//===-- ELWrapper.cpp -------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// this file is only relevant for Visual C++
#if defined( _MSC_VER )

#include "lldb/Host/windows/windows.h"

#include "ELWrapper.h"
#include <vector>
#include <assert.h>

// index one of the variable arguments
//  presuming "(EditLine *el, ..." is first in the argument list
#define GETARG( X ) ( (void* ) *( ( (int**) &el ) + ((X) + 2) ) )

// edit line EL_ADDFN function pointer type
typedef unsigned char (*el_addfn_func)(EditLine *e, int ch);

// edit line wrapper binding container
struct el_binding
{
    //
    const char   *name;
    const char   *help;
    // function pointer to callback routine
    el_addfn_func func;
    // ascii key this function is bound to
    const char   *key;
};

// stored key bindings
static std::vector<el_binding*> _bindings;

//TODO: this should infact be related to the exact edit line context we create
static void *clientData = NULL;

// store the current prompt string
// default to what we expect to receive anyway
static const char *_prompt = "(lldb) ";

#if !defined( _WIP_INPUT_METHOD )

static char *
el_get_s (char *buffer, int chars)
{
    return gets_s(buffer, chars);
}
#else

static void
con_output (char _in)
{
    HANDLE hout = GetStdHandle( STD_OUTPUT_HANDLE );
    DWORD written = 0;
    // get the cursor position
    CONSOLE_SCREEN_BUFFER_INFO info;
    GetConsoleScreenBufferInfo( hout, &info );
    // output this char
    WriteConsoleOutputCharacterA( hout, &_in, 1, info.dwCursorPosition, &written );
    // advance cursor position
    info.dwCursorPosition.X++;
    SetConsoleCursorPosition( hout, info.dwCursorPosition );
}

static void
con_backspace (void)
{
    HANDLE hout = GetStdHandle( STD_OUTPUT_HANDLE );
    DWORD written = 0;
    // get cursor position
    CONSOLE_SCREEN_BUFFER_INFO info;
    GetConsoleScreenBufferInfo( hout, &info );
    // nudge cursor backwards
    info.dwCursorPosition.X--;
    SetConsoleCursorPosition( hout, info.dwCursorPosition );
    // blank out the last character
    WriteConsoleOutputCharacterA( hout, " ", 1, info.dwCursorPosition, &written );
}

static void
con_return (void)
{
    HANDLE hout = GetStdHandle( STD_OUTPUT_HANDLE );
    DWORD written = 0;
    // get cursor position
    CONSOLE_SCREEN_BUFFER_INFO info;
    GetConsoleScreenBufferInfo( hout, &info );
    // move onto the new line
    info.dwCursorPosition.X = 0;
    info.dwCursorPosition.Y++;
    SetConsoleCursorPosition( hout, info.dwCursorPosition );
}

static bool
runBind (char _key)
{
    for ( int i=0; i<_bindings.size(); i++ )
    {
        el_binding *bind = _bindings[i];
        if ( bind->key[0] == _key )
        {
            bind->func( (EditLine*) -1, _key );
            return true;
        }
    }
    return false;
}

// replacement get_s which is EL_BIND aware
static char *
el_get_s (char *buffer, int chars)
{
    //
    char *head = buffer;
    //
    for ( ;; Sleep( 10 ) )
    {
        //
        INPUT_RECORD _record;
        //
        DWORD _read = 0;
        if ( ReadConsoleInputA( GetStdHandle( STD_INPUT_HANDLE ), &_record, 1, &_read ) == FALSE )
            break;
        // if we didnt read a key
        if ( _read == 0 )
            continue;
        // only interested in key events
        if ( _record.EventType != KEY_EVENT )
            continue;
        // is the key down
        if (! _record.Event.KeyEvent.bKeyDown )
            continue;
        // read the ascii key character
        char _key = _record.Event.KeyEvent.uChar.AsciiChar;
        // non ascii conformant key press
        if ( _key == 0 )
        {
            // check the scan code
            // if VK_UP scroll back through history
            // if VK_DOWN scroll forward through history
            continue;
        }
        // try to execute any bind this key may have
        if ( runBind( _key ) )
            continue;
        // if we read a return key
        if ( _key == '\n' || _key == '\r' )
        {
            con_return( );
            break;
        }
        // key is backspace
        if ( _key == 0x8 )
        {
            // avoid deleting past beginning
            if ( head > buffer )
            {
                con_backspace( );
                head--;
            }
            continue;
        }

        // add this key to the input buffer
        if ( (head-buffer) < (chars-1) )
        {
            con_output( _key );
            *(head++) = _key;
        }
    }
    // insert end of line character
    *head = '\0';

    return buffer;
}
#endif

// edit line initalise
EditLine *
el_init (const char *, FILE *, FILE *, FILE *)
{
    //
    SetConsoleTitleA( "lldb" );
    // return dummy handle
    return (EditLine*) -1;
}

const char *
el_gets (EditLine *el, int *length)
{
    // print the prompt if we have one
    if ( _prompt != NULL )
        printf( _prompt );
    // create a buffer for the user input
    char *buffer = new char[ MAX_PATH ];
    // try to get user input string
    if ( el_get_s( buffer, MAX_PATH ) )
    {
        // get the string length in 'length'
        while ( buffer[ *length ] != '\0' )
            (*length)++;
        // return the input buffer
        // remember that this memory has the be free'd somewhere
        return buffer;
    }
    else
    {
        // on error
        delete [] buffer;
        return NULL;
    }
}

int
el_set (EditLine *el, int code, ...)
{
    int **arg = (int**) &el;
    //
    switch ( code )
    {
    // edit line set prompt message
    case ( EL_PROMPT ):
        {
            // EL_PROMPT, char *(*f)( EditLine *)
            //      define a prompt printing function as 'f', which is to return a string that
            //      contains the prompt.

            // get the function pointer from the arg list
            void *func_vp = (void*) *(arg+2);
            // cast to suitable prototype
            const char* (*func_fp)(EditLine*) = (const char*(*)(EditLine *)) func_vp;
            // call to get the prompt as a string
            _prompt = func_fp( el );
        }
        break;
    case ( EL_EDITOR ):
        {
            // EL_EDITOR, const char *mode
            //      set editing mode to "emacs" or "vi"
        }
        break;
    case ( EL_HIST ):
        {
            // EL_HIST, History *(*fun)(History *, int op, ... ), const char *ptr
            //      defines which histroy function to use, which is usualy history(). Ptr should be the
            //      value returned by history_init().
        }
        break;
    case ( EL_ADDFN ):
        {
            // EL_ADDFN, const char *name, const char *help, unsigned char (*func)(EditLine *e, int ch)
            //      add a user defined function, func), referred to as 'name' which is invoked when a key which is bound to 'name' is
            //      entered. 'help' is a description of 'name'. at involcation time, 'ch' is the key which caused the invocation. the
            //      return value of 'func()' should be one of:
            //          CC_NORM         add a normal character
            //          CC_NEWLINE      end of line was entered
            //          CC_EOF          EOF was entered
            //          CC_ARGHACK      expecting further command input as arguments, do nothing visually.
            //          CC_REFRESH      refresh display.
            //          CC_REFRESH_BEEP refresh display and beep.
            //          CC_CURSOR       cursor moved so update and perform CC_REFRESH
            //          CC_REDISPLAY        redisplay entire input line. this is usefull if a key binding outputs extra information.
            //          CC_ERROR            an error occured. beep and flush tty.
            //          CC_FATAL            fatal error, reset tty to known state.

            el_binding *binding = new el_binding;
            binding->name = (const char *)  GETARG( 0 );
            binding->help = (const char *)  GETARG( 1 );
            binding->func = (el_addfn_func) GETARG( 2 );
            binding->key  = 0;
            // add this to the bindings list
            _bindings.push_back( binding );
        }
        break;
    case ( EL_BIND ):
        {
            // EL_BIND, const char *, ..., NULL
            //      perform the BIND buildin command.  Refer to editrc(5) for more information.

            const char *name = (const char*) GETARG( 1 );

            for ( int i=0; i<_bindings.size(); i++ )
            {
                el_binding *bind = _bindings[i];
                if ( strcmp( bind->name, name ) == 0 )
                {
                    bind->key = (const char *) GETARG( 0 );
                    break;
                }
            }

        }
        break;
    case ( EL_CLIENTDATA ):
        {
            clientData = GETARG( 0 );
        }
        break;
    default:
        assert( !"Not Implemented!" );
    }
    return 0;
}

void
el_end (EditLine *el)
{
    assert( !"Not implemented!" );
}

void
el_reset (EditLine *)
{
    assert( !"Not implemented!" );
}

int
el_getc (EditLine *, char *)
{
    assert( !"Not implemented!" );
    return 0;
}

void
el_push (EditLine *, char *)
{
    assert( !"Not implemented!" );
}

void
el_beep (EditLine *)
{
    Beep( 1000, 500 );
}

int
el_parse (EditLine *, int, const char **)
{
    assert( !"Not implemented!" );
    return 0;
}

int
el_get (EditLine *el, int code, ...)
{
    switch ( code )
    {
    case ( EL_CLIENTDATA ):
        {
            void **dout = (void**) GETARG( 0 );
            *dout = clientData;
        }
        break;
    default:
        assert( !"Not implemented!" );
    }
    return 0;
}

int
el_source (EditLine *el, const char *file)
{
    // init edit line by reading the contents of 'file'
    // nothing to do here on windows...
    return 0;
}

void
el_resize (EditLine *)
{
    assert( !"Not implemented!" );
}

const LineInfo *
el_line (EditLine *el)
{
    assert( !"Not implemented!" );
    return 0;
}

int
el_insertstr (EditLine *, const char *)
{
    assert( !"Not implemented!" );
    return 0;
}

void
el_deletestr (EditLine *, int)
{
    assert( !"Not implemented!" );
}

History *
history_init (void)
{
    // return dummy handle
    return (History*) -1;
}

void
history_end (History *)
{
    assert( !"Not implemented!" );
}

int
history (History *, HistEvent *, int op, ...)
{
    // perform operation 'op' on the history list with optional argumetns as needed by
    // the operation.
    return 0;
}

#endif