package org.gcube.oidc.rest;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Base64;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class JWTToken implements Serializable {

    protected static Logger logger = LoggerFactory.getLogger(JWTToken.class);

    private static final long serialVersionUID = -7063122428186284827L;

    public static final String ACCOUNT_RESOURCE = "account";

    private String raw;
    private JSONObject token;
    private JSONObject payload;

    public static JWTToken fromString(String tokenString) {
        if (tokenString == null) {
            logger.debug("Token string is null, cannot create token object");
            return null;
        }
        try {
            return new JWTToken(tokenString);
        } catch (ParseException e) {
            logger.error("Cannot parse token string", e);
            return null;
        }
    }

    private JWTToken(String raw) throws ParseException {
        this.raw = raw;
        this.parse();
    }

    private void parse() throws ParseException {
        token = (JSONObject) new JSONParser().parse(this.raw);
        String[] parts = getAccessTokenString().split("\\.");
        payload = (JSONObject) new JSONParser().parse(new String(Base64.getDecoder().decode(parts[1])));
    }

    public String getRaw() {
        return raw;
    }

    public String getAccessTokenString() {
        return (String) token.get("access_token");
    }

    public String getRefreshTokenString() {
        return (String) token.get("refresh_token");
    }

    /**
     * @deprecated Use {@link #getAccessTokenAsBearer()} method instead
     * @return
     */
    @Deprecated()
    public String getAsBearer() {
        return getAccessTokenAsBearer();
    }

    public String getAccessTokenAsBearer() {
        return "Bearer " + getAccessTokenString();
    }

    public JSONObject getPayload() {
        return payload;
    }

    public String getAzp() {
        return (String) getPayload().get("azp");
    }

    public Long getExp() {
        return (Long) getPayload().get("exp");
    }

    public Date getExpAsDate() {
        return new Date(getExp() * 1000);
    }

    public Calendar getExpAsCalendar() {
        Calendar cal = Calendar.getInstance();
        cal.setTime(getExpAsDate());
        return cal;
    }

    public boolean isExpired() {
        return new Date().after(getExpAsDate());
    }

    public List<String> getAud() {
        List<String> audienceStrings = new ArrayList<>();
        Object audience = getPayload().get("aud");
        if (audience instanceof String) {
            audienceStrings.add((String) audience);
        } else if (audience instanceof JSONArray) {
            JSONArray audienceArray = (JSONArray) audience;
            for (int i = 0; i < audienceArray.size(); i++) {
                audienceStrings.add((String) audienceArray.get(i));
            }
        }
        return audienceStrings;
    }

    public String getSub() {
        return (String) getPayload().get("sub");
    }

    public String getEmail() {
        return (String) getPayload().get("email");
    }

    public String getFamily() {
        return (String) getPayload().get("family_name");
    }

    public String getGiven() {
        return (String) getPayload().get("given_name");
    }

    public String getUserName() {
        return (String) getPayload().get("preferred_username");
    }

    public String getDisplayName() {
        return (String) getPayload().get("name");
    }

    protected JSONObject getResourceAccess() {
        return (JSONObject) getPayload().get("resource_access");
    }

    @SuppressWarnings("unchecked")
    protected Iterator<String> getResourceAccessKeys() {
        return getResourceAccess().keySet().iterator();
    }

    public List<String> getResourceAccessRoles(String resource) {
        JSONArray rolesJsonArray = (JSONArray) ((JSONObject) getResourceAccess().get(resource))
                .get("roles");
        List<String> roles = new ArrayList<>(rolesJsonArray.size());
        for (int i = 0; i < rolesJsonArray.size(); i++) {
            roles.add((String) rolesJsonArray.get(i));
        }
        return roles;
    }

    public Map<String, List<String>> getResourceNameToAccessRolesMap(List<String> resourcesToSkip) {
        Map<String, List<String>> map = new HashMap<>();
        Iterator<String> resourcesIterator = getResourceAccessKeys();
        while (resourcesIterator.hasNext()) {
            String resource = resourcesIterator.next();
            if (resourcesToSkip.contains(resource)) {
                continue;
            }
            map.put(resource, getResourceAccessRoles(resource));
        }
        return map;
    }

    protected JSONArray getAuthorizationPermissions() {
        JSONObject authorization = (JSONObject) getPayload().get("authorization");
        return (JSONArray) authorization.get("permissions");
    }

    public List<String> getAuthorizationPermissionRSNames() {
        List<String> permissionsRSName = new ArrayList<>();
        JSONArray permissions = getAuthorizationPermissions();
        for (int i = 0; i < permissions.size(); i++) {
            JSONObject permissionsEntry = (JSONObject) permissions.get(i);
            permissionsRSName.add((String) permissionsEntry.get("rsname"));
        }
        return permissionsRSName;
    }

    public List<String> getAuthorizationPermissionRSNameResourceScopes(String rsname) {
        List<String> scopes = new ArrayList<>();
        JSONArray permissions = getAuthorizationPermissions();
        for (int i = 0; i < permissions.size(); i++) {
            JSONObject permissionsEntry = (JSONObject) permissions.get(i);
            if (rsname.equals(permissionsEntry.get("rsname"))) {
                JSONArray scopesJsonArray = (JSONArray) permissionsEntry.get("resource_scopes");
                if (scopesJsonArray != null) {
                    for (int j = 0; j < scopesJsonArray.size(); j++) {
                        scopes.add((String) scopesJsonArray.get(j));
                    }
                }
            }
        }
        return scopes;
    }

    public Map<String, List<String>> getAuthorizationPermissionRSNameToResourceScopesMap() {
        Map<String, List<String>> map = new HashMap<>();
        for (String aprn : getAuthorizationPermissionRSNames()) {
            map.put(aprn, getAuthorizationPermissionRSNameResourceScopes(aprn));
        }
        return map;
    }

    @Override
    public String toString() {
        return getRaw();
    }

}