-- Dump a table to help develop other modules.

-- It is also possible to use mw.dumpObject() but the result from this

-- module is clearer and is close to valid Lua source.

-- The main purpose is to allow easy inspection of Wikidata items.

-- Preview the following in a sandbox to see entity Q833639 as a Lua table:

--   {{#invoke:dump|wikidata|Q833639}}

-- Preview the following to dump a built-in table:

--   {{#invoke:dump|testcase}}



local Collection  -- a table to hold items

Collection = {

	add = function (self, item)

		if item ~= nil then

			self.n = self.n + 1

			selfself.n = item

		end

	end,

	join = function (self, sep)

		return table.concat(self, sep)

	end,

	remove = function (self, pos)

		if self.n > 0 and (pos == nil or (0 < pos and pos <= self.n)) then

			self.n = self.n - 1

			return table.remove(self, pos)

		end

	end,

	sort = function (self, comp)

		table.sort(self, comp)

	end,

	new = function ()

		return setmetatable({n = 0}, Collection)

	end

}

Collection.__index = Collection



local function pre_block(text)

	-- Pre tags returned by a module do not act like wikitext <pre>...</pre>.

	return '<pre>\n' ..

		mw.text.nowiki(text) ..

		(text:sub(-1) == '\n' and '' or '\n') ..

		'</pre>\n'

end



local function make_tabstr(indent)

	-- Return a string to generate one level of indent.

	if indent == 'tab' then

		-- Tabs do not work well in a browser edit window, but can force them.

		return '\t'

	end

	indent = tonumber(indent)

	if not (type(indent) == 'number' and 1 <= indent and indent <= 32) then

		indent = 4

	end

	return string.rep(' ', indent)

end



local function _dumphtml(html, tabwidth)

	-- Return a pretty-text formatted dump of an html string.

	-- This assumes clean html, for example, tag "<table>" not "< table >".

	if type(html) ~= 'string' then

		return ''

	end

	local selfClosingTags = {  -- from mw.html.lua

		area = true,

		base = true,

		br = true,

		col = true,

		command = true,

		embed = true,

		hr = true,

		img = true,

		input = true,

		keygen = true,

		link = true,

		meta = true,

		param = true,

		source = true,

		track = true,

		wbr = true,

	}

	local tabstr = make_tabstr(tabwidth)

	local function indent_pad(depth, isfirst)

		-- Return a string with an indent to match depth.

		if depth > 0 then

			return '\n' .. string.rep(tabstr, depth)

		end

		return isfirst and '' or '\n'

	end

	local function extract(result, html, pos, len, depth, currenttag)

		-- Dump more of html into table result and return new pos.

		local has_child

		while pos <= len do

			local s, e = html:find('<[^<>]*>', pos)

			if s then

				if s > pos then

					table.insert(result, html:sub(pos, s-1))

				end

				if html:sub(s+1, s+1) == '/' then

					-- A closing tag.

					local tag = html:match('^([a-zA-Z0-9]+)>', s+2) or 'NOTAG'

					if tag == currenttag then

						local indent = has_child and indent_pad(depth - 1) or ''

						table.insert(result, indent .. '</' .. tag .. '>')

					else

						-- Should never happen.

						table.insert(result, '\n</' .. tag .. '>')

					end

					return e + 1

				end

				local tag = html:match('^[a-zA-Z0-9]+', s+1) or 'NOTAG'

				if html:sub(e-1, e-1) == '/' or selfClosingTagstag then

					-- A self-closing tag.

					table.insert(result, html:sub(s, e))

					pos = e + 1

				else

					-- An opening tag.

					table.insert(result, indent_pad(depth, pos == 1) .. html:sub(s, e))

					pos = extract(result, html, e+1, len, depth+1, tag)

					has_child = true

				end

			else

				table.insert(result, html:sub(pos))

				break

			end

		end

		return len + 1

	end

	local result = {}

	html = html:gsub('>%s+<', '><'):gsub('\n%s*', ' ')

	extract(result, html, 1, #html, 0)

	return pre_block(table.concat(result))

end



local function dumphtml(frame)

	local args = frame.args

	local pargs = frame:getParent().args

	local text = args1 or pargs1

	local indent = args.indent or pargs.indent

	return _dumphtml(text, indent)

end



local function quoted(str)

	return (string.format('%q', str):gsub('\\\n', '\\n'))

end



local function iterkeys(var, control)

	-- Return an iterator over the keys of var (which should be a table).

	-- The keys are sorted with numbered keys first, then other types.

	-- The iterator returns key, repr where key is the actual key, and

	-- repr is its representation: a number for the ipairs keys, or

	-- a string, including for number keys above the table length.

	if type(var) ~= 'table' then

		return function () return nil end

	end

	local nums = {}

	local results = Collection.new()

	for i, _ in ipairs(var) do

		numsi = true

		results:add({ i, i })

	end

	local keys = Collection.new()

	for k, _ in pairs(var) do

		if not numsk then

			keys:add(k)

		end

	end

	local autoname = control.autoname

	keys:sort(function (a, b)

			local ta, tb = type(a), type(b)

			if ta == tb then

				if ta == 'number' or ta == 'string' then

					return a < b

				end

				if ta == 'boolean' then

					return b and not a

				end

				return autoname(a) < autoname(b)

			end

			if ta == 'number' then

				return true

			elseif tb == 'number' then

				return false

			else

				return ta < tb

			end

		end)

	for _, k in ipairs(keys) do

		local repr

		local tk = type(k)

		if tk == 'number' then

			repr = '[' .. k .. ']'

		elseif tk == 'string' then

			if k:match('^[%a_][%w_]*$') then

				repr = k

			else

				repr = '[' .. quoted(k) .. ']'

			end

		elseif tk == 'boolean' then

			repr = '[' .. tostring(k) .. ']'

		else

			repr = autoname(k)

			control.neededrepr = true

		end

		results:add({ k, repr })

	end

	local last = 0

	return function ()

		if last < results.n then

			last = last + 1

			return unpack(resultslast])

		end

	end

end



local function vardump(var, vname, depth, control, self, parents)

	-- Update items in control with results from dumping a variable.

	local function put(value, options)

		options = options or {}

		local indent = options.indent or depth

		local comma = (options.kind == 'open' or indent == 0) and '' or ','

		control.items:add({

			key = (type(vname) == 'string' and options.kind ~= 'close') and vname or nil,

			value = value .. comma,

			depth = indent,

			note = options.note

		})

	end

	if var == nil then

		put('nil')

	elseif type(var) == 'string' then

		put(quoted(var))

	elseif type(var) == 'table' then

		local this = control.autoname(var)

		if depth >= control.limitdepth then

			put(this)

		elseif parents and parentsthis then

			control.neededthis = true

			if self == this then

				put(this, {note = 'self'})

				control.needed'self' = true

			else

				put(this, {note = 'repeat'})

				control.needed'repeat' = true

			end

		else

			parents = parents or {}

			parentsthis = true

			self = this

			put('{', {kind = 'open', note = this})

			local mt = getmetatable(var)

			if mt then

				vardump(mt, '__metatable', depth + 1, control, self, parents)

			end

			local maxsize = control.items.n + control.limititems

			for key, keyrep in iterkeys(var, control) do

				if control.items.n > maxsize then

					put('...more...')

					break

				end

				vardump(varkey], keyrep, depth + 1, control, self, parents)

			end

			put('}', { kind = 'close' })

		end

	elseif type(var) == 'boolean' or type(var) == 'number' then

		put(tostring(var))

	else  -- function (or userdata or thread)

		put(control.autoname(var))

	end

end



local function dumper(var, vname, tabwidth, wantraw, limititems, limitdepth)

	-- Return a string representing var in almost-correct Lua syntax.

	-- There is no newline at the end of the result.

	local onames = {}

	local tcounts = {}

	local function autoname(var)

		-- Return a string that is a unique name for var, given it is not

		-- a number or string.

		if not onamesvar then

			local name = type(var)

			tcountsname = (tcountsname or 0) + 1

			onamesvar = name .. '_' .. tcountsname

		end

		return onamesvar

	end

	local control = {

		autoname = autoname,

		limititems = limititems or 10000,

		limitdepth = limitdepth or 50,

		items = Collection.new(),

		needed = {},

	}

	vardump(var, tostring(vname or 'variable'), 0, control)

	local tabstr = make_tabstr(tabwidth)

	local lines = Collection.new()

	for i, v in ipairs(control.items) do

		local indent = string.rep(tabstr, v.depth)

		local note = v.note

		if note and control.needednote then

			note = '  -- ' .. note

		else

			note = ''

		end

		local k = v.key and (v.key .. ' = ') or ''

		lines:add(indent .. k .. v.value .. note)

	end

	local raw = lines:join('\n')

	return wantraw and raw or pre_block(raw)

end



local function dump_testcase(frame)

	local item

	if type(frame) == 'table' then

		item = frame.args1

	else

		item = frame

	end

	if item == 'G' or item == '_G' then

		return dumper(_G, '_G', frame.args.indent)

	end

	local fruit = { 'apple', 'banana', 0 = 'zero', [{'anon'}] = 'anon' }

	local testcase = {

		100 = 'one hundred',

		99 = 'ninety nine',

		0.5 = 'one half',

		-1 = 'negative one',

		'one',

		'two',

		' ' = 'space',

		'1 –◆— z' = 'unicode',

		alpha = 'aaa',

		beta = 'bbb',

		c = 123,

		data = {

			dumper = dumper,

			dumper = 'dumper',

			'three',

			'four',

			T = true,

			true = 'T',

			alpha2 = 'aaa2',

			beta2 = 'bbb2',

			F = false,

			false = 'F',

			c2 = 1234,

			data2 = {

				'five',

				'six',

				alpha3 = 'aaa3',

				beta3 = 'bbb3',

				c3 = 12345,

				fruit = fruit,

				fruit = 'fruit',

			},

		},

		z = 'zoo',

	}

	testcase.testcase = testcase

	testcase.data.me = testcase.data

	testcase.data.data2.me = testcase

	testcase.data.data2.fruit.back = testcase.data

	setmetatable(testcase.data, {

		__index = function (self, key) return type(key) == 'string' and #key or nil end,

		__tostring = function (self) return tostring(#self) end,

	})

	if item == 'return table' then

		return testcase

	end

	return dumper(testcase, 'testcase', frame.args.indent)

end



local function execute(frame)

	-- Return a dump of the result from executing {{#invoke:dump|execute|EXPRESSION}}.

	-- In general that is not possible in Scribunto so this has built-in code

	-- to parse some expressions of interest.

	-- The primary aim is to test the result of calling a Wikidata function

	-- while previewing an edit in an article.

	-- Examples of EXPRESSION:

	--   mw.wikibase.getEntityIdForCurrentPage()

	--   mw.wikibase.getBestStatements('Q868', 'P214')

	--   mw.wikibase.getBestStatements(Q868, P214)       -- also accepted

	--   mw.wikibase.getEntity():getDescription('de')

	--   mw.wikibase.getEntity('Q868'):getDescription('de')

	-- getEntityObject is an alias for getEntity.

	-- Using the following gives an "out of memory" error presumably because

	-- the result is a table with a metatable that dump repeatedly expands.

	--   mw.title.getCurrentTitle()

	local function params(ptext, first)

		local p = { first }

		for item in (ptext .. ','):gmatch('(%S.-)%s*,') do

			-- Remove any quotes around each parameter because it is already a string.

			local _, s = item:match([[^%s*(['"])(.*)%1%s*$]])

			table.insert(p, s or tonumber(item) or item)

		end

		return unpack(p)

	end

	local expression = frame.args1 or ''

	local text = expression:match('^%s*mw(%..-)%s*$')

	if not text then

		return 'Expression not recognized: "' .. expression .. '"'

	end

	-- Look for a supported expression of form 'mw.a.b(c):d.e(f)'.

	local entity

	local object = mw

	local item, ptext, rest = text:match('^%.wikibase%.(%w+)%s*%((.*)%):(.*)$')

	if item == 'getEntity' or item == 'getEntityObject' then

		entity = mw.wikibase.getEntity(params(ptext))

		if not entity then

			return 'No entity found for (' .. ptext .. ')'

		end

		object = entity

		text = '.' .. rest  -- treat ':' as '.'

	end

	local upto = 1

	for i1, item, i2 in text:gmatch('()%.(%w+)()') do

		if i1 == upto and type(object) == 'table' then

			object = objectitem

		else

			object = nil

		end

		if object == nil then

			return 'Invalid item "' .. item .. '"'

		end

		if type(object) == 'function' then

			if text:sub(i2, i2 + 1) == '()' then

				object = object()

				i2 = i2 + 2

			end

		end

		upto = i2

	end

	local parm = text:sub(upto):match('^%((.*)%)%s*$')

	if parm then

		object = object(params(parm, entity))

	end

	return dumper(object, expression)

end



local function dumpargs(frame)

	-- Return text dump of frame.args.

	-- {{#invoke:dump|args|<ref>Example</ref>}} → display ref strip marker

	local control = {

		autoname = function (var) return tostring(var) end,  -- should not be called since keys should be numbers or strings

	}

	local lines = Collection.new()

	for key, keyrep in iterkeys(frame.args, control) do

		lines:add(keyrep .. ' = <code>' .. mw.text.nowiki(frame.argskey]) .. '</code>')

	end

	return lines:join('<br>\n')

end



local function parameters(frame)

	-- Return text dump of args and parent args from frame.

	-- This is for debugging a module to show what parameters it received.

	local control = {

		autoname = function (var) return tostring(var) end,  -- should not be called since keys should be numbers or strings

	}

	local lines = Collection.new()

	lines:add('')

	for _, f in ipairs({ frame, frame:getParent() }) do

		lines:add('[[' .. f:getTitle() .. ']]')

		for key, keyrep in iterkeys(f.args, control) do

			lines:add('&nbsp;&nbsp;' .. mw.text.nowiki(keyrep .. '=' .. f.argskey]))

		end

	end

	lines:add('')

	return lines:join('<br>\n')

end



local function wikidata(frame)

	local item = frame.args1

	if item then

		local id = item:match('^%s*([PQ]%d+)%s*$')

		if id then

			local entity = mw.wikibase.getEntity(id)

			return dumper(entity, id, frame.args.indent)

		end

	end

	return 'Parameter should be a Wikidata identifier such as P2386 or Q833639'

end



local builtins = {

	-- Handle preview of wikitext like {{#invoke|dump|TEXT}}

	-- where TEXT is a built-in value that can be dumped.

	__index = function (self, key)

		local result

		local function caller()

			return result

		end

		if type(key) == 'string' then

			local title = key:match('^%s*[\'"]?(.*%.tab)[\'"]?%s*$')

			if title then

				-- Assume structured data from Commons at [[c:Data:<title>]].

				if title:match('^[Dd]ata:') then

					title = title:sub(6)

				end

				local data = mw.ext.data.get(title)  -- false if page does not exist

				result = dumper(data, '[[c:Data:' .. title .. ']]')

			end

		end

		result = result or ('UNKNOWN: ' .. tostring(key))

		return caller

	end

}



return setmetatable({

	args = dumpargs,

	_dump = dumper,

	_dumphtml = _dumphtml,

	dumphtml = dumphtml,

	execute = execute,

	parameters = parameters,

	testcase = dump_testcase,

	wikidata = wikidata,

}, builtins)