package com.mbien.opencl;

import com.mbien.opencl.CLDevice.Type;
import com.mbien.opencl.CLMemory.Mem;
import com.mbien.opencl.CLSampler.AddressingMode;
import com.mbien.opencl.CLSampler.FilteringMode;
import com.sun.gluegen.runtime.BufferFactory;
import com.sun.gluegen.runtime.CPU;
import com.sun.gluegen.runtime.PointerBuffer;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.DoubleBuffer;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;
import java.nio.LongBuffer;
import java.nio.ShortBuffer;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import static com.mbien.opencl.CLException.*;
import static com.sun.gluegen.runtime.BufferFactory.*;

/**
 * CLContext is responsible for managing objects such as command-queues, memory,
 * program and kernel objects and for executing kernels on one or more devices
 * specified in the context.
 * @author Michael Bien
 */
public class CLContext implements CLResource {

    final CL cl;
    public final long ID;

    protected CLDevice[] devices;

    protected final List<CLProgram> programs;
    protected final List<CLSampler> samplers;
    protected final List<CLMemory<? extends Buffer>> memoryObjects;
    protected final Map<CLDevice, List<CLCommandQueue>> queuesMap;


    protected CLContext(long contextID) {
        this.cl = CLPlatform.getLowLevelBinding();
        this.ID = contextID;
        this.programs = new ArrayList<CLProgram>();
        this.samplers = new ArrayList<CLSampler>();
        this.memoryObjects = new ArrayList<CLMemory<? extends Buffer>>();
        this.queuesMap = new HashMap<CLDevice, List<CLCommandQueue>>();
    }

    private final void initDevices() {
        
        if (devices == null) {

            int sizeofDeviceID = CPU.is32Bit() ? 4 : 8;
            PointerBuffer deviceCount = PointerBuffer.allocateDirect(1);

            int ret = cl.clGetContextInfo(ID, CL.CL_CONTEXT_DEVICES, 0, null, deviceCount);
            checkForError(ret, "can not enumerate devices");

            ByteBuffer deviceIDs = ByteBuffer.allocateDirect((int)deviceCount.get()).order(ByteOrder.nativeOrder());
            ret = cl.clGetContextInfo(ID, CL.CL_CONTEXT_DEVICES, deviceIDs.capacity(), deviceIDs, null);
            checkForError(ret, "can not enumerate devices");

            devices = new CLDevice[deviceIDs.capacity() / sizeofDeviceID];
            for (int i = 0; i < devices.length; i++) {
                devices[i] = new CLDevice(this, CPU.is32Bit() ? deviceIDs.getInt() : deviceIDs.getLong());
            }
        }
    }

    /**
     * Creates a context on all available devices (CL_DEVICE_TYPE_ALL).
     * The platform to be used is implementation dependent.
     */
    public static final CLContext create() {
        PointerBuffer properties = setupContextProperties(null);
        return new CLContext(createContextFromType(properties, CL.CL_DEVICE_TYPE_ALL));
    }

    /**
     * Creates a context on the specified device types.
     * The platform to be used is implementation dependent.
     */
    public static final CLContext create(CLDevice.Type... deviceTypes) {
        return create(null, deviceTypes);
    }

    /**
     * Creates a context on the specified devices.
     * The platform to be used is implementation dependent.
     */
    public static final CLContext create(CLDevice... devices) {
        return create(null, devices);
    }

    /**
     * Creates a context on the specified platform on all available devices (CL_DEVICE_TYPE_ALL).
     */
    public static final CLContext create(CLPlatform platform) {
        return create(platform, CLDevice.Type.ALL);
    }

    /**
     * Creates a context on the specified platform and with the specified
     * device types.
     */
    private static final CLContext create(CLPlatform platform, CLDevice.Type... deviceTypes) {

        long type = toDeviceBitmap(deviceTypes);

        PointerBuffer properties = setupContextProperties(platform);
        return new CLContext(createContextFromType(properties, type));
    }

    /**
     * Creates a context on the specified platform and with the specified
     * devices.
     */
    private static final CLContext create(CLPlatform platform, CLDevice[] devices) {

        PointerBuffer properties = setupContextProperties(platform);
        return new CLContext(createContext(properties, devices));
    }

    protected static final long createContextFromType(PointerBuffer properties, long deviceType) {

        IntBuffer status = IntBuffer.allocate(1);
        long context = CLPlatform.getLowLevelBinding().clCreateContextFromType(properties, deviceType, null, null, status);

        checkForError(status.get(), "can not create CL context");

        return context;
    }

    protected static final long createContext(PointerBuffer properties, CLDevice... devices) {

        IntBuffer status = BufferFactory.newDirectByteBuffer(4).asIntBuffer();
        PointerBuffer pb = null;
        if(devices != null && devices.length != 0) {
            pb = PointerBuffer.allocateDirect(devices.length);
            for (int i = 0; i < devices.length; i++) {
                pb.put(i, devices[i].ID);
            }
        }
        long context = CLPlatform.getLowLevelBinding().clCreateContext(properties, pb, null, null, status);

        checkForError(status.get(), "can not create CL context");

        return context;
    }

    private static final PointerBuffer setupContextProperties(CLPlatform platform) {

        if(platform == null) {
            platform = CLPlatform.getDefault();
        }
        
        if(platform == null) {
            throw new RuntimeException("no OpenCL installation found");
        }

        return PointerBuffer.allocateDirect(3).put(CL.CL_CONTEXT_PLATFORM)
                                              .put(platform.ID).put(0) // 0 terminated array
                                              .rewind();
    }

    /**
     * Creates a program from the given sources, the program is not build yet.
     */
    public CLProgram createProgram(String src) {
        CLProgram program = new CLProgram(this, src);
        programs.add(program);
        return program;
    }

    /**
     * Creates a program and reads the sources from stream, the program is not build yet.
     * @throws IOException when a IOException occurred while reading or closing the stream.
     */
    public CLProgram createProgram(InputStream sources) throws IOException {

        if(sources == null)
            throw new IllegalArgumentException("input stream for program sources must not be null");

        BufferedReader reader = new BufferedReader(new InputStreamReader(sources));
        StringBuilder sb = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null)
                sb.append(line).append("\n");
        } finally {
            sources.close();
        }

        return createProgram(sb.toString());
    }

    /**
     * Creates a program from the given binaries, the program is not build yet.
     * <br/>Creating a programm will fail if:<br/>
     * <ul>
     * <li>the submitted binaries are invalid or can not be loaded from the OpenCL driver</li>
     * <li>the binaries do not fitt to the CLDevices associated with this context</li>
     * <li>binaries are missing for one or more CLDevices</li>
     * </ul>
     */
    public CLProgram createProgram(Map<CLDevice, byte[]> binaries) {
        CLProgram program = new CLProgram(this, binaries);
        programs.add(program);
        return program;
    }

    /**
     * Creates a CLBuffer with the specified flags and element count. No flags creates a MEM.READ_WRITE buffer.
     */
    public final CLBuffer<ShortBuffer> createShortBuffer(int size, Mem... flags) {
        return createBuffer(newDirectByteBuffer(size*SIZEOF_SHORT).asShortBuffer(), flags);
    }

    /**
     * Creates a CLBuffer with the specified flags and element count. No flags creates a MEM.READ_WRITE buffer.
     */
    public final CLBuffer<IntBuffer> createIntBuffer(int size, Mem... flags) {
        return createBuffer(newDirectByteBuffer(size*SIZEOF_INT).asIntBuffer(), flags);
    }

    /**
     * Creates a CLBuffer with the specified flags and element count. No flags creates a MEM.READ_WRITE buffer.
     */
    public final CLBuffer<LongBuffer> createLongBuffer(int size, Mem... flags) {
        return createBuffer(newDirectByteBuffer(size*SIZEOF_LONG).asLongBuffer(), flags);
    }

    /**
     * Creates a CLBuffer with the specified flags and element count. No flags creates a MEM.READ_WRITE buffer.
     */
    public final CLBuffer<FloatBuffer> createFloatBuffer(int size, Mem... flags) {
        return createBuffer(newDirectByteBuffer(size*SIZEOF_FLOAT).asFloatBuffer(), flags);
    }

    /**
     * Creates a CLBuffer with the specified flags and element count. No flags creates a MEM.READ_WRITE buffer.
     */
    public final CLBuffer<DoubleBuffer> createDoubleBuffer(int size, Mem... flags) {
        return createBuffer(newDirectByteBuffer(size*SIZEOF_DOUBLE).asDoubleBuffer(), flags);
    }

    /**
     * Creates a CLBuffer with the specified flags and buffer size in bytes. No flags creates a MEM.READ_WRITE buffer.
     */
    public final CLBuffer<ByteBuffer> createByteBuffer(int size, Mem... flags) {
        return createByteBuffer(size, Mem.flagsToInt(flags));
    }

    /**
     * Creates a CLBuffer with the specified flags and buffer size in bytes.
     */
    public final CLBuffer<ByteBuffer> createByteBuffer(int size, int flags) {
        return createBuffer(newDirectByteBuffer(size), flags);
    }

    /**
     * Creates a CLBuffer with the specified flags. No flags creates a MEM.READ_WRITE buffer.
     */
    public final <B extends Buffer> CLBuffer<B> createBuffer(B directBuffer, Mem... flags) {
        return createBuffer(directBuffer, Mem.flagsToInt(flags));
    }

    /**
     * Creates a CLBuffer with the specified flags.
     */
    public final <B extends Buffer> CLBuffer<B> createBuffer(B directBuffer, int flags) {
        CLBuffer<B> buffer = CLBuffer.create(this, directBuffer, flags);
        memoryObjects.add(buffer);
        return buffer;
    }

    CLCommandQueue createCommandQueue(CLDevice device, long properties) {

        CLCommandQueue queue = new CLCommandQueue(this, device, properties);

        List<CLCommandQueue> list = queuesMap.get(device);
        if(list == null) {
            list = new ArrayList<CLCommandQueue>();
            queuesMap.put(device, list);
        }
        list.add(queue);

        return queue;
    }

    public CLSampler createSampler(AddressingMode addrMode, FilteringMode filtMode, boolean normalizedCoords) {
        CLSampler sampler = new CLSampler(this, addrMode, filtMode, normalizedCoords);
        samplers.add(sampler);
        return sampler;
    }

    void onProgramReleased(CLProgram program) {
        programs.remove(program);
    }

    void onMemoryReleased(CLMemory<?> buffer) {
        memoryObjects.remove(buffer);
    }

    void onCommandQueueReleased(CLDevice device, CLCommandQueue queue) {
        List<CLCommandQueue> list = queuesMap.get(device);
        list.remove(queue);
        // remove empty lists from map
        if(list.isEmpty())
            queuesMap.remove(device);
    }

    void onSamplerReleased(CLSampler sampler) {
        samplers.remove(sampler);
    }

    /**
     * Releases the context and all resources.
     */
    public void release() {

        //release all resources
        while(!programs.isEmpty())
            programs.get(0).release();

        while(!memoryObjects.isEmpty())
            memoryObjects.get(0).release();

        while(!samplers.isEmpty())
            samplers.get(0).release();

        for (CLDevice device : devices) {
            List<CLCommandQueue> list = queuesMap.get(device);
            if(list != null) {
                while(!list.isEmpty()) {
                    list.get(0).release();
                }
            }
        }

        int ret = cl.clReleaseContext(ID);
        checkForError(ret, "error releasing context");
    }

    /**
     * Returns a read only view of all programs associated with this context.
     */
    public List<CLProgram> getCLPrograms() {
        return Collections.unmodifiableList(programs);
    }

    /**
     * Returns a read only view of all allocated memory objects associated with this context.
     */
    public List<CLMemory<? extends Buffer>> getCLMemoryObjects() {
        return Collections.unmodifiableList(memoryObjects);
    }

    /**
     * Returns a read only view of all samplers associated with this context.
     */
    public List<CLSampler> getCLSamplers() {
        return Collections.unmodifiableList(samplers);
    }

    /**
     * Returns the device with maximal FLOPS from this context.
     * The device speed is estimated by calulating the product of
     * MAX_COMPUTE_UNITS and MAX_CLOCK_FREQUENCY.
     * @see #getMaxFlopsDevice(com.mbien.opencl.CLDevice.Type)
     */
    public CLDevice getMaxFlopsDevice() {
        return CLPlatform.findMaxFlopsDevice(getCLDevices());
    }

    /**
     * Returns the device with maximal FLOPS of the specified device type from this context.
     * The device speed is estimated by calculating the product of
     * MAX_COMPUTE_UNITS and MAX_CLOCK_FREQUENCY.
     */
    public CLDevice getMaxFlopsDevice(CLDevice.Type type) {
        return CLPlatform.findMaxFlopsDevice(getCLDevices(), type);
    }

    /**
     * Returns all devices associated with this CLContext.
     */
    public CLDevice[] getCLDevices() {
        initDevices();
        return devices;
    }

    CLDevice getCLDevice(long dID) {
        CLDevice[] deviceArray = getCLDevices();
        for (int i = 0; i < deviceArray.length; i++) {
            if(dID == deviceArray[i].ID)
                return deviceArray[i];
        }
        return null;
    }

    protected static long toDeviceBitmap(Type[] deviceTypes) {
        long type = 0;
        if (deviceTypes != null) {
            for (int i = 0; i < deviceTypes.length; i++) {
                type |= deviceTypes[i].TYPE;
            }
        }
        return type;
    }

    @Override
    public String toString() {
        return "CLContext [id: " + ID
                      + " #devices: " + getCLDevices().length
                      + "]";
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        final CLContext other = (CLContext) obj;
        if (this.ID != other.ID) {
            return false;
        }
        return true;
    }

    @Override
    public int hashCode() {
        int hash = 7;
        hash = 23 * hash + (int) (this.ID ^ (this.ID >>> 32));
        return hash;
    }

}