package conga_test

import (
	"context"
	"fmt"
	"testing"
	"time"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/conga"
	"git.golem15.com/golem15/summercms/modules/pact"
	"git.golem15.com/golem15/summercms/modules/party"
	"gorm.io/gorm"
)

// ImportPostsArgs are the arguments of the acme.blog post import job.
type ImportPostsArgs struct {
	File string `json:"file"`
}

// Kind names the job. It must be unique across the application.
func (ImportPostsArgs) Kind() string { return "acme_blog_import_posts" }

func ExampleJob() {
	job := conga.Job(func(ctx context.Context, args ImportPostsArgs) error {
		_, dispatched := conga.JobID(ctx)
		fmt.Println("import", args.File, "with a summer_jobs row:", dispatched)
		return nil
	}, conga.OnQueue("imports"), conga.MaxAttempts(5), conga.Timeout(10*time.Minute))

	// A worker calls Work with the decoded arguments; a unit test can too.
	if err := job.Work(context.Background(), ImportPostsArgs{File: "posts.csv"}); err != nil {
		fmt.Println(err)
	}
	fmt.Println(ImportPostsArgs{}.Kind())
	// Output:
	// import posts.csv with a summer_jobs row: false
	// acme_blog_import_posts
}

// ImportPostsJob is the acme.blog import job. It reports progress on its
// summer_jobs row, stops when the row is cancelled and completes the row.
func ImportPostsJob(m *conga.Manager) pact.Job {
	return conga.Job(func(ctx context.Context, args ImportPostsArgs) error {
		id, _ := conga.JobID(ctx)
		rows := []string{args.File} // ... read the rows of args.File ...
		if err := m.StartJob(ctx, id, len(rows)); err != nil {
			return err
		}
		for i := range rows {
			canceled, err := m.CheckIfCanceled(ctx, id)
			if err != nil {
				return err
			}
			if canceled {
				return m.StopJob(ctx, id, nil)
			}
			// ... import rows[i] ...
			if err := m.UpdateJobState(ctx, id, i+1, nil); err != nil {
				return err
			}
		}
		return m.CompleteJob(ctx, id, map[string]any{"imported": len(rows)})
	}, conga.OnQueue("imports"))
}

// BlogPlugin is the acme.blog plugin; only its jobs are shown here.
type BlogPlugin struct {
	jobs *conga.Manager
}

var _ pact.HasJobs = (*BlogPlugin)(nil)

func (p *BlogPlugin) ID() string         { return "acme.blog" }
func (p *BlogPlugin) Requires() []string { return nil }

// Register keeps the application's job manager for the plugin's jobs.
func (p *BlogPlugin) Register(app *backpack.App) error {
	m, err := conga.From(app)
	p.jobs = m
	return err
}

func (p *BlogPlugin) Boot(app *backpack.App) error { return nil }

// Jobs returns the plugin's background jobs; every worker registers them.
func (p *BlogPlugin) Jobs() []pact.Job {
	return []pact.Job{ImportPostsJob(p.jobs)}
}

// startImport dispatches the import job in the transaction of the write
// that needs it and returns the summer_jobs row id.
func startImport(ctx context.Context, app *backpack.App, db *gorm.DB, file string) (uint, error) {
	// docs:start dispatch
	m, err := conga.From(app)
	if err != nil {
		return 0, err
	}
	var id uint
	err = db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		// ... write the import's own records on tx ...
		id, err = m.Dispatch(ctx, tx, ImportPostsArgs{File: file}, conga.DispatchOpts{
			Label: "Import posts",
			Count: 1,
		})
		return err
	})
	return id, err
	// docs:end dispatch
}

// importStatus reads the progress of a dispatched job from its row.
func importStatus(ctx context.Context, m *conga.Manager, id uint) (string, error) {
	// docs:start status
	rec, err := m.Get(ctx, id)
	if err != nil {
		return "", err
	}
	switch rec.Status {
	case conga.StatusComplete:
		return fmt.Sprintf("%s: done (%d/%d)", rec.Label, rec.Progress, rec.ProgressMax), nil
	case conga.StatusError, conga.StatusStopped:
		return fmt.Sprintf("%s: failed or stopped", rec.Label), nil
	default:
		return fmt.Sprintf("%s: %d/%d", rec.Label, rec.Progress, rec.ProgressMax), nil
	}
	// docs:end status
}

// TestDocsDispatch runs the dispatch region of the Jobs page on the
// package's Postgres harness: a worker registers the plugin's job, the job
// is dispatched in a transaction and completes its row.
func TestDocsDispatch(t *testing.T) {
	app, db := conga.DocsApp(t)
	plugin := &BlogPlugin{}
	if err := plugin.Register(app); err != nil {
		t.Fatal(err)
	}
	if n := len(plugin.Jobs()); n != 1 {
		t.Fatalf("Jobs() = %d jobs, want 1", n)
	}
	w, err := conga.StartWorker(t.Context(), app, []party.Plugin{plugin}, conga.WorkerOptions{})
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() {
		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()
		if err := w.Stop(ctx); err != nil {
			t.Errorf("stop worker: %v", err)
		}
	})

	id, err := startImport(t.Context(), app, db, "posts.csv")
	if err != nil {
		t.Fatal(err)
	}
	m, err := conga.From(app)
	if err != nil {
		t.Fatal(err)
	}
	deadline := time.Now().Add(15 * time.Second)
	for {
		got, err := importStatus(t.Context(), m, id)
		if err != nil {
			t.Fatal(err)
		}
		if got == "Import posts: done (1/1)" {
			return
		}
		if time.Now().After(deadline) {
			t.Fatalf("status = %q, want the job to complete", got)
		}
		time.Sleep(25 * time.Millisecond)
	}
}