// Copyright (c) 2022 Robin E. R. Davies
//
// 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.

#include "HtmlHelper.hpp"
#include <sstream>
#include <string>
#include <cstring>
#include "ss.hpp"
#include <map>

using namespace pipedal;

// non-localizable. RFC 7231 Date Format
;
static const char *INVARIANT_WEEK_DAYS[] =
    {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
// non-localizable. RFC 7231 Date Format
static const char *INVARIANT_MONTHS[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
// non-localizable. RFC 7231 Date Format
static const char *FORMAT = "%s, %02d %s %04d %02d:%02d:%02d GMT";

std::string HtmlHelper::timeToHttpDate()
{
    return timeToHttpDate(time(nullptr));
}

std::string HtmlHelper::timeToHttpDate(std::filesystem::file_time_type time)
{

    // Convert to time_t.
    auto sctp = std::chrono::time_point_cast<std::chrono::system_clock::duration>(time - std::filesystem::file_time_type::clock::now() + std::chrono::system_clock::now());

    auto time_t_value = std::chrono::system_clock::to_time_t(sctp);
    return timeToHttpDate(time_t_value);
}

std::string HtmlHelper::timeToHttpDate(time_t time)
{
    // RFC 7231, IMF-fixdate.

    struct tm gmTm;

    if (gmtime_r(&time, &gmTm) == nullptr)
    {
        return "Mon, 01 Jan 1970 00:00:00 GMT";
    }
    char szBuffer[sizeof("Mon, 01 Jan 1970 00:00:00 GMT+")];
    snprintf(szBuffer, sizeof(szBuffer), FORMAT,
             INVARIANT_WEEK_DAYS[gmTm.tm_wday],
             gmTm.tm_mday,
             INVARIANT_MONTHS[gmTm.tm_mon],
             gmTm.tm_year + 1900,
             gmTm.tm_hour,
             gmTm.tm_min,
             gmTm.tm_sec);
    return szBuffer;
}

static int hexN(char c)
{
    if (c >= '0' && c <= '9')
        return c - '0';
    if (c >= 'a' && c <= 'f')
        return 10 + c - 'a';
    if (c >= 'A' && c <= 'F')
        return 10 + c - 'A';
    throw std::invalid_argument("Malformed URL.");
}
static char hexChar(char c1, char c2)
{
    return (char)((hexN(c1) << 4) + hexN(c2));
}

class SafeCharacterMap
{
    bool safeCharacter[256];

public:
    SafeCharacterMap()
    {
        for (int i = 0; i < 0x20; ++i)
        {
            safeCharacter[i] = false;
        }
        for (int i = 0x20; i < 0x80; ++i)
        {
            safeCharacter[i] = true;
        }
        for (int i = 0x80; i < 256; ++i)
        {
            safeCharacter[i] = false;
        }
        const char *unsafeCharacters = ":/+?=#%@ ";
        for (const char *p = unsafeCharacters; *p != 0; ++p)
        {
            safeCharacter[(uint8_t)*p] = false;
        }
    }

    bool isSafeCharacter(char c) { return safeCharacter[(uint8_t)c]; }
} g_safeCharacterMap;

std::string HtmlHelper::encode_url_segment(const char *pStart, const char *pEnd, bool isQuerySegment)
{
    std::stringstream s;
    encode_url_segment(s, pStart, pEnd, isQuerySegment);
    return s.str();
}

static char hexChars[] = "0123456789ABCDEF";

void HtmlHelper::encode_url_segment(std::ostream &os, const char *pStart, const char *pEnd, bool isQuerySegment)
{
    while (pStart != pEnd)
    {
        char c = *pStart++;
        if (g_safeCharacterMap.isSafeCharacter(c))
        {
            os << c;
        }
        else if (c == ' ' && isQuerySegment)
        {
            os << '+';

            os << c;
        }
        else
        {
            os << '%' << hexChars[(c >> 4) & 0x0f] << hexChars[c & 0x0F];
        }
    }
}

std::string HtmlHelper::decode_url_segment(const char *pStart, const char *pEnd, bool isQuery)
{
    std::stringstream s;
    auto p = pStart;
    while (p != pEnd)
    {
        char c = *p;
        ++p;
        if (c == '+')
        {
            s << ' ';
        }
        else if (c != '%')
        {
            s << c;
        }
        else
        {
            if (pStart + 2 < pEnd)
            {
                char c1 = *p;
                ++p;
                char c2 = *p;
                ++p;
                s << hexChar(c1, c2);
            }
            else
            {
                throw std::invalid_argument("Malformed URL.");
            }
        }
    }
    return s.str();
}

std::string HtmlHelper::decode_url_segment(const char *text, bool isQuery)
{
    return decode_url_segment(text, text + strlen(text), isQuery);
}

void HtmlHelper::utf32_to_utf8_stream(std::ostream &s, uint32_t uc)
{
    if (uc < 0x80u)
    {
        s << (char)uc;
    }
    else if (uc < 0x800u)
    {
        s << (char)(0xC0 + (uc >> 6));
        s << (char)(0x80 + (uc & 0x3F));
    }
    else if (uc < 0x10000u)
    {
        s << (char)(0xE0 + (uc >> 12));
        s << (char)(0x80 + ((uc >> 6) & 0x3F));
        s << (char)(0x80 + (uc & 0x3F));
    }
    else if (uc < 0x0110000)
    {
        s << (char)(0xF0 + (uc >> 18));
        s << (char)(0x80 + ((uc >> 12) & 0x3F));
        s << (char)(0x80 + ((uc >> 6) & 0x3F));
        s << (char)(0x80 + (uc & 0x3F));
    }
    else
    {
        throw std::range_error("Illegal UTF-32 character.");
    }
}

const std::string ESPECIALS = "()<>@,;:\"/[]?.=";

#define MAX_FILENAME_LENGTH 96
#define MAX_SEGMENT_LENGTH 74 // 75 per RFC2047.2. But leave space for a ';' to allow easier breaking of lines.

std::string HtmlHelper::Rfc5987EncodeFileName(const std::string &name)
{
    // Encode all characters. Let the browser handle safe-ifying the actual name, since that's os dependent.
    std::stringstream s;
    std::string prefix = "UTF-8''";
    std::string postfix = "";
    s << prefix;
    for (char c : name)
    {
        uint8_t uc = (uint8_t)c;
        if (uc < 0x20 || uc >= 0x80 || ESPECIALS.find(c) != std::string::npos)
        {
            s << '%' << hexChars[uc >> 4] << hexChars[uc & 0x0F];
        }
        else
        {
            s << c;
        }
    }
    s << postfix;
    return s.str();
}

#define MAX_FILE_NAME_LENGHT 96

const std::string SF_SPECIALS = "<>@;:\"\'/[]?=";
const std::string ISF_SPECIALS = "\\:";


bool HtmlHelper::IsSafeFileName(const std::filesystem::path &path)
{
    for (const auto&segment: path)
    {
        if (segment.string() == "..")
        {
            return false;
        }
        for (char c: segment.string())
        {
            unsigned char uc = (unsigned char)c;
            if (uc < 0x20 || uc >= 0x80 || ISF_SPECIALS.find(c) != std::string::npos)
            {
                return false;
            }

        }
    }
    return true;
}
std::string HtmlHelper::SafeFileName(const std::string &name)
{
    std::stringstream s;
    for (char c : name)
    {
        uint8_t uc = (uint8_t)c;
        if (uc < 0x20 || uc >= 0x80 || SF_SPECIALS.find(c) != std::string::npos)
        {
            s << '_';
        }
        else
        {
            s << c;
        }
    }
    return s.str();
}

std::string HtmlHelper::HtmlEncode(const std::string &text)
{
    std::stringstream os;
    for (char c : text)
    {
        switch (c)
        {
        case '<':
            os << "&lt;";
            break;
        case '>':
            os << "&gt;";
            break;
        case '&':
            os << "&amp;";
            break;
        default:
            os << c;
            break;
        }
    }
    return os.str();
}

static const uint64_t crc64_table[256] = {
    0x0000000000000000ULL, 0x42F0E1EBA9EA3693ULL, 0x85E1C3D753D46D26ULL, 0xC711223CFA3E5BB5ULL,
    0x493366450E42ECDFULL, 0x0BC387AEA7A8DA4CULL, 0xCCD2A5925D9681F9ULL, 0x8E224479F47CB76AULL,
    0x9266CC8A1C85D9BEULL, 0xD0962D61B56FEF2DULL, 0x17870F5D4F51B498ULL, 0x5577EEB6E6BB820BULL,
    0xDB55AACF12C73561ULL, 0x99A54B24BB2D03F2ULL, 0x5EB4691841135847ULL, 0x1C4488F3E8F96ED4ULL,
    0x663D78FF90E185EFULL, 0x24CD9914390BB37CULL, 0xE3DCBB28C335E8C9ULL, 0xA12C5AC36ADFDE5AULL,
    0x2F0E1EBA9EA36930ULL, 0x6DFEFF5137495FA3ULL, 0xAAEFDD6DCD770416ULL, 0xE81F3C86649D3285ULL,
    0xF45BB4758C645C51ULL, 0xB6AB559E258E6AC2ULL, 0x71BA77A2DFB03177ULL, 0x334A9649765A07E4ULL,
    0xBD68D2308226B08EULL, 0xFF9833DB2BCC861DULL, 0x388911E7D1F2DDA8ULL, 0x7A79F00C7818EB3BULL,
    0xCC7AF1FF21C30BDEULL, 0x8E8A101488293D4DULL, 0x499B3228721766F8ULL, 0x0B6BD3C3DBFD506BULL,
    0x854997BA2F81E701ULL, 0xC7B97651866BD192ULL, 0x00A8546D7C558A27ULL, 0x4258B586D5BFBCB4ULL,
    0x5E1C3D753D46D260ULL, 0x1CECDC9E94ACE4F3ULL, 0xDBFDFEA26E92BF46ULL, 0x990D1F49C77889D5ULL,
    0x172F5B3033043EBFULL, 0x55DFBADB9AEE082CULL, 0x92CE98E760D05399ULL, 0xD03E790CC93A650AULL,
    0xAA478900B1228E31ULL, 0xE8B768EB18C8B8A2ULL, 0x2FA64AD7E2F6E317ULL, 0x6D56AB3C4B1CD584ULL,
    0xE374EF45BF6062EEULL, 0xA1840EAE168A547DULL, 0x66952C92ECB40FC8ULL, 0x2465CD79455E395BULL,
    0x3821458AADA7578FULL, 0x7AD1A461044D611CULL, 0xBDC0865DFE733AA9ULL, 0xFF3067B657990C3AULL,
    0x711223CFA3E5BB50ULL, 0x33E2C2240A0F8DC3ULL, 0xF4F3E018F031D676ULL, 0xB60301F359DBE0E5ULL,
    0xDA050215EA6C212FULL, 0x98F5E3FE438617BCULL, 0x5FE4C1C2B9B84C09ULL, 0x1D14202910527A9AULL,
    0x93366450E42ECDF0ULL, 0xD1C685BB4DC4FB63ULL, 0x16D7A787B7FAA0D6ULL, 0x5427466C1E109645ULL,
    0x4863CE9FF6E9F891ULL, 0x0A932F745F03CE02ULL, 0xCD820D48A53D95B7ULL, 0x8F72ECA30CD7A324ULL,
    0x0150A8DAF8AB144EULL, 0x43A04931514122DDULL, 0x84B16B0DAB7F7968ULL, 0xC6418AE602954FFBULL,
    0xBC387AEA7A8DA4C0ULL, 0xFEC89B01D3679253ULL, 0x39D9B93D2959C9E6ULL, 0x7B2958D680B3FF75ULL,
    0xF50B1CAF74CF481FULL, 0xB7FBFD44DD257E8CULL, 0x70EADF78271B2539ULL, 0x321A3E938EF113AAULL,
    0x2E5EB66066087D7EULL, 0x6CAE578BCFE24BEDULL, 0xABBF75B735DC1058ULL, 0xE94F945C9C3626CBULL,
    0x676DD025684A91A1ULL, 0x259D31CEC1A0A732ULL, 0xE28C13F23B9EFC87ULL, 0xA07CF2199274CA14ULL,
    0x167FF3EACBAF2AF1ULL, 0x548F120162451C62ULL, 0x939E303D987B47D7ULL, 0xD16ED1D631917144ULL,
    0x5F4C95AFC5EDC62EULL, 0x1DBC74446C07F0BDULL, 0xDAAD56789639AB08ULL, 0x985DB7933FD39D9BULL,
    0x84193F60D72AF34FULL, 0xC6E9DE8B7EC0C5DCULL, 0x01F8FCB784FE9E69ULL, 0x43081D5C2D14A8FAULL,
    0xCD2A5925D9681F90ULL, 0x8FDAB8CE70822903ULL, 0x48CB9AF28ABC72B6ULL, 0x0A3B7B1923564425ULL,
    0x70428B155B4EAF1EULL, 0x32B26AFEF2A4998DULL, 0xF5A348C2089AC238ULL, 0xB753A929A170F4ABULL,
    0x3971ED50550C43C1ULL, 0x7B810CBBFCE67552ULL, 0xBC902E8706D82EE7ULL, 0xFE60CF6CAF321874ULL,
    0xE224479F47CB76A0ULL, 0xA0D4A674EE214033ULL, 0x67C58448141F1B86ULL, 0x253565A3BDF52D15ULL,
    0xAB1721DA49899A7FULL, 0xE9E7C031E063ACECULL, 0x2EF6E20D1A5DF759ULL, 0x6C0603E6B3B7C1CAULL,
    0xF6FAE5C07D3274CDULL, 0xB40A042BD4D8425EULL, 0x731B26172EE619EBULL, 0x31EBC7FC870C2F78ULL,
    0xBFC9838573709812ULL, 0xFD39626EDA9AAE81ULL, 0x3A28405220A4F534ULL, 0x78D8A1B9894EC3A7ULL,
    0x649C294A61B7AD73ULL, 0x266CC8A1C85D9BE0ULL, 0xE17DEA9D3263C055ULL, 0xA38D0B769B89F6C6ULL,
    0x2DAF4F0F6FF541ACULL, 0x6F5FAEE4C61F773FULL, 0xA84E8CD83C212C8AULL, 0xEABE6D3395CB1A19ULL,
    0x90C79D3FEDD3F122ULL, 0xD2377CD44439C7B1ULL, 0x15265EE8BE079C04ULL, 0x57D6BF0317EDAA97ULL,
    0xD9F4FB7AE3911DFDULL, 0x9B041A914A7B2B6EULL, 0x5C1538ADB04570DBULL, 0x1EE5D94619AF4648ULL,
    0x02A151B5F156289CULL, 0x4051B05E58BC1E0FULL, 0x87409262A28245BAULL, 0xC5B073890B687329ULL,
    0x4B9237F0FF14C443ULL, 0x0962D61B56FEF2D0ULL, 0xCE73F427ACC0A965ULL, 0x8C8315CC052A9FF6ULL,
    0x3A80143F5CF17F13ULL, 0x7870F5D4F51B4980ULL, 0xBF61D7E80F251235ULL, 0xFD913603A6CF24A6ULL,
    0x73B3727A52B393CCULL, 0x31439391FB59A55FULL, 0xF652B1AD0167FEEAULL, 0xB4A25046A88DC879ULL,
    0xA8E6D8B54074A6ADULL, 0xEA16395EE99E903EULL, 0x2D071B6213A0CB8BULL, 0x6FF7FA89BA4AFD18ULL,
    0xE1D5BEF04E364A72ULL, 0xA3255F1BE7DC7CE1ULL, 0x64347D271DE22754ULL, 0x26C49CCCB40811C7ULL,
    0x5CBD6CC0CC10FAFCULL, 0x1E4D8D2B65FACC6FULL, 0xD95CAF179FC497DAULL, 0x9BAC4EFC362EA149ULL,
    0x158E0A85C2521623ULL, 0x577EEB6E6BB820B0ULL, 0x906FC95291867B05ULL, 0xD29F28B9386C4D96ULL,
    0xCEDBA04AD0952342ULL, 0x8C2B41A1797F15D1ULL, 0x4B3A639D83414E64ULL, 0x09CA82762AAB78F7ULL,
    0x87E8C60FDED7CF9DULL, 0xC51827E4773DF90EULL, 0x020905D88D03A2BBULL, 0x40F9E43324E99428ULL,
    0x2CFFE7D5975E55E2ULL, 0x6E0F063E3EB46371ULL, 0xA91E2402C48A38C4ULL, 0xEBEEC5E96D600E57ULL,
    0x65CC8190991CB93DULL, 0x273C607B30F68FAEULL, 0xE02D4247CAC8D41BULL, 0xA2DDA3AC6322E288ULL,
    0xBE992B5F8BDB8C5CULL, 0xFC69CAB42231BACFULL, 0x3B78E888D80FE17AULL, 0x7988096371E5D7E9ULL,
    0xF7AA4D1A85996083ULL, 0xB55AACF12C735610ULL, 0x724B8ECDD64D0DA5ULL, 0x30BB6F267FA73B36ULL,
    0x4AC29F2A07BFD00DULL, 0x08327EC1AE55E69EULL, 0xCF235CFD546BBD2BULL, 0x8DD3BD16FD818BB8ULL,
    0x03F1F96F09FD3CD2ULL, 0x41011884A0170A41ULL, 0x86103AB85A2951F4ULL, 0xC4E0DB53F3C36767ULL,
    0xD8A453A01B3A09B3ULL, 0x9A54B24BB2D03F20ULL, 0x5D45907748EE6495ULL, 0x1FB5719CE1045206ULL,
    0x919735E51578E56CULL, 0xD367D40EBC92D3FFULL, 0x1476F63246AC884AULL, 0x568617D9EF46BED9ULL,
    0xE085162AB69D5E3CULL, 0xA275F7C11F7768AFULL, 0x6564D5FDE549331AULL, 0x279434164CA30589ULL,
    0xA9B6706FB8DFB2E3ULL, 0xEB46918411358470ULL, 0x2C57B3B8EB0BDFC5ULL, 0x6EA7525342E1E956ULL,
    0x72E3DAA0AA188782ULL, 0x30133B4B03F2B111ULL, 0xF7021977F9CCEAA4ULL, 0xB5F2F89C5026DC37ULL,
    0x3BD0BCE5A45A6B5DULL, 0x79205D0E0DB05DCEULL, 0xBE317F32F78E067BULL, 0xFCC19ED95E6430E8ULL,
    0x86B86ED5267CDBD3ULL, 0xC4488F3E8F96ED40ULL, 0x0359AD0275A8B6F5ULL, 0x41A94CE9DC428066ULL,
    0xCF8B0890283E370CULL, 0x8D7BE97B81D4019FULL, 0x4A6ACB477BEA5A2AULL, 0x089A2AACD2006CB9ULL,
    0x14DEA25F3AF9026DULL, 0x562E43B4931334FEULL, 0x913F6188692D6F4BULL, 0xD3CF8063C0C759D8ULL,
    0x5DEDC41A34BBEEB2ULL, 0x1F1D25F19D51D821ULL, 0xD80C07CD676F8394ULL, 0x9AFCE626CE85B507ULL};

uint64_t HtmlHelper::crc64(uint8_t *data, size_t length, uint64_t crc)
{

    crc = crc ^ uint64_t(-1);
    for (size_t i = 0; i < length; ++i)
    {
        uint8_t c = data[i];
        crc = crc64_table[(crc ^ (uint8_t)c) & 0xFF] ^ (crc >> 8);
    }
    return crc ^ uint64_t(-1);
}


uint64_t HtmlHelper::crc64(const std::string&value, uint64_t crc)
{
    crc = crc ^ uint64_t(-1);
    for (auto c: value)
    {
        crc = crc64_table[(crc ^ (uint8_t)c) & 0xFF] ^ (crc >> 8);
    }
    return crc ^ uint64_t(-1);

}


std::string HtmlHelper::generateEtag(const std::filesystem::path &path)
{
    uint64_t crc = 0;
    crc = crc64(path.string());
    auto fTime = std::filesystem::last_write_time(path);
    crc = crc64((uint8_t*)&fTime, sizeof(fTime));
    return std::to_string(crc);
}

static std::map<int,std::string> httpErrorStrings = 
{
    {200,"OK"},
    {201, "Created"},
    {202, "Accepted"},
    {203, "Non-Authoritative Information"},
    {204, "No Content"},
    {205, "Reset Content"},
    {206, "Partial Content"},
    {300, "Multiple Choices"},
    {301, "Moved Permanently"},
    {302, "Found"},
    {303, "See Other"},
    {304, "Not Modified"},
    {305, "Use Proxy"},
    {307, "Temporary Redirect"},
    {308, "Permanent Redirect"},
    {400, "Bad Request"},
    {401, "Unauthorized"},
    {402, "Payment Required"},
    {403, "Forbidden"},
    {404, "Not Found"},
    {405, "Method Not Allowed"},
    {406, "Not Acceptable"},
    {407, "Proxy Authentication Required"},
    {408, "Request Timeout"},
    {409, "Conflict"},
    {410, "Gone"},
    {411, "Length Required"},
    {412, "Precondition Failed"},
    {413, "Payload Too Large"},
    {414, "URI Too Long"},
    {415, "Unsupported Media Type"},
    {416, "Range Not Satisfiable"},
    {417, "Expectation Failed"},
    {418, "I'm a teapot"},
    {421, "Misdirected Request"},
    {422, "Unprocessable Content"},
    {423, "Locked"},
    {424, "Failed Dependency"},
    {426, "Upgrade Required"},
    {428, "Precondition Required"},
    {429, "Too Many Requests"},
    {431, "Request Header Fields Too Large"},
    {451, "Unavailable For Legal Reasons"},
    {500, "Internal Server Error"},
    {501, "Not Implemented"},
    {502, "Bad Gateway"},
    {503, "Service Unavailable"},
    {504, "Gateway Timeout"},
    {505, "HTTP Version Not Supported"},
    {506, "Variant Also Negotiates"},
    {507, "Insufficient Storage"},
    {508, "Loop Detected"},
    {510, "Not Extended"},
    {511, "Network Authentication Required"}
    

};

std::string HtmlHelper::httpErrorString(int errorCode)
{
    auto ff = httpErrorStrings.find(errorCode);
    if (ff != httpErrorStrings.end())
    {
        return SS(errorCode << ": " << ff->second);
    }
    return SS(errorCode << ": Unknown error");

}

std::string HtmlFormBuilder::build()
{
    std::ostringstream ss;
    bool firstTime = true;
    for (const auto &entry: entries_)
    {
        if (!firstTime) 
        {
            ss << "&";
        }
        ss << entry.key();
        if (entry.value().has_value()) 
        {

            ss << "=" << HtmlHelper::encode_url_segment(entry.value().value(),true);
        }
        firstTime = false;

    }
    return ss.str();
}