//
//  MyPetsViewController.swift
//  VenusKitto
//
//  Created by Neoa on 2025/8/27.
//

import Foundation
import UIKit

// MARK: - FlexibleCode (string or int)
fileprivate struct FlexibleCode: Codable {
    let raw: String
    init(from decoder: Decoder) throws {
        let c = try decoder.singleValueContainer()
        if let s = try? c.decode(String.self) { raw = s }
        else if let i = try? c.decode(Int.self) { raw = String(i) }
        else { raw = "" }
    }
}

// MARK: - 我的宠物 列表页
final class MyPetsViewController: UIViewController {
    // UI
    private let titleLabel: UILabel = {
        let l = UILabel()
        l.text = "我的宠物"
        l.font = .systemFont(ofSize: 28, weight: .semibold)
        l.textColor = UIColor(hex: "#2B2B2B")
        return l
    }()
    private let scrollView = UIScrollView()
    private let contentView = UIView()
    private let stack = UIStackView()

    private let imageCache = NSCache<NSString, UIImage>()

    private var petsData: [HomeViewController.PetSummary] = []
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor(hex: "#FFFEFC")
        
        if let backImage = UIImage(named: "AddPet385") {
            let backButton = UIBarButtonItem(image: backImage.withRenderingMode(.alwaysOriginal), style: .plain, target: self, action: #selector(tapCancel))
            navigationItem.leftBarButtonItem = backButton
        }

        buildUI()
        fetchPets()
        
        NotificationCenter.default.addObserver(self,
                                               selector: #selector(handlePetDidSave(_:)),
                                               name: .petDidSave,
                                               object: nil)

    }
    
    // 收到通知后刷新列表
    @objc private func handlePetDidSave(_ note: Notification) {
        DispatchQueue.main.async { [weak self] in
            self?.fetchPets()
        }
    }

    // 记得移除监听
    deinit {
        NotificationCenter.default.removeObserver(self, name: .petDidSave, object: nil)
    }
    
    @objc private func tapCancel() { navigationController?.popViewController(animated: true)
    }


    private func buildUI() {
        // 顶部标题
        view.addSubview(titleLabel)
        titleLabel.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            titleLabel.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 12),
            titleLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 16)
        ])

        // 滚动容器
        view.addSubview(scrollView)
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        scrollView.showsVerticalScrollIndicator = false
        NSLayoutConstraint.activate([
            scrollView.topAnchor.constraint(equalTo: titleLabel.bottomAnchor, constant: 12),
            scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        ])

        scrollView.addSubview(contentView)
        contentView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            contentView.topAnchor.constraint(equalTo: scrollView.topAnchor),
            contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
            contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor),
            contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
            contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor)
        ])

        // 垂直栈放卡片
        stack.axis = .vertical
        stack.spacing = 12
        stack.alignment = .fill
        contentView.addSubview(stack)
        stack.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            stack.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 12),
            stack.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 12),
            stack.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -12),
            stack.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -24)
        ])
    }

    // MARK: - Networking
    private struct PetListResp: Codable {
        let code: FlexibleCode
        let msg: String?
        let data: [HomeViewController.PetSummary]
    }

    private func fetchPets() {
        let userId = UserDefaults.standard.string(forKey: "userId") ?? ""
        guard !userId.isEmpty else {
            #if DEBUG
            print("❌ 缺少 userId，无法请求宠物列表")
            #endif
            return
        }
        var comps = URLComponents(string: "\(baseURL)/petRecordPet/queryPetList")
        comps?.queryItems = [URLQueryItem(name: "userId", value: userId)]
        guard let url = comps?.url else { return }

        var req = URLRequest(url: url)
        req.httpMethod = "GET"
        req.setValue("application/json", forHTTPHeaderField: "Content-Type")
        if let token = UserDefaults.standard.string(forKey: "userToken") {
            req.setValue(token, forHTTPHeaderField: "Authorization")
        }
        print("🐶 GET: \(url.absoluteString)")

        URLSession.shared.dataTask(with: req) { [weak self] data, resp, err in
            if let http = resp as? HTTPURLResponse { print("🐶 status: \(http.statusCode)") }
            if let err = err { print("🐶 error: \(err)"); return }
            guard let data = data else { print("🐶 empty data"); return }
            do {
                let decoder = JSONDecoder()
                let r = try decoder.decode(PetListResp.self, from: data)
                if r.code.raw == "200" {
                    DispatchQueue.main.async { self?.render(pets: r.data) }
                } else {
                    print("🐶 server msg: \(r.msg ?? "-") code=\(r.code.raw)")
                }
            } catch {
                print("🐶 decode error: \(error)")
            }
        }.resume()
    }

    // MARK: - UI render
    private func render(pets: [HomeViewController.PetSummary]) {
        self.petsData = pets
        // 清空旧卡片
        stack.arrangedSubviews.forEach { v in
            stack.removeArrangedSubview(v)
            v.removeFromSuperview()
        }
        guard !pets.isEmpty else { return }

        let placeholder = UIImage(named: "Home372") ?? UIImage(systemName: "pawprint")!
        for (idx, p) in pets.enumerated() {
            let card = PetHeaderCard()
            card.translatesAutoresizingMaskIntoConstraints = false
            card.heightAnchor.constraint(equalToConstant: 103).isActive = true

            // 点击跳转
            card.isUserInteractionEnabled = true
            card.tag = idx
            let tap = UITapGestureRecognizer(target: self, action: #selector(cardTapped(_:)))
            card.addGestureRecognizer(tap)

            // 文案
            let breed = p.breedName ?? "宠物品种"
            let ageText = (p.age?.isEmpty == false) ? "\(p.age!)岁" : "年龄"
            let daysText = (p.togetherDays?.isEmpty == false) ? "一起生活的第\(p.togetherDays!)天" : "一起生活的第XX天"

            // 先占位
            card.configure(avatar: placeholder, name: p.name, breed: breed, ageText: ageText, daysText: daysText)

            // 异步加载头像
            if let urlStr = p.avatar, let url = URL(string: urlStr) {
                loadImage(from: url) { img in
                    card.configure(avatar: img ?? placeholder, name: p.name, breed: breed, ageText: ageText, daysText: daysText)
                }
            }

            stack.addArrangedSubview(card)
        }
    }
    
    @objc private func cardTapped(_ g: UITapGestureRecognizer) {
        guard let v = g.view else { return }
        let index = v.tag
        guard index >= 0, index < petsData.count else { return }
        let pet = petsData[index]
        let vc = PetDetailViewController(pet: pet)
        navigationController?.pushViewController(vc, animated: true)
    }
    
    // MARK: - Image loader (no 3rd-party)
    private func loadImage(from url: URL, completion: @escaping (UIImage?) -> Void) {
        let key = url.absoluteString as NSString
        if let c = imageCache.object(forKey: key) {
            completion(c)
            return
        }
        URLSession.shared.dataTask(with: url) { [weak self] data, _, _ in
            var img: UIImage? = nil
            if let data = data { img = UIImage(data: data) }
            if let i = img { self?.imageCache.setObject(i, forKey: key) }
            DispatchQueue.main.async { completion(img) }
        }.resume()
    }
}