import Foundation

/// Keeps locally signed copies discoverable after reopening a lead or restarting the app.
/// The source version is part of the key so a newer contract never inherits an older signature.
struct LeadSignedDocumentStore {
    var directory: URL = URL.applicationSupportDirectory
        .appending(path: "SignedLeadDocuments", directoryHint: .isDirectory)

    private struct Record: Codable {
        let leadID: String
        let salesCode: String
        let documentID: String
        let fileID: String
        let version: String
        let filename: String
    }

    func save(url: URL, document: LeadDocument, leadID: String, salesCode: String) throws {
        let record = Record(leadID: leadID, salesCode: salesCode, documentID: document.id,
                            fileID: document.file.id, version: document.file.version,
                            filename: url.lastPathComponent)
        let data = try JSONEncoder().encode(record)
        try FileManager.default.createDirectory(at: directory, withIntermediateDirectories: true)
        try data.write(to: directory.appending(path: url.deletingPathExtension().lastPathComponent + ".json"),
                       options: .atomic)
    }

    func savedURLs(documents: [LeadDocument], leadID: String, salesCode: String) -> [String: URL] {
        guard let files = try? FileManager.default.contentsOfDirectory(
            at: directory, includingPropertiesForKeys: nil
        ) else { return [:] }
        var result: [String: URL] = [:]
        for file in files where file.pathExtension == "json" {
            guard let data = try? Data(contentsOf: file),
                  let record = try? JSONDecoder().decode(Record.self, from: data),
                  record.leadID == leadID, record.salesCode == salesCode,
                  documents.contains(where: {
                      $0.id == record.documentID && $0.file.id == record.fileID && $0.file.version == record.version
                  }) else { continue }
            let url = directory.appending(path: record.filename)
            if FileManager.default.fileExists(atPath: url.path) {
                result[record.documentID] = url
            }
        }
        return result
    }
}