/*
 * Copyright (C) 1996-2024 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.
 */

/* DEBUG: section 57    HTTP Status-line */

#include "squid.h"
#include "base/Packable.h"
#include "debug/Stream.h"
#include "http/one/ResponseParser.h"
#include "http/StatusLine.h"
#include "parser/forward.h"
#include "parser/Tokenizer.h"

#include <algorithm>

void
Http::StatusLine::init()
{
    set(Http::ProtocolVersion(), Http::scNone, nullptr);
}

void
Http::StatusLine::clean()
{
    set(Http::ProtocolVersion(), Http::scInternalServerError, nullptr);
}

/* set values */
void
Http::StatusLine::set(const AnyP::ProtocolVersion &newVersion, const Http::StatusCode newStatus, const char *newReason)
{
    version = newVersion;
    status_ = newStatus;
    /* Note: no xstrdup for 'reason', assumes constant 'reasons' */
    reason_ = newReason;
}

const char *
Http::StatusLine::reason() const
{
    return reason_ ? reason_ : Http::StatusCodeString(status());
}

size_t
Http::StatusLine::packedLength() const
{
    // Keep in sync with packInto(). TODO: Refactor to avoid code duplication.

    auto packedStatus = status();
    auto packedReason = reason();

    if (packedStatus == scNone) {
        packedStatus = scInternalServerError;
        packedReason = StatusCodeString(packedStatus);
    }

    // "ICY %3d %s\r\n"
    if (version.protocol == AnyP::PROTO_ICY) {
        return
            + 3 // ICY
            + 1 // SP
            + 3 // %3d (packedStatus)
            + 1 // SP
            + strlen(packedReason) // %s
            + 2; // CRLF
    }

    // "HTTP/%d.%d %3d %s\r\n"
    return
        + 4 // HTTP
        + 1 // "/"
        + 3 // %d.%d (version.major and version.minor)
        + 1 // SP
        + 3 // %3d (packedStatus)
        + 1 // SP
        + strlen(packedReason) // %s
        + 2; // CRLF
}

void
Http::StatusLine::packInto(Packable * p) const
{
    // Keep in sync with packedLength().

    assert(p);

    auto packedStatus = status();
    auto packedReason = reason();

    if (packedStatus == Http::scNone) {
        static unsigned int reports = 0;
        if (++reports <= 100)
            debugs(57, DBG_IMPORTANT, "ERROR: Squid BUG: the internalized response lacks status-code");
        packedStatus = Http::scInternalServerError;
        packedReason = Http::StatusCodeString(packedStatus); // ignore custom reason_ (if any)
    }

    /* local constants */
    /* AYJ: see bug 2469 - RFC2616 confirms stating 'SP characters' plural! */
    static const char *Http1StatusLineFormat = "HTTP/%d.%d %3d %s\r\n";
    static const char *IcyStatusLineFormat = "ICY %3d %s\r\n";

    /* handle ICY protocol status line specially. Pass on the bad format. */
    if (version.protocol == AnyP::PROTO_ICY) {
        debugs(57, 9, "packing sline " << this << " using " << p << ":");
        debugs(57, 9, "FORMAT=" << IcyStatusLineFormat );
        debugs(57, 9, "ICY " << packedStatus << " " << packedReason);
        p->appendf(IcyStatusLineFormat, packedStatus, packedReason);
        return;
    }

    debugs(57, 9, "packing sline " << this << " using " << p << ":");
    debugs(57, 9, "FORMAT=" << Http1StatusLineFormat );
    debugs(57, 9, "HTTP/" << version.major << "." << version.minor << " " << packedStatus << " " << packedReason);
    p->appendf(Http1StatusLineFormat, version.major, version.minor, packedStatus, packedReason);
}

bool
Http::StatusLine::parse(const String &protoPrefix, const char *start, const char *end)
{
    status_ = Http::scInvalidHeader;    /* Squid header parsing error */

    // XXX: Http::Message::parse() has a similar check but is using
    // casesensitive comparison (which is required by HTTP errata?)

    if (protoPrefix.cmp("ICY", 3) == 0) {
        debugs(57, 3, "Invalid HTTP identifier. Detected ICY protocol instead.");
        version = AnyP::ProtocolVersion(AnyP::PROTO_ICY, 1, 0);
        start += protoPrefix.size();
    } else if (protoPrefix.caseCmp(start, protoPrefix.size()) == 0) {

        start += protoPrefix.size();

        if (!xisdigit(*start))
            return false;

        // XXX: HTTPbis have defined this to be single-digit version numbers. no need to sscanf()
        // XXX: furthermore, only HTTP/1 will be using ASCII format digits

        if (sscanf(start, "%d.%d", &version.major, &version.minor) != 2) {
            debugs(57, 7, "Invalid HTTP identifier.");
            return false;
        }
    } else
        return false;

    if (!(start = strchr(start, ' ')))
        return false;

    ++start; // skip SP between HTTP-version and status-code

    assert(start <= end);
    const auto stdStatusAreaLength = 4; // status-code length plus SP
    const auto unparsedLength = end - start;
    const auto statusAreaLength = std::min<size_t>(stdStatusAreaLength, unparsedLength);

    static SBuf statusBuf;
    statusBuf.assign(start, statusAreaLength);
    Parser::Tokenizer tok(statusBuf);
    try {
        One::ResponseParser::ParseResponseStatus(tok, status_);
    } catch (const Parser::InsufficientInput &) {
        debugs(57, 7, "need more; have " << unparsedLength);
        return false;
    } catch (...) {
        debugs(57, 3, "cannot parse status-code area: " << CurrentException);
        return false;
    }

    // XXX check if the given 'reason' is the default status string, if not save to reason_

    /* we ignore 'reason-phrase' */
    /* Should assert start < end ? */
    return true;            /* success */
}