package apply

import (
	"errors"
	"os"
	"path/filepath"

	"git.novox.be/novox/mesh-sdk/go/declaration"
)

// declaredFiles is the path of every file a declaration declares.
func declaredFiles(resources []declaration.Resource) map[string]bool {
	out := map[string]bool{}
	for _, r := range resources {
		if f, ok := r.(*declaration.File); ok {
			out[filepath.Clean(f.Path)] = true
		}
	}
	return out
}

// mountsAFileNotThere is the first mount source of a container that is a file the declaration declares and is not
// on the machine yet, or "" (novox/hq issue 1873): the runtime makes a missing source a directory.
func mountsAFileNotThere(c *declaration.Container, files map[string]bool) string {
	for _, v := range c.Volumes {
		src := mountSource(v)
		if !filepath.IsAbs(src) || !files[filepath.Clean(src)] {
			continue
		}
		if _, err := os.Lstat(src); errors.Is(err, os.ErrNotExist) {
			return src
		}
	}
	return ""
}

// clearRuntimesEmptyDirectory removes what a container runtime leaves at a file's path when it mounted the file before
// it was there (novox/hq issue 1873): an empty directory, in the mesh's own tree by its path and by where its path
// leads, owned by the engine's own account. It says what it removed, or "" when nothing was. Anything else at the path
// is left for the write to meet as before: a directory with anything in it, or one outside the tree, is never removed.
func clearRuntimesEmptyDirectory(path string) (string, error) {
	info, err := os.Lstat(path)
	if err != nil || !info.IsDir() || !inTheMeshsTree(path) {
		return "", nil
	}
	if uid, _, ok := ownerOf(info); !ok || uid != os.Geteuid() {
		return "", nil
	}
	entries, err := os.ReadDir(path)
	if err != nil || len(entries) > 0 {
		return "", nil
	}
	if err := os.Remove(path); err != nil {
		return "", err
	}
	return "removed the empty directory a container runtime left at " + path + ", where this file belongs " +
		"(novox/hq issue 1873)", nil
}