package cn.ibizlab.businesscentral.util.security;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Clock;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.impl.DefaultClock;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.core.context.SecurityContext;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;
import org.springframework.boot.autoconfigure.condition.ConditionalOnExpression;
import java.io.Serializable;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.function.Function;

@Component
@ConditionalOnExpression("(!${ibiz.enablePermissionValid:false})&&'${ibiz.auth.token.util:SimpleTokenUtil}'.equals('SimpleTokenUtil')")
public class SimpleTokenUtil implements AuthTokenUtil,Serializable {

    private static final long serialVersionUID = -3301605591108950415L;
    private Clock clock = DefaultClock.INSTANCE;

    @Value("${ibiz.jwt.secret:ibzsecret}")
    private String secret;

    @Value("${ibiz.jwt.expiration:7200000}")
    private Long expiration;

    @Value("${ibiz.jwt.header:Authorization}")
    private String tokenHeader;

    public String getUsernameFromToken(String token) {
        return getClaimFromToken(token, Claims::getSubject);
    }

    public Date getIssuedAtDateFromToken(String token) {
        return getClaimFromToken(token, Claims::getIssuedAt);
    }

    public Date getExpirationDateFromToken(String token) {
        return getClaimFromToken(token, Claims::getExpiration);
    }

    public <T> T getClaimFromToken(String token, Function<Claims, T> claimsResolver) {
        final Claims claims = getAllClaimsFromToken(token);
        return claimsResolver.apply(claims);
    }

    private Claims getAllClaimsFromToken(String token) {
        return Jwts.parser()
                .setSigningKey(secret)
                .parseClaimsJws(token)
                .getBody();
    }

    private Boolean isTokenExpired(String token) {
        final Date expiration = getExpirationDateFromToken(token);
        return expiration.before(clock.now());
    }

    private Boolean isCreatedBeforeLastPasswordReset(Date created, Date lastPasswordReset) {
        return (lastPasswordReset != null && created.before(lastPasswordReset));
    }

    private Boolean ignoreTokenExpiration(String token) {
        // here you specify tokens, for that the expiration is ignored
        return false;
    }

    public String generateToken(UserDetails userDetails) {
        Map<String, Object> claims = new HashMap<>();
        return doGenerateToken(claims, userDetails.getUsername());
    }

    private String doGenerateToken(Map<String, Object> claims, String subject) {
        final Date createdDate = clock.now();
        final Date expirationDate = calculateExpirationDate(createdDate);

        return Jwts.builder()
                .setClaims(claims)
                .setSubject(subject)
                .setIssuedAt(createdDate)
                .setExpiration(expirationDate)
                .signWith(SignatureAlgorithm.HS512, secret)
                .compact();
    }

    public Boolean canTokenBeRefreshed(String token, Date lastPasswordReset) {
        final Date created = getIssuedAtDateFromToken(token);
        return !isCreatedBeforeLastPasswordReset(created, lastPasswordReset)
                && (!isTokenExpired(token) || ignoreTokenExpiration(token));
    }

    public String refreshToken(String token) {
        final Date createdDate = clock.now();
        final Date expirationDate = calculateExpirationDate(createdDate);

        final Claims claims = getAllClaimsFromToken(token);
        claims.setIssuedAt(createdDate);
        claims.setExpiration(expirationDate);

        return Jwts.builder()
                .setClaims(claims)
                .signWith(SignatureAlgorithm.HS512, secret)
                .compact();
    }

    public Boolean validateToken(String token, UserDetails userDetails) {
        AuthenticationUser user = (AuthenticationUser) userDetails;
        final Date created = getIssuedAtDateFromToken(token);
        return (!isTokenExpired(token) );
    }

    private Date calculateExpirationDate(Date createdDate) {
        return new Date(createdDate.getTime() + expiration);
    }

    /**
     * Get the login of the current user.
     *
     * @return the login of the current user
     */
    public static Optional<String> getCurrentUserLogin() {
        SecurityContext securityContext = SecurityContextHolder.getContext();
        return Optional.ofNullable(securityContext.getAuthentication())
                .map(authentication -> {
                    if (authentication.getPrincipal() instanceof UserDetails) {
                        UserDetails springSecurityUser = (UserDetails) authentication.getPrincipal();
                        return springSecurityUser.getUsername();
                    } else if (authentication.getPrincipal() instanceof String) {
                        return (String) authentication.getPrincipal();
                    }
                    return null;
                });
    }

    /**
     * Check if a user is authenticated.
     *
     * @return true if the user is authenticated, false otherwise
     */
    public static boolean isAuthenticated() {
        SecurityContext securityContext = SecurityContextHolder.getContext();
        return Optional.ofNullable(securityContext.getAuthentication())
                .map(authentication -> authentication.getAuthorities().stream()
                        .noneMatch(grantedAuthority -> grantedAuthority.getAuthority().equals("ANONYMOUS")))
                .orElse(false);
    }

    /**
     * If the current user has a specific authority (security role).
     * <p>
     * The name of this method comes from the isUserInRole() method in the Servlet API
     *
     * @param authority the authority to check
     * @return true if the current user has the authority, false otherwise
     */
    public static boolean isCurrentUserInRole(String authority) {
        SecurityContext securityContext = SecurityContextHolder.getContext();
        return Optional.ofNullable(securityContext.getAuthentication())
                .map(authentication -> authentication.getAuthorities().stream()
                        .anyMatch(grantedAuthority -> grantedAuthority.getAuthority().equals(authority)))
                .orElse(false);
    }
}

