/*
 * T.c
 * T is a lean Terminal emulator.
 *
 * This file is part of T.
 *
 * T 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.
 *
 * T 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
 * T. If not, see <http://www.gnu.org/licenses/>.
 */

#include <gdk/gdk.h>
#include <gdk/gdkkeysyms.h>
#include <gtk/gtk.h>
#include <unistd.h>
#include <vte/vte.h>
#include <stdlib.h>

#include "T.h"

static int window_count = 0;

/* Event callbacks */
static void window_destroy_callback(GtkWidget *widget, gpointer data);
static gboolean key_press_callback(GtkWidget *widget, GdkEvent *event, gpointer data);
static void terminal_child_exited_callback(VteTerminal *terminal, gpointer data);
static void terminal_window_title_changed_callback(VteTerminal *terminal, gpointer data);

/* Helper functions */
static void change_font_size(VteTerminal *terminal, int delta);
static void set_preferences(VteTerminal *terminal);
static void setup_terminal(GtkWindow *window, VteTerminal *terminal);

static void
window_destroy_callback(GtkWidget *widget, gpointer data)
{
    /* Keeping track of the open windows */
    window_count--;
}

static gboolean
key_press_callback(GtkWidget *widget, GdkEvent *event, gpointer data)
{
    GdkEventKey *key_event = (GdkEventKey *) event;
    VteTerminal *terminal = VTE_TERMINAL(widget);

    gboolean has_shift = (key_event->state & GDK_SHIFT_MASK) != 0;
    gboolean has_control = (key_event->state & GDK_CONTROL_MASK) != 0;

    if (!has_control)
        return FALSE;

    switch (key_event->keyval) {
    case GDK_KEY_minus:
        change_font_size(terminal, -1);
        return TRUE;
    case GDK_KEY_plus:
        change_font_size(terminal, 1);
        return TRUE;
    }

    if (!has_shift)
        return FALSE;

    /* Handles ctrl + shift + {c,v,n} */
    switch (key_event->keyval) {
    case GDK_KEY_C:
    case GDK_KEY_c:
        /* turn this event into a Control+Insert and delegate it */
        key_event->keyval = GDK_KEY_Insert;
        key_event->state &= ~GDK_SHIFT_MASK;
        break;
    case GDK_KEY_V:
    case GDK_KEY_v:
        /* turn this event into a Shift+Insert and delegate it */
        key_event->keyval = GDK_KEY_Insert;
        key_event->state &= ~GDK_CONTROL_MASK;
        break;
    case GDK_KEY_N:
    case GDK_KEY_n:
        new_window();
        return TRUE;
    }

    return FALSE;
}

static void
terminal_child_exited_callback(VteTerminal *terminal, gpointer data)
{
    /* The forked process exited; issue destruction of the terminal window */
    gtk_widget_destroy(GTK_WIDGET(GTK_WINDOW(data)));
}

static void
terminal_window_title_changed_callback(VteTerminal *terminal, gpointer data)
{
    GtkWindow *window = GTK_WINDOW(data);
    gtk_window_set_title(window, vte_terminal_get_window_title(terminal));
}

static void
change_font_size(VteTerminal *terminal, int delta)
{
    PangoFontDescription *desc = (PangoFontDescription *) vte_terminal_get_font(terminal);
    gint font_size = pango_font_description_get_size(desc) + delta * PANGO_SCALE;
    pango_font_description_set_size(desc, font_size);
    vte_terminal_set_font(terminal, desc);
}

static void
set_preferences(VteTerminal *terminal)
{
    /*
     * Options set here can (and should) be configured in config.h
     */

    /*
     * These are static because this function is called every time a new window
     * is created and we don't want to parse the colors all over again
     */
    static gboolean colors_parsed = FALSE;
    static GdkColor palette[CONFIG_PALETTE_SIZE], bg_color, fg_color;
    static const char *CONFIG_COLOR_PALETTE[CONFIG_PALETTE_SIZE] = {
        CONFIG_PALLETE_0,
        CONFIG_PALLETE_1,
        CONFIG_PALLETE_2,
        CONFIG_PALLETE_3,
        CONFIG_PALLETE_4,
        CONFIG_PALLETE_5,
        CONFIG_PALLETE_6,
        CONFIG_PALLETE_7,
        CONFIG_PALLETE_8,
        CONFIG_PALLETE_9,
        CONFIG_PALLETE_10,
        CONFIG_PALLETE_11,
        CONFIG_PALLETE_12,
        CONFIG_PALLETE_13,
        CONFIG_PALLETE_14,
        CONFIG_PALLETE_15,
    };

    if (!colors_parsed) {
        int i;

        gdk_color_parse(CONFIG_FOREGROUND_COLOR, &fg_color);
        gdk_color_parse(CONFIG_BACKGROUND_COLOR, &bg_color);
        for (i = 0; i < CONFIG_PALETTE_SIZE; ++i)
            gdk_color_parse(CONFIG_COLOR_PALETTE[i], &palette[i]);

        colors_parsed = TRUE;
    }

    /* Set preferences */
    vte_terminal_set_audible_bell(terminal, CONFIG_AUDIBLE_BELL);
    vte_terminal_set_colors(terminal, &fg_color, &bg_color, palette, CONFIG_PALETTE_SIZE);
    vte_terminal_set_cursor_blink_mode(terminal, CONFIG_CURSOR_BLINK_MODE);
    vte_terminal_set_font_from_string(terminal, CONFIG_FONT_NAME);
    vte_terminal_set_mouse_autohide(terminal, CONFIG_MOUSE_AUTOHIDE);
    vte_terminal_set_scrollback_lines(terminal, CONFIG_SCROLLBACK_LINES);
    vte_terminal_set_visible_bell(terminal, CONFIG_VISIBLE_BELL);
}

static void
setup_terminal(GtkWindow *window, VteTerminal *terminal)
{
    char *argv[] = { vte_get_user_shell(), NULL };
    GPid child_pid;

    vte_terminal_fork_command_full(terminal,
            VTE_PTY_DEFAULT,
            NULL, /* wd; NULL for cwd */
            argv, /* the program to fork into and its args */
            NULL, /* env vars */
            G_SPAWN_DO_NOT_REAP_CHILD,
            NULL, /* setup func */
            NULL, /* custom data to setup func */
            &child_pid,
            NULL); /* TODO: error handling */

    g_signal_connect(terminal, "child-exited", G_CALLBACK(terminal_child_exited_callback), window);
    g_signal_connect(terminal, "key-press-event", G_CALLBACK(key_press_callback), window);
    g_signal_connect(terminal, "window-title-changed", G_CALLBACK(terminal_window_title_changed_callback), window);

    set_preferences(terminal);
}

int
num_open_windows()
{
    return window_count;
}

void
new_window()
{
    GtkWindow *window = (GtkWindow *) gtk_window_new(GTK_WINDOW_TOPLEVEL);
    VteTerminal *terminal = (VteTerminal *) vte_terminal_new();
    setup_terminal(window, terminal);

    GdkGeometry hints;
    hints.base_width  = vte_terminal_get_char_width(terminal);
    hints.base_height = vte_terminal_get_char_height(terminal);
    hints.min_width   = hints.base_width * CONFIG_MIN_WIDTH;
    hints.min_height  = hints.base_height * CONFIG_MIN_HEIGHT;
    hints.width_inc   = hints.base_width;
    hints.height_inc  = hints.base_height;
    gtk_window_set_geometry_hints(window, GTK_WIDGET(terminal), &hints, GDK_HINT_RESIZE_INC | GDK_HINT_MIN_SIZE | GDK_HINT_BASE_SIZE);
    gtk_window_set_icon_name(window, "utilities-terminal");

    g_signal_connect(window, "delete-event", G_CALLBACK(gtk_false), NULL);
    g_signal_connect(window, "destroy", G_CALLBACK(window_destroy_callback), NULL);

    gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(terminal));

    gtk_widget_show(GTK_WIDGET(terminal));
    gtk_widget_show(GTK_WIDGET(window));

    window_count++;
}

void
wrn(const char *message)
{
    fprintf(stderr, "%s: %s\n", PROGRAM_NAME, message);
}

void
err(const char *message, int ecode)
{
    wrn(message);
    exit(ecode);
}