/* SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup sptext
 */

#include <string.h>

#include "BLI_blenlib.h"

#include "DNA_space_types.h"
#include "DNA_text_types.h"

#include "BKE_text.h"

#include "text_format.h"

/* *** Local Functions (for format_line) *** */

static int txtfmt_osl_find_builtinfunc(const char *string)
{
  int i, len;

  /* Keep aligned args for readability. */
  /* clang-format off */

  /* list is from
   * https://github.com/imageworks/OpenShadingLanguage/raw/master/src/doc/osl-languagespec.pdf
   */
  if        (STR_LITERAL_STARTSWITH(string, "break",        len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "closure",      len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "color",        len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "continue",     len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "do",           len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "else",         len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "emit",         len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "float",        len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "for",          len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "if",           len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "illuminance",  len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "illuminate",   len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "int",          len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "matrix",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "normal",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "output",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "point",        len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "public",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "return",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "string",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "struct",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "vector",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "void",         len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "while",        len)) { i = len;
  } else                                                          { i = 0;
  }

  /* clang-format on */

  /* If next source char is an identifier (eg. 'i' in "definite") no match */
  if (i == 0 || text_check_identifier(string[i])) {
    return -1;
  }
  return i;
}

static int txtfmt_osl_find_reserved(const char *string)
{
  int i, len;

  /* Keep aligned args for readability. */
  /* clang-format off */

  /* list is from...
   * https://github.com/imageworks/OpenShadingLanguage/raw/master/src/doc/osl-languagespec.pdf
   */
  if        (STR_LITERAL_STARTSWITH(string, "bool",         len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "case",         len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "catch",        len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "char",         len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "const",        len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "delete",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "default",      len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "double",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "enum",         len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "extern",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "false",        len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "friend",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "goto",         len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "inline",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "long",         len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "new",          len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "operator",     len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "private",      len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "protected",    len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "short",        len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "signed",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "sizeof",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "static",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "switch",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "template",     len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "this",         len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "throw",        len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "true",         len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "try",          len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "typedef",      len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "uniform",      len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "union",        len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "unsigned",     len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "varying",      len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "virtual",      len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "volatile",     len)) { i = len;
  } else                                                          { i = 0;
  }

  /* clang-format on */

  /* If next source char is an identifier (eg. 'i' in "definite") no match */
  if (i == 0 || text_check_identifier(string[i])) {
    return -1;
  }
  return i;
}

/* Checks the specified source string for a OSL special name. This name must
 * start at the beginning of the source string and must be followed by a non-
 * identifier (see text_check_identifier(char)) or null character.
 *
 * If a special name is found, the length of the matching name is returned.
 * Otherwise, -1 is returned. */

static int txtfmt_osl_find_specialvar(const char *string)
{
  int i, len;

  /* Keep aligned args for readability. */
  /* clang-format off */

  /* OSL shader types */
  if        (STR_LITERAL_STARTSWITH(string, "shader",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "surface",      len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "volume",       len)) { i = len;
  } else if (STR_LITERAL_STARTSWITH(string, "displacement", len)) { i = len;
  } else                                                          { i = 0;
  }

  /* clang-format on */

  /* If next source char is an identifier (eg. 'i' in "definite") no match */
  if (i == 0 || text_check_identifier(string[i])) {
    return -1;
  }
  return i;
}

/* matches py 'txtfmt_osl_find_decorator' */
static int txtfmt_osl_find_preprocessor(const char *string)
{
  if (string[0] == '#') {
    int i = 1;
    /* White-space is ok '#  foo'. */
    while (text_check_whitespace(string[i])) {
      i++;
    }
    while (text_check_identifier(string[i])) {
      i++;
    }
    return i;
  }
  return -1;
}

static char txtfmt_osl_format_identifier(const char *str)
{
  char fmt;

  /* Keep aligned args for readability. */
  /* clang-format off */

  if        (txtfmt_osl_find_specialvar(str)   != -1) { fmt = FMT_TYPE_SPECIAL;
  } else if (txtfmt_osl_find_builtinfunc(str)  != -1) { fmt = FMT_TYPE_KEYWORD;
  } else if (txtfmt_osl_find_reserved(str)     != -1) { fmt = FMT_TYPE_RESERVED;
  } else if (txtfmt_osl_find_preprocessor(str) != -1) { fmt = FMT_TYPE_DIRECTIVE;
  } else                                              { fmt = FMT_TYPE_DEFAULT;
  }

  /* clang-format on */

  return fmt;
}

static void txtfmt_osl_format_line(SpaceText *st, TextLine *line, const bool do_next)
{
  FlattenString fs;
  const char *str;
  char *fmt;
  char cont_orig, cont, find, prev = ' ';
  int len, i;

  /* Get continuation from previous line */
  if (line->prev && line->prev->format != NULL) {
    fmt = line->prev->format;
    cont = fmt[strlen(fmt) + 1]; /* Just after the null-terminator */
    BLI_assert((FMT_CONT_ALL & cont) == cont);
  }
  else {
    cont = FMT_CONT_NOP;
  }

  /* Get original continuation from this line */
  if (line->format != NULL) {
    fmt = line->format;
    cont_orig = fmt[strlen(fmt) + 1]; /* Just after the null-terminator */
    BLI_assert((FMT_CONT_ALL & cont_orig) == cont_orig);
  }
  else {
    cont_orig = 0xFF;
  }

  len = flatten_string(st, &fs, line->line);
  str = fs.buf;
  if (!text_check_format_len(line, len)) {
    flatten_string_free(&fs);
    return;
  }
  fmt = line->format;

  while (*str) {
    /* Handle escape sequences by skipping both \ and next char */
    if (*str == '\\') {
      *fmt = prev;
      fmt++;
      str++;
      if (*str == '\0') {
        break;
      }
      *fmt = prev;
      fmt++;
      str += BLI_str_utf8_size_safe(str);
      continue;
    }
    /* Handle continuations */
    if (cont) {
      /* C-Style comments */
      if (cont & FMT_CONT_COMMENT_C) {
        if (*str == '*' && *(str + 1) == '/') {
          *fmt = FMT_TYPE_COMMENT;
          fmt++;
          str++;
          *fmt = FMT_TYPE_COMMENT;
          cont = FMT_CONT_NOP;
        }
        else {
          *fmt = FMT_TYPE_COMMENT;
        }
        /* Handle other comments */
      }
      else {
        find = (cont & FMT_CONT_QUOTEDOUBLE) ? '"' : '\'';
        if (*str == find) {
          cont = 0;
        }
        *fmt = FMT_TYPE_STRING;
      }

      str += BLI_str_utf8_size_safe(str) - 1;
    }
    /* Not in a string... */
    else {
      /* Deal with comments first */
      if (*str == '/' && *(str + 1) == '/') {
        /* fill the remaining line */
        text_format_fill(&str, &fmt, FMT_TYPE_COMMENT, len - (int)(fmt - line->format));
      }
      /* C-Style (multi-line) comments */
      else if (*str == '/' && *(str + 1) == '*') {
        cont = FMT_CONT_COMMENT_C;
        *fmt = FMT_TYPE_COMMENT;
        fmt++;
        str++;
        *fmt = FMT_TYPE_COMMENT;
      }
      else if (ELEM(*str, '"', '\'')) {
        /* Strings */
        find = *str;
        cont = (*str == '"') ? FMT_CONT_QUOTEDOUBLE : FMT_CONT_QUOTESINGLE;
        *fmt = FMT_TYPE_STRING;
      }
      /* White-space (all white-space has been converted to spaces). */
      else if (*str == ' ') {
        *fmt = FMT_TYPE_WHITESPACE;
      }
      /* Numbers (digits not part of an identifier and periods followed by digits) */
      else if ((prev != FMT_TYPE_DEFAULT && text_check_digit(*str)) ||
               (*str == '.' && text_check_digit(*(str + 1)))) {
        *fmt = FMT_TYPE_NUMERAL;
      }
      /* Punctuation */
      else if ((*str != '#') && text_check_delim(*str)) {
        *fmt = FMT_TYPE_SYMBOL;
      }
      /* Identifiers and other text (no previous white-space or delimiters. so text continues). */
      else if (prev == FMT_TYPE_DEFAULT) {
        str += BLI_str_utf8_size_safe(str) - 1;
        *fmt = FMT_TYPE_DEFAULT;
      }
      /* Not white-space, a digit, punctuation, or continuing text.
       * Must be new, check for special words. */
      else {
        /* Keep aligned arguments for readability. */
        /* clang-format off */

        /* Special vars(v) or built-in keywords(b) */
        /* keep in sync with `txtfmt_osl_format_identifier()`. */
        if        ((i = txtfmt_osl_find_specialvar(str))   != -1) { prev = FMT_TYPE_SPECIAL;
        } else if ((i = txtfmt_osl_find_builtinfunc(str))  != -1) { prev = FMT_TYPE_KEYWORD;
        } else if ((i = txtfmt_osl_find_reserved(str))     != -1) { prev = FMT_TYPE_RESERVED;
        } else if ((i = txtfmt_osl_find_preprocessor(str)) != -1) { prev = FMT_TYPE_DIRECTIVE;
        }

        /* clang-format on */

        if (i > 0) {
          if (prev == FMT_TYPE_DIRECTIVE) { /* can contain utf8 */
            text_format_fill(&str, &fmt, prev, i);
          }
          else {
            text_format_fill_ascii(&str, &fmt, prev, i);
          }
        }
        else {
          str += BLI_str_utf8_size_safe(str) - 1;
          *fmt = FMT_TYPE_DEFAULT;
        }
      }
    }
    prev = *fmt;
    fmt++;
    str++;
  }

  /* Terminate and add continuation char */
  *fmt = '\0';
  fmt++;
  *fmt = cont;

  /* If continuation has changed and we're allowed, process the next line */
  if (cont != cont_orig && do_next && line->next) {
    txtfmt_osl_format_line(st, line->next, do_next);
  }

  flatten_string_free(&fs);
}

void ED_text_format_register_osl(void)
{
  static TextFormatType tft = {NULL};
  static const char *ext[] = {"osl", NULL};

  tft.format_identifier = txtfmt_osl_format_identifier;
  tft.format_line = txtfmt_osl_format_line;
  tft.ext = ext;

  ED_text_format_register(&tft);
}