//
//  PersistenceService.swift
//  Zyquo Router
//
//  Author: Simon-Pierre Boucher
//  Mail: contact@spboucher.ai
//
//  JSON persistence in ~/Library/Application Support/ZyquoRouter/:
//    aliases.json, chains.json, local-keys.json, usage.json, settings.json
//  Ported from Zyquo Cloud; conversation-specific storage dropped (the Router
//  keeps generic named-document load/save only).
//

import Foundation

struct PersistenceService {
    static let shared = PersistenceService()

    let rootDirectory: URL

    private let encoder: JSONEncoder
    private let decoder: JSONDecoder

    init(rootDirectory: URL? = nil) {
        let base = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
        self.rootDirectory = rootDirectory ?? base.appendingPathComponent("ZyquoRouter")
        encoder = JSONEncoder()
        encoder.outputFormatting = [.prettyPrinted, .sortedKeys]
        encoder.dateEncodingStrategy = .iso8601
        decoder = JSONDecoder()
        decoder.dateDecodingStrategy = .iso8601
        try? FileManager.default.createDirectory(at: self.rootDirectory, withIntermediateDirectories: true)
    }

    // MARK: - Generic documents (aliases, chains, keys, settings…)

    func load<T: Decodable>(_ type: T.Type, from fileName: String) -> T? {
        let url = rootDirectory.appendingPathComponent(fileName)
        guard let data = try? Data(contentsOf: url) else { return nil }
        return try? decoder.decode(type, from: data)
    }

    func save<T: Encodable>(_ value: T, to fileName: String) {
        let url = rootDirectory.appendingPathComponent(fileName)
        guard let data = try? encoder.encode(value) else { return }
        try? data.write(to: url, options: .atomic)
    }
}