/*
 * vim:ts=4:sw=4:expandtab
 *
 * i3 - an improved dynamic tiling window manager
 *
 * © 2009-2011 Michael Stapelberg and contributors
 *
 * See file LICENSE for license information.
 *
 * i3-nagbar is a utility which displays a nag message.
 *
 */
#include <ev.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <stdbool.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <err.h>
#include <stdint.h>
#include <getopt.h>
#include <limits.h>

#include <xcb/xcb.h>
#include <xcb/xcb_aux.h>
#include <xcb/xcb_event.h>

#include "i3-nagbar.h"

typedef struct {
    char *label;
    char *action;
    int16_t x;
    uint16_t width;
} button_t;

static xcb_window_t win;
static xcb_pixmap_t pixmap;
static xcb_gcontext_t pixmap_gc;
static xcb_rectangle_t rect = { 0, 0, 600, 20 };
static char *glyphs_ucs[512];
static int input_position;
static int font_height;
static char *prompt = "You have an error in your i3 config file!";
static button_t *buttons;
static int buttoncnt;
xcb_window_t root;

/*
 * Starts the given application by passing it through a shell. We use double fork
 * to avoid zombie processes. As the started application’s parent exits (immediately),
 * the application is reparented to init (process-id 1), which correctly handles
 * childs, so we don’t have to do it :-).
 *
 * The shell is determined by looking for the SHELL environment variable. If it
 * does not exist, /bin/sh is used.
 *
 */
static void start_application(const char *command) {
    printf("executing: %s\n", command);
    if (fork() == 0) {
        /* Child process */
        setsid();
        if (fork() == 0) {
            /* Stores the path of the shell */
            static const char *shell = NULL;

            if (shell == NULL)
                if ((shell = getenv("SHELL")) == NULL)
                    shell = "/bin/sh";

            /* This is the child */
            execl(shell, shell, "-c", command, (void*)NULL);
            /* not reached */
        }
        exit(0);
    }
    wait(0);
}

static button_t *get_button_at(int16_t x, int16_t y) {
    for (int c = 0; c < buttoncnt; c++)
        if (x >= (buttons[c].x) && x <= (buttons[c].x + buttons[c].width))
            return &buttons[c];

    return NULL;
}

static void handle_button_press(xcb_connection_t *conn, xcb_button_press_event_t *event) {
    printf("button pressed on x = %d, y = %d\n",
            event->event_x, event->event_y);
    /* TODO: set a flag for the button, re-render */
}

/*
 * Called when the user releases the mouse button. Checks whether the
 * coordinates are over a button and executes the appropriate action.
 *
 */
static void handle_button_release(xcb_connection_t *conn, xcb_button_release_event_t *event) {
    printf("button released on x = %d, y = %d\n",
            event->event_x, event->event_y);
    /* If the user hits the close button, we exit(0) */
    if (event->event_x >= (rect.width - 32))
        exit(0);
    button_t *button = get_button_at(event->event_x, event->event_y);
    if (!button)
        return;
    start_application(button->action);

    /* TODO: unset flag, re-render */
}

/*
 * Handles expose events (redraws of the window) and rendering in general. Will
 * be called from the code with event == NULL or from X with event != NULL.
 *
 */
static int handle_expose(xcb_connection_t *conn, xcb_expose_event_t *event) {
    printf("expose!\n");

    /* re-draw the background */
    xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FOREGROUND, get_colorpixel(conn, "#900000"));
    xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &rect);

    /* restore font color */
    uint32_t values[3];
    values[0] = get_colorpixel(conn, "#FFFFFF");
    values[1] = get_colorpixel(conn, "#900000");
    xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND | XCB_GC_BACKGROUND, values);
    xcb_image_text_8(conn, strlen(prompt), pixmap, pixmap_gc, 4 + 4/* X */,
                      font_height + 2 + 4 /* Y = baseline of font */, prompt);

    /* render close button */
    int line_width = 4;
    int w = 20;
    int y = rect.width;
    values[0] = get_colorpixel(conn, "#680a0a");
    values[1] = line_width;
    xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND | XCB_GC_LINE_WIDTH, values);

    xcb_rectangle_t close = { y - w - (2 * line_width), 0, w + (2 * line_width), rect.height };
    xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &close);

    xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FOREGROUND, get_colorpixel(conn, "#d92424"));
    xcb_point_t points[] = {
        { y - w - (2 * line_width), line_width / 2 },
        { y - (line_width / 2), line_width / 2 },
        { y - (line_width / 2), (rect.height - (line_width / 2)) - 2 },
        { y - w - (2 * line_width), (rect.height - (line_width / 2)) - 2 },
        { y - w - (2 * line_width), line_width / 2 }
    };
    xcb_poly_line(conn, XCB_COORD_MODE_ORIGIN, pixmap, pixmap_gc, 5, points);

    values[0] = get_colorpixel(conn, "#ffffff");
    values[1] = get_colorpixel(conn, "#680a0a");
    values[2] = 1;
    xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND | XCB_GC_BACKGROUND | XCB_GC_LINE_WIDTH, values);
    xcb_image_text_8(conn, strlen("x"), pixmap, pixmap_gc, y - w - line_width + (w / 2) - 4/* X */,
                      font_height + 2 + 4 - 1/* Y = baseline of font */, "X");
    y -= w;

    y -= 20;

    /* render custom buttons */
    line_width = 1;
    for (int c = 0; c < buttoncnt; c++) {
        /* TODO: make w = text extents of the label */
        w = 90;
        y -= 30;
        xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FOREGROUND, get_colorpixel(conn, "#680a0a"));
        close = (xcb_rectangle_t){ y - w - (2 * line_width), 2, w + (2 * line_width), rect.height - 6 };
        xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &close);

        xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FOREGROUND, get_colorpixel(conn, "#d92424"));
        buttons[c].x = y - w - (2 * line_width);
        buttons[c].width = w;
        xcb_point_t points2[] = {
            { y - w - (2 * line_width), (line_width / 2) + 2 },
            { y - (line_width / 2), (line_width / 2) + 2 },
            { y - (line_width / 2), (rect.height - 4 - (line_width / 2)) },
            { y - w - (2 * line_width), (rect.height - 4 - (line_width / 2)) },
            { y - w - (2 * line_width), (line_width / 2) + 2 }
        };
        xcb_poly_line(conn, XCB_COORD_MODE_ORIGIN, pixmap, pixmap_gc, 5, points2);

        values[0] = get_colorpixel(conn, "#ffffff");
        values[1] = get_colorpixel(conn, "#680a0a");
        xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND | XCB_GC_BACKGROUND, values);
        xcb_image_text_8(conn, strlen(buttons[c].label), pixmap, pixmap_gc, y - w - line_width + 6/* X */,
                          font_height + 2 + 3/* Y = baseline of font */, buttons[c].label);

        y -= w;
    }

    /* border line at the bottom */
    line_width = 2;
    values[0] = get_colorpixel(conn, "#470909");
    values[1] = line_width;
    xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND | XCB_GC_LINE_WIDTH, values);
    xcb_point_t bottom[] = {
        { 0, rect.height - 0 },
        { rect.width, rect.height - 0 }
    };
    xcb_poly_line(conn, XCB_COORD_MODE_ORIGIN, pixmap, pixmap_gc, 2, bottom);


    /* Copy the contents of the pixmap to the real window */
    xcb_copy_area(conn, pixmap, win, pixmap_gc, 0, 0, 0, 0, rect.width, rect.height);
    xcb_flush(conn);

    return 1;
}

int main(int argc, char *argv[]) {
    char *pattern = "-misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
    int o, option_index = 0;

    static struct option long_options[] = {
        {"version", no_argument, 0, 'v'},
        {"font", required_argument, 0, 'f'},
        {"button", required_argument, 0, 'b'},
        {"help", no_argument, 0, 'h'},
        {0, 0, 0, 0}
    };

    char *options_string = "b:f:vh";

    while ((o = getopt_long(argc, argv, options_string, long_options, &option_index)) != -1) {
        switch (o) {
            case 'v':
                printf("i3-nagbar " I3_VERSION);
                return 0;
            case 'f':
                FREE(pattern);
                pattern = strdup(optarg);
                break;
            case 'h':
                printf("i3-nagbar " I3_VERSION);
                printf("i3-nagbar [-s <socket>] [-p <prefix>] [-l <limit>] [-P <prompt>] [-f <font>] [-v]\n");
                return 0;
            case 'b':
                buttons = realloc(buttons, sizeof(button_t) * (buttoncnt + 1));
                buttons[buttoncnt].label = optarg;
                buttons[buttoncnt].action = argv[optind];
                printf("button with label *%s* and action *%s*\n",
                        buttons[buttoncnt].label,
                        buttons[buttoncnt].action);
                buttoncnt++;
                printf("now %d buttons\n", buttoncnt);
                if (optind < argc)
                    optind++;
                break;
        }
    }

    int screens;
    xcb_connection_t *conn = xcb_connect(NULL, &screens);
    if (xcb_connection_has_error(conn))
        die("Cannot open display\n");

    /* Place requests for the atoms we need as soon as possible */
    #define xmacro(atom) \
        xcb_intern_atom_cookie_t atom ## _cookie = xcb_intern_atom(conn, 0, strlen(#atom), #atom);
    #include "atoms.xmacro"
    #undef xmacro

    xcb_screen_t *root_screen = xcb_aux_get_screen(conn, screens);
    root = root_screen->root;

    uint32_t font_id = get_font_id(conn, pattern, &font_height);

    /* Open an input window */
    win = open_input_window(conn, 500, font_height + 8 + 8 /* 8px padding */);

    /* Setup NetWM atoms */
    #define xmacro(name) \
        do { \
            xcb_intern_atom_reply_t *reply = xcb_intern_atom_reply(conn, name ## _cookie, NULL); \
            if (!reply) \
                die("Could not get atom " # name "\n"); \
            \
            A_ ## name = reply->atom; \
            free(reply); \
        } while (0);
    #include "atoms.xmacro"
    #undef xmacro

    /* Set dock mode */
    xcb_void_cookie_t dock_cookie = xcb_change_property(conn,
        XCB_PROP_MODE_REPLACE,
        win,
        A__NET_WM_WINDOW_TYPE,
        A_ATOM,
        32,
        1,
        (unsigned char*) &A__NET_WM_WINDOW_TYPE_DOCK);

    /* Reserve some space at the top of the screen */
    struct {
        uint32_t left;
        uint32_t right;
        uint32_t top;
        uint32_t bottom;
        uint32_t left_start_y;
        uint32_t left_end_y;
        uint32_t right_start_y;
        uint32_t right_end_y;
        uint32_t top_start_x;
        uint32_t top_end_x;
        uint32_t bottom_start_x;
        uint32_t bottom_end_x;
    } __attribute__((__packed__)) strut_partial = {0,};

    strut_partial.top = font_height + 6;
    strut_partial.top_start_x = 0;
    strut_partial.top_end_x = 800;

    xcb_void_cookie_t strut_cookie = xcb_change_property(conn,
        XCB_PROP_MODE_REPLACE,
        win,
        A__NET_WM_STRUT_PARTIAL,
        A_CARDINAL,
        32,
        12,
        &strut_partial);

    /* Create pixmap */
    pixmap = xcb_generate_id(conn);
    pixmap_gc = xcb_generate_id(conn);
    xcb_create_pixmap(conn, root_screen->root_depth, pixmap, win, 500, font_height + 8);
    xcb_create_gc(conn, pixmap_gc, pixmap, 0, 0);

    /* Create graphics context */
    xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FONT, font_id);

    /* Grab the keyboard to get all input */
    xcb_flush(conn);

    xcb_generic_event_t *event;
    while ((event = xcb_wait_for_event(conn)) != NULL) {
        if (event->response_type == 0) {
            fprintf(stderr, "X11 Error received! sequence %x\n", event->sequence);
            continue;
        }

        /* Strip off the highest bit (set if the event is generated) */
        int type = (event->response_type & 0x7F);

        switch (type) {
            case XCB_EXPOSE:
                handle_expose(conn, (xcb_expose_event_t*)event);
                break;

            case XCB_BUTTON_PRESS:
                handle_button_press(conn, (xcb_button_press_event_t*)event);
                break;

            case XCB_BUTTON_RELEASE:
                handle_button_release(conn, (xcb_button_release_event_t*)event);
                break;

            case XCB_CONFIGURE_NOTIFY: {
                xcb_configure_notify_event_t *configure_notify = (xcb_configure_notify_event_t*)event;
                rect = (xcb_rectangle_t){
                    configure_notify->x,
                    configure_notify->y,
                    configure_notify->width,
                    configure_notify->height
                };

                /* Recreate the pixmap / gc */
                xcb_free_pixmap(conn, pixmap);
                xcb_free_gc(conn, pixmap_gc);

                xcb_create_pixmap(conn, root_screen->root_depth, pixmap, win, rect.width, rect.height);
                xcb_create_gc(conn, pixmap_gc, pixmap, 0, 0);

                /* Create graphics context */
                xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FONT, font_id);
                break;
            }
        }

        free(event);
    }

    return 0;
}