initial commit: demo: shows contratcs, checks ids or contracts.

.gitignore

@@ -0,0 +1,48 @@
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### IntelliJ IDEA ###
+.idea/modules.xml
+.idea/jarRepositories.xml
+.idea/compiler.xml
+.idea/libraries/
+*.iws
+*.iml
+*.ipr
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### Kotlin ###
+.kotlin
+
+### Eclipse ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+bin/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store
+/test_contracts/
+.idea
+

.idea/.gitignore

@@ -0,0 +1,3 @@
+# Default ignored files
+/shelf/
+/workspace.xml

.idea/codeStyles/Project.xml

@@ -0,0 +1,7 @@
+<component name="ProjectCodeStyleConfiguration">
+  <code_scheme name="Project" version="173">
+    <ScalaCodeStyleSettings>
+      <option name="MULTILINE_STRING_CLOSING_QUOTES_ON_NEW_LINE" value="true" />
+    </ScalaCodeStyleSettings>
+  </code_scheme>
+</component>

.idea/codeStyles/codeStyleConfig.xml

@@ -0,0 +1,5 @@
+<component name="ProjectCodeStyleConfiguration">
+  <state>
+    <option name="PREFERRED_PROJECT_CODE_STYLE" value="Default" />
+  </state>
+</component>

.idea/gradle.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="GradleMigrationSettings" migrationVersion="1" />
+  <component name="GradleSettings">
+    <option name="linkedExternalProjectsSettings">
+      <GradleProjectSettings>
+        <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="gradleHome" value="" />
+        <option name="modules">
+          <set>
+            <option value="$PROJECT_DIR$" />
+          </set>
+        </option>
+      </GradleProjectSettings>
+    </option>
+  </component>
+</project>

.idea/kotlinc.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="KotlinJpsPluginSettings">
+    <option name="version" value="2.0.10" />
+  </component>
+</project>

.idea/misc.xml

@@ -0,0 +1,6 @@
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_17" default="true" project-jdk-name="17 (2)" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

REAMDE.md

@@ -0,0 +1,62 @@
+# INDIGO DEMO command line tool
+
+This demo shows how to connect to the private Universa network, check the contract ID for network approval,
+load binary contract file, show some of its information and check its network status.
+
+## Some details
+
+File [indigo_demo_2025.json](src/main/resources/topologies/indigo_demo_2025.json)
+contains actual private network configuration.
+
+[Main.kt](src/main/kotlin/Main.kt) is a simple CLI tool that does it all.
+
+Source [Uni.kt](src/main/kotlin/Uni.kt) contains a simple connection pool for universa
+clients to run in parallel with coroutines.
+
+## Contract IDs and Files
+
+When using INDIGO demo, see [History](https://indigo.8-rays.dev/operations). In the
+operations history you can see contracts binary and in text form (some key fields for the demo).
+
+You can also copy the contract ID (click on it in the `contract` line) or download its binary.
+
+Both can be used with this tool to show and check network status.
+
+## Important note on contract approval states
+
+Contracts, taken from the INDIGO, are not necessarily approved. For example, when you transfer funds, or pay invoices, some of the coin contracts will be modified, so old versions, presented in the logs, will not be approved anymore. This is quite normal and is a core feature of the Universa network.
+
+## Usage sample
+
+If you have binary distribution built with gradle task `./gradlew installDist`, you can
+run it from a console. Alternatively, you can download, unpack and run the same the prebuilt demo: [indigo_demo_sample.zip](prebuilt_demo/indigo_demo_sample.zip).
+
+```
+build/install/indigo_demo_sample/bin/indigo_demo_sample -c test_contracts/indigo_2025-04-14T20-22-45.962Z.unicon
+
+INDIGO sample console tool
+
+Connecting to Universa network...
+Connected. Here is the list of nodes:
+http://31.41.155.11:8080 or https://31.41.155.11: J4ePqUDVy9Tj2n5pV9UCMxR1qhxS7eHMbUNzRXA6SEcwRF6kSNf5j1mDV9gbVnrk41Lwy2FY
+http://37.9.5.102:8080 or https://37.9.5.102: JCi984dnqdgGq3YkYgLqbQKciMRqVhaE5hLSBi8vcfsNKw2KTR63ATCSfokBZ46wLT13PYag
+http://37.9.4.133:8080 or https://37.9.4.133: J2ryG4uxnZxDUUoE8fz1ioPsdWcbwMkUMcZju6ZTpSTFJjF11Kd1Wn23DRrREbgxRNjq13BK
+http://37.9.4.137:8080 or https://37.9.4.137: JfcHBZ4Wicj4t9YuTZDsKXsGGWstTgpftt7fnrWiro2hchNy2F9sHLT4x6RWDs8Hrh5EZyAq
+
+Loaded contract: A0tD/Zc3QZ/hxfAESHb4C+Mzsd6VWRqVh4SMouplq7WfH9qUaaDZwgFS4DdVglhu4ks2raGPWYcgfsPfkxyg4i3sm9wiDIiR/VnwQ8v6GqeVVED6TOp8kSERpJFyCYRK
+Definition ---------------------------------------------- 
+Created   : 2025-04-05T02:24:48+03:00[Europe/Moscow]
+Expires   : 2030-04-05T02:24:48+03:00[Europe/Moscow]
+Ext.type  : null
+Definition: {short_currency=TINDIGO, name=IndigoTest, description=Indigo test token, currency=TINDIGO}
+State --------------------------------------------------- 
+Revision : 1
+Branch   : null/0
+State data    : {amount=5.0E+2}
+Transactional -------------------------------------------
+data: {}
+
+Checking contract Id: A0tD/Zc3…: Rejected
+```
+
+See above for the actual contracts.

build.gradle.kts

@@ -0,0 +1,44 @@
+plugins {
+    kotlin("jvm") version "2.0.10"
+    application
+}
+
+group = "net.sergeych"
+version = "1.0-SNAPSHOT"
+
+repositories {
+    mavenCentral()
+    maven("https://maven.universablockchain.com")
+}
+
+application {
+    mainClass.set("net.sergeych.MainKt")
+}
+
+dependencies {
+    implementation("com.icodici:universa_core:3.14.7")
+    implementation("net.sergeych:unikrypto:1.2.5-SNAPSHOT")
+
+    testImplementation(kotlin("test"))
+}
+
+tasks.test {
+    useJUnitPlatform()
+}
+
+kotlin {
+    jvmToolchain(17)
+}
+
+tasks.register<Jar>("fatJar") {
+    archiveBaseName.set("my-console-app") // Change to your desired JAR name
+    manifest {
+        attributes["Main-Class"] = application.mainClass.get() // Set the main class
+    }
+    from(configurations.runtimeClasspath.get().map { if (it.isDirectory) it else zipTree(it) }) // Include dependencies
+    with(tasks.jar.get() as CopySpec) // Include the default jar contents
+}
+
+tasks.build {
+    dependsOn(tasks.named("fatJar")) // Ensure fatJar is built with the build task
+}

gradle.properties

@@ -0,0 +1 @@
+kotlin.code.style=official

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Sun Apr 13 16:13:31 MSK 2025
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.8-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,234 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle.kts

@@ -0,0 +1,5 @@
+plugins {
+    id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
+}
+rootProject.name = "indigo_demo_sample"
+

src/main/kotlin/Main.kt

@@ -0,0 +1,85 @@
+package net.sergeych
+
+import com.icodici.universa.HashId
+import com.icodici.universa.contract.TransactionPack
+import kotlinx.coroutines.runBlocking
+import net.sergeych.uni.Uni
+import java.io.File
+
+fun main(_args: Array<String>) {
+    val args = _args.toMutableList()
+
+    println("\nINDIGO sample console tool\n")
+//    val args = mutableListOf("-c", "???")
+    runBlocking {
+        println("Connecting to Universa network...")
+
+        // connect to the network and print out nodes info
+        Uni.versa {
+            println("Connected. Here is the list of nodes:")
+            topologyInfo.forEach {
+                println("${it.ipUrl} or ${it.domainUrl}: ${it.keyAddress}")
+            }
+        }
+        while (args.isNotEmpty()) {
+            if (args[0] == "-h") {
+                println("\nUsage:")
+                println("  -c <contractID | contractFile> - check contract approval")
+                println("  -h - this help")
+                break
+            }
+            processCheckContract(args)
+        }
+        // universa client runs background coroutines here, so we shall cancel them
+        System.exit(0)
+    }
+}
+
+/**
+ * if args start with "-c", checks the contractId or loads the contract using args[1]
+ * and checks network approval, and remove both arguments from args array.
+ */
+suspend fun processCheckContract(args: MutableList<String>) {
+    if (args[0] == "-c") {
+        val contractId = if (args[1].endsWith(".unicon")) {
+            // got a file, load it using TransactionPack format (common for contracts):
+            val c = TransactionPack.unpack(
+                File(args[1]).readBytes()
+            )
+                // and extract its main contract:
+                .contract
+
+            println("\nLoaded contract: ${c.id.toBase64String()}")
+            println("Definition ---------------------------------------------- ")
+            println("Created   : ${c.definition.createdAt}")
+            println("Expires   : ${c.definition.expiresAt}")
+            println("Ext.type  : ${c.definition.extendedType}")
+            println("Definition: ${c.definition.data}")
+            println("State --------------------------------------------------- ")
+            println("Revision : ${c.state.revision}")
+            println("Branch   : ${c.state.branchId}/${c.state.branchRevision}")
+            println("State data    : ${c.state.data}")
+
+            if( c.transactional != null ) {
+                println("Transactional -------------------------------------------")
+                println("data: ${c.transactional!!.data}")
+            }
+
+            // return its id for further checks:
+            c.id
+        } else
+            HashId.withDigest(args[1])
+
+        // -c <contract-id | contract-file>
+        // remove arguments
+        args.removeAt(0)
+        args.removeAt(0)
+
+        // check contract approval from the universa network:
+        print("\nChecking contract Id: $contractId: ")
+
+        val isApproved = Uni.versa { isApprovedByNetwork(contractId) }
+
+        println(if (isApproved) "Approved" else "Rejected")
+    }
+}

src/main/kotlin/Uni.kt

@@ -0,0 +1,191 @@
+package net.sergeych.uni
+
+import com.icodici.crypto.PrivateKey
+import com.icodici.crypto.PublicKey
+import com.icodici.universa.ErrorRecord
+import com.icodici.universa.HashId
+import com.icodici.universa.node.ItemState
+import com.icodici.universa.node2.network.Client
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import net.sergeych.mp_logger.LogTag
+import net.sergeych.mp_logger.exception
+import net.sergeych.mp_logger.info
+import net.sergeych.mp_logger.warning
+import net.sergeych.mp_tools.decodeBase64
+import java.io.File
+
+
+/**
+ * This is a rather simple connection pool for the threaded Universa clients
+ * to use with Kotlin coroutines.
+ *
+ * Uni pool is needed as Universa's client is blocking old-school Java code, and to
+ * use it with coroutines th pool is needed.
+ *
+ * Note that you can use Universa JAVA API directly. Also, indigo project uses multiplatform
+ * library that works now on JS and JVM the same way. It will be made public on release.
+ */
+object Uni : LogTag("UNI") {
+
+    // How many worker clients to use
+    val Parallelism = 2
+
+    // name of the topology file in resources/topologies, see source tree.
+    // it must not differ too much from the network (small changes are ok)
+    val NetworkName = "indigo_demo_2025"
+
+    /**
+     * The client's private key. We use "white" key that allows to execute paid operations
+     * for free. This is usual for private networks.
+     */
+    private val key = PrivateKey(
+        File("./white.private.unikey")
+            .readBytes()
+    )
+
+    /**
+     * The number of allocated clients
+     */
+    var allocated = 0
+        private set
+
+    // clients pool
+    private val pool = Channel<Context>(Parallelism)
+
+    // mutex to guard pool access
+    private val access = Mutex()
+
+    /**
+     * Get a client from the pool or allocate a new one, and execute [f] in it's
+     * context.
+     */
+    suspend fun <T> versa(f: suspend Context.() -> T): T {
+        val x = access.withLock {
+            pool.tryReceive().getOrNull()
+                ?: run {
+                    if (allocated < Parallelism) {
+                        info { "Allocating new client, currenly there are $allocated" }
+                        Context.connect(NetworkName, key).also { allocated++ }.also {
+                            info { "Allocated new client, currenly there are $allocated" }
+                        }
+                    } else null
+                }
+        } ?: pool.receive()
+        return try {
+            x.f().also {
+                access.withLock { pool.send(x) }
+            }
+        } catch (t: IllegalStateException) {
+            warning { "Critical exception, will re-connect the client: $t" }
+            allocated--
+            throw t
+        } catch (t: Throwable) {
+            exception { "unexpected in UNI to t" to t }
+            access.withLock { pool.send(x) }
+            throw t
+        }
+    }
+
+    /**
+     * Kotlin wrapper for the Universa's java based registration result.
+     */
+    sealed class URegistrationResult {
+
+        /**
+         * true if the registration is approved by the network
+         */
+        @Suppress("unused")
+        val approved by lazy {
+            this is Approved
+        }
+
+        /**
+         * Approved state, with extended [state] information
+         */
+        data class Approved(val state: ItemState) : URegistrationResult() {
+            override fun toString(): String {
+                return state.toString()
+            }
+        }
+
+        /**
+         * Rejected state, with extended [state] information and list of [errors]
+         * as reported by the network node.
+         */
+        class Rejected(
+            val errors: List<ErrorRecord>,
+            val state: ItemState,
+        ) : URegistrationResult() {
+            override fun toString(): String {
+                return "$state: ${errors.joinToString(", ")}"
+            }
+        }
+    }
+
+    /**
+     * Context is a wrapper for the Universa's java based client to be used
+     * with [Uni] pool and Kotlin coroutines.
+     */
+    class Context(private val c: Client) {
+
+        data class TopologyInfo(
+            val nodeNumber: Int,
+            val ipUrl: String,
+            val domainUrl: String,
+            val keyAddress: String,
+        )
+
+        /**
+         * Current network topology (configuration): urls, node numbers,
+         * public keys, etc.
+         */
+        val topologyInfo by lazy {
+            c.topology.map {
+                TopologyInfo(
+                    it.getIntOrThrow("number"),
+                    it.getArray("direct_urls").first() as String,
+                    it.getArray("domain_urls").first() as String,
+                    PublicKey(it.getStringOrThrow("key").decodeBase64()).longAddress.toString()
+                )
+            }
+        }
+
+        /**
+         * Register a Universa TransactionPack with one or more contracts.
+         * It polls the network until the consensus will be reached.
+         */
+        @Suppress("unused")
+        fun register(packed: ByteArray): URegistrationResult {
+            while (true) {
+                val ir = c.register(packed, 30_000)
+                val state = ir.state
+                if (state.isPending) continue
+                if (state.isApproved) return URegistrationResult.Approved(state)
+                else return URegistrationResult.Rejected(ir.errors, state)
+            }
+        }
+
+        /**
+         * Check that qualified majority of the network has approved the contract
+         * with [contractId]
+         * @param threshold is a percentage of the network size, default is 40%
+         * @return true if the contract is approved by the network
+         */
+        fun isApprovedByNetwork(contractId: HashId, threshold: Double = 0.4): Boolean {
+            return c.isApprovedByNetwork(contractId, threshold, 15_000)
+        }
+
+        companion object {
+            /**
+             * Create a new client and connect to the network. This is not used directly
+             * mostly, but is used by [Uni] pool.
+             */
+            fun connect(networkName: String, key: PrivateKey): Context {
+                val c = Client(networkName, null, key)
+                return Context(c)
+            }
+        }
+    }
+}

src/main/resources/topologies/indigo_demo_2025.json

@@ -0,0 +1,49 @@
+{
+  "list": [
+    {
+      "number": 1,
+      "domain_urls": [
+        "https://31.41.155.11"
+      ],
+      "name": "node-01",
+      "direct_urls": [
+        "http://31.41.155.11:8080"
+      ],
+      "key": "HggcAQABxAAB5IfycVepakIjOt3c5eyLFswYH8dokrmHTyRIgaCSz+EY+mm8hM2Cn1PJjyiJj4K1A8CPN9p9mj6z/yyGSH6pvW3HMGs6Az7KvhGbZJlsFP0tNy6A3YQEWP/XToSqtT3f0Ji/r2nYw2zEgnGvOBkkcyN/EEslnxTj1R3fZlaSHh9Uem6NFk62ZxSBj8hJkvfHbTB/XZ2z8wtpwcAJClylITbbCSg9RdXoD8ZwCJMaCWasxfdo5+sMYTcABYFErbw8ndeQ5aL3N2+XiFM8WO5wQnd3SNTYUQGucBkXO5zqmZjnreVOWIsQtKzjwH4WIi57kz+87V72TbDrX0jYMYsOSw=="
+    },
+    {
+      "number": 2,
+      "domain_urls": [
+        "https://37.9.5.102"
+      ],
+      "name": "node-02",
+      "direct_urls": [
+        "http://37.9.5.102:8080"
+      ],
+      "key": "HggcAQABxAAB3GST2bRm2SrwypfKZRplqDwLUvDF7DoRgVMZfzOHzYodHfIpNrRKZfJdr63UdpK6359G1TAAHm52UaLCaCqBZNuFDqE9s9fEe+2UoSzoMKGG0NtgFD2HdDhuNWw4LnqZiZ5lPlZuUKtxVCzhlI0SNweBKMn0oopjdOYfx7hkPHVB2TyADXPrcnxFHEpc6USjJgP3aHPgum4CxYD09KTF59t5W+B+rDpTd/ro3ENBSFi9xlt4qMrLx5KzIdm8IqcsEm+mTYS5mx0F4e6wlCiXElwGe1NdXNwb/A8S2JBSUKP2CfSKdJtB0D7GHFnMuF3+u29/pykBOvlUoUa4S5QxJQ=="
+    },
+    {
+      "number": 3,
+      "domain_urls": [
+        "https://37.9.4.133"
+      ],
+      "name": "node-03",
+      "direct_urls": [
+        "http://37.9.4.133:8080"
+      ],
+      "key": "HggcAQABxAABtTajk8wkzstB+mmj09fkP/a9IqX4tVuuXnd/fO6a3TAjNbulqtkvVyfhu2DeUdUFiYP9kc+YQmHsIe5T/xZgdecWAbHKT0Ok530nLju8dog+75j6aCqD+winCCb+s7dzAYNIsKS0QgBPPWyBUyDL+di17s2Z5U2mibV+sXQYfWU4Gy02WNuavC8QZ0gA7K3Ah6ohR/Yn37WpiWvS+kQOnZF/q/8LYRQgxdDrztzTgpouggwk/1VJ181fYcXq/54n+L5yV2M0GZy7B942ce07MV6EGmQJu4eoOQi8DN3Ee30WOuIIiEyiQLMJjva0uxvkXmlftsr8rGiLXB+kiMd2fQ=="
+    },
+    {
+      "number": 4,
+      "domain_urls": [
+        "https://37.9.4.137"
+      ],
+      "name": "node-04",
+      "direct_urls": [
+        "http://37.9.4.137:8080"
+      ],
+      "key": "HggcAQABxAABkGzNgQnnNh/aNR3zQujD/6mgcqqfZ3tl14DDLhXLunUhc8hkn3y+ViukIj1qbkPi6Ps5irDZ2TzVfepoVWqX+XkI8wUbXKpDN/zWYx9kW4/soA4C7KS6fS/NFsFflUyzDNQeQXmiQkPTNnn43sdSqYb6Zr3I7Wa6mEwIP7MakKo6SbJQ/gTdXPlKWnU1nGJISMowCfhawYQLZgI5URsgS3VV7Owb3Yo4IZ0YNDTceboY4ljYuc/R2LqJcGjcWfSweaHV2T64RY6yQt1W0h2KweK99cflJdh/QSCqBhRdSYYfgKDlmp2ZTvrrfj0bbz2mPBh5JG5RQe+O9MzT0Is4ew=="
+    }
+  ],
+  "updated": 1742911675
+}