/*
 MIT License
 
 Copyright (c) 2017-2019 MessageKit
 
 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.
 */

import Foundation

public class Lorem {
    private static let wordList = [
        "alias", "consequatur", "aut", "perferendis", "sit", "voluptatem",
        "accusantium", "doloremque", "aperiam", "eaque", "ipsa", "quae", "ab",
        "illo", "inventore", "veritatis", "et", "quasi", "architecto",
        "beatae", "vitae", "dicta", "sunt", "explicabo", "aspernatur", "aut",
        "odit", "aut", "fugit", "sed", "quia", "consequuntur", "magni",
        "dolores", "eos", "qui", "ratione", "voluptatem", "sequi", "nesciunt",
        "neque", "dolorem", "ipsum", "quia", "dolor", "sit", "amet",
        "consectetur", "adipisci", "velit", "sed", "quia", "non", "numquam",
        "eius", "modi", "tempora", "incidunt", "ut", "labore", "et", "dolore",
        "magnam", "aliquam", "quaerat", "voluptatem", "ut", "enim", "ad",
        "minima", "veniam", "quis", "nostrum", "exercitationem", "ullam",
        "corporis", "nemo", "enim", "ipsam", "voluptatem", "quia", "voluptas",
        "sit", "suscipit", "laboriosam", "nisi", "ut", "aliquid", "ex", "ea",
        "commodi", "consequatur", "quis", "autem", "vel", "eum", "iure",
        "reprehenderit", "qui", "in", "ea", "voluptate", "velit", "esse",
        "quam", "nihil", "molestiae", "et", "iusto", "odio", "dignissimos",
        "ducimus", "qui", "blanditiis", "praesentium", "laudantium", "totam",
        "rem", "voluptatum", "deleniti", "atque", "corrupti", "quos",
        "dolores", "et", "quas", "molestias", "excepturi", "sint",
        "occaecati", "cupiditate", "non", "provident", "sed", "ut",
        "perspiciatis", "unde", "omnis", "iste", "natus", "error",
        "similique", "sunt", "in", "culpa", "qui", "officia", "deserunt",
        "mollitia", "animi", "id", "est", "laborum", "et", "dolorum", "fuga",
        "et", "harum", "quidem", "rerum", "facilis", "est", "et", "expedita",
        "distinctio", "nam", "libero", "tempore", "cum", "soluta", "nobis",
        "est", "eligendi", "optio", "cumque", "nihil", "impedit", "quo",
        "porro", "quisquam", "est", "qui", "minus", "id", "quod", "maxime",
        "placeat", "facere", "possimus", "omnis", "voluptas", "assumenda",
        "est", "omnis", "dolor", "repellendus", "temporibus", "autem",
        "quibusdam", "et", "aut", "consequatur", "vel", "illum", "qui",
        "dolorem", "eum", "fugiat", "quo", "voluptas", "nulla", "pariatur",
        "at", "vero", "eos", "et", "accusamus", "officiis", "debitis", "aut",
        "rerum", "necessitatibus", "saepe", "eveniet", "ut", "et",
        "voluptates", "repudiandae", "sint", "et", "molestiae", "non",
        "recusandae", "itaque", "earum", "rerum", "hic", "tenetur", "a",
        "sapiente", "delectus", "ut", "aut", "reiciendis", "voluptatibus",
        "maiores", "doloribus", "asperiores", "repellat"
    ]
    
    /**
     Return a random word.
     
     - returns: Returns a random word.
     */
    public class func word() -> String {
        return wordList.random()!
    }
    
    /**
     Return an array of `count` words.
     
     - parameter count: The number of words to return.
     
     - returns: Returns an array of `count` words.
     */
    public class func words(nbWords: Int = 3) -> [String] {
        return wordList.random(nbWords)
    }
    
    /**
     Return a string of `count` words.
     
     - parameter count: The number of words the string should contain.
     
     - returns: Returns a string of `count` words.
     */
    public class func words(nbWords: Int = 3) -> String {
        return words(nbWords: nbWords).joined(separator: " ")
    }
    
    /**
     Generate a sentence of `nbWords` words.
     - parameter nbWords:  The number of words the sentence should contain.
     - parameter variable: If `true`, the number of words will vary between
     +/- 40% of `nbWords`.
     - returns:
     */
    public class func sentence(nbWords: Int = 6, variable: Bool = true) -> String {
        if nbWords <= 0 {
            return ""
        }
        
        let result: String = words(nbWords: variable ? nbWords.randomize(variation: 40) : nbWords)
        
        return result.firstCapitalized + "."
    }
    
    /**
     Generate an array of sentences.
     - parameter nbSentences: The number of sentences to generate.
     
     - returns: Returns an array of random sentences.
     */
    public class func sentences(nbSentences: Int = 3) -> [String] {
        return (0..<nbSentences).map { _ in sentence() }
    }
    
    /**
     Generate a paragraph with `nbSentences` random sentences.
     - parameter nbSentences: The number of sentences the paragraph should
     contain.
     - parameter variable:    If `true`, the number of sentences will vary
     between +/- 40% of `nbSentences`.
     - returns: Returns a paragraph with `nbSentences` random sentences.
     */
    public class func paragraph(nbSentences: Int = 3, variable: Bool = true) -> String {
        if nbSentences <= 0 {
            return ""
        }
        
        return sentences(nbSentences: variable ? nbSentences.randomize(variation: 40) : nbSentences).joined(separator: " ")
    }
    
    /**
     Generate an array of random paragraphs.
     - parameter nbParagraphs: The number of paragraphs to generate.
     - returns: Returns an array of `nbParagraphs` paragraphs.
     */
    public class func paragraphs(nbParagraphs: Int = 3) -> [String] {
        return (0..<nbParagraphs).map { _ in paragraph() }
    }
    
    /**
     Generate a string of random paragraphs.
     - parameter nbParagraphs: The number of paragraphs to generate.
     - returns: Returns a string of random paragraphs.
     */
    public class func paragraphs(nbParagraphs: Int = 3) -> String {
        return paragraphs(nbParagraphs: nbParagraphs).joined(separator: "\n\n")
    }
    
    /**
     Generate a string of at most `maxNbChars` characters.
     - parameter maxNbChars: The maximum number of characters the string
     should contain.
     - returns: Returns a string of at most `maxNbChars` characters.
     */
    public class func text(maxNbChars: Int = 200) -> String {
        var result: [String] = []
        
        if maxNbChars < 5 {
            return ""
        } else if maxNbChars < 25 {
            while result.count == 0 {
                var size = 0
                
                while size < maxNbChars {
                    let w = (size != 0 ? " " : "") + word()
                    result.append(w)
                    size += w.count
                }
                
                _ = result.popLast()
            }
        } else if maxNbChars < 100 {
            while result.count == 0 {
                var size = 0
                
                while size < maxNbChars {
                    let s = (size != 0 ? " " : "") + sentence()
                    result.append(s)
                    size += s.count
                }
                
                _ = result.popLast()
            }
        } else {
            while result.count == 0 {
                var size = 0
                
                while size < maxNbChars {
                    let p = (size != 0 ? "\n" : "") + paragraph()
                    result.append(p)
                    size += p.count
                }
                
                _ = result.popLast()
            }
        }
        
        return result.joined(separator: "")
    }
}

extension String {
    var firstCapitalized: String {
        var string = self
        string.replaceSubrange(string.startIndex...string.startIndex, with: String(string[string.startIndex]).capitalized)
        return string
    }
}

public extension Array {
    /**
     Shuffle the array in-place using the Fisher-Yates algorithm.
     */
    mutating func shuffle() {
        if count == 0 {
            return
        }

        for i in 0..<(count - 1) {
            let j = Int(arc4random_uniform(UInt32(count - i))) + i
            if j != i {
                self.swapAt(i, j)
            }
        }
    }
    
    /**
     Return a shuffled version of the array using the Fisher-Yates
     algorithm.
     
     - returns: Returns a shuffled version of the array.
     */
    func shuffled() -> [Element] {
        var list = self
        list.shuffle()
        
        return list
    }
    
    /**
     Return a random element from the array.
     - returns: Returns a random element from the array or `nil` if the
     array is empty.
     */
    func random() -> Element? {
        return (count > 0) ? self.shuffled()[0] : nil
    }
    
    /**
     Return a random subset of `cnt` elements from the array.
     - returns: Returns a random subset of `cnt` elements from the array.
     */
    func random(_ count: Int = 1) -> [Element] {
        let result = shuffled()
        
        return (count > result.count) ? result : Array(result[0..<count])
    }
}

extension Int {
    /**
     Return a random number between `min` and `max`.
     - note: The maximum value cannot be more than `UInt32.max - 1`
     
     - parameter min: The minimum value of the random value (defaults to `0`).
     - parameter max: The maximum value of the random value (defaults to `UInt32.max - 1`)
     
     - returns: Returns a random value between `min` and `max`.
     */
    public static func random(min: Int = 0, max: Int = Int.max) -> Int {
        precondition(min <= max, "attempt to call random() with min > max")
        
        let diff   = UInt(bitPattern: max &- min)
        let result = UInt.random(min: 0, max: diff)
        
        return min + Int(bitPattern: result)
    }
    
    public func randomize(variation: Int) -> Int {
        let multiplier = Double(Int.random(min: 100 - variation, max: 100 + variation)) / 100
        let randomized = Double(self) * multiplier
        
        return Int(randomized) + 1
    }
}

private extension UInt {
    static func random(min: UInt, max: UInt) -> UInt {
        precondition(min <= max, "attempt to call random() with min > max")
        
        if min == UInt.min && max == UInt.max {
            var result: UInt = 0
            arc4random_buf(&result, MemoryLayout.size(ofValue: result))
            
            return result
        } else {
            let range         = max - min + 1
            let limit         = UInt.max - UInt.max % range
            var result: UInt = 0
            
            repeat {
                arc4random_buf(&result, MemoryLayout.size(ofValue: result))
            } while result >= limit
            
            result = result % range
            
            return min + result
        }
    }
}
