-- Copyright (C) 2021 Kim Alvefur

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

-- Based on

-- https://json-schema.org/draft/2020-12/json-schema-core.html

-- https://json-schema.org/draft/2020-12/json-schema-validation.html

-- http://spec.openapis.org/oas/v3.0.1#xmlObject

-- https://github.com/OAI/OpenAPI-Specification/issues/630 (text:true)

--

-- XML Object Extensions:

-- text to refer to the text content at the same time as attributes

-- x_name_is_value for enum fields where the <tag-name/> is the value

-- x_single_attribute for <tag attr="this"/>

--

-- TODO arrays

-- TODO pointers

-- TODO cleanup / refactor

--

local st = require "util.stanza";

local js = require "util.jsonschema"

local function toboolean ( s : string ) : boolean

	if s == "true" or s == "1" then

		return true

	elseif s == "false" or s == "0" then

		return false

	end

end

local function parse_object (schema : js.schema_t, s : st.stanza_t) : table

	local out : { string : any } = {}

	if schema.properties then

		for prop, propschema in pairs(schema.properties) do

			-- TODO factor out, if it's generic enough

			local name = prop

			local namespace = s.attr.xmlns;

			local prefix : string = nil

			local single_attribute : string

			local enums : { any }

			local proptype : js.schema_t.type_e

			if propschema is js.schema_t then

				proptype = propschema.type

			elseif propschema is js.schema_t.type_e then

				proptype = propschema

			end

			if propschema is js.schema_t and propschema.xml then

				if propschema.xml.name then

					name = propschema.xml.name

				end

				if propschema.xml.namespace then

					namespace = propschema.xml.namespace

				end

				if propschema.xml.prefix then

					prefix = propschema.xml.prefix

				end

				if propschema.xml.attribute then

				elseif propschema.xml.text then

					-- XXX Not yet in OpenAPI

				elseif propschema.xml.x_name_is_value then

					-- XXX Custom extension

				elseif propschema.xml.x_single_attribute then

					-- XXX Custom extension

					single_attribute = propschema.xml.x_single_attribute

				end

				if propschema["const"] then

					enums = { propschema["const"] }

				elseif propschema["enum"] then

					enums = propschema["enum"]

				end

			end

				local c : st.stanza_t

				if proptype == "boolean" then

					c = s:get_child(name, namespace);

				elseif enums and proptype == "string" then

					-- XXX O(n²) ?

					-- Probably better to flip the table and loop over :childtags(nil, ns), should be 2xO(n)

					-- BUT works first, optimize later

					for i = 1, #enums do

						c = s:get_child(enums[i] as string, namespace);

						if c then break end

					end

				else

					c = s:get_child(nil, namespace);

				end

				if c and proptype == "string" then

					out[prop] = c.name;

				elseif proptype == "boolean" and c then

					out[prop] = true;

				end

				local attr = name

				if prefix then

					attr = prefix .. ':' .. name

				elseif namespace ~= s.attr.xmlns then

					attr = namespace .. "\1" .. name

				end

				if proptype == "string" then

					out[prop] = s.attr[attr]

				elseif proptype == "integer" or proptype == "number" then

					-- TODO floor if integer ?

					out[prop] = tonumber(s.attr[attr])

				elseif proptype == "boolean" then

					out[prop] = toboolean(s.attr[attr])

				-- else TODO

				end

				if proptype == "string" then

					out[prop] = s:get_text()

				elseif proptype == "integer" or proptype == "number" then

					out[prop] = tonumber(s:get_text())

				end

				local c = s:get_child(name, namespace)

				local a = c and c.attr[single_attribute]

				if proptype == "string" then

					out[prop] = a

				elseif proptype == "integer" or proptype == "number" then

					out[prop] = tonumber(a)

				elseif proptype == "boolean" then

					out[prop] = toboolean(a)

				end

			else

				if proptype == "string" then

					out[prop] = s:get_child_text(name, namespace)

				elseif proptype == "integer" or proptype == "number" then

					out[prop] = tonumber(s:get_child_text(name, namespace))

				elseif proptype == "object" and propschema is js.schema_t then

					local c = s:get_child(name, namespace)

					if c then

						out[prop] = parse_object(propschema, c);

					end

				-- else TODO

				end

			end

		end

	end

	return out

end

local function parse (schema : js.schema_t, s : st.stanza_t) : table

	if schema.type == "object" then

		return parse_object(schema, s)

	end

end

local function unparse ( schema : js.schema_t, t : table, current_name : string, current_ns : string ) : st.stanza_t

	if schema.type == "object" then

		if schema.xml then

			if schema.xml.name then

				current_name = schema.xml.name

			end

			if schema.xml.namespace then

				current_ns = schema.xml.namespace

			end

			-- TODO prefix?

		end

		local out = st.stanza(current_name, { xmlns = current_ns })

		for prop, propschema in pairs(schema.properties) do

			local v = t[prop]

			if v ~= nil then

				local proptype : js.schema_t.type_e

				if propschema is js.schema_t then

					proptype = propschema.type

				elseif propschema is js.schema_t.type_e then

					proptype = propschema

				end

				local name = prop

				local namespace = current_ns

				local prefix : string = nil

				local single_attribute : string

				if propschema is js.schema_t and propschema.xml then

					if propschema.xml.name then

						name = propschema.xml.name

					end

					if propschema.xml.namespace then

						namespace = propschema.xml.namespace

					end

					if propschema.xml.prefix then

						prefix = propschema.xml.prefix

					end

					if propschema.xml.attribute then

					elseif propschema.xml.text then

					elseif propschema.xml.x_name_is_value then

					elseif propschema.xml.x_single_attribute then

						single_attribute = propschema.xml.x_single_attribute

					end

				end

					local attr = name

					if prefix then

						attr = prefix .. ':' .. name

					elseif namespace ~= current_ns then

						attr = namespace .. "\1" .. name

					end

					if proptype == "string" and v is string then

						out.attr[attr] = v

					elseif proptype == "number" and v is number then

						out.attr[attr] = string.format("%g", v)

					elseif proptype == "integer" and v is number then

						out.attr[attr] = string.format("%d", v)

					elseif proptype == "boolean" then

						out.attr[attr] = v and "1" or "0"

					end

					if v is string then

						out:text(v)

					end

					local propattr : { string : string } = {}

					if namespace ~= current_ns then

						propattr.xmlns = namespace

					end

					if proptype == "string" and v is string then

						propattr[single_attribute] = v

					elseif proptype == "number" and v is number then

						propattr[single_attribute] = string.format("%g", v)

					elseif proptype == "integer" and v is number then

						propattr[single_attribute] = string.format("%d", v)

					elseif proptype == "boolean" and v is boolean then

						propattr[single_attribute] = v and "1" or "0"

					end

					out:tag(name, propattr):up();

				else

					local propattr : { string : string }

					if namespace ~= current_ns then

						propattr = { xmlns = namespace }

					end

						if proptype == "string" and v is string then

							out:tag(v, propattr):up();

						elseif proptype == "boolean" and v == true then

							out:tag(name, propattr):up();

						end

					elseif proptype == "string" and v is string then

						out:text_tag(name, v, propattr)

					elseif proptype == "number" and v is number then

						out:text_tag(name, string.format("%g", v), propattr)

					elseif proptype == "integer" and v is number then

						out:text_tag(name, string.format("%d", v), propattr)

					elseif proptype == "boolean" and v is boolean then

						out:text_tag(name, v and "1" or "0", propattr)

					elseif proptype == "object" and propschema is js.schema_t and v is table then

						local c = unparse(propschema, v, name, namespace);

						if c then

							out:add_direct_child(c);

						end

					-- else TODO

					end

				end

			end

		end

		return out;

	end

end

return {

	parse = parse,

	unparse = unparse,

}