// resources 演示队列暂停、积压背压、幂等核对、释放空间与限速执行。
package main

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"time"

	orbit "git.yuntuo.hk/k2safe/orbit/sdk/go"
)

func main() {
	if err := run(); err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}
func run() error {
	token := os.Getenv("ORBIT_TOKEN")
	if path := os.Getenv("ORBIT_CREDENTIALS_FILE"); path != "" && token == "" {
		raw, err := os.ReadFile(path)
		if err != nil {
			return err
		}
		var c struct {
			Token string `json:"token"`
		}
		if err := json.Unmarshal(raw, &c); err != nil {
			return err
		}
		token = c.Token
	}
	api, err := orbit.NewClient(os.Getenv("ORBIT_URL"), orbit.Options{Token: token})
	if err != nil {
		return err
	}
	ctx, cancel := context.WithTimeout(context.Background(), 25*time.Second)
	defer cancel()
	op, err := orbit.NewWorkerMessageID()
	if err != nil {
		return err
	}
	name := "resources." + op
	created, err := api.CreateQueue(ctx, "queue-"+op, orbit.CreateQueueRequest{Name: name, MaxConcurrency: 2, RatePerSecond: 1, MaxUnfinishedTasks: 2})
	if err != nil {
		return err
	}
	q := created.Queue
	configure := func(paused bool) error {
		out, err := api.ConfigureQueue(ctx, q.ID, fmt.Sprintf("configure-%s-%t", op, paused), orbit.ConfigureQueueRequest{ExpectedRevision: q.Revision, Reason: "resource control example", Paused: paused, MaxConcurrency: 2, RatePerSecond: 1, MaxUnfinishedTasks: 2})
		if err == nil {
			q = out.Queue
		}
		return err
	}
	if err := configure(true); err != nil {
		return err
	}
	in := orbit.SubmitTaskRequest{QueueID: q.ID, Handler: name, HandlerVersion: "v1", PayloadVersion: "v1", Payload: json.RawMessage(`{"object_ref":"objects/example","n":9007199254740993}`), TaskTimeoutMS: 20000, Retry: orbit.RetryPolicy{MaxAttempts: 1, AttemptTimeoutMS: 10000}}
	first, err := api.SubmitTask(ctx, "first-"+op, in)
	if err != nil {
		return err
	}
	second, err := api.SubmitTask(ctx, "second-"+op, in)
	if err != nil {
		return err
	}
	_, err = api.SubmitTask(ctx, "third-"+op, in)
	var rejected *orbit.APIError
	if !errors.As(err, &rejected) || rejected.Code != "QUEUE_FULL" {
		return fmt.Errorf("expected QUEUE_FULL, got %v", err)
	}
	fmt.Printf("backpressure=%s http=%d\n", rejected.Code, rejected.StatusCode)
	duplicate, err := api.SubmitTask(ctx, "first-"+op, in)
	if err != nil {
		return err
	}
	if !duplicate.Deduplicated || duplicate.Task.ID != first.Task.ID {
		return errors.New("original receipt was not preserved")
	}
	if _, err := api.CancelTask(ctx, first.Task.ID, "cancel-"+op, orbit.CancelTaskRequest{ExpectedRevision: first.Task.Revision, Reason: "free one unfinished slot"}); err != nil {
		return err
	}
	// 明确 429 表示未受理；释放空间后仍使用第三个任务的原幂等键与原内容。
	third, err := api.SubmitTask(ctx, "third-"+op, in)
	if err != nil {
		return err
	}
	fmt.Println("duplicate=true rejected_request_retried=true")
	w, err := orbit.NewWorker(api, orbit.WorkerOptions{QueueID: q.ID, Capacity: 2, ShutdownTimeout: 5 * time.Second, Handlers: []orbit.WorkerHandler{{Capability: orbit.WorkerCapability{Handler: name, HandlerVersion: "v1", PayloadVersion: "v1"}, Handle: func(ctx context.Context, e orbit.WorkerExecution) (json.RawMessage, error) {
		if err := ctx.Err(); err != nil {
			return nil, err
		}
		return e.Task.Payload, nil
	}}}})
	if err != nil {
		return err
	}
	run, stop := context.WithCancel(ctx)
	done := make(chan error, 1)
	go func() { done <- w.Run(run) }()
	waited := false
	defer func() {
		stop()
		if !waited {
			<-done
		}
	}()
	if err := configure(false); err != nil {
		return err
	}
	for _, id := range []string{second.Task.ID, third.Task.ID} {
		for {
			task, err := api.GetTask(ctx, id)
			if err != nil {
				return err
			}
			if task.State == orbit.TaskSucceeded {
				fmt.Printf("task=%s state=%s attempts=%d\n", id, task.State, task.AttemptCount)
				break
			}
			if task.State == orbit.TaskFailed || task.State == orbit.TaskNeedsReview || task.State == orbit.TaskCancelled {
				return fmt.Errorf("unexpected task state: %s", task.State)
			}
			select {
			case <-ctx.Done():
				return ctx.Err()
			case <-time.After(80 * time.Millisecond):
			}
		}
	}
	q, err = api.GetQueue(ctx, q.ID)
	if err != nil {
		return err
	}
	if q.UnfinishedTasks != 0 {
		return errors.New("queue still has unfinished work")
	}
	stop()
	err = <-done
	waited = true
	if err != nil {
		return err
	}
	fmt.Printf("unfinished=%d rate_per_second=%d worker_drained=true\n", q.UnfinishedTasks, q.RatePerSecond)
	return nil
}