import AppKit
import SwiftUI
import os

// MARK: - Focused values

/// The frontmost board window's **identity**, published beside its store by `BoardWindowHost`.
///
/// `FocusedBoardStoreKey` answers "which board is in front"; this answers "which *window*", which is
/// a different question and the one File ▸ Duplicate has to ask: the flush that precedes a copy is
/// keyed on the window's session, not on the store (`AppModel.flushPendingWork(for:)`).
struct FocusedBoardWindowRefKey: FocusedValueKey {
    typealias Value = BoardWindowRef
}

/// The welcome window's selected recents row — File ▸ Reveal in Finder's welcome scope.
struct FocusedWelcomeSelectionKey: FocusedValueKey {
    typealias Value = WelcomeRow
}

extension FocusedValues {
    var boardWindowRef: BoardWindowRef? {
        get { self[FocusedBoardWindowRefKey.self] }
        set { self[FocusedBoardWindowRefKey.self] = newValue }
    }

    var welcomeSelection: WelcomeRow? {
        get { self[FocusedWelcomeSelectionKey.self] }
        set { self[FocusedWelcomeSelectionKey.self] = newValue }
    }
}

// MARK: - New Board

/// File ▸ New Board… (⌥⌘N) — the template chooser's entry point (11-command-nexus.md;
/// 09-templates.md).
///
/// **⌥⌘N, not ⌘N**: ⌘N is New *Card*, which is the command a board window user reaches for a hundred
/// times a day, so the rarer creation wears the modifier. Available everywhere — a new board needs
/// no board in front, and the welcome window's own button is this item's twin.
struct NewBoardCommand: View {

    let appModel: AppModel

    var body: some View {
        Button("New Board…") {
            appModel.showTemplateChooser()
        }
        .keyboardShortcut("n", modifiers: [.option, .command])
    }
}

// MARK: - Open Recent

/// File ▸ Open Recent ▸ (11-command-nexus.md: "Everywhere; reads the board registry").
///
/// The registry, rendered as a menu — same rows as the welcome list, through the same derivation, so
/// the two can never disagree about a board's name or about whether it can be opened. An
/// unavailable board is **listed and disabled** rather than hidden, which is the recents row's own
/// posture (02 § Graceful orphaning) applied to a menu: a board that has gone missing is information,
/// and a menu that quietly shortened itself would be the app forgetting on the user's behalf.
///
/// Clear Menu sits at the bottom, where Finder puts it. See `AppModel.clearRecents` for the
/// equivalence it rests on — the registry *is* this menu, so clearing the menu clears the registry.
struct OpenRecentMenu: View {

    let appModel: AppModel

    /// The failures are deliberately not joined in here: a menu item has no room for fail-fast's
    /// specifics, and a board that failed to open is still a board the user may want to try again.
    /// The failure's surface is the welcome row (02 § Launch and window lifecycle).
    private var rows: [WelcomeRow] {
        WelcomeRow.derive(recents: appModel.recents, failures: []).rows
    }

    var body: some View {
        let rows = self.rows

        Menu("Open Recent") {
            ForEach(rows) { row in
                Button(row.displayName) {
                    guard let url = row.url else { return }
                    appModel.openBoard(at: url)
                }
                .disabled(!row.canOpen)
            }

            if !rows.isEmpty {
                Divider()
            }

            Button("Clear Menu") {
                appModel.clearRecents()
            }
            .disabled(rows.isEmpty)
        }
    }
}

// MARK: - Duplicate

/// File ▸ Duplicate (⇧⌘S) — **the board**, never the selection (11-command-nexus.md, 03-board-ui.md
/// § Welcome screen & templates).
///
/// ### What it does, in the order 03 fixes
///
/// 1. **The flush first** — "The copy is preceded by the close flush ... so neither the tree nor the
///    copied history misses pending work". Not a *close*: 09-templates.md states the rule with its
///    exception attached ("sessions staying open"), and 03 is explicit that "the original stays open
///    too". `AppModel.flushPendingWork(for:)` is that step of the sequence, run on its own.
/// 2. **The copy** — `BoardDuplicator`, off the main actor so the spinner can spin.
/// 3. **The copy opens in its own board window** — "macOS Duplicate convention" — through the
///    ordinary open path, so it registers, bookmarks, and titles itself like any other board.
///
/// ### Validation
///
/// Board window only, so a welcome-selected recent can never be duplicated by accident — 03 says it
/// "never acts on a welcome-selected recent", and scoping the item to the focused board window is
/// how that is enforced rather than remembered.
///
/// **Disabled under the read-only lock in every state** (03: "the flush can't run and the sibling
/// destination shares the board's fate"). It uses `acceptsBoardMutations`, which adds the
/// focused-inline-editor half of 04's rule to the lock 03 names — a deliberate reading rather than a
/// slip: an open title editor holds the one pending change no flush can reach, and a duplicate taken
/// mid-rename would be a fork missing the edit the user is in the middle of making.
struct DuplicateBoardCommand: View {

    let appModel: AppModel

    @FocusedValue(\.boardStore) private var store
    @FocusedValue(\.boardWindowRef) private var ref

    private static let logger = Logger(subsystem: "dev.rzen.indie.Kanban", category: "duplicate")

    var body: some View {
        Button("Duplicate") {
            duplicate()
        }
        .keyboardShortcut("s", modifiers: [.shift, .command])
        .disabled(!canDuplicate)
    }

    private var canDuplicate: Bool {
        guard let store, ref != nil else { return false }
        return store.acceptsBoardMutations
    }

    private func duplicate() {
        guard canDuplicate, let store, let ref else { return }
        let name = AppModel.displayName(of: store)
        let source = store.rootURL

        Task { @MainActor in
            // The in-progress row 02 § The banner surface names for "big-board Duplicate": info
            // tone, pinned, cleared on completion, swapped for the error row on failure.
            //
            // No Cancel yet. 02 promises one on copy-shaped work ("remove the partial copy, nothing
            // lost"), which needs a cooperatively cancellable copy and a cleanup of the partial
            // destination; `beginOperation`'s `cancel` slot is where it plugs in.
            let operation = store.banners.beginOperation(label: "Duplicating '\(name)'…")
            defer { store.banners.endOperation(operation) }

            await appModel.flushPendingWork(for: ref)

            do {
                // Off the main actor: the copy is real I/O on a board that may carry a large `.git`,
                // and a spinner drawn by a blocked main thread is a still picture. See
                // `BoardDuplicator` for why that is safe here.
                let copy = try await Task.detached(priority: .userInitiated) {
                    try BoardDuplicator.duplicate(boardAt: source, titled: name)
                }.value
                appModel.openBoard(at: copy)
            } catch let error as BoardWriteError {
                Self.logger.error("duplicate failed: \(error.description, privacy: .public)")
                store.banners.post(error)
            } catch {
                store.banners.post(BoardWriteError(
                    operation: .duplicateBoard(title: name),
                    path: source.path,
                    reason: .io(message: error.localizedDescription)
                ))
            }
        }
    }
}

// MARK: - Reveal in Finder

/// File ▸ Reveal in Finder — the welcome and board scopes (11-command-nexus.md: "Board window: the
/// selection's folder(s), or the board root with nothing selected; … welcome: the selected recent's
/// folder (disabled on unavailable rows) — the context-menu entry's required twin").
///
/// It is here because the welcome row's context menu is: 11 files the menu-bar item as that entry's
/// *required* twin, so shipping one without the other would leave the context menu as the only path
/// to a command — the thing 04's contract forbids.
///
/// **The board scope reveals either side of the trash boundary and ignores every lock.** Reveal "is
/// not edit-shaped and stays enabled on tombstoned selections" (04 ▸ The trash), and inspection is a
/// read, so neither the read-only lock nor the focused-editor rule applies — the same posture the
/// trash row's own Reveal takes. A selection whose ids resolve to no folders (one the next reload
/// will drop) disables rather than falling back to the root: revealing the wrong thing is worse
/// than nothing, and only a genuinely empty selection means "the board".
///
// m6-card-window: the item's third scope — the card's folder, or the selected attachment's file
// when the attachments section is focused — adds a focused value and a branch here; the two below
// do not move.
struct RevealInFinderCommand: View {

    @FocusedValue(\.boardStore) private var store
    @FocusedValue(\.welcomeSelection) private var selection

    var body: some View {
        Button("Reveal in Finder") {
            NSWorkspace.shared.activateFileViewerSelecting(urls)
        }
        .disabled(urls.isEmpty)
    }

    /// What the item would reveal, and therefore whether it is enabled — one answer for both, the
    /// codebase's usual shape. The board in front wins; the welcome branch stands when no board is.
    private var urls: [URL] {
        if let store {
            let ids = store.selection.ids
            guard !ids.isEmpty else { return [store.rootURL] }
            return TrashModel.paths(of: ids, on: store.selection.liveness, in: store.snapshot)
                .map { $0.folder(under: store.rootURL) }
        }
        guard let selection, selection.canReveal, let url = selection.url else { return [] }
        return [url]
    }
}