import Foundation
import Combine
import JSONRPC
import LanguageClient
import LanguageServerProtocol
import Logger

protocol ServerRequestHandler {
    func handleRequest(_ request: AnyJSONRPCRequest, workspaceURL: URL, callback: @escaping (AnyJSONRPCResponse) -> Void, service: GitHubCopilotService?)
}

class ServerRequestHandlerImpl : ServerRequestHandler {
    public static let shared = ServerRequestHandlerImpl()
    private let conversationContextHandler: ConversationContextHandler = ConversationContextHandlerImpl.shared
    private let watchedFilesHandler: WatchedFilesHandler = WatchedFilesHandlerImpl.shared
    
    func handleRequest(_ request: AnyJSONRPCRequest, workspaceURL: URL, callback: @escaping (AnyJSONRPCResponse) -> Void, service: GitHubCopilotService?) {
        let methodName = request.method
        do {
            switch methodName {
            case "conversation/context":
                let params = try JSONEncoder().encode(request.params)
                let contextParams = try JSONDecoder().decode(ConversationContextParams.self, from: params)
                conversationContextHandler.handleConversationContext(
                    ConversationContextRequest(id: request.id, method: request.method, params: contextParams),
                    completion: callback)
                
            case "copilot/watchedFiles":
                let params = try JSONEncoder().encode(request.params)
                let watchedFilesParams = try JSONDecoder().decode(WatchedFilesParams.self, from: params)
                watchedFilesHandler.handleWatchedFiles(WatchedFilesRequest(id: request.id, method: request.method, params: watchedFilesParams), workspaceURL: workspaceURL, completion: callback, service: service)
                
            default:
                break
            }
        } catch {
            handleError(request, error: error, callback: callback)
        }
    }
    
    private func handleError(_ request: AnyJSONRPCRequest, error: Error, callback: @escaping (AnyJSONRPCResponse) -> Void) {
        callback(
            AnyJSONRPCResponse(
                id: request.id,
                result: JSONValue.array([
                    JSONValue.null,
                    JSONValue.hash([
                        "code": .number(-32602/* Invalid params */),
                        "message": .string("Error: \(error.localizedDescription)")])
                ])
            )
        )
        Logger.gitHubCopilot.error(error)
    }
}