package database

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

// Repositories provides access to all database repositories.
// It serves as a centralized access point for all database operations
// and manages transaction coordination across repositories.
type Repositories struct {
	db         *DB
	Files      *FileRepository
	Chunks     *ChunkRepository
	Blobs      *BlobRepository
	FileChunks *FileChunkRepository
	BlobChunks *BlobChunkRepository
	ChunkFiles *ChunkFileRepository
	Snapshots  *SnapshotRepository
	Uploads    *UploadRepository
}

// NewRepositories creates a new Repositories instance with all repository types.
// Each repository shares the same database connection for coordinated transactions.
func NewRepositories(db *DB) *Repositories {
	return &Repositories{
		db:         db,
		Files:      NewFileRepository(db),
		Chunks:     NewChunkRepository(db),
		Blobs:      NewBlobRepository(db),
		FileChunks: NewFileChunkRepository(db),
		BlobChunks: NewBlobChunkRepository(db),
		ChunkFiles: NewChunkFileRepository(db),
		Snapshots:  NewSnapshotRepository(db),
		Uploads:    NewUploadRepository(db.conn),
	}
}

// TxFunc is a function that executes within a database transaction.
// The transaction is automatically committed if the function returns nil,
// or rolled back if it returns an error.
type TxFunc func(ctx context.Context, tx *sql.Tx) error

// WithTx executes a function within a write transaction.
// SQLite handles its own locking internally, so no explicit locking is needed.
// The transaction is automatically committed on success or rolled back on error.
// This method should be used for all write operations to ensure atomicity.
func (r *Repositories) WithTx(ctx context.Context, fn TxFunc) error {
	LogSQL("WithTx", "Beginning transaction", "")
	tx, err := r.db.BeginTx(ctx, nil)
	if err != nil {
		return fmt.Errorf("beginning transaction: %w", err)
	}
	LogSQL("WithTx", "Transaction started", "")

	defer func() {
		if p := recover(); p != nil {
			if rollbackErr := tx.Rollback(); rollbackErr != nil {
				Fatal("failed to rollback transaction: %v", rollbackErr)
			}
			panic(p)
		} else if err != nil {
			if rollbackErr := tx.Rollback(); rollbackErr != nil {
				Fatal("failed to rollback transaction: %v", rollbackErr)
			}
		}
	}()

	err = fn(ctx, tx)
	if err != nil {
		return err
	}

	return tx.Commit()
}

// WithReadTx executes a function within a read-only transaction.
// Read transactions can run concurrently with other read transactions
// but will be blocked by write transactions. The transaction is
// automatically committed on success or rolled back on error.
func (r *Repositories) WithReadTx(ctx context.Context, fn TxFunc) error {
	opts := &sql.TxOptions{
		ReadOnly: true,
	}
	tx, err := r.db.BeginTx(ctx, opts)
	if err != nil {
		return fmt.Errorf("beginning read transaction: %w", err)
	}

	defer func() {
		if p := recover(); p != nil {
			if rollbackErr := tx.Rollback(); rollbackErr != nil {
				Fatal("failed to rollback transaction: %v", rollbackErr)
			}
			panic(p)
		} else if err != nil {
			if rollbackErr := tx.Rollback(); rollbackErr != nil {
				Fatal("failed to rollback transaction: %v", rollbackErr)
			}
		}
	}()

	err = fn(ctx, tx)
	if err != nil {
		return err
	}

	return tx.Commit()
}