package db

import (
	"context"

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

	"github.com/jacek/pamietnik/backend/internal/domain"
)

type JournalStore struct {
	pool *pgxpool.Pool
}

func NewJournalStore(pool *pgxpool.Pool) *JournalStore {
	return &JournalStore{pool: pool}
}

// InsertEntry creates a new journal entry and returns it with the generated entry_id.
func (s *JournalStore) InsertEntry(ctx context.Context, e domain.JournalEntry) (domain.JournalEntry, error) {
	if e.Visibility == "" {
		e.Visibility = "private"
	}
	if e.Hashtags == nil {
		e.Hashtags = []string{}
	}
	err := s.pool.QueryRow(ctx,
		`INSERT INTO journal_entries (user_id, entry_date, entry_time, title, description, lat, lon, visibility, hashtags)
		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
		 RETURNING entry_id, created_at`,
		e.UserID, e.EntryDate, e.EntryTime, e.Title, e.Description, e.Lat, e.Lon, e.Visibility, e.Hashtags,
	).Scan(&e.EntryID, &e.CreatedAt)
	return e, err
}

// InsertImage attaches an image record to an entry.
func (s *JournalStore) InsertImage(ctx context.Context, img domain.JournalImage) (domain.JournalImage, error) {
	err := s.pool.QueryRow(ctx,
		`INSERT INTO journal_images (entry_id, filename, original_name, mime_type, size_bytes)
		 VALUES ($1, $2, $3, $4, $5)
		 RETURNING image_id, created_at`,
		img.EntryID, img.Filename, img.OriginalName, img.MimeType, img.SizeBytes,
	).Scan(&img.ImageID, &img.CreatedAt)
	return img, err
}

// ListByDate returns all journal entries for a given date (YYYY-MM-DD), including their images.
func (s *JournalStore) ListByDate(ctx context.Context, userID, date string) ([]domain.JournalEntry, error) {
	rows, err := s.pool.Query(ctx,
		`SELECT entry_id, user_id, entry_date::text, entry_time::text, title, description, lat, lon, visibility, hashtags, created_at
		 FROM journal_entries
		 WHERE user_id = $1 AND entry_date = $2
		 ORDER BY entry_time`,
		userID, date,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	entries, err := collectEntries(rows)
	if err != nil {
		return nil, err
	}
	return s.attachImages(ctx, entries)
}

// ListPublic returns public journal entries ordered by created_at DESC, for infinite scroll.
func (s *JournalStore) ListPublic(ctx context.Context, limit, offset int) ([]domain.JournalEntry, error) {
	rows, err := s.pool.Query(ctx,
		`SELECT entry_id, user_id, entry_date::text, entry_time::text, title, description, lat, lon, visibility, hashtags, created_at
		 FROM journal_entries
		 WHERE visibility = 'public'
		 ORDER BY created_at DESC
		 LIMIT $1 OFFSET $2`,
		limit, offset,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	entries, err := collectEntries(rows)
	if err != nil {
		return nil, err
	}
	return s.attachImages(ctx, entries)
}

// ListByUser returns all entries for a user, ordered by entry_date DESC, entry_time DESC.
func (s *JournalStore) ListByUser(ctx context.Context, userID string) ([]domain.JournalEntry, error) {
	rows, err := s.pool.Query(ctx,
		`SELECT entry_id, user_id, entry_date::text, entry_time::text, title, description, lat, lon, visibility, hashtags, created_at
		 FROM journal_entries
		 WHERE user_id = $1
		 ORDER BY entry_date DESC, entry_time DESC`,
		userID,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	entries, err := collectEntries(rows)
	if err != nil {
		return nil, err
	}
	return s.attachImages(ctx, entries)
}

func collectEntries(rows pgx.Rows) ([]domain.JournalEntry, error) {
	var entries []domain.JournalEntry
	for rows.Next() {
		var e domain.JournalEntry
		if err := rows.Scan(
			&e.EntryID, &e.UserID, &e.EntryDate, &e.EntryTime,
			&e.Title, &e.Description, &e.Lat, &e.Lon, &e.Visibility, &e.Hashtags, &e.CreatedAt,
		); err != nil {
			return nil, err
		}
		entries = append(entries, e)
	}
	return entries, rows.Err()
}

// attachImages loads images for the given entries in a single query and populates .Images.
func (s *JournalStore) attachImages(ctx context.Context, entries []domain.JournalEntry) ([]domain.JournalEntry, error) {
	if len(entries) == 0 {
		return entries, nil
	}
	entryIDs := make([]string, len(entries))
	for i, e := range entries {
		entryIDs[i] = e.EntryID
	}
	imgRows, err := s.pool.Query(ctx,
		`SELECT image_id, entry_id, filename, original_name, mime_type, size_bytes, created_at
		 FROM journal_images WHERE entry_id = ANY($1) ORDER BY created_at`,
		entryIDs,
	)
	if err != nil {
		return nil, err
	}
	defer imgRows.Close()

	imgMap := make(map[string][]domain.JournalImage)
	for imgRows.Next() {
		var img domain.JournalImage
		if err := imgRows.Scan(
			&img.ImageID, &img.EntryID, &img.Filename, &img.OriginalName,
			&img.MimeType, &img.SizeBytes, &img.CreatedAt,
		); err != nil {
			return nil, err
		}
		imgMap[img.EntryID] = append(imgMap[img.EntryID], img)
	}
	if err := imgRows.Err(); err != nil {
		return nil, err
	}
	for i, e := range entries {
		entries[i].Images = imgMap[e.EntryID]
	}
	return entries, nil
}