import Foundation

struct DraftRecord: Codable, Identifiable {
    var id: String { item.slug.isEmpty ? item.title : item.slug }
    var serverURL: String
    var savedAt: Date
    var item: ContentItem
    var markdown: String
}

final class DraftStore {
    private let folder: URL

    init() {
        let base = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask).first
            ?? URL(fileURLWithPath: NSTemporaryDirectory())
        folder = base.appendingPathComponent("TCMS Mac Client", isDirectory: true)
        try? FileManager.default.createDirectory(at: folder, withIntermediateDirectories: true)
    }

    func save(item: ContentItem, markdown: String, serverURL: String) throws {
        let record = DraftRecord(serverURL: serverURL, savedAt: Date(), item: item, markdown: markdown)
        let data = try JSONEncoder.tcms.encode(record)
        try data.write(to: fileURL(for: record.id), options: .atomic)
    }

    func remove(id: String) {
        try? FileManager.default.removeItem(at: fileURL(for: id))
    }

    func loadAll(serverURL: String) -> [DraftRecord] {
        let urls = (try? FileManager.default.contentsOfDirectory(at: folder, includingPropertiesForKeys: nil)) ?? []
        return urls.compactMap { url in
            guard let data = try? Data(contentsOf: url),
                  let record = try? JSONDecoder.tcms.decode(DraftRecord.self, from: data),
                  record.serverURL == serverURL else {
                return nil
            }
            return record
        }
        .sorted { $0.savedAt > $1.savedAt }
    }

    private func fileURL(for id: String) -> URL {
        let safe = id.replacingOccurrences(of: "[^A-Za-z0-9._-]+", with: "-", options: .regularExpression)
        return folder.appendingPathComponent(safe.isEmpty ? "untitled" : safe).appendingPathExtension("json")
    }
}

private extension JSONEncoder {
    static var tcms: JSONEncoder {
        let encoder = JSONEncoder()
        encoder.outputFormatting = [.prettyPrinted, .sortedKeys]
        encoder.dateEncodingStrategy = .iso8601
        return encoder
    }
}

private extension JSONDecoder {
    static var tcms: JSONDecoder {
        let decoder = JSONDecoder()
        decoder.dateDecodingStrategy = .iso8601
        return decoder
    }
}