// Copyright 2011-2020 David Robillard <d@drobilla.net>
// SPDX-License-Identifier: ISC

#include "node.h"

#include "base64.h"
#include "string_utils.h"

#include "serd/serd.h"

#include <assert.h>
#include <float.h>
#include <math.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef _WIN32
#  ifndef isnan
#    define isnan(x) _isnan(x)
#  endif
#  ifndef isinf
#    define isinf(x) (!_finite(x))
#  endif
#endif

static size_t
serd_uri_string_length(const SerdURI* const uri)
{
  size_t len = uri->path_base.len;

#define ADD_LEN(field, n_delims)     \
  if ((field).len) {                 \
    len += (field).len + (n_delims); \
  }

  ADD_LEN(uri->path, 1)      // + possible leading `/'
  ADD_LEN(uri->scheme, 1)    // + trailing `:'
  ADD_LEN(uri->authority, 2) // + leading `//'
  ADD_LEN(uri->query, 1)     // + leading `?'
  ADD_LEN(uri->fragment, 1)  // + leading `#'

  return len + 2; // + 2 for authority `//'
}

static size_t
string_sink(const void* const buf, const size_t len, void* const stream)
{
  uint8_t** ptr = (uint8_t**)stream;
  memcpy(*ptr, buf, len);
  *ptr += len;
  return len;
}

SerdNode
serd_node_from_string(const SerdType type, const uint8_t* const str)
{
  if (!str) {
    return SERD_NODE_NULL;
  }

  SerdNodeFlags flags       = 0;
  size_t        buf_n_bytes = 0;
  const size_t  buf_n_chars = serd_strlen(str, &buf_n_bytes, &flags);
  SerdNode      ret         = {str, buf_n_bytes, buf_n_chars, flags, type};
  return ret;
}

SerdNode
serd_node_from_substring(const SerdType       type,
                         const uint8_t* const str,
                         const size_t         len)
{
  if (!str) {
    return SERD_NODE_NULL;
  }

  SerdNodeFlags flags       = 0;
  size_t        buf_n_bytes = 0;
  const size_t  buf_n_chars = serd_substrlen(str, len, &buf_n_bytes, &flags);
  assert(buf_n_bytes <= len);
  SerdNode ret = {str, buf_n_bytes, buf_n_chars, flags, type};
  return ret;
}

SerdNode
serd_node_copy(const SerdNode* const node)
{
  if (!node || !node->buf) {
    return SERD_NODE_NULL;
  }

  SerdNode copy = *node;
  uint8_t* buf  = (uint8_t*)malloc(copy.n_bytes + 1);
  memcpy(buf, node->buf, copy.n_bytes + 1);
  copy.buf = buf;
  return copy;
}

bool
serd_node_equals(const SerdNode* const a, const SerdNode* const b)
{
  return (a == b) ||
         (a->type == b->type && a->n_bytes == b->n_bytes &&
          a->n_chars == b->n_chars &&
          ((a->buf == b->buf) ||
           !memcmp((const char*)a->buf, (const char*)b->buf, a->n_bytes + 1)));
}

SerdNode
serd_node_new_uri_from_node(const SerdNode* const uri_node,
                            const SerdURI* const  base,
                            SerdURI* const        out)
{
  return (uri_node->type == SERD_URI && uri_node->buf)
           ? serd_node_new_uri_from_string(uri_node->buf, base, out)
           : SERD_NODE_NULL;
}

SerdNode
serd_node_new_uri_from_string(const uint8_t* const str,
                              const SerdURI* const base,
                              SerdURI* const       out)
{
  if (!str || str[0] == '\0') {
    // Empty URI => Base URI, or nothing if no base is given
    return base ? serd_node_new_uri(base, NULL, out) : SERD_NODE_NULL;
  }

  SerdURI uri;
  serd_uri_parse(str, &uri);
  return serd_node_new_uri(&uri, base, out); // Resolve/Serialise
}

static bool
is_uri_path_char(const uint8_t c)
{
  if (is_alpha(c) || is_digit(c)) {
    return true;
  }

  switch (c) {
  // unreserved:
  case '-':
  case '.':
  case '_':
  case '~':
  case ':':

  case '@': // pchar
  case '/': // separator

  // sub-delimiters:
  case '!':
  case '$':
  case '&':
  case '\'':
  case '(':
  case ')':
  case '*':
  case '+':
  case ',':
  case ';':
  case '=':
    return true;
  default:
    return false;
  }
}

static bool
is_dir_sep(const char c)
{
  #ifdef _WIN32
  return c == '\\' || c == '/';
  #else
  return c == '/';
  #endif
}

SerdNode
serd_node_new_file_uri(const uint8_t* const path,
                       const uint8_t* const hostname,
                       SerdURI* const       out,
                       const bool           escape)
{
  const size_t path_len     = strlen((const char*)path);
  const size_t hostname_len = hostname ? strlen((const char*)hostname) : 0;
  const bool   is_windows   = is_windows_path(path);
  size_t       uri_len      = 0;
  uint8_t*     uri          = NULL;

  if (is_dir_sep((char)path[0]) || is_windows) {
    uri_len = strlen("file://") + hostname_len + is_windows;
    uri     = (uint8_t*)calloc(uri_len + 1, 1);

    memcpy(uri, "file://", 7);

    if (hostname) {
      memcpy(uri + 7, hostname, hostname_len);
    }

    if (is_windows) {
      ((char*)uri)[7 + hostname_len] = '/';
    }
  }

  SerdChunk chunk = {uri, uri_len};
  for (size_t i = 0; i < path_len; ++i) {
    if (path[i] == '%') {
      serd_chunk_sink("%%", 2, &chunk);
    } else if (!escape || is_uri_path_char(path[i])) {
      serd_chunk_sink(path + i, 1, &chunk);
#ifdef _WIN32
    } else if (path[i] == '\\') {
      serd_chunk_sink("/", 1, &chunk);
#endif
    } else {
      char escape_str[4] = {'%', 0, 0, 0};
      snprintf(escape_str + 1, sizeof(escape_str) - 1, "%X", (unsigned)path[i]);
      serd_chunk_sink(escape_str, 3, &chunk);
    }
  }

  serd_chunk_sink_finish(&chunk);

  if (out) {
    serd_uri_parse(chunk.buf, out);
  }

  return serd_node_from_substring(SERD_URI, chunk.buf, chunk.len);
}

SerdNode
serd_node_new_uri(const SerdURI* const uri,
                  const SerdURI* const base,
                  SerdURI* const       out)
{
  SerdURI abs_uri = *uri;
  if (base) {
    serd_uri_resolve(uri, base, &abs_uri);
  }

  const size_t len        = serd_uri_string_length(&abs_uri);
  uint8_t*     buf        = (uint8_t*)malloc(len + 1);
  SerdNode     node       = {buf, 0, 0, 0, SERD_URI};
  uint8_t*     ptr        = buf;
  const size_t actual_len = serd_uri_serialise(&abs_uri, string_sink, &ptr);

  buf[actual_len] = '\0';
  node.n_bytes    = actual_len;
  node.n_chars    = serd_strlen(buf, NULL, NULL);

  if (out) {
    serd_uri_parse(buf, out); // TODO: cleverly avoid double parse
  }

  return node;
}

SerdNode
serd_node_new_relative_uri(const SerdURI* const uri,
                           const SerdURI* const base,
                           const SerdURI* const root,
                           SerdURI* const       out)
{
  const size_t uri_len  = serd_uri_string_length(uri);
  const size_t base_len = serd_uri_string_length(base);
  uint8_t*     buf      = (uint8_t*)malloc(uri_len + base_len + 1);
  SerdNode     node     = {buf, 0, 0, 0, SERD_URI};
  uint8_t*     ptr      = buf;
  const size_t actual_len =
    serd_uri_serialise_relative(uri, base, root, string_sink, &ptr);

  buf[actual_len] = '\0';
  node.n_bytes    = actual_len;
  node.n_chars    = serd_strlen(buf, NULL, NULL);

  if (out) {
    serd_uri_parse(buf, out); // TODO: cleverly avoid double parse
  }

  return node;
}

static unsigned
serd_digits(const double abs)
{
  const double lg = ceil(log10(floor(abs) + 1.0));
  return lg < 1.0 ? 1U : (unsigned)lg;
}

SerdNode
serd_node_new_decimal(const double d, const unsigned frac_digits)
{
  if (isnan(d) || isinf(d)) {
    return SERD_NODE_NULL;
  }

  const double   abs_d      = fabs(d);
  const unsigned int_digits = serd_digits(abs_d);
  char*          buf        = (char*)calloc(int_digits + frac_digits + 3, 1);
  SerdNode       node       = {(const uint8_t*)buf, 0, 0, 0, SERD_LITERAL};
  const double   int_part   = floor(abs_d);

  // Point s to decimal point location
  char* s = buf + int_digits;
  if (d < 0.0) {
    *buf = '-';
    ++s;
  }

  // Write integer part (right to left)
  char*    t   = s - 1;
  uint64_t dec = (uint64_t)int_part;
  do {
    *t-- = (char)('0' + dec % 10);
  } while ((dec /= 10) > 0);

  *s++ = '.';

  // Write fractional part (right to left)
  double frac_part = fabs(d - int_part);
  if (frac_part < DBL_EPSILON) {
    *s++         = '0';
    node.n_bytes = node.n_chars = (size_t)(s - buf);
  } else {
    uint64_t frac = (uint64_t)llround(frac_part * pow(10.0, (int)frac_digits));
    s += frac_digits - 1;
    unsigned i = 0;

    // Skip trailing zeros
    for (; i < frac_digits - 1 && !(frac % 10); ++i, --s, frac /= 10) {
    }

    node.n_bytes = node.n_chars = (size_t)(s - buf) + 1U;

    // Write digits from last trailing zero to decimal point
    for (; i < frac_digits; ++i) {
      *s-- = (char)('0' + (frac % 10));
      frac /= 10;
    }
  }

  return node;
}

SerdNode
serd_node_new_integer(const int64_t i)
{
  uint64_t       abs_i  = (i < 0) ? -i : i;
  const unsigned digits = serd_digits((double)abs_i);
  char*          buf    = (char*)calloc(digits + 2, 1);
  SerdNode       node   = {(const uint8_t*)buf, 0, 0, 0, SERD_LITERAL};

  // Point s to the end
  char* s = buf + digits - 1;
  if (i < 0) {
    *buf = '-';
    ++s;
  }

  node.n_bytes = node.n_chars = (size_t)(s - buf) + 1U;

  // Write integer part (right to left)
  do {
    *s-- = (char)('0' + (abs_i % 10));
  } while ((abs_i /= 10) > 0);

  return node;
}

SerdNode
serd_node_new_blob(const void* const buf,
                   const size_t      size,
                   const bool        wrap_lines)
{
  const size_t len  = serd_base64_get_length(size, wrap_lines);
  uint8_t*     str  = (uint8_t*)calloc(len + 2, 1);
  SerdNode     node = {str, len, len, 0, SERD_LITERAL};

  if (serd_base64_encode(str, buf, size, wrap_lines)) {
    node.flags |= SERD_HAS_NEWLINE;
  }

  return node;
}

void
serd_node_free(SerdNode* const node)
{
  if (node && node->buf) {
    free((uint8_t*)node->buf);
    node->buf = NULL;
  }
}