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## -*- Tcl -*- $

#
# htmllib.xotcl
#
# Author: Antti Salonen, as@fishpool.fi
#
# Copyright:
#
# This software is copyrighted by Fishpool Creations Oy Ltd.  The following 
# terms apply to all files associated with the software unless explicitly 
# disclaimed in individual files.
#
# The authors hereby grant permission to use, copy, modify, distribute,
# and license this software and its documentation for any purpose, provided
# that existing copyright notices are retained in all copies and that this
# notice is included verbatim in any distributions. No written agreement,
# license, or royalty fee is required for any of the authorized uses.
# Modifications to this software may be copyrighted by their authors
# and need not follow the licensing terms described here, provided that
# the new terms are clearly indicated on the first page of each file where
# they apply.
# 
# IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY
# FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
# ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
# DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
# 
# THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.  THIS SOFTWARE
# IS PROVIDED ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE
# NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
# MODIFICATIONS.
# 

package provide xotcl::htmllib 2.0
package require XOTcl 2.0

namespace eval ::xotcl::htmllib {
    namespace import ::xotcl::*

    @ @File {
	description {
	    This package provides the class HtmlBuilder, which can be used to 
	    generate HTML documents, or a part of a document.
	}
	authors {
	    Antti Salonen, as@fishpool.fi
	}
	date {
	    $Date: 2006/09/27 08:12:40 $
	}
    }
    
    #
    # the compressed parameter means that minimal HTML page are created
    # i.e. that space indentation is turned off
    #
    Class create HtmlBuilder -parameter {
	{compressed 0}
    }

    ## The constructor.
    ##
    ## The HtmlBuilder object has two instance variables. The document Tcl list
    ## contains the document as a list of strings. The document is stored as a list
    ## rather than a single string to allow further indentation of the whole
    ## document when necessary.
    ##   The indentLevel variable is the level of indentation, which is generally
    ## increased for the contents of any HTML element that may contain block-level
    ## elements. Typical examples would be <ul>, <li>, <td> and so forth.

    HtmlBuilder instproc init {} {
	my instvar document indentLevel
	set document [list] 
	set indentLevel 0
	return
    }


    HtmlBuilder instproc clear {} {
	my instvar document indentLevel

	set document [list]
	set indentLevel 0
	return
    }


    HtmlBuilder instproc getDocument {} {
	my instvar document
	return $document
    }


    HtmlBuilder instproc toString {} {
	my instvar document compressed
	set rvalue ""
	foreach line $document {
	    if {$compressed == "0"} {
		append rvalue "$line\n"
	    } else {
		## only new line for closing tags at the beginning 
		## of a document element
		if {[string equal -length 2 "</" $line]} {
		    append rvalue "$line\n"
		} else {
		    append rvalue "$line "
		}
	    }
	}
	return $rvalue
    }


    ## parseArguments - Parses the arguments in argList as described in the two
    ## additional Tcl lists. In addition to the arguments listed in the two 
    ## additional lists, the procedure also accepts arguments common to all
    ## HTML elements.
    ## Arguments:
    ##   argList - List of arguments to be parsed
    ##   argParamList - List of arguments that take a parameter
    ##   argNoParamList - List of arguments that don't take a parameter
    ## Returns:
    ##   A string with arguments to an HTML element.

    HtmlBuilder proc parseArguments {argList argParamList argNoParamList} {
	set rvalue ""
	set argParamList [concat $argParamList [list "ID" "CLASS" "STYLE" "TITLE" "LANG" "DIR"]]
	set param 0
	foreach arg $argList {
	    if {$param} {
		append rvalue "=\"$arg\""
		set param 0
	    } else {
		set arg2 [string toupper [string trimleft $arg "-"]]
		if {[lsearch -exact $argParamList $arg2] != -1} {
		    append rvalue " $arg2"
		    set param 1
		} elseif {[lsearch -exact $argNoParamList $arg2] != -1} {
		    append rvalue " $arg2"
		} else {
		    error "HTML syntax error: Invalid argument $arg2 to element"
		}
	    }
	}
	if {$param} {
	    error "HTML syntax error: Missing parameter to argument $arg2"
	}
	return $rvalue
    }


    ##############################################################################
    ## Low-level modification methods:
    ##
    ## The efficiency of these is of utmost importance if efficiency is an issue
    ## in the first place.
    ##
    ## addString
    ## addStringIncr
    ## addStringDecr
    ## addWhiteSpace
    ## addDocument
    ## mergeDocument


    ## Add a new arbitrary string to the document. This method is used by other
    ## modification methods, as well as the user directly to add content other than
    ## HTML elements. The string str is appended to the document with proper
    ## indentation.

    HtmlBuilder instproc addString {str} {
	my instvar document indentLevel compressed
	
	if {$compressed == "0"} {
	    for {set n 0} {$n < $indentLevel} {incr n} {
		append newLine "  "
	    }
	}
	append newLine $str
	lappend document $newLine
	
	return
    }

    ## Add a string to the document and increase the indentation level.

    HtmlBuilder instproc addStringIncr {str} {
	my instvar indentLevel
	my addString $str
	incr indentLevel
	return
    }


    ## Decrease the indentation level and add a string to the document.

    HtmlBuilder instproc addStringDecr {str} {
	my instvar indentLevel
	incr indentLevel -1
	my addString $str
	return
    }

    #
    # add the string and replace all line breaks in the
    # string with addLineBreak calls so that given plain text 
    # appears similar in HTML output

    HtmlBuilder instproc addStringWithLineBreaks {str} {
	while {[set idx [string first "\n" $str]] != -1} {
	    my addString [string range $str 0 [expr {$idx - 1}]]
	    my addLineBreak
	    set str [string range $str [expr {$idx + 1}] end]
	}
	my addString $str
    }
    
    ## Add a single line of white space to the HTML document.
    
    HtmlBuilder instproc addWhiteSpace {} {
	my addString ""
	return
    }

    ## Add the content of the document given as parameter.

    HtmlBuilder instproc addDocument {document} {
	set documentList [$document getDocument]
	
	foreach line $documentList {
	    my addString $line
	}
	return
    }

    ## Merge the content of the document given as a parameter. The difference
    ## to addDocument is that the document merged is destroyed.

    HtmlBuilder instproc mergeDocument {document} {
	set documentList [$document getDocument]
	
	foreach line $documentList {
	    my addString $line
	}
	$document destroy
	return
    }




    ##############################################################################
    ## HTML generation methods:                                                
    ##              
    ## The methods for generating various HTML structures are either a pair of 
    ## start and end methods, such as startParagraph and endParagraph, or a single
    ## method such as addListItem. Even if the closing tag for <p>, for
    ## example, is not required by the HTML specification, using the closing method
    ## is necessary to have the document properly indented.


    # Add a string to the document within <strong>...</strong>

    HtmlBuilder instproc addStringStrong {str} {
	my addString "<STRONG>$str</STRONG>"
	return
    }

    # Add a string to the document within <em>...</em>

    HtmlBuilder instproc addStringEmphasized {str} {
	my addString "<EM>$str</EM>"
	return
    }

    # Add a comment to the document <!-- ... -->

    HtmlBuilder instproc addComment {str} {
	my addString "<!-- $str -->"
	return
    }

    HtmlBuilder instproc addLineBreak {} {
	my addString "<BR>"
	return
    }

    ## startDocument - Start an HTML document. Currently all documents are HTML 4.0
    ## Transitional. HTML, BODY, HEAD and TITLE elements are added/started here.
    ## Optional arguments:
    ##   -title documentTitle (empty if not given)
    ##   -stylesheet externalStyleSheet
    ##   -bgcolor backgroundColour (deprecated in HTML 4.0)

    HtmlBuilder instproc startDocument {args} {
	set title ""
	foreach {name value} $args {
	    switch -- $name {
		-title {
		    set title $value
		}
		-stylesheet {
		    set stylesheet $value
		}
		-bgcolor {
		    set bgcolor $value
		}
	    }
	}
	my addString {<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/frameset.dtd">}
	my addWhiteSpace
	my addString {<HTML>}
	my addStringIncr {<HEAD>}
	my addString "<TITLE>$title</TITLE>"
	if {[info exists stylesheet]} {
	    my addString "<LINK REL=\"StyleSheet\" HREF=\"$stylesheet\" TYPE=\"text/css\">"
	}
	my addStringDecr {</HEAD>}
	my addWhiteSpace
	if {[info exists bgcolor]} {
	    my addStringIncr "<BODY BGCOLOR=\"$bgcolor\">"
	} else {
	    my addStringIncr {<BODY>}
	}
	return
    }

    ## endDocument - end an HTML document

    HtmlBuilder instproc endDocument {} {
	my addStringDecr {</BODY>}
	my addString {</HTML>}
	return
    }

    ## startParagraph - start a P element
    ## Optional arguments:
    ##   Common HTML arguments

    HtmlBuilder instproc startParagraph {args} {
	set attributes [HtmlBuilder parseArguments $args [list] [list]]
	my addStringIncr "<P$attributes>"
	return
    }

    ## endParagraph - end a P element

    HtmlBuilder instproc endParagraph {} {
	my addStringDecr {</P>}
	return
    }

    ## startAnchor - start an A element
    ## Optional arguments:
    ##   -href URI
    ##   -name cdata
    ##   -target frameTarget
    ##   Common HTML arguments

    HtmlBuilder instproc startAnchor {args} {
	set attributes [HtmlBuilder parseArguments $args \
			    [list "HREF" "NAME" "TARGET"] [list]]
	my addStringIncr "<A$attributes>"
	return
    }

    ## endAnchor - end an A element

    HtmlBuilder instproc endAnchor {args} {
	my addStringDecr {</A>}
	return
    }

    ## addAnchor - add an A element, using content as the visible link.
    ## Optional arguments:
    ##   -href URI
    ##   -name cdata
    ##   -target frameTarget
    ##   Common HTML arguments

    HtmlBuilder instproc addAnchor {content args} {
	eval my startAnchor $args
	my addString $content
	my endAnchor
	return
    }

    ## startUnorderedList - start a UL element
    ## Optional arguments:
    ##   Commmon HTML arguments

    HtmlBuilder instproc startUnorderedList {args} {
	set attributes [HtmlBuilder parseArguments $args [list] [list]]
	my addStringIncr "<UL$attributes>"
	return
    }

    ## endUnorderedList - end a UL element

    HtmlBuilder instproc endUnorderedList {} {
	my addStringDecr {</UL>}
	return
    }

    ## startListItem - start an LI element
    ## Optional arguments:
    ##   Common HTML arguments

    HtmlBuilder instproc startListItem {args} {
	set attributes [HtmlBuilder parseArguments $args [list] [list]]
	my addStringIncr "<LI$attributes>"
	return
    }

    ## endListItem - end an LI element

    HtmlBuilder instproc endListItem {} {
	my addStringDecr {</LI>}
	return
    }

    ## add a simple list item
    HtmlBuilder instproc addListItem {content} {
	my startListItem
	my addString $content
	my endListItem
    }

    ## startTable - start a TABLE element. Note that if the -border argument isn't
    ## used, by default the table are created with borders (<TABLE BORDER>).

    ## Optional arguments:
    ##   -border pixels
    ##   -cellpadding length
    ##   -cellspacing length
    ##   -summary text
    ##   -width length
    ##   -bgcolor  color spec
    ##   Common HTML arguments

    HtmlBuilder instproc startTable {args} {
	set attributes [HtmlBuilder parseArguments $args \
			    [list "BORDER" "CELLPADDING" "CELLSPACING" "SUMMARY" \
				 "WIDTH" "BGCOLOR"] [list]]
	if {[lsearch $args "-border"] == -1} {
	    append attributes " BORDER"
	}
	my addStringIncr "<TABLE$attributes>"
	return
    }

    ## endTable - end a TABLE element

    HtmlBuilder instproc endTable {} {
	my addStringDecr {</TABLE>}
	return
    }

    ## startTableRow - start a TR element
    ## Optional arguments:
    ##   Common HTML arguments
    HtmlBuilder instproc startTableRow {args} {
	set attributes [HtmlBuilder parseArguments $args [list "VALIGN"] [list]]
	my addStringIncr "<TR$attributes>"
	return
    }

    ## endTableRow - end a TR element

    HtmlBuilder instproc endTableRow {} {
	my addStringDecr {</TR>}
	return
    }

    ## startTableCell - start a TD element
    ## Optional arguments:
    ##   -colspan number
    ##   -rowspan number
    ##   -align left|center|right|justify|char
    ##   -valign top|middle|bottom|baseline
    ##   -bgcolor
    ##   -width
    ##   Common HTML arguments

    HtmlBuilder instproc startTableCell {args} {
	set attributes [HtmlBuilder parseArguments $args \
			    [list "COLSPAN" "ROWSPAN" "ALIGN" "VALIGN" \
				 "BGCOLOR" "WIDTH"] [list]]
	my addStringIncr "<TD$attributes>"
	return
    }

    ## endTableCell - end a TD element

    HtmlBuilder instproc endTableCell {} {
	my addStringDecr {</TD>}
	return
    }

    #
    # add a simple table cell which just contains a string
    #
    HtmlBuilder instproc addTableCell {{string ""} args} {
	eval my startTableCell $args
	my addString $string
	my endTableCell
    }

    ## startTableHeaderCell - start a TH element
    ## Optional arguments:
    ##   -colspan number
    ##   -rowspan number
    ##   -align left|center|right|justify|char
    ##   -valign top|middle|bottom|baseline
    ##   Common HTML arguments

    HtmlBuilder instproc startTableHeaderCell {args} {
	set attributes [HtmlBuilder parseArguments $args \
			    [list "COLSPAN" "ROWSPAN" "ALIGN" "VALIGN"] [list]]
	my addStringIncr "<TH$attributes>"
	return
    }

    ## endTableHeaderCell - end a TH element

    HtmlBuilder instproc endTableHeaderCell {} {
	my addStringDecr {</TH>}
	return
    }

    ## startForm - start a FORM element
    ## Required arguments:
    ##   -action URI
    ## Optional arguments:
    ##   -method get|post
    ##   Common HTML arguments

    HtmlBuilder instproc startForm {args} {
	set attributes [HtmlBuilder parseArguments $args \
			    [list "ACTION" "METHOD" "ENCTYPE"] [list]]
	my addStringIncr "<FORM$attributes>"
	return
    }

    ## endForm - end a FORM element

    HtmlBuilder instproc endForm {} {
	my addStringDecr {</FORM>}
	return
    }

    ## addInput - add in INPUT element
    ## Required arguments:
    ##   -type <input type>
    ##   -name <control name>
    ## Optional arguments:
    ##   -value <initial value>
    ##   -size <width of input, in pixels of characters>
    ##   -maxlength <max number of characters for text input>
    ##   -checked
    ##   Common HTML arguments
    
    HtmlBuilder instproc addInput {args} {
	set attributes [HtmlBuilder parseArguments $args \
			    [list "TYPE" "NAME" "VALUE" "SIZE" "MAXLENGTH"] \
			    [list "CHECKED"]]
	my addString "<INPUT$attributes>"
	return
    }

    ## addTextArea - start a TEXTAREA element
    ## First parameter: value - Default value of the text area
    ## Required arguments:
    ##   -rows <number of rows>
    ##   -cols <number of columns>
    ## Optional arguments:
    ##   -name <control name>
    ##   Common HTML Arguments

    HtmlBuilder instproc addTextArea {value args} {
	set attributes [HtmlBuilder parseArguments $args \
			    [list "ROWS" "COLS" "NAME"] [list]]
	my addString "<TEXTAREA$attributes>$value</TEXTAREA>"
	return
    }

    ## startOptionSelector - start a SELECT element
    ## Optional arguments:
    ##   -name <control name>
    ##   -size <number of visible items>
    ##   -multiple
    ##   Common HTML arguments

    HtmlBuilder instproc startOptionSelector {args} {
	set attributes [HtmlBuilder parseArguments $args \
			    [list "NAME" "SIZE"] [list "MULTIPLE"]]
	my addStringIncr "<SELECT$attributes>"
	return
    }    

    ## endOptionSelector - end a SELECT element

    HtmlBuilder instproc endOptionSelector {} {
	my addStringDecr "</SELECT>"
	return
    }

    ## startOption - start an OPTION element
    ## Optional arguments:
    ##   -value <value of option>
    ##   -selected
    ##   Common HTML arguments

    HtmlBuilder instproc startOption {args} {
	set attributes [HtmlBuilder parseArguments $args \
			    [list "VALUE"] [list "SELECTED"]]
	my addStringIncr "<OPTION$attributes>"
	return
    }

    ## endOption - end an OPTION element

    HtmlBuilder instproc endOption {} {
	my addStringDecr "</OPTION>"
	return
    }

    ## addImage - add an IMG element
    ## Required arguments:
    ##   -src <url>
    ##   -alt <alternate text>
    ##   -align <alignment> (deprecated in HTML 4.0)
    ## Optional arguments:
    ##   Common HTML arguments

    HtmlBuilder instproc addImage {args} {
	set attributes [HtmlBuilder parseArguments $args \
			    [list "SRC" "ALT" "ALIGN"] [list]]
	my addString "<IMG$attributes>"
	return
    }

    ## startBlock - start a DIV element (a generic block-level container)
    ## Optional arguments:
    ##   Common HTML attributes

    HtmlBuilder instproc startBlock {args} {
	set attributes [HtmlBuilder parseArguments $args [list] [list]]
	my addStringIncr "<DIV$attributes>"
	return
    }

    ## endBlock - end a DIV element

    HtmlBuilder instproc endBlock {} {
	my addStringDecr "</DIV>"
	return
    }

    ## addHorizontalRule - add an HR element
    ## Optional arguments:
    ##   Common HTML arguments

    HtmlBuilder instproc addHorizontalRule {args} {
	set attributes [HtmlBuilder parseArguments $args [list] [list]]
	my addString "<HR$attributes>"
	return
    }

    namespace export HtmlBuilder
}

namespace import ::xotcl::htmllib::*