/** \file reader.h

    Prototypes for functions for reading data from stdin and passing
	to the parser. If stdin is a keyboard, it supplies a killring,
	history, syntax highlighting, tab-completion and various other
	features.
*/

#ifndef FISH_READER_H
#define FISH_READER_H

#include <vector>
#include <wchar.h>

#include "util.h"
#include "io.h"
#include "common.h"
#include "complete.h"
#include "highlight.h"
#include "parse_constants.h"

class parser_t;
class completion_t;
class history_t;

/* Helper class for storing a command line */
class editable_line_t
{
public:

    /** The command line */
    wcstring text;

    /** The current position of the cursor in the command line */
    size_t position;

    const wcstring &get_text() const
    {
        return text;
    }

    /* Gets the length of the text */
    size_t size() const
    {
        return text.size();
    }

    bool empty() const
    {
        return text.empty();
    }

    void clear()
    {
        text.clear();
        position = 0;
    }

    wchar_t at(size_t idx)
    {
        return text.at(idx);
    }

    editable_line_t() : text(), position(0)
    {
    }

    /* Inserts a substring of str given by start, len at the cursor position */
    void insert_string(const wcstring &str, size_t start = 0, size_t len = wcstring::npos);
};

/**
  Read commands from \c fd until encountering EOF
*/
int reader_read(int fd, const io_chain_t &io);

/**
  Tell the shell that it should exit after the currently running command finishes.
*/
void reader_exit(int do_exit, int force);

/**
   Check that the reader is in a sane state
*/
void reader_sanity_check();

/**
   Initialize the reader
*/
void reader_init();

/**
   Destroy and free resources used by the reader
*/
void reader_destroy();

/** Restore the term mode at startup */
void restore_term_mode();

/**
   Returns the filename of the file currently read
*/
const wchar_t *reader_current_filename();

/**
   Push a new filename on the stack of read files

   \param fn The fileanme to push
*/
void reader_push_current_filename(const wchar_t *fn);
/**
   Pop the current filename from the stack of read files
 */
void reader_pop_current_filename();

/**
   Write the title to the titlebar. This function is called just
   before a new application starts executing and just after it
   finishes.

   \param cmd Command line string passed to \c fish_title if is defined.
*/
void reader_write_title(const wcstring &cmd);

/**
   Call this function to tell the reader that a repaint is needed, and
   should be performed when possible.
 */
void reader_repaint_needed();

/** Call this function to tell the reader that some color has changed. */
void reader_react_to_color_change();

/* Repaint immediately if needed. */
void reader_repaint_if_needed();

/**
   Run the specified command with the correct terminal modes, and
   while taking care to perform job notification, set the title, etc.
*/
void reader_run_command(const wcstring &buff);

/**
   Get the string of character currently entered into the command
   buffer, or 0 if interactive mode is uninitialized.
*/
const wchar_t *reader_get_buffer();

/** Returns the current reader's history */
history_t *reader_get_history(void);

/**
   Set the string of characters in the command buffer, as well as the cursor position.

   \param b the new buffer value
   \param p the cursor position. If \c p is larger than the length of the command line,
            the cursor is placed on the last character.
*/
void reader_set_buffer(const wcstring &b, size_t p);

/**
   Get the current cursor position in the command line. If interactive
   mode is uninitialized, return (size_t)(-1).
*/
size_t reader_get_cursor_pos();


/**
   Get the current selection range in the command line.
   Returns false if there is no active selection, true otherwise.
*/
bool reader_get_selection(size_t *start, size_t *len);

/**
   Return the value of the interrupted flag, which is set by the sigint
   handler, and clear it if it was set.
*/
int reader_interrupted();

/**
   Clear the interrupted flag unconditionally without handling anything. The
   flag could have been set e.g. when an interrupt arrived just as we were
   ending an earlier \c reader_readline invocation but before the
   \c is_interactive_read flag was cleared.
*/
void reader_reset_interrupted();

/**
   Return the value of the interrupted flag, which is set by the sigint
   handler, and clear it if it was set. If the current reader is interruptible,
   call \c reader_exit().
*/
int reader_reading_interrupted();

/**
   Returns true if the current reader generation count does not equal the
   generation count the current thread was started with.
   Note 1: currently only valid for autocompletion threads! Other threads don't
   set the threadlocal generation count when they start up.
*/
bool reader_thread_job_is_stale();

/**
   Read one line of input. Before calling this function, reader_push() must have
   been called in order to set up a valid reader environment. If nchars > 0,
   return after reading that many characters even if a full line has not yet
   been read. Note: the returned value may be longer than nchars if a single
   keypress resulted in multiple characters being inserted into the commandline.
*/
const wchar_t *reader_readline(int nchars);

/**
   Push a new reader environment.
*/
void reader_push(const wchar_t *name);

/**
   Return to previous reader environment
*/
void reader_pop();

/**
   Specify function to use for finding possible tab completions. The function must take these arguments:

   - The command to be completed as a null terminated array of wchar_t
   - An array_list_t in which completions will be inserted.
*/
typedef void (*complete_function_t)(const wcstring &, std::vector<completion_t> &, completion_request_flags_t);
void reader_set_complete_function(complete_function_t);

/**
 The type of a highlight function.
 */
class env_vars_snapshot_t;
typedef void (*highlight_function_t)(const wcstring &, std::vector<highlight_spec_t> &, size_t, wcstring_list_t *, const env_vars_snapshot_t &vars);

/**
 Specify function for syntax highlighting. The function must take these arguments:

 - The command to be highlighted as a null terminated array of wchar_t
 - The color code of each character as an array of ints
 - The cursor position
 - An array_list_t used for storing error messages
 */
void reader_set_highlight_function(highlight_function_t);

/**
   Specify function for testing if the command buffer contains syntax
   errors that must be corrected before returning.
*/
void reader_set_test_function(parser_test_error_bits_t (*f)(const wchar_t *));

/**
   Specify string of shell commands to be run in order to generate the
   prompt.
*/
void reader_set_left_prompt(const wcstring &prompt);

/**
   Specify string of shell commands to be run in order to generate the
   right prompt.
*/
void reader_set_right_prompt(const wcstring &prompt);


/** Sets whether autosuggesting is allowed. */
void reader_set_allow_autosuggesting(bool flag);

/** Sets whether abbreviation expansion is performed. */
void reader_set_expand_abbreviations(bool flag);


/** Sets whether the reader should exit on ^C. */
void reader_set_exit_on_interrupt(bool flag);

/**
   Returns true if the shell is exiting, 0 otherwise.
*/
bool shell_is_exiting();

/**
   The readers interrupt signal handler. Cancels all currently running blocks.
*/
void reader_handle_int(int signal);

/**
   This function returns true if fish is exiting by force, i.e. because stdin died
*/
int reader_exit_forced();

/**
   Test if the given shell command contains errors. Uses parser_test
   for testing. Suitable for reader_set_test_function().
*/
parser_test_error_bits_t reader_shell_test(const wchar_t *b);

/**
   Test whether the interactive reader is in search mode.

   \return 0 if not in search mode, 1 if in search mode and -1 if not in interactive mode
 */
int reader_search_mode();

/**
   Test whether the interactive reader has visible pager contents.

   \return 0 if it has pager contents, 1 if it does not have pager contents, and -1 if not in interactive mode
 */
int reader_has_pager_contents();


/* Given a command line and an autosuggestion, return the string that gets shown to the user. Exposed for testing purposes only. */
wcstring combine_command_and_autosuggestion(const wcstring &cmdline, const wcstring &autosuggestion);

/* Expand abbreviations at the given cursor position. Exposed for testing purposes only. */
bool reader_expand_abbreviation_in_command(const wcstring &cmdline, size_t cursor_pos, wcstring *output);

/* Apply a completion string. Exposed for testing only. */
wcstring completion_apply_to_command_line(const wcstring &val_str, complete_flags_t flags, const wcstring &command_line, size_t *inout_cursor_pos, bool append_only);

#endif