import SwiftUI
import ServiceManagement

struct SettingsView: View {
    @EnvironmentObject private var automation: BackgroundSyncManager
    @AppStorage("defaultSSHUsername") private var defaultSSHUsername = NSUserName()
    @AppStorage("defaultSSHKeyPath") private var defaultSSHKeyPath = ""
    @AppStorage("defaultSSHPort") private var defaultSSHPort = 22
    @AppStorage("defaultRemoteHost") private var defaultRemoteHost = ""
    @AppStorage("backgroundSchedulesEnabled") private var backgroundSchedulesEnabled = true
    @AppStorage("fileWatchingEnabled") private var fileWatchingEnabled = true
    @AppStorage("defaultWatchDebounceSeconds") private var defaultWatchDebounceSeconds = 3
    @AppStorage("historyRetentionDays") private var historyRetentionDays = 90
    @State private var launchAtLogin = false
    @State private var launchError: String?

    var body: some View {
        TabView {
            Form {
                Section("Default SSH Connection") {
                    TextField("Username", text: $defaultSSHUsername, prompt: Text(NSUserName()))
                    TextField("Default host", text: $defaultRemoteHost, prompt: Text("server.local"))
                    Stepper("SSH port: \(defaultSSHPort)", value: $defaultSSHPort, in: 1...65535)

                    HStack {
                        TextField("Private SSH key", text: $defaultSSHKeyPath, prompt: Text("~/.ssh/id_ed25519"))
                        Button("Choose…") {
                            if let selected = FilePicker.chooseFile() { defaultSSHKeyPath = selected }
                        }
                    }

                    Label("Authentication uses an SSH private key or your macOS SSH agent. Passwords are intentionally not stored or passed on the command line.", systemImage: "lock.shield")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }

                Section("New Jobs") {
                    Text("New SSH jobs use these values as defaults and can override them independently.")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }
            }
            .formStyle(.grouped)
            .tabItem { Label("Connections", systemImage: "network") }

            Form {
                Section("Background Scheduling") {
                    Toggle("Run scheduled jobs", isOn: $backgroundSchedulesEnabled)
                    Toggle("Launch Rsync Manager at login", isOn: Binding(
                        get: { launchAtLogin },
                        set: { setLaunchAtLogin($0) }
                    ))
                    HStack {
                        Label("Configured jobs", systemImage: "calendar.badge.clock")
                        Spacer()
                        Text("\(automation.scheduledJobCount)")
                            .foregroundStyle(.secondary)
                    }
                    Text("Scheduled jobs run without opening a modal and are written to History. Rsync Manager continues processing them while its window is hidden, minimised or closed, provided the application itself remains running.")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }

                Section("History & Privacy") {
                    Stepper("Keep run history for \(historyRetentionDays) days", value: $historyRetentionDays, in: 7...3650, step: 7)
                    Text("Run output is sanitised, ANSI control sequences are removed, and individual stdout/stderr logs are capped at approximately 2 MB before storage.")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }

                Section("File Watching") {
                    Toggle("Watch enabled jobs for changes", isOn: $fileWatchingEnabled)
                    Stepper("Default debounce: \(defaultWatchDebounceSeconds) seconds", value: $defaultWatchDebounceSeconds, in: 1...60)
                    HStack {
                        Label("Watched jobs", systemImage: "eye.fill")
                        Spacer()
                        Text("\(automation.watchedJobCount)")
                            .foregroundStyle(.secondary)
                    }
                    Text("Rsync Manager uses macOS FSEvents, so watched trees do not need to be repeatedly scanned. A short debounce combines rapid saves into a single sync.")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }
            }
            .formStyle(.grouped)
            .tabItem { Label("Automation", systemImage: "calendar.badge.clock") }

            Form {
                Section("Rsync") {
                    LabeledContent("Detected executable", value: RsyncLocator.locate())
                    LabeledContent("Executable validation", value: RsyncLocator.isTrustedExecutableCandidate(RsyncLocator.locate()) ? "Passed" : "Failed")
                    Text("Only executable regular-file rsync candidates are accepted. Symlinks are resolved before validation.")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }

                Section("Security") {
                    LabeledContent("SSH mode", value: "Batch / key or agent")
                    LabeledContent("Host-key verification", value: "System default")
                    Text("SSH connections use BatchMode, connection timeouts and keepalive limits. Rsync Manager never disables SSH host-key verification.")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }

                Section("Application") {
                    LabeledContent("Bundle identifier", value: Bundle.main.bundleIdentifier ?? "net.absdev.RsyncManager")
                    LabeledContent("Version", value: Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String ?? "1.0")
                    LabeledContent("Background service", value: automation.activity.title)
                }
            }
            .formStyle(.grouped)
            .tabItem { Label("General", systemImage: "gearshape") }
        }
        .frame(width: 650, height: 455)
        .onAppear {
            KeychainStore.delete("defaultSSHPassword")
            launchAtLogin = SMAppService.mainApp.status == .enabled
        }
        .onChange(of: backgroundSchedulesEnabled) { _, _ in automation.refreshConfiguration() }
        .onChange(of: fileWatchingEnabled) { _, _ in automation.refreshConfiguration() }
        .alert("Launch at Login", isPresented: Binding(
            get: { launchError != nil },
            set: { if !$0 { launchError = nil } }
        )) {
            Button("OK", role: .cancel) { launchError = nil }
        } message: {
            Text(launchError ?? "Unable to change the login item setting.")
        }
    }

    private func setLaunchAtLogin(_ enabled: Bool) {
        do {
            if enabled {
                try SMAppService.mainApp.register()
            } else {
                try SMAppService.mainApp.unregister()
            }
            launchAtLogin = SMAppService.mainApp.status == .enabled
        } catch {
            launchAtLogin = SMAppService.mainApp.status == .enabled
            launchError = error.localizedDescription
        }
    }
}