import Foundation
import SwiftData

/// The bundled immutable starter-split library, brought back on demand. The seeds
/// themselves — fixed ULIDs, byte-canonical bundle JSON — live in `SeedLibrary`;
/// editing one clones it and permanently tombstones the seed (see
/// `SyncEngine.save(split:)`). The true first-run case is handled automatically by
/// `SyncEngine.autoSeedIfEmpty`; this on-demand path (the "Add Starter Splits"
/// button) is for a user who wants the starters back after removing some.
enum SplitSeeder {
    /// Add every starter split the user doesn't already have. For each seed:
    ///   • skip if a live split with the same NAME exists — a user's edited clone of
    ///     "Upper Body" must not be joined by a resurrected seed of the same name;
    ///   • else if the seed was deleted (tombstoned), restore it (lifting the veto);
    ///   • else write it fresh.
    /// Seed `order` values are fixed (0–3); a collision with a user split's order is
    /// an accepted cosmetic tie. Idempotent against double-taps and partial prior seeds.
    @MainActor
    static func seedDefaults(into context: ModelContext, using sync: SyncEngine) async {
        let existing = (try? context.fetch(FetchDescriptor<Split>())) ?? []
        let existingNames = Set(existing.map(\.name))

        for seed in SeedLibrary.seeds {
            if existingNames.contains(seed.doc.name) { continue }
            if await sync.isTombstoned(id: seed.id) {
                await sync.restoreSeed(seed)
            } else {
                await sync.writeSeed(seed)
            }
        }
    }
}