package windows

import (
	"fmt"
	"path/filepath"
	"strings"
)

// processSnapshot is deliberately small so the matching invariant can be
// tested without a Windows host. NextImagePath returns more=false only after a
// successful end-of-snapshot; any enumeration or image-path failure is an
// error, rather than evidence that the target is not running.
type processSnapshot interface {
	NextImagePath() (path string, more bool, err error)
	Close() error
}

type processSnapshotFactory func() (processSnapshot, error)

func entrypointIsRunning(entrypoint string, newSnapshot processSnapshotFactory) (bool, error) {
	target, err := canonicalProcessPath(entrypoint)
	if err != nil {
		return false, fmt.Errorf("canonicalize target entrypoint: %w", err)
	}

	snapshot, err := newSnapshot()
	if err != nil {
		return false, fmt.Errorf("create process snapshot: %w", err)
	}
	defer snapshot.Close()

	for {
		path, more, err := snapshot.NextImagePath()
		if err != nil {
			return false, fmt.Errorf("enumerate process image path: %w", err)
		}
		if !more {
			return false, nil
		}
		candidate, err := canonicalProcessPath(path)
		if err != nil {
			return false, fmt.Errorf("canonicalize process image path: %w", err)
		}
		if strings.EqualFold(target, candidate) {
			return true, nil
		}
	}
}

func canonicalProcessPath(path string) (string, error) {
	abs, err := filepath.Abs(path)
	if err != nil {
		return "", err
	}
	return filepath.Clean(abs), nil
}