#include "flags.h"
#include <algorithm>
#include <arpa/nameser.h>
#include <assert.h>
#include <cstdio>
#include <cstring>
#include <idn2.h>
#include <map>
#include <netdb.h>
#include <netinet/in.h>
#include <resolv.h>
#include <set>
#include <string>
#include <string_view>
extern "C" {
#include <libknot/packet/pkt.h>
#include <libknot/rrtype/rdname.h>
}

using namespace std::literals;


static void htmlescape(const std::string_view & data) {
	for(auto c : data)
		switch(c) {
			case '<':
				std::fputs("&lt;", stdout);
				break;
			case '&':
				std::fputs("&amp;", stdout);
				break;
			default:
				std::fputc(c, stdout);
				break;
		}
}

static void singleescape(const std::string_view & data) {
	for(auto c : data)
		switch(c) {
			case '\'':
				std::fputs("%27", stdout);
				break;
			default:
				std::fputc(c, stdout);
				break;
		}
}


enum class tp : bool { a, mx };
enum class line_state_t : std::uint8_t { none, ptr, soa, hinfo };


int main(int, char ** names) {
	struct __res_state state;
	assert(!res_ninit(&state));

	std::map<std::string_view, tp> cache;
	unsigned char buf[NS_MAXMSG];
	for(auto itr = names + 1; *itr; ++itr)
		if(res_nquery(&state, *itr, ns_c_in, ns_t_a, buf, sizeof(buf)) != -1 || res_nquery(&state, *itr, ns_c_in, ns_t_aaaa, buf, sizeof(buf)) != -1)
			cache[*itr] = tp::a;
		else if(auto sz = res_nquery(&state, *itr, ns_c_in, ns_t_mx, buf, sizeof(buf)); sz != -1) {
			bool dont = false;
			if(auto pkt = knot_pkt_new(buf, sz, nullptr)) {
				if(auto p = knot_pkt_parse(pkt, 0); (p == KNOT_EOK || p == KNOT_ETRAIL) && pkt->sections[KNOT_ANSWER].count == 1) {
					auto mx = knot_pkt_rr(&pkt->sections[KNOT_ANSWER], 0);
					if(mx->rrs.count) {
						if(!*knot_rdata_name(mx->rrs.rdata, mx->type) && !std::memcmp(mx->rrs.rdata->data, "\0\0", 2))  // == "." && == 0
							dont = true;
						// fwrite(mx->rrs.rdata->data, 1, mx->rrs.rdata->len, stderr);
					}
				}
				knot_pkt_free(pkt);
			}
			if(!dont)
				cache[*itr] = tp::mx;
		}


	std::set<std::string> ids;
	char * line_raw{};
	std::size_t linecap{};
	auto line_state = line_state_t::none;
	for(ssize_t len; (len = getline(&line_raw, &linecap, stdin)) != -1;) {
		std::string_view line{line_raw, static_cast<std::size_t>(len)}, append;
		if(line.back() == '\n')
			line.remove_suffix(1);
		while(line.back() == ' ')
			line.remove_suffix(1);

		if(line.empty()) {
			if(line_state == line_state_t::ptr)
				std::fputs("</details>", stdout);
			goto dump;
		}

		if(line.starts_with(";;"sv)) {
			if(line.ends_with("  IN  PTR"sv)) {
				std::fputs("<details id='IN_PTR' open><summary>", stdout);
				append     = "</summary>"sv;
				line_state = line_state_t::ptr;
			} else if(line.ends_with("  IN  SOA"sv)) {
				append     = "<span id='IN_SOA'></span>"sv;
				line_state = line_state_t::soa;
			} else if(line.ends_with("  IN  HINFO"sv)) {
				append     = "<span id='IN_HINFO'></span>"sv;
				line_state = line_state_t::hinfo;
			} else
				line_state = line_state_t::none;
			goto dump;
		}

		if(line_state == line_state_t::ptr && line.starts_with(' ')) {
			line.remove_prefix(line.find_first_not_of(' '));
			if(line.starts_with("<del>;"sv)) {
				std::fwrite(line.data(), 1, line.size(), stdout);
				continue;
			}
		}

		// ;;zones.hinfo.network.               IN  SOA
		// zones.hinfo.network.          3600   IN  SOA    ns.nabijaczleweli.xyz. наб.hinfo.network. 2023-09-18T00:00:09+02:00
		if(line_state == line_state_t::soa && line.contains("  IN  SOA  "sv)) {
			auto mail = line;
			mail.remove_prefix(mail.find_first_of(' '));
			mail.remove_prefix(mail.find_first_not_of(' '));
			mail.remove_prefix(mail.find_first_of(' '));
			mail.remove_prefix(mail.find_first_not_of(' '));
			mail.remove_prefix(mail.find_first_of(' '));
			mail.remove_prefix(mail.find_first_not_of(' '));
			mail.remove_prefix(mail.find_first_of(' '));
			mail.remove_prefix(mail.find_first_not_of(' '));
			mail.remove_prefix(mail.find_first_of(' '));
			mail.remove_prefix(mail.find_first_not_of(' '));

			mail.remove_suffix(mail.size() - mail.find_first_of(' '));

			htmlescape({line.data(), mail.data()});
			std::fputs("<a href='mailto:", stdout);
			auto at       = mail.find('.');
			auto basename = std::string_view{mail.data(), at};
			singleescape(basename);
			std::fputc('@', stdout);
			singleescape({mail.data() + at + 1, mail.size() - at - 1});
			if(std::any_of(std::begin(basename), std::end(basename), [](auto c) { return c < ' ' || c > '~'; })) {
				char * out{};
				if(auto rc = idn2_to_ascii_8z(std::string{basename}.c_str(), &out, IDN2_NONTRANSITIONAL | IDN2_NFC_INPUT); rc != IDN2_OK)
					std::fputs(idn2_strerror(rc), stderr);
				if(out) {
					std::fputs("' title='Or ", stdout);
					singleescape(out);
					std::fputs("@", stdout);
				}
			}
			std::fputs("'>", stdout);
			htmlescape(mail);
			std::fputs("</a>", stdout);
			line = {mail.data() + mail.size(), line.data() + line.size()};
		}

		// ;;ibid.                              IN  HINFO
		// hinfo.group.                  60267  IN  HINFO  "X32" "DEBIAN/BOOKWORM"
		if(line_state == line_state_t::hinfo && line.contains("  IN  HINFO  "sv)) {
			if(line.back() == '\n')
				line.remove_suffix(1);
			while(line.back() == ' ')
				line.remove_suffix(1);

			auto flags = *reinterpret_cast<const std::uint8_t *>(&line.back());
			if(flags & f_CANARY) {
				line.remove_suffix(1);
				std::fputs("<del>", stdout);
			}

			auto sp   = line.find(' ');
			auto name = line;
			name.remove_suffix(line.size() - sp);
			if(auto type = cache.find(name); type != std::end(cache)) {
				line.remove_prefix(sp);

				switch(type->second) {
					case tp::a:
						std::fputs("<a href='//", stdout);
						break;
					case tp::mx:
						std::fputs("<a href='mailto:hostmaster@", stdout);
						break;
				}
				singleescape(name);
				if(type->second == tp::mx)
					std::fputs("?subject=Cool host!", stdout);
				std::fputs("'>", stdout);
				htmlescape(name);
				std::fputs("</a>", stdout);
			}

			htmlescape(line);
			line = {};

			if(flags & f_CANARY) {
				auto note = [&](auto shrt, auto lng) {
					std::fputs(" <abbr title='", stdout);
					std::fputs(lng, stdout);
					std::fputs("'>", stdout);
					std::fputs(shrt, stdout);
					std::fputs("</abbr>", stdout);
				};
				if(flags & f_fcount)
					note("FC", "Field Count");
				if(flags & f_cpulen)
					note("CL", "CPU Length");
				if(flags & f_syslen)
					note("SL", "System Length");
				if(flags & f_cpunvl)
					note("CN", "CPU Invalid");
				if(flags & f_sysnvl)
					note("SN", "System Invalid");

				std::fputs("</del>", stdout);
			}

			for(std::size_t dot; (dot = name.find('.')) != std::string_view::npos;) {
				if(ids.emplace(name).second) {
					std::fputs("<span id='", stdout);
					singleescape(name);
					std::fputs("'></span>", stdout);
				}
				name.remove_prefix(dot + 1);
			}
		}

	dump:
		htmlescape(line);
		std::fwrite(append.data(), 1, append.size(), stdout);
		std::fputc('\n', stdout);
	}
}