sync

type BisyncOptions struct {
	// ConflictStrategy determines how to handle files changed on both sides.
	// Default is ConflictNewerWins.
	ConflictStrategy ConflictStrategy

	// ConflictSuffix is appended to filenames when using ConflictKeepBoth.
	// Default is ".conflict".
	ConflictSuffix string

	// DryRun reports what would be done without making changes.
	DryRun bool

	// Checksum uses file checksums for comparison instead of size/time.
	Checksum bool

	// DeleteMissing deletes files that don't exist on the other side.
	// Use with caution - this can result in data loss if a file was
	// intentionally deleted on one side but still exists on the other.
	DeleteMissing bool

	// Progress is called with progress updates during sync.
	Progress func(Progress)

	// MaxErrors is the maximum number of errors before aborting.
	MaxErrors int

	// Concurrency is the number of concurrent file transfers.
	// Default is 4.
	Concurrency int

	// Filter specifies which files to include/exclude.
	Filter *filter.Filter

	// BandwidthLimit is the maximum bytes per second for transfers.
	BandwidthLimit int64

	// Retry configures retry behavior for failed operations.
	Retry *RetryConfig

	// PreserveMetadata controls which metadata to preserve.
	PreserveMetadata *MetadataOptions

	// Logger for structured logging. If nil, no logging is performed.
	Logger *slog.Logger
}

type BisyncResult struct {
	// CopiedToPath2 is files copied from path1 to path2.
	CopiedToPath2 int

	// CopiedToPath1 is files copied from path2 to path1.
	CopiedToPath1 int

	// UpdatedInPath2 is files updated in path2 from path1.
	UpdatedInPath2 int

	// UpdatedInPath1 is files updated in path1 from path2.
	UpdatedInPath1 int

	// DeletedFromPath1 is files deleted from path1.
	DeletedFromPath1 int

	// DeletedFromPath2 is files deleted from path2.
	DeletedFromPath2 int

	// Conflicts is the list of conflicting files.
	Conflicts []Conflict

	// Skipped is the number of files skipped (already in sync).
	Skipped int

	// Errors contains any errors that occurred.
	Errors []FileError

	// BytesTransferred is the total bytes transferred.
	BytesTransferred int64

	// Duration is how long the sync took.
	Duration time.Duration

	// DryRun indicates if this was a dry run.
	DryRun bool
}

type CheckResult struct {
	// Match lists files that match between source and destination.
	Match []string

	// Differ lists files that exist in both but have different content.
	Differ []string

	// SrcOnly lists files that exist only in source.
	SrcOnly []string

	// DstOnly lists files that exist only in destination.
	DstOnly []string

	// Errors contains any errors that occurred during checking.
	Errors []FileError
}

type Conflict struct {
	// Path is the relative path of the conflicting file.
	Path string

	// Path1Info is the file info from path1.
	Path1Info FileInfo

	// Path2Info is the file info from path2.
	Path2Info FileInfo

	// Resolution describes how the conflict was resolved.
	Resolution string

	// Error is set if the conflict could not be resolved.
	Error error
}

type ConflictStrategy int

type DiffEntry struct {
	Path   string
	Status DiffStatus
}

type DiffStatus string

type FileError struct {
	Path string
	Op   string // "copy", "delete", "stat", etc.
	Err  error
}

type FileInfo struct {
	Path    string
	Size    int64
	ModTime time.Time
	Hash    string // MD5 or other hash if available
	IsDir   bool
}

type MetadataOptions struct {
	// ContentType preserves the MIME content type.
	// Default is true (always preserved).
	ContentType bool

	// ModTime preserves the modification time.
	// Requires backend support (Features().SetModTime).
	ModTime bool

	// CustomMetadata preserves backend-specific custom metadata.
	// For S3, this includes user-defined metadata headers.
	CustomMetadata bool
}

type Options struct {
	// DeleteExtra deletes files in destination that don't exist in source.
	// When false, behaves like CopyDir (only adds/updates, never deletes).
	DeleteExtra bool

	// DryRun reports what would be done without making changes.
	DryRun bool

	// Checksum uses file checksums (when available) for comparison
	// instead of just size and modification time.
	// This is slower but more accurate.
	Checksum bool

	// IgnoreExisting skips files that already exist in destination.
	// Useful for resuming interrupted syncs.
	IgnoreExisting bool

	// IgnoreSize ignores size when comparing files.
	// Only compares modification time (or checksum if Checksum is true).
	IgnoreSize bool

	// IgnoreTime ignores modification time when comparing files.
	// Only compares size (or checksum if Checksum is true).
	IgnoreTime bool

	// SizeOnly compares files by size only, ignoring modification time.
	SizeOnly bool

	// Progress is called with progress updates during sync.
	// Can be nil if progress updates aren't needed.
	Progress func(Progress)

	// MaxErrors is the maximum number of errors before aborting.
	// 0 means abort on first error.
	MaxErrors int

	// Concurrency is the number of concurrent file transfers.
	// Default is 4.
	Concurrency int

	// Filter specifies which files to include/exclude from sync.
	// If nil, all files are included.
	Filter *filter.Filter

	// DeleteExcluded deletes files from destination that match exclude filters.
	// Only applies when DeleteExtra is true.
	DeleteExcluded bool

	// BandwidthLimit is the maximum bytes per second for transfers.
	// 0 means unlimited. The limit is shared across all concurrent transfers.
	// Example: 1048576 for 1MB/s, or use filter.MB constant.
	BandwidthLimit int64

	// Retry configures retry behavior for failed file operations.
	// If nil or MaxRetries is 0, operations are not retried.
	Retry *RetryConfig

	// PreserveMetadata controls which metadata to preserve during sync.
	// If nil, only content-type is preserved (default behavior).
	PreserveMetadata *MetadataOptions

	// Logger is used for structured logging during sync operations.
	// If nil, a null logger is used (no logging).
	Logger *slog.Logger
}

type Phase string

type Progress struct {
	// Phase indicates the current sync phase.
	Phase Phase

	// CurrentFile is the file currently being processed.
	CurrentFile string

	// BytesTransferred is the number of bytes transferred so far.
	BytesTransferred int64

	// TotalBytes is the total bytes to transfer (if known).
	TotalBytes int64

	// FilesTransferred is the number of files transferred so far.
	FilesTransferred int

	// TotalFiles is the total number of files to transfer.
	TotalFiles int

	// FilesDeleted is the number of files deleted so far.
	FilesDeleted int

	// Errors is the number of errors encountered so far.
	Errors int
}

type Result struct {
	// Copied is the number of files copied.
	Copied int

	// Updated is the number of files updated (overwritten).
	Updated int

	// Deleted is the number of files deleted from destination.
	Deleted int

	// Skipped is the number of files skipped (already in sync).
	Skipped int

	// Errors contains any errors that occurred.
	Errors []FileError

	// BytesTransferred is the total bytes transferred.
	BytesTransferred int64

	// Duration is how long the sync took.
	Duration time.Duration

	// DryRun indicates if this was a dry run.
	DryRun bool
}

type RetryConfig struct {
	// MaxRetries is the maximum number of retry attempts.
	// 0 means no retries (fail on first error).
	MaxRetries int

	// InitialDelay is the delay before the first retry.
	// Default is 1 second.
	InitialDelay time.Duration

	// MaxDelay is the maximum delay between retries.
	// Default is 30 seconds.
	MaxDelay time.Duration

	// Multiplier is the factor by which delay increases after each retry.
	// Default is 2.0 (exponential backoff).
	Multiplier float64

	// Jitter adds randomness to delays to prevent thundering herd.
	// 0.1 means +/- 10% random variation. Default is 0.1.
	Jitter float64

	// RetryableErrors is a function that determines if an error should be retried.
	// If nil, all errors are retried.
	RetryableErrors func(error) bool
}

type RetryError struct {
	Attempts int
	LastErr  error
}

type VerifyResult struct {
	// Verified is true if all files match.
	Verified bool

	// TotalFiles is the total number of files checked.
	TotalFiles int

	// MatchingFiles is the number of files that match.
	MatchingFiles int

	// MismatchedFiles lists files that don't match.
	MismatchedFiles []string

	// MissingInDst lists files missing from destination.
	MissingInDst []string

	// ExtraInDst lists files in destination but not in source.
	ExtraInDst []string

	// Errors contains any errors encountered during verification.
	Errors []FileError
}