import Foundation
import Testing
@testable import Kanban

/// The welcome window's row derivation — 02-architecture.md § Launch and window lifecycle's
/// row-level failure rule, which is the one part of that screen a test can hold to account:
///
/// > A restored board that fails surfaces on welcome, row-level: its window doesn't open; welcome
/// > appears alongside whatever did restore, the failed board's recents row carrying fail-fast's
/// > specifics (load error) or the unavailable state per Graceful orphaning. Other restorations
/// > proceed unaffected — never a launch-time modal chain, **never a silent drop**.
///
/// "Never a silent drop" is the clause with teeth: a failure that matches no row has to come out
/// somewhere, and the only way to know it does is to ask the function that decides.

// MARK: - Fixtures

/// A record with nothing in it that matters except what a given test is about. Its bookmark is
/// **empty** because this function never resolves one — `RecentBoard` is constructed directly here,
/// so the availability classification is an input rather than a filesystem outcome.
private func record(
    name: String,
    at path: String,
    lanes: Int? = nil,
    cards: Int? = nil,
    opened: Date = Date(),
    icon: String? = nil,
    iconColor: String? = nil
) -> BoardRecord {
    BoardRecord(
        bookmark: Data(),
        displayName: name,
        lastKnownPath: path,
        lastOpened: opened,
        laneCount: lanes,
        cardCount: cards,
        icon: icon,
        iconColor: iconColor
    )
}

private func available(_ record: BoardRecord, at path: String? = nil) -> RecentBoard {
    .available(record, at: URL(fileURLWithPath: path ?? record.lastKnownPath, isDirectory: true))
}

// MARK: - Tests

@Suite("WelcomeRow")
struct WelcomeRowTests {

    // MARK: The three states

    @Test("An available record with stamped counts is an ordinary row")
    func availableRow() throws {
        let recent = available(record(name: "Roadmap", at: "/Boards/Roadmap.kanban", lanes: 3, cards: 12))

        let derived = WelcomeRow.derive(recents: [recent], failures: [])

        #expect(derived.rows.count == 1)
        let row = try #require(derived.rows.first)
        #expect(row.displayName == "Roadmap")
        #expect(row.isAvailable)
        #expect(row.canOpen)
        #expect(row.canReveal)
        #expect(row.caption == .counts(lanes: 3, cards: 12))
        #expect(row.countsSummary == "3 lanes · 12 cards")
        #expect(derived.unmatched.isEmpty)
    }

    @Test("A record that has never been closed shows an em dash, not zeroes")
    func unstampedCountsShowAPlaceholder() throws {
        let recent = available(record(name: "Fresh", at: "/Boards/Fresh"))

        let row = try #require(WelcomeRow.derive(recents: [recent], failures: []).rows.first)

        #expect(row.caption == .counts(lanes: nil, cards: nil))
        #expect(row.countsSummary == "—", "zero is a claim; an unstamped record makes none")
    }

    @Test("Counts are singular at one")
    func countsPluralize() {
        let recent = available(record(name: "Tiny", at: "/Boards/Tiny", lanes: 1, cards: 1))

        #expect(WelcomeRow.derive(recents: [recent], failures: []).rows.first?.countsSummary == "1 lane · 1 card")
    }

    @Test("An unresolvable bookmark is a dimmed row with Open and Reveal off — never a missing row")
    func unavailableRow() throws {
        let recent = RecentBoard.unavailable(record(name: "Archive", at: "/Volumes/Gone/Archive", lanes: 4, cards: 9))

        let row = try #require(WelcomeRow.derive(recents: [recent], failures: []).rows.first)

        #expect(!row.isAvailable)
        #expect(!row.canOpen)
        #expect(!row.canReveal)
        #expect(row.caption == .unavailable)
        #expect(row.displayName == "Archive", "an orphan still says which board it was")
    }

    // MARK: The failure join

    @Test("A failure naming a row renders on that row instead of in a list of its own")
    func failureLandsOnItsRow() throws {
        let recent = available(record(name: "Broken", at: "/Boards/Broken.kanban", lanes: 2, cards: 5))
        let failure = LaunchFailure(path: "/Boards/Broken.kanban", message: "index.md: schema 7 is from a newer version")

        let derived = WelcomeRow.derive(recents: [recent], failures: [failure])

        let row = try #require(derived.rows.first)
        #expect(row.caption == .failed("index.md: schema 7 is from a newer version"))
        #expect(derived.unmatched.isEmpty, "the row carried it — it must not also appear in the fallback list")
    }

    @Test("A failure outranks the counts and the unavailable state alike")
    func failureOutranksTheOtherCaptions() throws {
        let orphan = RecentBoard.unavailable(record(name: "Offline", at: "/Volumes/NAS/Offline", lanes: 2, cards: 2))
        let failure = LaunchFailure(path: "/Volumes/NAS/Offline", message: "This board is unavailable.")

        let row = try #require(WelcomeRow.derive(recents: [orphan], failures: [failure]).rows.first)

        #expect(row.caption == .failed("This board is unavailable."))
        #expect(!row.canOpen, "the caption changed; the row is still an orphan")
    }

    @Test("A bookmark that followed a move matches a failure recorded at the older path")
    func failureMatchesEitherOfARecordsPaths() {
        // The record was last *seen* at the old path; its bookmark now resolves to the new one.
        let moved = RecentBoard.available(
            record(name: "Moved", at: "/Boards/Old.kanban"),
            at: URL(fileURLWithPath: "/Boards/New.kanban", isDirectory: true)
        )

        let atOldPath = WelcomeRow.derive(
            recents: [moved],
            failures: [LaunchFailure(path: "/Boards/Old.kanban", message: "old")]
        )
        let atNewPath = WelcomeRow.derive(
            recents: [moved],
            failures: [LaunchFailure(path: "/Boards/New.kanban", message: "new")]
        )

        #expect(atOldPath.rows.first?.caption == .failed("old"))
        #expect(atNewPath.rows.first?.caption == .failed("new"))
        #expect(atOldPath.unmatched.isEmpty)
        #expect(atNewPath.unmatched.isEmpty)
    }

    @Test("Paths are compared standardized, so two spellings of one board are one board")
    func pathsAreStandardizedBeforeMatching() {
        let recent = available(record(name: "Roadmap", at: "/Boards/Roadmap.kanban"))
        let failure = LaunchFailure(path: "/Boards/./Sub/../Roadmap.kanban", message: "couldn't read it")

        let derived = WelcomeRow.derive(recents: [recent], failures: [failure])

        #expect(derived.rows.first?.caption == .failed("couldn't read it"))
        #expect(derived.unmatched.isEmpty)
    }

    @Test("The newest of several failures for one board is the caption, and all of them are consumed")
    func newestFailureWinsAndOlderOnesAreNotOrphaned() {
        let recent = available(record(name: "Retried", at: "/Boards/Retried"))
        let failures = [
            LaunchFailure(path: "/Boards/Retried", message: "first attempt"),
            LaunchFailure(path: "/Boards/Retried", message: "second attempt"),
        ]

        let derived = WelcomeRow.derive(recents: [recent], failures: failures)

        #expect(derived.rows.first?.caption == .failed("second attempt"), "the newest describes the file as it is now")
        #expect(derived.unmatched.isEmpty, "the older attempt must not resurface as if nothing had shown it")
    }

    @Test("A failure naming no record keeps a fallback of its own — never a silent drop")
    func failureWithNoRowFallsBack() {
        let recent = available(record(name: "Roadmap", at: "/Boards/Roadmap.kanban"))
        let stray = LaunchFailure(path: "/Downloads/not-a-board", message: "index.md: no such file or directory")

        let derived = WelcomeRow.derive(recents: [recent], failures: [stray])

        #expect(derived.rows.count == 1)
        #expect(derived.rows.first?.caption == .counts(lanes: nil, cards: nil), "the unrelated row is untouched")
        #expect(derived.unmatched.map(\.message) == ["index.md: no such file or directory"])
    }

    @Test("Other rows are unaffected by a failure on one of them")
    func failuresDoNotBleedBetweenRows() {
        let recents = [
            available(record(name: "Good", at: "/Boards/Good", lanes: 1, cards: 1)),
            available(record(name: "Bad", at: "/Boards/Bad")),
        ]
        let failure = LaunchFailure(path: "/Boards/Bad", message: "boom")

        let derived = WelcomeRow.derive(recents: recents, failures: [failure])

        #expect(derived.rows[0].caption == .counts(lanes: 1, cards: 1))
        #expect(derived.rows[1].caption == .failed("boom"))
    }

    // MARK: Order and naming

    @Test("The derivation preserves the registry's order and never re-sorts")
    func orderIsTheRegistrys() {
        let recents = [
            available(record(name: "Third", at: "/Boards/C", opened: Date(timeIntervalSince1970: 3))),
            available(record(name: "First", at: "/Boards/A", opened: Date(timeIntervalSince1970: 1))),
            available(record(name: "Second", at: "/Boards/B", opened: Date(timeIntervalSince1970: 2))),
        ]

        let derived = WelcomeRow.derive(recents: recents, failures: [])

        #expect(derived.rows.map(\.displayName) == ["Third", "First", "Second"],
                "the sort rule lives in BoardRegistry.recents() and must not be duplicated here")
    }

    @Test("A record's cached icon and iconColor ride straight through to its row")
    func iconAndIconColorPassThrough() throws {
        let recent = available(record(name: "Roadmap", at: "/Boards/Roadmap.kanban", icon: "star.fill", iconColor: "fern"))

        let row = try #require(WelcomeRow.derive(recents: [recent], failures: []).rows.first)

        #expect(row.icon == "star.fill")
        #expect(row.iconColor == "fern")
    }

    @Test("A record with no cached icon carries nil through to its row — the renderer's default to draw")
    func noIconIsNilNotAGuess() throws {
        let recent = available(record(name: "Roadmap", at: "/Boards/Roadmap.kanban"))

        let row = try #require(WelcomeRow.derive(recents: [recent], failures: []).rows.first)

        #expect(row.icon == nil)
        #expect(row.iconColor == nil)
    }

    @Test("A record with no display name falls back to its folder name, extension stripped")
    func displayNameFallsBackToTheFolderName() {
        let recent = available(record(name: "", at: "/Boards/Untitled.kanban"))

        #expect(WelcomeRow.derive(recents: [recent], failures: []).rows.first?.displayName == "Untitled")
    }

    @Test("The location line is the containing folder, not the board's own path")
    func locationIsTheContainingFolder() {
        let recent = available(record(name: "Roadmap", at: "/Boards/Work/Roadmap.kanban"))

        #expect(WelcomeRow.derive(recents: [recent], failures: []).rows.first?.location == "/Boards/Work")
    }

    @Test("An unavailable row's location comes from where it was last seen")
    func unavailableLocationUsesLastKnownPath() {
        let recent = RecentBoard.unavailable(record(name: "Archive", at: "/Volumes/Gone/Boards/Archive"))

        #expect(WelcomeRow.derive(recents: [recent], failures: []).rows.first?.location == "/Volumes/Gone/Boards")
    }

    @Test("An empty registry derives no rows and drops no failures")
    func emptyRecentsStillSurfaceFailures() {
        let stray = LaunchFailure(path: "/Downloads/whatever", message: "not a board")

        let derived = WelcomeRow.derive(recents: [], failures: [stray])

        #expect(derived.rows.isEmpty)
        #expect(derived.unmatched.count == 1)
    }
}