package cn.ibizlab.ehr.util.security;

import io.jsonwebtoken.ExpiredJwtException;
import lombok.extern.slf4j.Slf4j;
import cn.ibizlab.ehr.util.service.AuthenticationUserService;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.web.authentication.WebAuthenticationDetailsSource;
import org.springframework.stereotype.Component;
import org.springframework.web.filter.OncePerRequestFilter;
import org.springframework.beans.factory.annotation.Qualifier;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Slf4j
@Component
public class AuthorizationTokenFilter extends OncePerRequestFilter {

    private final UserDetailsService userDetailsService;
    private final AuthTokenUtil authTokenUtil;
    private final String tokenHeader;

    public AuthorizationTokenFilter(AuthenticationUserService userDetailsService, AuthTokenUtil authTokenUtil, @Value("${ibiz.jwt.header:Authorization}") String tokenHeader) {
        this.userDetailsService = userDetailsService;
        this.authTokenUtil = authTokenUtil;
        this.tokenHeader = tokenHeader;
    }

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws ServletException, IOException {

        final String requestHeader = request.getHeader(this.tokenHeader);

        String username = null;
        String authToken = null;
        if (requestHeader != null && requestHeader.startsWith("Bearer ")) {
            authToken = requestHeader.substring(7);
            try {
                username = authTokenUtil.getUsernameFromToken(authToken);
            } catch (ExpiredJwtException e) {
                log.error(e.getMessage());
            }
        }

        if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {

            // It is not compelling necessary to load the use details from the database. You could also store the information
            // in the token and read it from it. It's up to you ;)
            UserDetails userDetails = this.userDetailsService.loadUserByUsername(username);

            // For simple validation it is completely sufficient to just check the token integrity. You don't have to call
            // the database compellingly. Again it's up to you ;)
            if (authTokenUtil.validateToken(authToken, userDetails)) {
                UsernamePasswordAuthenticationToken authentication = new UsernamePasswordAuthenticationToken(userDetails, null, userDetails.getAuthorities());
                authentication.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
                log.info("authorizated user '{}', setting security context", username);
                SecurityContextHolder.getContext().setAuthentication(authentication);
            }
        }
        chain.doFilter(request, response);
    }
}
