/*
 * Copyright (c) 2009-2021, Google LLC
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of Google LLC nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL Google LLC BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "upb/text_encode.h"

#include <ctype.h>
#include <float.h>
#include <inttypes.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>

#include "upb/reflection.h"

// Must be last.
#include "upb/port_def.inc"

typedef struct {
  char *buf, *ptr, *end;
  size_t overflow;
  int indent_depth;
  int options;
  const upb_DefPool* ext_pool;
  _upb_mapsorter sorter;
} txtenc;

static void txtenc_msg(txtenc* e, const upb_Message* msg,
                       const upb_MessageDef* m);

static void txtenc_putbytes(txtenc* e, const void* data, size_t len) {
  size_t have = e->end - e->ptr;
  if (UPB_LIKELY(have >= len)) {
    memcpy(e->ptr, data, len);
    e->ptr += len;
  } else {
    if (have) {
      memcpy(e->ptr, data, have);
      e->ptr += have;
    }
    e->overflow += (len - have);
  }
}

static void txtenc_putstr(txtenc* e, const char* str) {
  txtenc_putbytes(e, str, strlen(str));
}

static void txtenc_printf(txtenc* e, const char* fmt, ...) {
  size_t n;
  size_t have = e->end - e->ptr;
  va_list args;

  va_start(args, fmt);
  n = vsnprintf(e->ptr, have, fmt, args);
  va_end(args);

  if (UPB_LIKELY(have > n)) {
    e->ptr += n;
  } else {
    e->ptr = UPB_PTRADD(e->ptr, have);
    e->overflow += (n - have);
  }
}

static void txtenc_indent(txtenc* e) {
  if ((e->options & UPB_TXTENC_SINGLELINE) == 0) {
    int i = e->indent_depth;
    while (i-- > 0) {
      txtenc_putstr(e, "  ");
    }
  }
}

static void txtenc_endfield(txtenc* e) {
  if (e->options & UPB_TXTENC_SINGLELINE) {
    txtenc_putstr(e, " ");
  } else {
    txtenc_putstr(e, "\n");
  }
}

static void txtenc_enum(int32_t val, const upb_FieldDef* f, txtenc* e) {
  const upb_EnumDef* e_def = upb_FieldDef_EnumSubDef(f);
  const upb_EnumValueDef* ev = upb_EnumDef_FindValueByNumber(e_def, val);

  if (ev) {
    txtenc_printf(e, "%s", upb_EnumValueDef_Name(ev));
  } else {
    txtenc_printf(e, "%" PRId32, val);
  }
}

static void txtenc_string(txtenc* e, upb_StringView str, bool bytes) {
  const char* ptr = str.data;
  const char* end = ptr + str.size;
  txtenc_putstr(e, "\"");

  while (ptr < end) {
    switch (*ptr) {
      case '\n':
        txtenc_putstr(e, "\\n");
        break;
      case '\r':
        txtenc_putstr(e, "\\r");
        break;
      case '\t':
        txtenc_putstr(e, "\\t");
        break;
      case '\"':
        txtenc_putstr(e, "\\\"");
        break;
      case '\'':
        txtenc_putstr(e, "\\'");
        break;
      case '\\':
        txtenc_putstr(e, "\\\\");
        break;
      default:
        if ((bytes || (uint8_t)*ptr < 0x80) && !isprint(*ptr)) {
          txtenc_printf(e, "\\%03o", (int)(uint8_t)*ptr);
        } else {
          txtenc_putbytes(e, ptr, 1);
        }
        break;
    }
    ptr++;
  }

  txtenc_putstr(e, "\"");
}

static void txtenc_field(txtenc* e, upb_MessageValue val,
                         const upb_FieldDef* f) {
  txtenc_indent(e);
  upb_CType type = upb_FieldDef_CType(f);
  const char* name = upb_FieldDef_Name(f);

  if (type == kUpb_CType_Message) {
    txtenc_printf(e, "%s {", name);
    txtenc_endfield(e);
    e->indent_depth++;
    txtenc_msg(e, val.msg_val, upb_FieldDef_MessageSubDef(f));
    e->indent_depth--;
    txtenc_indent(e);
    txtenc_putstr(e, "}");
    txtenc_endfield(e);
    return;
  }

  txtenc_printf(e, "%s: ", name);

  switch (type) {
    case kUpb_CType_Bool:
      txtenc_putstr(e, val.bool_val ? "true" : "false");
      break;
    case kUpb_CType_Float:
      txtenc_printf(e, "%f", val.float_val);
      break;
    case kUpb_CType_Double:
      txtenc_printf(e, "%f", val.double_val);
      break;
    case kUpb_CType_Int32:
      txtenc_printf(e, "%" PRId32, val.int32_val);
      break;
    case kUpb_CType_UInt32:
      txtenc_printf(e, "%" PRIu32, val.uint32_val);
      break;
    case kUpb_CType_Int64:
      txtenc_printf(e, "%" PRId64, val.int64_val);
      break;
    case kUpb_CType_UInt64:
      txtenc_printf(e, "%" PRIu64, val.uint64_val);
      break;
    case kUpb_CType_String:
      txtenc_string(e, val.str_val, false);
      break;
    case kUpb_CType_Bytes:
      txtenc_string(e, val.str_val, true);
      break;
    case kUpb_CType_Enum:
      txtenc_enum(val.int32_val, f, e);
      break;
    default:
      UPB_UNREACHABLE();
  }

  txtenc_endfield(e);
}

/*
 * Arrays print as simple repeated elements, eg.
 *
 *    foo_field: 1
 *    foo_field: 2
 *    foo_field: 3
 */
static void txtenc_array(txtenc* e, const upb_Array* arr,
                         const upb_FieldDef* f) {
  size_t i;
  size_t size = upb_Array_Size(arr);

  for (i = 0; i < size; i++) {
    txtenc_field(e, upb_Array_Get(arr, i), f);
  }
}

static void txtenc_mapentry(txtenc* e, upb_MessageValue key,
                            upb_MessageValue val, const upb_FieldDef* f) {
  const upb_MessageDef* entry = upb_FieldDef_MessageSubDef(f);
  const upb_FieldDef* key_f = upb_MessageDef_Field(entry, 0);
  const upb_FieldDef* val_f = upb_MessageDef_Field(entry, 1);
  txtenc_indent(e);
  txtenc_printf(e, "%s {", upb_FieldDef_Name(f));
  txtenc_endfield(e);
  e->indent_depth++;

  txtenc_field(e, key, key_f);
  txtenc_field(e, val, val_f);

  e->indent_depth--;
  txtenc_indent(e);
  txtenc_putstr(e, "}");
  txtenc_endfield(e);
}

/*
 * Maps print as messages of key/value, etc.
 *
 *    foo_map: {
 *      key: "abc"
 *      value: 123
 *    }
 *    foo_map: {
 *      key: "def"
 *      value: 456
 *    }
 */
static void txtenc_map(txtenc* e, const upb_Map* map, const upb_FieldDef* f) {
  if (e->options & UPB_TXTENC_NOSORT) {
    size_t iter = kUpb_Map_Begin;
    while (upb_MapIterator_Next(map, &iter)) {
      upb_MessageValue key = upb_MapIterator_Key(map, iter);
      upb_MessageValue val = upb_MapIterator_Value(map, iter);
      txtenc_mapentry(e, key, val, f);
    }
  } else {
    const upb_MessageDef* entry = upb_FieldDef_MessageSubDef(f);
    const upb_FieldDef* key_f = upb_MessageDef_Field(entry, 0);
    _upb_sortedmap sorted;
    upb_MapEntry ent;

    _upb_mapsorter_pushmap(&e->sorter, upb_FieldDef_Type(key_f), map, &sorted);
    while (_upb_sortedmap_next(&e->sorter, map, &sorted, &ent)) {
      upb_MessageValue key, val;
      memcpy(&key, &ent.k, sizeof(key));
      memcpy(&val, &ent.v, sizeof(val));
      txtenc_mapentry(e, key, val, f);
    }
    _upb_mapsorter_popmap(&e->sorter, &sorted);
  }
}

#define CHK(x)      \
  do {              \
    if (!(x)) {     \
      return false; \
    }               \
  } while (0)

static const char* txtenc_parsevarint(const char* ptr, const char* limit,
                                      uint64_t* val) {
  uint8_t byte;
  int bitpos = 0;
  *val = 0;

  do {
    CHK(bitpos < 70 && ptr < limit);
    byte = *ptr;
    *val |= (uint64_t)(byte & 0x7F) << bitpos;
    ptr++;
    bitpos += 7;
  } while (byte & 0x80);

  return ptr;
}

/*
 * Unknown fields are printed by number.
 *
 * 1001: 123
 * 1002: "hello"
 * 1006: 0xdeadbeef
 * 1003: {
 *   1: 111
 * }
 */
static const char* txtenc_unknown(txtenc* e, const char* ptr, const char* end,
                                  int groupnum) {
  while (ptr < end) {
    uint64_t tag_64;
    uint32_t tag;
    CHK(ptr = txtenc_parsevarint(ptr, end, &tag_64));
    CHK(tag_64 < UINT32_MAX);
    tag = (uint32_t)tag_64;

    if ((tag & 7) == kUpb_WireType_EndGroup) {
      CHK((tag >> 3) == (uint32_t)groupnum);
      return ptr;
    }

    txtenc_indent(e);
    txtenc_printf(e, "%d: ", (int)(tag >> 3));

    switch (tag & 7) {
      case kUpb_WireType_Varint: {
        uint64_t val;
        CHK(ptr = txtenc_parsevarint(ptr, end, &val));
        txtenc_printf(e, "%" PRIu64, val);
        break;
      }
      case kUpb_WireType_32Bit: {
        uint32_t val;
        CHK(end - ptr >= 4);
        memcpy(&val, ptr, 4);
        ptr += 4;
        txtenc_printf(e, "0x%08" PRIu32, val);
        break;
      }
      case kUpb_WireType_64Bit: {
        uint64_t val;
        CHK(end - ptr >= 8);
        memcpy(&val, ptr, 8);
        ptr += 8;
        txtenc_printf(e, "0x%016" PRIu64, val);
        break;
      }
      case kUpb_WireType_Delimited: {
        uint64_t len;
        size_t avail = end - ptr;
        char* start = e->ptr;
        size_t start_overflow = e->overflow;
        CHK(ptr = txtenc_parsevarint(ptr, end, &len));
        CHK(avail >= len);

        /* Speculatively try to parse as message. */
        txtenc_putstr(e, "{");
        txtenc_endfield(e);
        e->indent_depth++;
        if (txtenc_unknown(e, ptr, end, -1)) {
          e->indent_depth--;
          txtenc_indent(e);
          txtenc_putstr(e, "}");
        } else {
          /* Didn't work out, print as raw bytes. */
          upb_StringView str;
          e->indent_depth--;
          e->ptr = start;
          e->overflow = start_overflow;
          str.data = ptr;
          str.size = len;
          txtenc_string(e, str, true);
        }
        ptr += len;
        break;
      }
      case kUpb_WireType_StartGroup:
        txtenc_putstr(e, "{");
        txtenc_endfield(e);
        e->indent_depth++;
        CHK(ptr = txtenc_unknown(e, ptr, end, tag >> 3));
        e->indent_depth--;
        txtenc_indent(e);
        txtenc_putstr(e, "}");
        break;
    }
    txtenc_endfield(e);
  }

  return groupnum == -1 ? ptr : NULL;
}

#undef CHK

static void txtenc_msg(txtenc* e, const upb_Message* msg,
                       const upb_MessageDef* m) {
  size_t iter = kUpb_Message_Begin;
  const upb_FieldDef* f;
  upb_MessageValue val;

  while (upb_Message_Next(msg, m, e->ext_pool, &f, &val, &iter)) {
    if (upb_FieldDef_IsMap(f)) {
      txtenc_map(e, val.map_val, f);
    } else if (upb_FieldDef_IsRepeated(f)) {
      txtenc_array(e, val.array_val, f);
    } else {
      txtenc_field(e, val, f);
    }
  }

  if ((e->options & UPB_TXTENC_SKIPUNKNOWN) == 0) {
    size_t len;
    const char* ptr = upb_Message_GetUnknown(msg, &len);
    char* start = e->ptr;
    if (ptr) {
      if (!txtenc_unknown(e, ptr, ptr + len, -1)) {
        /* Unknown failed to parse, back up and don't print it at all. */
        e->ptr = start;
      }
    }
  }
}

size_t txtenc_nullz(txtenc* e, size_t size) {
  size_t ret = e->ptr - e->buf + e->overflow;

  if (size > 0) {
    if (e->ptr == e->end) e->ptr--;
    *e->ptr = '\0';
  }

  return ret;
}

size_t upb_text_encode(const upb_Message* msg, const upb_MessageDef* m,
                       const upb_DefPool* ext_pool, int options, char* buf,
                       size_t size) {
  txtenc e;

  e.buf = buf;
  e.ptr = buf;
  e.end = UPB_PTRADD(buf, size);
  e.overflow = 0;
  e.indent_depth = 0;
  e.options = options;
  e.ext_pool = ext_pool;
  _upb_mapsorter_init(&e.sorter);

  txtenc_msg(&e, msg, m);
  _upb_mapsorter_destroy(&e.sorter);
  return txtenc_nullz(&e, size);
}