package journslog

import (
	"log/slog"
	"net/http"
	"path/filepath"
	"strings"
	"testing"
	"testing/slogtest"
	"time"
	"uuid"

	"src.lwithers.me.uk/go/journal"
	"src.lwithers.me.uk/go/journal/testsink"
)

// TestHandler emits a log message with various attributes / groups and ensures
// the result is logged successfully.
func TestHandler(t *testing.T) {
	sockpath := filepath.Join(t.TempDir(), "socket")
	sink, err := testsink.New(sockpath)
	if err != nil {
		t.Fatal(err)
	}
	defer sink.Stop()

	conn, err := journal.Connect(sockpath)
	if err != nil {
		t.Fatal(err)
	}
	defer conn.Close()

	jh, err := NewHandler(WithConn(conn))
	if err != nil {
		t.Fatal(err)
	}

	httpGroup := slog.Group("http", "path", "/foo", "status", http.StatusOK)
	logger := slog.New(jh)
	logger = logger.With("global_attr_key", "global_attr_val", httpGroup).WithGroup("app")
	logger.Info("hello, journal", "slowkey", slowValue("slowval"), slog.Group("g1", "attr1", "val1", "attr2", 123))

	msg, err := sink.Message(0)
	if err != nil {
		t.Fatal(err)
	}

	msgText, attrs, err := msg.Decode()
	if err != nil {
		t.Error(err)
	}
	if msgText != "hello, journal" {
		t.Errorf("unexpected message text %q", msgText)
	}

	expAttrs := []testsink.DecodedAttr{
		testsink.DecodedAttr{Key: "PRIORITY", Val: "6"},
		testsink.DecodedAttr{Key: "GLOBAL_ATTR_KEY", Val: "global_attr_val"},
		testsink.DecodedAttr{Key: "HTTP_PATH", Val: "/foo"},
		testsink.DecodedAttr{Key: "HTTP_STATUS", Val: "200"},
		testsink.DecodedAttr{Key: "APP_SLOWKEY", Val: "slowval"},
		testsink.DecodedAttr{Key: "APP_G1_ATTR1", Val: "val1"},
		testsink.DecodedAttr{Key: "APP_G1_ATTR2", Val: "123"},
	}

	for i := range expAttrs {
		key := expAttrs[i].Key
		val, ok := testsink.GetAttr(attrs, key)
		switch {
		case !ok:
			t.Errorf("missing %s attribute", key)
		case val != expAttrs[i].Val:
			t.Errorf("unexpected %s value", key)
		}
	}

	if t.Failed() {
		for i := range attrs {
			t.Errorf("attr %q=%q", attrs[i].Key, attrs[i].Val)
		}
	}
}

type slowValue string

func (s slowValue) LogValue() slog.Value {
	return slog.StringValue(string(s))
}

// TestSlog integrates with [testing/slogtest].
func TestSlog(t *testing.T) {
	tmpdir := t.TempDir()

	attrsFromTime := func(t time.Time) []slog.Attr {
		return []slog.Attr{
			{
				Key:   "TEST_TIME",
				Value: slog.StringValue(t.Format(time.RFC3339Nano)),
			},
		}
	}

	attrsFromLevel := func(l slog.Level) []slog.Attr {
		return []slog.Attr{
			{
				Key:   "TEST_LEVEL",
				Value: slog.StringValue(l.String()),
			},
		}
	}

	// XXX: this relies on [slogtest.Run] executing its test cases
	// completely sequentially
	var curSink *testsink.Sink

	newHandler := func(t *testing.T) slog.Handler {
		sockpath := filepath.Join(tmpdir, uuid.New().String())
		sink, err := testsink.New(sockpath)
		if err != nil {
			t.Fatalf("failed to create test sink: %v", err)
		}

		conn, err := journal.Connect(sockpath)
		if err != nil {
			sink.Stop()
			t.Fatalf("failed to connect to test sink socket: %v", err)
		}

		h, err := NewHandler(WithConn(conn), WithAttrsFromTime(attrsFromTime), WithAttrsFromLevel(attrsFromLevel), WithHandlerOptions(slog.HandlerOptions{
			Level: slog.LevelInfo,
		}))
		if err != nil {
			sink.Stop()
			t.Fatalf("failed to create handler: %v", err)
		}

		curSink = sink
		return h
	}

	result := func(t *testing.T) map[string]any {
		defer curSink.Stop()

		m, err := curSink.Message(0)
		if err != nil {
			t.Fatalf("failed to fetch message from test sink: %v", err)
		}

		msg, attrs, err := m.Decode()
		if err != nil {
			t.Errorf("failed to decode message from test sink: %v", err)
		}

		out := make(map[string]any)
		out[slog.MessageKey] = msg
		for i := range attrs {
			k, v := attrs[i].Key, attrs[i].Val
			switch k {
			case "TEST_TIME":
				out[slog.TimeKey] = v
			case "TEST_LEVEL":
				out[slog.LevelKey] = v
			default:
				parts := strings.Split(k, "_")
				Ng := len(parts) - 1 // number of groups
				g := out
				for i := range Ng {
					next, _ := g[parts[i]].(map[string]any)
					if next == nil {
						next = make(map[string]any)
						g[parts[i]] = next
					}
					g = next
				}
				g[strings.ToLower(parts[Ng])] = v
			}
		}
		return out
	}

	slogtest.Run(t, newHandler, result)
}