/** \file builtin_commandline.c Functions defining the commandline builtin

Functions used for implementing the commandline builtin.

*/
#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <wchar.h>
#include <wctype.h>
#include <sys/types.h>
#include <termios.h>
#include <signal.h>

#include "fallback.h"
#include "util.h"

#include "wutil.h"
#include "builtin.h"
#include "common.h"
#include "wgetopt.h"
#include "reader.h"
#include "proc.h"
#include "parser.h"
#include "tokenizer.h"
#include "input_common.h"
#include "input.h"

#include "parse_util.h"

/**
   Which part of the comandbuffer are we operating on
*/
enum
{
    STRING_MODE=1, /**< Operate on entire buffer */
    JOB_MODE, /**< Operate on job under cursor */
    PROCESS_MODE, /**< Operate on process under cursor */
    TOKEN_MODE /**< Operate on token under cursor */
}
;

/**
   For text insertion, how should it be done
*/
enum
{
    REPLACE_MODE=1, /**< Replace current text */
    INSERT_MODE, /**< Insert at cursor position */
    APPEND_MODE /**< Insert at end of current token/command/buffer */
}
;

/**
   Pointer to what the commandline builtin considers to be the current
   contents of the command line buffer.
 */
static const wchar_t *current_buffer=0;
/**
   What the commandline builtin considers to be the current cursor
   position.
 */
static size_t current_cursor_pos = (size_t)(-1);

/**
   Returns the current commandline buffer.
*/
static const wchar_t *get_buffer()
{
    return current_buffer;
}

/**
   Returns the position of the cursor
*/
static size_t get_cursor_pos()
{
    return current_cursor_pos;
}

static pthread_mutex_t transient_commandline_lock = PTHREAD_MUTEX_INITIALIZER;
static wcstring_list_t *get_transient_stack()
{
    ASSERT_IS_MAIN_THREAD();
    ASSERT_IS_LOCKED(transient_commandline_lock);
    // A pointer is a little more efficient than an object as a static because we can elide the thread-safe initialization
    static wcstring_list_t *result = NULL;
    if (! result)
    {
        result = new wcstring_list_t();
    }
    return result;
}

static bool get_top_transient(wcstring *out_result)
{
    ASSERT_IS_MAIN_THREAD();
    bool result = false;
    scoped_lock locker(transient_commandline_lock);
    const wcstring_list_t *stack = get_transient_stack();
    if (! stack->empty())
    {
        out_result->assign(stack->back());
        result = true;
    }
    return result;
}

builtin_commandline_scoped_transient_t::builtin_commandline_scoped_transient_t(const wcstring &cmd)
{
    ASSERT_IS_MAIN_THREAD();
    scoped_lock locker(transient_commandline_lock);
    wcstring_list_t *stack = get_transient_stack();
    stack->push_back(cmd);
    this->token = stack->size();
}

builtin_commandline_scoped_transient_t::~builtin_commandline_scoped_transient_t()
{
    ASSERT_IS_MAIN_THREAD();
    scoped_lock locker(transient_commandline_lock);
    wcstring_list_t *stack = get_transient_stack();
    assert(this->token == stack->size());
    stack->pop_back();
}

/**
   Replace/append/insert the selection with/at/after the specified string.

   \param begin beginning of selection
   \param end end of selection
   \param insert the string to insert
   \param append_mode can be one of REPLACE_MODE, INSERT_MODE or APPEND_MODE, affects the way the test update is performed
*/
static void replace_part(const wchar_t *begin,
                         const wchar_t *end,
                         const wchar_t *insert,
                         int append_mode)
{
    const wchar_t *buff = get_buffer();
    size_t out_pos = get_cursor_pos();

    wcstring out;

    out.append(buff, begin - buff);

    switch (append_mode)
    {
        case REPLACE_MODE:
        {

            out.append(insert);
            out_pos = wcslen(insert) + (begin-buff);
            break;

        }
        case APPEND_MODE:
        {
            out.append(begin, end-begin);
            out.append(insert);
            break;
        }
        case INSERT_MODE:
        {
            long cursor = get_cursor_pos() -(begin-buff);
            out.append(begin, cursor);
            out.append(insert);
            out.append(begin+cursor, end-begin-cursor);
            out_pos +=  wcslen(insert);
            break;
        }
    }
    out.append(end);
    reader_set_buffer(out, out_pos);
}

/**
   Output the specified selection.

   \param begin start of selection
   \param end  end of selection
   \param cut_at_cursor whether printing should stop at the surrent cursor position
   \param tokenize whether the string should be tokenized, printing one string token on every line and skipping non-string tokens
*/
static void write_part(const wchar_t *begin,
                       const wchar_t *end,
                       int cut_at_cursor,
                       int tokenize)
{
    size_t pos = get_cursor_pos()-(begin-get_buffer());

    if (tokenize)
    {
        wchar_t *buff = wcsndup(begin, end-begin);
//    fwprintf( stderr, L"Subshell: %ls, end char %lc\n", buff, *end );
        wcstring out;
        tokenizer_t tok(buff, TOK_ACCEPT_UNFINISHED);
        for (; tok_has_next(&tok); tok_next(&tok))
        {
            if ((cut_at_cursor) &&
                    (tok_get_pos(&tok)+wcslen(tok_last(&tok)) >= pos))
                break;

            switch (tok_last_type(&tok))
            {
                case TOK_STRING:
                {
                    out.append(escape_string(tok_last(&tok), UNESCAPE_INCOMPLETE));
                    out.push_back(L'\n');
                    break;
                }

                default:
                {
                    break;
                }
            }
        }

        stdout_buffer.append(out);

        free(buff);
    }
    else
    {
        if (cut_at_cursor)
        {
            end = begin+pos;
        }

//    debug( 0, L"woot2 %ls -> %ls", buff, esc );

        stdout_buffer.append(begin, end - begin);
        stdout_buffer.append(L"\n");

    }
}


/**
   The commandline builtin. It is used for specifying a new value for
   the commandline.
*/
static int builtin_commandline(parser_t &parser, wchar_t **argv)
{

    int buffer_part=0;
    int cut_at_cursor=0;

    int argc = builtin_count_args(argv);
    int append_mode=0;

    int function_mode = 0;
    int selection_mode = 0;

    int tokenize = 0;

    int cursor_mode = 0;
    int line_mode = 0;
    int search_mode = 0;
    int paging_mode = 0;
    const wchar_t *begin = NULL, *end = NULL;
    
    scoped_push<const wchar_t *> saved_current_buffer(&current_buffer);
    scoped_push<size_t> saved_current_cursor_pos(&current_cursor_pos);
    
    wcstring transient_commandline;
    if (get_top_transient(&transient_commandline))
    {
        current_buffer = transient_commandline.c_str();
        current_cursor_pos = transient_commandline.size();
    }
    else
    {
        current_buffer = reader_get_buffer();
        current_cursor_pos = reader_get_cursor_pos();
    }

    if (!get_buffer())
    {
        if (is_interactive_session)
        {
            /*
              Prompt change requested while we don't have
              a prompt, most probably while reading the
              init files. Just ignore it.
            */
            return 1;
        }

        stderr_buffer.append(argv[0]);
        stderr_buffer.append(L": Can not set commandline in non-interactive mode\n");
        builtin_print_help(parser, argv[0], stderr_buffer);
        return 1;
    }

    woptind=0;

    while (1)
    {
        static const struct woption
                long_options[] =
        {
            { L"append", no_argument, 0, 'a' },
            { L"insert", no_argument, 0, 'i' },
            { L"replace", no_argument, 0, 'r' },
            { L"current-job", no_argument, 0, 'j' },
            { L"current-process", no_argument, 0, 'p' },
            { L"current-token", no_argument, 0, 't' },
            { L"current-buffer", no_argument, 0, 'b' },
            { L"cut-at-cursor", no_argument, 0, 'c' },
            { L"function", no_argument, 0, 'f' },
            { L"tokenize", no_argument, 0, 'o' },
            { L"help", no_argument, 0, 'h' },
            { L"input", required_argument, 0, 'I' },
            { L"cursor", no_argument, 0, 'C' },
            { L"line", no_argument, 0, 'L' },
            { L"search-mode", no_argument, 0, 'S' },
            { L"selection", no_argument, 0, 's' },
            { L"paging-mode", no_argument, 0, 'P' },
            { 0, 0, 0, 0 }
        };

        int opt_index = 0;

        int opt = wgetopt_long(argc,
                               argv,
                               L"abijpctwforhI:CLSs",
                               long_options,
                               &opt_index);
        if (opt == -1)
            break;

        switch (opt)
        {
            case 0:
                if (long_options[opt_index].flag != 0)
                    break;
                append_format(stderr_buffer,
                              BUILTIN_ERR_UNKNOWN,
                              argv[0],
                              long_options[opt_index].name);
                builtin_print_help(parser, argv[0], stderr_buffer);

                return 1;

            case L'a':
                append_mode = APPEND_MODE;
                break;

            case L'b':
                buffer_part = STRING_MODE;
                break;


            case L'i':
                append_mode = INSERT_MODE;
                break;

            case L'r':
                append_mode = REPLACE_MODE;
                break;

            case 'c':
                cut_at_cursor=1;
                break;

            case 't':
                buffer_part = TOKEN_MODE;
                break;

            case 'j':
                buffer_part = JOB_MODE;
                break;

            case 'p':
                buffer_part = PROCESS_MODE;
                break;

            case 'f':
                function_mode=1;
                break;

            case 'o':
                tokenize=1;
                break;

            case 'I':
                current_buffer = woptarg;
                current_cursor_pos = wcslen(woptarg);
                break;

            case 'C':
                cursor_mode = 1;
                break;

            case 'L':
                line_mode = 1;
                break;

            case 'S':
                search_mode = 1;
                break;

            case 's':
                selection_mode = 1;
                break;

            case 'P':
                paging_mode = 1;
                break;

            case 'h':
                builtin_print_help(parser, argv[0], stdout_buffer);
                return 0;

            case L'?':
                builtin_unknown_option(parser, argv[0], argv[woptind-1]);
                return 1;
        }
    }

    if (function_mode)
    {
        int i;

        /*
          Check for invalid switch combinations
        */
        if (buffer_part || cut_at_cursor || append_mode || tokenize || cursor_mode || line_mode || search_mode || paging_mode)
        {
            append_format(stderr_buffer,
                          BUILTIN_ERR_COMBO,
                          argv[0]);

            builtin_print_help(parser, argv[0], stderr_buffer);
            return 1;
        }


        if (argc == woptind)
        {
            append_format(stderr_buffer,
                          BUILTIN_ERR_MISSING,
                          argv[0]);

            builtin_print_help(parser, argv[0], stderr_buffer);
            return 1;
        }
        for (i=woptind; i<argc; i++)
        {
            wchar_t c = input_function_get_code(argv[i]);
            if (c != (wchar_t)(-1))
            {
                /*
                  input_unreadch inserts the specified keypress or
                  readline function at the top of the stack of unused
                  keypresses
                */
                input_unreadch(c);
            }
            else
            {
                append_format(stderr_buffer,
                              _(L"%ls: Unknown input function '%ls'\n"),
                              argv[0],
                              argv[i]);
                builtin_print_help(parser, argv[0], stderr_buffer);
                return 1;
            }
        }

        return 0;
    }

    if (selection_mode)
    {
        size_t start, len;
        const wchar_t *buffer = reader_get_buffer();
        if (reader_get_selection(&start, &len))
        {
            wchar_t *selection = new wchar_t[len + 1];
            selection[len] = L'\0';
            selection = wcsncpy(selection, buffer + start, len);

            append_format(stdout_buffer, selection);
            delete selection;
        }
        else
        {
            append_format(stdout_buffer, L"");
        }
        return 0;
    }

    /*
      Check for invalid switch combinations
    */
    if ((search_mode || line_mode || cursor_mode || paging_mode) && (argc-woptind > 1))
    {

        append_format(stderr_buffer,
                      argv[0],
                      L": Too many arguments\n",
                      NULL);
        builtin_print_help(parser, argv[0], stderr_buffer);
        return 1;
    }

    if ((buffer_part || tokenize || cut_at_cursor) && (cursor_mode || line_mode || search_mode || paging_mode))
    {
        append_format(stderr_buffer,
                      BUILTIN_ERR_COMBO,
                      argv[0]);

        builtin_print_help(parser, argv[0], stderr_buffer);
        return 1;
    }


    if ((tokenize || cut_at_cursor) && (argc-woptind))
    {
        append_format(stderr_buffer,
                      BUILTIN_ERR_COMBO2,
                      argv[0],
                      L"--cut-at-cursor and --tokenize can not be used when setting the commandline");


        builtin_print_help(parser, argv[0], stderr_buffer);
        return 1;
    }

    if (append_mode && !(argc-woptind))
    {
        append_format(stderr_buffer,
                      BUILTIN_ERR_COMBO2,
                      argv[0],
                      L"insertion mode switches can not be used when not in insertion mode");

        builtin_print_help(parser, argv[0], stderr_buffer);
        return 1;
    }

    /*
      Set default modes
    */
    if (!append_mode)
    {
        append_mode = REPLACE_MODE;
    }

    if (!buffer_part)
    {
        buffer_part = STRING_MODE;
    }

    if (cursor_mode)
    {
        if (argc-woptind)
        {
            wchar_t *endptr;
            long new_pos;
            errno = 0;

            new_pos = wcstol(argv[woptind], &endptr, 10);
            if (*endptr || errno)
            {
                append_format(stderr_buffer,
                              BUILTIN_ERR_NOT_NUMBER,
                              argv[0],
                              argv[woptind]);
                builtin_print_help(parser, argv[0], stderr_buffer);
            }

            current_buffer = reader_get_buffer();
            new_pos = maxi(0L, mini(new_pos, (long)wcslen(current_buffer)));
            reader_set_buffer(current_buffer, (size_t)new_pos);
            return 0;
        }
        else
        {
            append_format(stdout_buffer, L"%lu\n", (unsigned long)reader_get_cursor_pos());
            return 0;
        }

    }

    if (line_mode)
    {
        size_t pos = reader_get_cursor_pos();
        const wchar_t *buff = reader_get_buffer();
        append_format(stdout_buffer, L"%lu\n", (unsigned long)parse_util_lineno(buff, pos));
        return 0;

    }

    if (search_mode)
    {
        return ! reader_search_mode();
    }

    if (paging_mode)
    {
        return ! reader_has_pager_contents();
    }


    switch (buffer_part)
    {
        case STRING_MODE:
        {
            begin = get_buffer();
            end = begin+wcslen(begin);
            break;
        }

        case PROCESS_MODE:
        {
            parse_util_process_extent(get_buffer(),
                                      get_cursor_pos(),
                                      &begin,
                                      &end);
            break;
        }

        case JOB_MODE:
        {
            parse_util_job_extent(get_buffer(),
                                  get_cursor_pos(),
                                  &begin,
                                  &end);
            break;
        }

        case TOKEN_MODE:
        {
            parse_util_token_extent(get_buffer(),
                                    get_cursor_pos(),
                                    &begin,
                                    &end,
                                    0, 0);
            break;
        }

    }

    switch (argc-woptind)
    {
        case 0:
        {
            write_part(begin, end, cut_at_cursor, tokenize);
            break;
        }

        case 1:
        {
            replace_part(begin, end, argv[woptind], append_mode);
            break;
        }

        default:
        {
            wcstring sb = argv[woptind];
            int i;

            for (i=woptind+1; i<argc; i++)
            {
                sb.push_back(L'\n');
                sb.append(argv[i]);
            }

            replace_part(begin, end, sb.c_str(), append_mode);

            break;
        }
    }

    return 0;
}