import Foundation
import FoundationNetworking
import Crypto

public func createPrivateP256Key() -> P256.Signing.PrivateKey {
    return P256.Signing.PrivateKey()
}

public func createPublickP256Key(privateKey: P256.Signing.PrivateKey ) -> P256.Signing.PublicKey {
    return privateKey.publicKey
}

public func publicP256_2_Spki(publicKey: P256.Signing.PublicKey) -> String {
    return publicKey.pemRepresentation
}

public func privateP256_2_pem(privateKey: P256.Signing.PrivateKey) -> String {
    return privateKey.pemRepresentation
}

// UGLY: Refactor to make it easier to comprehend
public func fetchPrivateP256Key(deviceID: UInt128) async throws -> P256.Signing.PrivateKey {

    // UGLY: but fast
    let privateKeyFolder = ProcessInfo.processInfo.environment["PRIVATE_KEY_FOLDER"] ?? "./Private/PrivateKeysP256"

    let keyFilePath = "\(privateKeyFolder)/\(deviceID)-Kr.pem"

    do {
        let key = try pem2_P265_PrivateKey(filePath: keyFilePath)
        // TODO: send public key to another server
        let publicKey = key.publicKey.pemRepresentation

        // UGLY: hardcoded
        var httpRequest = URLRequest(url: URL(string: "http://publick-key-db.internal/key")!)
        httpRequest.setValue("application/json", forHTTPHeaderField: "Content-Type")
        httpRequest.httpMethod = "POST"

        let message: [String : Encodable] = [         
            "deviceID": deviceID,
            "publicKey": publicKey
        ]
        let data = try JSONSerialization.data(withJSONObject: message)
        httpRequest.httpBody = data

        let _ = try await URLSession.shared.upload(for: httpRequest, from: data)

        return key
    } catch {
        // Do nothing
    }

    do {
        let key = createPrivateP256Key()
        try privateP256_2_pem(privateKey: key).write(to: URL(filePath: keyFilePath), atomically: true, encoding: String.Encoding.utf8)
        return key
    } catch {
        throw ParsingError.ImpossibleToWriteKeyToFileSystem
    }

    
    
}

private func pem2_P265_PrivateKey(filePath: String) throws -> P256.Signing.PrivateKey {

    let pemEncodedKey = try String(contentsOf: URL(filePath: filePath), encoding: .utf8)
    return try P256.Signing.PrivateKey(pemRepresentation: pemEncodedKey)

}