#include <gtk/gtk.h>
#include <cairo.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#define MAX_STUDENTS 1024
#define MAX_NAME 256

typedef struct {
    char name[MAX_NAME];
    int votes;
} Student;

static GtkWidget *text_input;
static GtkWidget *text_output;
static GtkWidget *drawing_area;

static Student chart_students[MAX_STUDENTS];
static int chart_count = 0;

static const double bar_colors[][3] = {
    {0.96, 0.76, 0.05},
    {0.75, 0.75, 0.75},
    {0.80, 0.50, 0.20},
    {0.26, 0.53, 0.96},
    {0.20, 0.78, 0.35},
    {0.90, 0.30, 0.30},
    {0.60, 0.20, 0.80},
    {0.10, 0.70, 0.80},
};
#define NUM_COLORS 8

static int find_student(Student *students, int count, const char *name) {
    for (int i = 0; i < count; i++)
        if (strcmp(students[i].name, name) == 0) return i;
    return -1;
}

static int cmp(const void *a, const void *b) {
    const Student *sa = (const Student *)a;
    const Student *sb = (const Student *)b;
    if (sb->votes != sa->votes) return sb->votes - sa->votes;
    return strcmp(sa->name, sb->name);
}

static void set_output(const char *text) {
    GtkTextBuffer *buf = gtk_text_view_get_buffer(GTK_TEXT_VIEW(text_output));
    gtk_text_buffer_set_text(buf, text, -1);
}

static gboolean on_draw(GtkWidget *widget, cairo_t *cr, gpointer data) {
    (void)data;
    int width  = gtk_widget_get_allocated_width(widget);
    int height = gtk_widget_get_allocated_height(widget);

    cairo_set_source_rgb(cr, 0.15, 0.15, 0.15);
    cairo_paint(cr);

    if (chart_count == 0) {
        cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
        cairo_select_font_face(cr, "Sans", CAIRO_FONT_SLANT_ITALIC, CAIRO_FONT_WEIGHT_NORMAL);
        cairo_set_font_size(cr, 13);
        cairo_move_to(cr, 20, height / 2.0);
        cairo_show_text(cr, "Zadajte hlasy a kliknite Spočítať");
        return FALSE;
    }

    int margin_left = 20, margin_right = 20, margin_top = 24, margin_bottom = 70;
    int max_votes = chart_students[0].votes;
    int n = chart_count > 20 ? 20 : chart_count;

    double bar_area_w = width - margin_left - margin_right;
    double bar_area_h = height - margin_top - margin_bottom;
    double slot = bar_area_w / n;
    double bar_w = slot - 6;

    for (int i = 0; i < n; i++) {
        double bar_h = (bar_area_h * chart_students[i].votes) / (double)max_votes;
        double x = margin_left + i * slot + 3;
        double y = margin_top + bar_area_h - bar_h;

        int ci = i < 3 ? i : (3 + (i % (NUM_COLORS - 3)));
        cairo_set_source_rgb(cr, bar_colors[ci][0], bar_colors[ci][1], bar_colors[ci][2]);
        cairo_rectangle(cr, x, y, bar_w, bar_h);
        cairo_fill(cr);

        // Vote count on top
        cairo_set_source_rgb(cr, 1, 1, 1);
        cairo_select_font_face(cr, "Sans", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_BOLD);
        cairo_set_font_size(cr, 11);
        char vs[16];
        snprintf(vs, sizeof(vs), "%d", chart_students[i].votes);
        cairo_text_extents_t ext;
        cairo_text_extents(cr, vs, &ext);
        cairo_move_to(cr, x + (bar_w - ext.width) / 2.0, y - 5);
        cairo_show_text(cr, vs);

        // Name rotated below bar
        cairo_save(cr);
        cairo_translate(cr, x + bar_w / 2.0, height - margin_bottom + 10);
        cairo_rotate(cr, -G_PI / 4.0);
        cairo_set_source_rgb(cr, 0.9, 0.9, 0.9);
        cairo_select_font_face(cr, "Sans", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
        cairo_set_font_size(cr, 10);
        char short_name[24];
        if (strlen(chart_students[i].name) > 20) {
            strncpy(short_name, chart_students[i].name, 19);
            short_name[19] = '\0';
            strcat(short_name, "~");
        } else {
            strncpy(short_name, chart_students[i].name, sizeof(short_name) - 1);
            short_name[sizeof(short_name)-1] = '\0';
        }
        cairo_move_to(cr, 0, 0);
        cairo_show_text(cr, short_name);
        cairo_restore(cr);
    }
    return FALSE;
}

static void calculate(GtkWidget *widget, gpointer data) {
    (void)widget; (void)data;

    GtkTextBuffer *buf = gtk_text_view_get_buffer(GTK_TEXT_VIEW(text_input));
    GtkTextIter start, end;
    gtk_text_buffer_get_start_iter(buf, &start);
    gtk_text_buffer_get_end_iter(buf, &end);
    char *text = gtk_text_buffer_get_text(buf, &start, &end, FALSE);

    Student students[MAX_STUDENTS];
    int count = 0, loaded = 0;

    char *line = strtok(text, "\n");
    while (line != NULL) {
        if (strlen(line) == 0 || line[0] == '\r') { line = strtok(NULL, "\n"); continue; }
        int votes; char name[MAX_NAME];
        if (sscanf(line, "%d %255[^\n\r]", &votes, name) != 2 || votes <= 0) break;
        loaded++;
        int idx = find_student(students, count, name);
        if (idx >= 0) { students[idx].votes += votes; }
        else if (count < MAX_STUDENTS) { strncpy(students[count].name, name, MAX_NAME-1); students[count].votes = votes; count++; }
        line = strtok(NULL, "\n");
    }
    g_free(text);

    if (loaded == 0) { set_output("Nepodarilo nacitat nic"); chart_count = 0; gtk_widget_queue_draw(drawing_area); return; }

    qsort(students, count, sizeof(Student), cmp);
    chart_count = count;
    memcpy(chart_students, students, count * sizeof(Student));
    gtk_widget_queue_draw(drawing_area);

    char output[MAX_STUDENTS * (MAX_NAME + 16)];
    int pos = 0;
    pos += snprintf(output + pos, sizeof(output) - pos, "Vysledky:\n");
    for (int i = 0; i < count; i++)
        pos += snprintf(output + pos, sizeof(output) - pos, "%d %s\n", students[i].votes, students[i].name);
    set_output(output);
}

static void clear_all(GtkWidget *widget, gpointer data) {
    (void)widget; (void)data;
    gtk_text_buffer_set_text(gtk_text_view_get_buffer(GTK_TEXT_VIEW(text_input)), "", -1);
    set_output("");
    chart_count = 0;
    gtk_widget_queue_draw(drawing_area);
}

static void activate(GtkApplication *app, gpointer user_data) {
    (void)user_data;
    GtkWidget *window = gtk_application_window_new(app);
    gtk_window_set_title(GTK_WINDOW(window), "Anketa Študent roka");
    gtk_window_set_default_size(GTK_WINDOW(window), 900, 650);
    gtk_container_set_border_width(GTK_CONTAINER(window), 12);

    GtkWidget *hbox = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 12);
    gtk_container_add(GTK_CONTAINER(window), hbox);

    // Left panel
    GtkWidget *left = gtk_box_new(GTK_ORIENTATION_VERTICAL, 8);
    gtk_box_pack_start(GTK_BOX(hbox), left, FALSE, FALSE, 0);
    gtk_widget_set_size_request(left, 280, -1);

    gtk_box_pack_start(GTK_BOX(left), gtk_label_new("Hlasy (počet meno):"), FALSE, FALSE, 0);
    GtkWidget *scroll_in = gtk_scrolled_window_new(NULL, NULL);
    gtk_scrolled_window_set_min_content_height(GTK_SCROLLED_WINDOW(scroll_in), 220);
    gtk_box_pack_start(GTK_BOX(left), scroll_in, TRUE, TRUE, 0);
    text_input = gtk_text_view_new();
    gtk_text_view_set_monospace(GTK_TEXT_VIEW(text_input), TRUE);
    gtk_container_add(GTK_CONTAINER(scroll_in), text_input);

    GtkWidget *btn_box = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 8);
    gtk_box_pack_start(GTK_BOX(left), btn_box, FALSE, FALSE, 0);
    GtkWidget *btn_calc = gtk_button_new_with_label("Spočítať hlasy");
    g_signal_connect(btn_calc, "clicked", G_CALLBACK(calculate), NULL);
    gtk_box_pack_start(GTK_BOX(btn_box), btn_calc, TRUE, TRUE, 0);
    GtkWidget *btn_clear = gtk_button_new_with_label("Vymazať");
    g_signal_connect(btn_clear, "clicked", G_CALLBACK(clear_all), NULL);
    gtk_box_pack_start(GTK_BOX(btn_box), btn_clear, FALSE, FALSE, 0);

    gtk_box_pack_start(GTK_BOX(left), gtk_label_new("Výsledky:"), FALSE, FALSE, 0);
    GtkWidget *scroll_out = gtk_scrolled_window_new(NULL, NULL);
    gtk_scrolled_window_set_min_content_height(GTK_SCROLLED_WINDOW(scroll_out), 180);
    gtk_box_pack_start(GTK_BOX(left), scroll_out, TRUE, TRUE, 0);
    text_output = gtk_text_view_new();
    gtk_text_view_set_monospace(GTK_TEXT_VIEW(text_output), TRUE);
    gtk_text_view_set_editable(GTK_TEXT_VIEW(text_output), FALSE);
    gtk_container_add(GTK_CONTAINER(scroll_out), text_output);

    // Right panel: chart
    GtkWidget *right = gtk_box_new(GTK_ORIENTATION_VERTICAL, 4);
    gtk_box_pack_start(GTK_BOX(hbox), right, TRUE, TRUE, 0);
    gtk_box_pack_start(GTK_BOX(right), gtk_label_new("Graf hlasov:"), FALSE, FALSE, 0);
    drawing_area = gtk_drawing_area_new();
    gtk_box_pack_start(GTK_BOX(right), drawing_area, TRUE, TRUE, 0);
    g_signal_connect(drawing_area, "draw", G_CALLBACK(on_draw), NULL);

    gtk_widget_show_all(window);
}

int main(int argc, char **argv) {
    GtkApplication *app = gtk_application_new("sk.tuke.pvjc.anketa", G_APPLICATION_DEFAULT_FLAGS);
    g_signal_connect(app, "activate", G_CALLBACK(activate), NULL);
    int status = g_application_run(G_APPLICATION(app), argc, argv);
    g_object_unref(app);
    return status;
}