chore: base project skeleton and db schema

2026-04-06 07:03:22 +02:00
commit ccad63eb7f
13 changed files with 1353 additions and 0 deletions
--- a/internal/database/db.go
+++ b/internal/database/db.go
@@ -0,0 +1,31 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.30.0
+
+package database
+
+import (
+	"context"
+	"database/sql"
+)
+
+type DBTX interface {
+	ExecContext(context.Context, string, ...interface{}) (sql.Result, error)
+	PrepareContext(context.Context, string) (*sql.Stmt, error)
+	QueryContext(context.Context, string, ...interface{}) (*sql.Rows, error)
+	QueryRowContext(context.Context, string, ...interface{}) *sql.Row
+}
+
+func New(db DBTX) *Queries {
+	return &Queries{db: db}
+}
+
+type Queries struct {
+	db DBTX
+}
+
+func (q *Queries) WithTx(tx *sql.Tx) *Queries {
+	return &Queries{
+		db: tx,
+	}
+}
--- a/internal/database/models.go
+++ b/internal/database/models.go
@@ -0,0 +1,47 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.30.0
+
+package database
+
+import (
+	"time"
+)
+
+type Account struct {
+	ID                string    `json:"id"`
+	UserID            string    `json:"user_id"`
+	Provider          string    `json:"provider"`
+	ProviderAccountID string    `json:"provider_account_id"`
+	CreatedAt         time.Time `json:"created_at"`
+}
+
+type Anime struct {
+	ID        int64     `json:"id"`
+	Title     string    `json:"title"`
+	ImageUrl  string    `json:"image_url"`
+	CreatedAt time.Time `json:"created_at"`
+}
+
+type Session struct {
+	ID        string    `json:"id"`
+	UserID    string    `json:"user_id"`
+	ExpiresAt time.Time `json:"expires_at"`
+	CreatedAt time.Time `json:"created_at"`
+}
+
+type User struct {
+	ID           string    `json:"id"`
+	Username     string    `json:"username"`
+	PasswordHash string    `json:"password_hash"`
+	CreatedAt    time.Time `json:"created_at"`
+}
+
+type WatchListEntry struct {
+	ID        string    `json:"id"`
+	UserID    string    `json:"user_id"`
+	AnimeID   int64     `json:"anime_id"`
+	Status    string    `json:"status"`
+	CreatedAt time.Time `json:"created_at"`
+	UpdatedAt time.Time `json:"updated_at"`
+}
--- a/internal/database/querier.go
+++ b/internal/database/querier.go
@@ -0,0 +1,26 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.30.0
+
+package database
+
+import (
+	"context"
+)
+
+type Querier interface {
+	CreateSession(ctx context.Context, arg CreateSessionParams) (Session, error)
+	CreateUser(ctx context.Context, arg CreateUserParams) (User, error)
+	DeleteSession(ctx context.Context, id string) error
+	DeleteUserSessions(ctx context.Context, userID string) error
+	DeleteWatchListEntry(ctx context.Context, arg DeleteWatchListEntryParams) error
+	GetSession(ctx context.Context, id string) (Session, error)
+	GetUser(ctx context.Context, id string) (User, error)
+	GetUserByUsername(ctx context.Context, username string) (User, error)
+	GetUserWatchList(ctx context.Context, userID string) ([]GetUserWatchListRow, error)
+	GetWatchListEntry(ctx context.Context, arg GetWatchListEntryParams) (WatchListEntry, error)
+	UpsertAnime(ctx context.Context, arg UpsertAnimeParams) (Anime, error)
+	UpsertWatchListEntry(ctx context.Context, arg UpsertWatchListEntryParams) (WatchListEntry, error)
+}
+
+var _ Querier = (*Queries)(nil)
--- a/internal/database/queries.sql
+++ b/internal/database/queries.sql
@@ -0,0 +1,55 @@
+-- name: GetUser :one
+SELECT * FROM user WHERE id = ? LIMIT 1;
+
+-- name: GetUserByUsername :one
+SELECT * FROM user WHERE username = ? LIMIT 1;
+
+-- name: CreateUser :one
+INSERT INTO user (id, username, password_hash)
+VALUES (?, ?, ?)
+RETURNING *;
+
+-- name: CreateSession :one
+INSERT INTO session (id, user_id, expires_at)
+VALUES (?, ?, ?)
+RETURNING *;
+
+-- name: GetSession :one
+SELECT * FROM session WHERE id = ? LIMIT 1;
+
+-- name: DeleteSession :exec
+DELETE FROM session WHERE id = ?;
+
+-- name: DeleteUserSessions :exec
+DELETE FROM session WHERE user_id = ?;
+
+-- name: UpsertAnime :one
+INSERT INTO anime (id, title, image_url)
+VALUES (?, ?, ?)
+ON CONFLICT (id) DO UPDATE SET
+    title = excluded.title,
+    image_url = excluded.image_url
+RETURNING *;
+
+-- name: UpsertWatchListEntry :one
+INSERT INTO watch_list_entry (id, user_id, anime_id, status, updated_at)
+VALUES (?, ?, ?, ?, CURRENT_TIMESTAMP)
+ON CONFLICT (user_id, anime_id) DO UPDATE SET
+    status = excluded.status,
+    updated_at = CURRENT_TIMESTAMP
+RETURNING *;
+
+-- name: GetWatchListEntry :one
+SELECT * FROM watch_list_entry
+WHERE user_id = ? AND anime_id = ? LIMIT 1;
+
+-- name: GetUserWatchList :many
+SELECT e.*, a.title, a.image_url
+FROM watch_list_entry e
+JOIN anime a ON e.anime_id = a.id
+WHERE e.user_id = ?
+ORDER BY e.updated_at DESC;
+
+-- name: DeleteWatchListEntry :exec
+DELETE FROM watch_list_entry
+WHERE user_id = ? AND anime_id = ?;
--- a/internal/database/queries.sql.go
+++ b/internal/database/queries.sql.go
@@ -0,0 +1,277 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.30.0
+// source: queries.sql
+
+package database
+
+import (
+	"context"
+	"time"
+)
+
+const createSession = `-- name: CreateSession :one
+INSERT INTO session (id, user_id, expires_at)
+VALUES (?, ?, ?)
+RETURNING id, user_id, expires_at, created_at
+`
+
+type CreateSessionParams struct {
+	ID        string    `json:"id"`
+	UserID    string    `json:"user_id"`
+	ExpiresAt time.Time `json:"expires_at"`
+}
+
+func (q *Queries) CreateSession(ctx context.Context, arg CreateSessionParams) (Session, error) {
+	row := q.db.QueryRowContext(ctx, createSession, arg.ID, arg.UserID, arg.ExpiresAt)
+	var i Session
+	err := row.Scan(
+		&i.ID,
+		&i.UserID,
+		&i.ExpiresAt,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const createUser = `-- name: CreateUser :one
+INSERT INTO user (id, username, password_hash)
+VALUES (?, ?, ?)
+RETURNING id, username, password_hash, created_at
+`
+
+type CreateUserParams struct {
+	ID           string `json:"id"`
+	Username     string `json:"username"`
+	PasswordHash string `json:"password_hash"`
+}
+
+func (q *Queries) CreateUser(ctx context.Context, arg CreateUserParams) (User, error) {
+	row := q.db.QueryRowContext(ctx, createUser, arg.ID, arg.Username, arg.PasswordHash)
+	var i User
+	err := row.Scan(
+		&i.ID,
+		&i.Username,
+		&i.PasswordHash,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const deleteSession = `-- name: DeleteSession :exec
+DELETE FROM session WHERE id = ?
+`
+
+func (q *Queries) DeleteSession(ctx context.Context, id string) error {
+	_, err := q.db.ExecContext(ctx, deleteSession, id)
+	return err
+}
+
+const deleteUserSessions = `-- name: DeleteUserSessions :exec
+DELETE FROM session WHERE user_id = ?
+`
+
+func (q *Queries) DeleteUserSessions(ctx context.Context, userID string) error {
+	_, err := q.db.ExecContext(ctx, deleteUserSessions, userID)
+	return err
+}
+
+const deleteWatchListEntry = `-- name: DeleteWatchListEntry :exec
+DELETE FROM watch_list_entry
+WHERE user_id = ? AND anime_id = ?
+`
+
+type DeleteWatchListEntryParams struct {
+	UserID  string `json:"user_id"`
+	AnimeID int64  `json:"anime_id"`
+}
+
+func (q *Queries) DeleteWatchListEntry(ctx context.Context, arg DeleteWatchListEntryParams) error {
+	_, err := q.db.ExecContext(ctx, deleteWatchListEntry, arg.UserID, arg.AnimeID)
+	return err
+}
+
+const getSession = `-- name: GetSession :one
+SELECT id, user_id, expires_at, created_at FROM session WHERE id = ? LIMIT 1
+`
+
+func (q *Queries) GetSession(ctx context.Context, id string) (Session, error) {
+	row := q.db.QueryRowContext(ctx, getSession, id)
+	var i Session
+	err := row.Scan(
+		&i.ID,
+		&i.UserID,
+		&i.ExpiresAt,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const getUser = `-- name: GetUser :one
+SELECT id, username, password_hash, created_at FROM user WHERE id = ? LIMIT 1
+`
+
+func (q *Queries) GetUser(ctx context.Context, id string) (User, error) {
+	row := q.db.QueryRowContext(ctx, getUser, id)
+	var i User
+	err := row.Scan(
+		&i.ID,
+		&i.Username,
+		&i.PasswordHash,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const getUserByUsername = `-- name: GetUserByUsername :one
+SELECT id, username, password_hash, created_at FROM user WHERE username = ? LIMIT 1
+`
+
+func (q *Queries) GetUserByUsername(ctx context.Context, username string) (User, error) {
+	row := q.db.QueryRowContext(ctx, getUserByUsername, username)
+	var i User
+	err := row.Scan(
+		&i.ID,
+		&i.Username,
+		&i.PasswordHash,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const getUserWatchList = `-- name: GetUserWatchList :many
+SELECT e.id, e.user_id, e.anime_id, e.status, e.created_at, e.updated_at, a.title, a.image_url
+FROM watch_list_entry e
+JOIN anime a ON e.anime_id = a.id
+WHERE e.user_id = ?
+ORDER BY e.updated_at DESC
+`
+
+type GetUserWatchListRow struct {
+	ID        string    `json:"id"`
+	UserID    string    `json:"user_id"`
+	AnimeID   int64     `json:"anime_id"`
+	Status    string    `json:"status"`
+	CreatedAt time.Time `json:"created_at"`
+	UpdatedAt time.Time `json:"updated_at"`
+	Title     string    `json:"title"`
+	ImageUrl  string    `json:"image_url"`
+}
+
+func (q *Queries) GetUserWatchList(ctx context.Context, userID string) ([]GetUserWatchListRow, error) {
+	rows, err := q.db.QueryContext(ctx, getUserWatchList, userID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []GetUserWatchListRow
+	for rows.Next() {
+		var i GetUserWatchListRow
+		if err := rows.Scan(
+			&i.ID,
+			&i.UserID,
+			&i.AnimeID,
+			&i.Status,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+			&i.Title,
+			&i.ImageUrl,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Close(); err != nil {
+		return nil, err
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const getWatchListEntry = `-- name: GetWatchListEntry :one
+SELECT id, user_id, anime_id, status, created_at, updated_at FROM watch_list_entry
+WHERE user_id = ? AND anime_id = ? LIMIT 1
+`
+
+type GetWatchListEntryParams struct {
+	UserID  string `json:"user_id"`
+	AnimeID int64  `json:"anime_id"`
+}
+
+func (q *Queries) GetWatchListEntry(ctx context.Context, arg GetWatchListEntryParams) (WatchListEntry, error) {
+	row := q.db.QueryRowContext(ctx, getWatchListEntry, arg.UserID, arg.AnimeID)
+	var i WatchListEntry
+	err := row.Scan(
+		&i.ID,
+		&i.UserID,
+		&i.AnimeID,
+		&i.Status,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+	)
+	return i, err
+}
+
+const upsertAnime = `-- name: UpsertAnime :one
+INSERT INTO anime (id, title, image_url)
+VALUES (?, ?, ?)
+ON CONFLICT (id) DO UPDATE SET
+    title = excluded.title,
+    image_url = excluded.image_url
+RETURNING id, title, image_url, created_at
+`
+
+type UpsertAnimeParams struct {
+	ID       int64  `json:"id"`
+	Title    string `json:"title"`
+	ImageUrl string `json:"image_url"`
+}
+
+func (q *Queries) UpsertAnime(ctx context.Context, arg UpsertAnimeParams) (Anime, error) {
+	row := q.db.QueryRowContext(ctx, upsertAnime, arg.ID, arg.Title, arg.ImageUrl)
+	var i Anime
+	err := row.Scan(
+		&i.ID,
+		&i.Title,
+		&i.ImageUrl,
+		&i.CreatedAt,
+	)
+	return i, err
+}
+
+const upsertWatchListEntry = `-- name: UpsertWatchListEntry :one
+INSERT INTO watch_list_entry (id, user_id, anime_id, status, updated_at)
+VALUES (?, ?, ?, ?, CURRENT_TIMESTAMP)
+ON CONFLICT (user_id, anime_id) DO UPDATE SET
+    status = excluded.status,
+    updated_at = CURRENT_TIMESTAMP
+RETURNING id, user_id, anime_id, status, created_at, updated_at
+`
+
+type UpsertWatchListEntryParams struct {
+	ID      string `json:"id"`
+	UserID  string `json:"user_id"`
+	AnimeID int64  `json:"anime_id"`
+	Status  string `json:"status"`
+}
+
+func (q *Queries) UpsertWatchListEntry(ctx context.Context, arg UpsertWatchListEntryParams) (WatchListEntry, error) {
+	row := q.db.QueryRowContext(ctx, upsertWatchListEntry,
+		arg.ID,
+		arg.UserID,
+		arg.AnimeID,
+		arg.Status,
+	)
+	var i WatchListEntry
+	err := row.Scan(
+		&i.ID,
+		&i.UserID,
+		&i.AnimeID,
+		&i.Status,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+	)
+	return i, err
+}
--- a/internal/jikan/client.go
+++ b/internal/jikan/client.go
@@ -0,0 +1,235 @@
+package jikan
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/hashicorp/golang-lru/v2/expirable"
+)
+
+type SearchResult struct {
+	Animes      []Anime
+	HasNextPage bool
+}
+
+type TopAnimeResult struct {
+	Animes      []Anime
+	HasNextPage bool
+}
+
+type Client struct {
+	httpClient     *http.Client
+	baseURL        string
+	cache          *expirable.LRU[string, SearchResult]
+	topCache       *expirable.LRU[int, TopAnimeResult]
+	animeCache     *expirable.LRU[int, Anime]
+	relationsCache *expirable.LRU[int, JikanRelationsResponse]
+}
+
+func NewClient() *Client {
+	cache := expirable.NewLRU[string, SearchResult](500, nil, time.Hour*1)
+	topCache := expirable.NewLRU[int, TopAnimeResult](100, nil, time.Hour*1)
+	animeCache := expirable.NewLRU[int, Anime](1000, nil, time.Hour*24)
+	relationsCache := expirable.NewLRU[int, JikanRelationsResponse](1000, nil, time.Hour*24)
+
+	return &Client{
+		httpClient:     &http.Client{Timeout: 10 * time.Second},
+		baseURL:        "https://api.jikan.moe/v4",
+		cache:          cache,
+		topCache:       topCache,
+		animeCache:     animeCache,
+		relationsCache: relationsCache,
+	}
+}
+
+// fetchWithRetry provides robust fetching respecting Jikan's strict 3 req/sec rate limit
+func (c *Client) fetchWithRetry(urlStr string, out interface{}) error {
+	maxRetries := 3
+	for i := 0; i < maxRetries; i++ {
+		// Base delay for Jikan rate limiting (3 requests per second)
+		time.Sleep(340 * time.Millisecond)
+
+		resp, err := c.httpClient.Get(urlStr)
+		if err != nil {
+			return fmt.Errorf("jikan api error: %w", err)
+		}
+
+		if resp.StatusCode == 429 {
+			resp.Body.Close()
+			time.Sleep(800 * time.Millisecond) // Double delay on rate limit
+			continue
+		}
+
+		if resp.StatusCode != http.StatusOK {
+			resp.Body.Close()
+			return fmt.Errorf("jikan api returned status %d", resp.StatusCode)
+		}
+
+		err = json.NewDecoder(resp.Body).Decode(out)
+		resp.Body.Close()
+		return err
+	}
+	return fmt.Errorf("max retries exceeded for %s", urlStr)
+}
+
+// Search returns the anime list with pagination support
+func (c *Client) Search(query string, page int) (SearchResult, error) {
+	if query == "" {
+		return SearchResult{}, nil
+	}
+	if page < 1 {
+		page = 1
+	}
+
+	cacheKey := fmt.Sprintf("search:%s:%d", query, page)
+	if cached, ok := c.cache.Get(cacheKey); ok {
+		return cached, nil
+	}
+
+	var result SearchResponse
+	reqURL := fmt.Sprintf("%s/anime?q=%s&page=%d", c.baseURL, url.QueryEscape(query), page)
+	if err := c.fetchWithRetry(reqURL, &result); err != nil {
+		return SearchResult{}, err
+	}
+
+	res := SearchResult{
+		Animes:      result.Data,
+		HasNextPage: result.Pagination.HasNextPage,
+	}
+
+	c.cache.Add(cacheKey, res)
+	return res, nil
+}
+
+// GetTopAnime fetches the top anime by popularity
+func (c *Client) GetTopAnime(page int) (TopAnimeResult, error) {
+	if page < 1 {
+		page = 1
+	}
+	if cached, ok := c.topCache.Get(page); ok {
+		return cached, nil
+	}
+
+	var result TopAnimeResponse
+	reqURL := fmt.Sprintf("%s/top/anime?filter=bypopularity&page=%d", c.baseURL, page)
+	if err := c.fetchWithRetry(reqURL, &result); err != nil {
+		return TopAnimeResult{}, err
+	}
+
+	res := TopAnimeResult{
+		Animes:      result.Data,
+		HasNextPage: result.Pagination.HasNextPage,
+	}
+
+	c.topCache.Add(page, res)
+	return res, nil
+}
+
+// GetAnimeByID fetches full details for a single anime
+func (c *Client) GetAnimeByID(id int) (Anime, error) {
+	if cached, ok := c.animeCache.Get(id); ok {
+		return cached, nil
+	}
+
+	var result AnimeResponse
+	reqURL := fmt.Sprintf("%s/anime/%d/full", c.baseURL, id)
+	if err := c.fetchWithRetry(reqURL, &result); err != nil {
+		return Anime{}, err
+	}
+
+	c.animeCache.Add(id, result.Data)
+	return result.Data, nil
+}
+
+// GetRelationsData fetches the raw relationships for an anime
+func (c *Client) GetRelationsData(id int) (JikanRelationsResponse, error) {
+	if cached, ok := c.relationsCache.Get(id); ok {
+		return cached, nil
+	}
+
+	var result JikanRelationsResponse
+	reqURL := fmt.Sprintf("%s/anime/%d/relations", c.baseURL, id)
+	if err := c.fetchWithRetry(reqURL, &result); err != nil {
+		return JikanRelationsResponse{}, err
+	}
+
+	c.relationsCache.Add(id, result)
+	return result, nil
+}
+
+// findFirstAnimeRelation extracts the first related anime ID for a specific relation type
+func findFirstAnimeRelation(res JikanRelationsResponse, relType string) *int {
+	for _, group := range res.Data {
+		if group.Relation == relType {
+			for _, entry := range group.Entry {
+				if entry.Type == "anime" {
+					id := entry.MalID
+					return &id
+				}
+			}
+		}
+	}
+	return nil
+}
+
+// fetchChain recursively builds the relational chain (Prequels or Sequels)
+func (c *Client) fetchChain(startID int, direction string, visited map[int]bool) []RelationEntry {
+	rels, err := c.GetRelationsData(startID)
+	if err != nil {
+		return nil
+	}
+
+	nextIDPtr := findFirstAnimeRelation(rels, direction)
+	if nextIDPtr == nil {
+		return nil
+	}
+
+	nextID := *nextIDPtr
+	if visited[nextID] { // prevent loops
+		return nil
+	}
+	visited[nextID] = true
+
+	anime, err := c.GetAnimeByID(nextID)
+	if err != nil {
+		return nil
+	}
+
+	entry := RelationEntry{Anime: anime, IsCurrent: false}
+	rest := c.fetchChain(nextID, direction, visited)
+
+	if direction == "Prequel" {
+		return append(rest, entry)
+	}
+	return append([]RelationEntry{entry}, rest...)
+}
+
+// GetFullRelations resolves the full Prequel/Sequel chronological chain synchronously
+func (c *Client) GetFullRelations(id int) []RelationEntry {
+	currentAnime, err := c.GetAnimeByID(id)
+	if err != nil {
+		return nil
+	}
+
+	visited := map[int]bool{id: true}
+
+	prequels := c.fetchChain(id, "Prequel", visited)
+
+	// Clone visited set for sequels so we don't block valid paths if there's weird branching
+	visitedSeq := make(map[int]bool)
+	for k, v := range visited {
+		visitedSeq[k] = v
+	}
+
+	sequels := c.fetchChain(id, "Sequel", visitedSeq)
+
+	var result []RelationEntry
+	result = append(result, prequels...)
+	result = append(result, RelationEntry{Anime: currentAnime, IsCurrent: true})
+	result = append(result, sequels...)
+
+	return result
+}
--- a/internal/jikan/types.go
+++ b/internal/jikan/types.go
@@ -0,0 +1,75 @@
+package jikan
+
+// Anime struct matching the Jikan v4 API structure
+type Anime struct {
+	MalID         int    `json:"mal_id"`
+	Title         string `json:"title"`
+	TitleEnglish  string `json:"title_english"`
+	TitleJapanese string `json:"title_japanese"`
+	Images        struct {
+		Webp struct {
+			LargeImageURL string `json:"large_image_url"`
+		} `json:"webp"`
+	} `json:"images"`
+	Synopsis   string  `json:"synopsis"`
+	Score      float64 `json:"score"`
+	ScoredBy   int     `json:"scored_by"`
+	Rank       int     `json:"rank"`
+	Popularity int     `json:"popularity"`
+	Status     string  `json:"status"`
+	Episodes   int     `json:"episodes"`
+	Season     string  `json:"season"`
+	Year       int     `json:"year"`
+	Type       string  `json:"type"`
+}
+
+type AnimeResponse struct {
+	Data Anime `json:"data"`
+}
+
+type SearchResponse struct {
+	Data       []Anime    `json:"data"`
+	Pagination Pagination `json:"pagination"`
+}
+
+type Pagination struct {
+	HasNextPage bool `json:"has_next_page"`
+}
+
+type TopAnimeResponse struct {
+	Data       []Anime    `json:"data"`
+	Pagination Pagination `json:"pagination"`
+}
+
+// Relation Types
+type JikanRelationEntry struct {
+	MalID int    `json:"mal_id"`
+	Type  string `json:"type"`
+	Name  string `json:"name"`
+	URL   string `json:"url"`
+}
+
+type JikanRelationGroup struct {
+	Relation string               `json:"relation"`
+	Entry    []JikanRelationEntry `json:"entry"`
+}
+
+type JikanRelationsResponse struct {
+	Data []JikanRelationGroup `json:"data"`
+}
+
+type RelationEntry struct {
+	Anime     Anime
+	IsCurrent bool
+}
+
+// DisplayTitle prefers English, falls back to Japanese, then standard Title
+func (a Anime) DisplayTitle() string {
+	if a.TitleEnglish != "" {
+		return a.TitleEnglish
+	}
+	if a.TitleJapanese != "" {
+		return a.TitleJapanese
+	}
+	return a.Title
+}