backend

type Backend interface {
	// Name returns the canonical backend identifier, e.g. "git" or "jj".
	Name() string

	// Priority returns the detection priority. Higher values are checked first.
	// For colocated repos, the backend with the highest priority wins.
	Priority() int

	// Detect returns true if the directory at path is managed by this VCS.
	// It must not return an error for non-matching dirs; only real I/O
	// failures warrant an error.
	Detect(path string) (bool, error)

	// Status returns the unified status for the repo at path.
	Status(ctx context.Context, path string) (RepoStatus, error)

	// SubcommandArgs returns the full argument list for a VCS operation.
	// For example, git returns ["fetch"] but jj returns ["git", "fetch"]
	// because jj wraps git operations under the "git" subcommand.
	SubcommandArgs(op string) []string

	// Subcommands returns available subcommands for the VCS tool, e.g.
	// ["add", "branch", "log", "status"] for git. Returns an empty slice
	// when subcommands cannot be loaded (tool not found, parse error, etc).
	Subcommands(ctx context.Context) ([]string, error)

	// Run executes the given args using this VCS tool in path.
	// When interactive is true, the caller has already arranged for the
	// subprocess to inherit the terminal; Run must not capture output.
	Run(ctx context.Context, path string, args []string, interactive bool) (RunResult, error)
}

type BookmarkStatus struct {
	Name string

	// Remote name (e.g. "origin"). Empty when no remote.
	Remote string

	Ahead  int
	Behind int

	// True when jj reports a bookmark conflict (diverged push).
	// For git this is always false; git represents this as a diverged state.
	Conflict bool

	// Computed sync state derived from Ahead/Behind/Remote.
	State RefState
}

type RefState int

type RepoStatus struct {
	// Ref is the human-readable current position: branch name for git,
	// change ID short for jj.
	Ref string

	// Bookmarks holds tracking state for all local bookmarks/branches.
	// Git populates exactly one entry (the current branch).
	// jj populates one entry per local bookmark at or near @.
	Bookmarks []BookmarkStatus

	// OverallState is the worst-case RefState across all Bookmarks,
	// used for sorting and the summary colour in the ll table.
	OverallState RefState

	Dirty bool

	// True when the repo has unresolved VCS conflicts
	// (jj conflict markers, git merge conflicts).
	Conflict bool

	CommitMsg string

	// Relative commit time (e.g. "3 days ago").
	CommitTime string

	// Working copy (@) commits ahead of HEAD bookmark. Only populated by
	// the jj backend (git's working copy is always at the branch tip).
	LocalAhead int
}

type RunResult struct {
	// Output is the combined stdout+stderr of the subprocess, captured
	// when running in parallel. In interactive mode this is empty.
	Output   string
	ExitCode int
}