package launch

import (
	"encoding/json"
	"errors"
	"os"
	"path/filepath"
	"sync"
	"testing"
	"time"
)

// A bundle that answers `mesh/event` as $ANSWER says: an error, a result, or an answer with neither.
const answeringBundle = `#!/bin/sh
while IFS= read -r line; do
  id=$(printf '%s' "$line" | sed -n 's/.*"id":\([0-9]*\)[,}].*/\1/p')
  case "$line" in
    *'"method":"initialize"'*) printf '{"jsonrpc":"2.0","id":%s,"result":{}}\n' "$id" ;;
    *'"method":"tools/list"'*)
      printf '{"jsonrpc":"2.0","id":%s,"result":{"tools":[]}}\n' "$id"
      printf '{"jsonrpc":"2.0","id":"s1","method":"mesh/subscribe","params":{"pattern":"#"}}\n' ;;
    *'"method":"mesh/event"'*)
      case "$ANSWER" in
        error) printf '{"jsonrpc":"2.0","id":%s,"error":{"code":-32000,"message":"Unexpected end of JSON input"}}\n' "$id" ;;
        result) printf '{"jsonrpc":"2.0","id":%s,"result":{}}\n' "$id" ;;
        bare) printf '{"jsonrpc":"2.0","id":%s}\n' "$id" ;;
      esac ;;
  esac
done
`

type subscribing struct {
	mu      sync.Mutex
	deliver func(json.RawMessage) error
}

func (b *subscribing) Publish(json.RawMessage) error                          { return nil }
func (b *subscribing) Ask(json.RawMessage) (json.RawMessage, error)           { return nil, nil }
func (b *subscribing) State(string, json.RawMessage) (json.RawMessage, error) { return nil, nil }
func (b *subscribing) Watch(json.RawMessage, func(json.RawMessage) error) (func(), error) {
	return func() {}, nil
}
func (b *subscribing) Subscribe(d func(json.RawMessage) error) error {
	b.mu.Lock()
	defer b.mu.Unlock()
	b.deliver = d
	return nil
}

func deliverTo(t *testing.T, answer string) error {
	t.Helper()
	entry := filepath.Join(t.TempDir(), "bundle")
	if err := os.WriteFile(entry, []byte(answeringBundle), 0o755); err != nil {
		t.Fatal(err)
	}
	b := &subscribing{}
	l, err := Start("plex", entry, append(os.Environ(), "ANSWER="+answer), b, t.Logf)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(l.Stop)
	for i := 0; ; i++ {
		b.mu.Lock()
		d := b.deliver
		b.mu.Unlock()
		if d != nil {
			return d(json.RawMessage(`{"key":"radarr.download.completed","body":{"title":"x"}}`))
		}
		if i > 100 {
			t.Fatal("the bundle never subscribed")
		}
		time.Sleep(20 * time.Millisecond)
	}
}

// An event is taken by any answer that is not an error, and not taken by an error, which reaches the
// runtime as the bundle's own words — not as something the runtime failed to read (hq issue 276).
func TestAnEventIsTakenByAnyAnswerThatIsNotAnError(t *testing.T) {
	for _, answer := range []string{"result", "bare"} {
		if err := deliverTo(t, answer); err != nil {
			t.Errorf("an answer %q did not take the event: %v", answer, err)
		}
	}
	err := deliverTo(t, "error")
	var refused *Refused
	if !errors.As(err, &refused) || refused.Method != "mesh/event" || refused.Message != "Unexpected end of JSON input" {
		t.Fatalf("an error answer was not the bundle's refusal of mesh/event: %#v", err)
	}
}