#include <math.h>
#include <iostream>
#include <clocale>
using namespace std;

#include <gtk/gtk.h>
#include <glib.h>

#include "haader.h"
#include "image.h"

struct Gui {
    GtkWidget *window;
    GtkWidget *canvas;
    GtkWidget *log_checkbox;
    GtkWidget *scale_exposure;
    GtkWidget *scale_compression;
    haader::HdrImageStack stack;
    haader::HdrImage hdr_image;
    haader::ResponseFunction response_function;
    haader::Image ldr_image;
    haader::Histogram hdr_histogram;
    haader::LdrHistogram ldr_histogram;
    cairo_surface_t *surface;
    double exposure_time;
    double compression;
};

static cairo_surface_t* image_to_cairo_surface(const haader::Image &image) {
    unsigned int width = image.get_width();
    unsigned int height = image.get_height();
    const unsigned char *image_data = image.get_const_image_data();

    cairo_surface_t *surf = cairo_image_surface_create(CAIRO_FORMAT_RGB24, width, height);
    int stride = cairo_image_surface_get_stride(surf);
    unsigned char *surf_data = cairo_image_surface_get_data(surf);

    unsigned int i = 0;
    unsigned int k = 0;
    for (unsigned int y = 0; y < height; y++) {
        for (unsigned int x = 0; x < width; x++) {
            surf_data[i + x * 4] = image_data[k + x * 3 + 2];
            surf_data[i + x * 4 + 1] = image_data[k + x * 3 + 1];
            surf_data[i + x * 4 + 2] = image_data[k + x * 3];
        }
        i += stride;
        k += width * 3;
    }

    return surf;
}

static void expose(Gui &gui) {
    gui.ldr_image = gui.hdr_image.expose(gui.exposure_time, gui.response_function, gui.compression);
    gui.ldr_histogram = gui.ldr_image.histogram();
    if (gui.surface) {
        cairo_surface_destroy(gui.surface);
        gui.surface = NULL;
    }
    gui.surface = image_to_cairo_surface(gui.ldr_image);
}

static void create_log_image(Gui &gui) {
    gui.ldr_image = gui.hdr_image.get_log_image();
    gui.ldr_histogram = gui.ldr_image.histogram();
    if (gui.surface) {
        cairo_surface_destroy(gui.surface);
        gui.surface = NULL;
    }
    gui.surface = image_to_cairo_surface(gui.ldr_image);
}

static gboolean canvas_draw(GtkWidget *widget, cairo_t *cr, gpointer user_data)
{
    cairo_set_source_rgb(cr, 0.2, 0.2, 0.2);
    cairo_paint(cr);

    Gui *gui = (Gui*) user_data;
    if (!gui->surface) {
        return false;
    }

    if (gui->hdr_histogram.m_bins.size() != 256) {
        return false;
    }

    if (gui->ldr_histogram.m_bins.size() != 256) {
        return false;
    }

    cairo_set_source_surface(cr, gui->surface, 5, 5);
    cairo_paint(cr);

    // canvas rect
    double cx = gui->ldr_image.get_width() + 10.0;
    double cy = 5.0;
    double cw = 256;
    double ch = 256;

    cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
    cairo_rectangle(cr, cx, cy, cw, ch);
    cairo_fill(cr);

    {
        double hist_scale = (256.0 / (double)(gui->hdr_histogram.m_max_freq));
        for (unsigned int i = 0; i < 256; i++) {
            double y = gui->hdr_histogram.m_bins[i] * hist_scale;
            cairo_rectangle(cr, cx + i, cy + ch - y, 1, y);
        }
        cairo_set_source_rgba(cr, 1.0, 0.0, 0.2, 0.4);
        cairo_fill(cr);
    }

    {
        double hist_scale = (256.0 / (double)(gui->ldr_histogram.m_max_freq));
        for (unsigned int i = 0; i < 256; i++) {
            double y = gui->ldr_histogram.m_bins[i] * hist_scale;
            cairo_rectangle(cr, cx + i, cy + ch - y, 1, y);
        }
        cairo_set_source_rgba(cr, 1.0, 0.0, 0.2, 0.9);
        cairo_fill(cr);
    }

    if (!gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(gui->log_checkbox))) {
        // Draw response function

        double minl = gui->hdr_histogram.m_min_value;
        double maxl = gui->hdr_histogram.m_max_value;
        double log_exp = log(gui->exposure_time);
        double scale = (maxl - minl) / 256.0;

        for (int i = 0; i < 256; i++) {
            double lum = minl + i * scale;
            int ly = gui->response_function.lookup((lum + log_exp) * gui->compression);
            cairo_line_to(cr, cx + i, cy + ch - ly);
        }
        cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, 0.8);
        cairo_set_line_width(cr, 1.0);
        cairo_stroke_preserve(cr);

        cairo_line_to(cr, cx + cw, cy + ch);
        cairo_line_to(cr, cx, cy + ch);
        cairo_close_path(cr);
        cairo_set_source_rgba(cr, 0.0, 0.5, 1.0, 0.2);
        cairo_fill(cr);
    }

    return FALSE;
}

void log_toggled(GtkToggleButton *button, gpointer user_data) {
    Gui *gui = (Gui*) user_data;

    if (gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(button))) {
        gtk_widget_set_sensitive(gui->scale_exposure, false);
        gtk_widget_set_sensitive(gui->scale_compression, false);
        create_log_image(*gui);
    } else {
        gtk_widget_set_sensitive(gui->scale_exposure, true);
        gtk_widget_set_sensitive(gui->scale_compression, true);
        expose(*gui);
    }

    gtk_widget_queue_draw(gui->canvas);
}

void scale_exposure_changed(GtkRange *range, gpointer user_data) {
    Gui *gui = (Gui*) user_data;

    gui->exposure_time = pow(2.0, gtk_range_get_value(range));

    expose(*gui);

    gtk_widget_queue_draw(gui->canvas);
}

void scale_compression_changed(GtkRange *range, gpointer user_data) {
    Gui *gui = (Gui*) user_data;

    gui->compression = pow(2.0, gtk_range_get_value(range));

    expose(*gui);

    gtk_widget_queue_draw(gui->canvas);
}

void file_select_clicked(GtkButton *button, gpointer user_data) {
    Gui *gui = (Gui*) user_data;

    GtkWidget *dialog = gtk_file_chooser_dialog_new(
            "Open File",
            GTK_WINDOW(gui->window),
            GTK_FILE_CHOOSER_ACTION_OPEN,
            "Cancel",
            GTK_RESPONSE_CANCEL,
            "Open",
            GTK_RESPONSE_ACCEPT,
            NULL);

    gtk_file_chooser_set_select_multiple (GTK_FILE_CHOOSER(dialog), true);

    bool ok = true;
    if (gtk_dialog_run(GTK_DIALOG(dialog)) == GTK_RESPONSE_ACCEPT) {
        gui->stack = haader::HdrImageStack();

        vector<string> path_list;
        {
            GSList *list = gtk_file_chooser_get_filenames(GTK_FILE_CHOOSER(dialog));

            GSList *element = list;
            while (element != NULL) {
                path_list.push_back(string((const char*)(element->data)));
                g_free(element->data);
                element = g_slist_next(element);
                if (!ok) {
                    break;
                }
            }

            g_slist_free(list);
        }

        if (path_list.size() == 1) {
            ok = gui->stack.read_from_csv_file(path_list[0].c_str());
        } else {
            for (unsigned int i = 0; i < path_list.size(); i++) {
                ok = ok && gui->stack.add_from_file_path(path_list[i].c_str());
            }
        }
    }

    if (ok) {
        // create HDR-image
        haader::InverseResponseFunction irf;
        if (gui->stack.get_inverse_response_function(irf, 4096)) {
            gui->hdr_image = gui->stack.get_hdr_image(irf);
            gui->ldr_image = gui->hdr_image.get_log_image();
            gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(gui->log_checkbox), true);
            gui->hdr_histogram = gui->hdr_image.histogram(256);
            gui->ldr_histogram = gui->ldr_image.histogram();
            if (gui->surface) {
                cairo_surface_destroy(gui->surface);
                gui->surface = NULL;
            }
            gui->surface = image_to_cairo_surface(gui->ldr_image);
            gui->response_function = irf.to_response_function(1024);
        }

        gtk_widget_queue_draw(gui->canvas);
    }

    gtk_widget_destroy (dialog);
}

int main(int argc, char *argv[])
{
    gtk_init(&argc, &argv);

    Gui gui;
    gui.surface = NULL;
    gui.exposure_time = 0.125;
    gui.compression = 1.0;

    gui.window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title(GTK_WINDOW(gui.window), "haader");
    gtk_window_set_default_size(GTK_WINDOW(gui.window), 800, 600);

    GtkWidget *file_button = gtk_button_new_with_label("Select files");
    gui.canvas = gtk_drawing_area_new();

    gui.log_checkbox = gtk_check_button_new_with_label("Logarithmic");
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(gui.log_checkbox), true);

    gui.scale_exposure = gtk_scale_new_with_range(GTK_ORIENTATION_HORIZONTAL, -20.0, 4.0, 0.001);
    gtk_range_set_value(GTK_RANGE(gui.scale_exposure), log(gui.exposure_time) / log(2));

    gui.scale_compression = gtk_scale_new_with_range(GTK_ORIENTATION_HORIZONTAL, -4, 4.0, 0.001);
    gtk_scale_add_mark(GTK_SCALE(gui.scale_compression), 0.0, GTK_POS_BOTTOM, "0");
    gtk_range_set_value(GTK_RANGE(gui.scale_compression), log(gui.compression) / log(2));

    gtk_widget_set_sensitive(gui.scale_exposure, false);
    gtk_widget_set_sensitive(gui.scale_compression, false);

    GtkWidget *vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 5);

    gtk_container_add(GTK_CONTAINER(gui.window), vbox);
    gtk_box_pack_start(GTK_BOX(vbox), file_button, false, false, 0);
    gtk_box_pack_start(GTK_BOX(vbox), gui.canvas, true, true, 0);

    GtkWidget *grid = gtk_grid_new();
    gtk_box_pack_start(GTK_BOX(vbox), grid, false, false, 0);

    gtk_grid_attach(GTK_GRID(grid), gui.log_checkbox, 1, 0, 1, 1);

    {
        GtkWidget *label = gtk_label_new("Exposure");
        gtk_grid_attach(GTK_GRID(grid), label, 0, 1, 1, 1);
        gtk_widget_set_size_request(gui.scale_exposure, 600, -1);
        gtk_grid_attach(GTK_GRID(grid), gui.scale_exposure, 1, 1, 1, 1);
    }

    {
        GtkWidget *label = gtk_label_new("Compression");
        gtk_grid_attach(GTK_GRID(grid), label, 0, 2, 1, 1);
        gtk_widget_set_size_request(gui.scale_compression, 600, -1);
        gtk_grid_attach(GTK_GRID(grid), gui.scale_compression, 1, 2, 1, 1);
    }

    g_signal_connect(gui.window, "destroy", G_CALLBACK(gtk_main_quit), NULL);
    g_signal_connect(gui.canvas, "draw", G_CALLBACK(canvas_draw), &gui);
    g_signal_connect(file_button, "clicked", G_CALLBACK(file_select_clicked), &gui);
    g_signal_connect(gui.log_checkbox, "toggled", G_CALLBACK(log_toggled), &gui);
    g_signal_connect(gui.scale_exposure, "value-changed", G_CALLBACK(scale_exposure_changed), &gui);
    g_signal_connect(gui.scale_compression, "value-changed", G_CALLBACK(scale_compression_changed), &gui);

    gtk_widget_show_all(gui.window);

    // Set C-locale number format.
    // Make strtod work with strings like "0.1" (instead of "0,1")
    std::setlocale(LC_NUMERIC, "C");

    gtk_main ();

    return 0;
}