//
//  AttachmentsContainerView.swift
//  Tusker
//
//  Created by Shadowfacts on 6/16/19.
//  Copyright © 2019 Shadowfacts. All rights reserved.
//

import UIKit
import Pachyderm

class AttachmentsContainerView: UIView {

    var delegate: AttachmentViewDelegate?
    
    override func awakeFromNib() {
        super.awakeFromNib()
        
        self.isUserInteractionEnabled = true
    }
    
    func updateUI(status: Status) {
        let attachments = status.attachments.filter { $0.kind == .image }
        
        if attachments.count > 0 {
            self.isHidden = false
            
            let mainView: UIView
            switch attachments.count {
            case 1:
                mainView = createAttachmentView(attachments[0])
            case 2:
                mainView = createAttachmentsStack(axis: .horizontal, arrangedSubviews: [
                    createAttachmentView(attachments[0]),
                    createAttachmentView(attachments[1])
                ])
            case 3:
                mainView = createAttachmentsStack(axis: .horizontal, arrangedSubviews: [
                    createAttachmentView(attachments[0]),
                    createAttachmentsStack(axis: .vertical, arrangedSubviews: [
                        createAttachmentView(attachments[1]),
                        createAttachmentView(attachments[2])
                    ])
                ])
            case 4:
                mainView = createAttachmentsStack(axis: .horizontal, arrangedSubviews: [
                    createAttachmentsStack(axis: .vertical, arrangedSubviews: [
                        createAttachmentView(attachments[0]),
                        createAttachmentView(attachments[2])
                    ]),
                    createAttachmentsStack(axis: .vertical, arrangedSubviews: [
                        createAttachmentView(attachments[1]),
                        createAttachmentView(attachments[3])
                    ])
                ])
            default:
                fatalError("Too many attachments")
            }
            
            addSubview(mainView)
            NSLayoutConstraint.activate([
                mainView.leadingAnchor.constraint(equalTo: leadingAnchor),
                mainView.trailingAnchor.constraint(equalTo: trailingAnchor),
                mainView.topAnchor.constraint(equalTo: topAnchor),
                mainView.bottomAnchor.constraint(equalTo: bottomAnchor)
            ])
        } else {
            self.isHidden = true
            subviews.forEach { $0.removeFromSuperview() }
        }
    }
    
    private func createAttachmentView(_ attachment: Attachment) -> AttachmentView {
        let attachmentView = AttachmentView(attachment: attachment)
        attachmentView.delegate = delegate
        attachmentView.translatesAutoresizingMaskIntoConstraints = false
        return attachmentView
    }
    
    private func createAttachmentsStack(axis: NSLayoutConstraint.Axis, arrangedSubviews: [UIView]) -> UIStackView {
        let stack = UIStackView(arrangedSubviews: arrangedSubviews)
        stack.axis = axis
        stack.spacing = 8
        stack.translatesAutoresizingMaskIntoConstraints = false
        return stack
    }

}