// After editing this file, run "go generate" in the ../data directory.

// Copyright 2020 The Wuffs Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// ---------------- Auxiliary - JSON

#if !defined(WUFFS_CONFIG__MODULES) || defined(WUFFS_CONFIG__MODULE__AUX__JSON)

#include <utility>

namespace wuffs_aux {

DecodeJsonResult::DecodeJsonResult(std::string&& error_message0,
                                   uint64_t cursor_position0)
    : error_message(std::move(error_message0)),
      cursor_position(cursor_position0) {}

std::string  //
DecodeJsonCallbacks::AppendByteString(std::string&& val) {
  return "wuffs_aux::JsonDecoder: unexpected JSON byte string";
}

void  //
DecodeJsonCallbacks::Done(DecodeJsonResult& result,
                          sync_io::Input& input,
                          IOBuffer& buffer) {}

DecodeJsonResult  //
DecodeJson(DecodeJsonCallbacks&& callbacks,
           sync_io::Input&& input,
           wuffs_base__slice_u32 quirks) {
  // Prepare the wuffs_base__io_buffer and the resultant error_message.
  wuffs_base__io_buffer* io_buf = input.BringsItsOwnIOBuffer();
  wuffs_base__io_buffer fallback_io_buf = wuffs_base__empty_io_buffer();
  std::unique_ptr<uint8_t[]> fallback_io_array(nullptr);
  if (!io_buf) {
    fallback_io_array = std::unique_ptr<uint8_t[]>(new uint8_t[4096]);
    fallback_io_buf = wuffs_base__ptr_u8__writer(fallback_io_array.get(), 4096);
    io_buf = &fallback_io_buf;
  }
  size_t cursor_index = 0;
  std::string ret_error_message;
  std::string io_error_message;

  do {
    // Prepare the low-level JSON decoder.
    wuffs_json__decoder::unique_ptr dec = wuffs_json__decoder::alloc();
    if (!dec) {
      ret_error_message = "wuffs_aux::JsonDecoder: out of memory";
      goto done;
    }
    for (size_t i = 0; i < quirks.len; i++) {
      dec->set_quirk_enabled(quirks.ptr[i], true);
    }

    // Prepare the wuffs_base__tok_buffer.
    wuffs_base__token tok_array[256];
    wuffs_base__token_buffer tok_buf =
        wuffs_base__slice_token__writer(wuffs_base__make_slice_token(
            &tok_array[0], (sizeof(tok_array) / sizeof(tok_array[0]))));
    wuffs_base__status tok_status = wuffs_base__make_status(nullptr);

    // Prepare other state.
    uint32_t depth = 0;
    std::string str;

    // Loop, doing these two things:
    //  1. Get the next token.
    //  2. Process that token.
    while (true) {
      // 1. Get the next token.

      while (tok_buf.meta.ri >= tok_buf.meta.wi) {
        if (tok_status.repr == nullptr) {
          // No-op.
        } else if (tok_status.repr == wuffs_base__suspension__short_write) {
          tok_buf.compact();
        } else if (tok_status.repr == wuffs_base__suspension__short_read) {
          // Read from input to io_buf.
          if (!io_error_message.empty()) {
            ret_error_message = std::move(io_error_message);
            goto done;
          } else if (cursor_index != io_buf->meta.ri) {
            ret_error_message =
                "wuffs_aux::JsonDecoder: internal error: bad cursor_index";
            goto done;
          } else if (io_buf->meta.closed) {
            ret_error_message =
                "wuffs_aux::JsonDecoder: internal error: io_buf is closed";
            goto done;
          }
          io_buf->compact();
          if (io_buf->meta.wi >= io_buf->data.len) {
            ret_error_message =
                "wuffs_aux::JsonDecoder: internal error: io_buf is full";
            goto done;
          }
          cursor_index = io_buf->meta.ri;
          io_error_message = input.CopyIn(io_buf);
        } else {
          ret_error_message = tok_status.message();
          goto done;
        }

        if (WUFFS_JSON__DECODER_WORKBUF_LEN_MAX_INCL_WORST_CASE != 0) {
          ret_error_message =
              "wuffs_aux::JsonDecoder: internal error: bad WORKBUF_LEN";
          goto done;
        }
        wuffs_base__slice_u8 work_buf = wuffs_base__empty_slice_u8();
        tok_status = dec->decode_tokens(&tok_buf, io_buf, work_buf);
      }

      wuffs_base__token token = tok_buf.data.ptr[tok_buf.meta.ri++];
      uint64_t token_len = token.length();
      if ((io_buf->meta.ri < cursor_index) ||
          ((io_buf->meta.ri - cursor_index) < token_len)) {
        ret_error_message =
            "wuffs_aux::JsonDecoder: internal error: bad token indexes";
        goto done;
      }
      uint8_t* token_ptr = io_buf->data.ptr + cursor_index;
      cursor_index += token_len;

      // 2. Process that token.

      int64_t vbc = token.value_base_category();
      uint64_t vbd = token.value_base_detail();
      switch (vbc) {
        case WUFFS_BASE__TOKEN__VBC__FILLER:
          continue;

        case WUFFS_BASE__TOKEN__VBC__STRUCTURE: {
          if (vbd & WUFFS_BASE__TOKEN__VBD__STRUCTURE__PUSH) {
            ret_error_message = callbacks.Push(static_cast<uint32_t>(vbd));
            if (!ret_error_message.empty()) {
              goto done;
            }
            depth++;
            continue;
          }
          ret_error_message = callbacks.Pop(static_cast<uint32_t>(vbd));
          depth--;
          goto parsed_a_value;
        }

        case WUFFS_BASE__TOKEN__VBC__STRING: {
          if (vbd & WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_0_DST_1_SRC_DROP) {
            // No-op.
          } else if (vbd &
                     WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_1_DST_1_SRC_COPY) {
            const char* ptr =  // Convert from (uint8_t*).
                static_cast<const char*>(static_cast<void*>(token_ptr));
            str.append(ptr, token_len);
          } else if (
              vbd &
              WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_1_DST_4_SRC_BACKSLASH_X) {
            wuffs_base__slice_u8 encoded =
                wuffs_base__make_slice_u8(token_ptr, token_len);
            while (encoded.len > 0) {
              uint8_t decoded[64];
              constexpr bool src_closed = true;
              wuffs_base__transform__output o = wuffs_base__base_16__decode4(
                  wuffs_base__make_slice_u8(&decoded[0], sizeof decoded),
                  encoded, src_closed, WUFFS_BASE__BASE_16__DEFAULT_OPTIONS);
              if (o.status.is_error()) {
                ret_error_message = o.status.message();
                goto done;
              } else if ((o.num_dst > (sizeof decoded)) ||
                         (o.num_src > encoded.len)) {
                ret_error_message =
                    "wuffs_aux::JsonDecoder: internal error: inconsistent "
                    "base16 decoding";
                goto done;
              }
              str.append(  // Convert from (uint8_t*).
                  static_cast<const char*>(static_cast<void*>(&decoded[0])),
                  o.num_dst);
              encoded.ptr += o.num_src;
              encoded.len -= o.num_src;
            }
          } else {
            goto fail;
          }
          if (token.continued()) {
            continue;
          }
          ret_error_message =
              (vbd & WUFFS_BASE__TOKEN__VBD__STRING__CHAIN_MUST_BE_UTF_8)
                  ? callbacks.AppendTextString(std::move(str))
                  : callbacks.AppendByteString(std::move(str));
          str.clear();
          goto parsed_a_value;
        }

        case WUFFS_BASE__TOKEN__VBC__UNICODE_CODE_POINT: {
          uint8_t u[WUFFS_BASE__UTF_8__BYTE_LENGTH__MAX_INCL];
          size_t n = wuffs_base__utf_8__encode(
              wuffs_base__make_slice_u8(
                  &u[0], WUFFS_BASE__UTF_8__BYTE_LENGTH__MAX_INCL),
              static_cast<uint32_t>(vbd));
          const char* ptr =  // Convert from (uint8_t*).
              static_cast<const char*>(static_cast<void*>(&u[0]));
          str.append(ptr, n);
          if (token.continued()) {
            continue;
          }
          goto fail;
        }

        case WUFFS_BASE__TOKEN__VBC__LITERAL: {
          ret_error_message =
              (vbd & WUFFS_BASE__TOKEN__VBD__LITERAL__NULL)
                  ? callbacks.AppendNull()
                  : callbacks.AppendBool(vbd &
                                         WUFFS_BASE__TOKEN__VBD__LITERAL__TRUE);
          goto parsed_a_value;
        }

        case WUFFS_BASE__TOKEN__VBC__NUMBER: {
          if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__FORMAT_TEXT) {
            if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_INTEGER_SIGNED) {
              wuffs_base__result_i64 r = wuffs_base__parse_number_i64(
                  wuffs_base__make_slice_u8(token_ptr, token_len),
                  WUFFS_BASE__PARSE_NUMBER_XXX__DEFAULT_OPTIONS);
              if (r.status.is_ok()) {
                ret_error_message = callbacks.AppendI64(r.value);
                goto parsed_a_value;
              }
            }
            if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_FLOATING_POINT) {
              wuffs_base__result_f64 r = wuffs_base__parse_number_f64(
                  wuffs_base__make_slice_u8(token_ptr, token_len),
                  WUFFS_BASE__PARSE_NUMBER_XXX__DEFAULT_OPTIONS);
              if (r.status.is_ok()) {
                ret_error_message = callbacks.AppendF64(r.value);
                goto parsed_a_value;
              }
            }
          } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_NEG_INF) {
            ret_error_message = callbacks.AppendF64(
                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(
                    0xFFF0000000000000ul));
            goto parsed_a_value;
          } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_POS_INF) {
            ret_error_message = callbacks.AppendF64(
                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(
                    0x7FF0000000000000ul));
            goto parsed_a_value;
          } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_NEG_NAN) {
            ret_error_message = callbacks.AppendF64(
                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(
                    0xFFFFFFFFFFFFFFFFul));
            goto parsed_a_value;
          } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_POS_NAN) {
            ret_error_message = callbacks.AppendF64(
                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(
                    0x7FFFFFFFFFFFFFFFul));
            goto parsed_a_value;
          }
          goto fail;
        }
      }

    fail:
      ret_error_message =
          "wuffs_aux::JsonDecoder: internal error: unexpected token";
      goto done;

    parsed_a_value:
      if (!ret_error_message.empty() || (depth == 0)) {
        goto done;
      }
    }
  } while (false);

done:
  DecodeJsonResult result(
      std::move(ret_error_message),
      wuffs_base__u64__sat_add(io_buf->meta.pos, cursor_index));
  callbacks.Done(result, input, *io_buf);
  return result;
}

}  // namespace wuffs_aux

#endif  // !defined(WUFFS_CONFIG__MODULES) ||
        // defined(WUFFS_CONFIG__MODULE__AUX__JSON)