//
//  FeedbackVC.swift
//  QuickLocation
//

import UIKit
import RxSwift
import RxCocoa


final class FeedbackVC: BaseViewController {

    private enum FeedbackCategory: String, CaseIterable {
        case feature = "功能问题"
        case suggestion = "优化建议"
        case other = "其他"
    }

    private struct FeedbackDraft {
        let category: FeedbackCategory
        let detail: String
        let images: [UIImage]
        let contact: String
    }

    private var rootView: FeedbackView!
    private var selectedCategory: FeedbackCategory = .feature
    private var selectedImages: [UIImage] = []
    private var pendingDraft: FeedbackDraft?
    private var isSubmitting = false
    private let contextText: String

    init(contextText: String = "") {
        self.contextText = contextText.trimmingCharacters(in: .whitespacesAndNewlines)
        super.init(nibName: nil, bundle: nil)
    }

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

    override func loadView() {
        rootView = FeedbackView(frame: UIScreen.main.bounds)
        view = rootView
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        bind()
    }

    private func bind() {
        rootView.navView.onBackTapped = { [weak self] in
            guard self?.isSubmitting == false else { return }
            self?.navigationController?.popViewController(animated: true)
        }

        rootView.categoryButtons.forEach { button in
            button.addTarget(self, action: #selector(categoryTapped(_:)), for: .touchUpInside)
        }

        rootView.detailTextView.rx.text.orEmpty
            .subscribe(onNext: { [weak self] text in
                self?.handleDetailChange(text)
            })
            .disposed(by: disposeBag)

        rootView.contactTextField.rx.controlEvent(.editingDidEndOnExit)
            .subscribe(onNext: { [weak self] in
                self?.rootView.contactTextField.resignFirstResponder()
            })
            .disposed(by: disposeBag)

        rootView.onAddImage = { [weak self] in
            self?.showAlbum()
        }

        rootView.onDeleteImage = { [weak self] index in
            guard let self, self.selectedImages.indices.contains(index) else { return }
            self.selectedImages.remove(at: index)
            self.rootView.updateImages(self.selectedImages)
        }

        rootView.saveBtn.rx.tap
            .subscribe(onNext: { [weak self] in
                self?.submit()
            })
            .disposed(by: disposeBag)
    }

    @objc private func categoryTapped(_ sender: UIButton) {
        let categories = FeedbackCategory.allCases
        guard categories.indices.contains(sender.tag) else { return }
        let category = categories[sender.tag]
        selectedCategory = category
        rootView.updateCategory(selectedIndex: sender.tag)
    }

    private func handleDetailChange(_ text: String) {
        let limitedText = text.count > 200 ? String(text.prefix(200)) : text
        if limitedText != text {
            rootView.detailTextView.text = limitedText
            rootView.detailTextView.selectedRange = NSRange(location: limitedText.count, length: 0)
        }
        rootView.updateDetail(text: limitedText)
    }

    private func showAlbum() {
        let remainingCount = 3 - selectedImages.count
        guard remainingCount > 0, !isSubmitting else { return }
        let picker = PhotoPickerVC(maxCount: remainingCount)
        picker.onConfirm = { [weak self] images in
            guard let self else { return }
            self.selectedImages.append(contentsOf: images.prefix(remainingCount))
            self.selectedImages = Array(self.selectedImages.prefix(3))
            self.rootView.updateImages(self.selectedImages)
        }
        present(picker, animated: true)
    }

    private func submit() {
        guard !isSubmitting else { return }
        view.endEditing(true)

        let detail = (rootView.detailTextView.text ?? "")
            .trimmingCharacters(in: .whitespacesAndNewlines)
        guard !detail.isEmpty else {
            DLToast.show(text: "请补充详细问题或意见")
            return
        }

        pendingDraft = FeedbackDraft(
            category: selectedCategory,
            detail: detail,
            images: selectedImages,
            contact: (rootView.contactTextField.text ?? "")
                .trimmingCharacters(in: .whitespacesAndNewlines)
        )
        isSubmitting = true
        rootView.setSubmitting(true)

        guard let draft = pendingDraft else { return }
        let uploadRequests: [Observable<String>]
        do {
            uploadRequests = try draft.images.map { image in
                guard let data = compressedJPEG(from: image) else {
                    throw feedbackError("图片处理失败，请重新选择")
                }
                return UploadService.uploadURL(data, kind: .jpeg, scene: "feedback")
            }
        } catch {
            finishSubmission(error: error)
            return
        }

        DLToast.showLoading()
        let imageURLs = uploadRequests.isEmpty
            ? Observable.just([String]())
            : Observable.zip(uploadRequests)
        imageURLs
            .flatMap { [weak self] urls -> Observable<ResponseModel> in
                guard let self else { return .empty() }
                var type = draft.category.rawValue
                if !self.contextText.isEmpty {
                    type += "(\(self.contextText))"
                }
                return UserService.feedback(
                    type: type,
                    content: draft.detail,
                    contact: draft.contact,
                    images: urls
                )
            }
            .subscribe(onNext: { [weak self] _ in
                self?.showSuccess()
            }, onError: { [weak self] error in
                self?.finishSubmission(error: error)
            })
            .disposed(by: disposeBag)
    }

    private func showSuccess() {
        DLToast.dismiss()

        let successView = FeedbackSuccessView()
        successView.show(in: view)
        DispatchQueue.main.asyncAfter(deadline: .now() + 1.5) { [weak successView] in
            guard let successView else { return }
            successView.dismiss {
                AppRouter.shared.popOrDismiss()
            }
        }
    }

    private func finishSubmission(error: Error) {
        DLToast.dismiss()
        pendingDraft = nil
        isSubmitting = false
        rootView.setSubmitting(false)
        DLToast.show(text: error.localizedDescription)
    }

    private func compressedJPEG(from image: UIImage) -> Data? {
        let maxEdge: CGFloat = 1280
        let longest = max(image.size.width, image.size.height)
        let output: UIImage
        if longest > maxEdge, longest > 0 {
            let scale = maxEdge / longest
            let size = CGSize(
                width: (image.size.width * scale).rounded(),
                height: (image.size.height * scale).rounded()
            )
            let format = UIGraphicsImageRendererFormat.default()
            format.scale = 1
            format.opaque = true
            output = UIGraphicsImageRenderer(size: size, format: format).image { _ in
                image.draw(in: CGRect(origin: .zero, size: size))
            }
        } else {
            output = image
        }
        return output.jpegData(compressionQuality: 0.65)
            ?? image.jpegData(compressionQuality: 0.8)
    }

    private func feedbackError(_ message: String) -> NSError {
        NSError(
            domain: "Feedback",
            code: -1,
            userInfo: [NSLocalizedDescriptionKey: message]
        )
    }
}