package com.jttools.datacontrol.remote

import org.json.JSONArray
import org.json.JSONObject
import java.net.URI
import java.net.URLDecoder

/**
 * Liaison avec le serveur familyd, reçue à l'appairage (sans les secrets : jeton de l'appareil et clé
 * privée WireGuard sont stockés à part, chiffrés par l'Android Keystore, voir SecretBox).
 */
data class FamilyLink(
    val serverUrl: String,
    val deviceId: String,
    val name: String,
    val address: String,
    val dns: String,
    val mtu: Int,
    val serverPublicKey: String,
    val endpoint: String,
    val allowedIps: List<String>,
    val keepalive: Int,
    val apiBase: String
) {
    /** Adresse du téléphone dans le tunnel, sans le /32. */
    val tunnelIp: String get() = address.substringBefore('/')

    fun toJson(): String = JSONObject()
        .put("serverUrl", serverUrl).put("deviceId", deviceId).put("name", name)
        .put("address", address).put("dns", dns).put("mtu", mtu)
        .put("serverPublicKey", serverPublicKey).put("endpoint", endpoint)
        .put("allowedIps", JSONArray(allowedIps)).put("keepalive", keepalive).put("apiBase", apiBase)
        .toString()

    /** Configuration WireGuard au format wg-quick (lue par la bibliothèque officielle). */
    fun wgQuickConfig(privateKey: String): String = buildString {
        appendLine("[Interface]")
        appendLine("PrivateKey = $privateKey")
        appendLine("Address = $address")
        appendLine("DNS = $dns")
        appendLine("MTU = $mtu")
        appendLine()
        appendLine("[Peer]")
        appendLine("PublicKey = $serverPublicKey")
        appendLine("Endpoint = $endpoint")
        appendLine("AllowedIPs = ${allowedIps.joinToString(", ")}")
        appendLine("PersistentKeepalive = $keepalive")
    }

    companion object {
        fun fromJson(json: String?): FamilyLink? {
            if (json.isNullOrBlank()) return null
            return runCatching {
                val o = JSONObject(json)
                val ips = o.getJSONArray("allowedIps")
                FamilyLink(
                    serverUrl = o.getString("serverUrl"), deviceId = o.getString("deviceId"),
                    name = o.optString("name"), address = o.getString("address"), dns = o.getString("dns"),
                    mtu = o.optInt("mtu", 1280), serverPublicKey = o.getString("serverPublicKey"),
                    endpoint = o.getString("endpoint"),
                    allowedIps = (0 until ips.length()).map { ips.getString(it) },
                    keepalive = o.optInt("keepalive", 25), apiBase = o.getString("apiBase")
                )
            }.getOrNull()
        }

        /** Réponse de POST /api/pair → liaison + jeton de l'appareil. */
        fun fromPairResponse(serverUrl: String, json: String): Pair<FamilyLink, String> {
            val o = JSONObject(json)
            val wg = o.getJSONObject("wireguard")
            val ips = wg.getJSONArray("allowed_ips")
            val link = FamilyLink(
                serverUrl = serverUrl, deviceId = o.getString("device_id"), name = o.optString("name"),
                address = wg.getString("address"), dns = wg.getString("dns"), mtu = wg.optInt("mtu", 1280),
                serverPublicKey = wg.getString("server_public_key"), endpoint = wg.getString("endpoint"),
                allowedIps = (0 until ips.length()).map { ips.getString(it) },
                keepalive = wg.optInt("persistent_keepalive", 25), apiBase = o.getString("api").trimEnd('/')
            )
            require(link.serverPublicKey.isNotBlank()) { "Le serveur n'a pas fourni sa clé WireGuard." }
            return link to o.getString("token")
        }
    }
}

/**
 * Ce que l'utilisateur saisit pour s'associer : le code seul (« ABCD 2345 »), ou le lien
 * « familyd://pair?url=https://…&code=… » affiché par l'interface des parents.
 */
data class PairingInput(val serverUrl: String, val code: String) {
    companion object {
        const val DEFAULT_SERVER = "https://family.tuxtech.fr"
        private val CODE = Regex("^[A-HJ-NP-Z2-9]{8}$")   // même alphabet que le serveur (sans I, O, 0, 1)

        fun parse(input: String, defaultServer: String = DEFAULT_SERVER): PairingInput? {
            val text = input.trim()
            if (text.startsWith("familyd://", ignoreCase = true)) {
                val query = runCatching { URI(text).rawQuery }.getOrNull() ?: return null
                val params = query.split('&').mapNotNull {
                    val (k, v) = it.split('=', limit = 2).takeIf { p -> p.size == 2 } ?: return@mapNotNull null
                    k to URLDecoder.decode(v, "UTF-8")
                }.toMap()
                val url = params["url"]?.trimEnd('/') ?: return null
                val code = normalize(params["code"] ?: return null) ?: return null
                if (!url.startsWith("https://")) return null
                return PairingInput(url, code)
            }
            return normalize(text)?.let { PairingInput(defaultServer, it) }
        }

        private fun normalize(code: String): String? =
            code.uppercase().replace(" ", "").replace("-", "").takeIf { CODE.matches(it) }
    }
}