import LChatCore
import SwiftUI

// Start a new chat, iMessage-style: the sheet lists people — tap one and the DM
// starts immediately (the server dedupes, so an existing DM just opens). "New
// group" pushes the multi-select flow. Agent helpers get their own section with
// a BOT badge, mirroring the web picker. All key wrapping happens natively in
// ThreadStore.createChat.
struct NewChatView: View {
    @ObservedObject var store: ThreadStore
    @Environment(\.dismiss) private var dismiss
    let onCreated: (String) -> Void

    @State private var busyWith: String? // user id of the DM being created ("admin" = the Admin row)
    @State private var error: String?
    @State private var search = ""

    private var query: String { search.trimmingCharacters(in: .whitespaces) }
    private var others: [RosterEntry] { store.roster.filter { $0.user_id != store.myUserId } }
    private var people: [RosterEntry] { store.rosterMatches(others.filter { !$0.isAgent }, query) }
    // Bots off empties the Helpers section (matching the web picker) — existing
    // bot DMs stay in the sidebar; only starting new ones hides.
    private var helpers: [RosterEntry] {
        store.botsEnabled ? store.rosterMatches(others.filter { $0.isAgent }, query) : []
    }
    // Personal apps from the registry (places ∋ "you", listed) — the web
    // picker's Apps section, searchable by title like people are (Mac's
    // NewChatPopover does the same). Hidden entirely when apps are off.
    private var visibleApps: [AppManifest] {
        guard store.appsEnabled else { return [] }
        let apps = store.registry.personalApps
        return query.isEmpty ? apps
            : apps.filter { $0.title.localizedCaseInsensitiveContains(query) }
    }

    var body: some View {
        NavigationStack {
            List {
                // The action rows step aside while a query is live — search
                // results are people, not actions (clear the field to get
                // them back). The web keeps its equivalents in the sheet
                // header, so they never compete with matches there either.
                if query.isEmpty {
                    Section {
                        NavigationLink {
                            NewGroupView(store: store, onCreated: finish)
                        } label: {
                            Label {
                                Text("New group").font(.body.weight(.medium))
                            } icon: {
                                Image(systemName: "person.3.fill")
                                    .foregroundStyle(Color.accentColor)
                            }
                        }
                        // Bring someone new onto the server (if the admin allows
                        // member invites — the server says no otherwise).
                        NavigationLink {
                            InviteSomeoneView(store: store) { _ in dismiss() }
                        } label: {
                            Label {
                                Text("Invite someone").font(.body.weight(.medium))
                            } icon: {
                                Image(systemName: "person.badge.plus")
                                    .foregroundStyle(Color.accentColor)
                            }
                        }
                        // The community directory: open groups anyone can join.
                        NavigationLink {
                            DiscoverGroupsView(store: store, onOpen: finish)
                        } label: {
                            Label {
                                Text("Discover groups").font(.body.weight(.medium))
                            } icon: {
                                Image(systemName: "safari")
                                    .foregroundStyle(Color.accentColor)
                            }
                        }
                        // The Admin app, admins only (the roster carries our role; the
                        // server re-checks it) — same open-the-app-thread action as the
                        // web picker's Apps row, so /admin isn't the only way in.
                        if store.isAdmin {
                            Button { openAdmin() } label: {
                                HStack {
                                    Label {
                                        Text("Admin").font(.body.weight(.medium))
                                    } icon: {
                                        Image(systemName: "gearshape")
                                            .foregroundStyle(Color.accentColor)
                                    }
                                    Spacer()
                                    if busyWith == "admin" { ProgressView() }
                                }
                                .contentShape(Rectangle())
                            }
                            .buttonStyle(.plain)
                            .disabled(busyWith != nil)
                            .accessibilityLabel("Admin")
                            .accessibilityHint("Opens this space's admin panel")
                        }
                    }
                }

                if others.isEmpty {
                    Section {
                        Text("No one else has joined this chat yet.")
                            .foregroundStyle(.secondary)
                    }
                } else if !query.isEmpty && people.isEmpty && helpers.isEmpty && visibleApps.isEmpty {
                    Section {
                        Text("No matches.")
                            .foregroundStyle(.secondary)
                    }
                }
                if !people.isEmpty {
                    Section("People") {
                        ForEach(people, id: \.user_id) { person in personRow(person) }
                    }
                }
                if !helpers.isEmpty {
                    Section("Helpers") {
                        ForEach(helpers, id: \.user_id) { person in personRow(person) }
                    }
                }
                if !visibleApps.isEmpty {
                    Section("Apps") {
                        ForEach(visibleApps) { app in appRow(app) }
                    }
                }
                if let error {
                    Section { Text(error).foregroundStyle(.red) }
                }
            }
            .navigationTitle("New chat")
            .navigationBarTitleDisplayMode(.inline)
            // Always-visible, like the web picker's Search field — hiding it
            // behind a pull-down would read as "no way to filter" all over again.
            .searchable(text: $search, placement: .navigationBarDrawer(displayMode: .always),
                        prompt: "Search")
            // Return opens the top match, same as Enter on the web — but only
            // mid-query: a stray Search tap on an empty field shouldn't start
            // a DM with whoever happens to sort first.
            .onSubmit(of: .search) {
                guard !query.isEmpty, busyWith == nil else { return }
                if let first = people.first ?? helpers.first { startDM(first) }
            }
            .toolbar {
                ToolbarItem(placement: .cancellationAction) { Button("Cancel") { dismiss() } }
            }
        }
    }

    private func personRow(_ person: RosterEntry) -> some View {
        Button { startDM(person) } label: {
            HStack(spacing: 12) {
                // Nickname-resolved, like every other member list — the filter
                // matches this name, so the row must show it too.
                Avatar(name: store.displayName(for: person), size: 36,
                       source: store.avatarSource(for: person))
                Text(store.displayName(for: person)).foregroundStyle(.primary)
                if person.isAgent { BotBadge() }
                Spacer()
                if busyWith == person.user_id { ProgressView() }
            }
            // A .plain button only hit-tests its label's opaque content — the
            // Spacer and row padding were dead zones. Make the whole row tappable.
            .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .disabled(busyWith != nil)
    }

    private func startDM(_ person: RosterEntry) {
        busyWith = person.user_id
        error = nil
        Task {
            let id = await store.createChat(memberIDs: [person.user_id], groupName: nil)
            busyWith = nil
            if let id { finish(id) } else { error = store.loadError ?? "Couldn't start the chat." }
        }
    }

    // A personal app row: open (creating on first use) its app-thread and
    // dismiss into it — the same land-in-the-thread shape as picking a person.
    private func appRow(_ app: AppManifest) -> some View {
        Button {
            busyWith = app.name
            error = nil
            Task {
                let id = await store.openOrCreateAppThread(app: app.name, title: app.title)
                busyWith = nil
                if let id { finish(id) } else { error = store.loadError ?? "Couldn't open \(app.title)." }
            }
        } label: {
            HStack(spacing: 12) {
                Text(app.glyph)
                    .font(.system(size: 17))
                    .frame(width: 36, height: 36)
                    .background(Circle().fill(.primary.opacity(0.06)))
                VStack(alignment: .leading, spacing: 1) {
                    Text(app.title).foregroundStyle(.primary)
                    if let blurb = app.blurb, !blurb.isEmpty {
                        Text(blurb).font(.footnote).foregroundStyle(.secondary).lineLimit(1)
                    }
                }
                Spacer()
                if busyWith == app.name { ProgressView() }
            }
            .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .disabled(busyWith != nil)
        .accessibilityLabel(app.title)
        .accessibilityHint("Opens the \(app.title) app")
    }

    // Open (creating on first use) the Admin app-thread, then dismiss into it —
    // the same land-in-the-thread shape as picking a person.
    private func openAdmin() {
        busyWith = "admin" // an app id can't collide with a user id here
        error = nil
        Task {
            let id = await store.openOrCreateAppThread(app: "admin", title: "Admin")
            busyWith = nil
            if let id { finish(id) } else { error = store.loadError ?? "Couldn't open Admin." }
        }
    }

    private func finish(_ id: String) {
        onCreated(id)
        dismiss()
    }
}

// The multi-select group flow, pushed from NewChatView.
struct NewGroupView: View {
    @ObservedObject var store: ThreadStore
    let onCreated: (String) -> Void

    @State private var selected: Set<String> = []
    @State private var selectedApps: Set<String> = []
    @State private var groupName = ""
    @State private var openGroup = false
    @State private var busy = false
    @State private var error: String?
    @State private var search = ""

    private var query: String { search.trimmingCharacters(in: .whitespaces) }
    // Bots off drops agents from the member picker, same as the web's
    // add-to-group sheet (adding a bot to a group is starting new bot use).
    private var others: [RosterEntry] {
        store.rosterMatches(store.roster.filter {
            $0.user_id != store.myUserId && (store.botsEnabled || !$0.isAgent)
        }, query)
    }

    var body: some View {
        Form {
            Section("Group name") {
                TextField("Optional", text: $groupName)
                    .autocorrectionDisabled()
            }
            // Open community group — offered only once the instance key is
            // here (it carries the group key to future joiners), matching the
            // web sheet and how photos wait on the same key.
            if store.instanceKey() != nil {
                Section {
                    Toggle("Open group", isOn: $openGroup)
                } footer: {
                    Text("Anyone in this space can find it under Discover and join.")
                }
            }
            Section(header: Text(selected.isEmpty ? "Add people" : "\(selected.count) selected")) {
                if others.isEmpty && !query.isEmpty {
                    Text("No matches.").foregroundStyle(.secondary)
                }
                ForEach(others, id: \.user_id) { person in
                    Button { toggle(person.user_id) } label: {
                        HStack(spacing: 12) {
                            Avatar(name: store.displayName(for: person), size: 32,
                                   source: store.avatarSource(for: person))
                            Text(store.displayName(for: person)).foregroundStyle(.primary)
                            if person.isAgent { BotBadge() }
                            Spacer()
                            if selected.contains(person.user_id) {
                                Image(systemName: "checkmark.circle.fill").foregroundStyle(.tint)
                            } else {
                                Image(systemName: "circle").foregroundStyle(.tertiary)
                            }
                        }
                        // Same as personRow: without an explicit content shape only
                        // the glyphs hit-test, so selecting felt like tapping radio
                        // buttons. The whole row should toggle.
                        .contentShape(Rectangle())
                    }
                    .buttonStyle(.plain)
                }
            }
            // Shared apps, picked at birth — each one lands as a groupapps.add
            // in the fresh log, so every member folds the same list (the same
            // apps you could add later from ⋯ → Manage Apps). Hidden entirely
            // when the admin turned apps off.
            if store.appsEnabled {
                Section {
                    // Every group-capable app from the registry (places ∋
                    // "chat", listed) — the same list the ⋮ → Manage Apps
                    // sheet offers, custom and member apps included.
                    ForEach(store.registry.groupApps) { app in
                        Button { toggleApp(app.name) } label: {
                            HStack(spacing: 12) {
                                Image(systemName: AppIdentity.symbol(for: app.name) ?? "square.grid.2x2")
                                    .font(.system(size: 14, weight: .medium))
                                    .foregroundStyle(.primary)
                                    .frame(width: 32, height: 32)
                                    .background(Circle().fill(.primary.opacity(0.06)))
                                Text(app.title).foregroundStyle(.primary)
                                Spacer()
                                if selectedApps.contains(app.name) {
                                    Image(systemName: "checkmark.circle.fill").foregroundStyle(.tint)
                                } else {
                                    Image(systemName: "circle").foregroundStyle(.tertiary)
                                }
                            }
                            .contentShape(Rectangle())
                        }
                        .buttonStyle(.plain)
                    }
                } header: {
                    Text("Apps")
                } footer: {
                    Text("Apps are shared with everyone in the group — one list, one set of data.")
                }
            }
            if let error {
                Section { Text(error).foregroundStyle(.red) }
            }
        }
        .navigationTitle("New group")
        .navigationBarTitleDisplayMode(.inline)
        .searchable(text: $search, placement: .navigationBarDrawer(displayMode: .always),
                    prompt: "Search")
        .toolbar {
            ToolbarItem(placement: .confirmationAction) {
                if busy { ProgressView() }
                else {
                    // An open group may start with just its creator — others
                    // find it in Discover; a closed group still needs people.
                    Button("Create") { create() }
                        .disabled(selected.isEmpty && !openGroup)
                }
            }
        }
    }

    private func toggle(_ id: String) {
        if selected.contains(id) { selected.remove(id) } else { selected.insert(id) }
    }

    private func toggleApp(_ id: String) {
        if selectedApps.contains(id) { selectedApps.remove(id) } else { selectedApps.insert(id) }
    }

    private func create() {
        busy = true
        error = nil
        Task {
            let id = await store.createChat(memberIDs: Array(selected), groupName: groupName,
                                            group: true, apps: Array(selectedApps).sorted(),
                                            openGroup: openGroup)
            busy = false
            if let id { onCreated(id) } else { error = store.loadError ?? "Couldn't create the group." }
        }
    }
}

// The "BOT" tag next to agent helpers — mirrors the web picker's badge.
struct BotBadge: View {
    var body: some View {
        Text("BOT")
            .font(.caption2.weight(.bold))
            .padding(.horizontal, 5)
            .padding(.vertical, 2)
            .background(Color.accentColor.opacity(0.15), in: RoundedRectangle(cornerRadius: 4))
            .foregroundStyle(Color.accentColor)
    }
}