package com.stylefeng.guns.rest.auth;

import com.stylefeng.guns.rest.config.properties.JwtProperties;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mobile.device.Device;
import org.springframework.stereotype.Component;

import java.io.Serializable;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;

@Component
public class JwtTokenUtil implements Serializable {

    @Autowired
    private JwtProperties jwtProperties;

    private static final long serialVersionUID = -3301605591108950415L;

    static final String CLAIM_KEY_USERNAME = "sub";
    static final String CLAIM_KEY_AUDIENCE = "aud";
    static final String CLAIM_KEY_CREATED = "iat";

    static final String AUDIENCE_UNKNOWN = "unknown";
    static final String AUDIENCE_WEB = "web";
    static final String AUDIENCE_MOBILE = "mobile";
    static final String AUDIENCE_TABLET = "tablet";

    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 String getAudienceFromToken(String token) {
        return getClaimFromToken(token, Claims::getAudience);
    }

    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(jwtProperties.getSecret())
                .parseClaimsJws(token)
                .getBody();
    }

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

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

    private String generateAudience(Device device) {
        String audience = AUDIENCE_UNKNOWN;
        if (device.isNormal()) {
            audience = AUDIENCE_WEB;
        } else if (device.isTablet()) {
            audience = AUDIENCE_TABLET;
        } else if (device.isMobile()) {
            audience = AUDIENCE_MOBILE;
        }
        return audience;
    }

    private Boolean ignoreTokenExpiration(String token) {
        String audience = getAudienceFromToken(token);
        return (AUDIENCE_TABLET.equals(audience) || AUDIENCE_MOBILE.equals(audience));
    }

    public String generateToken(String userName, Device device) {
        Map<String, Object> claims = new HashMap<>();
        return doGenerateToken(claims, userName, generateAudience(device));
    }

    private String doGenerateToken(Map<String, Object> claims, String subject, String audience) {
        final Date createdDate = new Date();
        final Date expirationDate = new Date(createdDate.getTime() + jwtProperties.getExpiration() * 1000);

        System.out.println("doGenerateToken " + createdDate);

        return Jwts.builder()
                .setClaims(claims)
                .setSubject(subject)
                .setAudience(audience)
                .setIssuedAt(createdDate)
                .setExpiration(expirationDate)
                .signWith(SignatureAlgorithm.HS512, jwtProperties.getSecret())
                .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 Claims claims = getAllClaimsFromToken(token);
        claims.setIssuedAt(new Date());
        return doRefreshToken(claims);
    }

    public String doRefreshToken(Claims claims) {
        return Jwts.builder()
                .setClaims(claims)
                .signWith(SignatureAlgorithm.HS512, jwtProperties.getSecret())
                .compact();
    }

    public Boolean validateToken(String token, String userName) {
        final String username = getUsernameFromToken(token);
        final Date created = getIssuedAtDateFromToken(token);
        //final Date expiration = getExpirationDateFromToken(token);
        return (
                username.equals(userName)
                        && !isTokenExpired(token));
    }
}