-- ANTI-CAPITALIST SOFTWARE LICENSE (v 1.4)
-- 
--  marigold-cgi Copyright (c) 2022 Kate Swanson
-- 
-- This is anti-capitalist software, released for free use by individuals and 
-- organizations that do not operate by capitalist principles.
-- 
-- Permission is hereby granted, free of charge, to any person or organization (
-- the "User") obtaining a copy of this software and associated documentation 
-- files (the "Software"), to use, copy, modify, merge, distribute, and/or sell 
-- copies of the Software, subject to the following conditions:
-- 
-- 1. The above copyright notice and this permission notice shall be included in 
-- all copies or modified versions of the Software.
-- 
-- 2. The User is one of the following:
-- 	a. An individual person, laboring for themselves
-- 	b. A non-profit organization
-- 	c. An educational institution
-- 	d. An organization that seeks shared profit for all of its members, and allows 
-- 	   non-members to set the cost of their labor
-- 
-- 3. If the User is an organization with owners, then all owners are workers and 
--    all workers are owners with equal equity and/or equal vote.
-- 
-- 4. If the User is an organization, then the User is not law enforcement or 
--    military, or working for or under either.
-- 
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT EXPRESS OR IMPLIED WARRANTY OF ANY 
-- KIND, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS 
-- FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE 
-- LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 
-- CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
-- SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


local marigold = {}

marigold.h = function(tag_type, content, tbl)
	if type(content) == 'table' and tbl == nil then
		tbl = content
		content = ''
	end

	if content == nil then
		tbl = {}
		content = ''
	end

	local tag = {}
	tag.tag = tag_type
	tag.content = content
	tag.attributes = {}
	tag.children = {}

	if tbl then
		-- add attributes
		for k, v in pairs(tbl) do
			if type(k) == 'string' then
				tag.attributes[k] = v
			end
		end
		-- add children
		for _, child in ipairs(tbl) do
			table.insert(tag.children, child)
		end
	end
	return tag
end


local function render_internal(tbl, indent_level)
	indent_level = indent_level or 0
	local indent = string.rep('\t', indent_level)

	-- generate attribute strings
	local attributes = {}
	for k, v in pairs(tbl.attributes) do
		table.insert(attributes, string.format(' %s="%s"', k, v))
	end
	if test then
		-- sort alphabetically for well-defined testing
		table.sort(attributes)
	end
	local a = ''
	for _, attrib in ipairs(attributes) do
		a = a .. attrib
	end

	local open = string.format('<%s%s>', tbl.tag, a)
	local close = string.format('</%s>', tbl.tag)

	if #tbl.children == 0 then
		return string.format('%s%s%s%s', indent, open, tbl.content, close)
	end

	local children = ''
	for _, child in ipairs(tbl.children) do
		children = children .. render_internal(child, indent_level+1) .. '\n'
	end

	return string.format('%s%s%s\n%s%s%s',
		indent, open, tbl.content,
		children,
		indent, close)
end
marigold.prerender = render_internal

marigold.render = function(tbl)
	local str = render_internal(tbl, 0)
	return '<?xml version="1.0" encoding="UTF-8" standalone="no"?>\n' .. str
end


-- built-in svg types

local function set(tbl)
	local s = {}
	for _, v in ipairs(tbl) do
		s[v] = true
	end
	return s
end

local function validate(tagname, valid, tbl)
	local valid_set = set(valid)
	-- inject the core svg attributes
	valid_set.id = true
	valid_set.tabindex = true
	valid_set.lang = true
	valid_set['xml:space'] = true
	valid_set.class = true
	valid_set.style = true
	for k in pairs(tbl) do
		if not valid_set[k] then return string.format(
			"ERROR: attempted to set invalid attribute '%s' on tag of type %s",
			k, tagname
		) end
	end
	return nil
end

local function maketag(tag, content, tbl, valid)
	local t = marigold.h(tag, content, tbl)
	local err = validate(tag, valid, t.attributes)
	if err then return nil, err end
	return t, nil
end


marigold.svg = function(tbl)
	local tbl = tbl or {}
	tbl.xmlns = 'http://www.w3.org/2000/svg'
	local tag, err = maketag('svg', '', tbl, { 'xmlns', 'viewBox', 'width', 'height' })
	if err then error(err) end
	return tag
end


marigold.g = function(tbl)
	local tbl = tbl or {}
	local tag, err = maketag('g', '', tbl, { 'transform' })
	if err then error(err) end
	return tag
end


marigold.rect = function(tbl)
	local tag, err = maketag('rect', '', tbl, { 'x', 'y', 'width', 'height', 'rx', 'ry', 'transform', })
	if err then error(err) end
	return tag
end


marigold.text = function(content, tbl)
	local tag, err = maketag(
		'text', content, tbl, 
		{ 'lengthAdjust', 'x', 'y', 'dx', 'dy', 'rotate', 'textLength' }
	)
	if err then error(err) end
	return tag
end



return marigold