//! See [Houdini](https://github.com/vmg/houdini/blob/master/houdini_html_e.c) for where this code
//! originally came from.
#include <base/html_escape.hpp>

// clang-format off
constexpr static u8 HTML_ESCAPE_TABLE[] = {
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 1, 0, 0, 0, 2, 3, 0, 0, 0, 0, 0, 0, 0, 4, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 6, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};

constexpr static std::string_view HTML_ESCAPES[] = {
        "",
        "&quot;",
        "&amp;",
        "&#39;",
        "&#47;",
        "&lt;",
        "&gt;"
};
// clang-format on

namespace base {
	std::string HtmlEscape(const std::span<u8> input) {
		std::string out;

		// TODO: rewrite this underlying implementation to be
		// UTF-8 safe, so we can allow UTF-8 input.

		for(auto& c : input) {
			const u8 escape = HTML_ESCAPE_TABLE[c];
			if(escape == 0) {
				out.push_back(c);
			} else {
				out += HTML_ESCAPES[escape];
			}
		}
		return out;
	}

	std::string HtmlEscape(const std::string_view input) {
		return HtmlEscape(std::span<u8> { std::bit_cast<u8*>(input.data()), input.length() });
	}

	std::string HtmlEscape(const std::string& input) {
		return HtmlEscape(std::span<u8> { std::bit_cast<u8*>(input.data()), input.length() });
	}
} // namespace base