import Foundation

/// What `mr list` is narrowed to. The command takes no `--assignee`, so
/// this offers none.
nonisolated struct MRFilter: Equatable, Sendable {

    enum State: String, CaseIterable, Identifiable, Sendable {
        case open, merged, closed
        case sourceGone = "source_gone"
        case all

        var id: String { rawValue }
        var label: String { stateLabel(rawValue) }
    }

    var state: State = .open
    var search = ""
    var label: String?
    var author: String?
    var milestone: String?

    func flags() -> [String] {
        var flags = ["--state", state.rawValue]
        flags += filterFlag("--search", search)
        flags += filterFlag("--label", label)
        flags += filterFlag("--author", author)
        flags += filterFlag("--milestone", milestone)
        return flags
    }

    var isNarrowed: Bool { flags().count > 2 }

    var emptyMessage: String {
        let noun = "merge requests"
        if isNarrowed {
            return state == .all
                ? "No \(noun) match these filters."
                : "No \(state.label.lowercased()) \(noun) match these filters."
        }
        return state == .all ? "No \(noun)." : "No \(state.label.lowercased()) \(noun)."
    }
}

/// A wire state (`open`, `source_gone`) as the app shows it: sentence
/// case, underscores as spaces.
nonisolated func stateLabel(_ state: String) -> String {
    let words = state.replacingOccurrences(of: "_", with: " ")
    return words.prefix(1).uppercased() + words.dropFirst()
}