/*  Title:      Pure/System/isabelle_system.scala

     Author:     Makarius

 Isabelle system support (settings environment etc.).

 */

 package isabelle

 import java.util.regex.Pattern

 import java.util.Locale

 import java.io.{BufferedWriter, OutputStreamWriter, FileOutputStream,

   BufferedInputStream, FileInputStream, BufferedReader, InputStreamReader,

   File, IOException}

 import java.awt.{GraphicsEnvironment, Font}

 import scala.io.Source

 import scala.util.matching.Regex

 import scala.collection.mutable

 class Isabelle_System extends Standard_System

 {

   /** Isabelle environment **/

   private val environment: Map[String, String] =

   {

     import scala.collection.JavaConversions._

     val env0 = Map(java.lang.System.getenv.toList: _*) +

       ("THIS_JAVA" -> this_java())

     val isabelle_home =

       env0.get("ISABELLE_HOME") match {

         case None | Some("") =>

           val path = java.lang.System.getProperty("isabelle.home")

           if (path == null || path == "") error("Unknown Isabelle home directory")

           else path

         case Some(path) => path

       }

     Standard_System.with_tmp_file("settings") { dump =>

         val shell_prefix =

           if (Platform.is_windows) List(platform_root + "\\bin\\bash", "-l") else Nil

         val cmdline =

           shell_prefix ::: List(isabelle_home + "/bin/isabelle", "getenv", "-d", dump.toString)

         val (output, rc) = Standard_System.raw_exec(null, env0, true, cmdline: _*)

         if (rc != 0) error(output)

         val entries =

           for (entry <- Source.fromFile(dump).mkString split "\0" if entry != "") yield {

             val i = entry.indexOf('=')

             if (i <= 0) (entry -> "")

             else (entry.substring(0, i) -> entry.substring(i + 1))

           }

         Map(entries: _*) +

           ("HOME" -> java.lang.System.getenv("HOME")) +

           ("PATH" -> java.lang.System.getenv("PATH"))

       }

   }

   /* external processes */

   def execute(redirect: Boolean, args: String*): Process =

   {

     val cmdline =

       if (Platform.is_windows) List(platform_root + "\\bin\\env.exe") ++ args

       else args

     Standard_System.raw_execute(null, environment, redirect, cmdline: _*)

   }

   /* getenv */

   def getenv(name: String): String =

     environment.getOrElse(if (name == "HOME") "HOME_JVM" else name, "")

   def getenv_strict(name: String): String =

   {

     val value = getenv(name)

     if (value != "") value else error("Undefined environment variable: " + name)

   }

   override def toString = getenv("ISABELLE_HOME")

   /** file path specifications **/

   /* expand_path */

   private val Root = new Regex("(//+[^/]*|/)(.*)")

   private val Only_Root = new Regex("//+[^/]*|/")

   def expand_path(isabelle_path: String): String =

   {

     val result_path = new StringBuilder

     def init(path: String): String =

     {

       path match {

         case Root(root, rest) =>

           result_path.clear

           result_path ++= root

           rest

         case _ => path

       }

     }

     def append(path: String)

     {

       val rest = init(path)

       for (p <- rest.split("/") if p != "" && p != ".") {

         if (p == "..") {

           val result = result_path.toString

           if (!Only_Root.pattern.matcher(result).matches) {

             val i = result.lastIndexOf("/")

             if (result == "")

               result_path ++= ".."

             else if (result.substring(i + 1) == "..")

               result_path ++= "/.."

             else if (i < 0)

               result_path.length = 0

             else

               result_path.length = i

           }

         }

         else {

           val len = result_path.length

           if (len > 0 && result_path(len - 1) != '/')

             result_path += '/'

           result_path ++= p

         }

       }

     }

     val rest = init(isabelle_path)

     for (p <- rest.split("/")) {

       if (p.startsWith("$")) append(getenv_strict(p.substring(1)))

       else if (p == "~") append(getenv_strict("HOME"))

       else if (p == "~~") append(getenv_strict("ISABELLE_HOME"))

       else append(p)

     }

     result_path.toString

   }

   /* platform_path */

   def platform_path(isabelle_path: String): String =

     jvm_path(expand_path(isabelle_path))

   def platform_file(path: String) = new File(platform_path(path))

   /* source files */

   private def try_file(file: File) = if (file.isFile) Some(file) else None

   def source_file(path: String): Option[File] =

   {

     if (path.startsWith("/") || path == "")

       try_file(platform_file(path))

     else {

       val pure_file = platform_file("$ISABELLE_HOME/src/Pure/" + path)

       if (pure_file.isFile) Some(pure_file)

       else if (getenv("ML_SOURCES") != "")

         try_file(platform_file("$ML_SOURCES/" + path))

       else None

     }

   }

   /** system tools **/

   def bash_output(script: String): (String, Int) =

   {

     Standard_System.with_tmp_file("isabelle_script") { script_file =>

       Standard_System.with_tmp_file("isabelle_pid") { pid_file =>

         Standard_System.with_tmp_file("isabelle_output") { output_file =>

           Standard_System.write_file(script_file, script)

           val proc = execute(true, expand_path("$ISABELLE_HOME/lib/scripts/bash"), "group",

             script_file.getPath, pid_file.getPath, output_file.getPath)

           def kill(strict: Boolean) =

           {

             val pid =

               try { Some(Standard_System.read_file(pid_file)) }

               catch { case _: IOException => None }

             if (pid.isDefined) {

               var running = true

               var count = 10

               while (running && count > 0) {

                 if (execute(true, "kill", "-INT", "-" + pid.get).waitFor != 0)

                   running = false

                 else {

                   Thread.sleep(100)

                   if (!strict) count -= 1

                 }

               }

             }

           }

           val shutdown_hook = new Thread { override def run = kill(true) }

           Runtime.getRuntime.addShutdownHook(shutdown_hook)  // FIXME tmp files during shutdown?!?

           def cleanup() =

             try { Runtime.getRuntime.removeShutdownHook(shutdown_hook) }

             catch { case _: IllegalStateException => }

           val rc =

             try {

               try { proc.waitFor }  // FIXME read stderr (!??)

               catch { case e: InterruptedException => Thread.interrupted; kill(false); throw e }

             }

             finally {

               proc.getOutputStream.close

               proc.getInputStream.close

               proc.getErrorStream.close

               proc.destroy

               cleanup()

             }

           val output =

             try { Standard_System.read_file(output_file) }

             catch { case _: IOException => "" }

           (output, rc)

         }

       }

     }

   }

   def isabelle_tool(name: String, args: String*): (String, Int) =

   {

     getenv_strict("ISABELLE_TOOLS").split(":").find { dir =>

       val file = platform_file(dir + "/" + name)

       try { file.isFile && file.canRead && file.canExecute }

       catch { case _: SecurityException => false }

     } match {

       case Some(dir) =>

         Standard_System.process_output(

           execute(true, (List(expand_path(dir + "/" + name)) ++ args): _*))

       case None => ("Unknown Isabelle tool: " + name, 2)

     }

   }

   /* named pipes */

   def mk_fifo(): String =

   {

     val (result, rc) = isabelle_tool("mkfifo")

     if (rc == 0) result.trim

     else error(result)

   }

   def rm_fifo(fifo: String)

   {

     val (result, rc) = isabelle_tool("rmfifo", fifo)

     if (rc != 0) error(result)

   }

   def fifo_stream(fifo: String): BufferedInputStream =

   {

     // blocks until writer is ready

     val stream =

       if (Platform.is_windows) {

         val proc = execute(false, "cat", fifo)

         proc.getOutputStream.close

         proc.getErrorStream.close

         proc.getInputStream

       }

       else new FileInputStream(fifo)

     new BufferedInputStream(stream)

   }

   /** Isabelle resources **/

   /* components */

   def components(): List[String] =

     getenv("ISABELLE_COMPONENTS").split(":").toList

   /* find logics */

   def find_logics(): List[String] =

   {

     val ml_ident = getenv_strict("ML_IDENTIFIER")

     val logics = new mutable.ListBuffer[String]

     for (dir <- getenv_strict("ISABELLE_PATH").split(":")) {

       val files = platform_file(dir + "/" + ml_ident).listFiles()

       if (files != null) {

         for (file <- files if file.isFile) logics += file.getName

       }

     }

     logics.toList.sortWith(_ < _)

   }

   /* symbols */

   private def read_symbols(path: String): List[String] =

   {

     val file = platform_file(path)

     if (file.isFile) Source.fromFile(file).getLines().toList

     else Nil

   }

   val symbols = new Symbol.Interpretation(

     read_symbols("$ISABELLE_HOME/etc/symbols") :::

     read_symbols("$ISABELLE_HOME_USER/etc/symbols"))

   /* fonts */

   val font_family = "IsabelleText"

   def get_font(bold: Boolean): Font =

     new Font(font_family, if (bold) Font.BOLD else Font.PLAIN, 1)

   def install_fonts()

   {

     def create_font(bold: Boolean): Font =

     {

       val name =

         if (bold) "$ISABELLE_HOME/lib/fonts/IsabelleTextBold.ttf"

         else "$ISABELLE_HOME/lib/fonts/IsabelleText.ttf"

       Font.createFont(Font.TRUETYPE_FONT, platform_file(name))

     }

     def check_font() = get_font(false).getFamily == font_family

     if (!check_font()) {

       val font = create_font(false)

       val bold_font = create_font(true)

       val ge = GraphicsEnvironment.getLocalGraphicsEnvironment()

       ge.registerFont(font)

       // workaround strange problem with Apple's Java 1.6 font manager

       if (bold_font.getFamily == font_family) ge.registerFont(bold_font)

       if (!check_font()) error("Failed to install IsabelleText fonts")

     }

   }

 }