import Foundation
import Observation

/// One directory of `repo tree`. Navigation pushes a new instance per
/// level, so back is free and each level revalidates independently.
@Observable
@MainActor
final class TreeViewModel {

    private(set) var state: LoadState<TreeListing> = .loading

    private let client: GitbayClient
    let repoPath: String
    let directory: String
    let ref: String?

    init(client: GitbayClient, repoPath: String, directory: String = "", ref: String? = nil) {
        self.client = client
        self.repoPath = repoPath
        self.directory = directory
        self.ref = ref
    }

    /// Directories first, then files, both alphabetically — the ordering
    /// every forge uses.
    var entries: [TreeEntry] {
        guard let listing = state.value else { return [] }
        return listing.entries.sorted {
            if $0.isDirectory != $1.isDirectory { return $0.isDirectory }
            return $0.name.localizedStandardCompare($1.name) == .orderedAscending
        }
    }

    func load() async {
        var argv = ["repo", "tree", repoPath]
        if !directory.isEmpty { argv.append(directory) }
        if let ref { argv.append(contentsOf: ["--ref", ref]) }
        do {
            state = .loaded(try await client.read(argv, as: TreeListing.self))
        } catch {
            state = .from(error)
        }
    }

    func childDirectory(_ entry: TreeEntry) -> String {
        directory.isEmpty ? entry.name : "\(directory)/\(entry.name)"
    }
}