// ============================================================================ simple golang builder (mwx'2026)
package main

import (
	"bufio"
	"bytes"
	"encoding/json"
	"flag"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"strings"
	"time"

	"github.com/AlecAivazis/survey/v2"
)

var version = "1.19.3"

var UPDATEURL = "http://gozilla.fhi.mpg.de/gbld"

var oses = []string{"darwin", "linux", "windows"}
var arches = []string{"arm64", "amd64"}

var GO string
var GOIMPORTS string

var done chan bool
var r1, r2, r3 *regexp.Regexp

func main() { // ========================================================================================== main
  
  checkforupdate(UPDATEURL)

  if len(os.Args) == 1 {                                                               // read predefined builds
    c, err := os.ReadFile("gbld.menu.json")
    if err == nil {
      var sel []string
      var buildjson map[string][]string

      err := json.Unmarshal([]byte(c), &buildjson)
      if err == nil {
        for k := range buildjson {
          sel = append(sel, k)
        }
        tmp := ""
        err = survey.AskOne(&survey.Select{Message: "Select build", Options: sel}, &tmp)
        os.Args = []string{"gbld"}
        os.Args = append(os.Args, buildjson[tmp]...)
      } else {
        PE(err.Error())
        os.Exit(0);
      }
    } else {
      os.Args = []string{"gbld","-b","-i","-1",dirName()}
    }
  }

  opt_b := flag.Bool("b", false, "")
  opt_1 := flag.Bool("1", false, "")
  opt_i := flag.Bool("i", false, "")
  opt_x := flag.Bool("x", false, "")
  opt_c := flag.String("c", "", "")
  opt_o := flag.String("o", "", "")
  opt_a := flag.Bool("a", false, "")
  opt_v := flag.Bool("v", false, "")
  opt_h := flag.Bool("h", false, "")
  opt_u := flag.Bool("u", false, "")

  flag.Usage = func() {
    P()
    info()
    P()
    P(Cw("Usage:"))
    P(Cy("  gbld [-b] [-1] [-i] [-c <CMD>] [-o <OPTIONS>] [build name]"))
    P(Cy("  gbld [-a] [-u]"))
    P(Cw("    -b             build only"))
    P(Cw("    -1             run only once"))
    P(Cw("    -i             run gpimports before build"))
    P(Cw("    -o  <OPTIONS>  exec options"))
    P(Cw("    -c  <CMD>      run command after build"))
    P(Cw("    -v             show version"))
    P(Cw("    -h             show help"))
    P(Cw("    -a             build for all platforms"))
    P(Cw("    -u             upload builds to gozilla"))
    P()
    P(Cw("  · if build is supplied the current directory name will be used"))
    P()
    P(Cw("  · if no option supplied try to read '") + Cy("gbld.menu.json") + Cw("'"))
    P(Cm(`      {`))
    P(Cm(`        "build": ["-b","gbld"],`))
    P(Cm(`        "help":  ["-h"]`))
    P(Cm(`      }`))
    P()
    P(Cw("  · if no option is supplied and no '") + Cy("gbld.menu.json") + Cw("' is available"))
    P(Cw("    the current directory name with ") + Cy("-b -i -1") + Cw(" as options will be used"))
    P()
  }

  flag.Parse()

  path, err := exec.LookPath("go") // ··························································· check for 'go'
  if err != nil {
    fmt.Println(Crb("Error: ") + Cwb("go") + " not found")
    os.Exit(0)

  }
  GO = path


  path, err = exec.LookPath("goimports") // ·············································· check for 'goimports'
  if err != nil {
    fmt.Println(Crb("Error: ") + Cwb("goimports") + " not found")
    os.Exit(0)
  }
  GOIMPORTS = path


  if *opt_v { // ·················································································· show version
    info()
    os.Exit(0)
  }

  if *opt_h { // ····················································································· show help
    flag.Usage()
    os.Exit(0)
  }

  name := flag.Arg(0) // ································································ command line arguments
  if len(name) == 0 {
    name=dirName()
    if len(name) == 0 {
      flag.Usage()
      os.Exit(0)
    }
  }

  file := name + ".go"
  if !fileExists(file) {
    P(Crb("file not found: " + file))
    os.Exit(0)
  }

  var ot int64 = 0
  var st int = 1
  var xmd *exec.Cmd = nil

  if (!*opt_1 && !*opt_a && !*opt_u) {
    PN("\033[2J\033[1;1H")
  }
    info()

  if *opt_a { // ······························································· build for other platforms
    targetversion:=gettargetversion(file)
    P(Ccb("build for all platforms"))
    for _, osys := range oses {
      for _, arch := range arches {
        
        ofile:="bin/"+name+"_"+targetversion+"_"+osys+"_"+arch
        P(Cy(ofile))
        
        cmd := exec.Command(GO, "build", "-o", ofile, name)
        cmd.Env = append(os.Environ(), "GOOS="+osys, "GOARCH="+arch)
        cmd.Run()
      }
    }
    
    os.WriteFile("bin/version.txt", []byte(targetversion), 0644)
    
  }

  if *opt_u { // ······································································ upload builds to gozilla
    targetversion:=gettargetversion(file)
    P(Ccb("upload builds to gozilla"))
 
    for _, osys := range oses {
      for _, arch := range arches {
        ofile:="bin/"+name+"_"+targetversion+"_"+osys+"_"+arch
        _, err := os.Stat(ofile)
        if err == nil {

          cmd := exec.Command("ssh","root@gozilla","rm", "/db/www/"+name+"/*_"+osys+"_"+arch   )
          P(Cy(cmd))
          cmd.Run()
          
          
          cmd = exec.Command("scp",ofile, "root@gozilla:/db/www/"+name)
          P(Cy(cmd))
          cmd.Run()
        }
      }
    }
    _, err := os.Stat("bin/version.txt")
    if err == nil {
      cmd := exec.Command("scp","bin/version.txt", "root@gozilla:/db/www/"+name)
      P(Cy(cmd))
      cmd.Run()
    }
  
  }


  if (*opt_a || *opt_u) { os.Exit(0) }
 
    r1 = regexp.MustCompile("^\\.")
  r2 = regexp.MustCompile("build\\.go")
  r3 = regexp.MustCompile("\\.go$")

  for { // ------------------------------------------------------------------------------------------- main loop
    lmf := lmf("./")

    var dt int64 = 0

    if fileExists(name) {
      dt = lmf - filemodtime(name)
    } else {
      dt = 1
    }

    if (dt > 0 && ot != lmf) || st == 1 { // ·············································· new version detected

      if st == 0 && !*opt_1{
        PN("\033[2J\033[1;1H")
      }
      P(Cc("--- start compiling " + file + " ---"))

      stopRunning(xmd)

      o := "" // ········································································· increase build number

      readFile, err := os.Open("build.go")
      if err == nil {
        defer readFile.Close()
        backup("build.go")
        fileScanner := bufio.NewScanner(readFile)
        fileScanner.Split(bufio.ScanLines)
        r := regexp.MustCompile("var\\s+build\\s*=\\s*\"(.*)\"$")
        for fileScanner.Scan() {
          line := fileScanner.Text()
          s := r.FindStringSubmatch(line)
          if len(s) > 0 {
            b := Atoi(s[1]) + 1
            o = o + "var build = \"" + Itoa(b) + "\"\n"
            P("build:", s[1], "->", b)
          } else {
            o = o + line + "\n"
          }
        }
        os.WriteFile("build.go", []byte(o), 0644)
      }

      targetversion:=""
      readFile, err = os.Open(file)
      if err == nil {
        fileScanner := bufio.NewScanner(readFile)
        fileScanner.Split(bufio.ScanLines)
        r := regexp.MustCompile("var\\s+version\\s*=\\s*\"(.*)\"$")
        for fileScanner.Scan() {
          line := fileScanner.Text()
          s := r.FindStringSubmatch(line)
          if len(s) > 0 {
            targetversion=s[1]
          }
        }
        readFile.Close()
      }

      if (targetversion=="") {
        PE("target version not found")
        os.Exit(0)
      }

      if *opt_i { // ············································································· run goimports
        re := regexp.MustCompile(`(?s)import\s*\((.*?)\)`)
        files, err := os.ReadDir(".")
        if err != nil { fmt.Printf("Error: %v\n", err); return }
        
        for _, f := range files {
          if !f.IsDir() && strings.HasSuffix(f.Name(), ".go") {
            fileName := f.Name()
            cmd := exec.Command("goimports", fileName)
            output, err := cmd.Output()
            if err != nil { continue }
            origContent, _ := os.ReadFile(fileName)
            tempMatch := re.FindStringSubmatch(string(output))
            if len(tempMatch) < 2 { continue }
            newImportBlock := tempMatch[1]
            updatedContent := ReplaceFirst(re,string(origContent),fmt.Sprintf("import (%s)", newImportBlock))
            if (string(origContent) != updatedContent) {
              backup(fileName)
              PF("%s %s\n",Cw("imports updated:"),Cmb(fileName))
              os.WriteFile(fileName, []byte(updatedContent), 0644)
            }
          }
        }

      }

      cmd := exec.Command("go", "build", "-o", "bin/"+name, name)

      PF("%s %s\n", Cw("running:"), Cyb("go build "+name))

      out, err := cmd.CombinedOutput()

      if err != nil { // ·········································································· build failed

        PN(Cy(string(out)))
        P(Cr("--- build failed: " + name + " ---"))

      } else { // ·············································································· build succeeded

        P(Cb("--- compiling done: " + name + " ---"))

        if len(*opt_c) > 0 { // ··························································· execute post command
          params := strings.Fields(*opt_c)
          app := params[0]
          args := params[1:]

          P(Cw(*opt_c))
          xmd = exec.Command(app, args...)
          xmd.Stdout = os.Stdout
          xmd.Stdin = os.Stdin
          xmd.Stderr = os.Stderr
          xmd.Run()
        }

        if !*opt_b && !*opt_a {
          stopRunning(xmd)

          args := []string{}
          if len(*opt_o) > 0 {
            args = strings.Fields(*opt_o)
          }

          xmd = exec.Command("./bin/"+name, args...) // ······································· start new build
          var stdoutBuf, stderrBuf bytes.Buffer
          xmd.Stdout = io.MultiWriter(os.Stdout, &stdoutBuf)
          xmd.Stderr = io.MultiWriter(os.Stderr, &stderrBuf)
          xmd.Start()

          PF("%s %d\n", Cw("process started:"), xmd.Process.Pid)
        }

        P(Cg("--- end building: " + name + " ---"))
        if *opt_x {
          os.Exit(0)
        }
      }
      ot = lmf
    }

    if *opt_1 {
      os.Exit(0)
    }

    st = 0
    time.Sleep(500 * time.Millisecond)
  }
}


func backup(src string) { // ---------------------------------------------------------------------- backup files
  sourceFile,_ := os.Open(src)
  defer sourceFile.Close()
  dst:=SF("./tmp/%s.%s",src,time.Now().Format("20060102150405"))
  destFile,_ := os.Create(dst)
  defer destFile.Close()
  io.Copy(destFile, sourceFile)
  destFile.Sync()
  destFile.Close()
}

// ===================================================================================================== SUPPORT

func gettargetversion(file string) string { // ------------------------------------------- detect target version
  targetversion:=""
  readFile, err := os.Open(file)
  if err == nil {
    fileScanner := bufio.NewScanner(readFile)
    fileScanner.Split(bufio.ScanLines)
    r := regexp.MustCompile("var\\s+version\\s*=\\s*\"(.*)\"$")
    for fileScanner.Scan() {
      line := fileScanner.Text()
      s := r.FindStringSubmatch(line)
      if len(s) > 0 {
        targetversion=s[1]
      }
    }
    readFile.Close()
  }

  if (targetversion=="") {
    PE("target version not found")
    os.Exit(0)
  }
  
  return targetversion
}


func lmf(dir string) int64 { // -------------------------------------- get last modification date from .go files
  var tmax int64 = 0
  files, err := os.ReadDir(dir)
  if err == nil {
    for _, file := range files {
      if r3.MatchString(file.Name()) {
        if !r1.MatchString(file.Name()) && !r2.MatchString(file.Name()) {
          tf := filemodtime(file.Name())
          if tf > tmax {
            tmax = tf
          }
        }
      }
    }
  }
  return tmax
}

func stopRunning(cmd *exec.Cmd) { // -------------------------------------------------- stop running old process
  if cmd == nil || cmd.ProcessState != nil && cmd.ProcessState.Exited() || cmd.Process == nil {
    return
  }

  err := cmd.Process.Kill()
  if err == nil {
    cmd.Wait()
    P("process stopped:", cmd.Process.Pid)
  }
}

func fileExists(filename string) bool { // ------------------------------------------------ check if file exists
  info, err := os.Stat(filename)
  if os.IsNotExist(err) {
    return false
  }
  return !info.IsDir()
}

func dirName() string { // ------------------------------------------------------- get name of current directory
  pwd,err := os.Getwd()
  if err == nil { 
    return filepath.Base(pwd)
  } 
  return ""
}

func info() { // ------------------------------------------------------------------------------------- show info
  PF("%s (%s (%s), toolbox %s, %s)\n", Cwb("gbld - simple golang builder"),
    Cgb("v"+version), Cgb(build), Cgb("v"+tbversion), Ccb("mwx'2026"))
}

// ========================================================================================================= END