//
//  ProfileFieldsView.swift
//  Tusker
//
//  Created by Shadowfacts on 11/4/22.
//  Copyright © 2022 Shadowfacts. All rights reserved.
//

import UIKit
import Pachyderm
import SwiftUI

class ProfileFieldsView: UIView {
    
    weak var delegate: ProfileHeaderViewDelegate?
    
    private var fields = [Account.Field]()
    
    private let stack = UIStackView()
    private var fieldViews: [(EmojiLabel, ProfileFieldValueView)] = []
    private var fieldConstraints: [NSLayoutConstraint] = []
    
    private var isUsingSingleColumn: Bool = false
    private var needsSingleColumn: Bool {
        traitCollection.horizontalSizeClass == .compact && traitCollection.preferredContentSizeCategory > .extraLarge
    }
    
    override var accessibilityElements: [Any]? {
        get {
            fieldViews.flatMap { [$0.0, $0.1] }
        }
        set {}
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        commonInit()
    }
    
    private func commonInit() {
        stack.axis = .vertical
        stack.alignment = .fill
        stack.translatesAutoresizingMaskIntoConstraints = false
        addSubview(stack)
        NSLayoutConstraint.activate([
            stack.leadingAnchor.constraint(equalTo: leadingAnchor),
            stack.trailingAnchor.constraint(equalTo: trailingAnchor),
            stack.topAnchor.constraint(equalTo: topAnchor),
            stack.bottomAnchor.constraint(equalTo: bottomAnchor),
        ])
    }
    
    override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
        super.traitCollectionDidChange(previousTraitCollection)
        if isUsingSingleColumn != needsSingleColumn {
            configureFields()
        }
    }
    
    func updateUI(account: AccountMO) {
        isHidden = account.fields.isEmpty
        guard !account.fields.isEmpty,
              fields != account.fields else {
            return
        }
        fields = account.fields
        
        for (name, value) in fieldViews {
            name.removeFromSuperview()
            value.removeFromSuperview()
        }
        fieldViews = []
        
        for field in account.fields {
            let nameLabel = EmojiLabel()
            nameLabel.text = field.name
            nameLabel.font = .preferredFont(forTextStyle: .body).withTraits(.traitBold)!
            nameLabel.adjustsFontForContentSizeCategory = true
            nameLabel.numberOfLines = 0
            nameLabel.lineBreakMode = .byWordWrapping
            nameLabel.setEmojis(account.emojis, identifier: account.id)
            nameLabel.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
            
            let valueView = ProfileFieldValueView(field: field, account: account)
            valueView.navigationDelegate = delegate
            valueView.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
            
            fieldViews.append((nameLabel, valueView))
        }
        
        configureFields()
    }
    
    @objc private func configureFields() {
        guard !isHidden else {
            return
        }
        
        isUsingSingleColumn = needsSingleColumn
        
        NSLayoutConstraint.deactivate(fieldConstraints)
        fieldConstraints = []
        
        stack.arrangedSubviews.forEach { $0.removeFromSuperview() }
        
        if needsSingleColumn {
            stack.spacing = 4
            var isFirst = true
            for (name, value) in fieldViews {
                if isFirst {
                    isFirst = false
                } else {
                    let spacer = UIView()
                    // don't need any height, since there's 4pts of padding on either side
                    spacer.heightAnchor.constraint(equalToConstant: 0).isActive = true
                    stack.addArrangedSubview(spacer)
                }
                name.textAlignment = .natural
                stack.addArrangedSubview(name)
                value.setTextAlignment(.natural)
                stack.addArrangedSubview(value)
            }
        } else {
            stack.spacing = 8
            
            let dividerLayoutGuide = UILayoutGuide()
            addLayoutGuide(dividerLayoutGuide)
            fieldConstraints.append(contentsOf: [
                dividerLayoutGuide.widthAnchor.constraint(equalToConstant: 8),
            ])
            
            for (name, value) in fieldViews {
                name.textAlignment = .right
                name.translatesAutoresizingMaskIntoConstraints = false
                
                value.setTextAlignment(.left)
                value.translatesAutoresizingMaskIntoConstraints = false
                
                let fieldContainer = UIView()
                fieldContainer.addSubview(name)
                fieldContainer.addSubview(value)
                stack.addArrangedSubview(fieldContainer)
                fieldConstraints.append(contentsOf: [
                    name.leadingAnchor.constraint(equalTo: fieldContainer.leadingAnchor),
                    name.trailingAnchor.constraint(equalTo: dividerLayoutGuide.leadingAnchor),
                    name.topAnchor.constraint(equalTo: fieldContainer.topAnchor),
                    name.bottomAnchor.constraint(equalTo: fieldContainer.bottomAnchor),
                    
                    value.leadingAnchor.constraint(equalTo: dividerLayoutGuide.trailingAnchor),
                    value.trailingAnchor.constraint(equalTo: fieldContainer.trailingAnchor),
                    value.topAnchor.constraint(equalTo: fieldContainer.topAnchor),
                    value.bottomAnchor.constraint(equalTo: fieldContainer.bottomAnchor),
                    
                    name.widthAnchor.constraint(greaterThanOrEqualTo: value.widthAnchor, multiplier: 0.5),
                    name.widthAnchor.constraint(lessThanOrEqualTo: value.widthAnchor, multiplier: 2),
                ])
            }
        }
        
        NSLayoutConstraint.activate(fieldConstraints)
    }
    
}

private class ProfileFieldValueView: UIView {
    weak var navigationDelegate: TuskerNavigationDelegate? {
        didSet {
            textView.navigationDelegate = navigationDelegate
        }
    }
    
    private let account: AccountMO
    private let field: Account.Field
    
    private let textView = ContentTextView()
    private var iconView: UIView?
    
    init(field: Account.Field, account: AccountMO) {
        self.account = account
        self.field = field
        
        super.init(frame: .zero)
        
        textView.isSelectable = false
        textView.backgroundColor = .clear
        textView.defaultFont = .preferredFont(forTextStyle: .body)
        textView.monospaceFont = UIFontMetrics.default.scaledFont(for: .monospacedSystemFont(ofSize: 17, weight: .regular))
        textView.adjustsFontForContentSizeCategory = true
        textView.setTextFromHtml(field.value)
        textView.setEmojis(account.emojis, identifier: account.id)
        textView.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        textView.translatesAutoresizingMaskIntoConstraints = false
        addSubview(textView)
        
        let textViewTrailingConstraint: NSLayoutConstraint
        
        if field.verifiedAt != nil {
            var config = UIButton.Configuration.plain()
            config.image = UIImage(systemName: "checkmark")
            config.baseForegroundColor = .systemGreen
            let icon = UIButton(configuration: config)
            self.iconView = icon
            icon.translatesAutoresizingMaskIntoConstraints = false
            icon.setContentHuggingPriority(.defaultHigh, for: .horizontal)
            icon.addTarget(self, action: #selector(verifiedIconTapped), for: .touchUpInside)
            icon.isPointerInteractionEnabled = true
            icon.accessibilityLabel = "Verified link"
            addSubview(icon)
            textViewTrailingConstraint = textView.trailingAnchor.constraint(equalTo: icon.leadingAnchor, constant: -4)
            NSLayoutConstraint.activate([
                icon.centerYAnchor.constraint(equalTo: centerYAnchor),
                icon.trailingAnchor.constraint(equalTo: trailingAnchor),
            ])
        } else {
            textViewTrailingConstraint = textView.trailingAnchor.constraint(equalTo: trailingAnchor)
        }
        
        NSLayoutConstraint.activate([
            textView.leadingAnchor.constraint(equalTo: leadingAnchor),
            textViewTrailingConstraint,
            textView.topAnchor.constraint(equalTo: topAnchor),
            textView.bottomAnchor.constraint(equalTo: bottomAnchor),
        ])
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func setTextAlignment(_ alignment: NSTextAlignment) {
        textView.textAlignment = alignment
    }
    
    @objc private func verifiedIconTapped() {
        guard let navigationDelegate else {
            return
        }
        let view = ProfileFieldVerificationView(
            acct: account.acct,
            verifiedAt: field.verifiedAt!,
            linkText: textView.text,
            navigationDelegate: navigationDelegate
        )
        let host = UIHostingController(rootView: view)
        let toPresent: UIViewController
        if traitCollection.horizontalSizeClass == .compact || traitCollection.verticalSizeClass == .compact {
            toPresent = UINavigationController(rootViewController: host)
            toPresent.modalPresentationStyle = .pageSheet
            let sheetPresentationController = toPresent.sheetPresentationController!
            sheetPresentationController.detents = [
                .medium()
            ]
        } else {
            host.modalPresentationStyle = .popover
            let popoverPresentationController = host.popoverPresentationController!
            popoverPresentationController.sourceView = iconView
            host.preferredContentSize = host.sizeThatFits(in: CGSize(width: 400, height: CGFloat.infinity))
            toPresent = host
        }
        navigationDelegate.present(toPresent, animated: true)
    }
}

private struct ProfileFieldVerificationView: View {
    let acct: String
    let verifiedAt: Date
    let linkText: String
    let navigationDelegate: TuskerNavigationDelegate
    
    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            firstLine
            secondLine
        }
        .padding()
        .navigationTitle(Text("Verified Link"))
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .cancellationAction) {
                Button("Done") {
                    navigationDelegate.dismiss(animated: true)
                }
            }
        }
        .environment(\.openURL, OpenURLAction(handler: { url in
            // dismiss the sheet/popover first
            navigationDelegate.dismiss(animated: true) {
                navigationDelegate.selected(url: url)
            }
            return .handled
        }))
    }
    
    private var firstLine: Text {
        var attrStr: AttributedString = "This link has been verified by your instance, "
        var instance = AttributedString(navigationDelegate.apiController!.instanceURL.host!)
        instance.font = .body.bold()
        attrStr += instance
        attrStr += "."
        return Text(attrStr)
    }
    
    private var secondLine: Text {
        var attrStr: AttributedString = "The page at "
        var linkStr: AttributedString
        if linkText.count > 43 {
            linkStr = AttributedString(linkText.prefix(40) + "…")
        } else {
            linkStr = AttributedString(linkText)
        }
        linkStr.link = URL(string: linkText)
        attrStr += linkStr
        attrStr += " was confirmed to link back to "
        var acctStr = AttributedString("@\(acct)")
        acctStr.font = .body.bold()
        attrStr += acctStr
        attrStr += AttributedString(" as of \(verifiedAt.formatted(date: .abbreviated, time: .shortened)).")
        return Text(attrStr)
    }
}