package conga

import (
	"bytes"
	"context"
	"fmt"
	"reflect"
	"strings"
	"sync/atomic"
	"testing"
	"time"

	"git.golem15.com/golem15/summercms/modules/bonfire"
)

// TestQueueClear covers D-05 and CLI-06: available, scheduled and
// retryable jobs of one queue are deleted in batches until a pass deletes
// none; a running job and other queues are left alone.
func TestQueueClear(t *testing.T) {
	db, dsn := migratedDB(t)
	app, gdb := testApp(t, db, dsn, map[string]any{"queue.queues.default": 1})
	m, err := From(app)
	if err != nil {
		t.Fatal(err)
	}
	release := make(chan struct{})
	started := make(chan struct{}, 1)
	var pings atomic.Int32
	block := Job(func(ctx context.Context, a blockArgs) error {
		started <- struct{}{}
		select {
		case <-release:
			return nil
		case <-ctx.Done():
			return ctx.Err()
		}
	})
	ping := Job(func(ctx context.Context, a pingArgs) error {
		pings.Add(1)
		return nil
	})
	startTestWorker(t, app, WorkerOptions{}, block, ping)
	ctx := t.Context()
	if err := m.Enqueue(ctx, nil, blockArgs{}, EnqueueOpts{}); err != nil {
		t.Fatal(err)
	}
	select {
	case <-started:
	case <-time.After(5 * time.Second):
		t.Fatal("blocking job did not start")
	}
	for range 2 {
		if err := m.Enqueue(ctx, nil, pingArgs{Tag: "pending"}, EnqueueOpts{}); err != nil {
			t.Fatal(err)
		}
	}

	runClear := func() string {
		t.Helper()
		var out bytes.Buffer
		root, err := bonfire.NewRoot("acme", RuntimeCommands(commandApp(t, dsn, nil), nil), &out)
		if err != nil {
			t.Fatal(err)
		}
		root.SetArgs([]string{"queue:clear"})
		if err := root.ExecuteContext(ctx); err != nil {
			t.Fatalf("queue:clear: %v\n%s", err, out.String())
		}
		return out.String()
	}
	out := runClear()
	if !strings.Contains(out, `Clearing queue "default"`) || !strings.Contains(out, "Cleared 2 jobs") {
		t.Fatalf("output = %q", out)
	}
	close(release)
	deadline := time.Now().Add(10 * time.Second)
	for countRows(t, gdb, `SELECT count(*) FROM river_job WHERE kind = ? AND state = 'completed'`, "conga_test_block") != 1 {
		if time.Now().After(deadline) {
			t.Fatal("running job did not complete after queue:clear")
		}
		time.Sleep(25 * time.Millisecond)
	}
	if n := countRows(t, gdb, `SELECT count(*) FROM river_job WHERE kind = ?`, "conga_test_ping"); n != 0 || pings.Load() != 0 {
		t.Fatalf("ping jobs left %d, ran %d", n, pings.Load())
	}
	if out := runClear(); !strings.Contains(out, "Cleared 0 jobs") {
		t.Fatalf("second clear output = %q", out)
	}
}

func runClearArgs(t *testing.T, dsn string, args ...string) string {
	t.Helper()
	var out bytes.Buffer
	root, err := bonfire.NewRoot("acme", RuntimeCommands(commandApp(t, dsn, nil), nil), &out)
	if err != nil {
		t.Fatal(err)
	}
	root.SetArgs(append([]string{"queue:clear"}, args...))
	if err := root.ExecuteContext(t.Context()); err != nil {
		t.Fatalf("queue:clear %v: %v\n%s", args, err, out.String())
	}
	return out.String()
}

// TestClearQueueStatesAndBatches covers the batch loop and the state
// filter of queue:clear without a worker: more than one 10000-row batch of
// available, scheduled and retryable jobs is cleared, and completed,
// discarded and other-queue jobs stay.
func TestClearQueueStatesAndBatches(t *testing.T) {
	db, dsn := migratedDB(t)
	_, gdb := testApp(t, db, dsn, nil)
	insert := func(n int, queue, state string) {
		t.Helper()
		q := `INSERT INTO river_job (args, kind, max_attempts, queue, state, scheduled_at, finalized_at)
			SELECT '{}'::jsonb, 'conga_test_ping', 3, ?, ?::river_job_state,
			       CASE WHEN ? = 'scheduled' THEN now() + interval '1 hour' ELSE now() END,
			       CASE WHEN ? IN ('completed', 'discarded', 'cancelled') THEN now() END
			FROM generate_series(1, ?)`
		if err := gdb.Exec(q, queue, state, state, state, n).Error; err != nil {
			t.Fatal(err)
		}
	}
	insert(clearBatch+1, "imports", "available")
	insert(3, "imports", "scheduled")
	insert(2, "imports", "retryable")
	insert(4, "imports", "completed")
	insert(1, "imports", "discarded")
	insert(5, "default", "available")

	out := runClearArgs(t, dsn, "imports")
	want := fmt.Sprintf("Cleared %d jobs", clearBatch+1+3+2)
	if !strings.Contains(out, `Clearing queue "imports"`) || !strings.Contains(out, want) {
		t.Fatalf("output = %q, want %q", out, want)
	}
	if n := countRows(t, gdb, `SELECT count(*) FROM river_job WHERE queue = 'imports'`); n != 5 {
		t.Fatalf("imports jobs left = %d, want the 5 finished ones", n)
	}
	if n := countRows(t, gdb, `SELECT count(*) FROM river_job WHERE queue = 'default'`); n != 5 {
		t.Fatalf("default jobs left = %d, want 5", n)
	}
	if out := runClearArgs(t, dsn, "  "); !strings.Contains(out, `Clearing queue "default"`) || !strings.Contains(out, "Cleared 5 jobs") {
		t.Fatalf("blank queue argument output = %q, want the default queue cleared", out)
	}
}

// syncBuffer is a bytes.Buffer safe for a command writing while the test
// reads.
type syncBuffer struct {
	mu  chan struct{}
	buf bytes.Buffer
}

func newSyncBuffer() *syncBuffer { return &syncBuffer{mu: make(chan struct{}, 1)} }

func (b *syncBuffer) Write(p []byte) (int, error) {
	b.mu <- struct{}{}
	defer func() { <-b.mu }()
	return b.buf.Write(p)
}

func (b *syncBuffer) String() string {
	b.mu <- struct{}{}
	defer func() { <-b.mu }()
	return b.buf.String()
}

// TestQueueWork covers CLI-06 and D-17: queue:work runs a filtered worker
// until its context ends and rejects unknown queues naming the known ones;
// serve runs a worker on every known queue unless queue.work_in_serve is
// false.
func TestQueueWork(t *testing.T) {
	_, dsn := migratedDB(t)

	t.Run("unknown_queue", func(t *testing.T) {
		var out bytes.Buffer
		root, err := bonfire.NewRoot("acme", RuntimeCommands(commandApp(t, dsn, nil), nil), &out)
		if err != nil {
			t.Fatal(err)
		}
		root.SetArgs([]string{"queue:work", "--queue", "nope"})
		err = root.ExecuteContext(t.Context())
		if err == nil || !strings.Contains(err.Error(), "known queues: default") {
			t.Fatalf("err = %v, want unknown queue listing known queues", err)
		}
	})

	t.Run("runs_until_cancelled", func(t *testing.T) {
		out := newSyncBuffer()
		root, err := bonfire.NewRoot("acme", RuntimeCommands(commandApp(t, dsn, nil), nil), out)
		if err != nil {
			t.Fatal(err)
		}
		root.SetArgs([]string{"queue:work", "--queue", "default"})
		ctx, cancel := context.WithCancel(t.Context())
		defer cancel()
		done := make(chan error, 1)
		go func() { done <- root.ExecuteContext(ctx) }()
		deadline := time.Now().Add(10 * time.Second)
		for !strings.Contains(out.String(), "worker started on queues: default") {
			if time.Now().After(deadline) {
				t.Fatalf("worker did not start: %q", out.String())
			}
			time.Sleep(25 * time.Millisecond)
		}
		cancel()
		select {
		case err := <-done:
			if err != nil {
				t.Fatalf("queue:work returned %v", err)
			}
		case <-time.After(15 * time.Second):
			t.Fatal("queue:work did not stop")
		}
	})

	t.Run("serve_worker", func(t *testing.T) {
		db, dsn := migratedDB(t)
		off, _ := testApp(t, db, dsn, map[string]any{"queue.work_in_serve": false})
		w, err := StartServeWorker(t.Context(), off, nil)
		if err != nil || w != nil {
			t.Fatalf("work_in_serve false: worker %v, err %v", w, err)
		}
		on, _ := testApp(t, db, dsn, nil)
		w, err = StartServeWorker(t.Context(), on, nil)
		if err != nil || w == nil {
			t.Fatalf("default: worker %v, err %v", w, err)
		}
		if got := w.Queues(); !reflect.DeepEqual(got, []string{"default", QueueScheduled}) {
			t.Fatalf("queues = %v", got)
		}
		if err := w.Stop(context.Background()); err != nil {
			t.Fatal(err)
		}
	})

	t.Run("only_named_queue_is_worked", func(t *testing.T) {
		db, dsn := migratedDB(t)
		app, gdb := testApp(t, db, dsn, map[string]any{"queue.queues.imports": 1})
		m, err := From(app)
		if err != nil {
			t.Fatal(err)
		}
		ran := make(chan string, 4)
		ping := Job(func(ctx context.Context, a pingArgs) error {
			ran <- a.Tag
			return nil
		})
		w := startTestWorker(t, app, WorkerOptions{Queues: []string{"imports"}}, ping)
		if got := w.Queues(); !reflect.DeepEqual(got, []string{"imports"}) {
			t.Fatalf("queues = %v", got)
		}
		ctx := t.Context()
		if err := m.Enqueue(ctx, gdb, pingArgs{Tag: "default"}, EnqueueOpts{}); err != nil {
			t.Fatal(err)
		}
		if err := m.Enqueue(ctx, gdb, pingArgs{Tag: "imports"}, EnqueueOpts{Queue: "imports"}); err != nil {
			t.Fatal(err)
		}
		select {
		case tag := <-ran:
			if tag != "imports" {
				t.Fatalf("worker ran the %s job", tag)
			}
		case <-time.After(5 * time.Second):
			t.Fatal("imports job did not run")
		}
		select {
		case tag := <-ran:
			t.Fatalf("worker filtered to imports ran the %s job", tag)
		case <-time.After(700 * time.Millisecond):
		}
		if n := countRows(t, gdb, `SELECT count(*) FROM river_job WHERE queue = 'default' AND state = 'available'`); n != 1 {
			t.Fatalf("default-queue jobs left available = %d, want 1", n)
		}
	})
}