package dispatch

import (
	"context"
	"sync/atomic"
	"testing"
	"time"

	"github.com/gochat/gochat/internal/channel"
	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/worker"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

type dispatchWorkerListener struct {
	name  string
	count atomic.Int32
}

func (l *dispatchWorkerListener) Name() string { return l.name }

func (l *dispatchWorkerListener) OnEvent(ctx context.Context, event *channel.ChannelEvent) error {
	l.count.Add(1)
	return nil
}

func newDispatchWorkerDB(t *testing.T) *gorm.DB {
	t.Helper()
	db, err := gorm.Open(sqlite.Open("file:dispatch-worker?mode=memory&cache=shared"), &gorm.Config{Logger: logger.Default.LogMode(logger.Silent)})
	if err != nil {
		t.Fatalf("open sqlite: %v", err)
	}
	sqlDB, err := db.DB()
	if err != nil {
		t.Fatalf("sqlite db handle: %v", err)
	}
	sqlDB.SetMaxOpenConns(1)
	if err := db.AutoMigrate(&model.BackgroundJob{}); err != nil {
		t.Fatalf("migrate background jobs: %v", err)
	}
	t.Cleanup(func() {
		db.Exec("DELETE FROM background_jobs")
		sqlDB.Close()
	})
	return db
}

func TestEventDispatcherQueuesAsyncListenersDurably(t *testing.T) {
	db := newDispatchWorkerDB(t)
	wp := worker.NewWorkerPoolWithOptions(db, worker.WithNow(func() time.Time { return time.Date(2026, 6, 5, 11, 30, 0, 0, time.UTC) }))
	ed := NewEventDispatcher(channel.NewDispatcher())
	ed.SetWorkerPool(wp)
	syncListener := &dispatchWorkerListener{name: "sync-listener"}
	asyncListener := &dispatchWorkerListener{name: "async-listener"}
	ed.RegisterSync(syncListener, string(channel.EventConversationCreated))
	ed.RegisterAsync(asyncListener, string(channel.EventConversationCreated))

	event := channel.NewChannelEvent(channel.EventConversationCreated, channel.ChannelWebWidget, 1, 2)
	if err := ed.Dispatch(context.Background(), event); err != nil {
		t.Fatalf("dispatch: %v", err)
	}
	if syncListener.count.Load() != 1 {
		t.Fatalf("sync listener should run immediately")
	}
	if asyncListener.count.Load() != 0 {
		t.Fatalf("async listener should wait for durable worker")
	}

	var count int64
	if err := db.Model(&model.BackgroundJob{}).Where("job_type = ? AND status = ?", TaskTypeEventListenerDispatch, model.BackgroundJobStatusQueued).Count(&count).Error; err != nil {
		t.Fatalf("count jobs: %v", err)
	}
	if count != 1 {
		t.Fatalf("expected one queued listener dispatch job, got %d", count)
	}
	processed, err := wp.ProcessOne(context.Background())
	if err != nil || !processed {
		t.Fatalf("process listener job: processed=%v err=%v", processed, err)
	}
	if asyncListener.count.Load() != 1 {
		t.Fatalf("async listener was not called by worker")
	}
}

func TestEventDispatcherDispatchAsyncQueuesAllMatchingListeners(t *testing.T) {
	db := newDispatchWorkerDB(t)
	wp := worker.NewWorkerPoolWithOptions(db, worker.WithNow(func() time.Time { return time.Date(2026, 6, 5, 11, 45, 0, 0, time.UTC) }))
	ed := NewEventDispatcher(channel.NewDispatcher())
	ed.SetWorkerPool(wp)
	one := &dispatchWorkerListener{name: "one"}
	two := &dispatchWorkerListener{name: "two"}
	ed.RegisterSync(one, string(channel.EventMessageCreated))
	ed.RegisterAsync(two, string(channel.EventMessageCreated))

	ed.DispatchAsync(context.Background(), channel.NewChannelEvent(channel.EventMessageCreated, channel.ChannelAPI, 1, 2))
	for i := 0; i < 2; i++ {
		processed, err := wp.ProcessOne(context.Background())
		if err != nil || !processed {
			t.Fatalf("process listener job %d: processed=%v err=%v", i, processed, err)
		}
	}
	if one.count.Load() != 1 || two.count.Load() != 1 {
		t.Fatalf("expected both listeners via durable jobs, got one=%d two=%d", one.count.Load(), two.count.Load())
	}
}