import Foundation
import BinaryCodable

struct TokenStorage {
    
    private(set) var tokens: Set<String>
    
    private let fileUrl: URL
    
    private let encoder = BinaryEncoder()
    
    init(in folder: URL) {
        tokens = []
        fileUrl = folder.appendingPathComponent("tokens")
        
        loadTokensFromDisk()
    }
    
    private mutating func loadTokensFromDisk() {
        guard FileManager.default.fileExists(atPath: fileUrl.path) else {
            return
        }
        do {
            let data = try Data(contentsOf: fileUrl)
            tokens = try BinaryDecoder().decode(from: data)
        } catch {
            log(error: "Failed to read token file: \(error)")
        }
    }
    
    mutating func add(_ tokenUpload: TokenUpload) {
        if let oldToken = tokenUpload.previousToken {
            tokens.remove(oldToken.hex)
        }
        tokens.insert(tokenUpload.currentToken.hex)
        do {
            let data = try encoder.encode(tokens)
            try data.write(to: fileUrl)
        } catch {
            log(error: "Failed to write token file: \(error)")
        }
    }
    
}