1 files changed, 126 insertions, 0 deletions
diff --git a/internal/resource/dir/source.go b/internal/resource/dir/source.go
new file mode 100644
index 0000000..8f9b73a
--- /dev/null
+++ b/internal/resource/dir/source.go
@@ -0,0 +1,126 @@
+package dir
+
+import (
+	"fmt"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+
+	"codeberg.org/snonux/gonf/internal/resource/file"
+	"codeberg.org/snonux/gonf/internal/resource/link"
+)
+
+// copySourceTree mirrors d.source into d.path, dispatching each entry by
+// kind. Symlink-ness is checked before the dir/file branches: fs.DirEntry
+// reports a symlink's own type via Lstat semantics (never following it), so
+// a symlink in the source tree is recreated as a symlink rather than read as
+// file content.
+func copySourceTree(d *Dir) error {
+	log.Printf("installing files from source %s to %s", d.source, d.path)
+
+	return filepath.WalkDir(d.source, func(path string, entry fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+
+		rel, err := filepath.Rel(d.source, path)
+		if err != nil {
+			return err
+		}
+		if rel == "." {
+			return nil
+		}
+
+		target := filepath.Join(d.path, rel)
+
+		switch {
+		case entry.Type()&fs.ModeSymlink != 0:
+			return copySourceSymlink(path, target)
+		case entry.IsDir():
+			return copySourceDir(d, target)
+		default:
+			return copySourceFile(d, path, target)
+		}
+	})
+}
+
+func copySourceDir(d *Dir, target string) error {
+	if err := os.MkdirAll(target, d.mode); err != nil {
+		return fmt.Errorf("failed to create directory %s: %w", target, err)
+	}
+	return applyAttributesTo(target, d.mode, d.user, d.group)
+}
+
+// copySourceSymlink recreates the symlink found at sourcePath as a symlink
+// at target, preserving its raw (unresolved) link target string. This is
+// correct as long as the destination tree mirrors the source tree 1:1; an
+// absolute link target pointing back into the source tree itself is not
+// remapped into the destination — a pre-existing conceptual limitation of
+// copying a tree of symlinks.
+func copySourceSymlink(sourcePath, target string) error {
+	rawTarget, err := os.Readlink(sourcePath)
+	if err != nil {
+		return fmt.Errorf("failed to read symlink %s: %w", sourcePath, err)
+	}
+	return link.Ensure(target, link.IsSymlink(rawTarget))
+}
+
+// copySourceFile delegates writing a single copied file to the file
+// package's own primitive, using d's file-mode default (not d's directory
+// mode) and passing the mechanically-derived target path verbatim — file's
+// own resolve() strips a ".tmpl" suffix and computes .Param consistently, so
+// dir needs no special-casing of its own.
+func copySourceFile(d *Dir, sourcePath, target string) error {
+	return file.Ensure(target,
+		file.WithSource(sourcePath),
+		file.WithMode(d.fileMode),
+		file.WithUser(d.user),
+		file.WithGroup(d.group),
+	)
+}
+
+// pruneTree removes anything under d.path that has no counterpart in
+// d.source. A destination entry also counts as having a counterpart if
+// d.source has the same relative path with a ".tmpl" suffix appended, since
+// copySourceFile (via file.Ensure) strips that suffix when writing —
+// otherwise every templated file would be pruned immediately after being
+// copied.
+func pruneTree(d *Dir) error {
+	log.Printf("pruning destination directory %s", d.path)
+
+	return filepath.WalkDir(d.path, func(path string, entry fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+
+		rel, err := filepath.Rel(d.path, path)
+		if err != nil {
+			return err
+		}
+		if rel == "." {
+			return nil // don't prune the root itself
+		}
+
+		if sourceEntryExists(d.source, rel) {
+			return nil
+		}
+
+		log.Printf("pruning %s", path)
+		if err := os.RemoveAll(path); err != nil {
+			return fmt.Errorf("failed to prune %s: %w", path, err)
+		}
+		if entry.IsDir() {
+			return filepath.SkipDir // already removed
+		}
+		return nil
+	})
+}
+
+func sourceEntryExists(source, rel string) bool {
+	if _, err := os.Lstat(filepath.Join(source, rel)); err == nil {
+		return true
+	}
+	_, err := os.Lstat(filepath.Join(source, rel) + ".tmpl")
+	return err == nil
+}