/*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2013, 2014 Damien P. George
   * Copyright (c) 2014 Paul Sokolovsky
   *
   * 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 <stdio.h>
  #include <string.h>
  
  #include "py/objstr.h"
  #include "py/objstringio.h"
  #include "py/runtime.h"
  #include "py/stream.h"
  
  #if MICROPY_PY_IO
  
  #if MICROPY_CPYTHON_COMPAT
  STATIC void check_stringio_is_open(const mp_obj_stringio_t *o) {
      if (o->vstr == NULL) {
          mp_raise_ValueError("I/O operation on closed file");
      }
  }
  #else
  #define check_stringio_is_open(o)
  #endif
  
  STATIC void stringio_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
      (void)kind;
      mp_obj_stringio_t *self = MP_OBJ_TO_PTR(self_in);
      mp_printf(print, self->base.type == &mp_type_stringio ? "<io.StringIO 0x%x>" : "<io.BytesIO 0x%x>", self);
  }
  
  STATIC mp_uint_t stringio_read(mp_obj_t o_in, void *buf, mp_uint_t size, int *errcode) {
      (void)errcode;
      mp_obj_stringio_t *o = MP_OBJ_TO_PTR(o_in);
      check_stringio_is_open(o);
      if (o->vstr->len <= o->pos) {  // read to EOF, or seeked to EOF or beyond
          return 0;
      }
      mp_uint_t remaining = o->vstr->len - o->pos;
      if (size > remaining) {
          size = remaining;
      }
      memcpy(buf, o->vstr->buf + o->pos, size);
      o->pos += size;
      return size;
  }
  
  STATIC void stringio_copy_on_write(mp_obj_stringio_t *o) {
      const void *buf = o->vstr->buf;
      o->vstr->buf = m_new(char, o->vstr->len);
      memcpy(o->vstr->buf, buf, o->vstr->len);
      o->vstr->fixed_buf = false;
      o->ref_obj = MP_OBJ_NULL;
  }
  
  STATIC mp_uint_t stringio_write(mp_obj_t o_in, const void *buf, mp_uint_t size, int *errcode) {
      (void)errcode;
      mp_obj_stringio_t *o = MP_OBJ_TO_PTR(o_in);
      check_stringio_is_open(o);
  
      if (o->vstr->fixed_buf) {
          stringio_copy_on_write(o);
      }
  
      mp_uint_t new_pos = o->pos + size;
      if (new_pos < size) {
          // Writing <size> bytes will overflow o->pos beyond limit of mp_uint_t.
          *errcode = MP_EFBIG;
          return MP_STREAM_ERROR;
      }
      mp_uint_t org_len = o->vstr->len;
      if (new_pos > o->vstr->alloc) {
          // Take all what's already allocated...
          o->vstr->len = o->vstr->alloc;
          // ... and add more
          vstr_add_len(o->vstr, new_pos - o->vstr->alloc);
      }
      // If there was a seek past EOF, clear the hole
      if (o->pos > org_len) {
          memset(o->vstr->buf + org_len, 0, o->pos - org_len);
      }
      memcpy(o->vstr->buf + o->pos, buf, size);
      o->pos = new_pos;
      if (new_pos > o->vstr->len) {
          o->vstr->len = new_pos;
      }
      return size;
  }
  
  STATIC mp_uint_t stringio_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_t arg, int *errcode) {
      (void)errcode;
      mp_obj_stringio_t *o = MP_OBJ_TO_PTR(o_in);
      switch (request) {
          case MP_STREAM_SEEK: {
              struct mp_stream_seek_t *s = (struct mp_stream_seek_t*)arg;
              mp_uint_t ref = 0;
              switch (s->whence) {
                  case MP_SEEK_CUR:
                      ref = o->pos;
                      break;
                  case MP_SEEK_END:
                      ref = o->vstr->len;
                      break;
              }
              mp_uint_t new_pos = ref + s->offset;
  
              // For MP_SEEK_SET, offset is unsigned
              if (s->whence != MP_SEEK_SET && s->offset < 0) {
                  if (new_pos > ref) {
                      // Negative offset from SEEK_CUR or SEEK_END went past 0.
                      // CPython sets position to 0, POSIX returns an EINVAL error
                      new_pos = 0;
                  }
              } else if (new_pos < ref) {
                  // positive offset went beyond the limit of mp_uint_t
                  *errcode = MP_EINVAL;  // replace with MP_EOVERFLOW when defined
                  return MP_STREAM_ERROR;
              }
              s->offset = o->pos = new_pos;
              return 0;
          }
          case MP_STREAM_FLUSH:
              return 0;
          case MP_STREAM_CLOSE:
              #if MICROPY_CPYTHON_COMPAT
              vstr_free(o->vstr);
              o->vstr = NULL;
              #else
              vstr_clear(o->vstr);
              o->vstr->alloc = 0;
              o->vstr->len = 0;
              o->pos = 0;
              #endif
              return 0;
          default:
              *errcode = MP_EINVAL;
              return MP_STREAM_ERROR;
      }
  }
  
  #define STREAM_TO_CONTENT_TYPE(o) (((o)->base.type == &mp_type_stringio) ? &mp_type_str : &mp_type_bytes)
  
  STATIC mp_obj_t stringio_getvalue(mp_obj_t self_in) {
      mp_obj_stringio_t *self = MP_OBJ_TO_PTR(self_in);
      check_stringio_is_open(self);
      // TODO: Try to avoid copying string
      return mp_obj_new_str_of_type(STREAM_TO_CONTENT_TYPE(self), (byte*)self->vstr->buf, self->vstr->len);
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_1(stringio_getvalue_obj, stringio_getvalue);
  
  STATIC mp_obj_t stringio___exit__(size_t n_args, const mp_obj_t *args) {
      (void)n_args;
      return mp_stream_close(args[0]);
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(stringio___exit___obj, 4, 4, stringio___exit__);
  
  STATIC mp_obj_stringio_t *stringio_new(const mp_obj_type_t *type) {
      mp_obj_stringio_t *o = m_new_obj(mp_obj_stringio_t);
      o->base.type = type;
      o->pos = 0;
      o->ref_obj = MP_OBJ_NULL;
      return o;
  }
  
  STATIC mp_obj_t stringio_make_new(const mp_obj_type_t *type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
      (void)n_kw; // TODO check n_kw==0
  
      mp_uint_t sz = 16;
      bool initdata = false;
      mp_buffer_info_t bufinfo;
  
      mp_obj_stringio_t *o = stringio_new(type_in);
  
      if (n_args > 0) {
          if (MP_OBJ_IS_INT(args[0])) {
              sz = mp_obj_get_int(args[0]);
          } else {
              mp_get_buffer_raise(args[0], &bufinfo, MP_BUFFER_READ);
  
              if (MP_OBJ_IS_STR_OR_BYTES(args[0])) {
                  o->vstr = m_new_obj(vstr_t);
                  vstr_init_fixed_buf(o->vstr, bufinfo.len, bufinfo.buf);
                  o->vstr->len = bufinfo.len;
                  o->ref_obj = args[0];
                  return MP_OBJ_FROM_PTR(o);
              }
  
              sz = bufinfo.len;
              initdata = true;
          }
      }
  
      o->vstr = vstr_new(sz);
  
      if (initdata) {
          stringio_write(MP_OBJ_FROM_PTR(o), bufinfo.buf, bufinfo.len, NULL);
          // Cur ptr is always at the beginning of buffer at the construction
          o->pos = 0;
      }
      return MP_OBJ_FROM_PTR(o);
  }
  
  STATIC const mp_rom_map_elem_t stringio_locals_dict_table[] = {
      { MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_stream_read_obj) },
      { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) },
      { MP_ROM_QSTR(MP_QSTR_readline), MP_ROM_PTR(&mp_stream_unbuffered_readline_obj) },
      { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) },
      { MP_ROM_QSTR(MP_QSTR_seek), MP_ROM_PTR(&mp_stream_seek_obj) },
      { MP_ROM_QSTR(MP_QSTR_flush), MP_ROM_PTR(&mp_stream_flush_obj) },
      { MP_ROM_QSTR(MP_QSTR_close), MP_ROM_PTR(&mp_stream_close_obj) },
      { MP_ROM_QSTR(MP_QSTR_getvalue), MP_ROM_PTR(&stringio_getvalue_obj) },
      { MP_ROM_QSTR(MP_QSTR___enter__), MP_ROM_PTR(&mp_identity_obj) },
      { MP_ROM_QSTR(MP_QSTR___exit__), MP_ROM_PTR(&stringio___exit___obj) },
  };
  
  STATIC MP_DEFINE_CONST_DICT(stringio_locals_dict, stringio_locals_dict_table);
  
  STATIC const mp_stream_p_t stringio_stream_p = {
      .read = stringio_read,
      .write = stringio_write,
      .ioctl = stringio_ioctl,
      .is_text = true,
  };
  
  STATIC const mp_stream_p_t bytesio_stream_p = {
      .read = stringio_read,
      .write = stringio_write,
      .ioctl = stringio_ioctl,
  };
  
  const mp_obj_type_t mp_type_stringio = {
      { &mp_type_type },
      .name = MP_QSTR_StringIO,
      .print = stringio_print,
      .make_new = stringio_make_new,
      .getiter = mp_identity_getiter,
      .iternext = mp_stream_unbuffered_iter,
      .protocol = &stringio_stream_p,
      .locals_dict = (mp_obj_dict_t*)&stringio_locals_dict,
  };
  
  #if MICROPY_PY_IO_BYTESIO
  const mp_obj_type_t mp_type_bytesio = {
      { &mp_type_type },
      .name = MP_QSTR_BytesIO,
      .print = stringio_print,
      .make_new = stringio_make_new,
      .getiter = mp_identity_getiter,
      .iternext = mp_stream_unbuffered_iter,
      .protocol = &bytesio_stream_p,
      .locals_dict = (mp_obj_dict_t*)&stringio_locals_dict,
  };
  #endif
  
  #endif