// modules combines caching, outbound calls, middleware and background jobs.
package main

import (
	"context"
	"encoding/json"
	"errors"
	"flag"
	"log"
	"os"
	"os/signal"
	"sync/atomic"
	"syscall"
	"time"

	omni "git.yuntuo.hk/k2safe/go-omni"
	"git.yuntuo.hk/k2safe/go-omni/auth"
	"git.yuntuo.hk/k2safe/go-omni/cache"
	"git.yuntuo.hk/k2safe/go-omni/httpc"
	"git.yuntuo.hk/k2safe/go-omni/logx"
	"git.yuntuo.hk/k2safe/go-omni/middleware"
	"git.yuntuo.hk/k2safe/go-omni/task"
)

func newApp(settings omni.Config, token, upstream string) (application *omni.App, err error) {
	application = omni.New(omni.WithConfig(settings))
	defer func(app *omni.App) {
		if err != nil {
			_ = app.Close()
		}
	}(application)
	store, err := cache.NewMemory(cache.MemoryConfig{MaxEntries: 128, MaxBytes: 1 << 20})
	if err != nil {
		return nil, err
	}
	application.OnShutdown(store.Close)
	loader, err := cache.NewLoader(store, cache.LoaderConfig{MaxLoads: 8, Timeout: time.Second})
	if err != nil {
		return application, err
	}
	client, err := httpc.New(httpc.Config{Timeout: time.Second, MaxRetries: 1, MaxConnsPerHost: 8})
	if err != nil {
		return application, err
	}
	application.OnShutdown(client.Close)
	jobs, err := task.New(task.Config{Workers: 2, QueueSize: 16, TaskTimeout: 2 * time.Second})
	if err != nil {
		return application, err
	}
	// Reverse cleanup order: drain jobs before closing their dependencies.
	application.OnShutdown(jobs.Close)
	if err = jobs.Every("reportStats", time.Minute, func(ctx context.Context) error {
		logx.InfoContext(ctx, "jobs.stats", "stats", jobs.Stats())
		return nil
	}); err != nil {
		return application, err
	}
	limiter, err := middleware.NewRateLimiter(middleware.RateLimitConfig{Rate: 20, Burst: 40, MaxKeys: 128, Key: func(c *omni.Context) string { p, _ := auth.FromContext(c); return p.UserID }})
	if err != nil {
		return application, err
	}
	idempotency, err := middleware.NewIdempotency(middleware.IdempotencyConfig{Scope: func(c *omni.Context) (string, error) { p, _ := auth.FromContext(c); return p.UserID, nil }})
	if err != nil {
		return application, err
	}
	api := application.Group("/api", middleware.Timeout(2*time.Second), auth.RequireAuth(auth.StaticAuthenticator{token: {UserID: "demo-user"}}), limiter.Middleware())
	api.GET("/catalog", func(c *omni.Context) error {
		value, err := loader.GetOrLoad(c.Context(), "publicCatalog:v1", 30*time.Second, func(ctx context.Context) ([]byte, error) {
			data := map[string]any{"name": "demo catalog"}
			if upstream != "" {
				if err := client.JSON(ctx, "GET", upstream, nil, &data); err != nil {
					return nil, err
				}
			}
			return json.Marshal(data)
		})
		if err != nil {
			return err
		}
		return c.OK(json.RawMessage(value))
	})
	var nextID atomic.Uint64
	api.POST("/jobs", func(c *omni.Context) error {
		var input struct {
			Name string `json:"name" binding:"required,max=100"`
		}
		if err := c.BindJSON(&input); err != nil {
			return err
		}
		id := nextID.Add(1)
		// This job deliberately outlives the HTTP request. Runner still applies
		// its own deadline and shutdown cancellation; log correlation survives.
		_, err := jobs.Submit(context.WithoutCancel(c.Context()), "demoJob", func(ctx context.Context) error {
			logx.InfoContext(ctx, "job.finished", "jobId", id, "name", input.Name)
			return nil
		})
		if errors.Is(err, task.ErrQueueFull) {
			return omni.NewError(503, "QUEUE_FULL", "job queue is full")
		}
		if err != nil {
			return err
		}
		return c.Accepted(map[string]uint64{"jobId": id})
	}, idempotency.Middleware())
	api.GET("/jobs", func(c *omni.Context) error { return c.OK(jobs.Stats()) })
	return application, nil
}

func run(ctx context.Context) error {
	settings, err := omni.LoadConfig(*configPath)
	if err != nil {
		return err
	}

	token := os.Getenv("GO_OMNI_DEV_TOKEN")
	if token == "" {
		token = "dev-token"
	}
	application, err := newApp(settings, token, os.Getenv("GO_OMNI_DEMO_UPSTREAM"))
	if err != nil {
		return err
	}
	return application.RunContext(ctx)
}

var configPath = flag.String("config", "examples/modules/config.yaml", "configuration file")

func main() {
	flag.Parse()
	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()
	if err := run(ctx); err != nil {
		log.Fatal(err)
	}
}