import Foundation
import LibXray

/// Thin wrapper around LibXray.Invoke (macOS Manager engine.Start for Xray).
enum LibXrayCore {
    struct InvokeError: LocalizedError {
        var message: String
        var errorDescription: String? { message }
    }

    static func runJSON(_ configJSON: String) throws {
        let payload: [String: Any] = [
            "apiVersion": 1,
            "method": "runXrayFromJson",
            "payload": ["configJSON": configJSON],
        ]
        try invoke(payload)
    }

    static func runFile(_ configPath: String) throws {
        let payload: [String: Any] = [
            "apiVersion": 1,
            "method": "runXray",
            "payload": ["configPath": configPath],
        ]
        try invoke(payload)
    }

    static func stop() {
        let payload: [String: Any] = [
            "apiVersion": 1,
            "method": "stopXray",
            "payload": [:] as [String: Any],
        ]
        _ = try? invoke(payload)
    }

    static func isRunning() -> Bool {
        let payload: [String: Any] = [
            "apiVersion": 1,
            "method": "getXrayState",
            "payload": [:] as [String: Any],
        ]
        guard let data = try? invokeData(payload),
              let running = data["running"] as? Bool
        else { return false }
        return running
    }

    static func version() -> String {
        let payload: [String: Any] = [
            "apiVersion": 1,
            "method": "xrayVersion",
            "payload": [:] as [String: Any],
        ]
        guard let data = try? invokeData(payload),
              let v = data["version"] as? String
        else { return "?" }
        return v
    }

    @discardableResult
    private static func invoke(_ payload: [String: Any]) throws -> [String: Any]? {
        let data = try invokeData(payload)
        return data
    }

    private static func invokeData(_ payload: [String: Any]) throws -> [String: Any]? {
        let reqData = try JSONSerialization.data(withJSONObject: payload)
        guard let req = String(data: reqData, encoding: .utf8) else {
            throw InvokeError(message: "encode invoke request")
        }
        let respStr = LibXrayInvoke(req)
        guard let respData = respStr.data(using: .utf8),
              let obj = try JSONSerialization.jsonObject(with: respData) as? [String: Any]
        else {
            throw InvokeError(message: "decode invoke response")
        }
        let ok = obj["success"] as? Bool ?? false
        if !ok {
            throw InvokeError(message: (obj["error"] as? String) ?? "LibXray error")
        }
        return obj["data"] as? [String: Any]
    }
}