import LChatCore
import SwiftUI

// 🤖 Spaces ▸ Add from Link…: paste any Eleven invite link and the space joins
// this Mac NATIVELY — SpaceClaim handles all three link shapes (member/setup
// invites, DM invites, add-device links) with no webview; the secret in the
// #fragment never reaches any server. addInstance persists the identity in
// the Keychain, selects the space, and pushes it to the member's Eleven
// account (home vault), so it follows them to every signed-in device.
struct AddFromLinkSheet: View {
    @EnvironmentObject var app: MacAppState
    @Environment(\.dismiss) private var dismiss
    @State private var link = ""
    @State private var busy = false
    @State private var error: String?
    @State private var hint: String?

    /// The browser handoff's pre-fill (onOpenURL stashes the validated link;
    /// see LChatMacApp): consumed once, so a later manual open starts blank.
    /// The locked pane's rungs stash contextual guidance the same way.
    private func consumePendingLink() {
        if let pending = app.pendingAddLink {
            link = pending
            app.pendingAddLink = nil
        }
        if let h = app.addFromLinkHint {
            hint = h
            app.addFromLinkHint = nil
        }
    }

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Add a space from a link")
                .font(.headline)
            Text(hint ?? "Paste an invite link — the space joins this Mac and syncs to your Eleven account.")
                .font(.callout)
                .foregroundStyle(.secondary)
                .fixedSize(horizontal: false, vertical: true)
            TextField("https://…/join/…", text: $link)
                .textFieldStyle(.roundedBorder)
                .disabled(busy)
                .onSubmit(add)
            if let error {
                Text(error)
                    .font(.footnote)
                    .foregroundStyle(.red)
                    .fixedSize(horizontal: false, vertical: true)
            }
            HStack {
                Button("Cancel") { dismiss() }
                    .keyboardShortcut(.cancelAction)
                    .disabled(busy)
                Spacer()
                Button {
                    add()
                } label: {
                    HStack(spacing: 6) {
                        if busy { ProgressView().controlSize(.small) }
                        Text(busy ? "Joining…" : "Add Space")
                    }
                }
                .buttonStyle(.borderedProminent)
                .keyboardShortcut(.defaultAction)
                .disabled(busy || parseJoinLink(link.trimmingCharacters(in: .whitespacesAndNewlines)) == nil)
            }
        }
        .padding(20)
        .frame(width: 440)
        .onAppear(perform: consumePendingLink)
        // A handoff can land while the sheet is already up (a second click
        // in the browser) — take the newest link in place.
        .onChange(of: app.pendingAddLink) { _, pending in
            if pending != nil, !busy { consumePendingLink() }
        }
    }

    private func add() {
        let trimmed = link.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !busy, parseJoinLink(trimmed) != nil else {
            if !trimmed.isEmpty { error = "That doesn't look like an Eleven invite link." }
            return
        }
        busy = true
        error = nil
        Task { @MainActor in
            do {
                // Carry the name you already go by; an add-device link's own
                // "~name" (or "Me") wins inside the claim when this is empty.
                let screenName = app.instancesInRailOrder().first(where: { !$0.isArchived })?.screenName
                    ?? app.instances.first?.screenName ?? ""
                let inst = try await SpaceClaim.claim(setupLink: trimmed, screenName: screenName)
                app.addInstance(inst) // Keychain + rail + select + vault push
                dismiss()
            } catch {
                self.error = (error as? LocalizedError)?.errorDescription
                    ?? "Couldn't add that space."
                busy = false
            }
        }
    }
}