/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */

#ifndef SQUID_SRC_HTTPREPLY_H
#define SQUID_SRC_HTTPREPLY_H

#include "http/StatusLine.h"
#include "HttpBody.h"
#include "HttpRequest.h"

void httpReplyInitModule(void);

/* Sync changes here with HttpReply.cc */

class HttpHdrContRange;

class HttpHdrSc;

class HttpReply: public Http::Message
{
    MEMPROXY_CLASS(HttpReply);

public:
    typedef RefCount<HttpReply> Pointer;

    HttpReply();
    ~HttpReply() override;

    void reset() override;

    /* Http::Message API */
    bool sanityCheckStartLine(const char *buf, const size_t hdr_len, Http::StatusCode *error) override;

    /** \par public, readable; never update these or their .hdr equivalents directly */
    time_t date;

    time_t last_modified;

    time_t expires;

    String content_type;

    HttpHdrSc *surrogate_control;

    /// \returns parsed Content-Range for a 206 response and nil for others
    const HttpHdrContRange *contentRange() const;

    short int keep_alive;

    /** \par public, writable, but use httpReply* interfaces when possible */
    Http::StatusLine sline;

    HttpBody body;      /**< for small constant memory-resident text bodies only */

    String protoPrefix;         /**< e.g., "HTTP/"  */

    bool do_clean;

public:
    int httpMsgParseError() override;

    bool expectingBody(const HttpRequestMethod&, int64_t&) const override;

    bool inheritProperties(const Http::Message *) override;

    /// \returns nil (if no updates are necessary)
    /// \returns a new reply combining this reply with 304 updates (otherwise)
    Pointer recreateOnNotModified(const HttpReply &reply304) const;

    /** set commonly used info with one call */
    void setHeaders(Http::StatusCode status,
                    const char *reason, const char *ctype, int64_t clen, time_t lmt, time_t expires);

    /** \return a ready to use mem buffer with a packed reply */
    MemBuf *pack() const;

    /// construct and return an HTTP/200 (Connection Established) response
    static HttpReplyPointer MakeConnectionEstablished();

    /** construct a 304 reply and return it */
    HttpReplyPointer make304() const;

    void redirect(Http::StatusCode, const char *);

    int64_t bodySize(const HttpRequestMethod&) const;

    /** Checks whether received body exceeds known maximum size.
     * Requires a prior call to calcMaxBodySize().
     */
    bool receivedBodyTooLarge(HttpRequest&, int64_t receivedBodySize);

    /** Checks whether expected body exceeds known maximum size.
     * Requires a prior call to calcMaxBodySize().
     */
    bool expectedBodyTooLarge(HttpRequest& request);

    int validatorsMatch (HttpReply const *other) const;

    /// adds status line and header to the given Packable
    /// assumes that `p` can quickly process small additions
    void packHeadersUsingFastPacker(Packable &p) const;
    /// same as packHeadersUsingFastPacker() but assumes that `p` cannot quickly process small additions
    void packHeadersUsingSlowPacker(Packable &p) const;

    /** Clone this reply.
     *  Could be done as a copy-contructor but we do not want to accidentally copy a HttpReply..
     */
    HttpReply *clone() const override;

    void hdrCacheInit() override;

    /// whether our Date header value is smaller than theirs
    /// \returns false if any information is missing
    bool olderThan(const HttpReply *them) const;

    /// Some response status codes prohibit sending Content-Length (RFC 7230 section 3.3.2).
    void removeIrrelevantContentLength();

    void configureContentLengthInterpreter(Http::ContentLengthInterpreter &) override;
    /// parses reply header using Parser
    bool parseHeader(Http1::Parser &hp);

    /// Parses response status line and headers at the start of the given
    /// NUL-terminated buffer of the given size. Respects reply_header_max_size.
    /// Assures pstate becomes Http::Message::psParsed on (and only on) success.
    /// \returns the number of bytes in a successfully parsed prefix (or zero)
    /// \retval 0 implies that more data is needed to parse the response prefix
    size_t parseTerminatedPrefix(const char *, size_t);

    /// approximate size of a "status-line CRLF headers CRLF" sequence
    /// \sa HttpRequest::prefixLen()
    size_t prefixLen() const;

private:
    /** initialize */
    void init();

    void clean();

    void hdrCacheClean();

    void packInto(MemBuf &) const;

    /* ez-routines */
    /** \return construct 304 reply and pack it into a MemBuf */
    MemBuf *packed304Reply() const;

    /* header manipulation */
    time_t hdrExpirationTime();

    /** Calculates and stores maximum body size if needed.
     * Used by receivedBodyTooLarge() and expectedBodyTooLarge().
     */
    void calcMaxBodySize(HttpRequest& request) const;

    mutable int64_t bodySizeMax; /**< cached result of calcMaxBodySize */

    HttpHdrContRange *content_range; ///< parsed Content-Range; nil for non-206 responses!

protected:
    void packFirstLineInto(Packable * p, bool) const override { sline.packInto(p); }

    bool parseFirstLine(const char *start, const char *end) override;
};

#endif /* SQUID_SRC_HTTPREPLY_H */