package procmon

import (
	"fmt"
	"io/ioutil"
	"os"
	"strings"

	"github.com/evilsocket/opensnitch/daemon/core"
)

func GetPIDFromINode(inode int) int {
	expect := fmt.Sprintf("socket:[%d]", inode)
	found := -1

	forEachProcess(func(pid int, path string, args []string) bool {
		// for every descriptor
		fdPath := fmt.Sprintf("/proc/%d/fd/", pid)
		if descriptors, err := ioutil.ReadDir(fdPath); err == nil {
			for _, desc := range descriptors {
				descLink := fmt.Sprintf("%s%s", fdPath, desc.Name())
				// resolve the symlink and compare to what we expect
				if link, err := os.Readlink(descLink); err == nil && link == expect {
					found = pid
					return true
				}
			}
		}
		// keep looping
		return false
	})

	return found
}

func parseCmdLine(proc *Process) {
	if data, err := ioutil.ReadFile(fmt.Sprintf("/proc/%d/cmdline", proc.ID)); err == nil {
		for i, b := range data {
			if b == 0x00 {
				data[i] = byte(' ')
			}
		}

		args := strings.Split(string(data), " ")
		for _, arg := range args {
			arg = core.Trim(arg)
			if arg != "" {
				proc.Args = append(proc.Args, arg)
			}
		}
	}
}

func parseEnv(proc *Process) {
	if data, err := ioutil.ReadFile(fmt.Sprintf("/proc/%d/environ", proc.ID)); err == nil {
		for _, s := range strings.Split(string(data), "\x00") {
			parts := strings.SplitN(core.Trim(s), "=", 2)
			if parts != nil && len(parts) == 2 {
				key := core.Trim(parts[0])
				val := core.Trim(parts[1])
				proc.Env[key] = val
			}
		}
	}
}

func FindProcess(pid int) *Process {
	linkName := fmt.Sprintf("/proc/%d/exe", pid)
	if core.Exists(linkName) == false {
		return nil
	}

	if link, err := os.Readlink(linkName); err == nil && core.Exists(link) == true {
		proc := NewProcess(pid, link)

		parseCmdLine(proc)
		parseEnv(proc)

		return proc
	}
	return nil
}