#include <assert.h>
#include <ruby.h>

#if defined(_WIN32)
#include <stddef.h>
#endif

#ifdef HAVE_RUBY_RE_H
#include <ruby/re.h>
#else
#include <re.h>
#endif

#ifdef HAVE_RUBY_ENCODING_H
#include <ruby/encoding.h>
#define ENCODED_STR_NEW(ptr, len) \
    rb_enc_str_new(ptr, len, rb_utf8_encoding())
#else
#define ENCODED_STR_NEW(ptr, len) \
    rb_str_new(ptr, len)
#endif

#define LF_FLAG      0
#define CRLF_FLAG    1
#define LF           "\n"
#define CRLF         "\r\n"

#ifndef RSTRING_PTR
#define RSTRING_PTR(s) (RSTRING(s)->ptr)
#endif

#ifndef RSTRING_LEN
#define RSTRING_LEN(s) (RSTRING(s)->len)
#endif

#define DATA_GET(FROM, TYPE, NAME) \
  Data_Get_Struct(FROM, TYPE, NAME); \
  if (NAME == NULL) { \
    rb_raise(rb_eArgError, "NULL found for " # NAME " when it shouldn't be."); \
  }
 
typedef struct lexer_state {
  int content_len;
  int line_number;
  int current_line;
  int start_col;
  int eol;
  size_t mark;
  size_t keyword_start;
  size_t keyword_end;
  size_t next_keyword_start;
  size_t content_start;
  size_t content_end;
  size_t query_start;
  size_t last_newline;
  size_t final_newline;
} lexer_state;

static VALUE mGherkin;
static VALUE mGherkinLexer;
static VALUE mCLexer;
static VALUE cI18nLexer;
static VALUE rb_eGherkinLexingError;

#define LEN(AT, P) (P - data - lexer->AT)
#define MARK(M, P) (lexer->M = (P) - data)
#define PTR_TO(P) (data + lexer->P)

#define STORE_KW_END_CON(EVENT) \
  store_multiline_kw_con(listener, # EVENT, \
    PTR_TO(keyword_start), LEN(keyword_start, PTR_TO(keyword_end - 1)), \
    PTR_TO(content_start), LEN(content_start, PTR_TO(content_end)), \
    lexer->current_line, lexer->eol); \
    if (lexer->content_end != 0) { \
      p = PTR_TO(content_end - 1); \
    } \
    lexer->content_end = 0

#define STORE_ATTR(ATTR) \
    store_attr(listener, # ATTR, \
      PTR_TO(content_start), LEN(content_start, p), \
      lexer->line_number)

%%{
  machine lexer;
 
  action begin_content {
		MARK(content_start, p);
    lexer->current_line = lexer->line_number;
  }
  
  action begin_pystring_content {
    MARK(content_start, p);
  }

  action start_pystring {
    lexer->current_line = lexer->line_number;
    lexer->start_col = p - data - lexer->last_newline;
  }
 
  action store_pystring_content {
    int len = LEN(content_start, PTR_TO(final_newline));

    if (len < 0) len = 0;

    store_pystring_content(listener, lexer->start_col, PTR_TO(content_start), len, lexer->current_line);
  } 
 
  action store_feature_content {
    STORE_KW_END_CON(feature);
  }
  
  action store_background_content {
    STORE_KW_END_CON(background);
  }
  
  action store_scenario_content {
    STORE_KW_END_CON(scenario);
  }
  
  action store_scenario_outline_content {
    STORE_KW_END_CON(scenario_outline);
  }
  
  action store_examples_content {
    STORE_KW_END_CON(examples);
  }
  
  action store_step_content {
    store_kw_con(listener, "step",
      PTR_TO(keyword_start), LEN(keyword_start, PTR_TO(keyword_end)),
      PTR_TO(content_start), LEN(content_start, p), 
      lexer->current_line);
  }
  
  action store_comment_content {
    STORE_ATTR(comment);
    lexer->mark = 0;
  }
  
  action store_tag_content {
    STORE_ATTR(tag);
    lexer->mark = 0;
  }
  
  action inc_line_number {
    lexer->line_number += 1;
    MARK(final_newline, p);
  }
    
  action last_newline {
    MARK(last_newline, p + 1);
  }
 
  action start_keyword {
    if (lexer->mark == 0) {
      MARK(mark, p);
    }
  }
  
  action end_keyword {
    MARK(keyword_end, p);
    MARK(keyword_start, PTR_TO(mark));
    MARK(content_start, p + 1);
    lexer->mark = 0;
  }
  
  action next_keyword_start {
    MARK(content_end, p);
  }

  action start_row {
    p = p - 1;
    lexer->current_line = lexer->line_number;
    current_row = rb_ary_new();
  }
  
  action begin_cell_content {
		MARK(content_start, p);
  }

  action store_cell_content {
    VALUE con = ENCODED_STR_NEW(PTR_TO(content_start), LEN(content_start, p));
    rb_funcall(con, rb_intern("strip!"), 0);
    VALUE re_pipe      = rb_reg_regcomp(rb_str_new2("\\\\\\|"));
    VALUE re_backslash = rb_reg_regcomp(rb_str_new2("\\\\\\\\"));
    rb_funcall(con, rb_intern("gsub!"), 2, re_pipe,      rb_str_new2("|"));
    rb_funcall(con, rb_intern("gsub!"), 2, re_backslash, rb_str_new2("\\"));

    rb_ary_push(current_row, con);
  }

  action store_row {
    rb_funcall(listener, rb_intern("row"), 2, current_row, INT2FIX(lexer->current_line));
  }

  action end_feature {
    if (cs < lexer_first_final) {
      if (raise_lexer_error != NULL) {
        size_t count = 0;
    	VALUE newstr_val;
        char *newstr;
        int newstr_count = 0;        
        size_t len;
        const char *buff;
        if (lexer->last_newline != 0) {
          len = LEN(last_newline, eof);
          buff = PTR_TO(last_newline);
        } else {
          len = strlen(data);
          buff = data;
        }

        // Allocate as a ruby string so that it gets cleaned up by GC
        newstr_val = rb_str_new(buff, len);
        newstr = RSTRING_PTR(newstr_val);

        for (count = 0; count < len; count++) {
          if(buff[count] == 10) {
            newstr[newstr_count] = '\0'; // terminate new string at first newline found
            break;
          } else {
            if (buff[count] == '%') {
              newstr[newstr_count++] = buff[count];
              newstr[newstr_count] = buff[count];
            } else {
              newstr[newstr_count] = buff[count];
            }
          }
          newstr_count++;
        }

        int line = lexer->line_number;
        lexer_init(lexer); // Re-initialize so we can scan again with the same lexer
        raise_lexer_error(newstr, line);
      }
    } else {
      rb_funcall(listener, rb_intern("eof"), 0);
    }
  }

  include lexer_common "lexer_common.<%= @i18n.underscored_iso_code %>.rl";   

}%%

/** Data **/
%% write data;

static VALUE 
strip_i(VALUE str, VALUE ary)
{
  rb_funcall(str, rb_intern("strip!"), 0);
  rb_ary_push(ary, str);
  
  return Qnil;
}

static VALUE 
multiline_strip(VALUE text)
{
  VALUE map = rb_ary_new();
  VALUE split = rb_str_split(text, "\n");
  
  rb_iterate(rb_each, split, strip_i, map);
  
  return split;
}

static void 
store_kw_con(VALUE listener, const char * event_name, 
             const char * keyword_at, size_t keyword_length, 
             const char * at,         size_t length, 
             int current_line)
{
  VALUE con = Qnil, kw = Qnil;
  kw = ENCODED_STR_NEW(keyword_at, keyword_length);
  con = ENCODED_STR_NEW(at, length);
  rb_funcall(con, rb_intern("strip!"), 0);
  rb_funcall(listener, rb_intern(event_name), 3, kw, con, INT2FIX(current_line)); 
}

static void
store_multiline_kw_con(VALUE listener, const char * event_name,
                      const char * keyword_at, size_t keyword_length,
                      const char * at,         size_t length,
                      int current_line, int eol)
{
  VALUE con = Qnil, kw = Qnil, name = Qnil, desc = Qnil;

  kw = ENCODED_STR_NEW(keyword_at, keyword_length);
  con = ENCODED_STR_NEW(at, length);

  VALUE split = multiline_strip(con);
  
  name = rb_funcall(split, rb_intern("shift"), 0);
  desc = rb_ary_join(split, rb_str_new2( \
          eol == CRLF_FLAG ? CRLF : LF ));

  if( name == Qnil ) 
  {
    name = rb_str_new2("");
  }
  if( rb_funcall(desc, rb_intern("size"), 0) == 0) 
  {
    desc = rb_str_new2("");
  }
  rb_funcall(name, rb_intern("strip!"), 0);
  rb_funcall(desc, rb_intern("strip!"), 0);
  rb_funcall(listener, rb_intern(event_name), 4, kw, name, desc, INT2FIX(current_line)); 
}

static void 
store_attr(VALUE listener, const char * attr_type,
           const char * at, size_t length, 
           int line)
{
  VALUE val = ENCODED_STR_NEW(at, length);
  rb_funcall(listener, rb_intern(attr_type), 2, val, INT2FIX(line));
}

static void 
store_pystring_content(VALUE listener, 
          int start_col, 
          const char *at, size_t length, 
          int current_line)
{
  VALUE con = ENCODED_STR_NEW(at, length);
  // Gherkin will crash gracefully if the string representation of start_col pushes the pattern past 32 characters
  char pat[32]; 
  snprintf(pat, 32, "^[\t ]{0,%d}", start_col); 
  VALUE re = rb_reg_regcomp(rb_str_new2(pat));
  VALUE re2 = rb_reg_regcomp(rb_str_new2("\r\\Z"));
  VALUE unescape_escaped_quotes = rb_reg_regcomp(rb_str_new2("\\\\\"\\\\\"\\\\\""));
  rb_funcall(con, rb_intern("gsub!"), 2, re, rb_str_new2(""));
  rb_funcall(con, rb_intern("sub!"), 2, re2, rb_str_new2(""));
  rb_funcall(con, rb_intern("gsub!"), 2, unescape_escaped_quotes, rb_str_new2("\"\"\""));
  rb_funcall(listener, rb_intern("py_string"), 2, con, INT2FIX(current_line));
}

static void 
raise_lexer_error(const char * at, int line)
{ 
  rb_raise(rb_eGherkinLexingError, "Lexing error on line %d: '%s'. See http://wiki.github.com/aslakhellesoy/gherkin/lexingerror for more information.", line, at);
}

static int 
count_char(char char_to_count, char *str) {

  int count = 0;
  int i = 0;
  while(str[i] != '\0') {
    if(str[i] == char_to_count) {
      count++;
    }
    i++;
  }
  return count;
}

static void lexer_init(lexer_state *lexer) {
  lexer->content_start = 0;
  lexer->content_end = 0;
  lexer->content_len = 0;
  lexer->mark = 0;
  lexer->keyword_start = 0;
  lexer->keyword_end = 0;
  lexer->next_keyword_start = 0;
  lexer->line_number = 1;
  lexer->last_newline = 0;
  lexer->final_newline = 0;
  lexer->start_col = 0;
  lexer->eol = LF_FLAG;
}

static VALUE CLexer_alloc(VALUE klass)
{
  VALUE obj;
  lexer_state *lxr = ALLOC(lexer_state);
  lexer_init(lxr);

  obj = Data_Wrap_Struct(klass, NULL, -1, lxr);

  return obj;
}

static VALUE CLexer_init(VALUE self, VALUE listener)
{
  rb_iv_set(self, "@listener", listener);
  
  lexer_state *lxr = NULL;
  DATA_GET(self, lexer_state, lxr);
  lexer_init(lxr);
  
  return self;
}

static VALUE CLexer_scan(VALUE self, VALUE input)
{
  VALUE listener = rb_iv_get(self, "@listener");

  lexer_state *lexer = NULL;
  DATA_GET(self, lexer_state, lexer);

  VALUE input_copy = rb_str_dup(input);

  rb_str_append(input_copy, rb_str_new2("\n%_FEATURE_END_%"));
  char *data = RSTRING_PTR(input_copy);
  size_t len = RSTRING_LEN(input_copy);
  
  if (count_char('\r', data) > (count_char('\n', data) / 2)) {
    lexer->eol = CRLF_FLAG;
  }
  
  if (len == 0) { 
    rb_raise(rb_eGherkinLexingError, "No content to lex.");
  } else {

    const char *p, *pe, *eof;
    int cs = 0;
    
    VALUE current_row = Qnil;

    p = data;
    pe = data + len;
    eof = pe;
    
    assert(*pe == '\0' && "pointer does not end on NULL");
    
    %% write init;
    %% write exec;

    assert(p <= pe && "data overflow after parsing execute");
    assert(lexer->content_start <= len && "content starts after data end");
    assert(lexer->mark < len && "mark is after data end");
    
    // Reset lexer by re-initializing the whole thing
    lexer_init(lexer);

    if (cs == lexer_error) {
      rb_raise(rb_eGherkinLexingError, "Invalid format, lexing fails.");
    } else {
      return Qtrue;
    }
  }
}

void Init_gherkin_lexer_<%= @i18n.underscored_iso_code %>()
{
  mGherkin = rb_define_module("Gherkin");
  mGherkinLexer = rb_define_module_under(mGherkin, "Lexer");
  rb_eGherkinLexingError = rb_const_get(mGherkinLexer, rb_intern("LexingError"));

  mCLexer = rb_define_module_under(mGherkin, "CLexer");
  cI18nLexer = rb_define_class_under(mCLexer, "<%= @i18n.underscored_iso_code.capitalize %>", rb_cObject);
  rb_define_alloc_func(cI18nLexer, CLexer_alloc);
  rb_define_method(cI18nLexer, "initialize", CLexer_init, 1);
  rb_define_method(cI18nLexer, "scan", CLexer_scan, 1);
}