/** \file tokenizer.h

    A specialized tokenizer for tokenizing the fish language. In the
    future, the tokenizer should be extended to support marks,
    tokenizing multiple strings and disposing of unused string
    segments.
*/

#ifndef FISH_TOKENIZER_H
#define FISH_TOKENIZER_H

#include <wchar.h>

/**
   Token types
*/
enum token_type
{
    TOK_NONE, /**< Tokenizer not yet constructed */
    TOK_ERROR, /**< Error reading token */
    TOK_INVALID,/**< Invalid token */
    TOK_STRING,/**< String token */
    TOK_PIPE,/**< Pipe token */
    TOK_END,/**< End token */
    TOK_REDIRECT_OUT, /**< redirection token */
    TOK_REDIRECT_APPEND,/**< redirection append token */
    TOK_REDIRECT_IN,/**< input redirection token */
    TOK_REDIRECT_FD,/**< redirection to new fd token */
    TOK_REDIRECT_NOCLOB, /**<? redirection token */
    TOK_BACKGROUND,/**< send job to bg token */
    TOK_COMMENT/**< comment token */
};

/**
   Tokenizer error types
*/
enum tokenizer_error
{
    TOK_UNTERMINATED_QUOTE,
    TOK_UNTERMINATED_SUBSHELL,
    TOK_UNTERMINATED_ESCAPE,
    TOK_OTHER
}
;


/**
   Flag telling the tokenizer to accept incomplete parameters,
   i.e. parameters with mismatching paranthesis, etc. This is useful
   for tab-completion.
*/
#define TOK_ACCEPT_UNFINISHED 1

/**
   Flag telling the tokenizer not to remove comments. Useful for
   syntax highlighting.
*/
#define TOK_SHOW_COMMENTS 2

/** Flag telling the tokenizer to not generate error messages, which we need to do when tokenizing off of the main thread (since wgettext is not thread safe).
*/
#define TOK_SQUASH_ERRORS 4

typedef unsigned int tok_flags_t;

/**
   The tokenizer struct.
*/
struct tokenizer_t
{
    /** A pointer into the original string, showing where the next token begins */
    const wchar_t *buff;
    /** A copy of the original string */
    const wchar_t *orig_buff;
    /** A pointer to the last token*/
    wchar_t *last;

    /** Type of last token*/
    int last_type;
    /** Length of last token*/
    size_t last_len;
    /** Offset of last token*/
    size_t last_pos;
    /** Whether there are more tokens*/
    bool has_next;
    /** Whether incomplete tokens are accepted*/
    bool accept_unfinished;
    /** Whether commants should be returned*/
    bool show_comments;
    /** Type of last quote, can be either ' or ".*/
    wchar_t last_quote;
    /** Last error */
    int error;
    /* Whether we are squashing errors */
    bool squash_errors;

    /* Cached line number information */
    size_t cached_lineno_offset;
    int cached_lineno_count;

    /** Return the line number of the character at the given offset */
    int line_number_of_character_at_offset(size_t offset);

    /**
      Constructor for a tokenizer. b is the string that is to be
      tokenized. It is not copied, and should not be freed by the caller
      until after the tokenizer is destroyed.

      \param b The string to tokenize
      \param flags Flags to the tokenizer. Setting TOK_ACCEPT_UNFINISHED will cause the tokenizer
      to accept incomplete tokens, such as a subshell without a closing
      parenthesis, as a valid token. Setting TOK_SHOW_COMMENTS will return comments as tokens

    */
    tokenizer_t(const wchar_t *b, tok_flags_t flags);
};

/**
  Jump to the next token.
*/
void tok_next(tokenizer_t *tok);

/**
  Returns the type of the last token. Must be one of the values in the token_type enum.
*/
int tok_last_type(tokenizer_t *tok);

/**
  Returns the last token string. The string should not be freed by the caller.
*/
wchar_t *tok_last(tokenizer_t *tok);

/**
  Returns the type of quote from the last TOK_QSTRING
*/
wchar_t tok_last_quote(tokenizer_t *tok);

/**
  Returns true as long as there are more tokens left
*/
int tok_has_next(tokenizer_t *tok);

/**
  Returns the position of the beginning of the current token in the original string
*/
int tok_get_pos(tokenizer_t *tok);

/**
   Destroy the tokenizer and free asociated memory
*/
void tok_destroy(tokenizer_t *tok);


/**
   Returns the original string to tokenizer
 */
const wchar_t *tok_string(tokenizer_t *tok);


/**
   Returns only the first token from the specified string. This is a
   convenience function, used to retrieve the first token of a
   string. This can be useful for error messages, etc.

   The string should be freed. After use.
*/
wchar_t *tok_first(const wchar_t *str);

/**
   Indicates whether a character can be part of a string, or is a string separator.
   Separators include newline, tab, |, ^, >, <, etc.

   is_first should indicate whether this is the first character in a potential string.
*/
bool tok_is_string_character(wchar_t c, bool is_first);

/**
   Move tokenizer position
*/
void tok_set_pos(tokenizer_t *tok, int pos);

/**
   Returns a string description of the specified token type
*/
const wchar_t *tok_get_desc(int type);

/**
   Get tokenizer error type. Should only be called if tok_last_tope returns TOK_ERROR.
*/
int tok_get_error(tokenizer_t *tok);


#endif