package sysutils

import (
	"fmt"
	"os"
	"strconv"
	"strings"

	"golang.org/x/sys/unix"
	"r00t2.io/sysutils/envs"
	"r00t2.io/sysutils/errs"
)

// GetIDState returns current ID/elevation information. An IDState should *not* be explicitly created/defined.
func GetIDState() (ids IDState) {

	var err error

	ids.RUID, ids.EUID, ids.SUID = unix.Getresuid()
	ids.uidsChecked = true
	ids.RGID, ids.EGID, ids.SGID = unix.Getresgid()
	ids.gidsChecked = true

	ids.SudoEnvCmd = envs.HasEnv("SUDO_COMMAND")
	ids.SudoEnvHome = envs.HasEnv("SUDO_HOME")
	ids.SudoEnvGroup = envs.HasEnv("SUDO_GID")
	ids.SudoEnvUser = envs.HasEnv("SUDO_UID") || envs.HasEnv("SUDO_USER")
	if ids.SudoEnvCmd || ids.SudoEnvHome || ids.SudoEnvGroup || ids.SudoEnvUser {
		ids.SudoEnvVars = true
	}
	ids.sudoChecked = true

	// PID 1 will *always* be root, so that can return a false positive for sudo.
	if os.Getppid() != 1 {
		ids.stat = new(unix.Stat_t)
		if err = unix.Stat(
			fmt.Sprintf("/proc/%d/stat", os.Getppid()),
			ids.stat,
		); err != nil {
			err = nil
		} else {
			ids.PPIDUidMatch = ids.RUID == int(ids.stat.Uid)
			ids.ppidUidChecked = true
			ids.PPIDGidMatch = ids.RGID == int(ids.stat.Gid)
			ids.ppidGidChecked = true
		}
	} else {
		ids.ppidUidChecked = true
		ids.ppidGidChecked = true
	}

	return
}

// NsToInode splits a namespace identifier (e.g. `net:[12345]`) to its type (e.g. `net`) and inode (e.g. `12345`).
func NsToInode(ns string) (typ string, inode uint64, err error) {

	var fields []string

	fields = strings.SplitN(ns, ":", 2)

	if len(fields) != 2 {
		err = errs.ErrInvalidNs
		return
	}

	fields[1] = strings.TrimPrefix(fields[1], "[")
	fields[1] = strings.TrimSuffix(fields[1], "]")

	if inode, err = strconv.ParseUint(fields[1], 10, 64); err != nil {
		return
	}

	typ = fields[0]

	return
}