//

// FileGroup.swift

// iina

//

// Created by lhc on 20/5/2017.

// Copyright © 2017 lhc. All rights reserved.

//

import Foundation

fileprivate let subsystem = Logger.makeSubsystem("fgroup")

class FileInfo: Hashable {

var url: URL

var path: String

var filename: String

var ext: String

var nameInSeries: String?

var characters: [Character]

var dist: [FileInfo: UInt] = [:]

var minDist: [FileInfo] = []

var relatedSubs: [FileInfo] = []

var priorityStringOccurrences = 0

var isMatched = false

var prefix: String { // prefix detected by FileGroup

didSet {

if prefix.count < self.characters.count {

suffix = String(filename[filename.index(filename.startIndex, offsetBy: prefix.count)...])

getNameInSeries()

} else {

prefix = ""

suffix = self.filename

}

}

}

var suffix: String // filename - prefix

init(_ url: URL) {

self.url = url

self.path = url.path

self.ext = url.pathExtension

self.filename = url.deletingPathExtension().lastPathComponent

self.characters = [Character](self.filename)

self.prefix = ""

self.suffix = self.filename

}

private func getNameInSeries() {

// e.g. "abc_" "ch01_xxx" -> "ch01"

var firstDigit = false

let name = suffix.unicodeScalars.prefix {

if CharacterSet.decimalDigits.contains($0) {

if !firstDigit {

firstDigit = true

}

} else {

if firstDigit {

return false

}

}

return true

}

self.nameInSeries = String(name)

}

func hash(into hasher: inout Hasher) {

hasher.combine(path)

}

static func == (lhs: FileInfo, rhs: FileInfo) -> Bool {

return lhs.path == rhs.path

}

}

class FileGroup {

var prefix: String

var contents: [FileInfo]

var groups: [FileGroup]

private let chineseNumbers: [Character] = ["零", "一", "二", "三", "四", "五", "六", "七", "八", "九", "十"]

static func group(files: [FileInfo]) -> FileGroup {

Logger.log("Start grouping \(files.count) files", subsystem: subsystem)

let group = FileGroup(prefix: "", contents: files)

group.tryGroupFiles()

return group

}

init(prefix: String, contents: [FileInfo] = []) {

self.prefix = prefix

self.contents = contents

self.groups = []

}

private func tryGroupFiles() {

Logger.log("Try group files, prefix=\(prefix), count=\(contents.count)", level: .verbose, subsystem: subsystem)

guard contents.count >= 3 else {

Logger.log("Contents count < 3, skipped", level: .verbose, subsystem: subsystem)

return

}

var tempGroup: [String: [FileInfo]] = [:]

var currChars: [(Character, String)] = []

var i = prefix.count

while tempGroup.count < 2 {

var lastPrefix = prefix

var anyProcessed = false

for finfo in contents {

// if reached string end

if i >= finfo.characters.count {

tempGroup[prefix, default: []].append(finfo)

currChars.append(("/", prefix))

continue

}

let c = finfo.characters[i]

var p = prefix

p.append(c)

lastPrefix = p

if tempGroup[p] == nil {

tempGroup[p] = []

currChars.append((c, p))

}

tempGroup[p]!.append(finfo)

anyProcessed = true

}

// if all items have the same prefix

if tempGroup.count == 1 {

prefix = lastPrefix

tempGroup.removeAll()

currChars.removeAll()

}

i += 1

// if all items have the same name

if !anyProcessed {

break

}

}

let maxSubGroupCount = tempGroup.reduce(0, { max($0, $1.value.count) })

if stopGrouping(currChars) || maxSubGroupCount < 3 {

Logger.log("Stop grouping, maxSubGroup=\(maxSubGroupCount)", level: .verbose, subsystem: subsystem)

contents.forEach { $0.prefix = self.prefix }

} else {

Logger.log("Continue grouping, groups=\(tempGroup.count), chars=\(currChars)", level: .verbose, subsystem: subsystem)

groups = tempGroup.map { FileGroup(prefix: $0.0, contents: $0.1) }

// continue

for g in groups {

g.tryGroupFiles()

}

}

}

func flatten() -> [String: [FileInfo]] {

var result: [String: [FileInfo]] = [:]

func search(_ group: FileGroup) {

if group.groups.count > 0 {

for g in group.groups {

search(g)

}

} else {

result[group.prefix] = group.contents

}

}

search(self)

return result

}

private func stopGrouping(_ chars: [(Character, String)]) -> Bool {

var chineseNumberCount = 0

for (c, _) in chars {

if c >= "0" && c <= "9" { return true }

// chinese characters

if chineseNumbers.contains(c) { chineseNumberCount += 1 }

if chineseNumberCount >= 3 { return true }

}

return false

}

}