refactor: move pkg/ to internal/ and update imports

Restructure project by relocating package contents from pkg/ to internal/ to better reflect internal-only usage. This commit is initial step to prepare project for public api

internal/manager/managers.go

@@ -0,0 +1,114 @@
+// This file was originally part of the project "LURE - Linux User REpository", created by Elara Musayelyan.
+// It has been modified as part of "ALR - Any Linux Repository" by the ALR Authors.
+//
+// ALR - Any Linux Repository
+// Copyright (C) 2025 The ALR Authors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package manager
+
+import (
+	"os"
+	"os/exec"
+)
+
+var Args []string
+
+type Opts struct {
+	NoConfirm bool
+	Args      []string
+}
+
+var DefaultOpts = &Opts{
+	NoConfirm: false,
+}
+
+var managers = []Manager{
+	NewPacman(),
+	NewAPT(),
+	NewDNF(),
+	NewYUM(),
+	NewAPK(),
+	NewZypper(),
+	NewAPTRpm(),
+}
+
+// Register registers a new package manager
+func Register(m Manager) {
+	managers = append(managers, m)
+}
+
+// Manager represents a system package manager
+type Manager interface {
+	// Name returns the name of the manager.
+	Name() string
+	// Format returns the packaging format of the manager.
+	// 	Examples: rpm, deb, apk
+	Format() string
+	// Returns true if the package manager exists on the system.
+	Exists() bool
+
+	// Sync fetches repositories without installing anything
+	Sync(*Opts) error
+	// Install installs packages
+	Install(*Opts, ...string) error
+	// Remove uninstalls packages
+	Remove(*Opts, ...string) error
+	// Upgrade upgrades packages
+	Upgrade(*Opts, ...string) error
+	// InstallLocal installs packages from local files rather than repos
+	InstallLocal(*Opts, ...string) error
+	// UpgradeAll upgrades all packages
+	UpgradeAll(*Opts) error
+	// ListInstalled returns all installed packages mapped to their versions
+	ListInstalled(*Opts) (map[string]string, error)
+	//
+	IsInstalled(string) (bool, error)
+}
+
+// Detect returns the package manager detected on the system
+func Detect() Manager {
+	for _, mgr := range managers {
+		if mgr.Exists() {
+			return mgr
+		}
+	}
+	return nil
+}
+
+// Get returns the package manager with the given name
+func Get(name string) Manager {
+	for _, mgr := range managers {
+		if mgr.Name() == name {
+			return mgr
+		}
+	}
+	return nil
+}
+
+func setCmdEnv(cmd *exec.Cmd) {
+	cmd.Env = os.Environ()
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stderr
+	cmd.Stderr = os.Stderr
+}
+
+func ensureOpts(opts *Opts) *Opts {
+	if opts == nil {
+		opts = DefaultOpts
+	}
+	opts.Args = append(opts.Args, Args...)
+	return opts
+}