// BundleImporter.swift
// 导入 ZIP 包并解析为 BundleIndex

import Foundation
import ZIPFoundation
import UniformTypeIdentifiers
#if canImport(UIKit)
import UIKit
#endif

@available(macOS 10.15, iOS 13.0, *)
final class BundleImporter: NSObject, ObservableObject {
    @Published var bundleIndex: BundleIndex?
    @Published var progressMessage: String? = nil
    @Published var errorMessage: String? = nil
    @Published var lastImportedURL: URL? = nil

    var index: BundleIndex? { bundleIndex }
    private let fm = FileManager.default

    // 公开导入方法供CLI使用
    func importZipFile(at url: URL) async throws -> BundleIndex {
        let ts = Int(Date().timeIntervalSince1970)
        let baseDir = try bundleBaseDirectory()
        let target = baseDir.appendingPathComponent("bundle_\(ts)")
        try fm.createDirectory(at: target, withIntermediateDirectories: true)
        try fm.unzipItem(at: url, to: target)
        let idx = try parseBundle(at: target)
        await MainActor.run {
            self.bundleIndex = idx
            self.lastImportedURL = url
        }
        return idx
    }

    // iOS 选择器
    func presentPicker() {
        #if canImport(UIKit)
        let types: [UTType] = [UTType.filenameExtension("zip")!]
        let picker = UIDocumentPickerViewController(forOpeningContentTypes: types, asCopy: true)
        picker.delegate = self
        picker.allowsMultipleSelection = false
        UIApplication.shared.firstKeyWindow?.rootViewController?.present(picker, animated: true)
        #else
        print("[BundleImporter] presentPicker() unsupported on this platform")
        #endif
    }

    // 存储目录
    private func bundleBaseDirectory() throws -> URL {
        let appSup = try fm.url(for: .applicationSupportDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
        let dir = appSup.appendingPathComponent("ImportedBundle")
        if !fm.fileExists(atPath: dir.path) { try fm.createDirectory(at: dir, withIntermediateDirectories: true) }
        return dir
    }

    @MainActor private func update(message: String?) { self.progressMessage = message }

    // 解析内容
    private func parseBundle(at dir: URL) throws -> BundleIndex {
        func load<T:Decodable>(_ name: String, _ type: T.Type) throws -> T {
            let data = try Data(contentsOf: dir.appendingPathComponent(name))
            return try JSONDecoder().decode(T.self, from: data)
        }
        let books: [BookMeta] = try load("books_meta.json", [BookMeta].self)
        let stats: StatsPayload = try load("stats.json", StatsPayload.self)
        let introData = try? Data(contentsOf: dir.appendingPathComponent("bookintro.json"))
        let bookIntro = (introData.flatMap { try? JSONDecoder().decode([String:String].self, from: $0) }) ?? [:]

        let annotationsRaw = try Data(contentsOf: dir.appendingPathComponent("annotations.json"))
        let anyMap = (try? JSONSerialization.jsonObject(with: annotationsRaw)) as? [String:Any] ?? [:]
        var annMap: [String:[AnnotationRow]] = [:]
        for (k,v) in anyMap {
            guard let arr = v as? [[String:Any]] else { continue }
            let rows: [AnnotationRow] = arr.compactMap { d in
                guard let uuid = d["uuid"] as? String else { return nil }
                return AnnotationRow(
                    uuid: uuid,
                    creationdate: d["creationdate"] as? String,
                    idref: d["idref"] as? String,
                    filepos: d["filepos"] as? String,
                    selected: d["selected"] as? String,
                    note: d["note"] as? String
                )
            }
            annMap[k] = rows
        }
        return BundleIndex(books: books, stats: stats, bookIntro: bookIntro, annotationsMap: annMap)
    }

    // 导入执行
    private func importZip(at url: URL) async {
        await update(message: "解压中...")
        do {
            let ts = Int(Date().timeIntervalSince1970)
            let baseDir = try bundleBaseDirectory()
            let target = baseDir.appendingPathComponent("bundle_\(ts)")
            try fm.createDirectory(at: target, withIntermediateDirectories: true)
            try fm.unzipItem(at: url, to: target)
            await update(message: "解析 JSON...")
            let idx = try parseBundle(at: target)
            await MainActor.run {
                self.bundleIndex = idx
                self.lastImportedURL = url
            }
            await update(message: nil)
        } catch {
            await MainActor.run { self.errorMessage = error.localizedDescription }
            await update(message: nil)
        }
    }
}

#if canImport(UIKit)
extension BundleImporter: UIDocumentPickerDelegate {
    func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
        guard let url = urls.first else { return }
        lastImportedURL = url
        Task { await importZip(at: url) }
    }
}

extension UIApplication {
    var firstKeyWindow: UIWindow? {
        self.connectedScenes.compactMap { $0 as? UIWindowScene }
            .flatMap { $0.windows }
            .first { $0.isKeyWindow }
    }
}
#endif