package Ernad::Email;

use strict;
use warnings;

use Carp qw(confess);
use Data::Dumper;
use Encode;
use File::Basename;
use File::Slurp;
#use File::Slurper;
use MIME::Entity;
use File::Path;
use File::Temp qw/ tempfile tempdir /;
use Text::Wrapper;

## form issue nucleus
sub prepare_email {
  my $doc=shift;
  my $sheet_name=shift // '';
  my $save_email=shift // '';
  my $verbose=shift // '';
  $verbose=0;
  my $e=$main::e or confess 'Where is my erimp?';
  my $text_doc;
  my $html_doc;
  ## case of a single doc
  if(ref $doc eq 'XML::LibXML::Document') {
    $text_doc=$doc;
    $html_doc=$doc;
  }
  else {
    my $ref_xml;
    $text_doc=$doc->{'text'};
    $ref_xml=ref($text_doc);
    if(not $ref_xml eq 'XML::LibXML::Document') {
      confess 'Your doc->{html} is not a document.';
    }
    $html_doc=$doc->{'html'};
    $ref_xml=ref($html_doc);
    if(not $ref_xml eq 'XML::LibXML::Document') {
      confess 'Your doc->{html} is not a document.';
    }
  }
  if(not $e) {
    #$e=$Erimp::e // $main::e;
    $e=$main::e;
  }
  if(not ref($e) eq 'Ernad::Erimp') {
    confess 'Where is my erimp?';
  }
  if(not ref($e) eq 'Ernad::Erimp') {
    confess 'Where is my erimp?';
  }
  ## fixme. I have to form the headers from one doc, but
  ## which one? Here I use the html doc
  my $headers=&form_headers($html_doc,$e,$sheet_name);
  my $top = MIME::Entity->build(%$headers);
  ## create attachments
  my $sheet_dir=$e->{'dir'}->{'style'};
  my $sheet_name_end="_$sheet_name".$e->{'const'}->{'xsl_ext'};
  my $sheet_file;
  ## save file is a path/file expression
  if($save_email) {
    my $save_email_dir=dirname($save_email);
    if(not -d $save_email_dir) {
      mkpath($save_email_dir);
    }
  }
  ## text first
  $sheet_file="$sheet_dir/email_text".$sheet_name_end;
  if(-f $sheet_file) {
    my $text=&form_body($text_doc,$e,$sheet_name,'text');
    my $save_file=$save_email.'.txt';
    &File::Slurp::write_file($save_file,$text);
    $top->attach( Type => 'text/plain',
                  Description => basename($save_email).' text',
                  Charset => 'UTF-8',
                  Path => $save_file,
                  Encoding => '8BIT' );
  }
  else {
    $e->echo(__LINE__,"I did not find $sheet_file. The text part will be empty.");
  }
  ## html
  $sheet_file="$sheet_dir/email_html".$sheet_name_end;
  if(-f $sheet_file) {
    my $html=&form_body($html_doc,$e,$sheet_name,'html');
    my $save_file=$save_email.'.html';
    my $html_string=$html->toString();
    my $wrapper = Text::Wrapper->new(columns => 80, wrap_after=>'');
    my $wrapped_html_string=$wrapper->wrap($html_string);
    &File::Slurp::write_file($save_file,$wrapped_html_string);
    $top->attach( Type => 'text/html',
                  Description => basename($save_email).' HTML',
                  Charset => 'utf-8',
                  Data => $wrapped_html_string,
                  ## do not use Path => $save_file,
                  Encoding => '8BIT' );
  }
  else {
    $e->echo(__LINE__,"I did not find $sheet_file. The html part will be empty.");
  }
  ## general save_file
  my $save_file;
  my $save_fh;
  if($save_email) {
    $save_file=$save_email.'.mail';
  }
  else {
    ($save_fh, $save_file) = tempfile(DIR => '/tmp');
  }
  my $contents=$top->stringify;
  #$contents=decode_utf8($contents);
  #&File::Slurper::write_text($save_file,$contents,'utf8');
  &File::Slurp::write_file($save_file,$contents);
  if($verbose) {
    print "wrote $save_file\n";
  }
  return $save_file;
}

sub send_email {
  my $mail_file=shift // '';
  my $do_delete=shift // '';
  if(not $mail_file) {
    confess 'I have no email file to send.';
  }
  if(not -f $mail_file) {
    confess "I don't see your file '$mail_file'.";
  }
  my $e=$main::e // confess 'Where is my erimp?';
  ## sending it out
  my $exim_path=$e->{'conf'}->{'exim_path'};
  my $cmd = "cat $mail_file | $exim_path -t";
  ## could also be done by construction a default here ernad at domain
  my $envelope_from=$e->{'conf'}->{'envelope_from'} // '';
  if($envelope_from) {
    $cmd.=" -f $envelope_from";
  }
  system($cmd);
  ## remove the temporary file, keep the saved file
  if($mail_file=~m|^/tmp/| or $do_delete) {
    unlink $mail_file;
  }
}

sub form_headers {
  my $doc=shift;
  my $e=shift // '';
  my $sheet_name=shift // '';
  my $sheet="headers_$sheet_name";
  my $headers_doc=$e->{'t'}->transform($doc,$sheet) or
    confess "My transformation using $sheet failed.";
  my $headers_xp="/e:headers/e:header";
  my $xpc=$e->{'xpc'};
  my @headers=$xpc->findnodes($headers_xp,$headers_doc)->get_nodelist();
  my $h;
  foreach my $header (@headers) {
    #print $header->toString;
    my $value=$header->getAttribute('value') or next;
    my $name=$header->getAttribute('name');
    ## several headers with the same name are not supported!
    $h->{$name}=&email_header_encode($value);
  }
  #print Dumper $h;
  return $h;
}

sub form_body {
  my $doc=shift;
  my $e=shift // '';
  my $sheet_name=shift // '';
  my $type=shift;
  my $sheet="email_$type"."_$sheet_name";
  my $output;
  if($type eq 'text') {
    $output=$e->{'t'}->t($doc,$sheet,'chars') or
      confess "My transformation using $sheet failed.";
  }
  else {
    $output=$e->{'t'}->transform($doc,$sheet) or
      confess "My transformation using $sheet failed.";
  }
  return $output;
}

## http://stackoverflow.com/questions/11969775/how-to-encode-mail-subject-in-perl
sub email_header_encode {
  my $string=shift;
  if($string!~/[^\x00-\x7F]/) {
    return $string;
  }
  ## try separate out the email address
  if($string=~m|^(.*)\s+(<[^@]+@[^@]+>)$|) {
    my $name=$1;
    my $mad=$2;
    my $name_encoded=encode('MIME-Header', $name);
    return "$name_encoded $mad";
  }
  ## fallback case
  return encode('MIME-Header', $string);
}

1;