// Package neofs provides a NeoFS storage adapter for Tutus.
//
// NeoFS is a decentralized storage network that can be deployed as either
// a public network or a private sovereign network for government use.
//
// For sovereign deployments, governments should run their own NeoFS
// infrastructure within national borders to ensure data residency compliance.
package neofs

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"time"

	"github.com/nspcc-dev/neofs-sdk-go/pool"

	"github.com/tutus-one/tutus-chain/pkg/storage"
)

const providerName = "neofs"

// Adapter implements the storage.Provider interface for NeoFS.
type Adapter struct {
	pool      *pool.Pool
	container string
	timeout   time.Duration
}

// Config holds NeoFS adapter configuration.
type Config struct {
	// Pool is an initialized NeoFS connection pool
	Pool *pool.Pool
	// Container is the NeoFS container ID string
	Container string
	// Timeout for NeoFS operations
	Timeout time.Duration
}

// New creates a new NeoFS storage adapter.
func New(cfg Config) *Adapter {
	timeout := cfg.Timeout
	if timeout == 0 {
		timeout = 30 * time.Second
	}
	return &Adapter{
		pool:      cfg.Pool,
		container: cfg.Container,
		timeout:   timeout,
	}
}

// Name returns the provider identifier.
func (a *Adapter) Name() string {
	return providerName
}

// Put stores data in NeoFS and returns the object ID.
func (a *Adapter) Put(ctx context.Context, data io.Reader, opts storage.PutOptions) (storage.ObjectID, error) {
	ctx, cancel := context.WithTimeout(ctx, a.timeout)
	defer cancel()

	// Read all data
	content, err := io.ReadAll(data)
	if err != nil {
		return storage.ObjectID{}, fmt.Errorf("neofs: read data: %w", err)
	}

	// TODO: Implement NeoFS object upload using pool
	// This requires proper NeoFS SDK integration with:
	// - Container ID parsing
	// - Object creation with attributes
	// - Signing with user credentials
	// - Upload via pool.ObjectPutInit()

	_ = content // Use content when implementing

	return storage.ObjectID{}, fmt.Errorf("neofs: Put not yet implemented - use existing neofs helpers")
}

// Get retrieves an object from NeoFS.
func (a *Adapter) Get(ctx context.Context, id storage.ObjectID) (io.ReadCloser, error) {
	ctx, cancel := context.WithTimeout(ctx, a.timeout)
	defer cancel()

	// TODO: Implement NeoFS object download
	// This requires:
	// - Object ID parsing
	// - Download via pool.ObjectGetInit()
	// - Payload reading

	_ = ctx // Use ctx when implementing

	return nil, fmt.Errorf("neofs: Get not yet implemented - use existing neofs helpers")
}

// Delete removes an object from NeoFS.
func (a *Adapter) Delete(ctx context.Context, id storage.ObjectID) error {
	ctx, cancel := context.WithTimeout(ctx, a.timeout)
	defer cancel()

	// TODO: Implement NeoFS object deletion
	_ = ctx

	return fmt.Errorf("neofs: Delete not yet implemented")
}

// Exists checks if an object exists in NeoFS.
func (a *Adapter) Exists(ctx context.Context, id storage.ObjectID) (bool, error) {
	ctx, cancel := context.WithTimeout(ctx, a.timeout)
	defer cancel()

	// TODO: Implement via ObjectHead
	_ = ctx

	return false, fmt.Errorf("neofs: Exists not yet implemented")
}

// List returns objects matching the given prefix.
func (a *Adapter) List(ctx context.Context, prefix string, opts storage.ListOptions) ([]storage.ObjectInfo, error) {
	ctx, cancel := context.WithTimeout(ctx, a.timeout)
	defer cancel()

	// TODO: Implement via ObjectSearch
	_ = ctx
	_ = prefix

	return nil, fmt.Errorf("neofs: List not yet implemented")
}

// Head retrieves object metadata.
func (a *Adapter) Head(ctx context.Context, id storage.ObjectID) (storage.ObjectInfo, error) {
	ctx, cancel := context.WithTimeout(ctx, a.timeout)
	defer cancel()

	// TODO: Implement via ObjectHead
	_ = ctx

	return storage.ObjectInfo{}, fmt.Errorf("neofs: Head not yet implemented")
}

// Close releases NeoFS pool resources.
func (a *Adapter) Close() error {
	if a.pool != nil {
		a.pool.Close()
	}
	return nil
}

// WrapExistingReader wraps data from the existing NeoFS helpers into the storage interface.
// This is a bridge to use existing pkg/services/helpers/neofs code with the new interface.
func WrapExistingReader(data []byte) io.ReadCloser {
	return io.NopCloser(bytes.NewReader(data))
}