//
//  PersistenceService.swift
//  Zyquo MLX
//
//  Author: Simon-Pierre Boucher
//  Mail: contact@spboucher.ai
//

import Foundation

/// Canonical data locations (charter naming conventions) and small JSON
/// persistence helpers used across stores.
enum PersistenceService {

    /// `~/Library/Application Support/ZyquoMLX/`
    static var appSupportDirectory: URL {
        FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
            .appendingPathComponent("ZyquoMLX", isDirectory: true)
    }

    static var modelsDirectory: URL {
        appSupportDirectory.appendingPathComponent("Models", isDirectory: true)
    }

    static var datasetsDirectory: URL {
        appSupportDirectory.appendingPathComponent("Datasets", isDirectory: true)
    }

    static var runsDirectory: URL {
        appSupportDirectory.appendingPathComponent("Runs", isDirectory: true)
    }

    static var pythonDirectory: URL {
        appSupportDirectory.appendingPathComponent("py", isDirectory: true)
    }

    /// Create all canonical directories if missing (first launch).
    static func ensureDirectories() throws {
        let fm = FileManager.default
        for url in [appSupportDirectory, modelsDirectory, datasetsDirectory, runsDirectory] {
            try fm.createDirectory(at: url, withIntermediateDirectories: true)
        }
    }

    static func loadJSON<T: Decodable>(_ type: T.Type, from url: URL) throws -> T {
        let data = try Data(contentsOf: url)
        let decoder = JSONDecoder()
        decoder.dateDecodingStrategy = .iso8601
        return try decoder.decode(type, from: data)
    }

    static func saveJSON<T: Encodable>(_ value: T, to url: URL) throws {
        let encoder = JSONEncoder()
        encoder.dateEncodingStrategy = .iso8601
        encoder.outputFormatting = [.prettyPrinted, .sortedKeys]
        try encoder.encode(value).write(to: url, options: .atomic)
    }
}