package vcs

import (
	"context"
	"errors"
	"io"

	"tangled.org/core/knotserver/git"
	"tangled.org/core/knotserver/pijul"
)

// ErrBinaryFile is returned by FileContentN when the file appears to be binary.
// It matches both git.ErrBinaryFile and pijul.ErrBinaryFile.
var ErrBinaryFile = errors.New("binary file")

// IsBinaryFileError returns true if the error indicates a binary file,
// matching against both the vcs, git, and pijul error types.
func IsBinaryFileError(err error) bool {
	return errors.Is(err, ErrBinaryFile) ||
		errors.Is(err, git.ErrBinaryFile) ||
		errors.Is(err, pijul.ErrBinaryFile)
}

// ReadRepo provides read-only access to a VCS repository, abstracting
// over git and pijul.
type ReadRepo interface {
	// VCSType returns "git" or "pijul".
	VCSType() string

	// Path returns the on-disk path of the repository.
	Path() string

	// History returns history entries (commits/changes) with pagination.
	History(offset, limit int) ([]HistoryEntry, error)

	// TotalHistoryEntries returns the total count of commits/changes.
	TotalHistoryEntries() (int, error)

	// HistoryEntry returns a single commit/change by hash.
	HistoryEntry(hash string) (*HistoryEntry, error)

	// Branches returns branches/channels with optional pagination.
	Branches(opts *PaginationOpts) ([]BranchInfo, error)

	// DefaultBranch returns the name of the default branch/channel.
	DefaultBranch() (string, error)

	// FileTree returns the directory listing at the given path.
	FileTree(ctx context.Context, path string) ([]TreeEntry, error)

	// FileContentN reads up to cap bytes of a file, returning ErrBinaryFile
	// if the file appears to be binary.
	FileContentN(path string, cap int64) ([]byte, error)

	// RawContent reads the full raw content of a file.
	RawContent(path string) ([]byte, error)

	// WriteTar writes a tar archive of the repository to w, prefixing
	// all paths with prefix.
	WriteTar(w io.Writer, prefix string) error

	// Tags returns tags with optional pagination. Pijul repos return nil.
	Tags(opts *PaginationOpts) ([]TagInfo, error)
}

// MutableRepo extends ReadRepo with write operations.
type MutableRepo interface {
	ReadRepo

	// SetDefaultBranch sets the default branch/channel.
	SetDefaultBranch(name string) error

	// DeleteBranch deletes a branch/channel.
	DeleteBranch(name string) error
}