/*
winnie - an experimental window system

Copyright (C) 2013 Eleni Maria Stea

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

Author: Eleni Maria Stea <elene.mst@gmail.com>
*/

#include <algorithm>
#include <limits.h>
#include <stdexcept>
#include <stdint.h>
#include <stdio.h>

#include "gfx.h"
#include "mouse_cursor.h"
#include "sdl/gfx.h"
#include "sdl/mouse.h"
#include "text.h"
#include "window.h"
#include "winnie.h"
#include "wm.h"

#define DCLICK_INTERVAL 400

WindowManager *wm;

static void display(Window *win);
static void mouse(Window *win, int bn, bool pressed, int x, int y);
static void motion(Window *win, int x, int y);

bool
init_window_manager()
{
  void *wm_mem;
  if (!(wm_mem = malloc(sizeof *wm))) {
    return false;
  }

  wm = new (wm_mem) WindowManager;

  return true;
}

void
destroy_window_manager()
{
  wm->~WindowManager();
  free(wm);
}

void
WindowManager::create_frame(Window *win)
{
  Window *frame = new Window;
  Window *parent = win->get_parent();

  frame->set_display_callback(display);
  frame->set_mouse_button_callback(mouse);
  frame->set_mouse_motion_callback(motion);
  frame->set_focusable(false);
  frame->add_child(win);

  windows.push_back(frame);

  Rect win_rect = win->get_rect();
  frame->move(win_rect.x - frame_thickness,
              win_rect.y - frame_thickness - titlebar_thickness);
  frame->resize(win_rect.width + frame_thickness * 2,
                win_rect.height + frame_thickness * 2 + titlebar_thickness);

  win->move(frame_thickness, frame_thickness + titlebar_thickness);
  parent->add_child(frame);
}

void
WindowManager::destroy_frame(Window *win)
{
  Window *frame = win->parent;
  if (!frame) {
    return;
  }

  if (grab_win == win) {
    release_mouse();
  }

  std::list<Window *>::iterator it;
  it = std::find(windows.begin(), windows.end(), frame);
  if (it != windows.end()) {
    root_win->add_child(win);
    windows.erase(it);
    delete frame;
  }
}

WindowManager::WindowManager()
{
  if (!wm) {
    wm = this;
  } else {
    /* Trying to create a second instance of WindowManager */
  }

  root_win = new Window;
  root_win->resize(get_screen_size().width, get_screen_size().height);
  root_win->move(0, 0);
  root_win->set_managed(false);

  grab_win = 0;
  focused_win = 0;
  background = 0;

  bg_color[0] = 210;
  bg_color[1] = 106;
  bg_color[2] = 106;

  frame_thickness = 6;
  titlebar_thickness = 18;

  set_focused_frame_color(64, 64, 64);
  set_unfocused_frame_color(160, 160, 160);
  set_bevel_size(2);

  mouse_cursor.set_image(mouse_cursor_width, mouse_cursor_height);
  unsigned char *pixels = mouse_cursor.get_image();

  for (int i = 0; i < mouse_cursor_height; i++) {
    for (int j = 0; j < mouse_cursor_width; j++) {
      int val = mouse_cursor_bw[i * mouse_cursor_width + j];
      *pixels++ = val;
      *pixels++ = val;
      *pixels++ = val;
      *pixels++ = 255;
    }
  }
}

WindowManager::~WindowManager() { delete root_win; }

void
WindowManager::invalidate_region(const Rect &rect)
{
  dirty_rects.push_back(rect);
}

void
WindowManager::process_windows()
{
  if (dirty_rects.empty()) {
    return;
  }

  std::list<Rect>::iterator drit = dirty_rects.begin();
  Rect uni = *drit++;
  while (drit != dirty_rects.end()) {
    uni = rect_union(uni, *drit++);
  }
  dirty_rects.clear();

  if (!background) {
    fill_rect(uni, bg_color[0], bg_color[1], bg_color[2]);
  } else {
    blit(background->pixels,
         Rect(0, 0, background->width, background->height),
         get_framebuffer(),
         get_screen_size(),
         0,
         0);
  }

  root_win->draw_children(uni);

  // draw mouse cursor
  int mouse_x, mouse_y;
  get_pointer_pos(&mouse_x, &mouse_y);

  blit_key(mouse_cursor.get_image(),
           mouse_cursor.get_rect(),
           get_framebuffer(),
           get_screen_size(),
           mouse_x,
           mouse_y,
           0,
           0,
           0);

  Rect mouse_rect(
      mouse_x, mouse_y, mouse_cursor.get_width(), mouse_cursor.get_height());
  invalidate_region(mouse_rect);

  gfx_update(uni);
}

void
WindowManager::add_window(Window *win)
{
  if (!win || win == root_win) {
    return;
  }

  root_win->add_child(win);

  if (windows.empty()) {
    focused_win = win;
  }

  if (win->get_managed()) {
    create_frame(win);
  }

  windows.push_back(win);
}

void
WindowManager::remove_window(Window *win)
{
  std::list<Window *>::iterator it;
  it = std::find(windows.begin(), windows.end(), win);

  if (it != windows.end()) {
    windows.erase(it);
  }
}

void
WindowManager::set_focused_window(Window *win)
{
  if (win && win == focused_win) {
    return;
  }

  if (focused_win) {
    // invalidate the frame (if any)
    Window *parent = focused_win->get_parent();
    if (parent && parent != root_win) {
      parent->invalidate();
    }
  }

  if (!win) {
    focused_win = 0;
    return;
  }

  if (win->get_focusable()) {
    focused_win = win;
    return;
  }

  Window **children = win->get_children();
  for (int i = 0; i < win->get_children_count(); i++) {
    if (children[0]->get_focusable()) {
      set_focused_window(children[0]);
      return;
    }
  }

  focused_win = 0;
}

const Window *
WindowManager::get_focused_window() const
{
  return focused_win;
}

Window *
WindowManager::get_focused_window()
{
  return focused_win;
}

Window *
WindowManager::get_window_at_pos(int pointer_x, int pointer_y)
{
  Window *root_win = wm->get_root_window();
  Window **children = root_win->get_children();
  for (int i = root_win->get_children_count() - 1; i >= 0; i--) {
    if (children[i]->contains_point(pointer_x, pointer_y)) {
      return children[i];
    }
  }

  return 0;
}

Window *
WindowManager::get_root_window() const
{
  return root_win;
}

void
WindowManager::set_focused_frame_color(int r, int g, int b)
{
  frame_fcolor[0] = r;
  frame_fcolor[1] = g;
  frame_fcolor[2] = b;
}

void
WindowManager::get_focused_frame_color(int *r, int *g, int *b) const
{
  *r = frame_fcolor[0];
  *g = frame_fcolor[1];
  *b = frame_fcolor[2];
}

void
WindowManager::set_unfocused_frame_color(int r, int g, int b)
{
  frame_ucolor[0] = r;
  frame_ucolor[1] = g;
  frame_ucolor[2] = b;
}

void
WindowManager::get_unfocused_frame_color(int *r, int *g, int *b) const
{
  *r = frame_ucolor[0];
  *g = frame_ucolor[1];
  *b = frame_ucolor[2];
}

void
WindowManager::set_frame_size(int sz)
{
  frame_thickness = sz;
}

int
WindowManager::get_frame_size() const
{
  return frame_thickness;
}

void
WindowManager::set_titlebar_size(int sz)
{
  titlebar_thickness = sz;
}

int
WindowManager::get_titlebar_size() const
{
  return titlebar_thickness;
}

void
WindowManager::set_bevel_size(int sz)
{
  bevel_sz = sz;
}

int
WindowManager::get_bevel_size() const
{
  return bevel_sz;
}

void
WindowManager::set_background_color(int r, int g, int b)
{
  bg_color[0] = r;
  bg_color[1] = g;
  bg_color[2] = b;
}

void
WindowManager::get_background_color(int *r, int *g, int *b) const
{
  *r = bg_color[0];
  *g = bg_color[1];
  *b = bg_color[2];
}

void
WindowManager::set_background(const Pixmap *pixmap)
{
  if (background) {
    delete background;
  }

  if (pixmap) {
    background = new Pixmap(*pixmap);
  } else {
    background = 0;
  }
}

const Pixmap *
WindowManager::get_background() const
{
  return background;
}

Window *
WindowManager::get_grab_window() const
{
  return grab_win;
}

void
WindowManager::grab_mouse(Window *win)
{
  grab_win = win;
}

void
WindowManager::release_mouse()
{
  grab_win = 0;
}

void
WindowManager::raise_window(Window *win)
{
  if (!win) {
    return;
  }

  Window *parent = win->get_parent();
  if (parent != root_win) {
    if (parent->get_parent() == root_win) {
      win = parent;
    } else {
      return;
    }
  }

  root_win->remove_child(win);
  root_win->add_child(win);
}

void
WindowManager::sink_window(Window *win)
{
  if (!win) {
    return;
  }

  std::list<Window *>::iterator it;
  it = std::find(windows.begin(), windows.end(), win);
  if (it != windows.end()) {
    windows.erase(it);
    windows.push_front(win);
  }
}

void
WindowManager::maximize_window(Window *win)
{
  win->normal_rect = win->rect;

  Rect rect = get_screen_size();

  Window *frame;
  if ((frame = win->get_parent())) {
    frame->normal_rect = frame->rect;
    frame->resize(rect.width, rect.height);
    frame->move(rect.x, rect.y);

    rect.width -= frame_thickness * 2;
    rect.height -= frame_thickness * 2 + titlebar_thickness;
  } else {
    win->move(0, 0);
  }

  win->resize(rect.width, rect.height);
  win->set_state(Window::STATE_MAXIMIZED);

  invalidate_region(rect);
}

void
WindowManager::unmaximize_window(Window *win)
{
  win->resize(win->normal_rect.width, win->normal_rect.height);
  win->move(win->normal_rect.x, win->normal_rect.y);

  Window *frame;
  if ((frame = win->get_parent())) {
    frame->resize(frame->normal_rect.width, frame->normal_rect.height);
    frame->move(frame->normal_rect.x, frame->normal_rect.y);
  }

  win->set_state(Window::STATE_NORMAL);
}

static void
display(Window *win)
{
  // frame display:
  Window *child = win->get_children()[0];
  int r, g, b;
  Rect rect = win->get_absolute_rect();

  int tbar = wm->get_titlebar_size();
  int frm = wm->get_frame_size();

  if (child == wm->get_focused_window()) {
    wm->get_focused_frame_color(&r, &g, &b);
  } else {
    wm->get_unfocused_frame_color(&r, &g, &b);
  }

  // draw the four frame sides (top, bottom, left, right)
  fill_rect(Rect(rect.x, rect.y, rect.width, frm), r, g, b);
  fill_rect(
      Rect(rect.x, rect.y + rect.height - frm, rect.width, frm), r, g, b);
  fill_rect(Rect(rect.x, rect.y + frm, frm, rect.height - 2 * frm), r, g, b);
  fill_rect(
      Rect(
          rect.x + rect.width - frm, rect.y + frm, frm, rect.height - 2 * frm),
      r,
      g,
      b);
  // draw the titlebar
  fill_rect(
      Rect(rect.x + frm, rect.y + frm, rect.width - 2 * frm, tbar), r, g, b);

  int val = (r + g + b) / 3;
  int roffs = val < 128 ? r / 2 : (255 - r) / 2;
  int goffs = val < 128 ? g / 2 : (255 - g) / 2;
  int boffs = val < 128 ? b / 2 : (255 - b) / 2;

  // draw bevels
  int dark_r = r - roffs;
  int dark_g = g - goffs;
  int dark_b = b - boffs;

  int lt_r = r + roffs;
  int lt_g = g + goffs;
  int lt_b = b + boffs;

  set_text_position(rect.x + frm + 2, rect.y + frm + tbar - 5);
  set_text_color(80, 80, 80);
  draw_text(child->get_title());
  set_text_position(rect.x + frm + 1, rect.y + frm + tbar - 6);
  set_text_color(255, 255, 255);
  draw_text(child->get_title());

  int bevel = wm->get_bevel_size();
  fill_rect(Rect(rect.x, rect.y, bevel, rect.height), lt_r, lt_g, lt_b);
  fill_rect(Rect(rect.x, rect.y + rect.height - bevel, rect.width, bevel),
            dark_r,
            dark_g,
            dark_b);
  fill_rect(Rect(rect.x + rect.width - bevel, rect.y, bevel, rect.height),
            dark_r,
            dark_g,
            dark_b);
  fill_rect(Rect(rect.x, rect.y, rect.width, bevel), lt_r, lt_g, lt_b);

  Rect inner = Rect(rect.x + frm,
                    rect.y + frm + tbar,
                    rect.width - frm * 2,
                    rect.height - frm * 2 - tbar);
  fill_rect(Rect(inner.x - bevel,
                 inner.y + inner.height,
                 inner.width + 2 * bevel,
                 bevel),
            lt_r,
            lt_g,
            lt_b);
  fill_rect(
      Rect(inner.x - bevel, inner.y - bevel, bevel, inner.height + 2 * bevel),
      dark_r,
      dark_g,
      dark_b);
  fill_rect(Rect(inner.x + inner.width,
                 inner.y - bevel,
                 bevel,
                 inner.height + 2 * bevel),
            lt_r,
            lt_g,
            lt_b);
  fill_rect(
      Rect(inner.x - bevel, inner.y - bevel, inner.width + 2 * bevel, bevel),
      dark_r,
      dark_g,
      dark_b);
}

static int prev_x, prev_y;

static void
mouse(Window *win, int bn, bool pressed, int x, int y)
{
  static long last_click = 0;

  if (bn == 0) {
    if (pressed) {
      wm->grab_mouse(win);
      wm->raise_window(win);
      prev_x = x;
      prev_y = y;
    } else {
      long time = winnie_get_time();
      if ((time - last_click) < DCLICK_INTERVAL) {
        Window *child = win->get_children()[0];
        Window::State state = child->get_state();
        if (state == Window::STATE_MAXIMIZED) {
          wm->unmaximize_window(child);
        } else if (state == Window::STATE_NORMAL) {
          wm->maximize_window(child);
        }
      }
      last_click = time;

      wm->release_mouse();
    }
  }
}

static void
motion(Window *win, int x, int y)
{
  int left_bn = get_button(0);

  if (left_bn) {
    int dx = x - prev_x;
    int dy = y - prev_y;
    prev_x = x - dx;
    prev_y = y - dy;

    if (win->get_children()[0]->get_state() != Window::STATE_MAXIMIZED) {
      Rect rect = win->get_rect();
      win->move(rect.x + dx, rect.y + dy);
    }
  }
}