import CopilotModel
import Foundation
import LanguageClient
import LanguageServerProtocol
import XPCShared

public protocol CopilotAuthServiceType {
    func checkStatus() async throws -> CopilotStatus
    func signInInitiate() async throws -> (verificationUri: String, userCode: String)
    func signInConfirm(userCode: String) async throws -> (username: String, status: CopilotStatus)
    func signOut() async throws -> CopilotStatus
    func version() async throws -> String
}

public protocol CopilotSuggestionServiceType {
    func getCompletions(
        fileURL: URL,
        content: String,
        cursorPosition: CursorPosition,
        tabSize: Int,
        indentSize: Int,
        usesTabsForIndentation: Bool,
        ignoreSpaceOnlySuggestions: Bool
    ) async throws -> [CopilotCompletion]
    func notifyAccepted(_ completion: CopilotCompletion) async
    func notifyRejected(_ completions: [CopilotCompletion]) async
}

protocol CopilotLSP {
    func sendRequest<E: CopilotRequestType>(_ endpoint: E) async throws -> E.Response
}

public class CopilotBaseService {
    let projectRootURL: URL
    var server: CopilotLSP

    init(designatedServer: CopilotLSP) {
        projectRootURL = URL(fileURLWithPath: "/")
        server = designatedServer
    }

    init(projectRootURL: URL) {
        self.projectRootURL = projectRootURL
        server = {
            let supportURL = FileManager.default.urls(
                for: .applicationSupportDirectory,
                in: .userDomainMask
            ).first!.appendingPathComponent("com.intii.CopilotForXcode")
            if !FileManager.default.fileExists(atPath: supportURL.path) {
                try? FileManager.default
                    .createDirectory(at: supportURL, withIntermediateDirectories: false)
            }
            let executionParams = {
                let nodePath = UserDefaults.shared.string(forKey: SettingsKey.nodePath) ?? ""
                return Process.ExecutionParameters(
                    path: "/usr/bin/env",
                    arguments: [
                        nodePath.isEmpty ? "node" : nodePath,
                        Bundle.main.url(
                            forResource: "agent",
                            withExtension: "js",
                            subdirectory: "copilot/dist"
                        )!.path,
                        "--stdio",
                    ],
                    environment: [
                        "PATH": "/usr/bin:/usr/local/bin",
                    ],
                    currentDirectoryURL: supportURL
                )
            }()
            let localServer = LocalProcessServer(executionParameters: executionParams)
            localServer.logMessages = false
            let server = InitializingServer(server: localServer)
            server.notificationHandler = { _, respond in
                respond(nil)
            }

            server.initializeParamsProvider = {
                let capabilities = ClientCapabilities(
                    workspace: nil,
                    textDocument: nil,
                    window: nil,
                    general: nil,
                    experimental: nil
                )

                return InitializeParams(
                    processId: Int(ProcessInfo.processInfo.processIdentifier),
                    clientInfo: .init(name: "Copilot for Xcode"),
                    locale: nil,
                    rootPath: projectRootURL.path,
                    rootUri: projectRootURL.path,
                    initializationOptions: nil,
                    capabilities: capabilities,
                    trace: nil,
                    workspaceFolders: nil
                )
            }

            server.notificationHandler = { _, respond in
                respond(nil)
            }

            return server
        }()
    }
}

public final class CopilotAuthService: CopilotBaseService, CopilotAuthServiceType {
    public init() {
        let home = FileManager.default.homeDirectoryForCurrentUser
        super.init(projectRootURL: home)
        Task {
            try? await server.sendRequest(CopilotRequest.SetEditorInfo())
        }
    }

    public func checkStatus() async throws -> CopilotStatus {
        try await server.sendRequest(CopilotRequest.CheckStatus()).status
    }

    public func signInInitiate() async throws -> (verificationUri: String, userCode: String) {
        let result = try await server.sendRequest(CopilotRequest.SignInInitiate())
        return (result.verificationUri, result.userCode)
    }

    public func signInConfirm(userCode: String) async throws
        -> (username: String, status: CopilotStatus)
    {
        let result = try await server.sendRequest(CopilotRequest.SignInConfirm(userCode: userCode))
        return (result.user, result.status)
    }

    public func signOut() async throws -> CopilotStatus {
        try await server.sendRequest(CopilotRequest.SignOut()).status
    }

    public func version() async throws -> String {
        try await server.sendRequest(CopilotRequest.GetVersion()).version
    }
}

public final class CopilotSuggestionService: CopilotBaseService, CopilotSuggestionServiceType {
    override public init(projectRootURL: URL = URL(fileURLWithPath: "/")) {
        super.init(projectRootURL: projectRootURL)
    }
    
    override init(designatedServer: CopilotLSP) {
        super.init(designatedServer: designatedServer)
    }

    public func getCompletions(
        fileURL: URL,
        content: String,
        cursorPosition: CursorPosition,
        tabSize: Int,
        indentSize: Int,
        usesTabsForIndentation: Bool,
        ignoreSpaceOnlySuggestions: Bool
    ) async throws -> [CopilotCompletion] {
        guard let languageId = languageIdentifierFromFileURL(fileURL) else { return [] }

        let relativePath = {
            let filePath = fileURL.path
            let rootPath = projectRootURL.path
            if let range = filePath.range(of: rootPath),
               range.lowerBound == filePath.startIndex
            {
                let relativePath = filePath.replacingCharacters(
                    in: filePath.startIndex..<range.upperBound,
                    with: ""
                )
                return relativePath
            }
            return filePath
        }()

        let completions = try await server
            .sendRequest(CopilotRequest.GetCompletionsCycling(doc: .init(
                source: content,
                tabSize: tabSize,
                indentSize: indentSize,
                insertSpaces: !usesTabsForIndentation,
                path: fileURL.path,
                uri: fileURL.path,
                relativePath: relativePath,
                languageId: languageId,
                position: cursorPosition
            )))
            .completions
            .filter { completion in
                if ignoreSpaceOnlySuggestions {
                    return !completion.text.allSatisfy { $0.isWhitespace || $0.isNewline }
                }
                return true
            }

        return completions
    }

    public func notifyAccepted(_ completion: CopilotCompletion) async {
        _ = try? await server.sendRequest(
            CopilotRequest.NotifyAccepted(completionUUID: completion.uuid)
        )
    }

    public func notifyRejected(_ completions: [CopilotCompletion]) async {
        _ = try? await server.sendRequest(
            CopilotRequest.NotifyRejected(completionUUIDs: completions.map(\.uuid))
        )
    }
}

extension InitializingServer: CopilotLSP {
    func sendRequest<E: CopilotRequestType>(_ endpoint: E) async throws -> E.Response {
        try await sendRequest(endpoint.request)
    }
}