import Foundation
import OpenClawChatUI
import OpenClawKit
import OpenClawProtocol
import OSLog

struct IOSGatewayChatTransport: OpenClawChatTransport {
    private static let logger = Logger(subsystem: "ai.openclaw", category: "ios.chat.transport")
    static let defaultChatSendTimeoutMs = 30000
    private let gateway: GatewayNodeSession

    private struct CreateSessionParams: Codable {
        var key: String
        var label: String?
        var parentSessionKey: String?
    }

    private struct RunParams: Codable {
        var sessionKey: String
        var runId: String
    }

    private struct ListSessionsParams: Codable {
        var includeGlobal: Bool
        var includeUnknown: Bool
        var limit: Int?
    }

    private struct SessionKeyParams: Codable {
        var key: String
    }

    private struct ChatSendParams: Codable {
        var sessionKey: String
        var message: String
        var thinking: String
        var attachments: [OpenClawChatAttachmentPayload]?
        var timeoutMs: Int
        var idempotencyKey: String
    }

    private struct AgentWaitParams: Codable {
        var runId: String
        var timeoutMs: Int
    }

    private struct AgentWaitResponse: Codable {
        var runId: String?
        var status: String?
        var error: String?
    }

    struct AgentWaitCompletion: Equatable {
        var runId: String
        var status: String
        var completed: Bool
    }

    static func isAgentWaitCompletionStatus(_ status: String) -> Bool {
        switch status.trimmingCharacters(in: .whitespacesAndNewlines).lowercased() {
        case "ok", "completed", "success", "succeeded":
            true
        default:
            false
        }
    }

    init(gateway: GatewayNodeSession) {
        self.gateway = gateway
    }

    static func agentWaitRequestTimeoutSeconds(timeoutMs: Int) -> Int {
        max(1, Int(ceil(Double(timeoutMs) / 1000.0)) + 5)
    }

    static func makeListSessionsParamsJSON(limit: Int?) throws -> String {
        try self.encodeParams(ListSessionsParams(includeGlobal: true, includeUnknown: false, limit: limit))
    }

    static func makeChatSendParamsJSON(
        sessionKey: String,
        message: String,
        thinking: String,
        idempotencyKey: String,
        attachments: [OpenClawChatAttachmentPayload]) throws -> String
    {
        let params = ChatSendParams(
            sessionKey: sessionKey,
            message: message,
            thinking: thinking,
            attachments: attachments.isEmpty ? nil : attachments,
            timeoutMs: self.defaultChatSendTimeoutMs,
            idempotencyKey: idempotencyKey)
        return try self.encodeParams(params)
    }

    static func decodeAgentWaitCompletion(_ data: Data, fallbackRunId: String) throws -> AgentWaitCompletion {
        let decoded = try JSONDecoder().decode(AgentWaitResponse.self, from: data)
        let status = (decoded.status ?? "unknown").lowercased()
        return AgentWaitCompletion(
            runId: decoded.runId ?? fallbackRunId,
            status: status,
            completed: self.isAgentWaitCompletionStatus(status))
    }

    private static func makeCreateSessionParamsJSON(
        key: String,
        label: String?,
        parentSessionKey: String?) throws -> String
    {
        let params = CreateSessionParams(
            key: key,
            label: label,
            parentSessionKey: parentSessionKey)
        return try self.encodeParams(params)
    }

    private static func makeRunParamsJSON(sessionKey: String, runId: String) throws -> String {
        try self.encodeParams(RunParams(sessionKey: sessionKey, runId: runId))
    }

    private static func makeSessionKeyParamsJSON(_ sessionKey: String) throws -> String {
        try self.encodeParams(SessionKeyParams(key: sessionKey))
    }

    private static func makeHistoryParamsJSON(sessionKey: String) throws -> String {
        struct Params: Codable { var sessionKey: String }
        return try self.encodeParams(Params(sessionKey: sessionKey))
    }

    private static func makeAgentWaitParamsJSON(runId: String, timeoutMs: Int) throws -> String {
        try self.encodeParams(AgentWaitParams(runId: runId, timeoutMs: timeoutMs))
    }

    private static func encodeParams(_ params: some Encodable) throws -> String {
        let data = try JSONEncoder().encode(params)
        guard let json = String(bytes: data, encoding: .utf8) else {
            throw EncodingError.invalidValue(
                params,
                EncodingError.Context(codingPath: [], debugDescription: "Encoded gateway params were not UTF-8"))
        }
        return json
    }

    func createSession(
        key: String,
        label: String?,
        parentSessionKey: String?) async throws -> OpenClawChatCreateSessionResponse
    {
        let json = try Self.makeCreateSessionParamsJSON(
            key: key,
            label: label,
            parentSessionKey: parentSessionKey)
        let res = try await self.gateway.request(method: "sessions.create", paramsJSON: json, timeoutSeconds: 15)
        return try JSONDecoder().decode(OpenClawChatCreateSessionResponse.self, from: res)
    }

    func abortRun(sessionKey: String, runId: String) async throws {
        let json = try Self.makeRunParamsJSON(sessionKey: sessionKey, runId: runId)
        _ = try await self.gateway.request(method: "chat.abort", paramsJSON: json, timeoutSeconds: 10)
    }

    func listSessions(limit: Int?) async throws -> OpenClawChatSessionsListResponse {
        let json = try Self.makeListSessionsParamsJSON(limit: limit)
        let res = try await self.gateway.request(method: "sessions.list", paramsJSON: json, timeoutSeconds: 15)
        return try JSONDecoder().decode(OpenClawChatSessionsListResponse.self, from: res)
    }

    func setActiveSessionKey(_ sessionKey: String) async throws {
        // Operator clients receive chat events without node-style subscriptions.
        // (chat.subscribe is a node event, not an operator RPC method.)
    }

    func resetSession(sessionKey: String) async throws {
        let json = try Self.makeSessionKeyParamsJSON(sessionKey)
        _ = try await self.gateway.request(method: "sessions.reset", paramsJSON: json, timeoutSeconds: 10)
    }

    func compactSession(sessionKey: String) async throws {
        let json = try Self.makeSessionKeyParamsJSON(sessionKey)
        _ = try await self.gateway.request(method: "sessions.compact", paramsJSON: json, timeoutSeconds: 10)
    }

    func requestHistory(sessionKey: String) async throws -> OpenClawChatHistoryPayload {
        let json = try Self.makeHistoryParamsJSON(sessionKey: sessionKey)
        let res = try await self.gateway.request(method: "chat.history", paramsJSON: json, timeoutSeconds: 15)
        return try JSONDecoder().decode(OpenClawChatHistoryPayload.self, from: res)
    }

    func sendMessage(
        sessionKey: String,
        message: String,
        thinking: String,
        idempotencyKey: String,
        attachments: [OpenClawChatAttachmentPayload]) async throws -> OpenClawChatSendResponse
    {
        let startLogMessage =
            "chat.send start sessionKey=\(sessionKey) "
                + "len=\(message.count) attachments=\(attachments.count)"
        Self.logger.info(
            "\(startLogMessage, privacy: .public)")
        GatewayDiagnostics.log(startLogMessage)
        let json = try Self.makeChatSendParamsJSON(
            sessionKey: sessionKey,
            message: message,
            thinking: thinking,
            idempotencyKey: idempotencyKey,
            attachments: attachments)
        do {
            let res = try await self.gateway.request(method: "chat.send", paramsJSON: json, timeoutSeconds: 35)
            let decoded = try JSONDecoder().decode(OpenClawChatSendResponse.self, from: res)
            Self.logger.info("chat.send ok runId=\(decoded.runId, privacy: .public)")
            GatewayDiagnostics.log("chat.send ok runId=\(decoded.runId) status=\(decoded.status)")
            return decoded
        } catch {
            Self.logger.error("chat.send failed \(error.localizedDescription, privacy: .public)")
            GatewayDiagnostics.log("chat.send failed error=\(error.localizedDescription)")
            throw error
        }
    }

    func waitForRunCompletion(runId rawRunId: String, timeoutMs: Int) async -> Bool {
        let runId = rawRunId.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !runId.isEmpty else { return false }

        do {
            let json = try Self.makeAgentWaitParamsJSON(runId: runId, timeoutMs: timeoutMs)
            let requestTimeoutSeconds = Self.agentWaitRequestTimeoutSeconds(timeoutMs: timeoutMs)
            GatewayDiagnostics.log("agent.wait start runId=\(runId)")
            let res = try await self.gateway.request(
                method: "agent.wait",
                paramsJSON: json,
                timeoutSeconds: requestTimeoutSeconds)
            let completion = try Self.decodeAgentWaitCompletion(res, fallbackRunId: runId)
            GatewayDiagnostics.log("agent.wait completed runId=\(completion.runId) status=\(completion.status)")
            if !completion.completed {
                Self.logger.warning(
                    "agent.wait status \(completion.status, privacy: .public) runId=\(runId, privacy: .public)")
            }
            return completion.completed
        } catch {
            Self.logger.warning("agent.wait failed \(error.localizedDescription, privacy: .public)")
            GatewayDiagnostics.log("agent.wait failed runId=\(runId) error=\(error.localizedDescription)")
            return false
        }
    }

    func requestHealth(timeoutMs: Int) async throws -> Bool {
        let seconds = max(1, Int(ceil(Double(timeoutMs) / 1000.0)))
        let res = try await self.gateway.request(method: "health", paramsJSON: nil, timeoutSeconds: seconds)
        return (try? JSONDecoder().decode(OpenClawGatewayHealthOK.self, from: res))?.ok ?? true
    }

    func events() -> AsyncStream<OpenClawChatTransportEvent> {
        AsyncStream { continuation in
            let task = Task {
                let stream = await self.gateway.subscribeServerEvents()
                for await evt in stream {
                    if Task.isCancelled { return }
                    switch evt.event {
                    case "tick":
                        continuation.yield(.tick)
                    case "seqGap":
                        continuation.yield(.seqGap)
                    case "health":
                        guard let payload = evt.payload else { break }
                        let ok = (try? GatewayPayloadDecoding.decode(
                            payload,
                            as: OpenClawGatewayHealthOK.self))?.ok ?? true
                        continuation.yield(.health(ok: ok))
                    case "chat":
                        guard let payload = evt.payload else { break }
                        if let chatPayload = try? GatewayPayloadDecoding.decode(
                            payload,
                            as: OpenClawChatEventPayload.self)
                        {
                            continuation.yield(.chat(chatPayload))
                        }
                    case "agent":
                        guard let payload = evt.payload else { break }
                        if let agentPayload = try? GatewayPayloadDecoding.decode(
                            payload,
                            as: OpenClawAgentEventPayload.self)
                        {
                            continuation.yield(.agent(agentPayload))
                        }
                    default:
                        break
                    }
                }
            }

            continuation.onTermination = { @Sendable _ in
                task.cancel()
            }
        }
    }
}