import Foundation

/// A real-world encounter between two present users.
///
/// An encounter is deliberately **anonymous** until both parties mutually
/// consent to reveal. Until then it is a "silhouette" — a proof that two
/// humans were physically near each other, with no identity attached.
struct Encounter: Identifiable, Codable, Hashable {
    let id: UUID
    let remoteAnonToken: String
    let timestamp: Date
    let tier: DistanceTier
    let engine: ProximityEngine

    /// Coarse geohash (optional). Never precise location.
    var geohash: String?

    /// The relationship state of this encounter.
    var status: EncounterStatus

    /// A human-readable hint, e.g. "Cafe on 5th Ave" if the user tagged it.
    var placeHint: String?

    init(
        id: UUID = UUID(),
        remoteAnonToken: String,
        timestamp: Date = Date(),
        tier: DistanceTier,
        engine: ProximityEngine,
        geohash: String? = nil,
        status: EncounterStatus = .silhouette,
        placeHint: String? = nil
    ) {
        self.id = id
        self.remoteAnonToken = remoteAnonToken
        self.timestamp = timestamp
        self.tier = tier
        self.engine = engine
        self.geohash = geohash
        self.status = status
        self.placeHint = placeHint
    }
}

/// Relationship lifecycle of an encounter.
enum EncounterStatus: String, Codable, Hashable {
    /// Seen but not yet acknowledged. A silhouette.
    case silhouette
    /// This user has sent a "wave" (interest) but the other hasn't replied.
    case waved
    /// Both parties waved — identities revealed, chat unlocked.
    case mutual
    /// One party declined or blocked. Permanently removed from the graph.
    case declined
}