//
//  LabelAttributeModel.swift
//  VDS
//
//  Created by Matt Bruce on 8/3/22.
//

import Foundation
import UIKit

public protocol LabelAttributeModel: AnyEquatable, Withable, Equatable, Identifiable where ID == UUID {
    /// Position of the starting point for this LabelAttribute.
    var location: Int { get set }
    
    /// Length from the location.
    var length: Int { get set }
    
    /// Applies the attribute to the attributedString that is given.
    /// - Parameter attributedString: AttributedString that the attributed is applied.
    func setAttribute(on attributedString: NSMutableAttributedString)
}

extension LabelAttributeModel {
    /// Range for this AttributeModel
    public var range: NSRange {
        NSRange(location: location, length: length)
    }
    
    public static func == (lhs: any LabelAttributeModel, rhs: any LabelAttributeModel) -> Bool {
        lhs.isEqual(rhs)
    }
    
    public func isValidRange(on attributedString: NSMutableAttributedString) -> Bool {
        attributedString.isValid(range: range)
    }
}

public extension String {
    func isValid(range: NSRange) -> Bool {
        range.location >= 0 && range.length > 0 && range.location + range.length <= count
    }
}

public extension NSAttributedString {
    func isValid(range: NSRange) -> Bool {
        range.location >= 0 && range.length > 0 && range.location + range.length <= length
    }
    
    func createAttributeModels() -> [(any LabelAttributeModel)] {
        var attributes: [any VDS.LabelAttributeModel] = []
        enumerateAttributes(in: NSMakeRange(0, length)) { attributeMap, range, stop in
            attributeMap.forEach { (key: NSAttributedString.Key, value: Any) in
                if let attribute = NSAttributedString.createAttributeModelFor(key: key, range: range, value: value) {
                    attributes.append(attribute)
                }
            }
        }
        return attributes
    }
    
    static func createAttributeModelFor(key: NSAttributedString.Key, range: NSRange, value: Any) -> (any LabelAttributeModel)? {
        guard let value = value as? AnyHashable else { return nil }
        
        guard let font = value as? UIFont, let style = TextStyle.style(for: font.fontName, size: font.pointSize), key == .font
        else {
            return AnyAttribute(location: range.location, length: range.length, key: key, value: value)
        }
        return TextStyleLabelAttribute(location: range.location, length: range.length, textStyle: style)
    }
}

extension NSMutableAttributedString {
    public func apply(attribute: any LabelAttributeModel) {
        guard isValid(range: attribute.range) else { return }
        attribute.setAttribute(on: self)
    }
    
    public func apply(attributes: [any LabelAttributeModel]) {
        attributes.forEach { apply(attribute: $0) }
    }
}