import ClawdisKit
import Foundation
import Network
import Observation
import SwiftUI
import UIKit

@MainActor
@Observable
final class BridgeConnectionController {
    private(set) var bridges: [BridgeDiscoveryModel.DiscoveredBridge] = []
    private(set) var discoveryStatusText: String = "Idle"
    private(set) var discoveryDebugLog: [BridgeDiscoveryModel.DebugLogEntry] = []

    private let discovery = BridgeDiscoveryModel()
    private weak var appModel: NodeAppModel?
    private var didAutoConnect = false
    private var seenStableIDs = Set<String>()

    init(appModel: NodeAppModel, startDiscovery: Bool = true) {
        self.appModel = appModel

        BridgeSettingsStore.bootstrapPersistence()
        let defaults = UserDefaults.standard
        self.discovery.setDebugLoggingEnabled(defaults.bool(forKey: "bridge.discovery.debugLogs"))

        self.updateFromDiscovery()
        self.observeDiscovery()

        if startDiscovery {
            self.discovery.start()
        }
    }

    func setDiscoveryDebugLoggingEnabled(_ enabled: Bool) {
        self.discovery.setDebugLoggingEnabled(enabled)
    }

    func setScenePhase(_ phase: ScenePhase) {
        switch phase {
        case .background:
            self.discovery.stop()
        case .active, .inactive:
            self.discovery.start()
        @unknown default:
            self.discovery.start()
        }
    }

    private func updateFromDiscovery() {
        let newBridges = self.discovery.bridges
        self.bridges = newBridges
        self.discoveryStatusText = self.discovery.statusText
        self.discoveryDebugLog = self.discovery.debugLog
        self.updateLastDiscoveredBridge(from: newBridges)
        self.maybeAutoConnect()
    }

    private func observeDiscovery() {
        withObservationTracking {
            _ = self.discovery.bridges
            _ = self.discovery.statusText
            _ = self.discovery.debugLog
        } onChange: { [weak self] in
            Task { @MainActor in
                guard let self else { return }
                self.updateFromDiscovery()
                self.observeDiscovery()
            }
        }
    }

    private func maybeAutoConnect() {
        guard !self.didAutoConnect else { return }
        guard let appModel = self.appModel else { return }
        guard appModel.bridgeServerName == nil else { return }

        let defaults = UserDefaults.standard
        let manualEnabled = defaults.bool(forKey: "bridge.manual.enabled")

        let instanceId = defaults.string(forKey: "node.instanceId")?
            .trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        guard !instanceId.isEmpty else { return }

        let token = KeychainStore.loadString(
            service: "com.steipete.clawdis.bridge",
            account: "bridge-token.\(instanceId)")?
            .trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        guard !token.isEmpty else { return }

        if manualEnabled {
            let manualHost = defaults.string(forKey: "bridge.manual.host")?
                .trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
            guard !manualHost.isEmpty else { return }

            let manualPort = defaults.integer(forKey: "bridge.manual.port")
            let resolvedPort = manualPort > 0 ? manualPort : 18790
            guard let port = NWEndpoint.Port(rawValue: UInt16(resolvedPort)) else { return }

            self.didAutoConnect = true
            appModel.connectToBridge(
                endpoint: .hostPort(host: NWEndpoint.Host(manualHost), port: port),
                hello: self.makeHello(token: token))
            return
        }

        let targetStableID = defaults.string(forKey: "bridge.lastDiscoveredStableID")?
            .trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        guard !targetStableID.isEmpty else { return }

        guard let target = self.bridges.first(where: { $0.stableID == targetStableID }) else { return }

        self.didAutoConnect = true
        appModel.connectToBridge(endpoint: target.endpoint, hello: self.makeHello(token: token))
    }

    private func updateLastDiscoveredBridge(from bridges: [BridgeDiscoveryModel.DiscoveredBridge]) {
        let newlyDiscovered = bridges.filter { self.seenStableIDs.insert($0.stableID).inserted }
        guard let last = newlyDiscovered.last else { return }

        UserDefaults.standard.set(last.stableID, forKey: "bridge.lastDiscoveredStableID")
        BridgeSettingsStore.saveLastDiscoveredBridgeStableID(last.stableID)
    }

    private func makeHello(token: String) -> BridgeHello {
        let defaults = UserDefaults.standard
        let nodeId = defaults.string(forKey: "node.instanceId") ?? "ios-node"
        let displayName = defaults.string(forKey: "node.displayName") ?? "iOS Node"

        return BridgeHello(
            nodeId: nodeId,
            displayName: displayName,
            token: token,
            platform: self.platformString(),
            version: self.appVersion(),
            deviceFamily: self.deviceFamily(),
            modelIdentifier: self.modelIdentifier())
    }

    private func platformString() -> String {
        let v = ProcessInfo.processInfo.operatingSystemVersion
        let name: String
        switch UIDevice.current.userInterfaceIdiom {
        case .pad:
            name = "iPadOS"
        case .phone:
            name = "iOS"
        default:
            name = "iOS"
        }
        return "\(name) \(v.majorVersion).\(v.minorVersion).\(v.patchVersion)"
    }

    private func deviceFamily() -> String {
        switch UIDevice.current.userInterfaceIdiom {
        case .pad:
            return "iPad"
        case .phone:
            return "iPhone"
        default:
            return "iOS"
        }
    }

    private func modelIdentifier() -> String {
        var systemInfo = utsname()
        uname(&systemInfo)
        let machine = withUnsafeBytes(of: &systemInfo.machine) { ptr in
            String(decoding: ptr.prefix { $0 != 0 }, as: UTF8.self)
        }
        return machine.isEmpty ? "unknown" : machine
    }

    private func appVersion() -> String {
        Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String ?? "dev"
    }
}