// Command server is a browser chat over claude_wire — the network-intercept path.
// For each message it launches claude_wire, which drives the interactive claude TUI
// through a mitmproxy and reads the model's SSE off the wire, then relays the
// resulting NDJSON (text_delta + result) to the browser as Server-Sent Events.
//
// Versus the claude_pipe chat (which parses the terminal render), this one shows the
// exact model text token by token and finishes as soon as the model's message_stop
// arrives — no blind idle wait. ~9s vs ~15s per message.
//
// claude_wire uses a fixed mitmproxy port, so messages are serialized with a mutex
// (a chat is sequential anyway: you wait for the reply before sending the next).
//
// Each message is an independent one-shot claude session (no memory across turns).
//
// Run:
//
//	cd apps/claude_pipe && CGO_ENABLED=1 go build -tags fts5 -o claude_pipe .   # the TUI driver
//	cd ../claude_wire   && go build -o claude_wire .                            # the runner
//	cd playground       && go run ./web                                        # http://localhost:8100
package main

import (
	"bufio"
	_ "embed"
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"sync"
)

//go:embed index.html
var indexHTML []byte

var (
	wireBin string
	root    string
	one     sync.Mutex // serialize: one claude_wire at a time (fixed proxy port)
)

func main() {
	port := flag.String("port", "8100", "port to listen on")
	bin := flag.String("wire", "/home/enmanuel/fn_registry/apps/claude_wire/claude_wire", "path to the claude_wire binary")
	rootDir := flag.String("root", "/home/enmanuel/fn_registry", "cwd for claude (MCP-approved repo)")
	flag.Parse()

	abs, err := filepath.Abs(*bin)
	if err != nil {
		log.Fatalf("resolve --wire: %v", err)
	}
	if _, err := os.Stat(abs); err != nil {
		log.Fatalf("claude_wire binary not found at %s — build it first:\n  (cd .. && go build -o claude_wire .)", abs)
	}
	wireBin, root = abs, *rootDir

	http.HandleFunc("/", handleIndex)
	http.HandleFunc("/chat", handleChat)

	log.Printf("claude_wire web chat → http://localhost:%s  (wire=%s root=%s)", *port, wireBin, root)
	log.Fatal(http.ListenAndServe(":"+*port, nil))
}

func handleIndex(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/" {
		http.NotFound(w, r)
		return
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	_, _ = w.Write(indexHTML)
}

// handleChat runs claude_wire for the prompt and relays its NDJSON as SSE.
func handleChat(w http.ResponseWriter, r *http.Request) {
	prompt := r.URL.Query().Get("prompt")
	if prompt == "" {
		http.Error(w, "missing prompt", http.StatusBadRequest)
		return
	}
	flusher, ok := w.(http.Flusher)
	if !ok {
		http.Error(w, "streaming unsupported", http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", "text/event-stream")
	w.Header().Set("Cache-Control", "no-cache")
	w.Header().Set("Connection", "keep-alive")
	w.Header().Set("X-Accel-Buffering", "no")

	// Serialize: claude_wire binds a fixed mitmproxy port.
	one.Lock()
	defer one.Unlock()

	cmd := exec.CommandContext(r.Context(), wireBin, "--prompt", prompt, "--cwd", root)
	stdout, err := cmd.StdoutPipe()
	if err != nil {
		sse(w, flusher, "error", fmt.Sprintf(`{"message":%q}`, err.Error()))
		return
	}
	cmd.Stderr = os.Stderr
	if err := cmd.Start(); err != nil {
		sse(w, flusher, "error", fmt.Sprintf(`{"message":%q}`, err.Error()))
		return
	}

	sc := bufio.NewScanner(stdout)
	sc.Buffer(make([]byte, 1024*1024), 1024*1024)
	for sc.Scan() {
		sse(w, flusher, "", sc.Text())
	}
	_ = cmd.Wait()
	sse(w, flusher, "done", "{}")
}

func sse(w http.ResponseWriter, f http.Flusher, event, data string) {
	if event != "" {
		fmt.Fprintf(w, "event: %s\n", event)
	}
	fmt.Fprintf(w, "data: %s\n\n", data)
	f.Flush()
}