#!/usr/bin/env tclsh
package require tclgumbo
package require Tk
package require tksvg
package require Img

# TODO: This is still ugly, refactor into functions and namespaces?

text .t -yscrollcommand {.s set} -relief flat -font {Times 12} -wrap word -border 4
scrollbar .s -command {.t yview}
pack .s -side right -fill y
pack .t -side left -fill both -expand 1

set w .t

$w tag config title -elide true
$w tag config href -elide true
$w tag config script -elide true
$w tag config style -elide true
$w tag config a -foreground blue -underline 1
$w tag config strong -font {Times 12 bold}
$w tag config b -font {Times 12 bold}
$w tag config i -font {Times 12 italic}
$w tag config em -font {Times 12 italic}
$w tag config pre -font {Courier 12}
$w tag config code -font {Courier 12}
$w tag config h1 -font {Times 18}
$w tag config h2 -font {Times 18}
$w tag config ul -lmargin1 40 -lmargin2 40
$w tag config dd -lmargin1 40 -lmargin2 40
$w tag config p
$w tag bind a <Enter> "$w config -cursor hand2"
$w tag bind a <Leave> "$w config -cursor {}"
$w tag bind a <ButtonRelease-1> "click $w %x %y"

# TODO: Avoid globals
variable baseAddress

proc makeAddress {address} {
	global baseAddress
	if {1 == [regexp {^https?.*} $address]} {
		return "$address"
	} elseif {1 == [regexp {^/[^/].*} $address]} {
		return "[regsub {(https?://[^/]+)/.*} $baseAddress {\1}]$address"
	} elseif {1 == [regexp {^//.*} $address]} {
		return "https:$address"
	} else {
		return "$baseAddress$address"
	}
}

proc click {w x y} {
	global baseAddress
	set range [$w tag prevrange href [$w index @$x,$y]]
	set address [eval $w get $range]
	set result [exec browse -f viewhtml [makeAddress $address]]
	if {[llength $result] == 2} {
		displayPage $w [lindex $result 0] [lindex $result 1]
	}
}

proc displayNode {w node tagList} {
	set type [gumbo::node_get_type $node]
	if {$type == $gumbo::GUMBO_NODE_ELEMENT} {
		set tag [gumbo::element_get_tag_name $node]
		set attributes [gumbo::element_get_attributes $node]

		# TODO: This could be simplified in a way that allows for easy extension and won't end up in a long if-elseif-chain
		if {$tag == "a"} {
			$w insert end [lindex [array get $attributes] 1] [concat $tagList href]
		} elseif {$tag == "img"} {
			$w insert end "\n"
			set lattr [array get $attributes]
			set path [makeAddress [lindex $lattr [expr [lsearch -exact $lattr src] + 1]]]
			set localPath [lindex [split [exec phttp $path] { }] 2]
			image create photo $path -file $localPath
			$w image create end -image $path
			$w insert end "\n"
		}

		foreach child_node [gumbo::element_get_children $node] {
			displayNode $w $child_node [concat $tag $tagList]
		}

		# TODO: Handle margins and blocks better than this.
		if {$tag == "h1" || $tag == "h2" || $tag == "p"} {
			$w insert end "\n\n" {}
		} elseif {$tag == "pre" || $tag == "li" || $tag == "dt" || $tag == "ul" || $tag == "dd" || $tag == "dl" || $tag == "div" || $tag == "br"} {
			$w insert end "\n" {}
		}
	} elseif {$type == $gumbo::GUMBO_NODE_TEXT} {
		# TODO: This could be simplified.
		if {0 <= [lsearch $tagList pre]} {
			$w insert end [gumbo::text_get_text $node] $tagList
		} else {
			$w insert end [regsub -all {\s+} [gumbo::text_get_text $node] " "] $tagList
		}
	}
}

proc displayPage {w newBaseAddress filePath} {
	global baseAddress
	set baseAddress $newBaseAddress

	set file [open $filePath]
	set html [read $file]
	set output [gumbo::parse $html]
	close $file

	$w config -state normal
	$w delete 1.0 end

	displayNode $w [gumbo::output_get_root $output] [list]

	$w config -state disabled
	gumbo::destroy_output $output
}

displayPage $w [lindex $argv 1] [lindex $argv 0]