package main

import (
	"errors"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"

	"github.com/distatus/battery"
	"github.com/shirou/gopsutil/host"
	"github.com/shirou/gopsutil/process"
)

type environmentInfo interface {
	getenv(key string) string
	getcwd() string
	homeDir() string
	hasFiles(pattern string) bool
	hasFolder(folder string) bool
	getFileContent(file string) string
	getPathSeperator() string
	getCurrentUser() string
	isRunningAsRoot() bool
	getHostName() (string, error)
	getRuntimeGOOS() string
	getPlatform() string
	hasCommand(command string) bool
	runCommand(command string, args ...string) (string, error)
	runShellCommand(shell string, command string) string
	lastErrorCode() int
	getArgs() *args
	getBatteryInfo() (*battery.Battery, error)
	getShellName() string
}

type environment struct {
	args *args
	cwd  string
}

type commandError struct {
	exitCode int
}

func (e *commandError) Error() string {
	return fmt.Sprintf("%d", e.exitCode)
}

func (env *environment) getenv(key string) string {
	return os.Getenv(key)
}

func (env *environment) getcwd() string {
	if env.cwd != "" {
		return env.cwd
	}
	correctPath := func(pwd string) string {
		// on Windows, and being case sentisitive and not consistent and all, this gives silly issues
		return strings.Replace(pwd, "c:", "C:", 1)
	}
	if env.args != nil && *env.args.PWD != "" {
		env.cwd = correctPath(*env.args.PWD)
		return env.cwd
	}
	dir, err := os.Getwd()
	if err != nil {
		return ""
	}
	env.cwd = correctPath(dir)
	return env.cwd
}

func (env *environment) hasFiles(pattern string) bool {
	cwd := env.getcwd()
	pattern = cwd + env.getPathSeperator() + pattern
	matches, err := filepath.Glob(pattern)
	if err != nil {
		return false
	}
	return len(matches) > 0
}

func (env *environment) hasFolder(folder string) bool {
	_, err := os.Stat(folder)
	return !os.IsNotExist(err)
}

func (env *environment) getFileContent(file string) string {
	content, err := ioutil.ReadFile(file)
	if err != nil {
		return ""
	}
	return string(content)
}

func (env *environment) getPathSeperator() string {
	return string(os.PathSeparator)
}

func (env *environment) getCurrentUser() string {
	user := os.Getenv("USER")
	if user == "" {
		user = os.Getenv("USERNAME")
	}
	return user
}

func (env *environment) getHostName() (string, error) {
	hostName, err := os.Hostname()
	if err != nil {
		return "", err
	}
	return cleanHostName(hostName), nil
}

func (env *environment) getRuntimeGOOS() string {
	return runtime.GOOS
}

func (env *environment) getPlatform() string {
	if runtime.GOOS == "windows" {
		return "windows"
	}
	p, _, _, _ := host.PlatformInformation()

	return p
}

func (env *environment) runCommand(command string, args ...string) (string, error) {
	out, err := exec.Command(command, args...).Output()

	var exerr *exec.ExitError
	if errors.As(err, &exerr) {
		return "", &commandError{exitCode: exerr.ExitCode()}
	}
	if err != nil {
		return "", err
	}

	return strings.TrimSpace(string(out)), nil
}

func (env *environment) runShellCommand(shell string, command string) string {
	out, err := exec.Command(shell, "-c", command).Output()
	if err != nil {
		log.Println(err)
		return ""
	}
	return strings.TrimSpace(string(out))
}

func (env *environment) hasCommand(command string) bool {
	_, err := exec.LookPath(command)
	return err == nil
}

func (env *environment) lastErrorCode() int {
	return *env.args.ErrorCode
}

func (env *environment) getArgs() *args {
	return env.args
}

func (env *environment) getBatteryInfo() (*battery.Battery, error) {
	return battery.Get(0)
}

func (env *environment) getShellName() string {
	pid := os.Getppid()
	p, _ := process.NewProcess(int32(pid))
	name, err := p.Name()
	if err != nil {
		return "unknown"
	}
	shell := strings.Replace(name, ".exe", "", 1)
	return strings.Trim(shell, " ")
}

func cleanHostName(hostName string) string {
	garbage := []string{
		".lan",
		".local",
		".localdomain",
	}
	for _, g := range garbage {
		if strings.HasSuffix(hostName, g) {
			hostName = strings.Replace(hostName, g, "", 1)
		}
	}
	return hostName
}