#include <string>
#include <stdexcept>
#include "settings.h"

static void set_settings(std::string_view str, const char* delimiter, UserSettings& settings);
static inline bool lowercase_compare(std::string_view lhs, std::string_view rhs);
static bool parse_bool(std::string_view value);


void UserSettings::set(std::string_view key, std::string_view value) {
    if (key == "auto-open-cw") {
        this->auto_open_cw = parse_bool(value);
    }
}

void UserSettings::load_from_cookies(const httplib::Request& req) {
    for (const auto& i : req.headers) {
        if (lowercase_compare(i.first, "cookie")) {
            set_settings(i.second, "; ", *this);
        }
    }
}


static void set_settings(std::string_view str, const char* delimiter, UserSettings& settings) {
    using namespace std::string_literals;
    size_t offset = 0;
    size_t new_offset = 0;
    size_t delimiter_len = strlen(delimiter);

    while (offset < str.size()) {
        new_offset = str.find(delimiter, offset);

        std::string_view item = str.substr(offset, new_offset != std::string_view::npos ? new_offset - offset : std::string_view::npos);
        size_t equal_offset = item.find('=');
        if (equal_offset == std::string_view::npos) {
            throw std::invalid_argument("invalid user setting item: "s + std::string(item));
        }
        settings.set(item.substr(0, equal_offset), item.substr(equal_offset + 1));

        if (new_offset == std::string_view::npos) {
            break;
        }
        offset = new_offset + delimiter_len;
    }
}

static inline bool lowercase_compare(std::string_view lhs, std::string_view rhs) {
    if (lhs.size() != rhs.size()) {
        return false;
    }

    auto lower = [](char c) {
        return c >= 'A' && c <= 'Z' ? c - 'A' + 'a' : c;
    };
    for (size_t i = 0; i < lhs.size(); i++) {
        if (lower(lhs[i]) != lower(rhs[i])) {
            return false;
        }
    }

    return true;
}

static bool parse_bool(std::string_view value) {
    using namespace std::string_literals;

    if (value == "true") {
        return true;
    } else if (value == "false") {
        return false;
    } else {
        throw std::invalid_argument("unknown boolean value: "s + std::string(value));
    }
}