/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "Screen.h"
#include "Compositor.h"
#include "Event.h"
#include "EventLoop.h"
#include "WindowManager.h"
#include <Kernel/FB.h>
#include <Kernel/MousePacket.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>

namespace WindowServer {

static Screen* s_the;

Screen& Screen::the()
{
    ASSERT(s_the);
    return *s_the;
}

Screen::Screen(unsigned desired_width, unsigned desired_height)
{
    ASSERT(!s_the);
    s_the = this;
    m_framebuffer_fd = open("/dev/fb0", O_RDWR | O_CLOEXEC);
    if (m_framebuffer_fd < 0) {
        perror("failed to open /dev/fb0");
        ASSERT_NOT_REACHED();
    }

    if (fb_set_buffer(m_framebuffer_fd, 0) == 0) {
        m_can_set_buffer = true;
    }

    set_resolution(desired_width, desired_height);
    m_cursor_location = rect().center();
}

Screen::~Screen()
{
}

bool Screen::set_resolution(int width, int height)
{
    FBResolution resolution { 0, (unsigned)width, (unsigned)height };
    int rc = fb_set_resolution(m_framebuffer_fd, &resolution);
#ifdef WSSCREEN_DEBUG
    dbg() << "fb_set_resolution() - return code " << rc;
#endif
    if (rc == 0) {
        on_change_resolution(resolution.pitch, resolution.width, resolution.height);
        return true;
    }
    if (rc == -1) {
        dbg() << "Invalid resolution " << width << "x" << height;
        on_change_resolution(resolution.pitch, resolution.width, resolution.height);
        return false;
    }
    ASSERT_NOT_REACHED();
}

void Screen::on_change_resolution(int pitch, int width, int height)
{
    if (m_framebuffer) {
        size_t previous_size_in_bytes = m_size_in_bytes;
        int rc = munmap(m_framebuffer, previous_size_in_bytes);
        ASSERT(rc == 0);
    }

    int rc = fb_get_size_in_bytes(m_framebuffer_fd, &m_size_in_bytes);
    ASSERT(rc == 0);

    m_framebuffer = (Gfx::RGBA32*)mmap(nullptr, m_size_in_bytes, PROT_READ | PROT_WRITE, MAP_SHARED, m_framebuffer_fd, 0);
    ASSERT(m_framebuffer && m_framebuffer != (void*)-1);

    m_pitch = pitch;
    m_width = width;
    m_height = height;

    m_cursor_location.constrain(rect());
}

void Screen::set_buffer(int index)
{
    ASSERT(m_can_set_buffer);
    int rc = fb_set_buffer(m_framebuffer_fd, index);
    ASSERT(rc == 0);
}

void Screen::on_receive_mouse_data(const MousePacket& packet)
{
    auto prev_location = m_cursor_location;
    if (packet.is_relative) {
        m_cursor_location.move_by(packet.x, packet.y);
#ifdef WSSCREEN_DEBUG
        dbgprintf("Screen: New Relative mouse point @ X %d, Y %d\n", m_cursor_location.x(), m_cursor_location.y());
#endif
    } else {
        m_cursor_location = { packet.x * m_width / 0xffff, packet.y * m_height / 0xffff };
#ifdef WSSCREEN_DEBUG
        dbgprintf("Screen: New Absolute mouse point @ X %d, Y %d\n", m_cursor_location.x(), m_cursor_location.y());
#endif
    }

    m_cursor_location.constrain(rect());

    unsigned buttons = packet.buttons;
    unsigned prev_buttons = m_mouse_button_state;
    m_mouse_button_state = buttons;
    unsigned changed_buttons = prev_buttons ^ buttons;
    auto post_mousedown_or_mouseup_if_needed = [&](MouseButton button) {
        if (!(changed_buttons & (unsigned)button))
            return;
        auto message = make<MouseEvent>(buttons & (unsigned)button ? Event::MouseDown : Event::MouseUp, m_cursor_location, buttons, button, m_modifiers);
        Core::EventLoop::current().post_event(WindowManager::the(), move(message));
    };
    post_mousedown_or_mouseup_if_needed(MouseButton::Left);
    post_mousedown_or_mouseup_if_needed(MouseButton::Right);
    post_mousedown_or_mouseup_if_needed(MouseButton::Middle);
    post_mousedown_or_mouseup_if_needed(MouseButton::Back);
    post_mousedown_or_mouseup_if_needed(MouseButton::Forward);
    if (m_cursor_location != prev_location) {
        auto message = make<MouseEvent>(Event::MouseMove, m_cursor_location, buttons, MouseButton::None, m_modifiers);
        Core::EventLoop::current().post_event(WindowManager::the(), move(message));
    }

    if (packet.z) {
        auto message = make<MouseEvent>(Event::MouseWheel, m_cursor_location, buttons, MouseButton::None, m_modifiers, packet.z);
        Core::EventLoop::current().post_event(WindowManager::the(), move(message));
    }

    if (m_cursor_location != prev_location)
        Compositor::the().invalidate_cursor();
}

void Screen::on_receive_keyboard_data(::KeyEvent kernel_event)
{
    m_modifiers = kernel_event.modifiers();
    auto message = make<KeyEvent>(kernel_event.is_press() ? Event::KeyDown : Event::KeyUp, kernel_event.key, kernel_event.character, kernel_event.modifiers(), kernel_event.scancode);
    Core::EventLoop::current().post_event(WindowManager::the(), move(message));
}

}