roomescape-refactored/src/main/kotlin/roomescape/common/log/ApiLogMessageConverter.kt

package roomescape.common.log

import com.fasterxml.jackson.databind.ObjectMapper
import jakarta.servlet.http.HttpServletRequest
import org.slf4j.MDC

enum class LogType {
    INCOMING_HTTP_REQUEST,
    CONTROLLER_INVOKED,
    CONTROLLER_SUCCESS,
    AUTHENTICATION_FAILURE,
    APPLICATION_FAILURE,
    UNHANDLED_EXCEPTION
}

class ApiLogMessageConverter(
    private val objectMapper: ObjectMapper
) {
    fun convertToHttpRequestMessage(
        request: HttpServletRequest
    ): String {
        val payload: MutableMap<String, Any> = commonRequestPayload(LogType.INCOMING_HTTP_REQUEST, request)

        request.queryString?.let { payload["query_params"] = it }
        payload["client_ip"] = request.remoteAddr
        payload["user_agent"] = request.getHeader("User-Agent")

        return objectMapper.writeValueAsString(payload)
    }

    fun convertToControllerInvokedMessage(
        request: HttpServletRequest,
        controllerPayload: Map<String, Any>,
    ): String {
        val payload: MutableMap<String, Any> = commonRequestPayload(LogType.CONTROLLER_INVOKED, request)
        val memberId: Long? = MDC.get("member_id")?.toLong()
        if (memberId != null) payload["member_id"] = memberId else payload["member_id"] = "NONE"

        payload.putAll(controllerPayload)

        return objectMapper.writeValueAsString(payload)
    }

    fun convertToResponseMessage(request: ConvertResponseMessageRequest): String {
        val payload: MutableMap<String, Any> = mutableMapOf()
        payload["type"] = request.type
        payload["status_code"] = request.httpStatus

        MDC.get("member_id")?.toLongOrNull()
            ?.let { payload["member_id"] = it }
            ?: run { payload["member_id"] = "NONE" }

        request.startTime?.let { payload["duration_ms"] = System.currentTimeMillis() - it }
        request.body?.let { payload["response_body"] = it }
        request.exception?.let {
            payload["exception"] = mapOf(
                "class" to it.javaClass.simpleName,
                "message" to it.message
            )
        }

        return objectMapper.writeValueAsString(payload)
    }

    private fun commonRequestPayload(
        logType: LogType,
        request: HttpServletRequest
    ): MutableMap<String, Any> = mutableMapOf(
        "type" to logType,
        "method" to request.method,
        "uri" to request.requestURI
    )
}

data class ConvertResponseMessageRequest(
    val type: LogType,
    val httpStatus: Int = 200,
    val startTime: Long? = null,
    val body: Any? = null,
    val exception: Exception? = null
)