// Package bookstore defines the segregated read/write interfaces for book,
// chapter, ranking, progress, audio, and presign data.
//
// Interface segregation:
//   - BookWriter   — used by the runner to persist scraped data.
//   - BookReader   — used by the backend to serve book/chapter data.
//   - RankingStore — used by both runner (write) and backend (read).
//   - PresignStore — used only by the backend for URL signing.
//   - AudioStore   — used by the runner to store audio; backend for presign.
//   - ProgressStore— used only by the backend for reading progress.
//
// Concrete implementations live in internal/storage.
package bookstore

import (
	"context"
	"time"

	"github.com/libnovel/backend/internal/domain"
)

// BookWriter is the write side used by the runner after scraping a book.
type BookWriter interface {
	// WriteMetadata upserts all bibliographic fields for a book.
	WriteMetadata(ctx context.Context, meta domain.BookMeta) error

	// WriteChapter stores a fully-scraped chapter's text in MinIO and
	// updates the chapters_idx record in PocketBase.
	WriteChapter(ctx context.Context, slug string, chapter domain.Chapter) error

	// WriteChapterRefs persists chapter metadata (number + title) into
	// chapters_idx without fetching or storing chapter text.
	WriteChapterRefs(ctx context.Context, slug string, refs []domain.ChapterRef) error

	// ChapterExists returns true if the markdown object for ref already exists.
	ChapterExists(ctx context.Context, slug string, ref domain.ChapterRef) bool
}

// BookReader is the read side used by the backend to serve content.
type BookReader interface {
	// ReadMetadata returns the metadata for slug.
	// Returns (zero, false, nil) when not found.
	ReadMetadata(ctx context.Context, slug string) (domain.BookMeta, bool, error)

	// ListBooks returns all books sorted alphabetically by title.
	ListBooks(ctx context.Context) ([]domain.BookMeta, error)

	// LocalSlugs returns the set of slugs that have metadata stored.
	LocalSlugs(ctx context.Context) (map[string]bool, error)

	// MetadataMtime returns the Unix-second mtime of the metadata record, or 0.
	MetadataMtime(ctx context.Context, slug string) int64

	// ReadChapter returns the raw markdown for chapter number n.
	ReadChapter(ctx context.Context, slug string, n int) (string, error)

	// ListChapters returns all stored chapters for slug, sorted by number.
	ListChapters(ctx context.Context, slug string) ([]domain.ChapterInfo, error)

	// CountChapters returns the count of stored chapters.
	CountChapters(ctx context.Context, slug string) int

	// ReindexChapters rebuilds chapters_idx from MinIO objects for slug.
	ReindexChapters(ctx context.Context, slug string) (int, error)
}

// RankingStore covers ranking reads and writes.
type RankingStore interface {
	// WriteRankingItem upserts a single ranking entry (keyed on Slug).
	WriteRankingItem(ctx context.Context, item domain.RankingItem) error

	// ReadRankingItems returns all ranking items sorted by rank ascending.
	ReadRankingItems(ctx context.Context) ([]domain.RankingItem, error)

	// RankingFreshEnough returns true when ranking rows exist and the most
	// recent Updated timestamp is within maxAge.
	RankingFreshEnough(ctx context.Context, maxAge time.Duration) (bool, error)
}

// AudioStore covers audio object storage (runner writes; backend reads).
type AudioStore interface {
	// AudioObjectKey returns the MinIO object key for a cached audio file.
	AudioObjectKey(slug string, n int, voice string) string

	// AudioExists returns true when the audio object is present in MinIO.
	AudioExists(ctx context.Context, key string) bool

	// PutAudio stores raw audio bytes under the given MinIO object key.
	PutAudio(ctx context.Context, key string, data []byte) error
}

// PresignStore generates short-lived URLs — used exclusively by the backend.
type PresignStore interface {
	// PresignChapter returns a presigned GET URL for a chapter markdown object.
	PresignChapter(ctx context.Context, slug string, n int, expires time.Duration) (string, error)

	// PresignAudio returns a presigned GET URL for an audio object.
	PresignAudio(ctx context.Context, key string, expires time.Duration) (string, error)

	// PresignAvatarUpload returns a short-lived presigned PUT URL for uploading
	// an avatar image. ext should be "jpg", "png", or "webp".
	PresignAvatarUpload(ctx context.Context, userID, ext string) (uploadURL, key string, err error)

	// PresignAvatarURL returns a presigned GET URL for a user's avatar.
	// Returns ("", false, nil) when no avatar exists.
	PresignAvatarURL(ctx context.Context, userID string) (string, bool, error)

	// DeleteAvatar removes all avatar objects for a user.
	DeleteAvatar(ctx context.Context, userID string) error
}

// ProgressStore covers per-session reading progress — backend only.
type ProgressStore interface {
	// GetProgress returns the reading progress for the given session + slug.
	GetProgress(ctx context.Context, sessionID, slug string) (domain.ReadingProgress, bool)

	// SetProgress saves or updates reading progress.
	SetProgress(ctx context.Context, sessionID string, p domain.ReadingProgress) error

	// AllProgress returns all progress entries for a session.
	AllProgress(ctx context.Context, sessionID string) ([]domain.ReadingProgress, error)

	// DeleteProgress removes progress for a specific slug.
	DeleteProgress(ctx context.Context, sessionID, slug string) error
}

// BrowseStore covers browse page snapshot storage.
// The runner writes snapshots; the backend reads them.
type BrowseStore interface {
	// PutBrowsePage stores a raw JSON snapshot for a browse page.
	// genre, sort, status, novelType and page identify the page.
	PutBrowsePage(ctx context.Context, genre, sort, status, novelType string, page int, data []byte) error

	// GetBrowsePage retrieves a raw JSON snapshot. Returns (nil, false, nil)
	// when no snapshot exists for the given parameters.
	GetBrowsePage(ctx context.Context, genre, sort, status, novelType string, page int) ([]byte, bool, error)
}