/**
 * Copyright (c) 2014, Timothy Stack
 *
 * 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 Timothy Stack 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 THE REGENTS AND CONTRIBUTORS ''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 THE REGENTS OR CONTRIBUTORS 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.
 *
 * @file ptimec_rt.cc
 */

#include "ptimec.hh"

#include <string.h>

#include "base/short_alloc.h"
#include "config.h"

bool
ptime_b_slow(struct exttm* dst, const char* str, off_t& off_inout, ssize_t len)
{
    size_t zone_len = len - off_inout;
    stack_buf allocator;
    auto* zone = allocator.allocate(zone_len + 2);
    const char* end_of_date;

    memcpy(zone, &str[off_inout], zone_len);
    zone[zone_len] = '\0';
    if ((end_of_date = strptime(zone, "%b", &dst->et_tm)) != nullptr) {
        off_inout += end_of_date - zone;
        // Some formats append a dot, maybe to align a 3 letter abbrev with the
        // four letter ones?
        if (off_inout + 1 < len && zone[off_inout] == '.') {
            off_inout += 1;
        }
        dst->et_flags |= ETF_MONTH_SET;
        return true;
    }

    // Some locales (e.g., es_ES on macOS) use abbreviated months with a
    // trailing dot ("ene.", "feb."). If the input lacks the dot, insert one
    // after the alphabetic prefix and retry.
    {
        off_t alpha_len = 0;
        while (alpha_len < (off_t) zone_len && isalpha(zone[alpha_len])) {
            alpha_len++;
        }
        if (alpha_len > 0 && (alpha_len >= (off_t) zone_len
                              || zone[alpha_len] != '.'))
        {
            memmove(zone + alpha_len + 1, zone + alpha_len,
                    zone_len - alpha_len + 1);
            zone[alpha_len] = '.';
            if ((end_of_date = strptime(zone, "%b", &dst->et_tm)) != nullptr) {
                auto consumed = end_of_date - zone;
                // Subtract the inserted dot from consumed length if strptime
                // consumed past it
                if (consumed > alpha_len) {
                    off_inout += consumed - 1;
                } else {
                    off_inout += consumed;
                }
                dst->et_flags |= ETF_MONTH_SET;
                return true;
            }
        }
    }

    return false;
}

bool
ptime_Z_to_gmtoff(exttm* dst, const char* str, off_t& off_inout, ssize_t len)
{
    auto avail = len - off_inout;

    if (avail < 3) {
        return false;
    }

    auto zone_start = (unsigned char*) &str[off_inout];
    uint32_t zone_int = ABR_TO_INT4(zone_start[0] & ~0x20UL,
                                    zone_start[1] & ~0x20UL,
                                    zone_start[2] & ~0x20UL,
                                    avail >= 4 ? zone_start[3] & ~0x20UL : 0);
    switch (zone_int) {
        case ABR_TO_INT('U', 'T', 'C'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET | ETF_Z_IS_UTC; });
            dst->et_gmtoff = 0;
            break;
        case ABR_TO_INT('G', 'M', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET | ETF_Z_IS_GMT; });
            dst->et_gmtoff = 0;
            break;
        case ABR_TO_INT('E', 'A', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = 3 * 60 * 60;
            break;
        case ABR_TO_INT('W', 'A', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = 1 * 60 * 60;
            break;
        case ABR_TO_INT('C', 'E', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = 1 * 60 * 60;
            break;
        case ABR_TO_INT('C', 'A', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = 2 * 60 * 60;
            break;
        case ABR_TO_INT4('C', 'E', 'D', 'T'):
        case ABR_TO_INT4('C', 'E', 'S', 'T'):
            PTIME_CONSUME(4, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = 2 * 60 * 60;
            break;
        case ABR_TO_INT('M', 'S', 'K'):
        case ABR_TO_INT('I', 'D', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = 3 * 60 * 60;
            break;
        case ABR_TO_INT('I', 'S', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = 5 * 60 * 60 + 30 * 60;
            break;
        case ABR_TO_INT('H', 'K', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = 8 * 60 * 60;
            break;
        case ABR_TO_INT('J', 'S', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = 9 * 60 * 60;
            break;
        case ABR_TO_INT('K', 'S', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = 9 * 60 * 60;
            break;
        case ABR_TO_INT('N', 'S', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -3 * 60 * 60 + 30 * 60;
            break;
        case ABR_TO_INT('N', 'D', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -2 * 60 * 60 + 30 * 60;
            break;
        case ABR_TO_INT('E', 'S', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -5 * 60 * 60;
            break;
        case ABR_TO_INT('E', 'D', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -4 * 60 * 60;
            break;
        case ABR_TO_INT('C', 'S', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -6 * 60 * 60;
            break;
        case ABR_TO_INT('C', 'D', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -5 * 60 * 60;
            break;
        case ABR_TO_INT('M', 'S', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -7 * 60 * 60;
            break;
        case ABR_TO_INT('M', 'D', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -6 * 60 * 60;
            break;
        case ABR_TO_INT('P', 'S', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -8 * 60 * 60;
            break;
        case ABR_TO_INT('P', 'D', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -7 * 60 * 60;
            break;
        case ABR_TO_INT('H', 'S', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -10 * 60 * 60;
            break;
        case ABR_TO_INT('A', 'S', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -4 * 60 * 60;
            break;
        case ABR_TO_INT('A', 'D', 'T'):
            PTIME_CONSUME(3, { dst->et_flags |= ETF_ZONE_SET; });
            dst->et_gmtoff = -3 * 60 * 60;
            break;
        default:
            return false;
    }
    return true;
}

#define FMT_CASE(ch, c) \
    case ch: \
        if (!ptime_##c(dst, str, off, len)) \
            return false; \
        lpc += 1; \
        break

bool
ptime_fmt(const char* fmt,
          struct exttm* dst,
          const char* str,
          off_t& off,
          ssize_t len)
{
    for (ssize_t lpc = 0; fmt[lpc]; lpc++) {
        if (fmt[lpc] == '%') {
            switch (fmt[lpc + 1]) {
                case 'B': {
                    size_t b_len = len - off;
                    stack_buf allocator;
                    auto* full_month = allocator.allocate(b_len + 1);
                    const char* end_of_date;

                    memcpy(full_month, &str[off], b_len);
                    full_month[b_len] = '\0';
                    if ((end_of_date = strptime(full_month, "%B", &dst->et_tm))
                        != nullptr)
                    {
                        off += end_of_date - full_month;
                        lpc += 1;
                    } else {
                        return false;
                    }
                    break;
                }
                case 'a':
                case 'Z':
                    if (fmt[lpc + 2]) {
                        if (!ptime_upto(fmt[lpc + 2], str, off, len)) {
                            return false;
                        }
                        lpc += 1;
                    } else {
                        if (!ptime_upto_end(str, off, len)) {
                            return false;
                        }
                        lpc += 1;
                    }
                    break;
                    FMT_CASE('b', b);
                    FMT_CASE('S', S);
                    FMT_CASE('s', s);
                    FMT_CASE('L', L);
                    FMT_CASE('M', M);
                    FMT_CASE('H', H);
                    FMT_CASE('i', i);
                    FMT_CASE('6', 6);
                    FMT_CASE('9', 9);
                    FMT_CASE('I', I);
                    FMT_CASE('d', d);
                    FMT_CASE('e', e);
                    FMT_CASE('j', j);
                    FMT_CASE('f', f);
                    FMT_CASE('k', k);
                    FMT_CASE('l', l);
                    FMT_CASE('m', m);
                    FMT_CASE('N', N);
                    FMT_CASE('p', p);
                    FMT_CASE('q', q);
                    FMT_CASE('Y', Y);
                    FMT_CASE('y', y);
                    FMT_CASE('z', z);
                    FMT_CASE('@', at);
            }
        } else {
            if (!ptime_char(fmt[lpc], str, off, len)) {
                return false;
            }
        }
    }

    return true;
}

#define FTIME_FMT_CASE(ch, c) \
    case ch: \
        ftime_##c(dst, off_inout, len, tm); \
        lpc += 1; \
        break

size_t
ftime_fmt(char* dst, size_t len, const char* fmt, const struct exttm& tm)
{
    off_t off_inout = 0;

    for (ssize_t lpc = 0; fmt[lpc]; lpc++) {
        if (fmt[lpc] == '%') {
            switch (fmt[lpc + 1]) {
                case '%':
                    ftime_char(dst, off_inout, len, '%');
                    break;
                    FTIME_FMT_CASE('a', a);
                    FTIME_FMT_CASE('b', b);
                    FTIME_FMT_CASE('S', S);
                    FTIME_FMT_CASE('s', s);
                    FTIME_FMT_CASE('L', L);
                    FTIME_FMT_CASE('M', M);
                    FTIME_FMT_CASE('H', H);
                    FTIME_FMT_CASE('i', i);
                    FTIME_FMT_CASE('6', 6);
                    FTIME_FMT_CASE('9', 9);
                    FTIME_FMT_CASE('I', I);
                    FTIME_FMT_CASE('d', d);
                    FTIME_FMT_CASE('e', e);
                    FTIME_FMT_CASE('j', j);
                    FTIME_FMT_CASE('f', f);
                    FTIME_FMT_CASE('k', k);
                    FTIME_FMT_CASE('l', l);
                    FTIME_FMT_CASE('m', m);
                    FTIME_FMT_CASE('N', N);
                    FTIME_FMT_CASE('p', p);
                    FTIME_FMT_CASE('q', q);
                    FTIME_FMT_CASE('Y', Y);
                    FTIME_FMT_CASE('y', y);
                    FTIME_FMT_CASE('z', z);
            }
        } else {
            ftime_char(dst, off_inout, len, fmt[lpc]);
        }
    }

    dst[off_inout] = '\0';

    return (size_t) off_inout;
}
