package com.example.resourceserver.security;

import java.security.Principal;
import java.util.Collection;
import java.util.Map;
import java.util.stream.Collectors;

import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.annotation.AuthenticationPrincipal;
import org.springframework.security.oauth2.jwt.Jwt;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/api/security/users")
public class UserRestController {
    private UserService userService;

    public UserRestController(UserService userService) {
        this.userService = userService;
    }

    /**
     * What is in Principal?
     * 
     * Note that we are returning the details just for testing (here and in some
     * other methods below). But what is typically done is not returning such
     * details but use the details within the method itself to determine who is the
     * calling user and the roles of that user.
     * 
     * @param principal
     * @return
     */
    @GetMapping("/test")
    public String test(Principal principal) {
        return principal.toString();
    }

    /**
     * principal.getName() returns the OAuth2 authenticated user name. Can be
     * trusted within this method.
     * 
     * @param principal
     * @return
     */
    @GetMapping("/test-username")
    public String testName(Principal principal) {
        return principal.getName();
    }

    /**
     * Roles returned by authentication.getAuthorities() may not always have custom
     * roles.
     * 
     * @param authentication
     * @return
     */
    @GetMapping("/test-roles-auth")
    public Collection<String> getRoles(Authentication authentication) {
        return authentication.getAuthorities().stream()
                .map(GrantedAuthority::getAuthority)
                .collect(Collectors.toList());
    }

    /**
     * Inspect raw JWT claims directly.
     * 
     * @param jwt
     * @return
     */
    @GetMapping("/test-roles-jwt")
    public Map<String, Object> getClaims(@AuthenticationPrincipal Jwt jwt) {
        return jwt.getClaims(); // Extract custom JSON fields containing roles
    }

    /**
     * Within a method, use the X-User-Roles HTTP header to determine the user
     * roles.
     * 
     * Not very secure because unverifiable headers may be introduced by attackers.
     * So to trust the roles so received, this service should have been
     * deployed in an access restricted network environment.
     */
    @GetMapping("/test-roles-headers")
    public String getRolesFromHeaders(@RequestHeader("X-User-Name") String username,
            @RequestHeader("X-User-Roles") String roles) {
        return "Roles: " + roles + ", username: " + username;
    }
}