import Foundation
import Observation

/// `snippet list` — the caller's own snippets at every visibility, or an
/// owner's public ones — paginated, plus `snippet create`.
@Observable
@MainActor
final class SnippetListViewModel {

    let list: PagedListModel<Snippet>
    /// nil lists the caller's own.
    let owner: String?
    private(set) var actionError: String?
    private(set) var working = false

    private let client: GitbayClient

    init(client: GitbayClient, owner: String?) {
        self.client = client
        self.owner = owner
        list = PagedListModel(
            client: client,
            argv: ["snippet", "list"] + (owner.map { [$0] } ?? []),
            emptyMessage: owner == nil
                ? "No snippets yet. Create one from the + button."
                : "\(owner ?? "") has no public snippets."
        )
    }

    var state: LoadState<[Snippet]> { list.state }

    func load() async {
        await list.reload()
    }

    /// `snippet create <filename> [--description <d>] [--visibility <v>]
    /// < file` — the file is bare stdin. An empty description sends no
    /// flag. Returns the created snippet, or nil with `actionError` set.
    func create(filename: String, description: String, visibility: String, content: String) async -> Snippet? {
        var argv = ["snippet", "create", filename.trimmingCharacters(in: .whitespaces)]
        let description = description.trimmingCharacters(in: .whitespacesAndNewlines)
        if !description.isEmpty { argv += ["--description", description] }
        argv += ["--visibility", visibility]
        working = true
        actionError = nil
        defer { working = false }
        do {
            let created = try await client.run(argv, stdin: content, as: Snippet.self)
            await list.reload()
            return created
        } catch let error as GitbayError {
            // Exit 2 here is the server validating the file name, the
            // size or the per-account cap — written for the person.
            if case .usage(let message) = error, !message.isEmpty {
                actionError = message
            } else {
                actionError = error.userFacingMessage
            }
            return nil
        } catch {
            actionError = GitbayError.transport(error).userFacingMessage
            return nil
        }
    }
}