package com.sptmobile.browse

import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow

/**
 * Human labels for the phone's paired gateways, keyed by the host's **paired
 * node key** (the device-link iroh key in `PairedHost.node`, ADR-0002) — which
 * is NOT the host's spt node. The label the user wants (`mobile-gw @ HFENDULEAM`)
 * is the spt-node the gateway actually runs on, so it can't be looked up by the
 * device-link key directly.
 *
 * [resolve] bridges the two: in a host's own `listEndpoints` reply, the gateway
 * endpoint (id == the host's endpoint) appears on the host's spt node, carrying
 * that node's `node_label`. We map device-link key → that spt-node label (and
 * spt node key, for home-first ordering). The GUI shows labels, never hashes.
 */
object NodeLabels {
    /** paired (device-link) node key → its gateway's spt-node label. */
    private val _labels = MutableStateFlow<Map<String, String>>(emptyMap())
    val labels: StateFlow<Map<String, String>> = _labels

    /** paired (device-link) node key → the spt node its gateway runs on. */
    private val _sptNodes = MutableStateFlow<Map<String, String>>(emptyMap())
    val sptNodes: StateFlow<Map<String, String>> = _sptNodes

    /**
     * Learn a paired host's spt-node label + key from its OWN listing. [reply]
     * is that host's `listEndpoints` JSON; [hostEndpoint] its gateway endpoint
     * id (e.g. `mobile-gw`); [pairedNode] the device-link key it's keyed by.
     */
    fun resolve(pairedNode: String, hostEndpoint: String, reply: String) {
        val ep = try {
            EndpointDirectory.parseHostReply(reply).asSequence()
                .flatMap { it.endpoints.asSequence() }
                .firstOrNull { it.id == hostEndpoint && it.node_label != null }
        } catch (_: IllegalArgumentException) {
            null
        } ?: return
        val label = ep.node_label ?: return
        if (_labels.value[pairedNode] != label) {
            _labels.value = _labels.value + (pairedNode to label)
        }
        if (_sptNodes.value[pairedNode] != ep.node) {
            _sptNodes.value = _sptNodes.value + (pairedNode to ep.node)
        }
    }
}