Levyraati26_go/submit.go

package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"github.com/jackc/pgx/v5"
)

const (
	maxUploadBytes  = 50 << 20
	maxDuration     = 15 * time.Minute
	maxPerDay       = 5
	maxTitle        = 100
	maxArtist       = 100
	maxDescription  = 2000
	quotaWindowText = "24 tunnin"
)

// Fixed list, validated app-side. Not a table: it never changes without a code change anyway.
//
// The stored value is the English code and the Finnish label is display only — the same split the
// statuses use, so rewording a genre never touches a song row.
type genre struct {
	Code  string
	Label string
}

var genres = []genre{
	{"Rock", "Rock"},
	{"Metal", "Metal"},
	{"Punk", "Punk"},
	{"Blues", "Blues"},
	{"Jazz", "Jazz"},
	{"Electronic", "Elektroninen"},
	{"Hip Hop", "Hip hop"},
	{"Pop", "Pop"},
	{"Folk / Country", "Folk / Country"},
	{"Classical", "Klassinen"},
	{"Soundtrack", "Elokuvamusiikki"},
	{"Experimental", "Kokeellinen"},
	{"Finnish", "Kotimainen"},
	{"Just Plain Weird", "Ihan outoa"},
	{"Other", "Muu"},
}

func validGenre(code string) bool {
	return genreLabel(code) != ""
}

func genreLabel(code string) string {
	for _, g := range genres {
		if g.Code == code {
			return g.Label
		}
	}
	return ""
}

// ponytail: in-process goroutines, 2 at a time. A real queue is the upgrade if this ever needs to
// survive a restart mid-conversion or run on another box. Unbounded goroutines shelling out to
// ffmpeg is how one enthusiastic evening fork-bombs a small VPS.
var slots = make(chan struct{}, 2)

// The nullable metadata columns are read with coalesce and held as plain strings: templates
// indirect pointers when printing, so a nil *string would render as "<nil>" inside a form field.
type submission struct {
	ID          int64
	UserID      int64
	Status      string
	StatusMsg   *string
	SourceURL   *string
	TmpPath     string
	Title       string
	Artist      string
	Genre       string
	Description string
	CreatedAt   time.Time
}

func (s *submission) Ready() bool  { return s.Status == "ready" }
func (s *submission) Failed() bool { return s.Status == "failed" }
func (s *submission) Done() bool   { return s.Ready() || s.Failed() }

// Every status ships with its Finnish label, so the strings never leave Go.
func (s *submission) Label() string {
	switch s.Status {
	case "queued":
		return "Jonossa…"
	case "downloading":
		return "Ladataan…"
	case "converting":
		return "Muunnetaan…"
	case "ready":
		return "Valmis julkaistavaksi"
	case "failed":
		return "Epäonnistui"
	}
	return s.Status
}

func (s *submission) Genres() []genre { return genres }

// The chosen genre's Finnish label, for pages that show it rather than offer it.
func (s *submission) GenreLabel() string { return genreLabel(s.Genre) }

func (a *app) tmpPath(id int64, ext string) string {
	return filepath.Join(a.cfg.storageDir, "tmp", strconv.FormatInt(id, 10)+ext)
}

func (a *app) audioPath(songID int64) string {
	return filepath.Join(a.cfg.storageDir, "audio", strconv.FormatInt(songID, 10)+".ogg")
}

// --- submit ---

// The submit page also lists your own submissions still in flight, so one is reachable by
// something other than its URL.
func (a *app) submitPage(w http.ResponseWriter, r *http.Request) {
	a.submitError(w, r, http.StatusOK, "")
}

func (a *app) submitError(w http.ResponseWriter, r *http.Request, status int, msg string) {
	subs, err := a.mySubmissions(r.Context(), memberFrom(r.Context()).ID)
	if err != nil {
		slog.Error("list submissions", "ctx", "submissions", "error", err)
	}
	a.render(w, r, status, "submit.html",
		page{Title: "Lähetä kappale", Data: map[string]any{"Error": msg, "Submissions": subs}})
}

// Five submissions per rolling 24 hours. Failed ones never count: no audio, no submission, and
// yt-dlp breaking is not the submitter's fault. Published songs do count, so the row being gone
// from `submissions` is why this also looks at `songs`.
func (a *app) overQuota(ctx context.Context, userID int64) (bool, error) {
	var n int
	err := a.pool.QueryRow(ctx, `
		select (select count(*) from submissions
		         where user_id = $1 and status <> 'failed'
		           and created_at > now() - interval '24 hours')
		     + (select count(*) from songs
		         where submitted_by = $1 and created_at > now() - interval '24 hours')`,
		userID).Scan(&n)
	return n >= maxPerDay, err
}

func (a *app) submit(w http.ResponseWriter, r *http.Request) {
	m := memberFrom(r.Context())

	over, err := a.overQuota(r.Context(), m.ID)
	if err != nil {
		slog.Error("quota", "ctx", "submissions", "error", err)
		a.submitError(w, r, http.StatusInternalServerError, "Jokin meni pieleen.")
		return
	}
	if over {
		a.submitError(w, r, http.StatusTooManyRequests,
			fmt.Sprintf("Olet lähettänyt jo %d kappaletta viimeisen %s aikana. Yritä huomenna.",
				maxPerDay, quotaWindowText))
		return
	}

	r.Body = http.MaxBytesReader(w, r.Body, maxUploadBytes)
	file, header, err := r.FormFile("audio")
	if err != nil {
		a.submitError(w, r, http.StatusRequestEntityTooLarge,
			"Tiedostoa ei voitu lukea. Enintään 50 MB.")
		return
	}
	defer file.Close()

	var subID int64
	err = a.pool.QueryRow(r.Context(),
		`insert into submissions (user_id, status) values ($1, 'queued') returning id`,
		m.ID).Scan(&subID)
	if err != nil {
		slog.Error("create submission", "ctx", "submissions", "error", err)
		a.submitError(w, r, http.StatusInternalServerError, "Jokin meni pieleen.")
		return
	}

	// The row exists before the file does, so nothing on disk is ever unaccounted for.
	src := a.tmpPath(subID, filepath.Ext(header.Filename))
	dst, err := os.Create(src)
	if err == nil {
		_, err = io.Copy(dst, file)
		dst.Close()
	}
	if err != nil {
		slog.Error("save upload", "ctx", "submissions", "error", err, "submission", subID)
		a.discardSubmission(r.Context(), subID, src)
		a.submitError(w, r, http.StatusRequestEntityTooLarge,
			"Tiedostoa ei voitu tallentaa. Enintään 50 MB.")
		return
	}

	// Metadata is read synchronously: arriving later, it would land in a form the submitter is
	// already typing into and race their keystrokes.
	meta, err := probe(r.Context(), src)
	if err != nil {
		a.discardSubmission(r.Context(), subID, src)
		a.submitError(w, r, http.StatusUnprocessableEntity,
			"Tiedostosta ei löytynyt ääntä. Onko se varmasti äänitiedosto?")
		return
	}
	if meta.Duration > maxDuration {
		a.discardSubmission(r.Context(), subID, src)
		a.submitError(w, r, http.StatusUnprocessableEntity,
			"Kappale on yli 15 minuuttia pitkä.")
		return
	}

	if _, err := a.pool.Exec(r.Context(),
		`update submissions set tmp_path = $2, title = nullif($3, ''), artist = nullif($4, '')
		  where id = $1`, subID, src, meta.Title, meta.Artist); err != nil {
		slog.Error("save metadata", "ctx", "submissions", "error", err, "submission", subID)
	}

	slog.Info("submission received", "ctx", "submissions", "submission", subID, "user", m.ID)
	go a.convert(subID, src)
	http.Redirect(w, r, fmt.Sprintf("/submit/%d", subID), http.StatusSeeOther)
}

func (a *app) discardSubmission(ctx context.Context, subID int64, path string) {
	if path != "" {
		os.Remove(path)
	}
	if _, err := a.pool.Exec(ctx, `delete from submissions where id = $1`, subID); err != nil {
		slog.Error("discard submission", "ctx", "submissions", "error", err, "submission", subID)
	}
}

// --- convert ---

func (a *app) convert(subID int64, src string) {
	slots <- struct{}{}
	defer func() { <-slots }()

	// Detached from the request: the submitter's browser is long gone by now.
	ctx := context.Background()
	a.setStatus(ctx, subID, "converting", "")

	out := a.tmpPath(subID, ".ogg")
	msg, err := convertToOpus(ctx, src, out)
	if err != nil {
		os.Remove(out)
		if msg == "" {
			msg = err.Error()
		}
		a.setStatus(ctx, subID, "failed", msg)
		slog.Warn("conversion failed", "ctx", "submissions", "submission", subID, "error", err)
		return
	}
	// The original is discarded as soon as the Opus exists.
	os.Remove(src)

	if _, err := a.pool.Exec(ctx,
		`update submissions set status = 'ready', status_msg = null, tmp_path = $2 where id = $1`,
		subID, out); err != nil {
		slog.Error("mark ready", "ctx", "submissions", "error", err, "submission", subID)
		return
	}
	slog.Info("conversion ready", "ctx", "submissions", "submission", subID)
}

func (a *app) setStatus(ctx context.Context, subID int64, status, msg string) {
	if _, err := a.pool.Exec(ctx,
		`update submissions set status = $2, status_msg = nullif($3, '') where id = $1`,
		subID, status, msg); err != nil {
		slog.Error("set status", "ctx", "submissions", "error", err, "submission", subID)
	}
}

// --- the waiting page ---

// Submitter-only: a submission is invisible to everyone else, including a failed one.
func (a *app) loadSubmission(w http.ResponseWriter, r *http.Request) *submission {
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		http.NotFound(w, r)
		return nil
	}
	var s submission
	err = a.pool.QueryRow(r.Context(), `
		select id, user_id, status, status_msg, source_url, coalesce(tmp_path, ''),
		       coalesce(title, ''), coalesce(artist, ''), coalesce(genre, ''),
		       coalesce(description, ''), created_at
		  from submissions where id = $1`, id).
		Scan(&s.ID, &s.UserID, &s.Status, &s.StatusMsg, &s.SourceURL, &s.TmpPath,
			&s.Title, &s.Artist, &s.Genre, &s.Description, &s.CreatedAt)
	if errors.Is(err, pgx.ErrNoRows) {
		http.NotFound(w, r)
		return nil
	} else if err != nil {
		slog.Error("load submission", "ctx", "submissions", "error", err)
		http.Error(w, "virhe", http.StatusInternalServerError)
		return nil
	}
	if s.UserID != memberFrom(r.Context()).ID {
		http.NotFound(w, r)
		return nil
	}
	return &s
}

func (a *app) submissionPage(w http.ResponseWriter, r *http.Request) {
	s := a.loadSubmission(w, r)
	if s == nil {
		return
	}
	a.render(w, r, http.StatusOK, "submission.html", page{Title: "Lähetys", Data: s})
}

// The same partial the page includes on first paint, returned alone for the HTMX poll — so the
// markup exists once and arrives already populated. HTMX stops polling when the fragment drops
// hx-trigger, which it does on a terminal status.
func (a *app) submissionStatus(w http.ResponseWriter, r *http.Request) {
	s := a.loadSubmission(w, r)
	if s == nil {
		return
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	if err := pages["submission.html"].ExecuteTemplate(w, "submission-status", s); err != nil {
		slog.Error("render status", "ctx", "submissions", "error", err)
	}
}

// Metadata is editable while the conversion runs — that is the point of the waiting page. There is
// no save button: HTMX posts here after a pause in typing, and pressing Julkaise posts the same
// fields to publish, so a browser without JS loses nothing.
func (a *app) saveMetadata(ctx context.Context, subID int64, r *http.Request) error {
	genre := r.FormValue("genre")
	if genre != "" && !validGenre(genre) {
		return fmt.Errorf("unknown genre %q", genre)
	}
	_, err := a.pool.Exec(ctx, `
		update submissions set title = nullif($2, ''), artist = nullif($3, ''),
		       genre = nullif($4, ''), description = nullif($5, '')
		 where id = $1`,
		subID,
		clean(r.FormValue("title"), maxTitle),
		clean(r.FormValue("artist"), maxArtist),
		genre,
		clean(r.FormValue("description"), maxDescription))
	return err
}

func (a *app) saveSubmission(w http.ResponseWriter, r *http.Request) {
	s := a.loadSubmission(w, r)
	if s == nil {
		return
	}
	if err := a.saveMetadata(r.Context(), s.ID, r); err != nil {
		slog.Error("save submission", "ctx", "submissions", "error", err, "submission", s.ID)
		http.Error(w, "virhe", http.StatusUnprocessableEntity)
		return
	}
	// The autosave answers with the "saved at" line and nothing else; a plain POST (no JS) goes
	// back to the page.
	if r.Header.Get("HX-Request") == "" {
		http.Redirect(w, r, fmt.Sprintf("/submit/%d", s.ID), http.StatusSeeOther)
		return
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	if err := pages["submission.html"].ExecuteTemplate(w, "saved",
		time.Now().Local().Format("15.04")); err != nil {
		slog.Error("render saved", "ctx", "submissions", "error", err)
	}
}

// --- publish ---

func (a *app) publish(w http.ResponseWriter, r *http.Request) {
	s := a.loadSubmission(w, r)
	if s == nil {
		return
	}
	if !s.Ready() {
		http.Error(w, "ei vielä valmis", http.StatusConflict)
		return
	}

	// Julkaise submits the metadata form, so the last keystrokes arrive with it — the autosave is
	// a convenience, not the only path.
	if r.FormValue("title") != "" || r.FormValue("artist") != "" || r.FormValue("genre") != "" {
		if err := a.saveMetadata(r.Context(), s.ID, r); err != nil {
			slog.Error("save before publish", "ctx", "submissions", "error", err, "submission", s.ID)
			http.Error(w, "virhe", http.StatusUnprocessableEntity)
			return
		}
		if s = a.loadSubmission(w, r); s == nil {
			return
		}
	}

	// Title, artist and genre are required here rather than at submit: the form is meant to be
	// filled while the conversion runs, and prefill can legitimately produce nothing.
	title, artist, genre := clean(s.Title, maxTitle), clean(s.Artist, maxArtist), s.Genre
	if title == "" || artist == "" || !validGenre(genre) {
		a.flash(w, "Täytä nimi, esittäjä ja genre ennen julkaisua.")
		http.Redirect(w, r, fmt.Sprintf("/submit/%d", s.ID), http.StatusSeeOther)
		return
	}

	src := s.TmpPath
	meta, err := probe(r.Context(), src)
	if err != nil {
		slog.Error("probe before publish", "ctx", "submissions", "error", err, "submission", s.ID)
		a.flash(w, "Äänitiedostoa ei löytynyt. Lähetä kappale uudelleen.")
		http.Redirect(w, r, fmt.Sprintf("/submit/%d", s.ID), http.StatusSeeOther)
		return
	}

	tx, err := a.pool.Begin(r.Context())
	if err != nil {
		slog.Error("begin publish", "ctx", "submissions", "error", err)
		http.Error(w, "virhe", http.StatusInternalServerError)
		return
	}
	defer tx.Rollback(r.Context())

	var songID int64
	err = tx.QueryRow(r.Context(), `
		insert into songs (title, artist, genre, description, audio_file, duration_seconds,
		                   source_url, submitted_by)
		values ($1, $2, $3, $4, '', $5, $6, $7) returning id`,
		title, artist, genre, nilIfEmpty(clean(s.Description, maxDescription)),
		int(meta.Duration.Seconds()), s.SourceURL, s.UserID).Scan(&songID)
	if err != nil {
		slog.Error("insert song", "ctx", "songs", "error", err, "submission", s.ID)
		http.Error(w, "virhe", http.StatusInternalServerError)
		return
	}

	// The rename is inside the transaction: if the file move fails, the song row never existed.
	// A crash between rename and commit leaves an orphan .ogg — the startup sweep gets it.
	dst := a.audioPath(songID)
	if err := os.Rename(src, dst); err != nil {
		slog.Error("move audio", "ctx", "songs", "error", err, "submission", s.ID)
		http.Error(w, "virhe", http.StatusInternalServerError)
		return
	}
	if _, err := tx.Exec(r.Context(),
		`update songs set audio_file = $2 where id = $1`,
		songID, filepath.Base(dst)); err != nil {
		os.Rename(dst, src)
		slog.Error("set audio file", "ctx", "songs", "error", err, "song", songID)
		http.Error(w, "virhe", http.StatusInternalServerError)
		return
	}
	if _, err := tx.Exec(r.Context(), `delete from submissions where id = $1`, s.ID); err != nil {
		os.Rename(dst, src)
		slog.Error("delete submission", "ctx", "submissions", "error", err, "submission", s.ID)
		http.Error(w, "virhe", http.StatusInternalServerError)
		return
	}
	if err := tx.Commit(r.Context()); err != nil {
		os.Rename(dst, src)
		slog.Error("commit publish", "ctx", "songs", "error", err, "submission", s.ID)
		http.Error(w, "virhe", http.StatusInternalServerError)
		return
	}

	slog.Info("song published", "ctx", "songs", "song", songID, "user", s.UserID)
	a.flash(w, "Kappale julkaistu.")
	http.Redirect(w, r, "/", http.StatusSeeOther)
}

// A failed submission is denied in every sense that matters: invisible to everyone but its
// submitter and never in `songs`. Discard removes the row and its temp file.
func (a *app) discard(w http.ResponseWriter, r *http.Request) {
	s := a.loadSubmission(w, r)
	if s == nil {
		return
	}
	a.discardSubmission(r.Context(), s.ID, s.TmpPath)
	os.Remove(a.tmpPath(s.ID, ".ogg"))
	a.flash(w, "Lähetys poistettu.")
	http.Redirect(w, r, "/", http.StatusSeeOther)
}

func nilIfEmpty(s string) *string {
	if strings.TrimSpace(s) == "" {
		return nil
	}
	return &s
}

// Own in-flight submissions, for the home page — otherwise a submission is only reachable by URL.
func (a *app) mySubmissions(ctx context.Context, userID int64) ([]*submission, error) {
	rows, err := a.pool.Query(ctx, `
		select id, user_id, status, status_msg, source_url, coalesce(tmp_path, ''),
		       coalesce(title, ''), coalesce(artist, ''), coalesce(genre, ''),
		       coalesce(description, ''), created_at
		  from submissions where user_id = $1 order by created_at desc`, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []*submission
	for rows.Next() {
		var s submission
		if err := rows.Scan(&s.ID, &s.UserID, &s.Status, &s.StatusMsg, &s.SourceURL, &s.TmpPath,
			&s.Title, &s.Artist, &s.Genre, &s.Description, &s.CreatedAt); err != nil {
			return nil, err
		}
		out = append(out, &s)
	}
	return out, rows.Err()
}