rcdbquery/src/main/kotlin/de/pheerai/rcdbquery/dsl/rcdbQueryDsl.kt

package de.pheerai.rcdbquery.dsl

import de.pheerai.rcdbquery.dataMappings.internal.RcdbParamOption
import de.pheerai.rcdbquery.dataMappings.searchType.SearchType

// TODO: Restructure

data class RcdbParams(
    val multiParams: MultiParams,
    val singleParams: SingleParams
) {
    fun toStrings(): List<String> {
        val multiParamSequence: Sequence<Pair<String, String>> = this.multiParams
            .params
            .asSequence()
            .map { e -> e.key to e.value.joinToString(separator = ",") }
        val singleParamSequence: Sequence<Pair<String, String>> = this.singleParams
            .params
            .asSequence()
            .map { it.toPair() }
        return singleParamSequence.plus(multiParamSequence)
            .map { p -> "${p.first}=${p.second}" }
            .toList()
    }
}

sealed class Params<T> {
    abstract val params: Map<String, T>
}

class ParamAlreadySetException(message: String) : IllegalArgumentException(message)

class MultiParams(override val params: Map<String, List<String>>) : Params<List<String>>()
class SingleParams(override val params: Map<String, String>) : Params<String>()

class ParamsCollector {
    private val multiParams: MutableMap<String, List<RcdbParamOption<Any>>> = mutableMapOf()
    private val singleParams: MutableMap<String, RcdbParamOption<Any>> = mutableMapOf()

    fun build() = RcdbParams(buildMulti(), buildSingle())

    /**
     * Creates the Query Params from this builder.
     * If no Search type has been set, this will default to "Coaster"
     */
    private fun buildMulti() = multiParams.apply {
            // Defaults go here, if any
        }
        .filter { it.value.isNotEmpty() }
        .mapValues { e -> e.value.map { o -> o.paramValue.toString() } }
        .let { MultiParams(it) }

    private fun buildSingle() = singleParams.apply {
            putIfAbsent(SearchType.paramKey, SearchType.COASTER)
        }
        .mapValues { e -> e.value.paramValue.toString() }
        .let { SingleParams(it) }

    operator fun set(paramName: String, options: List<RcdbParamOption<Any>>) {
        this.multiParams[paramName] = options
    }

    operator fun set(paramName: String, option: RcdbParamOption<Any>) {
        if (paramName !in singleParams && paramName !in multiParams) {
            this.singleParams[paramName] = option
        } else {
            throw ParamAlreadySetException("Parameter $paramName already set.")
        }
    }

    fun getSingle(paramName: String) = this.multiParams[paramName] ?: this.singleParams[paramName]
    fun getMulti(paramName: String) = this.multiParams[paramName]

    fun keys() = this.multiKeys().plus(singleKeys())
    private fun multiKeys() = this.multiParams.keys.toSet()
    private fun singleKeys() = this.singleParams.keys.toSet()
}

fun rcdbQuery(body: ParamsCollector.() -> ParamsCollector) =
    RcdbUrlQuery("https://www.rcdb.com/r.htm?", rcdbQueryParams(body)).toString()

data class RcdbUrlQuery(val baseUrl: String, val params: RcdbParams) {
    override fun toString(): String {
        return params.toStrings()
            .joinToString(prefix = baseUrl, separator = "&")
    }
}

/**
 * Builder for the parameters only (mainly because it might be possilbe in the future to have an API with a POST search object?
 */
fun rcdbQueryParams(body: ParamsCollector.() -> ParamsCollector): RcdbParams {
    val builder = ParamsCollector()
    builder.body()
    return builder.build()
}