// Example 03 — Multi-Output (Fan-Out)
//
// A single "parse" node reads "KEY=VALUE" strings and fans out to two
// independent downstream sinks — one for keys, one for values.
//
//                              +--> [print_key]
//  [generate] --string--> [parse]
//                              +--> [print_value]
//
// The parser returns std::tuple<std::string, std::string>.
// Network::connect() routes each element of the tuple to a different node.

#include <kpn/kpn.hpp>
#include <chrono>
#include <iostream>
#include <string>
#include <thread>
#include <tuple>

// ── Node functions ────────────────────────────────────────────────────────────

static int gen_index = 0;

static std::string generate() {
    static const char* pairs[] = {
        "host=localhost",
        "port=8080",
        "timeout=30s",
        "retries=3",
        "protocol=http2",
    };
    std::this_thread::sleep_for(std::chrono::milliseconds(60));
    return pairs[gen_index++ % 5];
}

// Multi-output: returns (key, value) as a tuple — KPN++ routes each element
// to its own output port automatically.
static std::tuple<std::string, std::string> parse(std::string kv) {
    auto sep = kv.find('=');
    if (sep == std::string::npos) return {kv, ""};
    return {kv.substr(0, sep), kv.substr(sep + 1)};
}

static void print_key(std::string key) {
    std::cout << "KEY   → " << key << '\n';
}

static void print_value(std::string value) {
    std::cout << "VALUE → " << value << '\n';
}

// ── main ──────────────────────────────────────────────────────────────────────

int main() {
    using namespace kpn;

    auto gen  = make_node<generate>(out<"kv">{},          4);
    auto par  = make_node<parse>   (in<"kv">{},  out<"key", "value">{}, 4);
    auto keys = make_node<print_key>  (in<"key">{},   4);
    auto vals = make_node<print_value>(in<"value">{}, 4);

    Network net;
    net.add("gen",  gen)
       .add("par",  par)
       .add("keys", keys)
       .add("vals", vals)
       .connect("gen",  gen.template output<"kv">(),    "par",  par.template input<"kv">())
       .connect("par",  par.template output<"key">(),   "keys", keys.template input<"key">())
       .connect("par",  par.template output<"value">(), "vals", vals.template input<"value">())
       .build();

    net.start();
    std::this_thread::sleep_for(std::chrono::milliseconds(600));
    net.stop();
}