//
//  AppRestrictShared.swift
//  Shared between main app and Screen Time extensions.
//

import Foundation
import FamilyControls
import ManagedSettings
import UIKit

enum AppRestrictShared {
    static let appGroupId = "group.cn.zuomeng.jisuloca"
    static let storeName = ManagedSettingsStore.Name("appRestrict")
    static let activityName = "appRestrict.monitoring"

    static let selectionKey = "appRestrict.selection"
    static let enabledTokensKey = "appRestrict.enabledTokens"
    static let linksKey = "appRestrict.links"
    static let shieldConfigKey = "appRestrict.shieldConfig"
    static let customImageFileName = "shield_custom.jpg"

    static var defaults: UserDefaults {
        UserDefaults(suiteName: appGroupId) ?? .standard
    }

    static var containerURL: URL? {
        FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: appGroupId)
    }

    static var customImageURL: URL? {
        containerURL?.appendingPathComponent(customImageFileName)
    }

    static func makeStore() -> ManagedSettingsStore {
        ManagedSettingsStore(named: storeName)
    }
}

struct AppRestrictLinkRecord: Codable, Equatable {
    let catalogId: String
    let tokenData: Data
    let displayName: String?
    let iconURL: String?

    init(catalogId: String, tokenData: Data, displayName: String? = nil, iconURL: String? = nil) {
        self.catalogId = catalogId
        self.tokenData = tokenData
        self.displayName = displayName
        self.iconURL = iconURL
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        catalogId = try container.decode(String.self, forKey: .catalogId)
        tokenData = try container.decode(Data.self, forKey: .tokenData)
        displayName = try container.decodeIfPresent(String.self, forKey: .displayName)
        iconURL = try container.decodeIfPresent(String.self, forKey: .iconURL)
    }
}

struct AppRestrictShieldConfig: Codable, Equatable {
    enum ImageSource: String, Codable {
        case presetDefault
        case presetFocus
        case presetCalm
        case album
    }

    var title: String
    var subtitle: String
    var primaryButtonLabel: String
    var imageSource: ImageSource

    static let `default` = AppRestrictShieldConfig(
        title: "该应用已被锁定",
        subtitle: "专注当下，稍后再回来吧",
        primaryButtonLabel: "知道了",
        imageSource: .presetDefault
    )
}

enum AppRestrictTokenCodec {
    static func encode(_ token: ApplicationToken) -> Data? {
        try? PropertyListEncoder().encode(token)
    }

    static func decode(_ data: Data) -> ApplicationToken? {
        try? PropertyListDecoder().decode(ApplicationToken.self, from: data)
    }

    static func encodeSelection(_ selection: FamilyActivitySelection) -> Data? {
        try? PropertyListEncoder().encode(selection)
    }

    static func decodeSelection(_ data: Data) -> FamilyActivitySelection? {
        try? PropertyListDecoder().decode(FamilyActivitySelection.self, from: data)
    }

    static func encodeTokenSet(_ tokens: Set<ApplicationToken>) -> Data? {
        let datas = tokens.compactMap { encode($0) }
        return try? PropertyListEncoder().encode(datas)
    }

    static func decodeTokenSet(_ data: Data) -> Set<ApplicationToken> {
        guard let datas = try? PropertyListDecoder().decode([Data].self, from: data) else {
            return []
        }
        return Set(datas.compactMap { decode($0) })
    }
}

enum AppRestrictSharedStore {
    static var selection: FamilyActivitySelection {
        get {
            guard let data = AppRestrictShared.defaults.data(forKey: AppRestrictShared.selectionKey),
                  let value = AppRestrictTokenCodec.decodeSelection(data) else {
                return FamilyActivitySelection()
            }
            return value
        }
        set {
            if let data = AppRestrictTokenCodec.encodeSelection(newValue) {
                AppRestrictShared.defaults.set(data, forKey: AppRestrictShared.selectionKey)
            }
        }
    }

    static var enabledTokens: Set<ApplicationToken> {
        get {
            guard let data = AppRestrictShared.defaults.data(forKey: AppRestrictShared.enabledTokensKey) else {
                return []
            }
            return AppRestrictTokenCodec.decodeTokenSet(data)
        }
        set {
            if let data = AppRestrictTokenCodec.encodeTokenSet(newValue) {
                AppRestrictShared.defaults.set(data, forKey: AppRestrictShared.enabledTokensKey)
            } else {
                AppRestrictShared.defaults.removeObject(forKey: AppRestrictShared.enabledTokensKey)
            }
        }
    }

    static var links: [AppRestrictLinkRecord] {
        get {
            guard let data = AppRestrictShared.defaults.data(forKey: AppRestrictShared.linksKey),
                  let value = try? JSONDecoder().decode([AppRestrictLinkRecord].self, from: data) else {
                return []
            }
            return value
        }
        set {
            if let data = try? JSONEncoder().encode(newValue) {
                AppRestrictShared.defaults.set(data, forKey: AppRestrictShared.linksKey)
            }
        }
    }

    static var shieldConfig: AppRestrictShieldConfig {
        get {
            guard let data = AppRestrictShared.defaults.data(forKey: AppRestrictShared.shieldConfigKey),
                  let value = try? JSONDecoder().decode(AppRestrictShieldConfig.self, from: data) else {
                return .default
            }
            return value
        }
        set {
            if let data = try? JSONEncoder().encode(newValue) {
                AppRestrictShared.defaults.set(data, forKey: AppRestrictShared.shieldConfigKey)
            }
        }
    }

    static func linkRecord(for token: ApplicationToken) -> AppRestrictLinkRecord? {
        guard let data = AppRestrictTokenCodec.encode(token) else { return nil }
        return links.first(where: { $0.tokenData == data })
    }

    static func catalogId(for token: ApplicationToken) -> String? {
        linkRecord(for: token)?.catalogId
    }

    static func setLink(
        catalogId: String,
        token: ApplicationToken,
        displayName: String? = nil,
        iconURL: String? = nil
    ) {
        guard let data = AppRestrictTokenCodec.encode(token) else { return }
        var list = links.filter { $0.tokenData != data && $0.catalogId != catalogId }
        list.append(AppRestrictLinkRecord(
            catalogId: catalogId,
            tokenData: data,
            displayName: displayName,
            iconURL: iconURL
        ))
        links = list
    }

    static func removeLink(for token: ApplicationToken) {
        guard let data = AppRestrictTokenCodec.encode(token) else { return }
        links = links.filter { $0.tokenData != data }
    }

    static func applyShield(for tokens: Set<ApplicationToken>) {
        let store = AppRestrictShared.makeStore()
        if tokens.isEmpty {
            store.clearAllSettings()
        } else {
            store.shield.applications = tokens
        }
    }

    static func clearShield() {
        AppRestrictShared.makeStore().clearAllSettings()
    }

    static func loadShieldImage() -> UIImage? {
        let config = shieldConfig
        switch config.imageSource {
        case .album:
            if let url = AppRestrictShared.customImageURL,
               let data = try? Data(contentsOf: url),
               let image = UIImage(data: data) {
                return image
            }
            fallthrough
        case .presetDefault:
            return UIImage(named: "AppRestrict/shield_preset_default")
                ?? UIImage(systemName: "lock.shield.fill")
        case .presetFocus:
            return UIImage(named: "AppRestrict/shield_preset_focus")
                ?? UIImage(systemName: "brain.head.profile")
        case .presetCalm:
            return UIImage(named: "AppRestrict/shield_preset_calm")
                ?? UIImage(systemName: "leaf.fill")
        }
    }

    static func saveCustomImage(_ image: UIImage) -> Bool {
        guard let url = AppRestrictShared.customImageURL else { return false }
        let resized = image.appRestrictResized(maxSide: 720)
        guard let data = resized.jpegData(compressionQuality: 0.82) else { return false }
        do {
            try data.write(to: url, options: .atomic)
            return true
        } catch {
            return false
        }
    }
}

private extension UIImage {
    func appRestrictResized(maxSide: CGFloat) -> UIImage {
        let maxCurrent = max(size.width, size.height)
        guard maxCurrent > maxSide, maxCurrent > 0 else { return self }
        let scale = maxSide / maxCurrent
        let newSize = CGSize(width: size.width * scale, height: size.height * scale)
        let renderer = UIGraphicsImageRenderer(size: newSize)
        return renderer.image { _ in
            draw(in: CGRect(origin: .zero, size: newSize))
        }
    }
}