Moonshark/modules/json/json.lua

-- modules/json.lua - High-performance JSON module using Go functions

local json = {}

-- Use the fast Go JSON encoder/decoder
function json.encode(value)
	return moonshark.json_encode(value)
end

function json.decode(str)
	local result, err = moonshark.json_decode(str)
	if result == nil and err then
		error("json_decode: " .. err)
	end
	return result
end

-- Pretty print JSON with indentation
function json.pretty(value, indent)
	indent = indent or 2
	local encoded = json.encode(value)
	local result = {}
	local depth = 0
	local in_string = false
	local escape_next = false
	
	for i = 1, #encoded do
		local char = encoded:sub(i, i)
		
		if escape_next then
			table.insert(result, char)
			escape_next = false
		elseif char == "\\" and in_string then
			table.insert(result, char)
			escape_next = true
		elseif char == '"' then
			table.insert(result, char)
			in_string = not in_string
		elseif not in_string then
			if char == "{" or char == "[" then
				table.insert(result, char)
				depth = depth + 1
				table.insert(result, "\n" .. string.rep(" ", depth * indent))
			elseif char == "}" or char == "]" then
				depth = depth - 1
				table.insert(result, "\n" .. string.rep(" ", depth * indent))
				table.insert(result, char)
			elseif char == "," then
				table.insert(result, char)
				table.insert(result, "\n" .. string.rep(" ", depth * indent))
			elseif char == ":" then
				table.insert(result, char .. " ")
			else
				table.insert(result, char)
			end
		else
			table.insert(result, char)
		end
	end
	
	return table.concat(result)
end

-- Load JSON from file
function json.load_file(filename)
	if not moonshark.file_exists(filename) then
		error("File not found: " .. filename)
	end
	
	local file = io.open(filename, "r")
	if not file then
		error("Cannot open file: " .. filename)
	end
	
	local content = file:read("*all")
	file:close()
	
	return json.decode(content)
end

-- Save data to JSON file
function json.save_file(filename, data, pretty)
	local content
	if pretty then
		content = json.pretty(data)
	else
		content = json.encode(data)
	end
	
	local file = io.open(filename, "w")
	if not file then
		error("Cannot write to file: " .. filename)
	end
	
	file:write(content)
	file:close()
end

-- Merge JSON objects
function json.merge(...)
	local result = {}
	for i = 1, select("#", ...) do
		local obj = select(i, ...)
		if type(obj) == "table" then
			for k, v in pairs(obj) do
				result[k] = v
			end
		end
	end
	return result
end

-- Extract values by JSONPath-like syntax (simplified)
function json.extract(data, path)
	local parts = moonshark.string_split(path, ".")
	local current = data
	
	for _, part in ipairs(parts) do
		if type(current) ~= "table" then
			return nil
		end
		
		-- Handle array indices [0], [1], etc.
		local array_match = part:match("^%[(%d+)%]$")
		if array_match then
			local index = tonumber(array_match) + 1 -- Lua is 1-indexed
			current = current[index]
		else
			current = current[part]
		end
		
		if current == nil then
			return nil
		end
	end
	
	return current
end

-- Validate JSON structure against schema (basic)
function json.validate(data, schema)
	local function validate_value(value, schema_value)
		local value_type = type(value)
		local schema_type = schema_value.type
		
		if schema_type and value_type ~= schema_type then
			return false, "Expected " .. schema_type .. ", got " .. value_type
		end
		
		if schema_type == "table" and schema_value.properties then
			for prop, prop_schema in pairs(schema_value.properties) do
				if schema_value.required and schema_value.required[prop] and value[prop] == nil then
					return false, "Missing required property: " .. prop
				end
				
				if value[prop] ~= nil then
					local valid, err = validate_value(value[prop], prop_schema)
					if not valid then
						return false, "Property " .. prop .. ": " .. err
					end
				end
			end
		end
		
		return true
	end
	
	return validate_value(data, schema)
end

return json