#include "TimerGraph.h"

#include <unistd.h>
#include <sys/wait.h>

struct _TimerGraph {
    GtkBin parent;

    GtkWidget *drawingArea;

    GdkPixbuf *originalData;
    cairo_surface_t *tex;
    double gx;
    double gy;
};

G_DEFINE_TYPE(TimerGraph, timer_graph, GTK_TYPE_BIN);

static char *get_graph_format() {
    GSList *list = gdk_pixbuf_get_formats();
    GSList *i;
    for (i = list; i != NULL; i = i->next) {
        GdkPixbufFormat *f = i->data;
        if (!gdk_pixbuf_format_is_disabled(f)) {
            gchar **exts = gdk_pixbuf_format_get_extensions(f);
            while (*exts != NULL) {
                if (strcmp(*exts, PLOTUTILS_PREFERRED_FORMAT) == 0){
                    g_slist_free(list);
                    return PLOTUTILS_PREFERRED_FORMAT;
                }
                ++exts;
            }
        }
    }
    g_warning("fallback image forat ('" PLOTUTILS_FALLBACK_FORMAT "') used");
    g_slist_free(list);
    return PLOTUTILS_FALLBACK_FORMAT;
}

static char *create_graph_bytes(const TimerGraphPoint *verts, gsize length, const char *format, const char *xLabel, const char *yLabel, const char *title, gsize *len) {
    GString *dataString = g_string_new(NULL);
    gsize i;
    for (i = 0; i < length; ++i) {
        g_string_append_printf(dataString, "%d.0 %d.0", verts[i].x, verts[i].y);
        if (i < length - 1) {
            g_string_append_c(dataString, '\n');
        }
    }
    char *pointsString = g_string_free(dataString, FALSE);
    int ptoc[2];
    if (pipe(ptoc) < 0) {
        g_free(pointsString);
        GtkWidget *diag = gtk_message_dialog_new(NULL, GTK_DIALOG_MODAL, GTK_MESSAGE_ERROR, GTK_BUTTONS_OK, "An internal error occured. Please try again.");
        gtk_window_set_position(GTK_WINDOW(diag), GTK_WIN_POS_MOUSE);
        gtk_dialog_run(GTK_DIALOG(diag));
        gtk_widget_destroy(diag);
        return NULL;
    }
    int ctop[2];
    if (pipe(ctop) < 0) {
        g_free(pointsString);
        close(ptoc[0]);
        close(ptoc[1]);
        GtkWidget *diag = gtk_message_dialog_new(NULL, GTK_DIALOG_MODAL, GTK_MESSAGE_ERROR, GTK_BUTTONS_OK, "An internal error occured. Please try again.");
        gtk_window_set_position(GTK_WINDOW(diag), GTK_WIN_POS_MOUSE);
        gtk_dialog_run(GTK_DIALOG(diag));
        gtk_widget_destroy(diag);
        return NULL;
    }
    pid_t p = fork();
    if (p == 0) {
        /* child */
        g_free(pointsString);
        dup2(ptoc[0], fileno(stdin));
        close(ptoc[1]);
        dup2(ctop[1], fileno(stdout));
        close(ctop[0]);
        freopen("/dev/null", "w", stderr);
        execlp(PLOTUTILS_GRAPH_PATH, PLOTUTILS_GRAPH_PATH, "-T", format, "-X", xLabel, "-Y", yLabel, "-L", title, NULL);
        /* If graph(1) could not be executed */
        exit(0);
    } else {
        /* parent */
        int out = ptoc[1];
        close(ptoc[0]);
        int in = ctop[0];
        close(ctop[1]);
        write(out, pointsString, strlen(pointsString));
        close(out);
        g_free(pointsString);
        int status;
        if (waitpid(p, &status, 0) < 0) {
            close(in);
            g_warning("graph(1) failed");
            return NULL;
        } else if (WIFEXITED(status) && WEXITSTATUS(status) != 0) {
            close(in);
            g_warning("graph(1) failed");
            return NULL;
        }
        GString *buff = g_string_new(NULL);
        char c;
        *len = 0;
        while (read(in, &c, 1) > 0) {
            g_string_append_c(buff, c);
            ++(*len);
        }
        close(in);
        char *resp = g_string_free(buff, FALSE);
        return resp;
    }
}

static GdkPixbuf *pixbuf_from_data(const char *data, gsize len) {
    GdkPixbufLoader *loader = gdk_pixbuf_loader_new();
    GError *err = NULL;
    gdk_pixbuf_loader_write(loader, (const guchar *) data, len, &err);
    gdk_pixbuf_loader_close(loader, NULL);
    if (err != NULL) {
        GtkWidget *diag = gtk_message_dialog_new(NULL, GTK_DIALOG_MODAL, GTK_MESSAGE_ERROR, GTK_BUTTONS_OK, "An internal error occured. Please try again.");
        gtk_window_set_position(GTK_WINDOW(diag), GTK_WIN_POS_MOUSE);
        gtk_dialog_run(GTK_DIALOG(diag));
        gtk_widget_destroy(diag);
        g_object_unref(loader);
        g_error_free(err);
        return NULL;
    }
    GdkPixbuf *pixbuf = gdk_pixbuf_loader_get_pixbuf(loader);
    g_object_ref(pixbuf);
    g_object_unref(loader);
    return pixbuf;
}

static void da_size_callback(GtkDrawingArea *self, GtkAllocation *allocation, TimerGraph *graph) {
    if (graph->originalData) {
        int size = MIN(allocation->width, allocation->height);
        if (graph->tex) {
            cairo_surface_destroy(graph->tex);
        }
        graph->gx = ((double) allocation->width / 2) - ((double) size / 2);
        graph->gy = ((double) allocation->height / 2) - ((double) size / 2);
        GdkPixbuf *scaled = gdk_pixbuf_scale_simple(graph->originalData, size, size, GDK_INTERP_BILINEAR);
        graph->tex = gdk_cairo_surface_create_from_pixbuf(scaled, 1, gtk_widget_get_window(GTK_WIDGET(self)));
        g_object_unref(scaled);
    }
}

static gboolean da_draw_callback(GtkDrawingArea *self, cairo_t *cr, TimerGraph *graph) {
    GtkStyleContext *cxt = gtk_widget_get_style_context(GTK_WIDGET(self));
    guint width = gtk_widget_get_allocated_width(GTK_WIDGET(self));
    guint height = gtk_widget_get_allocated_height(GTK_WIDGET(self));
    gtk_render_background(cxt, cr, 0, 0, width, height);
    if (graph->tex) {
        cairo_set_source_surface(cr, graph->tex, graph->gx, graph->gy);
    }
    cairo_paint(cr);
    return TRUE;
}

GtkWidget *timer_graph_new(const TimerGraphPoint *verts, gsize length, const char *xLabel, const char *yLabel, const char *title) {
    TimerGraph *g = g_object_new(TIMER_TYPE_GRAPH, NULL);
    gsize len = 0;
    char *data = create_graph_bytes(verts, length, get_graph_format(), xLabel, yLabel, title, &len);
    g->originalData = pixbuf_from_data(data, len);
    g_free(data);
    return GTK_WIDGET(g);
}

static void timer_graph_finalize(GObject *obj) {
    TimerGraph *self = TIMER_GRAPH(obj);
    if (self->originalData) {
        g_object_unref(self->originalData);
    }
    if (self->tex) {
        cairo_surface_destroy(self->tex);
    }
    G_OBJECT_CLASS(timer_graph_parent_class)->finalize(obj);
}

static void timer_graph_class_init(TimerGraphClass *class) {
    G_OBJECT_CLASS(class)->finalize = timer_graph_finalize;
}

static void timer_graph_init(TimerGraph* self) {
    self->drawingArea = gtk_drawing_area_new();
    gtk_container_add(GTK_CONTAINER(self), self->drawingArea);
    gtk_widget_set_size_request(GTK_WIDGET(self), 100, 100);
    g_signal_connect(self->drawingArea, "size-allocate", G_CALLBACK(da_size_callback), self);
    g_signal_connect(self->drawingArea, "draw", G_CALLBACK(da_draw_callback), self);
}