/*
   Internal file viewer for the Midnight Commander
   Interface functions

   Copyright (C) 1994-2023
   Free Software Foundation, Inc

   Written by:
   Miguel de Icaza, 1994, 1995, 1998
   Janne Kukonlehto, 1994, 1995
   Jakub Jelinek, 1995
   Joseph M. Hinkle, 1996
   Norbert Warmuth, 1997
   Pavel Machek, 1998
   Roland Illig <roland.illig@gmx.de>, 2004, 2005
   Slava Zanko <slavazanko@google.com>, 2009, 2013
   Andrew Borodin <aborodin@vmail.ru>, 2009-2022
   Ilia Maslakov <il.smind@gmail.com>, 2009

   This file is part of the Midnight Commander.

   The Midnight Commander is free software: you can redistribute it
   and/or modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation, either version 3 of the License,
   or (at your option) any later version.

   The Midnight Commander is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <errno.h>

#include "lib/global.h"
#include "lib/tty/tty.h"
#include "lib/vfs/vfs.h"
#include "lib/strutil.h"
#include "lib/util.h"           /* load_file_position() */
#include "lib/widget.h"

#include "src/filemanager/layout.h"
#include "src/filemanager/filemanager.h"        /* the_menubar */

#include "internal.h"

/*** global variables ****************************************************************************/

mcview_mode_flags_t mcview_global_flags = {
    .wrap = TRUE,
    .hex = FALSE,
    .magic = TRUE,
    .nroff = FALSE
};

mcview_mode_flags_t mcview_altered_flags = {
    .wrap = FALSE,
    .hex = FALSE,
    .magic = FALSE,
    .nroff = FALSE
};

gboolean mcview_remember_file_position = FALSE;

/* Maxlimit for skipping updates */
int mcview_max_dirt_limit = 10;

/* Scrolling is done in pages or line increments */
gboolean mcview_mouse_move_pages = TRUE;

/* end of file will be showen from mcview_show_eof */
char *mcview_show_eof = NULL;

/*** file scope macro definitions ****************************************************************/

/*** file scope type declarations ****************************************************************/

/*** forward declarations (file scope functions) *************************************************/

/*** file scope variables ************************************************************************/

/* --------------------------------------------------------------------------------------------- */
/*** file scope functions ************************************************************************/
/* --------------------------------------------------------------------------------------------- */

static void
mcview_mouse_callback (Widget * w, mouse_msg_t msg, mouse_event_t * event)
{
    WView *view = (WView *) w;
    const WRect *r = &view->data_area;
    gboolean ok = TRUE;

    switch (msg)
    {
    case MSG_MOUSE_DOWN:
        if (mcview_is_in_panel (view))
        {
            if (event->y == WIDGET (w->owner)->rect.y)
            {
                /* return MOU_UNHANDLED */
                event->result.abort = TRUE;
                /* don't draw viewer over menu */
                ok = FALSE;
                break;
            }

            if (!widget_get_state (w, WST_FOCUSED))
            {
                /* Grab focus */
                (void) change_panel ();
            }
        }
        MC_FALLTHROUGH;

    case MSG_MOUSE_CLICK:
        if (!view->mode_flags.wrap)
        {
            /* Scrolling left and right */
            int x;

            x = event->x + 1;   /* FIXME */

            if (x < r->cols * 1 / 4)
            {
                mcview_move_left (view, 1);
                event->result.repeat = msg == MSG_MOUSE_DOWN;
            }
            else if (x < r->cols * 3 / 4)
            {
                /* ignore the click */
                ok = FALSE;
            }
            else
            {
                mcview_move_right (view, 1);
                event->result.repeat = msg == MSG_MOUSE_DOWN;
            }
        }
        else
        {
            /* Scrolling up and down */
            int y;

            y = event->y + 1;   /* FIXME */

            if (y < r->y + r->lines * 1 / 3)
            {
                if (mcview_mouse_move_pages)
                    mcview_move_up (view, r->lines / 2);
                else
                    mcview_move_up (view, 1);

                event->result.repeat = msg == MSG_MOUSE_DOWN;
            }
            else if (y < r->y + r->lines * 2 / 3)
            {
                /* ignore the click */
                ok = FALSE;
            }
            else
            {
                if (mcview_mouse_move_pages)
                    mcview_move_down (view, r->lines / 2);
                else
                    mcview_move_down (view, 1);

                event->result.repeat = msg == MSG_MOUSE_DOWN;
            }
        }
        break;

    case MSG_MOUSE_SCROLL_UP:
        mcview_move_up (view, 2);
        break;

    case MSG_MOUSE_SCROLL_DOWN:
        mcview_move_down (view, 2);
        break;

    default:
        ok = FALSE;
        break;
    }

    if (ok)
        mcview_update (view);
}

/* --------------------------------------------------------------------------------------------- */
/*** public functions ****************************************************************************/
/* --------------------------------------------------------------------------------------------- */

WView *
mcview_new (int y, int x, int lines, int cols, gboolean is_panel)
{
    WRect r = { y, x, lines, cols };
    WView *view;
    Widget *w;

    view = g_new0 (WView, 1);
    w = WIDGET (view);

    widget_init (w, &r, mcview_callback, mcview_mouse_callback);
    w->options |= WOP_SELECTABLE | WOP_TOP_SELECT;
    w->keymap = viewer_map;

    mcview_clear_mode_flags (&view->mode_flags);
    view->hexedit_mode = FALSE;
    view->hex_keymap = viewer_hex_map;
    view->hexview_in_text = FALSE;
    view->locked = FALSE;

    view->dpy_frame_size = is_panel ? 1 : 0;
    view->converter = str_cnv_from_term;

    mcview_init (view);

    if (mcview_global_flags.hex)
        mcview_toggle_hex_mode (view);
    if (mcview_global_flags.nroff)
        mcview_toggle_nroff_mode (view);
    if (mcview_global_flags.wrap)
        mcview_toggle_wrap_mode (view);
    if (mcview_global_flags.magic)
        mcview_toggle_magic_mode (view);

    return view;
}

/* --------------------------------------------------------------------------------------------- */
/** Real view only */

gboolean
mcview_viewer (const char *command, const vfs_path_t * file_vpath, int start_line,
               off_t search_start, off_t search_end)
{
    gboolean succeeded;
    WView *lc_mcview;
    WDialog *view_dlg;
    Widget *vw, *b;
    WGroup *g;

    /* Create dialog and widgets, put them on the dialog */
    view_dlg = dlg_create (FALSE, 0, 0, 1, 1, WPOS_FULLSCREEN, FALSE, NULL, mcview_dialog_callback,
                           NULL, "[Internal File Viewer]", NULL);
    vw = WIDGET (view_dlg);
    widget_want_tab (vw, TRUE);

    g = GROUP (view_dlg);

    lc_mcview = mcview_new (vw->rect.y, vw->rect.x, vw->rect.lines - 1, vw->rect.cols, FALSE);
    group_add_widget_autopos (g, lc_mcview, WPOS_KEEP_ALL, NULL);

    b = WIDGET (buttonbar_new ());
    group_add_widget_autopos (g, b, b->pos_flags, NULL);

    view_dlg->get_title = mcview_get_title;

    succeeded =
        mcview_load (lc_mcview, command, vfs_path_as_str (file_vpath), start_line, search_start,
                     search_end);

    if (succeeded)
        dlg_run (view_dlg);
    else
        dlg_close (view_dlg);

    if (widget_get_state (vw, WST_CLOSED))
        widget_destroy (vw);

    return succeeded;
}

/* {{{ Miscellaneous functions }}} */

/* --------------------------------------------------------------------------------------------- */

gboolean
mcview_load (WView * view, const char *command, const char *file, int start_line,
             off_t search_start, off_t search_end)
{
    gboolean retval = FALSE;
    vfs_path_t *vpath = NULL;

    g_assert (view->bytes_per_line != 0);

    view->filename_vpath = vfs_path_from_str (file);

    /* get working dir */
    if (file != NULL && file[0] != '\0')
    {
        vfs_path_free (view->workdir_vpath, TRUE);

        if (!g_path_is_absolute (file))
        {
            vfs_path_t *p;

            p = vfs_path_clone (vfs_get_raw_current_dir ());
            view->workdir_vpath = vfs_path_append_new (p, file, (char *) NULL);
            vfs_path_free (p, TRUE);
        }
        else
        {
            /* try extract path from filename */
            const char *fname;
            char *dir;

            fname = x_basename (file);
            dir = g_strndup (file, (size_t) (fname - file));
            view->workdir_vpath = vfs_path_from_str (dir);
            g_free (dir);
        }
    }

    if (!mcview_is_in_panel (view))
        view->dpy_text_column = 0;

#ifdef HAVE_CHARSET
    mcview_set_codeset (view);
#endif

    if (command != NULL && (view->mode_flags.magic || file == NULL || file[0] == '\0'))
        retval = mcview_load_command_output (view, command);
    else if (file != NULL && file[0] != '\0')
    {
        int fd;
        char tmp[BUF_MEDIUM];
        struct stat st;

        /* Open the file */
        vpath = vfs_path_from_str (file);
        fd = mc_open (vpath, O_RDONLY | O_NONBLOCK);
        if (fd == -1)
        {
            g_snprintf (tmp, sizeof (tmp), _("Cannot open \"%s\"\n%s"),
                        file, unix_error_string (errno));
            mcview_close_datasource (view);
            mcview_show_error (view, tmp);
            vfs_path_free (view->filename_vpath, TRUE);
            view->filename_vpath = NULL;
            vfs_path_free (view->workdir_vpath, TRUE);
            view->workdir_vpath = NULL;
            goto finish;
        }

        /* Make sure we are working with a regular file */
        if (mc_fstat (fd, &st) == -1)
        {
            mc_close (fd);
            g_snprintf (tmp, sizeof (tmp), _("Cannot stat \"%s\"\n%s"),
                        file, unix_error_string (errno));
            mcview_close_datasource (view);
            mcview_show_error (view, tmp);
            vfs_path_free (view->filename_vpath, TRUE);
            view->filename_vpath = NULL;
            vfs_path_free (view->workdir_vpath, TRUE);
            view->workdir_vpath = NULL;
            goto finish;
        }

        if (!S_ISREG (st.st_mode))
        {
            mc_close (fd);
            mcview_close_datasource (view);
            mcview_show_error (view, _("Cannot view: not a regular file"));
            vfs_path_free (view->filename_vpath, TRUE);
            view->filename_vpath = NULL;
            vfs_path_free (view->workdir_vpath, TRUE);
            view->workdir_vpath = NULL;
            goto finish;
        }

        if (st.st_size == 0 || mc_lseek (fd, 0, SEEK_SET) == -1)
        {
            /* Must be one of those nice files that grow (/proc) */
            mcview_set_datasource_vfs_pipe (view, fd);
        }
        else
        {
            if (view->mode_flags.magic)
            {
                int type;

                type = get_compression_type (fd, file);

                if (type != COMPRESSION_NONE)
                {
                    char *tmp_filename;
                    vfs_path_t *vpath1;
                    int fd1;

                    tmp_filename = g_strconcat (file, decompress_extension (type), (char *) NULL);
                    vpath1 = vfs_path_from_str (tmp_filename);
                    g_free (tmp_filename);
                    fd1 = mc_open (vpath1, O_RDONLY | O_NONBLOCK);
                    vfs_path_free (vpath1, TRUE);

                    if (fd1 == -1)
                    {
                        g_snprintf (tmp, sizeof (tmp), _("Cannot open \"%s\" in parse mode\n%s"),
                                    file, unix_error_string (errno));
                        mcview_close_datasource (view);
                        mcview_show_error (view, tmp);
                    }
                    else
                    {
                        mc_close (fd);
                        fd = fd1;
                        mc_fstat (fd, &st);
                    }
                }
            }

            mcview_set_datasource_file (view, fd, &st);
        }
        retval = TRUE;
    }

  finish:
    view->command = g_strdup (command);
    view->dpy_start = 0;
    view->dpy_paragraph_skip_lines = 0;
    mcview_state_machine_init (&view->dpy_state_top, 0);
    view->dpy_wrap_dirty = FALSE;
    view->force_max = -1;
    view->dpy_text_column = 0;

    mcview_compute_areas (view);
    mcview_update_bytes_per_line (view);

    if (mcview_remember_file_position && view->filename_vpath != NULL && start_line == 0)
    {
        long line, col;
        off_t new_offset, max_offset;

        load_file_position (view->filename_vpath, &line, &col, &new_offset, &view->saved_bookmarks);
        max_offset = mcview_get_filesize (view) - 1;
        if (max_offset < 0)
            new_offset = 0;
        else
            new_offset = MIN (new_offset, max_offset);
        if (!view->mode_flags.hex)
        {
            view->dpy_start = mcview_bol (view, new_offset, 0);
            view->dpy_wrap_dirty = TRUE;
        }
        else
        {
            view->dpy_start = new_offset - new_offset % view->bytes_per_line;
            view->hex_cursor = new_offset;
        }
    }
    else if (start_line > 0)
        mcview_moveto (view, start_line - 1, 0);

    view->search_start = search_start;
    view->search_end = search_end;
    view->hexedit_lownibble = FALSE;
    view->hexview_in_text = FALSE;
    view->change_list = NULL;
    vfs_path_free (vpath, TRUE);
    return retval;
}

/* --------------------------------------------------------------------------------------------- */