gitdiff

type FileChange struct {
	Path     string
	OrigPath string
	Status   Status
	Staged   bool
}

type FilePatch struct {
	Preamble string
	Hunks    []Hunk
}

type Hunk struct {
	Header string
	Lines  []string
}

type ReadSource interface {
	Changes() (staged, unstaged []FileChange, err error)
	Diff(fc FileChange) (oldContent, newContent string, isBinary bool, err error)
	Workdir() string
}

type Source interface {
	// Changes returns the staged and unstaged file groups.
	Changes() (staged, unstaged []FileChange, err error)
	// Diff returns the before/after content for a change. Refs are chosen by
	// group: a staged entry compares HEAD→index, an unstaged entry compares
	// index(→HEAD fallback)→working tree. Added/untracked → old "", deleted →
	// new "". isBinary is true for binary or oversized content (skip diffing).
	Diff(fc FileChange) (oldContent, newContent string, isBinary bool, err error)
	// Stage runs `git add` on the path.
	Stage(path string) error
	// Unstage removes the path from the index.
	Unstage(path string) error
	// StageAll stages every working-tree change (`git add -A`): modifications,
	// additions, deletions, and untracked files.
	StageAll() error
	// UnstageAll removes all paths from the index (`git reset -q HEAD`), leaving
	// the working tree untouched.
	UnstageAll() error
	// Discard reverts a working-tree change: it restores a tracked file from the
	// index (HEAD when nothing is staged) and deletes an untracked file. This is
	// destructive - the discarded working-tree changes cannot be recovered.
	Discard(fc FileChange) error
	// WorktreePatch returns the unstaged (index→working tree) patch for a path,
	// for hunk-level staging.
	WorktreePatch(path string) (FilePatch, error)
	// IndexPatch returns the staged (HEAD→index) patch for a path, for
	// hunk-level unstaging.
	IndexPatch(path string) (FilePatch, error)
	// ApplyHunk applies a single hunk to the index. reverse=false stages a
	// worktree hunk; reverse=true unstages a staged hunk.
	ApplyHunk(fp FilePatch, hunkIndex int, reverse bool) error
	// ApplyLines applies only the selected change-lines of one hunk to the index.
	// selected holds 0-based indices into the hunk's Lines slice ('+'/'-' lines
	// only; others are ignored). reverse=false stages the selected worktree lines,
	// reverse=true unstages the selected staged lines. Unselected changes are
	// neutralized so they keep their prior staged/unstaged state.
	ApplyLines(fp FilePatch, hunkIndex int, selected map[int]bool, reverse bool) error
	// Workdir returns the repository working directory that change paths are
	// relative to, for resolving an absolute path (e.g. to open in an editor).
	Workdir() string
}

type Status rune