//
//  VDSLabel.swift
//  VDS
//
//  Created by Matt Bruce on 7/28/22.
//

import Foundation
import UIKit
import VDSColorTokens
import Combine

open class Label: UILabel, ModelHandlerable, Initable {
    
    @Published public var model: LabelModel = DefaultLabelModel()
    private var cancellable: AnyCancellable?

    @Proxy(\.model.fontSize)
    public var fontSize: VDSFontSize
    
    @Proxy(\.model.textPosition)
    public var textPosition: VDSTextPosition
    
    @Proxy(\.model.fontWeight)
    public var fontWeight: VDSFontWeight
    
    @Proxy(\.model.fontCategory)
    public var fontCategory: VDSFontCategory
    
    @Proxy(\.model.surface)
    public var surface: Surface

    //Initializers
    required public convenience init() {
        self.init(frame: .zero)
    }
    
    public required convenience init(with model: LabelModel) {
        self.init()
        self.model = model
        set(with: model)
    }
    
    public override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }
    
    required public init?(coder: NSCoder) {
        super.init(coder: coder)
        setup()
    }
    
    private func setup() {
        cancellable = $model.debounce(for: .seconds(Constants.ModelStateDebounce), scheduler: RunLoop.main).sink { [weak self] viewModel in
            self?.onStateChange(viewModel: viewModel)
        }
    }
    
    private func getTextColor(for disabled: Bool, surface: Surface) -> UIColor {
        if disabled {
            if surface == .light {
                return VDSColor.elementsSecondaryOnlight
            } else {
                return VDSColor.elementsSecondaryOndark
            }
        } else {
            if surface == .light {
                return VDSColor.elementsPrimaryOnlight
            } else {
                return VDSColor.elementsPrimaryOndark
            }
        }
    }
    
    //functions
    private func onStateChange(viewModel: LabelModel) {
        text = viewModel.text
        textAlignment = viewModel.textPosition.textAlignment
        textColor = getTextColor(for: viewModel.disabled, surface: viewModel.surface)
       
        guard let vdsFont = try? VDSFontStyle.font(for: viewModel.fontCategory, fontWeight: viewModel.fontWeight, fontSize: viewModel.fontSize) else {
            font = VDSFontStyle.RegularBodyLarge.font
            return
        }
        font = vdsFont
    }
    
    //Modelable
    public func set(with model: LabelModel) {
        self.model = model
    }
}