//
//  PhotoPickerAlbumView.swift
//  QuickLocation
//

import UIKit
import Photos

final class PhotoPickerAlbumView: UIView, UITableViewDataSource, UITableViewDelegate {

    var onSelect: ((Int) -> Void)?

    private var albums: [PhotoAlbum] = []
    private var selectedIndex = 0
    private var store: PhotoPickerStore?

    private lazy var tableView: UITableView = {
        let tv = UITableView(frame: .zero, style: .plain)
        tv.backgroundColor = UIColor(hexStr: "#2C2C2E")
        tv.separatorColor = UIColor.white.withAlphaComponent(0.12)
        tv.separatorInset = UIEdgeInsets(top: 0, left: 76, bottom: 0, right: 0)
        tv.rowHeight = 64
        tv.dataSource = self
        tv.delegate = self
        tv.tableFooterView = UIView()
        tv.register(PhotoPickerAlbumCell.self, forCellReuseIdentifier: "cell")
        return tv
    }()

    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = UIColor(hexStr: "#2C2C2E")
        addSubview(tableView)
        tableView.layoutChain.edges()
    }

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

    func reload(albums: [PhotoAlbum], selectedIndex: Int) {
        self.albums = albums
        self.selectedIndex = selectedIndex
        tableView.reloadData()
    }

    func bindStore(_ store: PhotoPickerStore) {
        self.store = store
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        albums.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! PhotoPickerAlbumCell
        let album = albums[indexPath.row]
        cell.configure(album: album, selected: indexPath.row == selectedIndex, store: store)
        return cell
    }

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        selectedIndex = indexPath.row
        tableView.reloadData()
        onSelect?(indexPath.row)
    }
}

private final class PhotoPickerAlbumCell: UITableViewCell {
    private let coverView = UIImageView()
    private let titleLab = UILabel()
    private let tickView = UIImageView()
    private var assetId = ""
    private var requestId: PHImageRequestID = PHInvalidImageRequestID

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        backgroundColor = UIColor(hexStr: "#2C2C2E")
        selectionStyle = .none
        coverView.contentMode = .scaleAspectFill
        coverView.clipsToBounds = true
        coverView.cornerRadius = 4
        coverView.backgroundColor = UIColor.white.withAlphaComponent(0.08)
        titleLab.font = .systemFont(ofSize: 16)
        titleLab.textColor = .white
        let config = UIImage.SymbolConfiguration(pointSize: 15, weight: .semibold)
        tickView.image = UIImage(systemName: "checkmark", withConfiguration: config)
        tickView.tintColor = UIColor(hexStr: "#007AFF")
        tickView.contentMode = .scaleAspectFit
        contentView.addSubview(coverView)
        contentView.addSubview(titleLab)
        contentView.addSubview(tickView)
        coverView.layoutChain.left(16).centerY().width(48).height(48)
        titleLab.layoutChain.leftToRightOfView(coverView, offset: 12).centerY().right(40)
        tickView.layoutChain.right(16).centerY().width(18).height(18)
    }

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

    func configure(album: PhotoAlbum, selected: Bool, store: PhotoPickerStore?) {
        titleLab.text = "\(album.title) (\(album.count))"
        tickView.isHidden = !selected
        coverView.image = nil
        assetId = album.coverAsset?.localIdentifier ?? ""
        guard let store, let asset = album.coverAsset else { return }
        if requestId != PHInvalidImageRequestID {
            store.cancelRequest(requestId)
        }
        requestId = store.requestThumbnail(for: asset, size: CGSize(width: 48, height: 48)) { [weak self] image in
            guard let self, self.assetId == asset.localIdentifier else { return }
            self.coverView.image = image
        }
    }
}