/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
#include "SkOSWindow_SDL.h"
#include "SkCanvas.h"

#if defined(SK_BUILD_FOR_ANDROID)
#include <GLES/gl.h>
#elif defined(SK_BUILD_FOR_UNIX)
#include <GL/gl.h>
#elif defined(SK_BUILD_FOR_MAC)
#include <gl.h>
#endif

const int kInitialWindowWidth = 640;
const int kInitialWindowHeight = 480;
static SkOSWindow* gCurrentWindow;

static void report_sdl_error(const char* failure) {
    const char* error = SDL_GetError();
    SkASSERT(error); // Called only to check SDL error.
    SkDebugf("%s SDL Error: %s.\n", failure, error);
    SDL_ClearError();
}
SkOSWindow::SkOSWindow(void*)
    : fWindow(nullptr)
    , fGLContext(nullptr)
    , fWindowMSAASampleCount(0) {

    SkASSERT(!gCurrentWindow);
    gCurrentWindow = this;

    this->createWindow(0);
}

SkOSWindow::~SkOSWindow() {
    this->destroyWindow();
    gCurrentWindow = nullptr;
}

SkOSWindow* SkOSWindow::GetInstanceForWindowID(Uint32 windowID) {
    if (gCurrentWindow &&
        gCurrentWindow->fWindow &&
        SDL_GetWindowID(gCurrentWindow->fWindow) == windowID) {
        return gCurrentWindow;
    }
    return nullptr;
}

void SkOSWindow::detach() {
    if (fGLContext) {
        SDL_GL_DeleteContext(fGLContext);
        fGLContext = nullptr;
    }
}

bool SkOSWindow::attach(SkBackEndTypes attachType, int msaaSampleCount, AttachmentInfo* info) {
    this->createWindow(msaaSampleCount);
    if (!fWindow) {
        return false;
    }
    if (!fGLContext) {
        fGLContext = SDL_GL_CreateContext(fWindow);
        if (!fGLContext) {
            report_sdl_error("Failed to create SDL GL context.");
            return false;
        }
        glClearColor(0, 0, 0, 0);
        glClearStencil(0);
        glStencilMask(0xffffffff);
        glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
    }

    if (SDL_GL_MakeCurrent(fWindow, fGLContext) != 0) {
        report_sdl_error("Failed to make SDL GL context current.");
        this->detach();
        return false;
    }

    info->fSampleCount = msaaSampleCount;
    info->fStencilBits = 8;

    glViewport(0, 0, SkScalarRoundToInt(this->width()), SkScalarRoundToInt(this->height()));
    return true;
}

void SkOSWindow::present() {
    if (!fWindow) {
        return;
    }
    SDL_GL_SwapWindow(fWindow);
}

bool SkOSWindow::makeFullscreen() {
    if (!fWindow) {
        return false;
    }
    SDL_SetWindowFullscreen(fWindow, SDL_WINDOW_FULLSCREEN_DESKTOP);
    return true;
}

void SkOSWindow::setVsync(bool vsync) {
    if (!fWindow) {
        return;
    }
    SDL_GL_SetSwapInterval(vsync ? 1 : 0);
}

void SkOSWindow::closeWindow() {
    this->destroyWindow();

    // Currently closing the window causes the app to quit.
    SDL_Event event;
    event.type = SDL_QUIT;
    SDL_PushEvent(&event);
}

static SkKey convert_sdlkey_to_skkey(SDL_Keycode src) {
    switch (src) {
        case SDLK_UP:
            return kUp_SkKey;
        case SDLK_DOWN:
            return kDown_SkKey;
        case SDLK_LEFT:
            return kLeft_SkKey;
        case SDLK_RIGHT:
            return kRight_SkKey;
        case SDLK_HOME:
            return kHome_SkKey;
        case SDLK_END:
            return kEnd_SkKey;
        case SDLK_ASTERISK:
            return kStar_SkKey;
        case SDLK_HASH:
            return kHash_SkKey;
        case SDLK_0:
            return k0_SkKey;
        case SDLK_1:
            return k1_SkKey;
        case SDLK_2:
            return k2_SkKey;
        case SDLK_3:
            return k3_SkKey;
        case SDLK_4:
            return k4_SkKey;
        case SDLK_5:
            return k5_SkKey;
        case SDLK_6:
            return k6_SkKey;
        case SDLK_7:
            return k7_SkKey;
        case SDLK_8:
            return k8_SkKey;
        case SDLK_9:
            return k9_SkKey;
        default:
            return kNONE_SkKey;
    }
}

void SkOSWindow::createWindow(int msaaSampleCount) {
    if (fWindowMSAASampleCount != msaaSampleCount) {
        this->destroyWindow();
    }
    if (fWindow) {
        return;
    }
    uint32_t windowFlags =
#if defined(SK_BUILD_FOR_ANDROID)
            SDL_WINDOW_BORDERLESS | SDL_WINDOW_FULLSCREEN_DESKTOP |
            SDL_WINDOW_ALLOW_HIGHDPI |
#endif
            SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE;

    // GL settings are part of SDL_WINDOW_OPENGL window creation arguments.
#if defined(SK_BUILD_FOR_ANDROID)
    // TODO we should try and get a 3.0 context first
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
#else
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
#endif
    SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
    SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
    SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
    SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
    SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
#if defined(SK_BUILD_FOR_UNIX)
    // Apparently MSAA request matches "slow caveat". Make SDL not set anything for caveat for MSAA
    // by setting -1 for ACCELERATED_VISUAL. For non-MSAA, set ACCELERATED_VISUAL to 1 just for
    // compatiblity with other platforms.
    SDL_GL_SetAttribute(SDL_GL_ACCELERATED_VISUAL, msaaSampleCount > 0 ? -1 : 1);
#else
    SDL_GL_SetAttribute(SDL_GL_ACCELERATED_VISUAL, 1);
#endif
    SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, msaaSampleCount > 0 ? 1 : 0);
    SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, msaaSampleCount);

    // This is an approximation for sizing purposes.
    bool isInitialWindow = this->width() == 0 && this->height() == 0;
    SkScalar windowWidth = isInitialWindow ? kInitialWindowWidth : this->width();
    SkScalar windowHeight = isInitialWindow ? kInitialWindowHeight : this->height();

    fWindow = SDL_CreateWindow(this->getTitle(), SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
                               windowWidth, windowHeight, windowFlags);
    if (!fWindow) {
        report_sdl_error("Failed to create SDL window.");
        return;
    }
    fWindowMSAASampleCount = msaaSampleCount;
}

void SkOSWindow::destroyWindow() {
    this->detach();
    if (fWindow) {
        SDL_DestroyWindow(fWindow);
        fWindow = nullptr;
        fWindowMSAASampleCount = 0;
    }
}

bool SkOSWindow::HasDirtyWindows() {
    if (gCurrentWindow && gCurrentWindow->fWindow) {
        return gCurrentWindow->isDirty();
    }
    return false;
}

void SkOSWindow::UpdateDirtyWindows() {
    if (gCurrentWindow && gCurrentWindow->fWindow) {
        if (gCurrentWindow->isDirty()) {
            // This will call present.
            gCurrentWindow->update(nullptr);
        }
    }
}

void SkOSWindow::HandleEvent(const SDL_Event& event) {
    switch (event.type) {
        case SDL_MOUSEMOTION:
            if (SkOSWindow* window = GetInstanceForWindowID(event.motion.windowID)) {
                if (event.motion.state == SDL_PRESSED) {
                    window->handleClick(event.motion.x, event.motion.y,
                                        SkView::Click::kMoved_State, nullptr);
                }
            }
            break;
        case SDL_MOUSEBUTTONDOWN:
        case SDL_MOUSEBUTTONUP:
            if (SkOSWindow* window = GetInstanceForWindowID(event.button.windowID)) {
                window->handleClick(event.button.x, event.button.y,
                                    event.button.state == SDL_PRESSED ?
                                    SkView::Click::kDown_State :
                                    SkView::Click::kUp_State, nullptr);
            }
            break;
        case SDL_KEYDOWN:
            if (SkOSWindow* window = GetInstanceForWindowID(event.key.windowID)) {
                SDL_Keycode key = event.key.keysym.sym;
                SkKey sk = convert_sdlkey_to_skkey(key);
                if (kNONE_SkKey != sk) {
                    if (event.key.state == SDL_PRESSED) {
                        window->handleKey(sk);
                    } else {
                        window->handleKeyUp(sk);
                    }
                } else if (key == SDLK_ESCAPE) {
                    window->closeWindow();
                }
            }
            break;
        case SDL_TEXTINPUT:
            if (SkOSWindow* window = GetInstanceForWindowID(event.text.windowID)) {
                size_t len = strlen(event.text.text);
                for (size_t i = 0; i < len; i++) {
                    window->handleChar((SkUnichar)event.text.text[i]);
                }
            }
            break;
        case SDL_WINDOWEVENT:
            switch (event.window.event) {
                case SDL_WINDOWEVENT_SHOWN:
                    // For initialization purposes, we resize upon first show.
                    // Fallthrough.
                case SDL_WINDOWEVENT_SIZE_CHANGED:
                    if (SkOSWindow* window = GetInstanceForWindowID(event.window.windowID)) {
                        int w = 0;
                        int h = 0;
                        SDL_GetWindowSize(window->fWindow, &w, &h);
                        window->resize(w, h);
                    }
                    break;
                case SDL_WINDOWEVENT_FOCUS_GAINED:
                    if (GetInstanceForWindowID(event.text.windowID)) {
                        SDL_StartTextInput();
                    }
                    break;
                default:
                    break;
            }
            break;
        default:
            break;
    }
}

SkMSec gTimerDelay;

void SkOSWindow::RunEventLoop() {
    for (;;) {
        SkEvent::ServiceQueueTimer();
        bool hasMoreSkEvents = SkEvent::ProcessEvent();

        SDL_Event event;
        bool hasSDLEvents = SDL_PollEvent(&event) == 1;

        // Invalidations do not post to event loop, rather we just go through the
        // windows for each event loop iteration.
        bool hasDirtyWindows = HasDirtyWindows();

        if (!hasSDLEvents && !hasMoreSkEvents && !hasDirtyWindows) {
            // If there is no SDL events, SkOSWindow updates or SkEvents
            // to be done, wait for the SDL events.
            if (gTimerDelay > 0) {
                hasSDLEvents = SDL_WaitEventTimeout(&event, gTimerDelay) == 1;
            } else {
                hasSDLEvents = SDL_WaitEvent(&event) == 1;
            }
        }
        while (hasSDLEvents) {
            if (event.type == SDL_QUIT) {
                return;
            }
            HandleEvent(event);
            hasSDLEvents = SDL_PollEvent(&event);
        }
        UpdateDirtyWindows();
    }
}

void SkOSWindow::onSetTitle(const char title[]) {
    if (!fWindow) {
        return;
    }
    this->updateWindowTitle();
}

void SkOSWindow::updateWindowTitle() {
    SDL_SetWindowTitle(fWindow, this->getTitle());
}
///////////////////////////////////////////////////////////////////////////////////////

void SkEvent::SignalNonEmptyQueue() {
    // nothing to do, since we spin on our event-queue
}

void SkEvent::SignalQueueTimer(SkMSec delay) {
    gTimerDelay = delay;
}

//////////////////////////////////////////////////////////////////////////////////////////////

#include "SkApplication.h"
#include "SkEvent.h"
#include "SkWindow.h"

#if defined(SK_BUILD_FOR_ANDROID)
int SDL_main(int argc, char** argv) {
#else
int main(int argc, char** argv) {
#endif
    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS) != 0) {
        report_sdl_error("Failed to init SDL.");
        return -1;
    }

    application_init();

    SkOSWindow* window = create_sk_window(nullptr, argc, argv);

    // drain any events that occurred before |window| was assigned.
    while (SkEvent::ProcessEvent());

    SkOSWindow::RunEventLoop();

    delete window;
    application_term();

    SDL_Quit();

    return 0;
}