/*
 The MIT License (MIT)
 
 Copyright (c) 2013-2015 SRS(simple-rtmp-server)
 
 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.
 */

#ifndef SRS_PROTOCOL_HTTP_HPP
#define SRS_PROTOCOL_HTTP_HPP

/*
 #include <srs_http_stack.hpp>
 */
#include <srs_core.hpp>

#include <map>
#include <string>
#include <vector>

// for srs-librtmp, @see https://github.com/simple-rtmp-server/srs/issues/213
#ifndef _WIN32
#include <sys/uio.h>
#endif

class SrsFileReader;
class SrsHttpHeader;
class ISrsHttpMessage;
class SrsHttpMuxEntry;
class ISrsHttpResponseWriter;

// http specification
// CR             = <US-ASCII CR, carriage return (13)>
#define SRS_HTTP_CR SRS_CONSTS_CR // 0x0D
// LF             = <US-ASCII LF, linefeed (10)>
#define SRS_HTTP_LF SRS_CONSTS_LF // 0x0A
// SP             = <US-ASCII SP, space (32)>
#define SRS_HTTP_SP ' ' // 0x20
// HT             = <US-ASCII HT, horizontal-tab (9)>
#define SRS_HTTP_HT '\x09' // 0x09

// HTTP/1.1 defines the sequence CR LF as the end-of-line marker for all
// protocol elements except the entity-body (see appendix 19.3 for
// tolerant applications).
#define SRS_HTTP_CRLF "\r\n" // 0x0D0A
#define SRS_HTTP_CRLFCRLF "\r\n\r\n" // 0x0D0A0D0A

// @see ISrsHttpMessage._http_ts_send_buffer
#define SRS_HTTP_TS_SEND_BUFFER_SIZE 4096

// for ead all of http body, read each time.
#define SRS_HTTP_READ_CACHE_BYTES 4096

// default http listen port.
#define SRS_DEFAULT_HTTP_PORT 80

// for http parser macros
#define SRS_CONSTS_HTTP_OPTIONS HTTP_OPTIONS
#define SRS_CONSTS_HTTP_GET HTTP_GET
#define SRS_CONSTS_HTTP_POST HTTP_POST
#define SRS_CONSTS_HTTP_PUT HTTP_PUT
#define SRS_CONSTS_HTTP_DELETE HTTP_DELETE

// helper function: response in json format.
extern int srs_http_response_json(ISrsHttpResponseWriter* w, std::string data);

// get the status text of code.
extern std::string srs_generate_http_status_text(int status);

// bodyAllowedForStatus reports whether a given response status code
// permits a body.  See RFC2616, section 4.4.
extern bool srs_go_http_body_allowd(int status);

// DetectContentType implements the algorithm described
// at http://mimesniff.spec.whatwg.org/ to determine the
// Content-Type of the given data.  It considers at most the
// first 512 bytes of data.  DetectContentType always returns
// a valid MIME type: if it cannot determine a more specific one, it
// returns "application/octet-stream".
extern std::string srs_go_http_detect(char* data, int size);

// state of message
enum SrsHttpParseState {
    SrsHttpParseStateInit = 0,
    SrsHttpParseStateStart,
    SrsHttpParseStateHeaderComplete,
    SrsHttpParseStateMessageComplete
};

// A Header represents the key-value pairs in an HTTP header.
class SrsHttpHeader
{
private:
    std::map<std::string, std::string> headers;
public:
    SrsHttpHeader();
    virtual ~SrsHttpHeader();
public:
    // Add adds the key, value pair to the header.
    // It appends to any existing values associated with key.
    virtual void set(std::string key, std::string value);
    // Get gets the first value associated with the given key.
    // If there are no values associated with the key, Get returns "".
    // To access multiple values of a key, access the map directly
    // with CanonicalHeaderKey.
    virtual std::string get(std::string key);
public:
    /**
     * get the content length. -1 if not set.
     */
    virtual int64_t content_length();
    /**
     * set the content length by header "Content-Length"
     */
    virtual void set_content_length(int64_t size);
public:
    /**
     * get the content type. empty string if not set.
     */
    virtual std::string content_type();
    /**
     * set the content type by header "Content-Type"
     */
    virtual void set_content_type(std::string ct);
public:
    /**
     * write all headers to string stream.
     */
    virtual void write(std::stringstream& ss);
};

// A ResponseWriter interface is used by an HTTP handler to
// construct an HTTP response.
// Usage 1, response with specified length content:
//      ISrsHttpResponseWriter* w; // create or get response.
//      std::string msg = "Hello, HTTP!";
//      w->header()->set_content_type("text/plain; charset=utf-8");
//      w->header()->set_content_length(msg.length());
//      w->write_header(SRS_CONSTS_HTTP_OK);
//      w->write((char*)msg.data(), (int)msg.length());
//      w->final_request(); // optional flush.
// Usage 2, response with HTTP code only, zero content length.
//      ISrsHttpResponseWriter* w; // create or get response.
//      w->header()->set_content_length(0);
//      w->write_header(SRS_CONSTS_HTTP_OK);
//      w->final_request();
// Usage 3, response in chunked encoding.
//      ISrsHttpResponseWriter* w; // create or get response.
//      std::string msg = "Hello, HTTP!";
//      w->header()->set_content_type("application/octet-stream");
//      w->write_header(SRS_CONSTS_HTTP_OK);
//      w->write((char*)msg.data(), (int)msg.length());
//      w->write((char*)msg.data(), (int)msg.length());
//      w->write((char*)msg.data(), (int)msg.length());
//      w->write((char*)msg.data(), (int)msg.length());
//      w->final_request(); // required to end the chunked and flush.
class ISrsHttpResponseWriter
{
public:
    ISrsHttpResponseWriter();
    virtual ~ISrsHttpResponseWriter();
public:
    // when chunked mode,
    // final the request to complete the chunked encoding.
    // for no-chunked mode,
    // final to send request, for example, content-length is 0.
    virtual int final_request() = 0;
    
    // Header returns the header map that will be sent by WriteHeader.
    // Changing the header after a call to WriteHeader (or Write) has
    // no effect.
    virtual SrsHttpHeader* header() = 0;
    
    // Write writes the data to the connection as part of an HTTP reply.
    // If WriteHeader has not yet been called, Write calls WriteHeader(http.StatusOK)
    // before writing the data.  If the Header does not contain a
    // Content-Type line, Write adds a Content-Type set to the result of passing
    // the initial 512 bytes of written data to DetectContentType.
    // @param data, the data to send. NULL to flush header only.
    virtual int write(char* data, int size) = 0;
    /**
     * for the HTTP FLV, to writev to improve performance.
     * @see https://github.com/simple-rtmp-server/srs/issues/405
     */
    virtual int writev(iovec* iov, int iovcnt, ssize_t* pnwrite) = 0;
    
    // WriteHeader sends an HTTP response header with status code.
    // If WriteHeader is not called explicitly, the first call to Write
    // will trigger an implicit WriteHeader(http.StatusOK).
    // Thus explicit calls to WriteHeader are mainly used to
    // send error codes.
    // @remark, user must set header then write or write_header.
    virtual void write_header(int code) = 0;
};

/**
 * the reader interface for http response.
 */
class ISrsHttpResponseReader
{
public:
    ISrsHttpResponseReader();
    virtual ~ISrsHttpResponseReader();
public:
    /**
     * whether response read EOF.
     */
    virtual bool eof() = 0;
    /**
     * read from the response body.
     * @param data, the buffer to read data buffer to.
     * @param nb_data, the max size of data buffer.
     * @param nb_read, the actual read size of bytes. NULL to ignore.
     * @remark when eof(), return error.
     */
    virtual int read(char* data, int nb_data, int* nb_read) = 0;
};

// Objects implementing the Handler interface can be
// registered to serve a particular path or subtree
// in the HTTP server.
//
// ServeHTTP should write reply headers and data to the ResponseWriter
// and then return.  Returning signals that the request is finished
// and that the HTTP server can move on to the next request on
// the connection.
class ISrsHttpHandler
{
public:
    SrsHttpMuxEntry* entry;
public:
    ISrsHttpHandler();
    virtual ~ISrsHttpHandler();
public:
    virtual int serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r) = 0;
};

// Redirect to a fixed URL
class SrsHttpRedirectHandler : public ISrsHttpHandler
{
private:
    std::string url;
    int code;
public:
    SrsHttpRedirectHandler(std::string u, int c);
    virtual ~SrsHttpRedirectHandler();
public:
    virtual int serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r);
};

// NotFound replies to the request with an HTTP 404 not found error.
class SrsHttpNotFoundHandler : public ISrsHttpHandler
{
public:
    SrsHttpNotFoundHandler();
    virtual ~SrsHttpNotFoundHandler();
public:
    virtual int serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r);
};

// FileServer returns a handler that serves HTTP requests
// with the contents of the file system rooted at root.
//
// To use the operating system's file system implementation,
// use http.Dir:
//
//     http.Handle("/", SrsHttpFileServer("/tmp"))
//     http.Handle("/", SrsHttpFileServer("static-dir"))
class SrsHttpFileServer : public ISrsHttpHandler
{
protected:
    std::string dir;
public:
    SrsHttpFileServer(std::string root_dir);
    virtual ~SrsHttpFileServer();
public:
    virtual int serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r);
private:
    /**
     * serve the file by specified path
     */
    virtual int serve_file(ISrsHttpResponseWriter* w, ISrsHttpMessage* r, std::string fullpath);
    virtual int serve_flv_file(ISrsHttpResponseWriter* w, ISrsHttpMessage* r, std::string fullpath);
    virtual int serve_mp4_file(ISrsHttpResponseWriter* w, ISrsHttpMessage* r, std::string fullpath);
protected:
    /**
     * when access flv file with x.flv?start=xxx
     */
    virtual int serve_flv_stream(ISrsHttpResponseWriter* w, ISrsHttpMessage* r, std::string fullpath, int offset);
    /**
     * when access mp4 file with x.mp4?range=start-end
     * @param start the start offset in bytes.
     * @param end the end offset in bytes. -1 to end of file.
     * @remark response data in [start, end].
     */
    virtual int serve_mp4_stream(ISrsHttpResponseWriter* w, ISrsHttpMessage* r, std::string fullpath, int start, int end);
protected:
    /**
     * copy the fs to response writer in size bytes.
     */
    virtual int copy(ISrsHttpResponseWriter* w, SrsFileReader* fs, ISrsHttpMessage* r, int size);
};

// the mux entry for server mux.
// the matcher info, for example, the pattern and handler.
class SrsHttpMuxEntry
{
public:
    bool explicit_match;
    ISrsHttpHandler* handler;
    std::string pattern;
    bool enabled;
public:
    SrsHttpMuxEntry();
    virtual ~SrsHttpMuxEntry();
};

/**
 * the hijacker for http pattern match.
 */
class ISrsHttpMatchHijacker
{
public:
    ISrsHttpMatchHijacker();
    virtual ~ISrsHttpMatchHijacker();
public:
    /**
     * when match the request failed, no handler to process request.
     * @param request the http request message to match the handler.
     * @param ph the already matched handler, hijack can rewrite it.
     */
    virtual int hijack(ISrsHttpMessage* request, ISrsHttpHandler** ph) = 0;
};

// ServeMux is an HTTP request multiplexer.
// It matches the URL of each incoming request against a list of registered
// patterns and calls the handler for the pattern that
// most closely matches the URL.
//
// Patterns name fixed, rooted paths, like "/favicon.ico",
// or rooted subtrees, like "/images/" (note the trailing slash).
// Longer patterns take precedence over shorter ones, so that
// if there are handlers registered for both "/images/"
// and "/images/thumbnails/", the latter handler will be
// called for paths beginning "/images/thumbnails/" and the
// former will receive requests for any other paths in the
// "/images/" subtree.
//
// Note that since a pattern ending in a slash names a rooted subtree,
// the pattern "/" matches all paths not matched by other registered
// patterns, not just the URL with Path == "/".
//
// Patterns may optionally begin with a host name, restricting matches to
// URLs on that host only.  Host-specific patterns take precedence over
// general patterns, so that a handler might register for the two patterns
// "/codesearch" and "codesearch.google.com/" without also taking over
// requests for "http://www.google.com/".
//
// ServeMux also takes care of sanitizing the URL request path,
// redirecting any request containing . or .. elements to an
// equivalent .- and ..-free URL.
class SrsHttpServeMux
{
private:
    // the pattern handler, to handle the http request.
    std::map<std::string, SrsHttpMuxEntry*> entries;
    // the vhost handler.
    // when find the handler to process the request,
    // append the matched vhost when pattern not starts with /,
    // for example, for pattern /live/livestream.flv of vhost ossrs.net,
    // the path will rewrite to ossrs.net/live/livestream.flv
    std::map<std::string, ISrsHttpHandler*> vhosts;
    // all hijackers for http match.
    // for example, the hstrs(http stream trigger rtmp source)
    // can hijack and install handler when request incoming and no handler.
    std::vector<ISrsHttpMatchHijacker*> hijackers;
public:
    SrsHttpServeMux();
    virtual ~SrsHttpServeMux();
public:
    /**
     * initialize the http serve mux.
     */
    virtual int initialize();
    /**
     * hijack the http match.
     */
    virtual void hijack(ISrsHttpMatchHijacker* h);
    virtual void unhijack(ISrsHttpMatchHijacker* h);
public:
    // Handle registers the handler for the given pattern.
    // If a handler already exists for pattern, Handle panics.
    virtual int handle(std::string pattern, ISrsHttpHandler* handler);
    // interface ISrsHttpHandler
public:
    virtual int serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r);
private:
    virtual int find_handler(ISrsHttpMessage* r, ISrsHttpHandler** ph);
    virtual int match(ISrsHttpMessage* r, ISrsHttpHandler** ph);
    virtual bool path_match(std::string pattern, std::string path);
};

// for http header.
typedef std::pair<std::string, std::string> SrsHttpHeaderField;

// A Request represents an HTTP request received by a server
// or to be sent by a client.
//
// The field semantics differ slightly between client and server
// usage. In addition to the notes on the fields below, see the
// documentation for Request.Write and RoundTripper.
/**
 * the http message, request or response.
 */
class ISrsHttpMessage
{
private:
    /**
     * use a buffer to read and send ts file.
     */
    // TODO: FIXME: remove it.
    char* _http_ts_send_buffer;
public:
    ISrsHttpMessage();
    virtual ~ISrsHttpMessage();
public:
    /**
     * the http request level cache.
     */
    virtual char* http_ts_send_buffer();
public:
    virtual u_int8_t method() = 0;
    virtual u_int16_t status_code() = 0;
    /**
     * method helpers.
     */
    virtual std::string method_str() = 0;
    virtual bool is_http_get() = 0;
    virtual bool is_http_put() = 0;
    virtual bool is_http_post() = 0;
    virtual bool is_http_delete() = 0;
    virtual bool is_http_options() = 0;
public:
    /**
     * whether should keep the connection alive.
     */
    virtual bool is_keep_alive() = 0;
    /**
     * the uri contains the host and path.
     */
    virtual std::string uri() = 0;
    /**
     * the url maybe the path.
     */
    virtual std::string url() = 0;
    virtual std::string host() = 0;
    virtual std::string path() = 0;
    virtual std::string ext() = 0;
public:
    /**
     * read body to string.
     * @remark for small http body.
     */
    virtual int body_read_all(std::string& body) = 0;
    /**
     * get the body reader, to read one by one.
     * @remark when body is very large, or chunked, use this.
     */
    virtual ISrsHttpResponseReader* body_reader() = 0;
    /**
     * the content length, -1 for chunked or not set.
     */
    virtual int64_t content_length() = 0;
public:
    /**
     * get the param in query string,
     * for instance, query is "start=100&end=200",
     * then query_get("start") is "100", and query_get("end") is "200"
     */
    virtual std::string query_get(std::string key) = 0;
    /**
     * get the headers.
     */
    virtual int request_header_count() = 0;
    virtual std::string request_header_key_at(int index) = 0;
    virtual std::string request_header_value_at(int index) = 0;
};

#endif
