package opencode

import (
	"context"
	"fmt"
	"net"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"banger/internal/vsockagent"
)

func TestServiceUnitContainsExpectedExecStart(t *testing.T) {
	unit := ServiceUnit()
	for _, snippet := range []string{
		"RequiresMountsFor=/root",
		"WorkingDirectory=/root",
		"Environment=HOME=/root",
		"ExecStart=/usr/local/bin/opencode serve --hostname 0.0.0.0 --port 4096",
		"WantedBy=multi-user.target",
	} {
		if !strings.Contains(unit, snippet) {
			t.Fatalf("service unit missing snippet %q\nunit:\n%s", snippet, unit)
		}
	}
}

func TestRunitRunScriptContainsExpectedExec(t *testing.T) {
	script := RunitRunScript()
	for _, snippet := range []string{
		"export HOME=/root",
		"cd /root",
		"exec /usr/local/bin/opencode serve --hostname 0.0.0.0 --port 4096",
	} {
		if !strings.Contains(script, snippet) {
			t.Fatalf("runit script missing snippet %q\nscript:\n%s", snippet, script)
		}
	}
}

func TestReadyMatchesTCPPort(t *testing.T) {
	if Ready([]vsockagent.PortListener{{Proto: "udp", Port: Port}}) {
		t.Fatal("udp listener should not satisfy readiness")
	}
	if Ready([]vsockagent.PortListener{{Proto: "tcp", Port: 8080}}) {
		t.Fatal("wrong tcp port should not satisfy readiness")
	}
	if !Ready([]vsockagent.PortListener{{Proto: "tcp", Port: Port}}) {
		t.Fatal("tcp listener on opencode port should satisfy readiness")
	}
}

func TestWaitReadyReturnsWhenPortIsListening(t *testing.T) {
	socketPath := filepath.Join(t.TempDir(), "opencode.vsock")
	listener, err := net.Listen("unix", socketPath)
	if err != nil {
		t.Fatalf("listen: %v", err)
	}
	t.Cleanup(func() {
		_ = listener.Close()
		_ = os.Remove(socketPath)
	})

	serverDone := make(chan error, 1)
	go func() {
		conn, err := listener.Accept()
		if err != nil {
			serverDone <- err
			return
		}
		defer conn.Close()
		buf := make([]byte, 512)
		n, err := conn.Read(buf)
		if err != nil {
			serverDone <- err
			return
		}
		if got := string(buf[:n]); got != "CONNECT 42070\n" {
			serverDone <- fmt.Errorf("unexpected connect message %q", got)
			return
		}
		if _, err := conn.Write([]byte("OK 1\n")); err != nil {
			serverDone <- err
			return
		}
		reqBuf := make([]byte, 0, 512)
		for {
			n, err = conn.Read(buf)
			if err != nil {
				serverDone <- err
				return
			}
			reqBuf = append(reqBuf, buf[:n]...)
			if strings.Contains(string(reqBuf), "\r\n\r\n") {
				break
			}
		}
		if !strings.Contains(string(reqBuf), "GET /ports HTTP/1.1\r\n") {
			serverDone <- fmt.Errorf("unexpected ports payload %q", string(reqBuf))
			return
		}
		body := []byte(`{"listeners":[{"proto":"tcp","bind_address":"0.0.0.0","port":4096}]}`)
		_, err = conn.Write([]byte(fmt.Sprintf("HTTP/1.1 200 OK\r\nContent-Type: application/json\r\nContent-Length: %d\r\n\r\n%s", len(body), body)))
		serverDone <- err
	}()

	if err := waitReady(context.Background(), nil, socketPath, time.Second, nil); err != nil {
		t.Fatalf("waitReady: %v", err)
	}
	if err := <-serverDone; err != nil {
		t.Fatalf("server: %v", err)
	}
}