/*
  Copyright 2011-2021 David Robillard <d@drobilla.net>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#include "read_utf8.h"
#include "reader.h"

#include "string_utils.h"

#include <stdio.h>

static SerdStatus
skip_invalid_utf8(SerdReader* const reader)
{
  for (int b = peek_byte(reader); b != EOF && ((uint8_t)b & 0x80);) {
    eat_byte_safe(reader, b);
    b = peek_byte(reader);
  }

  return reader->strict ? SERD_ERR_BAD_SYNTAX : SERD_FAILURE;
}

static SerdStatus
bad_char(SerdReader* const reader, const char* const fmt, const uint8_t c)
{
  r_err(reader, SERD_ERR_BAD_SYNTAX, fmt, c);
  return skip_invalid_utf8(reader);
}

static SerdStatus
read_utf8_continuation_bytes(SerdReader* const reader,
                             uint8_t           bytes[4],
                             uint32_t* const   size,
                             const uint8_t     lead)
{
  *size = utf8_num_bytes(lead);
  if (*size < 1 || *size > 4) {
    return bad_char(reader, "0x%X is not a UTF-8 leading byte", lead);
  }

  bytes[0] = lead;

  for (uint32_t i = 1u; i < *size; ++i) {
    const int b = peek_byte(reader);
    if (b == EOF) {
      return r_err(reader, SERD_ERR_NO_DATA, "unexpected end of input");
    }

    const uint8_t byte = (uint8_t)b;
    if (!(byte & 0x80u)) {
      return bad_char(reader, "0x%X is not a UTF-8 continuation byte", byte);
    }

    eat_byte_safe(reader, b);
    bytes[i] = byte;
  }

  return SERD_SUCCESS;
}

SerdStatus
read_utf8_continuation(SerdReader* const reader,
                       SerdNode* const   dest,
                       const uint8_t     lead)
{
  uint32_t size     = 0;
  uint8_t  bytes[4] = {0, 0, 0, 0};

  SerdStatus st = read_utf8_continuation_bytes(reader, bytes, &size, lead);
  if (st) {
    return reader->strict ? st : push_bytes(reader, dest, replacement_char, 3);
  }

  return push_bytes(reader, dest, bytes, size);
}

SerdStatus
read_utf8_code_point(SerdReader* const reader,
                     SerdNode* const   dest,
                     uint32_t* const   code,
                     const uint8_t     lead)
{
  uint32_t size     = 0u;
  uint8_t  bytes[4] = {lead, 0u, 0u, 0u};

  *code = 0u;

  eat_byte_safe(reader, lead);

  SerdStatus st = read_utf8_continuation_bytes(reader, bytes, &size, lead);
  if (st) {
    return reader->strict ? st : push_bytes(reader, dest, replacement_char, 3);
  }

  if (!(st = push_bytes(reader, dest, bytes, size))) {
    *code = parse_counted_utf8_char(bytes, size);
  }

  return st;
}