/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

import Foundation
import SnapKit

private struct SearchInputViewUX {

    static let horizontalSpacing: CGFloat = 16
    static let titleFont: UIFont = UIFont.systemFont(ofSize: 16)
    static let titleColor: UIColor = UIColor.lightGray
    static let inputColor: UIColor = UIConstants.HighlightBlue
    static let borderColor: UIColor = UIConstants.SeparatorColor
    static let borderLineWidth: CGFloat = 0.5
    static let closeButtonSize: CGFloat = 36
}

@objc protocol SearchInputViewDelegate: class {

    func searchInputView(_ searchView: SearchInputView, didChangeTextTo text: String)

    func searchInputViewBeganEditing(_ searchView: SearchInputView)

    func searchInputViewFinishedEditing(_ searchView: SearchInputView)
}

class SearchInputView: UIView {

    weak var delegate: SearchInputViewDelegate?

    var showBottomBorder: Bool = true {
        didSet {
            bottomBorder.isHidden = !showBottomBorder
        }
    }

    lazy var inputField: UITextField = {
        let textField = UITextField()
        textField.delegate = self
        textField.textColor = SearchInputViewUX.inputColor
        textField.tintColor = SearchInputViewUX.inputColor
        textField.addTarget(self, action: #selector(SearchInputView.inputTextDidChange(_:)), for: .editingChanged)
        textField.accessibilityLabel = NSLocalizedString("Search Input Field", tableName: "LoginManager", comment: "Accessibility label for the search input field in the Logins list")
        textField.autocorrectionType = .no
        textField.autocapitalizationType = .none
        return textField
    }()

    lazy var titleLabel: UILabel = {
        let label = UILabel()
        label.text = NSLocalizedString("Search", tableName: "LoginManager", comment: "Title for the search field at the top of the Logins list screen")
        label.font = SearchInputViewUX.titleFont
        label.textColor = SearchInputViewUX.titleColor
        return label
    }()

    lazy var searchIcon: UIImageView = {
        return UIImageView(image: UIImage(named: "quickSearch"))
    }()

    fileprivate lazy var closeButton: UIButton = {
        let button = UIButton()
        button.addTarget(self, action: #selector(SearchInputView.tappedClose), for: .touchUpInside)
        button.setImage(UIImage(named: "clear"), for: UIControlState())
        button.accessibilityLabel = NSLocalizedString("Clear Search", tableName: "LoginManager",
            comment: "Accessibility message e.g. spoken by VoiceOver after the user taps the close button in the search field to clear the search and exit search mode")
        return button
    }()

    fileprivate var centerContainer = UIView()

    fileprivate lazy var bottomBorder: UIView = {
        let border = UIView()
        border.backgroundColor = SearchInputViewUX.borderColor
        return border
    }()

    fileprivate lazy var overlay: UIView = {
        let view = UIView()
        view.backgroundColor = UIColor.white
        view.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(SearchInputView.tappedSearch)))

        view.isAccessibilityElement = true
        view.accessibilityLabel =  NSLocalizedString("Enter Search Mode", tableName: "LoginManager", comment: "Accessibility label for entering search mode for logins")
        return view
    }()

    fileprivate(set) var isEditing = false {
        didSet {
            if isEditing {
                overlay.isHidden = true
                inputField.isHidden = false
                inputField.accessibilityElementsHidden = false
                closeButton.isHidden = false
                closeButton.accessibilityElementsHidden = false
            } else {
                overlay.isHidden = false
                inputField.isHidden = true
                inputField.accessibilityElementsHidden = true
                closeButton.isHidden = true
                closeButton.accessibilityElementsHidden = true
            }
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)

        backgroundColor = UIColor.white
        isUserInteractionEnabled = true

        addSubview(inputField)
        addSubview(closeButton)

        centerContainer.addSubview(searchIcon)
        centerContainer.addSubview(titleLabel)
        overlay.addSubview(centerContainer)
        addSubview(overlay)
        addSubview(bottomBorder)

        setupConstraints()

        setEditing(false)
    }

    fileprivate func setupConstraints() {
        centerContainer.snp.makeConstraints { make in
            make.center.equalTo(overlay)
        }

        overlay.snp.makeConstraints { make in
            make.edges.equalTo(self)
        }

        searchIcon.snp.makeConstraints { make in
            make.right.equalTo(titleLabel.snp.left).offset(-SearchInputViewUX.horizontalSpacing)
            make.centerY.equalTo(centerContainer)
        }

        titleLabel.snp.makeConstraints { make in
            make.center.equalTo(centerContainer)
        }

        inputField.snp.makeConstraints { make in
            make.left.equalTo(self).offset(SearchInputViewUX.horizontalSpacing)
            make.centerY.equalTo(self)
            make.right.equalTo(closeButton.snp.left).offset(-SearchInputViewUX.horizontalSpacing)
        }

        closeButton.snp.makeConstraints { make in
            make.right.equalTo(self).offset(-SearchInputViewUX.horizontalSpacing)
            make.centerY.equalTo(self)
            make.size.equalTo(SearchInputViewUX.closeButtonSize)
        }

        bottomBorder.snp.makeConstraints { make in
            make.left.right.bottom.equalTo(self)
            make.height.equalTo(SearchInputViewUX.borderLineWidth)
        }
    }

    // didSet callbacks don't trigger when a property is being set in the init() call 
    // but calling a method that does works fine.
    fileprivate func setEditing(_ editing: Bool) {
        isEditing = editing
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

// MARK: - Selectors
extension SearchInputView {

    func tappedSearch() {
        isEditing = true
        inputField.becomeFirstResponder()
        delegate?.searchInputViewBeganEditing(self)
    }

    func tappedClose() {
        isEditing = false
        delegate?.searchInputViewFinishedEditing(self)
        inputField.text = nil
        inputField.resignFirstResponder()
    }

    func inputTextDidChange(_ textField: UITextField) {
        delegate?.searchInputView(self, didChangeTextTo: textField.text ?? "")
    }
}

// MARK: - UITextFieldDelegate
extension SearchInputView: UITextFieldDelegate {

    func textFieldDidEndEditing(_ textField: UITextField) {
        // If there is no text, go back to showing the title view
        if (textField.text?.characters.count ?? 0) == 0 {
            isEditing = false
            delegate?.searchInputViewFinishedEditing(self)
        }
    }
}