// Copyright © 2022 Rangeproof Pty Ltd. All rights reserved.

import Foundation
import SessionUtilitiesKit

public class SnodeAuthenticatedRequestBody: Encodable {
    private enum CodingKeys: String, CodingKey {
        case pubkey
        case subaccount
        case timestampMs = "timestamp"
        case ed25519PublicKey = "pubkey_ed25519"
        case signatureBase64 = "signature"
        case subaccountSignatureBase64 = "subaccount_sig"
    }
    
    internal let authMethod: AuthenticationMethod
    internal let timestampMs: UInt64?
    
    var verificationBytes: [UInt8] { preconditionFailure("abstract class - override in subclass") }
    
    // MARK: - Initialization

    public init(
        authMethod: AuthenticationMethod,
        timestampMs: UInt64? = nil
    ) {
        self.authMethod = authMethod
        self.timestampMs = timestampMs
    }
    
    // MARK: - Codable
    
    public func encode(to encoder: Encoder) throws {
        var container: KeyedEncodingContainer<CodingKeys> = encoder.container(keyedBy: CodingKeys.self)
        
        // Generate the signature for the request for encoding
        let signature: Authentication.Signature = try authMethod.generateSignature(
            with: verificationBytes,
            using: try encoder.dependencies ?? { throw DependenciesError.missingDependencies }()
        )
        try container.encodeIfPresent(timestampMs, forKey: .timestampMs)
        
        switch authMethod.info {
            case .standard(let sessionId, let ed25519KeyPair):
                try container.encode(sessionId.hexString, forKey: .pubkey)
                try container.encode(ed25519KeyPair.publicKey.toHexString(), forKey: .ed25519PublicKey)
                
            case .groupAdmin(let sessionId, _):
                try container.encode(sessionId.hexString, forKey: .pubkey)
                
            case .groupMember(let sessionId, _):
                try container.encode(sessionId.hexString, forKey: .pubkey)
        }
        
        switch signature {
            case .standard(let signature):
                try container.encode(signature.toBase64(), forKey: .signatureBase64)
                
            case .subaccount(let subaccount, let subaccountSig, let signature):
                try container.encode(subaccount.toHexString(), forKey: .subaccount)
                try container.encode(signature.toBase64(), forKey: .signatureBase64)
                try container.encode(subaccountSig.toBase64(), forKey: .subaccountSignatureBase64)
        }
    }
}