package com.example.gudariwallet.util

import org.json.JSONArray

/**
 * Stateless helpers for parsing LNURL-pay step-1 metadata fields.
 * Shared between [com.example.gudariwallet.data.LNbitsWalletRepository]
 * and [com.example.gudariwallet.ui.WalletViewModel] so neither duplicates
 * the logic.
 */
object LnurlMetadataParser {

    /**
     * Extracts the `text/plain` description from a LNURL-pay metadata JSON string.
     * The metadata field is a JSON array of [type, value] pairs, e.g.:
     *   [["text/plain","Pay me"],["image/png;base64","..."]]
     * Returns an empty string if the field is null, blank, or unparseable.
     */
    fun parseDescription(metadata: String?): String {
        if (metadata.isNullOrBlank()) return ""
        return runCatching {
            val array = JSONArray(metadata)
            (0 until array.length())
                .map { array.getJSONArray(it) }
                .firstOrNull { it.getString(0) == "text/plain" }
                ?.getString(1) ?: ""
        }.getOrDefault("")
    }

    /**
     * Extracts the host portion of [callback] for display purposes.
     * Returns an empty string if [callback] is null, blank, or not a valid URI.
     */
    fun extractDomain(callback: String?): String {
        if (callback.isNullOrBlank()) return ""
        return runCatching { java.net.URI(callback).host ?: "" }.getOrDefault("")
    }
}

/**
 * Returns the display label for a LNURL payment target.
 * If [lnurl] is a Lightning Address (contains '@'), returns it as-is.
 * Otherwise returns the [domain] of the LNURL endpoint.
 */
fun payingToLabel(lnurl: String, domain: String): String =
    if ('@' in lnurl) lnurl else domain