package com.goi.erp.auth;

import jakarta.servlet.http.Cookie;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

import java.util.Arrays;
import java.util.Optional;

@Service
public class AuthCookieService {

    public static final String AUTH_COOKIE_NAME = "AUTH_TOKEN";
    public static final String REFRESH_COOKIE_NAME = "REFRESH_TOKEN";

    @Value("${auth.cookie.secure:true}")
    private boolean secure;

    @Value("${auth.cookie.same-site:Lax}")
    private String sameSite;

    @Value("${auth.cookie.path:/}")
    private String path;

    // ===================== Access Token =====================

    public void addAuthCookie(HttpServletResponse response, String jwt) {
        addCookie(response, AUTH_COOKIE_NAME, jwt, -1);
    }

    public void clearAuthCookie(HttpServletResponse response) {
        addCookie(response, AUTH_COOKIE_NAME, null, 0);
    }

    public Optional<String> extractJwt(HttpServletRequest request) {
        return extractCookie(request, AUTH_COOKIE_NAME);
    }

    // ===================== Refresh Token =====================

    public void addRefreshCookie(HttpServletResponse response, String refreshToken) {
        addCookie(response, REFRESH_COOKIE_NAME, refreshToken, -1);
    }

    public void clearRefreshCookie(HttpServletResponse response) {
        addCookie(response, REFRESH_COOKIE_NAME, null, 0);
    }

    public Optional<String> extractRefreshToken(HttpServletRequest request) {
        return extractCookie(request, REFRESH_COOKIE_NAME);
    }

    // ===================== 내부 공통 =====================

    private void addCookie(
            HttpServletResponse response,
            String name,
            String value,
            int maxAge
    ) {
        Cookie cookie = new Cookie(name, value);
        cookie.setHttpOnly(true);
        cookie.setSecure(secure);
        cookie.setPath(path);
        cookie.setMaxAge(maxAge);

        response.addCookie(cookie);
        addSameSiteAttribute(response, cookie);
    }

    private Optional<String> extractCookie(HttpServletRequest request, String name) {
        if (request.getCookies() == null) {
            return Optional.empty();
        }

        return Arrays.stream(request.getCookies())
                .filter(c -> name.equals(c.getName()))
                .map(Cookie::getValue)
                .filter(v -> v != null && !v.isBlank())
                .findFirst();
    }

    /**
     * SameSite 수동 세팅 (Servlet Cookie API 한계)
     */
    private void addSameSiteAttribute(HttpServletResponse response, Cookie cookie) {
        StringBuilder sb = new StringBuilder();
        sb.append(cookie.getName()).append("=");
        sb.append(cookie.getValue() == null ? "" : cookie.getValue());
        sb.append("; Path=").append(cookie.getPath());
        sb.append("; HttpOnly");

        if (cookie.getSecure()) {
            sb.append("; Secure");
        }

        if (sameSite != null && !sameSite.isBlank()) {
            sb.append("; SameSite=").append(sameSite);
        }

        if (cookie.getMaxAge() == 0) {
            sb.append("; Max-Age=0");
        }

        response.addHeader("Set-Cookie", sb.toString());
    }
}