/*****************************************************************
|
|   Neptune - HTTP Protocol
|
| Copyright (c) 2002-2008, Axiomatic Systems, LLC.
| All rights reserved.
|
| Redistribution and use in source and binary forms, with or without
| modification, are permitted provided that the following conditions are met:
|     * Redistributions of source code must retain the above copyright
|       notice, this list of conditions and the following disclaimer.
|     * 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.
|     * Neither the name of Axiomatic Systems nor the
|       names of its contributors may be used to endorse or promote products
|       derived from this software without specific prior written permission.
|
| THIS SOFTWARE IS PROVIDED BY AXIOMATIC SYSTEMS ''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 AXIOMATIC SYSTEMS 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.
|
 ****************************************************************/

#ifndef _NPT_HTTP_H_
#define _NPT_HTTP_H_

/*----------------------------------------------------------------------
|   includes
+---------------------------------------------------------------------*/
#include "NptUri.h"
#include "NptTypes.h"
#include "NptList.h"
#include "NptBufferedStreams.h"
#include "NptSockets.h"
#include "NptMap.h"
#include "NptDynamicCast.h"
#include "NptVersion.h"
#include "NptTime.h"
#include "NptThreads.h"
#include "NptAutomaticCleaner.h"

/*----------------------------------------------------------------------
|   constants
+---------------------------------------------------------------------*/
const unsigned int NPT_HTTP_DEFAULT_PORT  = 80;
const unsigned int NPT_HTTPS_DEFAULT_PORT = 443;
const unsigned int NPT_HTTP_INVALID_PORT  = 0;

const NPT_Timeout  NPT_HTTP_CLIENT_DEFAULT_CONNECTION_TIMEOUT    = 30000;
const NPT_Timeout  NPT_HTTP_CLIENT_DEFAULT_IO_TIMEOUT            = 30000;
const NPT_Timeout  NPT_HTTP_CLIENT_DEFAULT_NAME_RESOLVER_TIMEOUT = 60000;
const unsigned int NPT_HTTP_CLIENT_DEFAULT_MAX_REDIRECTS         = 20;

const NPT_Timeout NPT_HTTP_SERVER_DEFAULT_CONNECTION_TIMEOUT    = NPT_TIMEOUT_INFINITE;
const NPT_Timeout NPT_HTTP_SERVER_DEFAULT_IO_TIMEOUT            = 60000;

const unsigned int NPT_HTTP_CONNECTION_MANAGER_MAX_CONNECTION_POOL_SIZE = 5;
const unsigned int NPT_HTTP_CONNECTION_MANAGER_MAX_CONNECTION_AGE       = 30; // seconds
const unsigned int NPT_HTTP_MAX_RECONNECTS                              = 10;
const unsigned int NPT_HTTP_MAX_100_RESPONSES                           = 10;

const int NPT_HTTP_PROTOCOL_MAX_LINE_LENGTH  = 8192;
const int NPT_HTTP_PROTOCOL_MAX_HEADER_COUNT = 100;

#define NPT_HTTP_PROTOCOL_1_0   "HTTP/1.0"
#define NPT_HTTP_PROTOCOL_1_1   "HTTP/1.1"
#define NPT_HTTP_METHOD_GET     "GET"
#define NPT_HTTP_METHOD_HEAD    "HEAD"
#define NPT_HTTP_METHOD_POST    "POST"
#define NPT_HTTP_METHOD_PUT     "PUT"
#define NPT_HTTP_METHOD_OPTIONS "OPTIONS"
#define NPT_HTTP_METHOD_DELETE  "DELETE"
#define NPT_HTTP_METHOD_TRACE   "TRACE"

#define NPT_HTTP_HEADER_HOST                "Host"
#define NPT_HTTP_HEADER_CONNECTION          "Connection"
#define NPT_HTTP_HEADER_USER_AGENT          "User-Agent"
#define NPT_HTTP_HEADER_SERVER              "Server"
#define NPT_HTTP_HEADER_CONTENT_LENGTH      "Content-Length"
#define NPT_HTTP_HEADER_CONTENT_TYPE        "Content-Type"
#define NPT_HTTP_HEADER_CONTENT_ENCODING    "Content-Encoding"
#define NPT_HTTP_HEADER_TRANSFER_ENCODING   "Transfer-Encoding"
#define NPT_HTTP_HEADER_LOCATION            "Location"
#define NPT_HTTP_HEADER_RANGE               "Range"
#define NPT_HTTP_HEADER_CONTENT_RANGE       "Content-Range"
#define NPT_HTTP_HEADER_COOKIE              "Cookie"
#define NPT_HTTP_HEADER_ACCEPT_RANGES       "Accept-Ranges"
#define NPT_HTTP_HEADER_CONTENT_RANGE       "Content-Range"
#define NPT_HTTP_HEADER_AUTHORIZATION       "Authorization"

#define NPT_HTTP_TRANSFER_ENCODING_CHUNKED  "chunked"


const int NPT_ERROR_HTTP_INVALID_RESPONSE_LINE = NPT_ERROR_BASE_HTTP - 0;
const int NPT_ERROR_HTTP_INVALID_REQUEST_LINE  = NPT_ERROR_BASE_HTTP - 1;
const int NPT_ERROR_HTTP_NO_PROXY              = NPT_ERROR_BASE_HTTP - 2;
const int NPT_ERROR_HTTP_INVALID_REQUEST       = NPT_ERROR_BASE_HTTP - 3;
const int NPT_ERROR_HTTP_METHOD_NOT_SUPPORTED  = NPT_ERROR_BASE_HTTP - 4;
const int NPT_ERROR_HTTP_TOO_MANY_REDIRECTS    = NPT_ERROR_BASE_HTTP - 5;
const int NPT_ERROR_HTTP_TOO_MANY_RECONNECTS   = NPT_ERROR_BASE_HTTP - 6;
const int NPT_ERROR_HTTP_CANNOT_RESEND_BODY    = NPT_ERROR_BASE_HTTP - 7;

#define NPT_HTTP_LINE_TERMINATOR "\r\n"

#if !defined(NPT_CONFIG_HTTP_DEFAULT_USER_AGENT)
#define NPT_CONFIG_HTTP_DEFAULT_USER_AGENT "Neptune/" NPT_NEPTUNE_VERSION_STRING
#endif

/*----------------------------------------------------------------------
|   types
+---------------------------------------------------------------------*/
typedef unsigned int NPT_HttpStatusCode;
typedef NPT_UrlQuery NPT_HttpUrlQuery; // for backward compatibility

/*----------------------------------------------------------------------
|   NPT_HttpUrl
+---------------------------------------------------------------------*/
class NPT_HttpUrl : public NPT_Url {
public:
    // constructors
    NPT_HttpUrl() {}
    NPT_HttpUrl(const char* host, 
                NPT_UInt16  port, 
                const char* path,
                const char* query = NULL,
                const char* fragment = NULL);
    NPT_HttpUrl(const char* url, bool ignore_scheme = false);

    // methods
    NPT_String ToString(bool with_fragment = true) const override;
};

/*----------------------------------------------------------------------
|   NPT_HttpProtocol
+---------------------------------------------------------------------*/
class NPT_HttpProtocol
{
public:
    // class methods
    const char* GetStatusCodeString(NPT_HttpStatusCode status_code);
};

/*----------------------------------------------------------------------
|   NPT_HttpHeader
+---------------------------------------------------------------------*/
class NPT_HttpHeader {
public:
    // constructors and destructor
    NPT_HttpHeader(const char* name, const char* value);
    ~NPT_HttpHeader();

    // methods
    NPT_Result        Emit(NPT_OutputStream& stream) const;
    const NPT_String& GetName()  const { return m_Name;  }
    const NPT_String& GetValue() const { return m_Value; }
    NPT_Result        SetName(const char* name);
    NPT_Result        SetValue(const char* value);

private:
    // members
    NPT_String m_Name;
    NPT_String m_Value;
};

/*----------------------------------------------------------------------
|   NPT_HttpHeaders
+---------------------------------------------------------------------*/
class NPT_HttpHeaders {
public:
    // constructors and destructor
     NPT_HttpHeaders();
    ~NPT_HttpHeaders();

    // methods
    NPT_Result Parse(NPT_BufferedInputStream& stream);
    NPT_Result Emit(NPT_OutputStream& stream) const;
    const NPT_List<NPT_HttpHeader*>& GetHeaders() const { return m_Headers; }
    NPT_HttpHeader*   GetHeader(const char* name) const;
    const NPT_String* GetHeaderValue(const char* name) const;
    NPT_Result        SetHeader(const char* name, const char* value, bool replace=true);
    NPT_Result        AddHeader(const char* name, const char* value);
    NPT_Result        RemoveHeader(const char* name);

private:
    // members
    NPT_List<NPT_HttpHeader*> m_Headers;
};

/*----------------------------------------------------------------------
|   NPT_HttpEntity
+---------------------------------------------------------------------*/
class NPT_HttpEntity {
public:
    // constructors and destructor
             NPT_HttpEntity();
             NPT_HttpEntity(const NPT_HttpHeaders& headers);
    virtual ~NPT_HttpEntity();

    // methods
    NPT_Result SetInputStream(const NPT_InputStreamReference& stream,
                              bool update_content_length = false);
    NPT_Result SetInputStream(const void* data, NPT_Size size);
    NPT_Result SetInputStream(const NPT_String& string);
    NPT_Result SetInputStream(const char* string);
    NPT_Result GetInputStream(NPT_InputStreamReference& stream);
    NPT_Result Load(NPT_DataBuffer& buffer);
    NPT_Result SetHeaders(const NPT_HttpHeaders& headers);

    // field access
    NPT_Result        SetContentLength(NPT_LargeSize length);
    NPT_Result        SetContentType(const char* type);
    NPT_Result        SetContentEncoding(const char* encoding);
    NPT_Result        SetTransferEncoding(const char* encoding);
    NPT_LargeSize     GetContentLength()     { return m_ContentLength;   }
    const NPT_String& GetContentType()       { return m_ContentType;     }
    const NPT_String& GetContentEncoding()   { return m_ContentEncoding; }
    const NPT_String& GetTransferEncoding()  { return m_TransferEncoding;}
    bool              ContentLengthIsKnown() { return m_ContentLengthIsKnown; }

private:
    // members
    NPT_InputStreamReference m_InputStream;
    NPT_LargeSize            m_ContentLength;
    NPT_String               m_ContentType;
    NPT_String               m_ContentEncoding;
    NPT_String               m_TransferEncoding;
    bool                     m_ContentLengthIsKnown;
};

/*----------------------------------------------------------------------
|   NPT_HttpMessage
+---------------------------------------------------------------------*/
class NPT_HttpMessage {
public:
    // constructors and destructor
    virtual ~NPT_HttpMessage();

    // methods
    const NPT_String& GetProtocol() const { 
        return m_Protocol; 
    }
    NPT_Result SetProtocol(const char* protocol) {
        m_Protocol = protocol;
        return NPT_SUCCESS;
    }
    NPT_HttpHeaders& GetHeaders() { 
        return m_Headers;  
    }
    const NPT_HttpHeaders& GetHeaders() const { 
        return m_Headers;  
    }
    NPT_Result SetEntity(NPT_HttpEntity* entity);
    NPT_HttpEntity* GetEntity() {
        return m_Entity;
    }
    NPT_HttpEntity* GetEntity() const {
        return m_Entity;
    }
    virtual NPT_Result ParseHeaders(NPT_BufferedInputStream& stream);

protected:
    // constructors
    NPT_HttpMessage(const char* protocol);

    // members
    NPT_String      m_Protocol;
    NPT_HttpHeaders m_Headers;
    NPT_HttpEntity* m_Entity;
};

/*----------------------------------------------------------------------
|   NPT_HttpRequest
+---------------------------------------------------------------------*/
class NPT_HttpRequest : public NPT_HttpMessage {
public:
    // class methods
    static NPT_Result Parse(NPT_BufferedInputStream& stream, 
                            const NPT_SocketAddress* endpoint,
                            NPT_HttpRequest*&        request);

    // constructors and destructor
    NPT_HttpRequest(const NPT_HttpUrl& url,
                    const char*        method,
                    const char*        protocol = NPT_HTTP_PROTOCOL_1_0);
    NPT_HttpRequest(const char*        url,
                    const char*        method,
                    const char*        protocol = NPT_HTTP_PROTOCOL_1_0);
    ~NPT_HttpRequest() override;

    // methods
    const NPT_HttpUrl& GetUrl() const { return m_Url; }
    NPT_HttpUrl&       GetUrl()       { return m_Url; }
    NPT_Result         SetUrl(const char* url);
    NPT_Result         SetUrl(const NPT_HttpUrl& url);
    const NPT_String&  GetMethod() const { return m_Method; }
    virtual NPT_Result Emit(NPT_OutputStream& stream, bool use_proxy=false) const;
    
protected:
    // members
    NPT_HttpUrl m_Url;
    NPT_String  m_Method;
};

/*----------------------------------------------------------------------
|   NPT_HttpResponse
+---------------------------------------------------------------------*/
class NPT_HttpResponse : public NPT_HttpMessage {
public:
    // class methods
    static NPT_Result Parse(NPT_BufferedInputStream& stream, 
                            NPT_HttpResponse*&       response);

    // constructors and destructor
             NPT_HttpResponse(NPT_HttpStatusCode status_code,
                              const char*        reason_phrase,
                              const char*        protocol = NPT_HTTP_PROTOCOL_1_0);
    ~NPT_HttpResponse() override;

    // methods
    NPT_Result         SetStatus(NPT_HttpStatusCode status_code,
                                 const char*        reason_phrase,
                                 const char*        protocol = NULL);
    NPT_Result         SetProtocol(const char* protocol);
    NPT_HttpStatusCode GetStatusCode() const { return m_StatusCode;   }
    const NPT_String&  GetReasonPhrase() const { return m_ReasonPhrase; }
    virtual NPT_Result Emit(NPT_OutputStream& stream) const;

protected:
    // members
    NPT_HttpStatusCode m_StatusCode;
    NPT_String         m_ReasonPhrase;
};

/*----------------------------------------------------------------------
|   NPT_HttpProxyAddress
+---------------------------------------------------------------------*/
class NPT_HttpProxyAddress
{
public:
    NPT_HttpProxyAddress() : m_Port(NPT_HTTP_INVALID_PORT) {}
    NPT_HttpProxyAddress(const char* hostname, NPT_UInt16 port) :
        m_HostName(hostname), m_Port(port) {}

    const NPT_String& GetHostName() const { return m_HostName; } 
    void              SetHostName(const char* hostname) { m_HostName = hostname; }
    NPT_UInt16        GetPort() const { return m_Port; }
    void              SetPort(NPT_UInt16 port) { m_Port = port; }

private:
    NPT_String m_HostName;
    NPT_UInt16 m_Port;
};

/*----------------------------------------------------------------------
|   NPT_HttpProxySelector
+---------------------------------------------------------------------*/
class NPT_HttpProxySelector
{
public:
    // class methods
    static NPT_HttpProxySelector* GetDefault();
    static NPT_HttpProxySelector* GetSystemSelector();
    
    // methods
    virtual ~NPT_HttpProxySelector() {};
    virtual NPT_Result GetProxyForUrl(const NPT_HttpUrl& url, NPT_HttpProxyAddress& proxy) = 0;
    
private:
    // class members
    static NPT_HttpProxySelector* m_SystemDefault;
};

class NPT_HttpRequestContext;

/*----------------------------------------------------------------------
|   NPT_HttpClient
+---------------------------------------------------------------------*/
class NPT_HttpClient {
public:
    // types
    struct Config {
        Config() : m_ConnectionTimeout(  NPT_HTTP_CLIENT_DEFAULT_CONNECTION_TIMEOUT),
                   m_IoTimeout(          NPT_HTTP_CLIENT_DEFAULT_CONNECTION_TIMEOUT),
                   m_NameResolverTimeout(NPT_HTTP_CLIENT_DEFAULT_NAME_RESOLVER_TIMEOUT),
                   m_MaxRedirects(       NPT_HTTP_CLIENT_DEFAULT_MAX_REDIRECTS),
                   m_UserAgent(          NPT_CONFIG_HTTP_DEFAULT_USER_AGENT) {}
        NPT_Timeout  m_ConnectionTimeout;
        NPT_Timeout  m_IoTimeout;
        NPT_Timeout  m_NameResolverTimeout;
        NPT_Cardinal m_MaxRedirects;
        NPT_String   m_UserAgent;
    };
    
    class Connection {
    public:
        virtual ~Connection() {}
        virtual NPT_InputStreamReference&  GetInputStream()  = 0;
        virtual NPT_OutputStreamReference& GetOutputStream() = 0;
        virtual NPT_Result                 GetInfo(NPT_SocketInfo& info) = 0;
        virtual bool                       SupportsPersistence() { return false;                    }
        virtual bool                       IsRecycled()          { return false;                    }
        virtual NPT_Result                 Recycle()             { delete this; return NPT_SUCCESS; }
        virtual NPT_Result                 Abort()               { return NPT_ERROR_NOT_IMPLEMENTED; }
    };
    
    class Connector {
    public:
        virtual ~Connector() {}

        virtual NPT_Result Connect(const NPT_HttpUrl&          url,
                                   NPT_HttpClient&             client,
                                   const NPT_HttpProxyAddress* proxy,
                                   bool                        reuse, // whether we can reuse a connection or not
                                   Connection*&                connection) = 0;
        
    protected:
        NPT_Result TrackConnection(NPT_HttpClient& client,
                                   Connection*     connection) { return client.TrackConnection(connection); }
        Connector() {} // don't instantiate directly
    };

    // class methods
    static NPT_Result WriteRequest(NPT_OutputStream& output_stream, 
                                   NPT_HttpRequest&  request,
                                   bool              should_persist,
                                   bool			     use_proxy = false);
    static NPT_Result ReadResponse(NPT_InputStreamReference&  input_stream,
                                   bool                       should_persist,
                                   bool                       expect_entity,
                                   NPT_HttpResponse*&         response,
                                   NPT_Reference<Connection>* cref = NULL);

    /**
     * @param connector Pointer to a connector instance, or NULL to use 
     * the default (TCP) connector.
     * @param transfer_ownership Boolean flag. If true, the NPT_HttpClient object
     * becomes the owner of the passed Connector and will delete it when it is 
     * itself deleted. If false, the caller keeps the ownership of the connector. 
     * This flag is ignored if the connector parameter is NULL.
     */
    NPT_HttpClient(Connector* connector = NULL, bool transfer_ownership = true);

    virtual ~NPT_HttpClient();

    // methods
    NPT_Result SendRequest(NPT_HttpRequest&        request,
                           NPT_HttpResponse*&      response,
                           NPT_HttpRequestContext* context = NULL);
    NPT_Result Abort();
    const Config& GetConfig() const { return m_Config; }
    NPT_Result SetConfig(const Config& config);
    NPT_Result SetProxy(const char* http_proxy_hostname, 
                        NPT_UInt16  http_proxy_port,
                        const char* https_proxy_hostname = NULL,
                        NPT_UInt16  https_proxy_port = 0);
    NPT_Result SetProxySelector(NPT_HttpProxySelector* selector);
    NPT_Result SetConnector(Connector* connector);
    NPT_Result SetTimeouts(NPT_Timeout connection_timeout,
                           NPT_Timeout io_timeout,
                           NPT_Timeout name_resolver_timeout);
    NPT_Result SetUserAgent(const char* user_agent);
    NPT_Result SetOptions(NPT_Flags options, bool on);
    
protected:
    // methods
    NPT_Result TrackConnection(Connection* connection);
    NPT_Result SendRequestOnce(NPT_HttpRequest&        request,
                               NPT_HttpResponse*&      response,
                               NPT_HttpRequestContext* context = NULL);

    // members
    Config                 m_Config;
    NPT_HttpProxySelector* m_ProxySelector;
    bool                   m_ProxySelectorIsOwned;
    Connector*             m_Connector;
    bool                   m_ConnectorIsOwned;
    NPT_Mutex              m_AbortLock;
    bool                   m_Aborted;
};

/*----------------------------------------------------------------------
|   NPT_HttpConnectionManager
+---------------------------------------------------------------------*/
class NPT_HttpConnectionManager : public NPT_Thread,
                                  public NPT_AutomaticCleaner::Singleton
{
public:
    // singleton management
    static NPT_HttpConnectionManager* GetInstance();
    
    class Connection : public NPT_HttpClient::Connection 
    {
    public:
        Connection(NPT_HttpConnectionManager& manager,
                   NPT_SocketReference&       socket,
                   NPT_InputStreamReference   input_stream,
                   NPT_OutputStreamReference  output_stream);
        ~Connection() override;
                   
        // NPT_HttpClient::Connection methods
        NPT_InputStreamReference&  GetInputStream() override      { return m_InputStream;           }
        NPT_OutputStreamReference& GetOutputStream() override     { return m_OutputStream;          }
        NPT_Result                 GetInfo(NPT_SocketInfo& info) override { return m_Socket->GetInfo(info); }
        bool                       SupportsPersistence() override { return true;                    }
        bool                       IsRecycled() override          { return m_IsRecycled;            }
        NPT_Result                 Recycle() override;
        NPT_Result                 Abort() override               { return m_Socket->Cancel(); }

        // members
        NPT_HttpConnectionManager& m_Manager;
        bool                       m_IsRecycled;
        NPT_TimeStamp              m_TimeStamp;
        NPT_SocketReference        m_Socket;
        NPT_InputStreamReference   m_InputStream;
        NPT_OutputStreamReference  m_OutputStream;
    };
    
    // destructor
    ~NPT_HttpConnectionManager() override;
    
    // methods
    Connection* FindConnection(NPT_SocketAddress& address);
    NPT_Result  Recycle(Connection* connection);
    NPT_Result  Track(NPT_HttpClient* client, NPT_HttpClient::Connection* connection);
    NPT_Result  AbortConnections(NPT_HttpClient* client);
    
    // class methods
    static NPT_Result  Untrack(NPT_HttpClient::Connection* connection);
    
private:
    typedef NPT_List<NPT_HttpClient::Connection*> ConnectionList;
    
    // class members
    static NPT_HttpConnectionManager* Instance;
    
    // constructor
    NPT_HttpConnectionManager();
    
    // NPT_Thread methods
    void Run() override;
    
    // methods
    NPT_Result      UntrackConnection(NPT_HttpClient::Connection* connection);
    NPT_Result      Cleanup();

    // members
    NPT_Mutex             m_Lock;
    NPT_Cardinal          m_MaxConnections;
    NPT_Cardinal          m_MaxConnectionAge;
    NPT_SharedVariable    m_Aborted;
    NPT_List<Connection*> m_Connections;
    NPT_Map<NPT_HttpClient*, ConnectionList> m_ClientConnections;
};

/*----------------------------------------------------------------------
|   NPT_HttpRequestContext
+---------------------------------------------------------------------*/
class NPT_HttpRequestContext
{
public:
    // constructor
    NPT_HttpRequestContext() {}
    NPT_HttpRequestContext(const NPT_SocketAddress* local_address,
                           const NPT_SocketAddress* remote_address);
                  
    // methods
    const NPT_SocketAddress& GetLocalAddress()  const { return m_LocalAddress;  }
    const NPT_SocketAddress& GetRemoteAddress() const { return m_RemoteAddress; }
    void SetLocalAddress(const NPT_SocketAddress& address) {
        m_LocalAddress = address;
    }
    void SetRemoteAddress(const NPT_SocketAddress& address) {
        m_RemoteAddress = address;
    }
    
private:
    // members
    NPT_SocketAddress m_LocalAddress;
    NPT_SocketAddress m_RemoteAddress;
};

/*----------------------------------------------------------------------
|   NPT_HttpRequestHandler
+---------------------------------------------------------------------*/
class NPT_HttpRequestHandler 
{
public:
    NPT_IMPLEMENT_DYNAMIC_CAST(NPT_HttpRequestHandler)

    // destructor
    virtual ~NPT_HttpRequestHandler() {}

    // methods
    virtual NPT_Result SetupResponse(NPT_HttpRequest&              request,
                                     const NPT_HttpRequestContext& context,
                                     NPT_HttpResponse&             response) = 0;
                                     
    /**
     * Override this method if you want to write the body yourself.
     * The default implementation will simply write out the entity's
     * input stream.
     */
    virtual NPT_Result SendResponseBody(const NPT_HttpRequestContext& context,
                                        NPT_HttpResponse&             response,
                                        NPT_OutputStream&             output);
    
    /**
     * A notification method called by the server upon completing the 
     * processing of a request.
     */
    virtual void Completed(NPT_Result /*result*/) {}
};

/*----------------------------------------------------------------------
|   NPT_HttpStaticRequestHandler
+---------------------------------------------------------------------*/
class NPT_HttpStaticRequestHandler : public NPT_HttpRequestHandler
{
public:
    // constructors
    NPT_HttpStaticRequestHandler(const char* document, 
                                 const char* mime_type = "text/html",
                                 bool        copy = true);
    NPT_HttpStaticRequestHandler(const void* data,
                                 NPT_Size    size,
                                 const char* mime_type = "text/html",
                                 bool        copy = true);

    // NPT_HttpRequestHandler methods
    NPT_Result SetupResponse(NPT_HttpRequest&              request, 
                                     const NPT_HttpRequestContext& context,
                                     NPT_HttpResponse&             response) override;

private:
    NPT_String     m_MimeType;
    NPT_DataBuffer m_Buffer;
};

/*----------------------------------------------------------------------
|   NPT_HttpFileRequestHandler_DefaultFileTypeMapEntry
+---------------------------------------------------------------------*/
typedef struct NPT_HttpFileRequestHandler_DefaultFileTypeMapEntry {
    const char* extension;
    const char* mime_type;
} NPT_HttpFileRequestHandler_FileTypeMapEntry;

/*----------------------------------------------------------------------
|   NPT_HttpFileRequestHandler
+---------------------------------------------------------------------*/
class NPT_HttpFileRequestHandler : public NPT_HttpRequestHandler
{
public:
    // constructors
    NPT_HttpFileRequestHandler(const char* url_root,
                               const char* file_root,
                               bool        auto_dir = false,
                               const char* auto_index = NULL);

    // NPT_HttpRequestHandler methods
    NPT_Result SetupResponse(NPT_HttpRequest&              request, 
                                     const NPT_HttpRequestContext& context,
                                     NPT_HttpResponse&             response) override;
    
    // class methods
    static const char* GetDefaultContentType(const char* extension);
    
    // accessors
    NPT_Map<NPT_String,NPT_String>& GetFileTypeMap() { return m_FileTypeMap; }
    void SetDefaultMimeType(const char* mime_type) {
        m_DefaultMimeType = mime_type;
    }
    void SetUseDefaultFileTypeMap(bool use_default) {
        m_UseDefaultFileTypeMap = use_default;
    }
    
    static NPT_Result SetupResponseBody(NPT_HttpResponse&         response,
                                        NPT_InputStreamReference& stream,
                                        const NPT_String*         range_spec = NULL);

protected:
    // methods
    const char* GetContentType(const NPT_String& filename);

private:
    NPT_String                      m_UrlRoot;
    NPT_String                      m_FileRoot;
    NPT_Map<NPT_String, NPT_String> m_FileTypeMap;
    NPT_String                      m_DefaultMimeType;
    bool                            m_UseDefaultFileTypeMap;
    bool                            m_AutoDir;
    NPT_String                      m_AutoIndex;
};

/*----------------------------------------------------------------------
|   NPT_HttpServer
+---------------------------------------------------------------------*/
class NPT_HttpServer {
public:
    // types
    struct Config {
        NPT_Timeout   m_ConnectionTimeout;
        NPT_Timeout   m_IoTimeout;
        NPT_IpAddress m_ListenAddress;
        NPT_UInt16    m_ListenPort;
        bool          m_ReuseAddress;
    };

    // constructors and destructor
    NPT_HttpServer(NPT_UInt16 listen_port = NPT_HTTP_DEFAULT_PORT, bool cancellable = false);
    NPT_HttpServer(NPT_IpAddress listen_address, 
                   NPT_UInt16    listen_port = NPT_HTTP_DEFAULT_PORT,
                   bool          cancellable = false);
    virtual ~NPT_HttpServer();

    // methods
    NPT_Result SetConfig(const Config& config);
    const Config& GetConfig() const { return m_Config; }
    NPT_Result SetListenPort(NPT_UInt16 port, bool reuse_address = true);
    NPT_Result SetTimeouts(NPT_Timeout connection_timeout, NPT_Timeout io_timeout);
    NPT_Result SetServerHeader(const char* server_header);
    NPT_Result Abort();
    NPT_Result WaitForNewClient(NPT_InputStreamReference&  input,
                                NPT_OutputStreamReference& output,
                                NPT_HttpRequestContext*    context,
                                NPT_Flags                  socket_flags = 0);
    NPT_Result Loop(bool cancellable_sockets=true);
    NPT_UInt16 GetPort() { return m_BoundPort; }
    void Terminate();
    
    /**
     * Add a request handler. By default the ownership of the handler is NOT transfered to this object,
     * so the caller is responsible for the lifetime management of the handler object.
     */
    virtual NPT_Result AddRequestHandler(NPT_HttpRequestHandler* handler, 
                                         const char*             path, 
                                         bool                    include_children = false,
                                         bool                    transfer_ownership = false);
    virtual NPT_HttpRequestHandler* FindRequestHandler(NPT_HttpRequest& request);
    virtual NPT_List<NPT_HttpRequestHandler*> FindRequestHandlers(NPT_HttpRequest& request);

    /**
     * Parse the request from a new client, form a response, and send it back. 
     */
    virtual NPT_Result RespondToClient(NPT_InputStreamReference&     input,
                                       NPT_OutputStreamReference&    output,
                                       const NPT_HttpRequestContext& context);

protected:
    // types
    struct HandlerConfig {
        HandlerConfig(NPT_HttpRequestHandler* handler,
                      const char*             path,
                      bool                    include_children,
                      bool                    transfer_ownership = false);
        ~HandlerConfig();

        // methods
        bool WillHandle(NPT_HttpRequest& request);

        // members
        NPT_HttpRequestHandler* m_Handler;
        NPT_String              m_Path;
        bool                    m_IncludeChildren;
        bool                    m_HandlerIsOwned;
    };

    // methods
    NPT_Result Bind();

    // members
    NPT_TcpServerSocket      m_Socket;
    NPT_UInt16               m_BoundPort;
    Config                   m_Config;
    NPT_List<HandlerConfig*> m_RequestHandlers;
    NPT_String               m_ServerHeader;
    bool                     m_Run;
};

/*----------------------------------------------------------------------
|   NPT_HttpResponder
+---------------------------------------------------------------------*/
class NPT_HttpResponder {
public:
    // types
    struct Config {
        NPT_Timeout m_IoTimeout;
    };

    // constructors and destructor
    NPT_HttpResponder(NPT_InputStreamReference&  input,
                      NPT_OutputStreamReference& output);
    virtual ~NPT_HttpResponder();

    // methods
    NPT_Result SetConfig(const Config& config);
    NPT_Result SetTimeout(NPT_Timeout io_timeout);
    NPT_Result ParseRequest(NPT_HttpRequest*&        request,
                            const NPT_SocketAddress* local_address = NULL);
    NPT_Result SendResponseHeaders(NPT_HttpResponse& response);

protected:
    // members
    Config                           m_Config;
    NPT_BufferedInputStreamReference m_Input;
    NPT_OutputStreamReference        m_Output;
};

/*----------------------------------------------------------------------
|   NPT_HttpChunkedInputStream
+---------------------------------------------------------------------*/
class NPT_HttpChunkedInputStream : public NPT_InputStream
{
public:
    // constructors and destructor
    NPT_HttpChunkedInputStream(NPT_BufferedInputStreamReference& stream);
    ~NPT_HttpChunkedInputStream() override;

    // NPT_InputStream methods
    NPT_Result Read(void*     buffer, 
                    NPT_Size  bytes_to_read, 
                    NPT_Size* bytes_read = NULL) override;
    NPT_Result Seek(NPT_Position offset) override;
    NPT_Result Tell(NPT_Position& offset) override;
    NPT_Result GetSize(NPT_LargeSize& size) override;
    NPT_Result GetAvailable(NPT_LargeSize& available) override;

protected:
    // members
    NPT_BufferedInputStreamReference m_Source;
    NPT_UInt32                       m_CurrentChunkSize;
    bool                             m_Eos;
};

/*----------------------------------------------------------------------
|   NPT_HttpChunkedOutputStream
+---------------------------------------------------------------------*/
class NPT_HttpChunkedOutputStream : public NPT_OutputStream
{
public:
    // constructors and destructor
    NPT_HttpChunkedOutputStream(NPT_OutputStream& stream);
    ~NPT_HttpChunkedOutputStream() override;

    // NPT_OutputStream methods
    NPT_Result Write(const void* buffer, 
                     NPT_Size    bytes_to_write, 
                     NPT_Size*   bytes_written = NULL) override;
    NPT_Result Seek(NPT_Position /*offset*/) override { return NPT_ERROR_NOT_SUPPORTED;}
    NPT_Result Tell(NPT_Position& offset) override    { return m_Stream.Tell(offset);  }
    NPT_Result Flush() override                       { return m_Stream.Flush();       }

protected:
    // members
    NPT_OutputStream& m_Stream;
};

#endif // _NPT_HTTP_H_