Requirements

• Users must authenticate themselves to view or edit data sources.
• Authentication mechanisms include LINE auth and OAuth using Google.
• A user can define multiple data sources such as "Electric Meter" or "Water Meter".
• Each "data source" has a name, optional description, and a series of data entries. Each data entry includes a date/time and a numerical value.
• A "data source" may include additional information to describe or differentiate the source, such as place name, address, PEA meter number, or a thumbnail photo.
• For each data source, an authorized user can input entrie(s) with a date/time and numerical value, such as electric meter reading.
• An authorized user can view and edit past data entries.
• The user who creates a data source can grant permission to other users to access and view/edit the data source's data.
• Log all access to the application.
• Log all input and editing of data values.
• Record or regularly export all logs to an external location in a way that prevents deletion of logs.

Platform Requirements

• Application has both a web-based and mobile interface.
• The initial mobile interface is a LINE MiniApp.
• The web application and database can be self-hosted for development and testing.
• The application and database can be deployed to a cloud service or VPS.
• Design and implementation should not be tightly coupled to vendor-specific technology to avoid vendor lock-in.

Data and Access Requirements

• A data source contains a series of numeric values with a date/timestamp. The numeric values may be integer (such as reading from a standard electric power meter) or decimal.
• A User can view data from only the data sources he owns or has been granted access to.
• A User can create or have access to multiple data sources.
• Each data source may be accessed by multiple Users.
• There may be optional data validators for data sources.
• A data source has descriptive information and may or may not be associated with a home address.

Aspirational Features (Nice to Have)

• Graph of data for a selected period.
• Sort and filter data, such as filter by date range.
• User can export data to a file or other device.
• Monitor and block suspicious or excessive use.
• Later versions will add an Android application, but this is not included in the initial implementation.