package e2e

import (
	"bytes"
	"context"
	"database/sql"
	"image"
	"image/color"
	"image/png"
	"io/fs"
	"path/filepath"
	"testing"
	"time"

	assets "shared-album"
	"shared-album/internal/albums"
	"shared-album/internal/auth"
	"shared-album/internal/db"
	"shared-album/internal/photos"
	"shared-album/internal/sse"
	"shared-album/internal/storage"
	"shared-album/internal/store"
)

func makePNG(t *testing.T) []byte {
	t.Helper()
	img := image.NewRGBA(image.Rect(0, 0, 4, 4))
	for x := 0; x < 4; x++ {
		for y := 0; y < 4; y++ {
			img.Set(x, y, color.RGBA{R: uint8(x * 40), G: uint8(y * 40), B: 128, A: 255})
		}
	}
	var buf bytes.Buffer
	if err := png.Encode(&buf, img); err != nil {
		t.Fatalf("encode png: %v", err)
	}
	return buf.Bytes()
}

type stack struct {
	db     *sql.DB
	photos *photos.Service
	albums *albums.Service
	auth   *auth.Service
}

// openStack opens a migrated SQLite database at path and builds the services.
func openStack(t *testing.T, path, blobRoot string) (*stack, func()) {
	t.Helper()
	migFS, err := fs.Sub(assets.Migrations, "migrations/sqlite")
	if err != nil {
		t.Fatalf("migrations fs: %v", err)
	}
	if err := db.MigrateSQLite(path, migFS); err != nil {
		t.Fatalf("migrate: %v", err)
	}
	database, err := db.OpenSQLite(path)
	if err != nil {
		t.Fatalf("open: %v", err)
	}
	repos := store.NewSQLite(database)
	hub := sse.NewHub(1)
	signer, err := storage.NewSigner("http://app.test", "secret", time.Hour)
	if err != nil {
		t.Fatalf("signer: %v", err)
	}
	blob, err := storage.NewFS(blobRoot, signer)
	if err != nil {
		t.Fatalf("fs: %v", err)
	}
	authSvc := auth.NewService(repos.Auth, auth.NewTokenManager("secret", 15*time.Minute, time.Hour))
	albumsSvc := albums.NewService(repos.Albums, repos.Members, hub, blob)
	photosSvc := photos.NewService(repos.Photos, albumsSvc, blob, hub)
	return &stack{db: database, photos: photosSvc, albums: albumsSvc, auth: authSvc}, func() { database.Close() }
}

func TestSQLiteEndToEndWithRestart(t *testing.T) {
	ctx := context.Background()
	path := filepath.Join(t.TempDir(), "galo.db")
	blobs := t.TempDir()

	st, closeDB := openStack(t, path, blobs)
	worker := photos.NewWorker(st.photos, 20*time.Millisecond, 10, time.Minute)
	wctx, cancel := context.WithCancel(ctx)
	go worker.Run(wctx)

	user, _, err := st.auth.Register(ctx, "e2e@test.local", "password123", "E2E")
	if err != nil {
		t.Fatalf("register: %v", err)
	}
	album, err := st.albums.Create(ctx, user.ID, albums.CreateInput{Title: "Trip"})
	if err != nil {
		t.Fatalf("create album: %v", err)
	}
	p, err := st.photos.Upload(ctx, photos.UploadInput{AlbumID: album.ID, UserID: user.ID, Filename: "a.png", Data: makePNG(t)})
	if err != nil {
		t.Fatalf("upload: %v", err)
	}
	waitFor(t, "variants of first photo", func() bool {
		got, err := st.photos.Get(ctx, p.ID, user.ID)
		return err == nil && got.ThumbURL != "" && got.PreviewURL != ""
	})

	if err := st.photos.PermanentDelete(ctx, p.ID, user.ID); err != nil {
		t.Fatalf("permanent delete: %v", err)
	}
	waitFor(t, "garbage collection", func() bool {
		var n int
		return st.db.QueryRowContext(ctx, `SELECT count(*) FROM objects`).Scan(&n) == nil && n == 0
	})

	// Stop the worker, then queue another upload whose variant job must survive
	// the restart and be processed by a fresh worker over the same file.
	cancel()
	time.Sleep(50 * time.Millisecond)

	p2, err := st.photos.Upload(ctx, photos.UploadInput{AlbumID: album.ID, UserID: user.ID, Filename: "b.png", Data: makePNG(t)})
	if err != nil {
		t.Fatalf("upload p2: %v", err)
	}
	got2, _ := st.photos.Get(ctx, p2.ID, user.ID)
	if got2.PreviewURL != "" {
		t.Fatalf("variants generated before restart")
	}
	closeDB()

	st2, close2 := openStack(t, path, blobs)
	defer close2()
	worker2 := photos.NewWorker(st2.photos, 20*time.Millisecond, 10, time.Minute)
	wctx2, cancel2 := context.WithCancel(ctx)
	defer cancel2()
	go worker2.Run(wctx2)

	waitFor(t, "variants of second photo after restart", func() bool {
		got, err := st2.photos.Get(ctx, p2.ID, user.ID)
		return err == nil && got.ThumbURL != "" && got.PreviewURL != ""
	})
}

func waitFor(t *testing.T, what string, cond func() bool) {
	t.Helper()
	deadline := time.Now().Add(10 * time.Second)
	for time.Now().Before(deadline) {
		if cond() {
			return
		}
		time.Sleep(20 * time.Millisecond)
	}
	t.Fatalf("timed out waiting for %s", what)
}