SubwayTooter-Android-App/app/src/main/java/jp/juggler/subwaytooter/util/VersionString.kt

package jp.juggler.subwaytooter.util

import jp.juggler.util.asciiPattern
import jp.juggler.util.groupEx
import java.math.BigInteger
import java.util.ArrayList
import java.util.regex.Pattern

class VersionString(src : String?) : Comparable<VersionString> {
	
	private val src : String
	
	private val node_list = ArrayList<Any>()
	
	val isEmpty : Boolean
		get() = node_list.isEmpty()
	
	override fun toString() : String {
		return src
	}
	
	private class RC(val x : Int) : Comparable<RC> {
		override fun compareTo(other : RC) : Int {
			val i = x - other.x
			return if(i > 0) 1 else if(i < 0) - 1 else 0
		}
		
		override fun toString() : String {
			return "RC($x)"
		}
	}
	
	override fun compareTo(other : VersionString) : Int {
		return compare(this, other)
	}
	
	init {
		this.src = src ?: ""
		if(src?.isNotEmpty() == true) {
			val end = src.length
			var next = 0
			while(next < end) {
				var c = src[next]
				
				when {
					isDelimiter(c) -> {
						// 先頭の区切り文字を無視する
						++ next
					}
					
					Character.isDigit(c) -> {
						// 数字列のノード
						val start = next ++
						while(next < end && Character.isDigit(src[next])) ++ next
						val value = BigInteger(src.substring(start, next))
						node_list.add(value)
					}
					
					else -> {
						val m = reRcX.matcher(src)
						
						if(DUMP) {
							if(m.find(next)) {
								println("next=$next, matct_start=${m.start()}")
							} else {
								println("next=$next, not match.")
							}
						}
						
						if(m.find(next) && m.start() == next) {
							// RCノード
							next = m.end()
							val numStr = m.groupEx(1)
							val num = if(numStr?.isNotEmpty() == true) {
								numStr.toInt()
							} else {
								0
							}
							node_list.add(RC(num))
						} else {
							// 区切り文字と数字以外の文字が並ぶノード
							val start = next ++
							while(next < end) {
								c = src[next]
								if(isDelimiter(c)) break
								if(Character.isDigit(c)) break
								++ next
							}
							val value = src.substring(start, next)
							node_list.add(value)
							
						}
						
					}
				}
			}
		}
	}
	
	companion object : Comparator<VersionString> {
		
		private const val DUMP = false
		
		private fun isDelimiter(c : Char) : Boolean {
			return c == '.' || c == ' '
		}
		
		private val reRcX = "rc(\\d*)".asciiPattern()
		
		private fun checkTail(b : Any) : Int {
			// 1.0 < 1.0.n  => -1
			// 1.0 < 1.0xxx => -1
			// 1.0 > 1.0rc1  => 1
			return if(b is RC) 1 else - 1
		}
		
		private fun checkBigInteger(a : BigInteger, b : Any) : Int {
			if(b is BigInteger) return a.compareTo(b)
			// 数字 > 数字以外
			// 1.5.n > 1.5xxx
			// 1.5.n > 1.5rc1
			return 1
		}
		
		private fun checkRc(a : RC, b : Any) : Int {
			if(b is RC) return a.compareTo(b)
			// RC < string
			// 1.5rc < 1.5xxx
			return - 1
		}
		
		// return -1 if a<b , return 1 if a>b , return 0 if a==b
		override fun compare(a : VersionString, b : VersionString) : Int {
			var idx = 0
			loop@ while(true) {
				val ao = if(idx >= a.node_list.size) null else a.node_list[idx]
				val bo = if(idx >= b.node_list.size) null else b.node_list[idx]
				if(DUMP) println("a=$ao,b=$bo")
				
				val i = when {
					ao == null -> {
						if(bo == null) return 0
						checkTail(bo)
					}
					
					bo == null -> - checkTail(ao)
					ao is BigInteger -> checkBigInteger(ao, bo)
					bo is BigInteger -> - checkBigInteger(bo, ao)
					ao is RC -> checkRc(ao, bo)
					bo is RC -> - checkRc(bo, ao)
					else -> a.toString().compareTo(b.toString())
				}
				if(i == 0) {
					++ idx
					continue@loop
				}
				return i
			}
		}
	}
}