp - MP_FLOAT_EXP_BIAS;
      if (adj_exp < 0) {
          // value < 1; must be sure to handle 0.0 correctly (ie return 0)
          val = u.i;
      } else {
          // if adj_exp is max then: u.p.frc==0 indicates inf, else NaN
          // else: 1 <= value
          mp_float_uint_t frc = u.p.frc | ((mp_float_uint_t)1 << MP_FLOAT_FRAC_BITS);
  
          if (adj_exp <= MP_FLOAT_FRAC_BITS) {
              // number may have a fraction; xor the integer part with the fractional part
              val = (frc >> (MP_FLOAT_FRAC_BITS - adj_exp))
                  ^ (frc & ((1 << (MP_FLOAT_FRAC_BITS - adj_exp)) - 1));
          } else if ((unsigned int)adj_exp < BITS_PER_BYTE * sizeof(mp_int_t) - 1) {
              // the number is a (big) whole integer and will fit in val's signed-width
              val = (mp_int_t)frc << (adj_exp - MP_FLOAT_FRAC_BITS);
          } else {
              // integer part will overflow val's width so just use what bits we can
              val = frc;
          }
      }
  
      if (u.p.sgn) {
          val = -val;
      }
  
      return val;
  }
  #endif
  
  STATIC void float_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
      (void)kind;
      mp_float_t o_val = mp_obj_float_get(o_in);
  #if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
      char buf[16];
      #if MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_C
      const int precision = 6;
      #else
      const int precision = 7;
      #endif
  #else
      char buf[32];
      const int precision = 16;
  #endif
      mp_format_float(o_val, buf, sizeof(buf), 'g', precision, '\0');
      mp_print_str(print, buf);
      if (strchr(buf, '.') == NULL && strchr(buf, 'e') == NULL && strchr(buf, 'n') == NULL) {
          // Python floats always have decimal point (unless inf or nan)
          mp_print_str(print, ".0");
      }
  }
  
  STATIC mp_obj_t float_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, 1, false);
  
      switch (n_args) {
          case 0:
              return mp_obj_new_float(0);
  
          case 1:
          default: {
              mp_buffer_info_t bufinfo;
              if (mp_get_buffer(args[0], &bufinfo, MP_BUFFER_READ)) {
                  // a textual representation, parse it
                  return mp_parse_num_decimal(bufinfo.buf, bufinfo.len, false, false, NULL);
              } else if (mp_obj_is_float(args[0])) {
                  // a float, just return it
                  return args[0];
              } else {
                  // something else, try to cast it to a float
                  return mp_obj_new_float(mp_obj_get_float(args[0]));
              }
          }
      }
  }
  
  STATIC mp_obj_t float_unary_op(mp_unary_op_t op, mp_obj_t o_in) {
      mp_float_t val = mp_obj_float_get(o_in);
      switch (op) {
          case MP_UNARY_OP_BOOL: return mp_obj_new_bool(val != 0);
          case MP_UNARY_OP_HASH: return MP_OBJ_NEW_SMALL_INT(mp_float_hash(val));
          case MP_UNARY_OP_POSITIVE: return o_in;
          case MP_UNARY_OP_NEGATIVE: return mp_obj_new_float(-val);
          case MP_UNARY_OP_ABS: {
              // TODO check for NaN etc
              if (val < 0) {
                  return mp_obj_new_float(-val);
              } else {
                  return o_in;
              }
          }
          default: return MP_OBJ_NULL; // op not supported
      }
  }
  
  STATIC mp_obj_t float_binary_op(mp_binary_op_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
      mp_float_t lhs_val = mp_obj_float_get(lhs_in);
  #if MICROPY_PY_BUILTINS_COMPLEX
      if (MP_OBJ_IS_TYPE(rhs_in, &mp_type_complex)) {
          return mp_obj_complex_binary_op(op, lhs_val, 0, rhs_in);
      } else
  #endif
      {
          return mp_obj_float_binary_op(op, lhs_val, rhs_in);
      }
  }
  
  const mp_obj_type_t mp_type_float = {
      { &mp_type_type },
      .name = MP_QSTR_float,
      .print = float_print,
      .make_new = float_make_new,
      .unary_op = float_unary_op,
      .binary_op = float_binary_op,
  };
  
  #if MICROPY_OBJ_REPR != MICROPY_OBJ_REPR_C && MICROPY_OBJ_REPR != MICROPY_OBJ_REPR_D
  
  mp_obj_t mp_obj_new_float(mp_float_t value) {
      mp_obj_float_t *o = m_new(mp_obj_float_t, 1);
      o->base.type = &mp_type_float;
      o->value = value;
      return MP_OBJ_FROM_PTR(o);
  }
  
  mp_float_t mp_obj_float_get(mp_obj_t self_in) {
      assert(mp_obj_is_float(self_in));
      mp_obj_float_t *self = MP_OBJ_TO_PTR(self_in);
      return self->value;
  }
  
  #endif
  
  STATIC void mp_obj_float_divmod(mp_float_t *x, mp_float_t *y) {
      // logic here follows that of CPython
      // https://docs.python.org/3/reference/expressions.html#binary-arithmetic-operations
      // x == (x//y)*y + (x%y)
      // divmod(x, y) == (x//y, x%y)
      mp_float_t mod = MICROPY_FLOAT_C_FUN(fmod)(*x, *y);
      mp_float_t div = (*x - mod) / *y;
  
      // Python specs require that mod has same sign as second operand
      if (mod == 0.0) {
          mod = MICROPY_FLOAT_C_FUN(copysign)(0.0, *y);
      } else {
          if ((mod < 0.0) != (*y < 0.0)) {
              mod += *y;
              div -= 1.0;
          }
      }
  
      mp_float_t floordiv;
      if (div == 0.0) {
          // if division is zero, take the correct sign of zero
          floordiv = MICROPY_FLOAT_C_FUN(copysign)(0.0, *x / *y);
      } else {
          // Python specs require that x == (x//y)*y + (x%y)
          floordiv = MICROPY_FLOAT_C_FUN(floor)(div);
          if (div - floordiv > 0.5) {
              floordiv += 1.0;
          }
      }
  
      // return results
      *x = floordiv;
      *y = mod;
  }
  
  mp_obj_t mp_obj_float_binary_op(mp_binary_op_t op, mp_float_t lhs_val, mp_obj_t rhs_in) {
      mp_float_t rhs_val;
      if (!mp_obj_get_float_maybe(rhs_in, &rhs_val)) {
          return MP_OBJ_NULL; // op not supported
      }
  
      switch (op) {
          case MP_BINARY_OP_ADD:
          case MP_BINARY_OP_INPLACE_ADD: lhs_val += rhs_val; break;
          case MP_BINARY_OP_SUBTRACT:
          case MP_BINARY_OP_INPLACE_SUBTRACT: lhs_val -= rhs_val; break;
          case MP_BINARY_OP_MULTIPLY:
          case MP_BINARY_OP_INPLACE_MULTIPLY: lhs_val *= rhs_val; break;
          case MP_BINARY_OP_FLOOR_DIVIDE:
          case MP_BINARY_OP_INPLACE_FLOOR_DIVIDE:
              if (rhs_val == 0) {
                  zero_division_error:
                  mp_raise_msg(&mp_type_ZeroDivisionError, "division by zero");
              }
              // Python specs require that x == (x//y)*y + (x%y) so we must
              // call divmod to compute the correct floor division, which
              // returns the floor divide in lhs_val.
              mp_obj_float_divmod(&lhs_val, &rhs_val);
              break;
          case MP_BINARY_OP_TRUE_DIVIDE:
          case MP_BINARY_OP_INPLACE_TRUE_DIVIDE:
              if (rhs_val == 0) {
                  goto zero_division_error;
              }
              lhs_val /= rhs_val;
              break;
          case MP_BINARY_OP_MODULO:
          case MP_BINARY_OP_INPLACE_MODULO:
              if (rhs_val == 0) {
                  goto zero_division_error;
              }
              lhs_val = MICROPY_FLOAT_C_FUN(fmod)(lhs_val, rhs_val);
              // Python specs require that mod has same sign as second operand
              if (lhs_val == 0.0) {
                  lhs_val = MICROPY_FLOAT_C_FUN(copysign)(0.0, rhs_val);
              } else {
                  if ((lhs_val < 0.0) != (rhs_val < 0.0)) {
                      lhs_val += rhs_val;
                  }
              }
              break;
          case MP_BINARY_OP_POWER:
          case MP_BINARY_OP_INPLACE_POWER:
              if (lhs_val == 0 && rhs_val < 0 && !isinf(rhs_val)) {
                  goto zero_division_error;
              }
              if (lhs_val < 0 && rhs_val != MICROPY_FLOAT_C_FUN(floor)(rhs_val)) {
                  #if MICROPY_PY_BUILTINS_COMPLEX
                  return mp_obj_complex_binary_op(MP_BINARY_OP_POWER, lhs_val, 0, rhs_in);
                  #else
                  mp_raise_ValueError("complex values not supported");
                  #endif
              }
              lhs_val = MICROPY_FLOAT_C_FUN(pow)(lhs_val, rhs_val);
              break;
          case MP_BINARY_OP_DIVMOD: {
              if (rhs_val == 0) {
                  goto zero_division_error;
              }
              mp_obj_float_divmod(&lhs_val, &rhs_val);
              mp_obj_t tuple[2] = {
                  mp_obj_new_float(lhs_val),
                  mp_obj_new_float(rhs_val),
              };
              return mp_obj_new_tuple(2, tuple);
          }
          case MP_BINARY_OP_LESS: return mp_obj_new_bool(lhs_val < rhs_val);
          case MP_BINARY_OP_MORE: return mp_obj_new_bool(lhs_val > rhs_val);
          case MP_BINARY_OP_EQUAL: return mp_obj_new_bool(lhs_val == rhs_val);
          case MP_BINARY_OP_LESS_EQUAL: return mp_obj_new_bool(lhs_val <= rhs_val);
          case MP_BINARY_OP_MORE_EQUAL: return mp_obj_new_bool(lhs_val >= rhs_val);
  
          default:
              return MP_OBJ_NULL; // op not supported
      }
      return mp_obj_new_float(lhs_val);
  }
  
  #endif // MICROPY_PY_BUILTINS_FLOAT