// Package storage defines the unified Store interface and helper types used by
// the server and orchestrator.  Concrete implementations back the interface
// with PocketBase (structured data) and MinIO (binary objects).
package storage

import (
	"context"
	"time"

	"github.com/libnovel/scraper/internal/scraper"
)

// ─── Shared types ─────────────────────────────────────────────────────────────

// ChapterInfo is a lightweight chapter descriptor (mirrors writer.ChapterInfo).
type ChapterInfo struct {
	Number int
	Title  string
	Date   string
}

// RankingItem represents a single entry in the novel ranking list.
// Aliased from scraper.RankingItem for convenience within this package.
type RankingItem = scraper.RankingItem

// ReadingProgress holds a single user's reading position for one book.
type ReadingProgress struct {
	Slug      string    `json:"slug"`
	Chapter   int       `json:"chapter"`
	UpdatedAt time.Time `json:"updated_at"`
}

// AudioJob represents a single audio-generation job record from the
// audio_jobs collection.
type AudioJob struct {
	ID           string    `json:"id"`
	CacheKey     string    `json:"cache_key"` // "slug/chapter/voice"
	Slug         string    `json:"slug"`
	Chapter      int       `json:"chapter"`
	Voice        string    `json:"voice"`
	Status       string    `json:"status"` // "pending" | "generating" | "done" | "failed"
	ErrorMessage string    `json:"error_message,omitempty"`
	Started      time.Time `json:"started"`
	Finished     time.Time `json:"finished,omitempty"`
}

// ScrapeTask represents a single scraping job record from the scraping_tasks
// collection.
type ScrapeTask struct {
	ID              string    `json:"id"`
	Kind            string    `json:"kind"`       // "catalogue" | "book"
	TargetURL       string    `json:"target_url"` // non-empty for single-book scrapes
	Status          string    `json:"status"`     // "running" | "done" | "failed" | "cancelled"
	BooksFound      int       `json:"books_found"`
	ChaptersScraped int       `json:"chapters_scraped"`
	ChaptersSkipped int       `json:"chapters_skipped"`
	Errors          int       `json:"errors"`
	Started         time.Time `json:"started"`
	Finished        time.Time `json:"finished,omitempty"`
	ErrorMessage    string    `json:"error_message,omitempty"`
}

// ScrapeTaskUpdate carries the fields that can be patched on a ScrapeTask.
// Zero-value fields are still sent; callers should only include keys they want
// to change via the map form used inside the store implementation.
type ScrapeTaskUpdate struct {
	Status          string
	BooksFound      int
	ChaptersScraped int
	ChaptersSkipped int
	Errors          int
	Finished        time.Time // zero = not finished yet
	ErrorMessage    string
}

// ─── Store interface ──────────────────────────────────────────────────────────

// Store is the single persistence abstraction consumed by the server and the
// orchestrator.  Implementations may route calls to different backends
// (PocketBase for structured records, MinIO for binary blobs).
type Store interface {
	// ── Book metadata ──────────────────────────────────────────────────────

	// WriteMetadata upserts book metadata.
	WriteMetadata(ctx context.Context, meta scraper.BookMeta) error
	// ReadMetadata returns the metadata for slug. Returns (zero, false, nil)
	// when the book is not found.
	ReadMetadata(ctx context.Context, slug string) (scraper.BookMeta, bool, error)
	// ListBooks returns all books, sorted alphabetically by title.
	ListBooks(ctx context.Context) ([]scraper.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

	// ── Chapters (binary blobs in MinIO) ───────────────────────────────────

	// ChapterExists returns true if the markdown file for the given ref exists.
	ChapterExists(ctx context.Context, slug string, ref scraper.ChapterRef) bool
	// WriteChapter stores the chapter markdown.
	WriteChapter(ctx context.Context, slug string, chapter scraper.Chapter) error
	// WriteChapterRefs persists chapter metadata (number + title) into the
	// chapters_idx table without fetching or storing any chapter text.
	// It is used to pre-populate the chapter list when a book is first seen
	// via a live preview, before its chapter text has been scraped.
	WriteChapterRefs(ctx context.Context, slug string, refs []scraper.ChapterRef) error
	// 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) ([]ChapterInfo, error)
	// CountChapters returns the number of stored chapters for slug.
	CountChapters(ctx context.Context, slug string) int
	// ReindexChapters rebuilds chapters_idx from MinIO objects for slug.
	// Returns the number of chapters indexed.
	ReindexChapters(ctx context.Context, slug string) (int, error)

	// ── Ranking ────────────────────────────────────────────────────────────

	// WriteRankingItem upserts a single ranking entry (keyed on Slug).
	WriteRankingItem(ctx context.Context, item RankingItem) error
	// ReadRankingItems returns all ranking items sorted by rank ascending.
	ReadRankingItems(ctx context.Context) ([]RankingItem, error)
	// RankingFreshEnough returns true when ranking rows exist and the most
	// recent Updated timestamp is within maxAge of now.
	RankingFreshEnough(ctx context.Context, maxAge time.Duration) (bool, error)

	// ── Audio cache ────────────────────────────────────────────────────────

	// GetAudioCache returns the Kokoro filename for cacheKey, or ("", false).
	GetAudioCache(ctx context.Context, cacheKey string) (string, bool)
	// SetAudioCache persists a Kokoro filename for cacheKey.
	SetAudioCache(ctx context.Context, cacheKey, filename string) error
	// PutAudio stores raw audio bytes under the given MinIO object key.
	PutAudio(ctx context.Context, key string, data []byte) error

	// ── Reading progress ───────────────────────────────────────────────────

	// GetProgress returns the reading progress for the given session ID and slug.
	// Returns (zero, false) if no progress is recorded.
	GetProgress(ctx context.Context, sessionID, slug string) (ReadingProgress, bool)
	// SetProgress saves or updates reading progress.
	SetProgress(ctx context.Context, sessionID string, p ReadingProgress) error
	// AllProgress returns all progress entries for a session.
	AllProgress(ctx context.Context, sessionID string) ([]ReadingProgress, error)
	// DeleteProgress removes progress for a specific slug.
	DeleteProgress(ctx context.Context, sessionID, slug string) error

	// ── Audio object paths (MinIO) ─────────────────────────────────────────

	// 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 the bucket.
	AudioExists(ctx context.Context, key string) bool

	// ── Presigned URLs ─────────────────────────────────────────────────────

	// 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 directly to MinIO, and the object key that will be stored.
	// 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, or ("", false, nil) if none.
	PresignAvatarURL(ctx context.Context, userID string) (string, bool, error)

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

	// ── Browse page snapshots (MinIO) ──────────────────────────────────────

	// SaveBrowsePage stores a SingleFile HTML snapshot for the given cache key.
	SaveBrowsePage(ctx context.Context, key, html string) error
	// GetBrowsePage retrieves a cached HTML snapshot. Returns ("", false, nil)
	// when no snapshot exists for the key.
	GetBrowsePage(ctx context.Context, key string) (string, bool, error)
	// BrowseHTMLKey returns the MinIO object key for a SingleFile HTML snapshot.
	// Layout: {domain}/html/page-{n}.html
	BrowseHTMLKey(domain string, page int) string
	// BrowseFilteredHTMLKey returns the MinIO object key for a browse page snapshot
	// that incorporates sort/genre/status so different filter combos are cached separately.
	BrowseFilteredHTMLKey(domain string, page int, sort, genre, status string) string
	// BrowseCoverKey returns the MinIO object key for a cached book cover image.
	// Layout: {domain}/assets/book-covers/{slug}.jpg
	BrowseCoverKey(domain, slug string) string
	// SaveBrowseAsset stores a binary asset (e.g. a cover image) in the browse bucket.
	SaveBrowseAsset(ctx context.Context, key string, data []byte, contentType string) error
	// GetBrowseAsset retrieves a binary asset from the browse bucket.
	// Returns (nil, "", false, nil) when the object does not exist.
	GetBrowseAsset(ctx context.Context, key string) ([]byte, string, bool, error)

	// ── Scraping tasks ─────────────────────────────────────────────────────

	// CreateScrapeTask inserts a new scraping_tasks record with status="running"
	// and returns the assigned ID.
	CreateScrapeTask(ctx context.Context, kind, targetURL string) (string, error)
	// UpdateScrapeTask patches an existing task record.
	UpdateScrapeTask(ctx context.Context, id string, u ScrapeTaskUpdate) error
	// ListScrapeTasks returns all tasks sorted by started descending.
	ListScrapeTasks(ctx context.Context) ([]ScrapeTask, error)

	// ── Audio jobs ─────────────────────────────────────────────────────────

	// CreateAudioJob inserts a new audio_jobs record with status="pending"
	// and returns the assigned ID.
	CreateAudioJob(ctx context.Context, slug string, chapter int, voice string) (string, error)
	// UpdateAudioJob patches an existing audio job record (status, error, finished).
	UpdateAudioJob(ctx context.Context, id, status, errMsg string, finished time.Time) error
	// GetAudioJob returns the most recent audio job for the given cache key,
	// or (zero, false, nil) if none exists.
	GetAudioJob(ctx context.Context, cacheKey string) (AudioJob, bool, error)
	// ListAudioJobs returns all audio jobs sorted by started descending.
	ListAudioJobs(ctx context.Context) ([]AudioJob, error)
}