package database

import (
	"context"
	"database/sql"
	"fmt"

	"git.eeqj.de/sneak/vaultik/internal/log"
)

type ChunkRepository struct {
	db *DB
}

func NewChunkRepository(db *DB) *ChunkRepository {
	return &ChunkRepository{db: db}
}

func (r *ChunkRepository) Create(ctx context.Context, tx *sql.Tx, chunk *Chunk) error {
	query := `
		INSERT INTO chunks (chunk_hash, sha256, size)
		VALUES (?, ?, ?)
		ON CONFLICT(chunk_hash) DO NOTHING
	`

	var err error
	if tx != nil {
		_, err = tx.ExecContext(ctx, query, chunk.ChunkHash, chunk.SHA256, chunk.Size)
	} else {
		_, err = r.db.ExecWithLog(ctx, query, chunk.ChunkHash, chunk.SHA256, chunk.Size)
	}

	if err != nil {
		return fmt.Errorf("inserting chunk: %w", err)
	}

	return nil
}

func (r *ChunkRepository) GetByHash(ctx context.Context, hash string) (*Chunk, error) {
	query := `
		SELECT chunk_hash, sha256, size
		FROM chunks
		WHERE chunk_hash = ?
	`

	var chunk Chunk

	err := r.db.conn.QueryRowContext(ctx, query, hash).Scan(
		&chunk.ChunkHash,
		&chunk.SHA256,
		&chunk.Size,
	)

	if err == sql.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, fmt.Errorf("querying chunk: %w", err)
	}

	return &chunk, nil
}

func (r *ChunkRepository) GetByHashes(ctx context.Context, hashes []string) ([]*Chunk, error) {
	if len(hashes) == 0 {
		return nil, nil
	}

	query := `
		SELECT chunk_hash, sha256, size
		FROM chunks
		WHERE chunk_hash IN (`

	args := make([]interface{}, len(hashes))
	for i, hash := range hashes {
		if i > 0 {
			query += ", "
		}
		query += "?"
		args[i] = hash
	}
	query += ") ORDER BY chunk_hash"

	rows, err := r.db.conn.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("querying chunks: %w", err)
	}
	defer CloseRows(rows)

	var chunks []*Chunk
	for rows.Next() {
		var chunk Chunk

		err := rows.Scan(
			&chunk.ChunkHash,
			&chunk.SHA256,
			&chunk.Size,
		)
		if err != nil {
			return nil, fmt.Errorf("scanning chunk: %w", err)
		}

		chunks = append(chunks, &chunk)
	}

	return chunks, rows.Err()
}

func (r *ChunkRepository) ListUnpacked(ctx context.Context, limit int) ([]*Chunk, error) {
	query := `
		SELECT c.chunk_hash, c.sha256, c.size
		FROM chunks c
		LEFT JOIN blob_chunks bc ON c.chunk_hash = bc.chunk_hash
		WHERE bc.chunk_hash IS NULL
		ORDER BY c.chunk_hash
		LIMIT ?
	`

	rows, err := r.db.conn.QueryContext(ctx, query, limit)
	if err != nil {
		return nil, fmt.Errorf("querying unpacked chunks: %w", err)
	}
	defer CloseRows(rows)

	var chunks []*Chunk
	for rows.Next() {
		var chunk Chunk

		err := rows.Scan(
			&chunk.ChunkHash,
			&chunk.SHA256,
			&chunk.Size,
		)
		if err != nil {
			return nil, fmt.Errorf("scanning chunk: %w", err)
		}

		chunks = append(chunks, &chunk)
	}

	return chunks, rows.Err()
}

// DeleteOrphaned deletes chunks that are not referenced by any file
func (r *ChunkRepository) DeleteOrphaned(ctx context.Context) error {
	query := `
		DELETE FROM chunks 
		WHERE NOT EXISTS (
			SELECT 1 FROM file_chunks 
			WHERE file_chunks.chunk_hash = chunks.chunk_hash
		)
	`

	result, err := r.db.ExecWithLog(ctx, query)
	if err != nil {
		return fmt.Errorf("deleting orphaned chunks: %w", err)
	}

	rowsAffected, _ := result.RowsAffected()
	if rowsAffected > 0 {
		log.Debug("Deleted orphaned chunks", "count", rowsAffected)
	}

	return nil
}