//
//  EntryField.swift
//  VDS
//
//  Created by Matt Bruce on 10/3/22.
//

import Foundation
import UIKit
import VDSTokens
import Combine

/// Base Class used to build out a Input controls.
@objc(VDSEntryField)
open class EntryFieldBase: Control, Changeable, FormFieldInternalValidatable {
    
    //--------------------------------------------------
    // MARK: - Initializers
    //--------------------------------------------------
    required public init() {
        super.init(frame: .zero)
    }
    
    public override init(frame: CGRect) {
        super.init(frame: .zero)
    }
    
    public required init?(coder: NSCoder) {
        super.init(coder: coder)
    }

    //--------------------------------------------------
    // MARK: - Enums
    //--------------------------------------------------
    /// Enum used to describe the position of the helper text.
    public enum HelperTextPlacement: String, CaseIterable {
        case bottom, right
    }

    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    internal var primaryStackView: UIStackView = {
        return UIStackView().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
            $0.axis = .vertical
            $0.distribution = .fill
            $0.alignment = .leading
        }
    }()
    
    internal let secondaryStackView = UIStackView().with {
        $0.translatesAutoresizingMaskIntoConstraints = false
        $0.axis = .vertical
        $0.distribution = .fill
    }
    
    /// This is the view that will be wrapped with the border for userInteraction.
    internal var containerView: UIView = {
        return UIView().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
        }
    }()
    
    /// This is a horizontal Stack View that is placed inside the containterView (bordered view)
    /// The first arrangedView will be the view from getFieldContainer()
    /// The second view is the statusIcon.
    internal var fieldStackView: UIStackView = {
        return UIStackView().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
            $0.axis = .horizontal
            $0.distribution = .fill
            $0.alignment = .top
        }
    }()
    
    /// This is a vertical stack used for the errorLabel and helperLabel.
    internal var bottomContainerStackView: UIStackView = {
        return UIStackView().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
            $0.axis = .vertical
            $0.distribution = .fill
            $0.spacing = VDSLayout.space2X
        }
    }()
    
    open var rules = [AnyRule<String>]()

    //--------------------------------------------------
    // MARK: - Configuration Properties
    //--------------------------------------------------
    // Sizes are from InVision design specs.
    internal var containerSize: CGSize { CGSize(width: 45, height: 44) }
    
    internal let primaryColorConfiguration =  ViewColorConfiguration().with {
        $0.setSurfaceColors(VDSColor.interactiveDisabledOnlight, VDSColor.interactiveDisabledOndark, forDisabled: true)
        $0.setSurfaceColors(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOndark, forDisabled: false)
    }
    
    internal let secondaryColorConfiguration = ViewColorConfiguration().with {
        $0.setSurfaceColors(VDSColor.interactiveDisabledOnlight, VDSColor.interactiveDisabledOndark, forDisabled: true)
        $0.setSurfaceColors(VDSColor.elementsSecondaryOnlight, VDSColor.elementsSecondaryOndark, forDisabled: false)
    }

    internal var backgroundColorConfiguration = ControlColorConfiguration().with {
        $0.setSurfaceColors(VDSFormControlsColor.backgroundOnlight, VDSFormControlsColor.backgroundOndark, forState: .normal)
        $0.setSurfaceColors(VDSFormControlsColor.backgroundOnlight, VDSFormControlsColor.backgroundOndark, forState: .disabled)
        $0.setSurfaceColors(VDSColor.feedbackErrorBackgroundOnlight, VDSColor.feedbackErrorBackgroundOndark, forState: .error)
        $0.setSurfaceColors(VDSColor.feedbackErrorBackgroundOnlight, VDSColor.feedbackErrorBackgroundOndark, forState: [.error, .focused])
    }

    internal var borderColorConfiguration = ControlColorConfiguration().with {
        $0.setSurfaceColors(VDSFormControlsColor.borderOnlight, VDSFormControlsColor.borderOndark, forState: .normal)
        $0.setSurfaceColors(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOnlight, forState: .focused)
        $0.setSurfaceColors(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOnlight, forState: [.focused, .error])
        $0.setSurfaceColors(VDSColor.interactiveDisabledOnlight, VDSColor.interactiveDisabledOndark, forState: .disabled)
        $0.setSurfaceColors(VDSColor.feedbackErrorOnlight, VDSColor.feedbackErrorOndark, forState: .error)
        $0.setSurfaceColors(VDSColor.interactiveDisabledOnlight, VDSColor.interactiveDisabledOndark, forState: [.disabled,.error])
    }
    
    internal let iconColorConfiguration =  ControlColorConfiguration().with {
        $0.setSurfaceColors(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOndark, forState: .normal)
        $0.setSurfaceColors(VDSColor.interactiveDisabledOnlight, VDSColor.interactiveDisabledOndark, forState: .disabled)
        $0.setSurfaceColors(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOndark, forState: .error)
    }

    internal var readOnlyBorderColorConfiguration = ControlColorConfiguration().with {
        $0.setSurfaceColors(VDSFormControlsColor.borderReadonlyOnlight, VDSFormControlsColor.borderReadonlyOndark, forState: .normal)
    }
    
    //--------------------------------------------------
    // MARK: - Public Properties
    //--------------------------------------------------
    open var onChangeSubscriber: AnyCancellable? 

    open var titleLabel = Label().with {
        $0.setContentCompressionResistancePriority(.required, for: .vertical)
        $0.textStyle = .bodySmall
    }
    
    open var errorLabel = Label().with {
        $0.setContentCompressionResistancePriority(.required, for: .vertical)
        $0.textStyle = .bodySmall
        $0.accessibilityValue = "error"
    }
    
    open var helperLabel = Label().with {
        $0.setContentCompressionResistancePriority(.required, for: .vertical)
        $0.textStyle = .bodySmall
    }
    
    open var statusIcon: Icon = Icon().with {
        $0.size = .medium
    }
        
    open var labelText: String? { didSet { setNeedsUpdate() } }
    
    open var helperText: String? { didSet { setNeedsUpdate() } }
    
    /// Whether not to show the error.
    open var showError: Bool = false { didSet { setNeedsUpdate() } }
    
    /// FormFieldValidator
    open var validator: (any FormFieldValidatorable)?

    /// Override UIControl state to add the .error state if showError is true.
    open override var state: UIControl.State {
        get {
            var state = super.state
            if showError || hasInternalError {
                state.insert(.error)
            }
            return state
        }
    }
        
    open var errorText: String? { didSet { setNeedsUpdate() } }
            
    open var tooltipModel: Tooltip.TooltipModel? { didSet { setNeedsUpdate() } }
        
    open var transparentBackground: Bool = false { didSet { setNeedsUpdate() } }
    
    open var width: CGFloat? { didSet { setNeedsUpdate() } }
        
    open var inputId: String? { didSet { setNeedsUpdate() } }
        
    /// The text of this textField.
    open var value: String? {
        get { fatalError("must be read from subclass")}
    }
    
    open var defaultValue: AnyHashable? { didSet { setNeedsUpdate() } }
    
    open var isRequired: Bool = false { didSet { setNeedsUpdate() } }
    
    open var isReadOnly: Bool = false { didSet { setNeedsUpdate() } }
    
    //--------------------------------------------------
    // MARK: - Constraints
    //--------------------------------------------------
    internal var heightConstraint: NSLayoutConstraint?
    internal var widthConstraint: NSLayoutConstraint?
    
    //--------------------------------------------------
    // MARK: - Overrides
    //--------------------------------------------------
    /// Called once when a view is initialized and is used to Setup additional UI or other constants and configurations.
    open override func setup() {
        super.setup()
                
        isAccessibilityElement = false
        addSubview(primaryStackView)
        
        //create the wrapping view
        heightConstraint = containerView.heightGreaterThanEqualTo(constant: containerSize.height)
        widthConstraint = containerView.width(constant: 0)
        
        secondaryStackView.addArrangedSubview(containerView)
        secondaryStackView.setCustomSpacing(8, after: containerView)

        //add ContainerStackView
        //this is the horizontal stack that contains
        //the left, InputContainer, Icons, Buttons
        containerView.addSubview(fieldStackView)
        fieldStackView.pinToSuperView(.uniform(VDSLayout.space3X))
    
        let fieldContainerView = getFieldContainer()
        fieldContainerView.translatesAutoresizingMaskIntoConstraints = false
        
        //add the view to add input fields
        fieldStackView.addArrangedSubview(fieldContainerView)
        fieldStackView.addArrangedSubview(statusIcon)
        fieldStackView.setCustomSpacing(VDSLayout.space3X, after: fieldContainerView)

        //get the container this is what show helper text, error text
        //can include other for character count, max length
        let bottomContainer = getBottomContainer()

        //this is the vertical stack that contains error text, helper text
        bottomContainerStackView.addArrangedSubview(errorLabel)
        bottomContainerStackView.addArrangedSubview(helperLabel)
        
        primaryStackView.addArrangedSubview(titleLabel)
        primaryStackView.addArrangedSubview(secondaryStackView)
        secondaryStackView.addArrangedSubview(bottomContainer)

        primaryStackView.setCustomSpacing(4, after: titleLabel)

        primaryStackView
            .pinTop()
            .pinLeading()
            .pinTrailing(0, .defaultHigh)
            .pinBottom(0, .defaultHigh)

        titleLabel.textColorConfiguration = primaryColorConfiguration.eraseToAnyColorable()
        errorLabel.textColorConfiguration = primaryColorConfiguration.eraseToAnyColorable()
        helperLabel.textColorConfiguration = secondaryColorConfiguration.eraseToAnyColorable()
    }
            
    /// Resets to default settings.
    open override func reset() {
        super.reset()
        titleLabel.reset()
        errorLabel.reset()
        helperLabel.reset()
        
        titleLabel.textStyle = .bodySmall
        errorLabel.textStyle = .bodySmall
        helperLabel.textStyle = .bodySmall

        labelText = nil
        helperText = nil
        showError = false
        errorText = nil
        tooltipModel = nil
        transparentBackground = false
        width = nil
        inputId = nil
        defaultValue = nil
        isRequired = false
        isReadOnly = false
        onChange = nil 
    }
    
    /// Used to make changes to the View based off a change events or from local properties.
    open override func updateView() {
        super.updateView()
        updateContainerView()
        updateTitleLabel()
        updateErrorLabel()
        updateHelperLabel()
    }
    
    open func validate(){
        updateRules()
        validator = FormFieldValidator<EntryFieldBase>(field: self, rules: rules)
        validator?.validate()
        setNeedsUpdate()
    }
    
    //--------------------------------------------------
    // MARK: - Private Methods
    //--------------------------------------------------
    private func updateContainerView()  {
        containerView.backgroundColor = backgroundColorConfiguration.getColor(self)
        containerView.layer.borderColor = isReadOnly ? readOnlyBorderColorConfiguration.getColor(self).cgColor : borderColorConfiguration.getColor(self).cgColor
        containerView.layer.borderWidth = VDSFormControls.borderWidth
        containerView.layer.cornerRadius = VDSFormControls.borderRadius
    }
        
    //--------------------------------------------------
    // MARK: - Public Methods
    //--------------------------------------------------
    /// Container for the area in which the user interacts.
    open func getFieldContainer() -> UIView {
        fatalError("Subclass must return the view that contains the field/view the user will interact with.")
    }
   
    /// Container for the area in which helper or error text presents.
    open func getBottomContainer() -> UIView {
        return bottomContainerStackView
    }
    
    internal func updateRules() {
        rules.removeAll()
        if self.isRequired {
            let rule = RequiredRule()
            if let errorText, !errorText.isEmpty {
                rule.errorMessage = errorText
            } else if let labelText{
                rule.errorMessage = "You must enter a \(labelText)"
            } else {
                rule.errorMessage = "You must enter a value"
            }
            rules.append(.init(rule))
        }
    }
    
    open func updateTitleLabel() {
               
        //update the local vars for the label since we no
        //long have a model
        var attributes: [any LabelAttributeModel] = []
        var updatedLabelText = labelText
        
        //dealing with the "Optional" addition to the text
        if let oldText = updatedLabelText, !isRequired, !oldText.hasSuffix("Optional")  {
            if isEnabled {
                let optionColorAttr = ColorLabelAttribute(location: oldText.count + 2,
                                                          length: 8,
                                                          color: VDSColor.elementsSecondaryOnlight)
                
                attributes.append(optionColorAttr)
            }
            updatedLabelText = "\(oldText)  Optional"
        }
        
        if let tooltipModel {
            attributes.append(TooltipLabelAttribute(surface: surface, model: tooltipModel, presenter: self))
        }

        //set the titleLabel
        titleLabel.text = updatedLabelText
        titleLabel.attributes = attributes
        titleLabel.surface = surface
        titleLabel.isEnabled = isEnabled
    }
    
    open func updateErrorLabel(){
        if showError, let errorText {
            errorLabel.text = errorText
            errorLabel.surface = surface
            errorLabel.isEnabled = isEnabled
            errorLabel.isHidden = false
            statusIcon.name = .error
            statusIcon.surface = surface
            statusIcon.isHidden = !isEnabled || state.contains(.focused)
        } else if hasInternalError, let internalErrorText {
            errorLabel.text = internalErrorText
            errorLabel.surface = surface
            errorLabel.isEnabled = isEnabled
            errorLabel.isHidden = false
            statusIcon.name = .error
            statusIcon.surface = surface
            statusIcon.isHidden = !isEnabled || state.contains(.focused)
        } else {
            statusIcon.isHidden = true
            errorLabel.isHidden = true
        }
        statusIcon.color = iconColorConfiguration.getColor(self)
    }
    
    open func updateHelperLabel(){
        //set the helper label position
        if let helperText {
            helperLabel.text = helperText
            helperLabel.surface = surface
            helperLabel.isEnabled = isEnabled
            helperLabel.isHidden = false
        } else {
            helperLabel.isHidden = true
        }
    }
}