package main

import (
	"bytes"
	"errors"
	"fmt"
	"io/ioutil"
	"log"
	"net/url"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"
	"syscall"
	"time"

	"nvm/arch"
	"nvm/file"
	"nvm/node"
	"nvm/web"

	"github.com/blang/semver"
	"github.com/olekukonko/tablewriter"
)

const (
	NvmVersion = "1.1.9"
)

type Environment struct {
	settings        string
	root            string
	symlink         string
	arch            string
	node_mirror     string
	npm_mirror      string
	proxy           string
	originalpath    string
	originalversion string
	verifyssl       bool
}

var home = filepath.Clean(os.Getenv("NVM_HOME") + "\\settings.txt")
var symlink = filepath.Clean(os.Getenv("NVM_SYMLINK"))

var env = &Environment{
	settings:        home,
	root:            "",
	symlink:         symlink,
	arch:            os.Getenv("PROCESSOR_ARCHITECTURE"),
	node_mirror:     "",
	npm_mirror:      "",
	proxy:           "none",
	originalpath:    "",
	originalversion: "",
	verifyssl:       true,
}

func main() {
	args := os.Args
	detail := ""
	procarch := arch.Validate(env.arch)

	// Capture any additional arguments
	if len(args) > 2 {
		detail = args[2]
	}
	if len(args) > 3 {
		if args[3] == "32" || args[3] == "64" {
			procarch = args[3]
		}
	}
	if len(args) < 2 {
		help()
		return
	}

	if args[1] != "version" && args[1] != "v" {
		setup()
	}

	// Run the appropriate method
	switch args[1] {
	case "install":
		install(detail, procarch)
	case "uninstall":
		uninstall(detail)
	case "use":
		use(detail, procarch)
	case "list":
		list(detail)
	case "ls":
		list(detail)
	case "on":
		enable()
	case "off":
		disable()
	case "root":
		if len(args) == 3 {
			updateRootDir(args[2])
		} else {
			fmt.Println("\nCurrent Root: " + env.root)
		}
	case "v":
		fmt.Println(NvmVersion)
	case "version":
		fmt.Println(NvmVersion)
	case "arch":
		if strings.Trim(detail, " \r\n") != "" {
			detail = strings.Trim(detail, " \r\n")
			if detail != "32" && detail != "64" {
				fmt.Println("\"" + detail + "\" is an invalid architecture. Use 32 or 64.")
				return
			}
			env.arch = detail
			saveSettings()
			fmt.Println("Default architecture set to " + detail + "-bit.")
			return
		}
		_, a := node.GetCurrentVersion()
		fmt.Println("System Default: " + env.arch + "-bit.")
		fmt.Println("Currently Configured: " + a + "-bit.")
	case "proxy":
		if detail == "" {
			fmt.Println("Current proxy: " + env.proxy)
		} else {
			env.proxy = detail
			saveSettings()
		}
	case "current":
		inuse, _ := node.GetCurrentVersion()
		v, _ := semver.Make(inuse)
		err := v.Validate()

		if err != nil {
			fmt.Println(inuse)
		} else if inuse == "Unknown" {
			fmt.Println("No current version. Run 'nvm use x.x.x' to set a version.")
		} else {
			fmt.Println("v" + inuse)
		}

	//case "update": update()
	case "node_mirror":
		setNodeMirror(detail)
	case "npm_mirror":
		setNpmMirror(detail)
	default:
		help()
	}
}

// ===============================================================
// BEGIN | CLI functions
// ===============================================================
func setNodeMirror(uri string) {
	env.node_mirror = uri
	saveSettings()
}

func setNpmMirror(uri string) {
	env.npm_mirror = uri
	saveSettings()
}

/*
func update() {
  cmd := exec.Command("cmd", "/d", "echo", "testing")
  var output bytes.Buffer
  var _stderr bytes.Buffer
  cmd.Stdout = &output
  cmd.Stderr = &_stderr
  perr := cmd.Run()
  if perr != nil {
      fmt.Println(fmt.Sprint(perr) + ": " + _stderr.String())
      return
  }
}
*/

func getVersion(version string, cpuarch string, localInstallsOnly ...bool) (string, string, error) {
	requestedVersion := version
	cpuarch = strings.ToLower(cpuarch)

	if cpuarch != "" {
		if cpuarch != "32" && cpuarch != "64" && cpuarch != "all" {
			return version, cpuarch, errors.New("\"" + cpuarch + "\" is not a valid CPU architecture. Must be 32 or 64.")
		}
	} else {
		cpuarch = env.arch
	}

	if cpuarch != "all" {
		cpuarch = arch.Validate(cpuarch)
	}

	if version == "" {
		return "", cpuarch, errors.New("A version argument is required but missing.")
	}

	// If user specifies "latest" version, find out what version is
	if version == "latest" {
		version = getLatest()
	}

	if version == "lts" {
		version = getLTS()
	}

	if version == "newest" {
		installed := node.GetInstalled(env.root)
		if len(installed) == 0 {
			return version, "", errors.New("No versions of node.js found. Try installing the latest by typing nvm install latest.")
		}

		version = installed[0]
	}

	if version == "32" || version == "64" {
		cpuarch = version
		v, _ := node.GetCurrentVersion()
		version = v
	}

	version = strings.Replace(version, "v", "", 1)
	v, err := semver.Make(version)
	if err == nil {
		err = v.Validate()
	}

	if err == nil {
		// if the user specifies only the major/minor version, identify the latest
		// version applicable to what was provided.
		sv := strings.Split(version, ".")
		if len(sv) < 3 {
			version = findLatestSubVersion(version)
		} else {
			version = cleanVersion(version)
		}

		version = strings.Replace(version, "v", "", 1)
	} else if strings.Contains(err.Error(), "No Major.Minor.Patch") {
		latestLocalInstall := false
		if len(localInstallsOnly) > 0 {
			latestLocalInstall = localInstallsOnly[0]
		}
		version = findLatestSubVersion(version, latestLocalInstall)
		if len(version) == 0 {
			err = errors.New("Unrecognized version: \"" + requestedVersion + "\"")
		}
	}

	return version, cpuarch, err
}

func install(version string, cpuarch string) {
	requestedVersion := version
	args := os.Args
	lastarg := args[len(args)-1]

	if lastarg == "--insecure" {
		env.verifyssl = false
	}

	v, a, err := getVersion(version, cpuarch)
	version = v
	cpuarch = a

	if err != nil {
		if strings.Contains(err.Error(), "No Major.Minor.Patch") {
			sv, sverr := semver.Make(version)
			if sverr == nil {
				sverr = sv.Validate()
			}
			if sverr != nil {
				version = findLatestSubVersion(version)
				if len(version) == 0 {
					sverr = errors.New("Unrecognized version: \"" + requestedVersion + "\"")
				}
			}
			err = sverr
		}

		if err != nil {
			fmt.Println(err.Error())
			if version == "" {
				fmt.Println(" ")
				help()
			}
			return
		}
	}

	if err != nil {
		fmt.Println("\"" + requestedVersion + "\" is not a valid version.")
		fmt.Println("Please use a valid semantic version number, \"lts\", or \"latest\".")
		return
	}

	if checkVersionExceedsLatest(version) {
		fmt.Println("Node.js v" + version + " is not yet released or available.")
		return
	}

	if cpuarch == "64" && !web.IsNode64bitAvailable(version) {
		fmt.Println("Node.js v" + version + " is only available in 32-bit.")
		return
	}

	// Check to see if the version is already installed
	if !node.IsVersionInstalled(env.root, version, cpuarch) {
		if !node.IsVersionAvailable(version) {
			url := web.GetFullNodeUrl("index.json")
			fmt.Println("\nVersion " + version + " is not available.\n\nThe complete list of available versions can be found at " + url)
			return
		}

		// Make the output directories
		os.Mkdir(filepath.Join(env.root, "v"+version), os.ModeDir)
		os.Mkdir(filepath.Join(env.root, "v"+version, "node_modules"), os.ModeDir)

		// Warn the user if they're attempting to install without verifying the remote SSL cert
		if !env.verifyssl {
			fmt.Println("\nWARNING: The remote SSL certificate will not be validated during the download process.\n")
		}

		// Download node
		append32 := node.IsVersionInstalled(env.root, version, "64")
		append64 := node.IsVersionInstalled(env.root, version, "32")
		if (cpuarch == "32" || cpuarch == "all") && !node.IsVersionInstalled(env.root, version, "32") {
			success := web.GetNodeJS(env.root, version, "32", append32)
			if !success {
				os.RemoveAll(filepath.Join(env.root, "v"+version, "node_modules"))
				fmt.Println("Could not download node.js v" + version + " 32-bit executable.")
				return
			}
		}
		if (cpuarch == "64" || cpuarch == "all") && !node.IsVersionInstalled(env.root, version, "64") {
			success := web.GetNodeJS(env.root, version, "64", append64)
			if !success {
				os.RemoveAll(filepath.Join(env.root, "v"+version, "node_modules"))
				fmt.Println("Could not download node.js v" + version + " 64-bit executable.")
				return
			}
		}

		if file.Exists(filepath.Join(env.root, "v"+version, "node_modules", "npm")) {
			fmt.Println("\n\nInstallation complete. If you want to use this version, type\n\nnvm use " + version)
			return
		}

		// If successful, add npm
		npmv := getNpmVersion(version)
		success := web.GetNpm(env.root, getNpmVersion(version))
		if success {
			fmt.Printf("Installing npm v" + npmv + "...")

			// new temp directory under the nvm root
			tempDir := filepath.Join(env.root, "temp")

			// Extract npm to the temp directory
			err := file.Unzip(filepath.Join(tempDir, "npm-v"+npmv+".zip"), filepath.Join(tempDir, "nvm-npm"))

			// Copy the npm and npm.cmd files to the installation directory
			tempNpmBin := filepath.Join(tempDir, "nvm-npm", "cli-"+npmv, "bin")

			// Support npm < 6.2.0
			if file.Exists(tempNpmBin) == false {
				tempNpmBin = filepath.Join(tempDir, "nvm-npm", "npm-"+npmv, "bin")
			}

			if file.Exists(tempNpmBin) == false {
				log.Fatal("Failed to extract npm. Could not find " + tempNpmBin)
			}

			// Standard npm support
			os.Rename(filepath.Join(tempNpmBin, "npm"), filepath.Join(env.root, "v"+version, "npm"))
			os.Rename(filepath.Join(tempNpmBin, "npm.cmd"), filepath.Join(env.root, "v"+version, "npm.cmd"))

			// npx support
			if _, err := os.Stat(filepath.Join(tempNpmBin, "npx")); err == nil {
				os.Rename(filepath.Join(tempNpmBin, "npx"), filepath.Join(env.root, "v"+version, "npx"))
				os.Rename(filepath.Join(tempNpmBin, "npx.cmd"), filepath.Join(env.root, "v"+version, "npx.cmd"))
			}

			npmSourcePath := filepath.Join(tempDir, "nvm-npm", "npm-"+npmv)

			if file.Exists(npmSourcePath) == false {
				npmSourcePath = filepath.Join(tempDir, "nvm-npm", "cli-"+npmv)
			}

			moveNpmErr := os.Rename(npmSourcePath, filepath.Join(env.root, "v"+version, "node_modules", "npm"))
			if moveNpmErr != nil {
				// sometimes Windows can take some time to enable access to large amounts of files after unzip, use exponential backoff to wait until it is ready
				for _, i := range [5]int{1, 2, 4, 8, 16} {
					time.Sleep(time.Duration(i) * time.Second)
					moveNpmErr = os.Rename(npmSourcePath, filepath.Join(env.root, "v"+version, "node_modules", "npm"))
					if moveNpmErr == nil {
						break
					}
				}

			}

			if err == nil && moveNpmErr == nil {
				// Remove the temp directory
				// may consider keep the temp files here
				os.RemoveAll(tempDir)

				fmt.Println("\n\nInstallation complete. If you want to use this version, type\n\nnvm use " + version)
			} else if moveNpmErr != nil {
				fmt.Println("Error: Unable to move directory " + npmSourcePath + " to node_modules: " + moveNpmErr.Error())
			} else {
				fmt.Println("Error: Unable to install NPM: " + err.Error())
			}
		} else {
			fmt.Println("Could not download npm for node v" + version + ".")
			fmt.Println("Please visit https://github.com/npm/cli/releases/tag/v" + npmv + " to download npm.")
			fmt.Println("It should be extracted to " + env.root + "\\v" + version)
		}

		// Reset the SSL verification
		env.verifyssl = true

		// If this is ever shipped for Mac, it should use homebrew.
		// If this ever ships on Linux, it should be on bintray so it can use yum, apt-get, etc.
		return
	} else {
		fmt.Println("Version " + version + " is already installed.")
		return
	}

}

func uninstall(version string) {
	// Make sure a version is specified
	if len(version) == 0 {
		fmt.Println("Provide the version you want to uninstall.")
		help()
		return
	}

	if strings.ToLower(version) == "latest" {
		version = getLatest()
	} else if strings.ToLower(version) == "lts" {
		version = getLTS()
	} else if strings.ToLower(version) == "newest" {
		installed := node.GetInstalled(env.root)
		if len(installed) == 0 {
			fmt.Println("No versions of node.js found. Try installing the latest by typing nvm install latest.")
			return
		}

		version = installed[0]
	}

	version = cleanVersion(version)

	// Determine if the version exists and skip if it doesn't
	if node.IsVersionInstalled(env.root, version, "32") || node.IsVersionInstalled(env.root, version, "64") {
		fmt.Printf("Uninstalling node v" + version + "...")
		v, _ := node.GetCurrentVersion()
		if v == version {
			_, err := runElevated(fmt.Sprintf(`"%s" cmd /C rmdir "%s"`, filepath.Join(env.root, "elevate.cmd"), filepath.Clean(env.symlink)))
			if err != nil {
				fmt.Println(fmt.Sprint(err))
				return
			}
		}
		e := os.RemoveAll(filepath.Join(env.root, "v"+version))
		if e != nil {
			fmt.Println("Error removing node v" + version)
			fmt.Println("Manually remove " + filepath.Join(env.root, "v"+version) + ".")
		} else {
			fmt.Printf(" done")
		}
	} else {
		fmt.Println("node v" + version + " is not installed. Type \"nvm list\" to see what is installed.")
	}
	return
}

func findLatestSubVersion(version string, localOnly ...bool) string {
	if len(localOnly) > 0 && localOnly[0] {
		installed := node.GetInstalled(env.root)
		result := ""
		for _, v := range installed {
			if strings.HasPrefix(v, "v"+version) {
				if result != "" {
					current, _ := semver.New(strings.Replace(result, "v", "", 1))
					next, _ := semver.New(strings.Replace(v, "v", "", 1))
					if current.LT(*next) {
						result = v
					}
				} else {
					result = v
				}
			}
		}

		if len(strings.TrimSpace(result)) > 0 {
			return result
		}
	}

	url := web.GetFullNodeUrl("latest-v" + version + ".x" + "/SHASUMS256.txt")
	content := web.GetRemoteTextFile(url)
	re := regexp.MustCompile("node-v(.+)+msi")
	reg := regexp.MustCompile("node-v|-x.+")
	latest := reg.ReplaceAllString(re.FindString(content), "")
	return latest
}

func use(version string, cpuarch string, reload ...bool) {
	v, a, err := getVersion(version, cpuarch, true)
	version = v
	cpuarch = a

	if err != nil {
		if strings.Contains(err.Error(), "No Major.Minor.Patch") {
			fmt.Printf("node v%v (%v-bit) is not installed or cannot be found.", v, a)
		} else {
			fmt.Println(err.Error())
		}
		return
	}

	// Make sure the version is installed. If not, warn.
	if !node.IsVersionInstalled(env.root, version, cpuarch) {
		fmt.Println("node v" + version + " (" + cpuarch + "-bit) is not installed.")
		if cpuarch == "32" {
			if node.IsVersionInstalled(env.root, version, "64") {
				fmt.Println("\nDid you mean node v" + version + " (64-bit)?\nIf so, type \"nvm use " + version + " 64\" to use it.")
			}
		}
		if cpuarch == "64" {
			if node.IsVersionInstalled(env.root, version, "32") {
				fmt.Println("\nDid you mean node v" + version + " (32-bit)?\nIf so, type \"nvm use " + version + " 32\" to use it.")
			}
		}
		return
	}

	// Remove symlink if it already exists
	sym, _ := os.Stat(env.symlink)
	if sym != nil {
		_, err := runElevated(fmt.Sprintf(`"%s" cmd /C rmdir "%s"`, filepath.Join(env.root, "elevate.cmd"), filepath.Clean(env.symlink)))
		if err != nil {
			fmt.Println(fmt.Sprint(err))
		}

		// // Return if the symlink already exists
		// if ok {
		// 	fmt.Print(err)
		// 	return
		// }
	}

	// Create new symlink
	var ok bool
	ok, err = runElevated(fmt.Sprintf(`"%s" cmd /C mklink /D "%s" "%s"`, filepath.Join(env.root, "elevate.cmd"), filepath.Clean(env.symlink), filepath.Join(env.root, "v"+version)))
	if err != nil {
		if strings.Contains(err.Error(), "file already exists") {
			ok, err = runElevated(fmt.Sprintf(`"%s" cmd /C rmdir "%s"`, filepath.Join(env.root, "elevate.cmd"), filepath.Clean(env.symlink)))
			reloadable := true
			if len(reload) > 0 {
				reloadable = reload[0]
			}
			if err != nil {
				fmt.Println(fmt.Sprint(err))
			} else if reloadable {
				use(version, cpuarch, false)
				return
			}
		} else {
			fmt.Print(fmt.Sprint(err))
		}
	}
	if !ok {
		return
	}

	// Use the assigned CPU architecture
	cpuarch = arch.Validate(cpuarch)
	nodepath := filepath.Join(env.root, "v"+version, "node.exe")
	node32path := filepath.Join(env.root, "v"+version, "node32.exe")
	node64path := filepath.Join(env.root, "v"+version, "node64.exe")
	node32exists := file.Exists(node32path)
	node64exists := file.Exists(node64path)
	nodeexists := file.Exists(nodepath)
	if node32exists && cpuarch == "32" { // user wants 32, but node.exe is 64
		if nodeexists {
			os.Rename(nodepath, node64path) // node.exe -> node64.exe
		}
		os.Rename(node32path, nodepath) // node32.exe -> node.exe
	}
	if node64exists && cpuarch == "64" { // user wants 64, but node.exe is 32
		if nodeexists {
			os.Rename(nodepath, node32path) // node.exe -> node32.exe
		}
		os.Rename(node64path, nodepath) // node64.exe -> node.exe
	}
	fmt.Println("Now using node v" + version + " (" + cpuarch + "-bit)")
}

func useArchitecture(a string) {
	if strings.ContainsAny("32", os.Getenv("PROCESSOR_ARCHITECTURE")) {
		fmt.Println("This computer only supports 32-bit processing.")
		return
	}
	if a == "32" || a == "64" {
		env.arch = a
		saveSettings()
		fmt.Println("Set to " + a + "-bit mode")
	} else {
		fmt.Println("Cannot set architecture to " + a + ". Must be 32 or 64 are acceptable values.")
	}
}

func list(listtype string) {
	if listtype == "" {
		listtype = "installed"
	}
	if listtype != "installed" && listtype != "available" {
		fmt.Println("\nInvalid list option.\n\nPlease use on of the following\n  - nvm list\n  - nvm list installed\n  - nvm list available")
		help()
		return
	}

	if listtype == "installed" {
		fmt.Println("")
		inuse, a := node.GetCurrentVersion()

		v := node.GetInstalled(env.root)

		for i := 0; i < len(v); i++ {
			version := v[i]
			isnode, _ := regexp.MatchString("v", version)
			str := ""
			if isnode {
				if "v"+inuse == version {
					str = str + "  * "
				} else {
					str = str + "    "
				}
				str = str + regexp.MustCompile("v").ReplaceAllString(version, "")
				if "v"+inuse == version {
					str = str + " (Currently using " + a + "-bit executable)"
					//            str = ansi.Color(str,"green:black")
				}
				fmt.Printf(str + "\n")
			}
		}
		if len(v) == 0 {
			fmt.Println("No installations recognized.")
		}
	} else {
		_, lts, current, stable, unstable, _ := node.GetAvailable()

		releases := 20

		data := make([][]string, releases, releases+5)
		for i := 0; i < releases; i++ {
			release := make([]string, 4, 6)

			release[0] = ""
			release[1] = ""
			release[2] = ""
			release[3] = ""

			if len(current) > i {
				if len(current[i]) > 0 {
					release[0] = current[i]
				}
			}

			if len(lts) > i {
				if len(lts[i]) > 0 {
					release[1] = lts[i]
				}
			}

			if len(stable) > i {
				if len(stable[i]) > 0 {
					release[2] = stable[i]
				}
			}

			if len(unstable) > i {
				if len(unstable[i]) > 0 {
					release[3] = unstable[i]
				}
			}

			data[i] = release
		}

		fmt.Println("")
		table := tablewriter.NewWriter(os.Stdout)
		table.SetHeader([]string{"   Current  ", "    LTS     ", " Old Stable ", "Old Unstable"})
		table.SetBorders(tablewriter.Border{Left: true, Top: false, Right: true, Bottom: false})
		table.SetAlignment(tablewriter.ALIGN_CENTER)
		table.SetCenterSeparator("|")
		table.AppendBulk(data) // Add Bulk Data
		table.Render()

		fmt.Println("\nThis is a partial list. For a complete list, visit https://nodejs.org/en/download/releases")
	}
}

func enable() {
	dir := ""
	files, _ := ioutil.ReadDir(env.root)
	for _, f := range files {
		if f.IsDir() {
			isnode, _ := regexp.MatchString("v", f.Name())
			if isnode {
				dir = f.Name()
			}
		}
	}
	fmt.Println("nvm enabled")
	if dir != "" {
		use(strings.Trim(regexp.MustCompile("v").ReplaceAllString(dir, ""), " \n\r"), env.arch)
	} else {
		fmt.Println("No versions of node.js found. Try installing the latest by typing nvm install latest")
	}
}

func disable() {
	ok, err := runElevated(fmt.Sprintf(`"%s" cmd /C rmdir "%s"`, filepath.Join(env.root, "elevate.cmd"), filepath.Clean(env.symlink)))
	if !ok {
		return
	}
	if err != nil {
		fmt.Print(fmt.Sprint(err))
	}

	fmt.Println("nvm disabled")
}

func help() {
	fmt.Println("\nRunning version " + NvmVersion + ".")
	fmt.Println("\nUsage:")
	fmt.Println(" ")
	fmt.Println("  nvm arch                     : Show if node is running in 32 or 64 bit mode.")
	fmt.Println("  nvm current                  : Display active version.")
	fmt.Println("  nvm install <version> [arch] : The version can be a specific version, \"latest\" for the latest current version, or \"lts\" for the")
	fmt.Println("                                 most recent LTS version. Optionally specify whether to install the 32 or 64 bit version (defaults")
	fmt.Println("                                 to system arch). Set [arch] to \"all\" to install 32 AND 64 bit versions.")
	fmt.Println("                                 Add --insecure to the end of this command to bypass SSL validation of the remote download server.")
	fmt.Println("  nvm list [available]         : List the node.js installations. Type \"available\" at the end to see what can be installed. Aliased as ls.")
	fmt.Println("  nvm on                       : Enable node.js version management.")
	fmt.Println("  nvm off                      : Disable node.js version management.")
	fmt.Println("  nvm proxy [url]              : Set a proxy to use for downloads. Leave [url] blank to see the current proxy.")
	fmt.Println("                                 Set [url] to \"none\" to remove the proxy.")
	fmt.Println("  nvm node_mirror [url]        : Set the node mirror. Defaults to https://nodejs.org/dist/. Leave [url] blank to use default url.")
	fmt.Println("  nvm npm_mirror [url]         : Set the npm mirror. Defaults to https://github.com/npm/cli/archive/. Leave [url] blank to default url.")
	fmt.Println("  nvm uninstall <version>      : The version must be a specific version.")
	//  fmt.Println("  nvm update                   : Automatically update nvm to the latest version.")
	fmt.Println("  nvm use [version] [arch]     : Switch to use the specified version. Optionally use \"latest\", \"lts\", or \"newest\".")
	fmt.Println("                                 \"newest\" is the latest installed version. Optionally specify 32/64bit architecture.")
	fmt.Println("                                 nvm use <arch> will continue using the selected version, but switch to 32/64 bit mode.")
	fmt.Println("  nvm root [path]              : Set the directory where nvm should store different versions of node.js.")
	fmt.Println("                                 If <path> is not set, the current root will be displayed.")
	fmt.Println("  nvm version                  : Displays the current running version of nvm for Windows. Aliased as v.")
	fmt.Println(" ")
}

// ===============================================================
// END | CLI functions
// ===============================================================

// ===============================================================
// BEGIN | Utility functions
// ===============================================================
func checkVersionExceedsLatest(version string) bool {
	//content := web.GetRemoteTextFile("http://nodejs.org/dist/latest/SHASUMS256.txt")
	url := web.GetFullNodeUrl("latest/SHASUMS256.txt")
	content := web.GetRemoteTextFile(url)
	re := regexp.MustCompile("node-v(.+)+msi")
	reg := regexp.MustCompile("node-v|-x.+")
	latest := reg.ReplaceAllString(re.FindString(content), "")
	var vArr = strings.Split(version, ".")
	var lArr = strings.Split(latest, ".")
	for index := range lArr {
		lat, _ := strconv.Atoi(lArr[index])
		ver, _ := strconv.Atoi(vArr[index])
		//Should check for valid input (checking for conversion errors) but this tool is made to trust the user
		if ver < lat {
			return false
		} else if ver > lat {
			return true
		}
	}
	return false
}

func cleanVersion(version string) string {
	re := regexp.MustCompile("\\d+.\\d+.\\d+")
	matched := re.FindString(version)

	if len(matched) == 0 {
		re = regexp.MustCompile("\\d+.\\d+")
		matched = re.FindString(version)
		if len(matched) == 0 {
			matched = version + ".0.0"
		} else {
			matched = matched + ".0"
		}
		fmt.Println(matched)
	}

	return matched
}

// Given a node.js version, returns the associated npm version
func getNpmVersion(nodeversion string) string {
	_, _, _, _, _, npm := node.GetAvailable()
	return npm[nodeversion]
}

func getLatest() string {
	url := web.GetFullNodeUrl("latest/SHASUMS256.txt")
	content := web.GetRemoteTextFile(url)
	re := regexp.MustCompile("node-v(.+)+msi")
	reg := regexp.MustCompile("node-v|-x.+")
	return reg.ReplaceAllString(re.FindString(content), "")
}

func getLTS() string {
	_, ltsList, _, _, _, _ := node.GetAvailable()
	// ltsList has already been numerically sorted
	return ltsList[0]
}

func updateRootDir(path string) {
	_, err := os.Stat(path)
	if err != nil {
		fmt.Println(path + " does not exist or could not be found.")
		return
	}

	currentRoot := env.root
	env.root = filepath.Clean(path)

	// Copy command files
	os.Link(filepath.Clean(currentRoot+"/elevate.cmd"), filepath.Clean(env.root+"/elevate.cmd"))
	os.Link(filepath.Clean(currentRoot+"/elevate.vbs"), filepath.Clean(env.root+"/elevate.vbs"))

	saveSettings()

	if currentRoot != env.root {
		fmt.Println("\nRoot has been changed from " + currentRoot + " to " + path)
	}
}

func runElevated(command string, forceUAC ...bool) (bool, error) {
	uac := false
	if len(forceUAC) > 0 {
		uac = forceUAC[0]
	}

	if uac {
		// Alternative elevation option at stackoverflow.com/questions/31558066/how-to-ask-for-administer-privileges-on-windows-with-go
		cmd := exec.Command(filepath.Join(env.root, "elevate.cmd"), command)
		var output bytes.Buffer
		var _stderr bytes.Buffer
		cmd.Stdout = &output
		cmd.Stderr = &_stderr
		perr := cmd.Run()
		if perr != nil {
			return false, errors.New(fmt.Sprint(perr) + ": " + _stderr.String())
		}
	}

	c := exec.Command("cmd") // dummy executable that actually needs to exist but we'll overwrite using .SysProcAttr

	// Based on the official docs, syscall.SysProcAttr.CmdLine doesn't exist.
	// But it does and is vital:
	// https://github.com/golang/go/issues/15566#issuecomment-333274825
	// https://medium.com/@felixge/killing-a-child-process-and-all-of-its-children-in-go-54079af94773
	c.SysProcAttr = &syscall.SysProcAttr{CmdLine: command}

	var stderr bytes.Buffer
	c.Stderr = &stderr

	err := c.Run()
	if err != nil {
		msg := stderr.String()
		if strings.Contains(msg, "not have sufficient privilege") && uac {
			return runElevated(command, false)
		}
		// fmt.Println(fmt.Sprint(err) + ": " + stderr.String())
		return false, errors.New(fmt.Sprint(err) + ": " + msg)
	}

	return true, nil
}

func saveSettings() {
	content := "root: " + strings.Trim(env.root, " \n\r") + "\r\narch: " + strings.Trim(env.arch, " \n\r") + "\r\nproxy: " + strings.Trim(env.proxy, " \n\r") + "\r\noriginalpath: " + strings.Trim(env.originalpath, " \n\r") + "\r\noriginalversion: " + strings.Trim(env.originalversion, " \n\r")
	content = content + "\r\nnode_mirror: " + strings.Trim(env.node_mirror, " \n\r") + "\r\nnpm_mirror: " + strings.Trim(env.npm_mirror, " \n\r")
	ioutil.WriteFile(env.settings, []byte(content), 0644)
}

// NOT USED?
/*
func useArchitecture(a string) {
  if strings.ContainsAny("32",os.Getenv("PROCESSOR_ARCHITECTURE")) {
    fmt.Println("This computer only supports 32-bit processing.")
    return
  }
  if a == "32" || a == "64" {
    env.arch = a
    saveSettings()
    fmt.Println("Set to "+a+"-bit mode.")
  } else {
    fmt.Println("Cannot set architecture to "+a+". Must be 32 or 64 are acceptable values.")
  }
}
*/
// ===============================================================
// END | Utility functions
// ===============================================================

func setup() {
	lines, err := file.ReadLines(env.settings)
	if err != nil {
		fmt.Println("\nERROR", err)
		os.Exit(1)
	}

	// Process each line and extract the value
	m := make(map[string]string)
	for _, line := range lines {
		line = strings.TrimSpace(line)
		line = os.ExpandEnv(line)
		res := strings.Split(line, ":")
		if len(res) < 2 {
			continue
		}
		m[res[0]] = strings.TrimSpace(strings.Join(res[1:], ":"))
	}

	if val, ok := m["root"]; ok {
		env.root = filepath.Clean(val)
	}
	if val, ok := m["originalpath"]; ok {
		env.originalpath = filepath.Clean(val)
	}
	if val, ok := m["originalversion"]; ok {
		env.originalversion = val
	}
	if val, ok := m["arch"]; ok {
		env.arch = val
	}
	if val, ok := m["node_mirror"]; ok {
		env.node_mirror = val
	}
	if val, ok := m["npm_mirror"]; ok {
		env.npm_mirror = val
	}

	if val, ok := m["proxy"]; ok {
		if val != "none" && val != "" {
			if strings.ToLower(val[0:4]) != "http" {
				val = "http://" + val
			}
			res, err := url.Parse(val)
			if err == nil {
				web.SetProxy(res.String(), env.verifyssl)
				env.proxy = res.String()
			}
		}
	}

	web.SetMirrors(env.node_mirror, env.npm_mirror)
	env.arch = arch.Validate(env.arch)

	// Make sure the directories exist
	_, e := os.Stat(env.root)
	if e != nil {
		fmt.Println(env.root + " could not be found or does not exist. Exiting.")
		return
	}
}