// Demonstrates request ID propagation between server and client.
// The server assigns a request ID to incoming requests, and the client
// middleware forwards it to downstream services via X-Request-Id header.
package main

import (
	"fmt"
	"log"
	"log/slog"
	"net/http"

	"git.codelab.vc/pkg/httpx"
	"git.codelab.vc/pkg/httpx/middleware"
	"git.codelab.vc/pkg/httpx/server"
)

func main() {
	logger := slog.Default()

	// Client that propagates request IDs from context.
	client := httpx.New(
		httpx.WithBaseURL("http://localhost:9090"),
		httpx.WithMiddleware(
			middleware.RequestID(), // Picks up ID from context, sets X-Request-Id.
		),
	)
	defer client.Close()

	r := server.NewRouter()

	r.HandleFunc("GET /proxy", func(w http.ResponseWriter, r *http.Request) {
		// The request ID is in r.Context() thanks to server.RequestID().
		id := server.RequestIDFromContext(r.Context())
		logger.Info("handling request", "request_id", id)

		// Client automatically forwards the request ID to downstream.
		resp, err := client.Get(r.Context(), "/downstream")
		if err != nil {
			server.WriteError(w, http.StatusBadGateway, fmt.Sprintf("downstream error: %v", err))
			return
		}
		defer resp.Close()

		body, _ := resp.String()
		server.WriteJSON(w, http.StatusOK, map[string]string{
			"request_id":          id,
			"downstream_response": body,
		})
	})

	// Server with RequestID middleware that assigns IDs to incoming requests.
	srv := server.New(r, server.Defaults(logger)...)
	log.Fatal(srv.ListenAndServe())
}