// Copyright (c) 2021, Fr.Terrot. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file. 

package io.gitea.model;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.lang.StringUtils;
import org.eclipse.mylyn.tasks.core.ITask.PriorityLevel;

import io.gitea.StringUtil;

/**
 * Extract Mylyn PriorityLevel from Issue label
 * 
 */
public enum GiteaPriorityLevel {
    HIGHEST(PriorityLevel.P1), HIGH(PriorityLevel.P2), MIDDLE(PriorityLevel.P3), LOW(PriorityLevel.P4),
    LOWEST(PriorityLevel.P5);

    private PriorityLevel level;

    /**
     * Constructor.
     * 
     * @private
     */
    private GiteaPriorityLevel(PriorityLevel p) {
        this.level = p;
    }

    /**
     * Get GiteaPriority level.
     * 
     * @return PriorityLevel
     */
    public PriorityLevel getLevel() {
        return level;
    }

    /**
     * GiteaPriority level as String
     * 
     * {@code giteaPriority.ToString() <=> giteaPriority.GetLevel().toString()}
     * 
     * To Get GiteaPriority as String use standard Enum name() API.
     * 
     * @{code HIGHEST.toString() -> "P1" HIGHEST.name() -> "HIGHEST"}
     */
    public String toString() {
        return level.toString();
    }

    /**
     * Get GiteaPriority from PriorityLevel
     * 
     * @param level
     * @return
     * @throws IllegalArgumentException
     */
    public static GiteaPriorityLevel getPriority(PriorityLevel level) throws IllegalArgumentException {
        return Arrays.stream(values()).filter(v -> v.level.equals(level)).findFirst()
                .orElseThrow(() -> new IllegalArgumentException("unknown priority level:" + level.toString()));
    }

    // P1 .. P5 
    private static String valueRegex = "(?::?priority:)?(p[1-5])";
    private static Pattern valuePattern = Pattern.compile(valueRegex, Pattern.CASE_INSENSITIVE);
    // Xtra very_normal is supported, surprising but not a big issue, kept it regexp
    // 'simple'
    private static String alternativeRegex = "(?::?priority:)?(?:very_?)?(high|low|normal)";
    private static Pattern alternativePattern = Pattern.compile(alternativeRegex, Pattern.CASE_INSENSITIVE);
    
    private static String priorityRegex = "(?::?priority:)?(highest|middle|low|lowest)";
    private static Pattern priorityPattern = Pattern.compile(priorityRegex, Pattern.CASE_INSENSITIVE);
    
    private static String allPrioritiesRegex = "((?::?priority:)?(?:p[1-5]|(?:high|low)(?:est)?|(?:very_?)(?:high|low)|normal|middle))";
    private static Pattern allPrioritiesPattern = Pattern.compile(allPrioritiesRegex, Pattern.CASE_INSENSITIVE);


    /**
     * Return the Priority from labels value.
     * 
     * @param labels as string
     * 
     * @return found priority or MIDDLE if no priority found.
     */
    public static GiteaPriorityLevel getPriority(String labels) {

        Matcher m = priorityPattern.matcher(labels);
        if (m.find()) {
            return GiteaPriorityLevel.valueOf(m.group(1).toUpperCase());
        }
        m = valuePattern.matcher(labels);
        if (m.find()) {
            return GiteaPriorityLevel.getPriority(PriorityLevel.valueOf(m.group(1).toUpperCase()));
        }

        m = alternativePattern.matcher(labels);
        if (m.find()) {
            switch (m.group(1).toLowerCase()) {
            case "high":
                return GiteaPriorityLevel.HIGHEST;
            case "normal":
                return GiteaPriorityLevel.MIDDLE;
            case "low":
                return GiteaPriorityLevel.LOWEST;
            default:
            }
        }
        return GiteaPriorityLevel.MIDDLE;
    }

    /** Extract for the labels list the ones which are priority level.
     * 
     */
    public static List<String> getAllPriorityLabels(List<String> labels) {
    	List<String> priorities =  new ArrayList<String>();
    	labels.forEach((label) -> {
    		if (allPrioritiesPattern.matcher(label).find()) priorities.add(label);
    	});
    	return priorities;
    }
}