#!/usr/bin/env tclsh

# char2ent.tcl - Opens an HTML or XML file with special characters
#       (diacritics) written in plain text, replaces these special
#       characters with appropriate HTML or XML entities and writes the
#       output to a new file.
#
# Author: Luciano Espirito Santo
#
# History
#
#   Version 1.0 2004-11-18  Luciano Espirito Santo
#       First version. Alpha stage.
#
#       KNOWN ISSUES:
#       - No user-proof measures, no error or exception handling, no nothing!
#         No guarantees! Use it at your own risk!
#       - Tested on Windows 98 and Linux only.
#
#       TODO:
#       - Extend it so it can handle all possible characters (Unicode).
#       - Make the ability to do the INVERSE operation (that would include the
#         ability to tell non-escaped entities from escaped entities and NOT
#         replace the escaped entities.
#       - Make it handle STDIN.
#
#       LICENSE: BSD
#
# How to use it:
#
# char2ent.tcl  --help

# ----------------------------------------------------------------
# Do not change anything below this point unless you know what you're doing.


# Print help text and exit if '--help' is the only argument
if  {[llength $argc] == 1 && [lindex $argv 0] == "--help"}  {
    puts  ""
    puts  "char2ent, by Luciano Espirito Santo - 2004"
    puts  ""
    puts  {Usage: char2ent -[option]  "input file"  "output file"}
    puts  ""
    puts  "Possible options:"
    puts  "-h: convert special characters to HTML entities"
    puts  "-x: convert special characters to XML entities"
    puts  ""
    puts  {"input file" MUST exist}
    puts  {"output file" is created automatically if it does not exist}
    puts  {"input file" and "output file" MUST NOT be the same file}
    puts  ""
    puts  {Example: char2ent -x "sample.xml" "converted.xml"}
    puts  ""
    exit
}

# Complain and exit if option is neither '-h' nor '-x'
if  {[lindex $argv 0] != "-h" && [lindex $argv 0] != "-x"}      {
    puts  "Error! Try 'char2ent --help' to see how to use this program.\n"
    exit
}

# Complain and exit if not exactly 3 arguments (option, input, output) are found
if  {$argc != 3}    {
    puts  "Error! You must use exactly 3 arguments.\n"
    puts  "$argv\n"
    puts  "Error! Try 'char2ent --help' to see how to use this program.\n"
    exit
}

# Complain and exit if input file does not exist
if  {! [file exists [lindex $argv 1]]   {
    puts  "Error! File \"[lindex $argv 1]\" not found!\n"
    exit
}

# Complain and exit if input file is not readable
if  {! [file readable [lindex $argv 1]]}    {
    puts  "Error! Permission denied to read [ lindex $argv 1 ]!\n"
    exit
}

# Complain if input file and output file are the same
if  {[lindex $argv 1] == [lindex $argv 2]}  {
    puts  "Error! \"input file\" and \"output file\" must not be the same.\n"
    exit
}

# Try to open input file for reading.
# Complain and exit in case of errors.
if  {[catch {set IF [open [lindex $argv 1] r]} IFerror]}  {
    puts  "Error! $IFerror\n"
    exit
}

# Try to open output file for writing.
# Complain, close input file and exit in case of errors.
if  {[catch {set OF [open [lindex $argv 2] w]} OFerror]}    {
    close $IF
    puts  "Error! $OFerror\n"
    exit
}


# ================================================
# Two files open. No errors this far. Let's replace.

set  CHARS  {
    ª  º  À  Á  Â  Ã  Ä  Å  Æ  Ç
    È  É  Ê  Ë  Ì  Í  Î  Ï  Ð  Ñ
    Ò  Ó  Ô  Õ  Ö  Ø  Ù  Ú  Û  Ü
    Ý  Þ  ß  à  á  â  ã  ä  å  æ
    ç  è  é  ê  ë  ì  í  î  ï  ð
    ñ  ò  ó  ô  õ  ö  ø  ù  ú  û
    ü  ý  þ  ÿ  Œ  œ  Ÿ
}

set  HTML  {
    ª  º  À    Á    Â Ã    Ä
    Å &Aelig; Ç    È    É    Ê Ë
    Ì    Í    Î Ï  Ð   Ñ    Ò
    Ó    Ô Õ    Ö  Ø    Ù    Ú
    Û Ü  Ý    Þ ß à    á
    â ã    ä  å æ ç    è
    é    ê ë  ì    í    î ï  ð
    ñ    ò    ó    ô õ    ö  ø
    ù    ú    û ü  ý    þ ÿ
    &Oelig; œ Ÿ
}

set  XML  {
    ª  º  À  Á  Â  Ã  Ä  Å  Æ
    Ç  È  É  Ê  Ë  Ì  Í  Î  Ï
    Ð  Ñ  Ò  Ó  Ô  Õ  Ö  Ø  Ù
    Ú  Û  Ü  Ý  Þ  ß  à  á  â
    ã  ä  å  æ  ç  è  é  ê  ë
    ì  í  î  ï  ð  ñ  ò  ó  ô
    õ  ö  ø  ù  ú  û  ü  ý  þ
    ÿ  Œ œ Ÿ
}


set TEXT [read $IF]

for {set i 0}   {$i < [llength $CHARS]} {incr i}    {

    switch -- [lindex $argv 0]  {
        "-h"    {set REPL [lindex $HTML $i]}
        "-x"    {set REPL [lindex $XML  $i]}
    }

    set TEXT [string map "[lindex $CHARS $i] $REPL" $TEXT]
}


puts -nonewline $OF $TEXT
close $IF
close $OF

exit