//

//  UIColorExtension.swift

//  HEXColor

//

//  Created by R0CKSTAR on 6/13/14.

//  Copyright (c) 2014 P.D.Q. All rights reserved.

//

import UIKit

/**

 MissingHashMarkAsPrefix:   "Invalid RGB string, missing '#' as prefix"

 UnableToScanHexValue:      "Scan hex error"

 MismatchedHexStringLength: "Invalid RGB string, number of characters after '#' should be either 3, 4, 6 or 8"

 */

public enum UIColorInputError : ErrorType {

    case MissingHashMarkAsPrefix,

    UnableToScanHexValue,

    MismatchedHexStringLength

}

extension UIColor {

    /**

     The shorthand three-digit hexadecimal representation of color.

     #RGB defines to the color #RRGGBB.

     - parameter hex3: Three-digit hexadecimal value.

     - parameter alpha: 0.0 - 1.0. The default is 1.0.

     */

    public convenience init(hex3: UInt16, alpha: CGFloat = 1) {

        let divisor = CGFloat(15)

        let red     = CGFloat((hex3 & 0xF00) >> 8) / divisor

        let green   = CGFloat((hex3 & 0x0F0) >> 4) / divisor

        let blue    = CGFloat( hex3 & 0x00F      ) / divisor

        self.init(red: red, green: green, blue: blue, alpha: alpha)

    }

    /**

     The shorthand four-digit hexadecimal representation of color with alpha.

     #RGBA defines to the color #RRGGBBAA.

     - parameter hex4: Four-digit hexadecimal value.

     */

    public convenience init(hex4: UInt16) {

        let divisor = CGFloat(15)

        let red     = CGFloat((hex4 & 0xF000) >> 12) / divisor

        let green   = CGFloat((hex4 & 0x0F00) >>  8) / divisor

        let blue    = CGFloat((hex4 & 0x00F0) >>  4) / divisor

        let alpha   = CGFloat( hex4 & 0x000F       ) / divisor

        self.init(red: red, green: green, blue: blue, alpha: alpha)

    }

    /**

     The six-digit hexadecimal representation of color of the form #RRGGBB.

     - parameter hex6: Six-digit hexadecimal value.

     */

    public convenience init(hex6: UInt32, alpha: CGFloat = 1) {

        let divisor = CGFloat(255)

        let red     = CGFloat((hex6 & 0xFF0000) >> 16) / divisor

        let green   = CGFloat((hex6 & 0x00FF00) >>  8) / divisor

        let blue    = CGFloat( hex6 & 0x0000FF       ) / divisor

        self.init(red: red, green: green, blue: blue, alpha: alpha)

    }

    /**

     The six-digit hexadecimal representation of color with alpha of the form #RRGGBBAA.

     - parameter hex8: Eight-digit hexadecimal value.

     */

    public convenience init(hex8: UInt32) {

        let divisor = CGFloat(255)

        let red     = CGFloat((hex8 & 0xFF000000) >> 24) / divisor

        let green   = CGFloat((hex8 & 0x00FF0000) >> 16) / divisor

        let blue    = CGFloat((hex8 & 0x0000FF00) >>  8) / divisor

        let alpha   = CGFloat( hex8 & 0x000000FF       ) / divisor

        self.init(red: red, green: green, blue: blue, alpha: alpha)

    }

    /**

     The rgba string representation of color with alpha of the form #RRGGBBAA/#RRGGBB, throws error.

     - parameter rgba: String value.

     */

    public convenience init(rgba_throws rgba: String) throws {

        guard rgba.hasPrefix("#") else {

            throw UIColorInputError.MissingHashMarkAsPrefix

        }

        guard let hexString: String = rgba.substringFromIndex(rgba.startIndex.advancedBy(1)),

            var   hexValue:  UInt32 = 0

            where NSScanner(string: hexString).scanHexInt(&hexValue) else {

                throw UIColorInputError.UnableToScanHexValue

        }

        guard hexString.characters.count  == 3

            || hexString.characters.count == 4

            || hexString.characters.count == 6

            || hexString.characters.count == 8 else {

                throw UIColorInputError.MismatchedHexStringLength

        }

        switch (hexString.characters.count) {

        case 3:

            self.init(hex3: UInt16(hexValue))

        case 4:

            self.init(hex4: UInt16(hexValue))

        case 6:

            self.init(hex6: hexValue)

        default:

            self.init(hex8: hexValue)

        }

    }

    /**

     The rgba string representation of color with alpha of the form #RRGGBBAA/#RRGGBB, fails to default color.

     - parameter rgba: String value.

     */

    public convenience init(rgba: String, defaultColor: UIColor = UIColor.clearColor()) {

        guard let color = try? UIColor(rgba_throws: rgba) else {

            self.init(CGColor: defaultColor.CGColor)

            return

        }

        self.init(CGColor: color.CGColor)

    }

    /**

     Hex string of a UIColor instance.

     - parameter rgba: Whether the alpha should be included.

     */

    public func hexString(includeAlpha: Bool) -> String {

        var r: CGFloat = 0

        var g: CGFloat = 0

        var b: CGFloat = 0

        var a: CGFloat = 0

        self.getRed(&r, green: &g, blue: &b, alpha: &a)

        if (includeAlpha) {

            return String(format: "#%02X%02X%02X%02X", Int(r * 255), Int(g * 255), Int(b * 255), Int(a * 255))

        } else {

            return String(format: "#%02X%02X%02X", Int(r * 255), Int(g * 255), Int(b * 255))

        }

    }

    public override var description: String {

        return self.hexString(true)

    }

    public override var debugDescription: String {

        return self.hexString(true)

    }

}