import Foundation
import Testing
@testable import Kanban

/// The card window's comments **handle** — the object every menu row, every pane view and the close
/// flush actually talk to (05-card-window.md ▸ The comments column).
///
/// What it owns is orderings and lifecycles, which is exactly the class of thing that looks right in
/// a running window and is wrong: the sweep-before-read at open, the saves-before-purge at close, a
/// session that must be dropped when its comment vanishes underneath it. So the seams are closures,
/// this suite fills them with a log, and the assertions are about *sequence*.
///
/// The bytes are `CommentWriteTests`'; the buffers are `CommentSessionTests`'; the pure layout is
/// `CardCommentsLayoutTests`'.

// MARK: - The log

/// Every seam a `CardComments` can reach, recorded in the order it was reached.
@MainActor
private final class CommentsSpy {
    enum Event: Equatable {
        case sweep
        case readThread
        case readDraft
        case purge
        case displace([String])
        case delete(String)
        case edit(String, String)
        case saveDraft(String)
        case post
        case importFiles([String], CommentTarget)
        case removeFile(String, CommentTarget)
    }

    private(set) var events: [Event] = []

    var thread: CommentThread = .empty
    var draft: CommentDraft?
    var deleteLands = true
    var editLands = true
    var postedID: ItemID? = ItemID(rawValue: CommentIdent.two)

    func install(on comments: CardComments) {
        comments.readThread = { [self] in events.append(.readThread); return thread }
        comments.readDraft = { [self] in events.append(.readDraft); return draft }
        comments.sweepTrashResidue = { [self] in events.append(.sweep) }
        comments.purgeTrash = { [self] in events.append(.purge) }
        comments.displaceSquatters = { [self] squatters in
            events.append(.displace(squatters.map(\.name)))
        }
        comments.deleteComment = { [self] id in
            events.append(.delete(id.rawValue))
            return deleteLands
        }
        comments.editComment = { [self] id, body in
            events.append(.edit(id.rawValue, body))
            return editLands
        }
        comments.importAttachments = { [self] urls, target in
            events.append(.importFiles(urls.map(\.lastPathComponent), target))
        }
        comments.removeAttachment = { [self] name, target in
            events.append(.removeFile(name, target))
        }
        comments.composer.save = { [self] text in
            events.append(.saveDraft(text))
            return .updated
        }
        comments.composer.post = { [self] in
            events.append(.post)
            return postedID
        }
    }
}

/// A comment value with only the fields this suite reads — the loader builds the real ones
/// (`CommentThreadTests`), and a thread assembled here is only ever a stand-in for one it produced.
private func comment(_ id: String, body: String = "text\n", attachments: [String] = []) -> Kanban.Comment {
    Kanban.Comment(
        id: ItemID(rawValue: id),
        schema: .valid(1),
        author: .missing,
        created: .missing,
        modified: .missing,
        modifiedBy: .missing,
        attachments: attachments,
        document: FrontmatterDocument(body: body)
    )
}

private func thread(_ comments: [Kanban.Comment], defects: [IntegrityRules.Defect] = []) -> CommentThread {
    CommentThread(comments: comments, strays: [], defects: defects, hasDraft: false)
}

@MainActor
private func makeComments(_ spy: CommentsSpy) -> CardComments {
    let comments = CardComments()
    comments.isEditable = true
    comments.cardFolder = URL(fileURLWithPath: "/board/lane/card", isDirectory: true)
    spy.install(on: comments)
    return comments
}

// MARK: - Opening

@MainActor
@Suite("Card comments ▸ opening")
struct CardCommentsOpenTests {

    @Test("The residue sweep runs before the thread read")
    func sweepPrecedesTheRead() {
        // The sweep *removes* folders, so a read taken before it would describe a
        // `comments/.trash/` that is about to stop existing (01-storage-format.md § Enhanced schema).
        let spy = CommentsSpy()
        let comments = makeComments(spy)

        comments.open()
        #expect(spy.events.prefix(2) == [.sweep, .readThread])
    }

    @Test("Opening reads the draft too — restore-on-reopen is just the read")
    func openRestoresTheDraft() {
        let spy = CommentsSpy()
        spy.draft = CommentDraft(body: "half a thought\n", attachments: ["shot.png"])
        let comments = makeComments(spy)

        comments.open()
        #expect(comments.composer.text == "half a thought\n")
        #expect(comments.composer.attachments == ["shot.png"])
        #expect(!comments.composer.isDirty)
    }

    @Test("A pane with no store reads nothing rather than showing an empty thread it invented")
    func noSeamsIsNoRead() {
        let comments = CardComments()
        comments.reload()
        #expect(comments.thread == .empty)
    }
}

// MARK: - Reloading

@MainActor
@Suite("Card comments ▸ the live reload")
struct CardCommentsReloadTests {

    @Test("A reload replaces the thread")
    func reloadReplacesTheThread() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        spy.thread = thread([comment(CommentIdent.one)])

        comments.reload()
        #expect(comments.thread.comments.map(\.id.rawValue) == [CommentIdent.one])
    }

    @Test("Claimed-name squatters the read found are routed to the displacement")
    func squattersAreDisplaced() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        spy.thread = thread([], defects: [.claimedNameSquatted(ClaimedNameSquatter(
            name: ".draft",
            found: .file,
            expected: .directory,
            location: .commentThread(cardPath: "lane/card")
        ))])

        comments.reload()
        #expect(spy.events.contains(.displace([".draft"])))
    }

    @Test("A clean read displaces nothing — no bracket for a thread with no work in it")
    func aCleanReadDisplacesNothing() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        spy.thread = thread([comment(CommentIdent.one)])

        comments.reload()
        #expect(!spy.events.contains { if case .displace = $0 { true } else { false } })
    }

    @Test("An open session follows disk while clean, and keeps its keystrokes while dirty")
    func theSessionObeysDirtyBufferWins() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        spy.thread = thread([comment(CommentIdent.one, body: "original\n")])
        comments.reload()
        comments.beginEdit(ItemID(rawValue: CommentIdent.one))

        spy.thread = thread([comment(CommentIdent.one, body: "an agent rewrote it\n")])
        comments.reload()
        #expect(comments.editing?.text == "an agent rewrote it\n")

        comments.editing?.edited("mine\n")
        spy.thread = thread([comment(CommentIdent.one, body: "and again\n")])
        comments.reload()
        #expect(comments.editing?.text == "mine\n")
    }

    @Test("A session whose comment vanished is dropped, with no error UI of its own")
    func aVanishedCommentDropsItsSession() {
        // 05 ▸ Deletion & lifecycle's "nowhere left to write", applied one level down: the store
        // answers `false`/`nil` for a target that is gone, and there is nothing here to tell the user
        // that `performWrite` has not already said.
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        spy.thread = thread([comment(CommentIdent.one)])
        comments.reload()
        comments.beginEdit(ItemID(rawValue: CommentIdent.one))
        #expect(comments.editing != nil)

        spy.thread = .empty
        comments.reload()
        #expect(comments.editing == nil)
    }
}

// MARK: - The inline session

@MainActor
@Suite("Card comments ▸ the inline edit session")
struct CardCommentsEditTests {

    private func opened(_ spy: CommentsSpy) -> CardComments {
        let comments = makeComments(spy)
        spy.thread = thread([
            comment(CommentIdent.one, body: "first\n"),
            comment(CommentIdent.two, body: "second\n")
        ])
        comments.reload()
        return comments
    }

    @Test("Edit opens a session over the comment's current body")
    func editOpensASession() {
        let spy = CommentsSpy()
        let comments = opened(spy)

        comments.beginEdit(ItemID(rawValue: CommentIdent.one))
        #expect(comments.editing?.commentID.rawValue == CommentIdent.one)
        #expect(comments.editing?.text == "first\n")
        #expect(comments.editing?.sessionStart == "first\n")
    }

    @Test("One session at a time — opening a second commits the first")
    func oneSessionAtATime() {
        let spy = CommentsSpy()
        let comments = opened(spy)

        comments.beginEdit(ItemID(rawValue: CommentIdent.one))
        comments.editing?.edited("first, revised\n")
        comments.beginEdit(ItemID(rawValue: CommentIdent.two))

        #expect(spy.events.contains(.edit(CommentIdent.one, "first, revised\n")),
                "the user asked to edit another comment — not to throw this one away")
        #expect(comments.editing?.commentID.rawValue == CommentIdent.two)
    }

    @Test("Re-editing the comment already open is a no-op, not a restarted session")
    func reEditingIsANoOp() {
        let spy = CommentsSpy()
        let comments = opened(spy)

        comments.beginEdit(ItemID(rawValue: CommentIdent.one))
        comments.editing?.edited("typed\n")
        comments.beginEdit(ItemID(rawValue: CommentIdent.one))

        #expect(comments.editing?.text == "typed\n", "a restart would lose the start-of-session bytes")
        #expect(comments.editing?.sessionStart == "first\n")
    }

    @Test("Save flushes and closes the session")
    func saveCommits() {
        let spy = CommentsSpy()
        let comments = opened(spy)

        comments.beginEdit(ItemID(rawValue: CommentIdent.one))
        comments.editing?.edited("revised\n")
        comments.commitEdit()

        #expect(spy.events.contains(.edit(CommentIdent.one, "revised\n")))
        #expect(comments.editing == nil)
    }

    @Test("Cancel writes the session-start bytes back and closes the session")
    func cancelReverts() {
        let spy = CommentsSpy()
        let comments = opened(spy)

        comments.beginEdit(ItemID(rawValue: CommentIdent.one))
        comments.editing?.edited("half a rewrite\n")
        comments.editing?.flush()
        comments.cancelEdit()

        #expect(spy.events.contains(.edit(CommentIdent.one, "first\n")))
        #expect(comments.editing == nil)
    }

    @Test("Under the read-only lock no session opens at all")
    func theLockRefusesASession() {
        let spy = CommentsSpy()
        let comments = opened(spy)
        comments.isEditable = false

        comments.beginEdit(ItemID(rawValue: CommentIdent.one))
        #expect(comments.editing == nil)
    }

    @Test("Editing a comment the read never found opens nothing")
    func editingAVanishedCommentOpensNothing() {
        let spy = CommentsSpy()
        let comments = opened(spy)

        comments.beginEdit(ItemID(rawValue: CommentIdent.three))
        #expect(comments.editing == nil)
    }
}

// MARK: - Delete

@MainActor
@Suite("Card comments ▸ delete")
struct CardCommentsDeleteTests {

    @Test("Delete is immediate — no confirm, and the store's own step")
    func deleteIsImmediate() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        spy.thread = thread([comment(CommentIdent.one)])
        comments.reload()

        comments.delete(ItemID(rawValue: CommentIdent.one))
        #expect(spy.events.contains(.delete(CommentIdent.one)))
    }

    @Test("Deleting the comment being edited commits the session first")
    func deleteCommitsTheOpenSession() {
        // The user's last keystrokes belong in the file that is about to move into
        // `comments/.trash/`, so an undo brings back what they wrote.
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        spy.thread = thread([comment(CommentIdent.one, body: "first\n")])
        comments.reload()
        comments.beginEdit(ItemID(rawValue: CommentIdent.one))
        comments.editing?.edited("last words\n")

        comments.delete(ItemID(rawValue: CommentIdent.one))

        let edit = spy.events.firstIndex(of: .edit(CommentIdent.one, "last words\n"))
        let delete = spy.events.firstIndex(of: .delete(CommentIdent.one))
        #expect(edit != nil)
        #expect(delete != nil)
        #expect((edit ?? 0) < (delete ?? 0))
        #expect(comments.editing == nil)
    }

    @Test("Under the read-only lock nothing is deleted")
    func theLockRefusesADelete() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        comments.isEditable = false

        comments.delete(ItemID(rawValue: CommentIdent.one))
        #expect(!spy.events.contains(.delete(CommentIdent.one)))
    }
}

// MARK: - Attachments on the authoring surfaces

@MainActor
@Suite("Card comments ▸ authoring attachments")
struct CardCommentsAttachmentTests {

    @Test("A drop on the composer imports into the draft; one on an inline session, into its comment")
    func importsAimAtTheirSurface() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        let file = URL(fileURLWithPath: "/tmp/shot.png")
        let id = ItemID(rawValue: CommentIdent.one)

        comments.importFiles([file], to: .draft)
        #expect(spy.events.contains(.importFiles(["shot.png"], .draft)))

        comments.importFiles([file], to: .comment(id))
        #expect(spy.events.contains(.importFiles(["shot.png"], .comment(id))))
    }

    @Test("An authoring chip's Remove aims at its own surface")
    func removesAimAtTheirSurface() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)

        comments.removeFile(named: "shot.png", from: .draft)
        #expect(spy.events.contains(.removeFile("shot.png", .draft)))
    }

    @Test("Under the read-only lock neither import nor remove happens")
    func theLockRefusesBoth() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        comments.isEditable = false

        comments.importFiles([URL(fileURLWithPath: "/tmp/shot.png")], to: .draft)
        comments.removeFile(named: "shot.png", from: .draft)
        #expect(spy.events.isEmpty)
    }

    @Test("A chip resolves against its own surface's attachments folder")
    func chipURLsResolve() throws {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        let id = ItemID(rawValue: CommentIdent.one)

        let draft = try #require(comments.attachmentURL("shot.png", in: .draft))
        #expect(draft.path.hasSuffix("/comments/.draft/attachments/shot.png"))

        let posted = try #require(comments.attachmentURL("shot.png", in: .comment(id)))
        #expect(posted.path.hasSuffix("/comments/\(CommentIdent.one)/attachments/shot.png"))
    }
}

// MARK: - The close flush

@MainActor
@Suite("Card comments ▸ the close flush")
struct CardCommentsCloseTests {

    @Test("Saves first, purge last")
    func savesPrecedeThePurge() {
        // The purge removes the folders a delete moved aside; running it before a session's save
        // could remove a folder that save was about to write into.
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        spy.thread = thread([comment(CommentIdent.one, body: "first\n")])
        comments.reload()
        comments.beginEdit(ItemID(rawValue: CommentIdent.one))
        comments.editing?.edited("mid-sentence\n")
        comments.composer.edited("a draft\n")

        comments.endSession()

        let edit = try? #require(spy.events.firstIndex(of: .edit(CommentIdent.one, "mid-sentence\n")))
        let draft = try? #require(spy.events.firstIndex(of: .saveDraft("a draft\n")))
        let purge = try? #require(spy.events.firstIndex(of: .purge))
        #expect((edit ?? 0) < (purge ?? 0))
        #expect((draft ?? 0) < (purge ?? 0))
    }

    @Test("The close flushes the session — it never reverts it")
    func theCloseIsNotACancel() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        spy.thread = thread([comment(CommentIdent.one, body: "first\n")])
        comments.reload()
        comments.beginEdit(ItemID(rawValue: CommentIdent.one))
        comments.editing?.edited("kept\n")

        comments.endSession()
        #expect(spy.events.contains(.edit(CommentIdent.one, "kept\n")))
        #expect(!spy.events.contains(.edit(CommentIdent.one, "first\n")), "a close is not an abandon")
    }

    @Test("Ending twice does the work once")
    func endingTwiceIsIdempotent() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        comments.composer.edited("a draft\n")

        comments.endSession()
        comments.endSession()

        #expect(spy.events.filter { $0 == .saveDraft("a draft\n") }.count == 1)
    }

    @Test("A clean pane still purges — the trash is the app's leftovers, not the user's work")
    func aCleanPaneStillPurges() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)

        comments.endSession()
        #expect(spy.events == [.purge])
    }
}

// MARK: - Unsaved content

@MainActor
@Suite("Card comments ▸ what counts as unsaved")
struct CardCommentsUnsavedTests {

    @Test("An inline edit session's dirty buffer counts")
    func theInlineSessionCounts() {
        let spy = CommentsSpy()
        let comments = makeComments(spy)
        spy.thread = thread([comment(CommentIdent.one, body: "first\n")])
        comments.reload()
        comments.beginEdit(ItemID(rawValue: CommentIdent.one))

        #expect(!comments.holdsUnsavedContent)
        comments.editing?.edited("typed\n")
        #expect(comments.holdsUnsavedContent)
    }

    @Test("The composer's draft deliberately does not")
    func theDraftDoesNotCount() {
        // "Close and quit just proceed — no DirtyBufferGuard, nothing to lose" (05 ▸ The comments
        // column): the draft is a durable file being edited in place, not unsaved work, and this
        // property's one consumer is File ▸ Save as Template's carve-out.
        let spy = CommentsSpy()
        let comments = makeComments(spy)

        comments.composer.edited("half a thought\n")
        #expect(comments.composer.isDirty)
        #expect(!comments.holdsUnsavedContent)
    }
}

// MARK: - Add Comment

@MainActor
@Suite("Card comments ▸ File ▸ Add Comment")
struct AddCommentCommandTests {

    @Test("The row turns Show Comments on and focuses the composer, whichever state it was in")
    func theRowDoesBoth() {
        // "File ▸ Add Comment flips the bit on when it's off (the gesture *is* the user choosing to
        // see comments — same persistence) and focuses the composer in one gesture" — and it focuses
        // *either way*, which is the clause that regresses silently.
        #expect(AddCommentCommand.effect(isShown: false) == (isShown: true, focusesComposer: true))
        #expect(AddCommentCommand.effect(isShown: true) == (isShown: true, focusesComposer: true))
    }

    @Test("Each request is its own — the counter never coalesces two")
    func requestsAreCounted() {
        let comments = CardComments()
        #expect(comments.focusComposerRequests == 0)
        comments.focusComposer()
        comments.focusComposer()
        #expect(comments.focusComposerRequests == 2)
    }

    @Test("All three comment rows are card-window-scoped and nothing else")
    func theRowsAreScopedToACardWindow() {
        #expect(!AddCommentCommand.isEnabled(nil))
        #expect(!ShowCommentsCommand.isEnabled(nil))
        #expect(!CommentsBesideBodyCommand.isEnabled(nil))

        let comments = CardComments()
        #expect(AddCommentCommand.isEnabled(comments))
        #expect(ShowCommentsCommand.isEnabled(comments))
        #expect(CommentsBesideBodyCommand.isEnabled(comments))
    }

    @Test("The lock does not disable them — showing a pane and focusing a buffer are not mutations")
    func theLockLeavesThemAlone() {
        let comments = CardComments()
        comments.isEditable = false
        #expect(AddCommentCommand.isEnabled(comments))
        #expect(ShowCommentsCommand.isEnabled(comments))
    }
}

// MARK: - The real wiring

@MainActor
@Suite("Card comments ▸ the store wiring")
struct CardCommentsWiringTests {

    /// The **real** seams, over a real store — `CardWindowHost.configureComments` is `static` and
    /// takes its collaborators precisely so this can drive the production wiring rather than a
    /// re-typed copy of it (`configureRawSource`'s precedent).
    @Test("A draft composed, posted and re-read round-trips through the wired seams")
    func theWiringRoundTrips() throws {
        let fixture = try WriterFixture()
        defer { fixture.tearDown() }
        let card = try makeCommentBoard(fixture)
        let store = try BoardStore(rootURL: fixture.root)
        let cardID = ItemID(rawValue: Ident.card1)

        let comments = CardComments()
        comments.isEditable = true
        comments.cardFolder = fixture.url(card)
        CardWindowHost.configureComments(comments, store: store, cardID: cardID)
        comments.open()

        comments.composer.edited("A remark.\n")
        #expect(comments.composer.flush() == .created)
        #expect(fixture.exists("\(card)/comments/.draft"))

        // Re-reading is restore-on-reopen, and it is only the read.
        comments.reload()
        #expect(comments.composer.text == "A remark.\n")

        #expect(comments.composer.postNow() != nil)
        comments.reload()
        #expect(comments.thread.comments.count == 1)
        #expect(comments.thread.comments[0].body == "A remark.\n")
        #expect(comments.composer.text == "", "the draft is gone — it is a comment now")
        #expect(!fixture.exists("\(card)/comments/.draft"))
    }

    @Test("Delete moves into comments/.trash/, and the close purge empties it")
    func deleteThenPurge() throws {
        let fixture = try WriterFixture()
        defer { fixture.tearDown() }
        let card = try makeCommentBoard(fixture)
        try fixture.item(commentPath(CommentIdent.one, inCard: card), commentText())
        let store = try BoardStore(rootURL: fixture.root)

        let comments = CardComments()
        comments.isEditable = true
        comments.cardFolder = fixture.url(card)
        CardWindowHost.configureComments(comments, store: store, cardID: ItemID(rawValue: Ident.card1))
        comments.open()
        #expect(comments.thread.comments.count == 1)

        comments.delete(ItemID(rawValue: CommentIdent.one))
        #expect(comments.thread.comments.isEmpty)
        #expect(fixture.exists("\(card)/comments/.trash/\(CommentIdent.one)"))

        comments.endSession()
        #expect(try fixture.entryNames("\(card)/comments/.trash").isEmpty)
    }

    @Test("An inline session's Cancel puts the file back through the wired save")
    func cancelWritesThroughTheStore() throws {
        let fixture = try WriterFixture()
        defer { fixture.tearDown() }
        let card = try makeCommentBoard(fixture)
        try fixture.item(commentPath(CommentIdent.one, inCard: card), commentText(body: "original\n"))
        let store = try BoardStore(rootURL: fixture.root)

        let comments = CardComments()
        comments.isEditable = true
        comments.cardFolder = fixture.url(card)
        CardWindowHost.configureComments(comments, store: store, cardID: ItemID(rawValue: Ident.card1))
        comments.open()

        comments.beginEdit(ItemID(rawValue: CommentIdent.one))
        comments.editing?.edited("rewritten\n")
        comments.editing?.flush()
        #expect(try fixture.indexText(commentPath(CommentIdent.one, inCard: card)).hasSuffix("rewritten\n"))

        comments.cancelEdit()
        #expect(try fixture.indexText(commentPath(CommentIdent.one, inCard: card)).hasSuffix("original\n"))
    }
}