/*********************************************************************
 *
 * Copyright 2012 Intel Corporation
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy,
 * modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 *********************************************************************/

#include <assert.h>

#include <map>
#if defined(_MSC_VER)
#include <memory>
#else
#include <tr1/memory>
#endif

#include <gltrace.hpp>
#include <os_thread.hpp>

namespace gltrace {

typedef std::tr1::shared_ptr<Context> context_ptr_t;
static std::map<uintptr_t, context_ptr_t> context_map;
static os::recursive_mutex context_map_mutex;

class ThreadState {
public:
    context_ptr_t current_context;
    context_ptr_t dummy_context;     /*
                                      * For cases when there is no current
                                      * context, but the app still calls some
                                      * GL function that expects one.
                                      */
    ThreadState() : dummy_context(new Context)
    {
        current_context = dummy_context;
    }
};

static os::thread_specific_ptr<struct ThreadState> thread_state;

static ThreadState *get_ts(void)
{
    ThreadState *ts = thread_state.get();

    if (!ts) {
        ts = new ThreadState;
        thread_state.reset(ts);
    }

    return ts;
}

static void _retainContext(context_ptr_t ctx)
{
    ctx->retain_count++;
}

void retainContext(uintptr_t context_id)
{
    context_map_mutex.lock();
    if (context_map.find(context_id) != context_map.end())
        _retainContext(context_map[context_id]);
    context_map_mutex.unlock();
}

static bool _releaseContext(context_ptr_t ctx)
{
    return !(--ctx->retain_count);
}

/*
 * return true if the context was destroyed, false if only its refcount
 * got decreased. Note that even if the context was destroyed it may
 * still live, if it's the currently selected context (by setContext).
 */
bool releaseContext(uintptr_t context_id)
{
    bool res;

    context_map_mutex.lock();
    /*
     * This can potentially called (from glX) with an invalid context_id,
     * so don't assert on it being valid.
     */
    if (context_map.find(context_id) != context_map.end()) {
        res = _releaseContext(context_map[context_id]);
        if (res)
            context_map.erase(context_id);
    }
    context_map_mutex.unlock();

    return res;
}

void createContext(uintptr_t context_id)
{
    // wglCreateContextAttribsARB causes internal calls to wglCreateContext to be
    // traced, causing context to be defined twice.
    if (context_map.find(context_id) != context_map.end()) {
        return;
    }

    context_ptr_t ctx(new Context);

    context_map_mutex.lock();

    _retainContext(ctx);
    context_map[context_id] = ctx;

    context_map_mutex.unlock();
}

void setContext(uintptr_t context_id)
{
    ThreadState *ts = get_ts();
    context_ptr_t ctx;

    context_map_mutex.lock();

    assert(context_map.find(context_id) != context_map.end());
    ctx = context_map[context_id];

    context_map_mutex.unlock();

    ts->current_context = ctx;
}

void clearContext(void)
{
    ThreadState *ts = get_ts();

    ts->current_context = ts->dummy_context;
}

Context *getContext(void)
{
    return get_ts()->current_context.get();
}

}
