Small = {}

function Small.isDigit(ch)
	local n = string.byte(ch)
	if not n then return false end
	return n >= 48 and n <= 57
end

function Small.encodeString(raw, islua51)
	local out = '"' 

	for i = 1,#raw do
		local ch = raw:sub(i,i)

		local code = string.byte(ch)
		if ch == '\\' then
			out = out .. "\\\\"
		elseif ch == '"' then
			out = out .. '\\"'
		elseif ch == "\n" then
			out = out .. "\\n"
		elseif ch == '\r' then
			out = out .. "\\r"
		elseif ch == "\a" then
			out = out .. "\\a"
		elseif ch == "\b" then
			out = out .. "\\b"
		elseif ch == '\f' then
			out = out .. "\\f"
		elseif ch == "\t" then
			out = out .. "\\t"
		elseif code >= 32 and code <= 126 then
			out = out .. ch
		else
			local nextchar = raw:sub(i+1,i+1)
			if Small.isDigit(nextchar) then
				out = out .. "\\" .. DecEncode(code, 3)
			else
				out = out .. "\\" .. DecEncode(code, 1)
			end
		end
	end

	out = out .. '"'

	return out
end

function Small.encodeNumber(n)
	local num = ''
	local isneg = false

	if n < 0 then
		n = n * -1
		isneg = true;
	end

	local whole = math.floor(n)

	if whole == 0 then
		num = num .. '0'
	end

	while whole > 0 do
		local digit = whole % 10
		num = string.char(string.byte'0' + digit) .. num

		whole = math.floor(whole / 10)
	end

	local dec = n % 1

	if dec > 0 then
		num = num .. "."

		while dec > 0 do
			-- aw nah
			dec = dec * 10

			local digit = math.floor(dec)

			num = num .. string.char(string.byte'0' + digit)

			dec = dec % 1
		end
	end

	if isneg then
		num = '-' .. num
	end

	return num
end

function Small.convertBinaryOperator(lakeop, spacer)
	if lakeop == "+" then
		return "+"
	elseif lakeop == "-" then
		return "-"
	elseif lakeop == "*" then
		return "*"
	elseif lakeop == "/" then
		return "/"
	elseif lakeop == "%" then
		return "%"
	elseif lakeop == "^" then
		return "^"
	elseif lakeop == ".." then
		return ".."
	elseif lakeop == "<" then
		return "<"
	elseif lakeop == ">" then
		return ">"
	elseif lakeop == "<=" then
		return "<="
	elseif lakeop == ">=" then
		return ">="
	elseif lakeop == "!=" then
		return "~="
	elseif lakeop == "==" then
		return "=="
	elseif lakeop == "&&" then
		return spacer and ' and ' or "and"
	elseif lakeop == "||" then
		return spacer and ' or ' or "or"
	end
end

function Small.convertUnaryOperator(op)
	if op == "#" then
		return "#"
	elseif op == "-" then
		return "-"
	elseif op == "!" then
		return "not"
	end
end

function Small.output(outp, ast)
	Small.outputStatement(outp, ast)
end

---@param outp Output
---@param node Node
function Small.outputStatement(outp, node, noblock)
	if node.kind == "Program" then
		outp:appendLine("do ", '')

		for i = 1,#node.content do
			local stmt = node.content[i]

			Small.outputStatement(outp, stmt)
		end

		outp:appendLine("end;", '')
	elseif node.kind == "VariableDeclaration" then
		outp:appendLine("local ", '')
		local varnames = node.content[1]

		for i = 1,#varnames do
			local vname = varnames[i]

			outp:appendLine(vname[1], '')

			if i ~= #varnames then
				outp:appendLine(",", '')
			end
		end

		local values = node.content[2]
		if #values > 0 then
			outp:appendLine("=", '')

			for i = 1,#values do
				local val = values[i]

				Small.outputExpression(outp, val, false)

				if i ~= #values then
					outp:appendLine(",", '')
				end
			end
		end

		outp:appendLine(";", '')
	elseif node.kind == "Block" then
		if not noblock then
			outp:appendLine("do ", '')
		end

		for i = 1,#node.content do
			local stmt = node.content[i]

			Small.outputStatement(outp, stmt, #node.content == 1)
		end

		if not noblock then
			outp:appendLine("end;", '')
		end
	elseif node.kind == "IfStatement" then
		outp:appendLine("if ", '')

		Small.outputExpression(outp, node.content[1][1][1])

		outp:appendLine("then ", '')

		Small.outputStatement(outp, node.content[1][1][2], true)

		for i = 2, #node.content[1] do
			local item = node.content[1][i]
			-- print(item, item[1], item[2])
			outp:appendLine("elseif ", '')

			Small.outputExpression(outp,item[1]);

			outp:appendLine("then ", '')

			Small.outputStatement(outp,item[2], true);
		end

		if node.content[2] then
			outp:appendLine("else ", '')

			Small.outputStatement(outp, node.content[2], true)
		end

		outp:appendLine("end;", '')
	elseif node.kind == "FunctionDeclaration" then
		outp:appendLine("function ", '')
		
		Small.outputFunctionName(outp, node.content[1]);

		outp:appendLine("(", '')

		for i = 1,#node.content[2] do
			local part = node.content[2][i]

			outp:appendLine(part, '')

			if i ~= #node.content[2] then
				outp:appendLine(",", '')
			end
		end

		outp:appendLine(")", '')

		Small.outputStatement(outp, node.content[3], true)

		outp:appendLine("end;", '')
	elseif node.kind == "LocalFunctionDeclaration" then
		outp:appendLine("local function ", '')
		
		outp:appendLine(node.content[1].content, '');

		outp:appendLine("(", '')

		for i = 1,#node.content[2] do
			local part = node.content[2][i]

			outp:appendLine(part, '')

			if i ~= #node.content[2] then
				outp:appendLine(",", '')
			end
		end

		outp:appendLine(")", '')

		Small.outputStatement(outp, node.content[3], true)

		outp:appendLine("end;", '')
	elseif node.kind == "Return" then
		if #node.content > 0 then
			outp:appendLine("return ", '')
		else
			outp:appendLine('return', '')
		end

		for i = 1,#node.content do
			local expr = node.content[i]

			Small.outputExpression(outp, expr, false)

			if i ~= #node.content then
				outp:appendLine(",", '')
			end
		end

		outp:appendLine(";", '')
	elseif node.kind == "Assignment" then
		local vars = node.content[1]
		local vals = node.content[2]

		for i = 1,#vars do
			local var = vars[i]

			Small.outputVariable(outp, var)

			if i ~= #vars then
				outp:appendLine(",", '')
			end
		end

		outp:appendLine("=", '')

		for i = 1,#vals do
			local val = vals[i]

			Small.outputExpression(outp, val, false)

			if i ~= #vals then
				outp:appendLine(",", '')
			end
		end

		outp:appendLine(";", '')
	elseif node.kind == "Call" then
		outp:appendLine("(", '')
		Small.outputExpression(outp, node.content[1], false)
		outp:appendLine(")", '')

		outp:appendLine("(", '')
		
		local args = node.content[2]
		for i = 1,#args do
			local arg = args[i]

			Small.outputExpression(outp, arg, false)

			if i ~= #args then
				outp:appendLine(",", '')
			end
		end

		outp:appendLine(")", '')
		outp:appendLine(";", '')
	elseif node.kind == "MethodCall" then
		outp:appendLine("(", '')
		Small.outputExpression(outp, node.content[1], false)
		outp:appendLine("):", '')
		outp:appendLine(node.content[2], '')
		outp:appendLine("(", '')
		
		local args = node.content[3]
		for i = 1,#args do
			local arg = args[i]

			Small.outputExpression(outp, arg, false)

			if i ~= #args then
				outp:appendLine(",", '')
			end
		end

		outp:appendLine(")", '')
		outp:appendLine(";", '')
	elseif node.kind == "While" then
		outp:appendLine("while ", '')

		Small.outputExpression(outp, node.content[1])

		outp:appendLine("do ", '')

		Small.outputStatement(outp, node.content[2], true)

		outp:appendLine("end;", '')
	elseif node.kind == "For" then
		outp:appendLine("do ", '')
		Small.outputStatement(outp,node.content[1]);

		outp:appendLine("while ", '')
		Small.outputExpression(outp,node.content[2]);
		outp:appendLine("do ", '')

		outp:appendLine("do ", '')
		Small.outputStatement(outp,node.content[4], true);
		outp:appendLine("end;", '')

		Small.outputStatement(outp,node.content[3], true);

		outp:appendLine("end;", '')

		outp:appendLine("end;", '')
	elseif node.kind == "OperatorAssignment" then
		local lake_op = node.content[2]
		local op = Small.convertBinaryOperator(lake_op, true)

		local lhs = node.content[1]
		local rhs = node.content[3]

		if lhs.kind == "Variable" then
			local varname = lhs.content

			outp:appendLine(varname, '')
			outp:appendLine('=', '')
			outp:appendLine(varname, '')
			outp:appendLine(op, '')
			outp:appendLine('(', '')
			Small.outputExpression(outp, rhs, false)
			outp:appendLine(');', '')
		elseif lhs.kind == "Field" then
			outp:appendLine('do ', '')

			outp:appendLine('local _lake_oat=', '')
			Small.outputExpression(outp, lhs.content[1], false)
			outp:appendLine(';', '');

			outp:appendLine('_lake_oat.', '')
			outp:appendLine(lhs.content[2], '')

			outp:appendLine('=', '')

			outp:appendLine('_lake_oat.', '')
			outp:appendLine(lhs.content[2], '')
			outp:appendLine(op, '')
			outp:appendLine('(', '')
			Small.outputExpression(outp, rhs, false)
			outp:appendLine(');', '')

			outp:appendLine('end;', '')
		elseif lhs.kind == "Index" then
			outp:appendLine('do ', '')

			outp:appendLine('local _lake_oat=', '')
			Small.outputExpression(outp, lhs.content[1], false)
			outp:appendLine(';', '');

			outp:appendLine('_lake_oat[', '')
			Small.outputExpression(outp, lhs.content[2], false)
			outp:appendLine(']', '')

			outp:appendLine('=', '')

			outp:appendLine('_lake_oat[', '')
			Small.outputExpression(outp, lhs.content[2], false)
			outp:appendLine(']', '')
			outp:appendLine(op, '')
			outp:appendLine('(', '')
			Small.outputExpression(outp, rhs, false)
			outp:appendLine(');', '')

			outp:appendLine('end;', '')
		end
	elseif node.kind == "Break" then
		outp:appendLine('break;', '')
	elseif node.kind == "Foreach" then
		outp:appendLine("for ", '')

		local varlist,exprlist,block = node.content[1],node.content[2],node.content[3]

		for i = 1,#varlist do
			outp:appendLine(varlist[i], '')
			if i ~= #varlist then
				outp:appendLine(',', '')
			end
		end

		outp:appendLine(" in ", '')

		for i = 1,#exprlist do
			Small.outputExpression(outp, exprlist[i], i == #exprlist)

			if i ~= #exprlist then
				outp:appendLine(",", '')
			end
		end

		outp:appendLine('do ', '')

		Small.outputStatement(outp, block, true);

		outp:appendLine('end;', '')
	end
end

---@param outp Output
---@param node Node
function Small.outputExpression(outp, node, needsp)
	if needsp == nil then needsp = true end
	if node.kind == "StringLiteral" then
		local lakestr = node.content

		local raw = Lower.decodeString(lakestr)

		local enc = Small.encodeString(raw, outp.target == "lua51")

		outp:appendLine(enc, '')
	elseif node.kind == "ParenthesizedExpression" then
		outp:appendLine("(", '')
		Small.outputExpression(outp, node.content, false)
		outp:appendLine(")", '')
	elseif node.kind == "NumberLiteral" then
		local lakenum = node.content

		local raw = Lower.decodeNumber(lakenum)

		-- print(raw, type(raw))

		local enc = Small.encodeNumber(raw)

		outp:appendLine(enc, '')
		if needsp then
			outp:appendLine(' ', '')
		end
	elseif node.kind == "TableLiteral" then
		outp:appendLine('{', '')
		local list_part = node.content[1]
		local table_part = node.content[2]

		for i = 1,#list_part do
			local item = list_part[i]

			Small.outputExpression(outp, item, false);

			if (#table_part > 0) or (i < #list_part) then
				outp:appendLine(',', '')
			end
		end

		for i = 1,#table_part do
			local item = table_part[i]

			outp:appendLine('[', '')
			Small.outputExpression(outp, item[1], false)
			outp:appendLine(']', '')
			outp:appendLine('=', '')
			Small.outputExpression(outp, item[2], false)
			if (i < #table_part) then
				outp:appendLine(',', '')
			end
		end
		outp:appendLine('}', '')
	elseif node.kind == "LambdaFunctionLiteral" then
		outp:appendLine('function(', '')
		
		for i = 1,#node.content[1] do
			local part = node.content[1][i]

			outp:appendLine(part, '')

			if i ~= #node.content[1] then
				outp:appendLine(",", '')
			end
		end

		outp:appendLine(")", '')

		Small.outputStatement(outp, node.content[2], true)

		outp:appendLine("end", '')
		if needsp then
			outp:appendLine(' ', '')
		end
	elseif node.kind == "BinaryOperator" then
		local op = node.content[1]
		local lhs = node.content[2]
		local rhs = node.content[3]

		outp:appendLine("((", '')

		Small.outputExpression(outp,lhs, false)

		outp:appendLine(")", '')

		local luaop = Small.convertBinaryOperator(op)

		outp:appendLine(luaop, '')

		outp:appendLine("(", '')

		Small.outputExpression(outp,rhs,false)

		outp:appendLine("))", '')
	elseif node.kind == "UnaryOperator" then
		local op = node.content[1]
		local val = node.content[2]

		outp:appendLine("(", '')

		local luaop = Small.convertUnaryOperator(op)
		outp:appendLine(luaop, '')


		outp:appendLine("(", '')

		Small.outputExpression(outp,val,false)

		outp:appendLine("))", '')
	elseif node.kind == "Field" then
		local left = node.content[1]
		local right = node.content[2]

		outp:appendLine("(", '')
		Small.outputExpression(outp, left, false)
		outp:appendLine(").", '')
		outp:appendLine(right, '')
		if needsp then
			outp:appendLine(' ', '')
		end
	elseif node.kind == "Index" then
		local left = node.content[1]
		local right = node.content[2]

		outp:appendLine("(", '')
		Small.outputExpression(outp, left, false)
		outp:appendLine(")", '')
		outp:appendLine("[", '')
		Small.outputExpression(outp, right, false)
		outp:appendLine("]", '')
	elseif node.kind == "Variable" then
		outp:appendLine(node.content, '')
		if needsp then
			outp:appendLine(' ', '')
		end
	elseif node.kind == "BooleanLiteral" then
		outp:appendLine(node.content, '')
		if needsp then
			outp:appendLine(' ', '')
		end
	elseif node.kind == "NullLiteral" then
		outp:appendLine("nil", '')
		if needsp then
			outp:appendLine(' ', '')
		end
	elseif node.kind == "Call" then
		outp:appendLine("(", '')
		Small.outputExpression(outp, node.content[1], false)
		outp:appendLine(")", '')

		outp:appendLine("(", '')
		
		local args = node.content[2]
		for i = 1,#args do
			local arg = args[i]

			Small.outputExpression(outp, arg, false)

			if i ~= #args then
				outp:appendLine(",", '')
			end
		end

		outp:appendLine(")", '')
	elseif node.kind == "MethodCall" then
		outp:appendLine("(", '')
		Small.outputExpression(outp, node.content[1], false)
		outp:appendLine("):", '')
		outp:appendLine(node.content[2], '')
		outp:appendLine("(", '')
		
		local args = node.content[3]
		for i = 1,#args do
			local arg = args[i]

			Small.outputExpression(outp, arg, false)

			if i ~= #args then
				outp:appendLine(",", '')
			end
		end

		outp:appendLine(")", '')
	end
end

---@param outp Output
---@param node Node
function Small.outputFunctionName(outp, node)
	if node.kind == "Field" then
		local left = node.content[1]
		local right = node.content[2]

		Small.outputFunctionName(outp, left)
		outp:appendLine(".", '')
		outp:appendLine(right, '')
	elseif node.kind == "Index" then
		local left = node.content[1]
		local right = node.content[2]

		Small.outputFunctionName(outp, left)
		outp:appendLine("[", '')
		Small.outputExpression(outp, right, false)
		outp:appendLine("]", '')
	elseif node.kind == "Variable" then
		outp:appendLine(node.content, '')
	elseif node.kind == "Method" then
		local left = node.content[1]
		local right = node.content[2]

		Small.outputFunctionName(outp, left)
		outp:appendLine(":", '')
		outp:appendLine(right, '')
	end
end

---@param outp Output
---@param node Node
function Small.outputVariable(outp, node)
	if node.kind == "Field" then
		local left = node.content[1]
		local right = node.content[2]

		Small.outputExpression(outp, left, false)
		outp:appendLine(".", '')
		outp:appendLine(right, '')
	elseif node.kind == "Index" then
		local left = node.content[1]
		local right = node.content[2]

		Small.outputExpression(outp, left, false)
		outp:appendLine("[", '')
		Small.outputExpression(outp, right, false)
		outp:appendLine("]", '')
	elseif node.kind == "Variable" then
		outp:appendLine(node.content, '')
	end
end

RegisterOutMethod("small", Small)