#include <math.h>
#include <glib.h>
#include <glib-unix.h>
#include <time.h>
#include <unistd.h>
#include <sys/statvfs.h>
#include <locale.h>

#include "window.h"
#include "log.h"
#include "draw.h"
#include "connect.h"
#include "state.h"
#include "dwm.h"

#define EVEN(n) ((int)(n) - ((int)(n) % 2 != 0))

static void log_handler(const char *log_domain,
                        GLogLevelFlags level,
                        const char *message,
                        gpointer log_level)
{
    GLogLevelFlags message_level = level & G_LOG_LEVEL_MASK;

    if ((GLogLevelFlags)log_level < message_level)
        return;

    if (message_level <= G_LOG_LEVEL_WARNING)
        g_printerr("%s\n", message);
    else
        g_print("%s\n", message);
}


static gboolean mainloop_quit(gpointer data)
{
    g_main_loop_quit(data);
    return G_SOURCE_CONTINUE;
}

// Taken from slstatus
// XXX: Change with something more robust
char *cpu_percentage(void)
{
    static long double a[7];
    long double b[7], sum;
    memcpy(b, a, sizeof(b));

    FILE *stat = fopen("/proc/stat", "rb");
    g_assert_nonnull(stat);

    /* cpu user nice system idle iowait irq softirq */
    g_assert(7 == fscanf(stat, "%*s %Lf %Lf %Lf %Lf %Lf %Lf %Lf",
               &a[0], &a[1], &a[2], &a[3], &a[4], &a[5], &a[6]));

    fclose(stat);
    if (b[0] == 0) return NULL;

    sum = (b[0] + b[1] + b[2] + b[3] + b[4] + b[5] + b[6]) -
          (a[0] + a[1] + a[2] + a[3] + a[4] + a[5] + a[6]);

    if (sum == 0) return NULL;

    return g_strdup_printf("  %d%%", (int)(100 *
                           ((b[0] + b[1] + b[2] + b[5] + b[6]) -
                            (a[0] + a[1] + a[2] + a[5] + a[6])) / sum));
}

static gboolean cpu_update(Button *btn)
{
    char *perc = cpu_percentage();

    // Don't update on error
    if (perc == NULL)
        return G_SOURCE_CONTINUE;

    ButtonSimple *sbtn = CAST(btn, ButtonSimple);
    bool update = g_strcmp0(perc, sbtn->text) != 0;
    button_simple_set_text(btn, perc, sbtn->text_color);

    if (update)
        state_request_redraw(sbtn->data, false);

    return G_SOURCE_CONTINUE;
}

static gboolean ram_update(Button *btn)
{
    FILE *meminfo = fopen("/proc/meminfo", "rb");
    g_assert_nonnull(meminfo);

    uintmax_t total, unused, buffers, cached;
    g_assert(5 == fscanf(meminfo,
                         "MemTotal: %ju kB\n"
                         "MemFree: %ju kB\n"
                         "MemAvailable: %ju kB\n"
                         "Buffers: %ju kB\n"
                         "Cached: %ju kB\n",
                         &total, &unused, &buffers, &buffers, &cached));

    int usage = 100 * (total - unused - buffers - cached) / total;
    fclose(meminfo);


    ButtonSimple *sbtn = CAST(btn, ButtonSimple);
    char *ram = g_strdup_printf("  %d%%", usage);
    bool update = g_strcmp0(ram, sbtn->text) != 0;
    button_simple_set_text(btn, ram, sbtn->text_color);

    if (update)
        state_request_redraw(sbtn->data, false);

    return G_SOURCE_CONTINUE;
}

static gboolean temp_update(Button *btn)
{
    FILE *thermal = fopen("/sys/class/thermal/thermal_zone2/temp", "rb");
    g_assert_nonnull(thermal);

    uintmax_t value;
    g_assert(1 == fscanf(thermal, "%ju\n", &value));
    fclose(thermal);

    ButtonSimple *sbtn = CAST(btn, ButtonSimple);
    char *temp = g_strdup_printf(" %d °C", (int)(value / 1000));
    bool update = g_strcmp0(temp, sbtn->text) != 0;
    button_simple_set_text(btn, temp, sbtn->text_color);

    if (update)
        state_request_redraw(sbtn->data, false);

    return G_SOURCE_CONTINUE;
}

static gboolean disk_update(Button *btn)
{
    struct statvfs buffer;
    g_assert(statvfs("/", &buffer) == 0);
    const double used = 1.0 - ((double)buffer.f_bavail / (double)buffer.f_blocks);

    ButtonSimple *sbtn = CAST(btn, ButtonSimple);
    char *disk = g_strdup_printf("  %d%%", (int)round(used * 100.0));
    bool update = g_strcmp0(disk, sbtn->text) != 0;
    button_simple_set_text(btn, disk, sbtn->text_color);

    if (update)
        state_request_redraw(sbtn->data, false);

    return G_SOURCE_CONTINUE;
}

static gboolean date_update(Button *btn)
{
    GDateTime *dt = g_date_time_new_now_local();
    char *text = g_date_time_format(dt, "%A %d    %H:%M");
    g_date_time_unref(dt);

    g_assert_nonnull(text);
    button_simple_set_text(btn, text, CAST(btn, ButtonSimple)->text_color);

    struct {
        State *state;
        timer_t timer;
    } *date_ctx = CAST(btn, ButtonSimple)->data;

    log_debug("Updated date and time");
    state_request_redraw(date_ctx->state, false);

    struct timespec current;
    clock_gettime(CLOCK_REALTIME, &current);

    struct itimerspec its = { 0 };
    its.it_value.tv_sec = 60 - (current.tv_sec % 60);
    timer_settime(date_ctx->timer, 0, &its, NULL);

    return G_SOURCE_CONTINUE;
}

static void show_action(Button *btn)
{
    log_info("Called action: %s", button_simple_get_text(btn));
}

static void quit_action(Button *btn)
{
    log_info("Quit button pressed");
    g_main_loop_quit(CAST(btn, ButtonSimple)->data);
}

static void menu_action(Button *btn)
{
    struct {
        State *state;
        ButtonGroup *group;
        char *strings[2];
        GList *toggled;
        bool closed;
    } *menu_ctx = CAST(btn, ButtonSimple)->data;

    // NOTE: Clear the previous animation, if any
    g_list_free(menu_ctx->group->children);
    g_clear_pointer(&menu_ctx->group->btn.anim, animation_destroy);
    menu_ctx->group->children = g_list_copy(menu_ctx->toggled);

    char *text = g_strdup(menu_ctx->strings[menu_ctx->closed]);
    button_simple_set_text(btn, text, CAST(btn, ButtonSimple)->text_color);

    Animation *anim = menu_ctx->closed
        ? animation_group_grow_create(MILLIS(600))
        : animation_group_shrink_create(MILLIS(600));

    g_assert(button_set_animation((gpointer)menu_ctx->group, anim));
    state_request_animation(menu_ctx->state);

    log_debug("%s menu", menu_ctx->closed ? "Opened" : "Closed");
    menu_ctx->closed = !menu_ctx->closed;
}

static void register_buttons(State *state, Color color, Color text_color, Color line_color, int line_w)
{
    // Precompute max button size
    int text_w;
    draw_compute_text_size(state->draw, "  100%", &text_w, NULL);
    int min_w = text_w + line_w + state->draw->height;

    // Cpu usage button
    Button *cpu_btn = button_simple_create(PANGO_ALIGN_RIGHT, color);
    button_simple_set_text(cpu_btn, g_strdup("  0%"), text_color);
    button_simple_set_action(cpu_btn, show_action, state);
    button_set_line(cpu_btn, line_color, line_w);
    button_set_width(cpu_btn, 0, min_w);
    state_add_button(state, cpu_btn);

    cpu_update(cpu_btn);
    g_timeout_add(MILLIS(1), G_SOURCE_FUNC(cpu_update), cpu_btn);

    // Temperature button
    Button *temp_btn = button_simple_create(PANGO_ALIGN_RIGHT, color);
    button_simple_set_text(temp_btn, NULL, text_color);
    button_simple_set_action(temp_btn, show_action, state);
    button_set_line(temp_btn, line_color, line_w);
    button_set_width(temp_btn, 0, min_w);
    state_add_button(state, temp_btn);

    temp_update(temp_btn);
    g_timeout_add(MILLIS(20), G_SOURCE_FUNC(temp_update), temp_btn);

    // Ram usage button
    Button *ram_btn = button_simple_create(PANGO_ALIGN_RIGHT, color);
    button_simple_set_text(ram_btn, NULL, text_color);
    button_simple_set_action(ram_btn, show_action, state);
    button_set_line(ram_btn, line_color, line_w);
    button_set_width(ram_btn, 0, min_w);
    state_add_button(state, ram_btn);

    ram_update(ram_btn);
    g_timeout_add(MILLIS(10), G_SOURCE_FUNC(ram_update), ram_btn);

    // Disk usage button
    Button *disk_btn = button_simple_create(PANGO_ALIGN_RIGHT, color);
    button_simple_set_text(disk_btn, NULL, text_color);
    button_simple_set_action(disk_btn, show_action, state);
    button_set_line(disk_btn, line_color, line_w);
    button_set_width(disk_btn, 0, min_w);
    state_add_button(state, disk_btn);

    disk_update(disk_btn);
    g_timeout_add(MILLIS(60), G_SOURCE_FUNC(disk_update), disk_btn);
}

int main(int argc, char **argv)
{
    setlocale(LC_CTYPE, "");
    g_log_set_default_handler(log_handler, (gpointer)G_LOG_LEVEL_DEBUG);

    GMainLoop *mainloop = g_main_loop_new(NULL, FALSE);

    Connection *con = connect_create();

    Window *win = window_create(con);

    int screen_width = con->screen_size->width;
    int screen_height = con->screen_size->height;
    double scale = window_get_scale(win);

    int height = EVEN(round(screen_height * 0.021));
    int x_padding = EVEN(round(screen_width * 0.005));
    int y_padding = EVEN(round(screen_height * 0.004));

    log_debug("Calculated dimensions [height=%d, x_pad=%d, y_pad=%d]", height, x_padding, y_padding);

    Color background_all = { 0.3, 0.3, 0.3, 1 };
    PangoContext *context = pango_cairo_create_context(window_get_context(win));

    Drawer *draw = draw_create();
    draw_set_background(draw, background_all);
    draw_set_separator(draw, 10);
    draw_set_font(draw, "Hack 13 Bold");
    draw_set_context(draw, context);
    draw_set_size(draw, height, x_padding, x_padding, y_padding, scale);

    State *state = state_create(win, draw);

    Color color = { 0.4, 0.4, 0.4, 1 };
    Color purple = { 0.502, 0.168, 0.886, 1 };
    Color line_color = { 0.8, 0.8, 0.8, 1 };
    Color text_color = { 0.9, 0.9, 0.9, 1 };

    // Dwm tags
    DwmIpc *dwm = dwm_create(state, "/tmp/dwm.sock");
    dwm_register_tags(dwm, color, purple, text_color);

    int line_w = 0;
    register_buttons(state, color, text_color, line_color, line_w);

    // Buttons with special handling

    struct {
        State *state;
        timer_t timer;
    } date_ctx = { state, 0 };

    int text_w;
    draw_compute_text_size(state->draw, "Wednesday 31    12:34", &text_w, NULL);
    int min_w = text_w + line_w + state->draw->height;

    // Date & time button
    Button *date_btn = button_simple_create(PANGO_ALIGN_CENTER, color);
    button_simple_set_text(date_btn, NULL, text_color);
    button_simple_set_action(date_btn, NULL, &date_ctx);
    button_set_width(date_btn, 0, min_w);
    state_add_button(state, date_btn);

    struct sigevent sev = { 0 };
    sev.sigev_notify = SIGEV_SIGNAL;
    sev.sigev_signo = SIGUSR1;

    g_assert(timer_create(CLOCK_REALTIME, &sev, &date_ctx.timer) == 0);
    date_update(date_btn);

    // Quit button
    Button *q_btn = button_simple_create(PANGO_ALIGN_RIGHT, purple);
    button_simple_set_text(q_btn, g_strdup(""), text_color);
    button_simple_set_action(q_btn, quit_action, mainloop);
    state_add_button(state, q_btn);

    // Menu button(s)
    Color grey = { 0.5, 0.5, 0.5, 1 };
    Button *group = button_group_create(PANGO_ALIGN_LEFT, grey);

    Button *child1 = button_simple_create(PANGO_ALIGN_CENTER, color);
    button_set_padding(child1, 1, 1);
    button_simple_set_text(child1, g_strdup("C1"), text_color);
    button_simple_set_action(child1, show_action, NULL);

    Button *child2 = button_simple_create(PANGO_ALIGN_CENTER, color);
    button_set_padding(child2, 1, 1);
    button_simple_set_text(child2, g_strdup("C2"), text_color);
    button_simple_set_action(child2, show_action, NULL);

    Button *child3 = button_simple_create(PANGO_ALIGN_CENTER, color);
    button_set_padding(child3, 1, 1);
    button_simple_set_text(child3, g_strdup("C3"), text_color);
    button_simple_set_action(child3, show_action, NULL);

    struct {
        State *state;
        ButtonGroup *group;
        char *strings[2];
        GList *toggled;
        bool closed;
    } menu_ctx = { state, (gpointer)group, {"", ""}, NULL, true };

    Button *menu = button_simple_create(PANGO_ALIGN_LEFT, color);
    button_simple_set_text(menu, g_strdup(menu_ctx.strings[0]), text_color);
    button_simple_set_action(menu, menu_action, &menu_ctx);

    menu_ctx.toggled = g_list_append(menu_ctx.toggled, menu);
    menu_ctx.toggled = g_list_append(menu_ctx.toggled, child1);
    menu_ctx.toggled = g_list_append(menu_ctx.toggled, child2);
    menu_ctx.toggled = g_list_append(menu_ctx.toggled, child3);

    button_group_append(group, menu);
    state_add_button(state, group);

    state_order_button(state);

    connect_attach_state(con, state);
    connect_attach_source(con);

    guint source_alrm = g_unix_signal_add(SIGUSR1, G_SOURCE_FUNC(date_update), date_btn);
    guint source_term = g_unix_signal_add(SIGTERM, mainloop_quit, mainloop);
    guint source_int  = g_unix_signal_add(SIGINT,  mainloop_quit, mainloop);

    state_request_redraw(state, true);

    log_debug("Starting main loop");
    g_main_loop_run(mainloop);

    log_debug("Cleaning main loop");
    g_clear_pointer(&mainloop, g_main_loop_unref);

    g_source_remove(source_alrm);
    g_source_remove(source_term);
    g_source_remove(source_int);

    // NOTE: Skip the first element (the open/close button)
    if (menu_ctx.closed)
        g_list_free_full(g_list_delete_link(menu_ctx.toggled, menu_ctx.toggled), (GDestroyNotify)button_destroy);
    else
        g_list_free(menu_ctx.toggled);

    timer_delete(date_ctx.timer);
    g_object_unref(context);

    // NOTE: Buttons are freed by state_destroy
    dwm_destroy(dwm);
    state_destroy(state);
    draw_destroy(draw);
    window_destroy(win);
    connect_destroy(con);

    return 0;
}

// vim: ts=4 sw=4 et