/*
   The MIT License (MIT)
   -----------------------------------------------------------------------------

   Copyright (c) 2015 javafx.ninja <info@javafx.ninja>

   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files (the "Software"), to deal
   in the Software without restriction, including without limitation the rights
   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   copies of the Software, and to permit persons to whom the Software is
   furnished to do so, subject to the following conditions:

   The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   THE SOFTWARE.

*/

package ninja.javafx.smartcsv.validation;

import com.typesafe.config.Config;
import groovy.lang.Binding;
import groovy.lang.GroovyShell;
import groovy.lang.Script;
import org.codehaus.groovy.control.CompilationFailedException;

import java.util.HashMap;
import java.util.Map;

import static org.apache.commons.validator.GenericValidator.*;

/**
 * This class checks all the validations defined in the
 * Config against a given value
 */
public class Validator {

    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    // member variables
    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

    private Config validationConfig;
    private GroovyShell shell = new GroovyShell();
    private Map<String, Script> scriptCache = new HashMap<>();


    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    // constructors
    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

    /**
     * JSON configuration for this validator
     * @param validationConfig
     */
    public Validator(Config validationConfig) {
         this.validationConfig = validationConfig;
    }


    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    // oublic methods
    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

    /**
     * checks if the value is valid for the column configuration
     * @param column the column name
     * @param value the value to check
     * @return ValidationState with information if valid and if not which error happened
     */
    public ValidationState isValid(String column, String value) {
        ValidationState result = new ValidationState();
        if (validationConfig != null) {
            Config columnConfig = getColumnConfig(column);
            if (columnConfig != null) {
                checkBlankOrNull(columnConfig, value, result);
                if (value != null) {
                    checkRegularExpression(columnConfig, value, result);
                    checkAlphaNumeric(columnConfig, value, result);
                    checkDate(columnConfig, value, result);
                    checkMaxLength(columnConfig, value, result);
                    checkMinLength(columnConfig, value, result);
                    checkInteger(columnConfig, value, result);
                    checkGroovy(column, columnConfig, value, result);
                }
            }
        }
        return result;
    }


    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    // private methods
    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

    private void checkGroovy(String column, Config columnConfig, String value, ValidationState result) {
        String groovyScript = getString(columnConfig, "groovy");
        if (groovyScript != null) {

            Script script = scriptCache.get(column);
            if (script == null) {
                script = shell.parse(groovyScript);
                scriptCache.put(column, script);
            }

            Binding binding = new Binding();
            binding.setVariable("value", value);
            script.setBinding(binding);

            Object groovyResult = null;
            try {
                groovyResult = script.run();
            } catch (CompilationFailedException e) {
                result.invalidate("groovy script '"+groovyScript+"' throws exception: "+e.getMessage());
                e.printStackTrace();
            }
            if (groovyResult == null) {
                result.invalidate("groovy script '"+groovyScript+"' returns null");
            }

            if (!isScriptResultTrue(groovyResult)) {
                result.invalidate(groovyResult.toString());
            }

        }
    }

    private boolean isScriptResultTrue(Object groovyResult) {
        return groovyResult.equals(true) || groovyResult.toString().trim().toLowerCase().equals("true");
    }

    private void checkBlankOrNull(Config columnConfig, String value, ValidationState result) {
        if (getBoolean(columnConfig, "not empty")) {
            if (isBlankOrNull(value)) {
                result.invalidate("should not be empty");
            }
        }
    }

    private void checkInteger(Config columnConfig, String value, ValidationState result) {
        if (getBoolean(columnConfig, "integer")) {
            if (!isInt(value)) {
                result.invalidate("should be an integer");
            }
        }
    }

    private void checkMinLength(Config columnConfig, String value, ValidationState result) {
        Integer minLength = getInteger(columnConfig, "minlength");
        if (minLength != null) {
            if (!minLength(value, minLength)) {
                result.invalidate("has not min length of " + minLength);
            }
        }
    }

    private void checkMaxLength(Config columnConfig, String value, ValidationState result) {
        Integer maxLength = getInteger(columnConfig, "maxlength");
        if (maxLength != null) {
            if (!maxLength(value, maxLength)) {
                result.invalidate("has not max length of " + maxLength);
            }
        }
    }

    private void checkDate(Config columnConfig, String value, ValidationState result) {
        String dateformat = getString(columnConfig, "date");
        if (dateformat != null && !dateformat.trim().isEmpty()) {
            if (!isDate(value, dateformat, true)) {
                result.invalidate("is not a date of format " + dateformat);
            }
        }
    }

    private void checkAlphaNumeric(Config columnConfig, String value, ValidationState result) {
        if (getBoolean(columnConfig, "alphanumeric")) {
            if (!matchRegexp(value, "[0-9a-zA-Z]*")) {
                result.invalidate("should not be alphanumeric");
            }
        }
    }

    private void checkRegularExpression(Config columnConfig, String value, ValidationState result) {
        String regexp = getString(columnConfig, "regexp");
        if (regexp != null && !regexp.trim().isEmpty()) {
            if (!matchRegexp(value, regexp)) {
                result.invalidate("does not match " + regexp);
            }
        }
    }

    private Config getColumnConfig(String column) {
        return validationConfig.hasPath(column) ? validationConfig.getConfig(column) : null;
    }

    private String getString(Config columnConfig, String path) {
        return columnConfig.hasPath(path) ? columnConfig.getString(path) : null;
    }

    private Integer getInteger(Config columnConfig, String path) {
        return columnConfig.hasPath(path) ? columnConfig.getInt(path) : null;
    }


    private boolean getBoolean(Config columnConfig, String path) {
        return columnConfig.hasPath(path) && columnConfig.getBoolean(path);
    }

}