//
//  PhotoPickerVC.swift
//  QuickLocation
//

import UIKit
import Photos

final class PhotoPickerVC: BaseViewController {

    override var isNavigationBarHidden: Bool { true }
    override var preferredStatusBarStyle: UIStatusBarStyle { .lightContent }

    var onConfirm: (([UIImage]) -> Void)?

    private let maxCount: Int
    private let store = PhotoPickerStore()
    private var rootView: PhotoPickerView!
    private var selected: [PHAsset] = []
    private var currentAlbumIndex = 0
    private var isExporting = false

    init(maxCount: Int = 9) {
        self.maxCount = max(1, maxCount)
        super.init(nibName: nil, bundle: nil)
        modalPresentationStyle = .fullScreen
    }

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

    override func loadView() {
        rootView = PhotoPickerView(store: store, maxCount: maxCount)
        view = rootView
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        rootView.bindAlbumStore(store)
        bind()
        store.requestAccess { [weak self] granted in
            guard let self else { return }
            guard granted else {
                DLToast.show(text: "请在设置中开启相册权限")
                self.dismiss(animated: true)
                return
            }
            self.store.reloadAlbums()
            self.currentAlbumIndex = 0
            self.rootView.reloadAlbums(currentIndex: 0)
            self.rootView.reloadGrid()
        }
    }

    private func bind() {
        rootView.onClose = { [weak self] in
            self?.dismiss(animated: true)
        }
        rootView.onToggleAlbum = { [weak self] in
            guard let self else { return }
            self.rootView.isAlbumOpen.toggle()
        }
        rootView.onPickAlbum = { [weak self] index in
            guard let self, self.store.albums.indices.contains(index) else { return }
            self.currentAlbumIndex = index
            self.store.loadAssets(in: self.store.albums[index])
            self.rootView.reloadAlbums(currentIndex: index)
            self.rootView.reloadGrid()
            self.rootView.isAlbumOpen = false
        }
        rootView.onSelectAsset = { [weak self] index in
            self?.toggleAsset(at: index)
        }
        rootView.onPreview = { [weak self] in
            self?.showPreview()
        }
        rootView.onConfirm = { [weak self] in
            self?.confirmSelection()
        }
    }

    private func toggleAsset(at index: Int) {
        guard store.assets.indices.contains(index) else { return }
        let asset = store.assets[index]
        if let idx = selected.firstIndex(where: { $0.localIdentifier == asset.localIdentifier }) {
            selected.remove(at: idx)
        } else {
            if selected.count >= maxCount {
                rootView.showLimitToast()
                return
            }
            selected.append(asset)
        }
        rootView.applySelection(selected.map(\.localIdentifier))
    }

    private func showPreview() {
        guard !selected.isEmpty else { return }
        let vc = PhotoPickerPreviewVC(assets: selected, startIndex: 0, store: store)
        present(vc, animated: true)
    }

    private func confirmSelection() {
        guard !isExporting else { return }
        guard !selected.isEmpty else {
            dismiss(animated: true)
            return
        }
        isExporting = true
        DLToast.showLoading()
        store.requestFullImages(for: selected) { [weak self] images in
            DLToast.dismiss()
            guard let self else { return }
            self.isExporting = false
            self.dismiss(animated: true) {
                self.onConfirm?(images)
            }
        }
    }
}