/*
 * This file is part of GNU Taler
 * (C) 2020 Taler Systems S.A.
 *
 * GNU Taler is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 3, or (at your option) any later version.
 *
 * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */

package net.taler.merchantlib

import io.ktor.client.HttpClient
import io.ktor.client.engine.mock.MockEngine
import io.ktor.client.engine.mock.MockEngineConfig
import io.ktor.client.engine.mock.respond
import io.ktor.client.plugins.contentnegotiation.ContentNegotiation
import io.ktor.http.ContentType.Application.Json
import io.ktor.http.HttpStatusCode
import io.ktor.http.Url
import io.ktor.http.content.TextContent
import io.ktor.http.fullPath
import io.ktor.http.headersOf
import io.ktor.http.hostWithPort
import io.ktor.serialization.kotlinx.json.json
import kotlinx.serialization.json.Json
import kotlinx.serialization.json.Json.Default.parseToJsonElement
import org.junit.Assert.assertEquals

object MockHttpClient {

    val httpClient = HttpClient(MockEngine) {
        engine {
            addHandler { error("No response handler set") }
        }
        expectSuccess = true
        install(ContentNegotiation) {
            json(Json {
                encodeDefaults = false
                ignoreUnknownKeys = true
            })
        }
    }

    fun HttpClient.giveJsonResponse(
        url: String,
        expectedBody: String? = null,
        statusCode: HttpStatusCode = HttpStatusCode.OK,
        jsonProducer: () -> String,
    ) {
        val httpConfig = engineConfig as MockEngineConfig
        httpConfig.requestHandlers.removeAt(0)
        httpConfig.requestHandlers.add { request ->
            if (request.url.fullUrl == url) {
                val headers = headersOf("Content-Type" to listOf(Json.toString()))
                if (expectedBody != null) {
                    val content = request.body as TextContent
                    assertJsonEquals(expectedBody, content.text)
                }
                respond(jsonProducer(), headers = headers, status = statusCode)
            } else {
                error("Unexpected URL: ${request.url.fullUrl}")
            }
        }
    }

    private val Url.hostWithPortIfRequired: String get() = if (port == protocol.defaultPort) host else hostWithPort
    private val Url.fullUrl: String get() = "${protocol.name}://$hostWithPortIfRequired$fullPath"

    private fun assertJsonEquals(json1: String, json2: String) {
        val parsed1 = parseToJsonElement(json1)
        val parsed2 = parseToJsonElement(json2)
        assertEquals(parsed1, parsed2)
    }

}