cassiopeia: init project

This is the beginning of a Rust re-implementation of the original ruby
scripts.  cassiopeia is a simple time tracking tool, that integrates
into the larger ecosystem of project management tools that I use to
organise my business.

apps/cassiopeia/Cargo.toml

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+[package]
+name = "cassiopeia"
+version = "0.1.0"
+authors = ["Mx Kookie <kookie@spacekookie.de>"]
+edition = "2018"
+
+[dependencies]
+chrono = "*"

apps/cassiopeia/src/file.rs

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+//! Parse the cassiopeia file format
+//!
+//! Each file is associated with a single project.  This way there is
+//! no need to associate session enries with multiple customers and
+//! projcets.  Currently there's also no way to cross-relate sessions
+//! between projects or clients, although the metadata in the header
+//! is available to do so in the future
+//!
+//! ## Structure
+//!
+//! `cassiopeia` files should use the `.cass` extension, although this
+//! implementation is not opinionated on that.
+//!
+//! A line starting with `;` is a comment and can be ignored.  A line
+//! can have a comment anywhere, which means that everything after it
+//! gets ignored.  There are no block comments.
+//!
+//! A regular statements has two parts: a key, and a value.  Available
+//! keys are:
+//!
+//! - HEADER
+//! - START
+//! - STOP
+//! - FINISH
+//!
+//! A file has to have at least one `HEADER` key, containing a certain
+//! number of fields to be considered valid.  The required number of
+//! fields may vary between versions.
+//!
+//! ### HEADER
+//!
+//! `cassiopeia` in princpile only needs a single value to parse a
+//! file, which is `version`.  It is however recommended to add
+//! additional metadata to allow future processing into clients and
+//! cross-referencing projects.  Importantly: header keys that are not
+//! expected will be ignored.
+//!
+//! The general header format is a comma-separated list with a key
+//! value pair, separated by an equals sign.  You can use spaces in
+//! both keys and values without having to escape them or use special
+//! quotes.  Leading and trailing spaces will be removed.
+//!
+//! ```
+//! HEADER version=0.0.0,location=Berlin
+//! HEADER work schedule=mon tue wed
+//! ```
+//!
+//! When re-writing the file format, known/ accepted keys should go
+//! first.  All other unknown keys will be printed alphabetically at
+//! the end.  This way it's possible for an outdated implementation to
+//! pass through unknown keys, or users to add their own keys.
+
+use chrono::{DateTime, Utc};
+use std::{fs::File, io::Read, path::Path};
+
+/// A cassiopeia file that has been successfully parsed
+pub struct TimeFile {
+    path: PathBuf,
+    content: Vec<Statement>,
+}
+
+impl TimeFile {
+    /// Open an existing `.cass` file on disk.  Panics!
+    pub fn open(p: impl Into<Path>) -> Self {
+        let mut f = File::open(p).unwrap();
+        let mut cont = String::new();
+        f.read_to_string(&mut cont).unwrap();
+    }
+}
+
+/// A statement in a `.cass` line
+///
+/// While the whole file get's re-written on every run to update
+/// version numbers and header values, the structure of the file is
+/// preserved.
+pub enum Statement {
+    /// A blank line
+    Blank,
+    /// A comment line that is echo-ed back out
+    Comment(String),
+    /// Header value
+    Header(Vec<HeaderVal>),
+    /// A session start value
+    Start(DateTime<Utc>),
+    /// A session stop value
+    Stop(DateTime<Utc>),
+    /// A project finish value
+    Finish(DateTime<Utc>),
+}
+
+/// A set of header value
+pub struct HeaderVal {
+    /// Header key
+    key: String,
+    /// Header value
+    val: String,
+}
+
+impl HeaderVal {
+    fn new<S: Into<String>>(key: S, val: S) -> Self {
+        Self {
+            key: key.into(),
+            val: val.into(),
+        }
+    }
+
+    /// Test if a header value is known to this implementation
+    fn known(&self) -> bool {
+        match self.key {
+            "version" => true,
+            _ => false,
+        }
+    }
+}
+
+/// A builder for cass files
+#[cfg(tests)]
+struct FileBuilder {
+    acc: Vec<Statement>,
+}
+
+impl FileBuilder {
+    fn new() -> Self {
+        Self { acc: vec![] }
+    }
+
+    fn header(mut self, data: Vec<(&str, &str)>) -> Self {
+        self.acc.push(Statement::Header(
+            data.into_iter()
+                .map(|(key, val)| HeaderVal::new(key, val))
+                .collect(),
+        ));
+
+        self
+    }
+
+    fn build(self) -> String {
+        format!(";; This file was generated by cassiopeia (reference)\n{}", self.acc.into_iter().map(|s| s.render()).collect::<Vec<_>().join("\n"))
+    }
+}
+
+#[test]
+fn empty_file() {
+    let fb = FileBuilder::new().header(vec![("version", "0.3.0"), ("project", "testing")]);
+}

apps/cassiopeia/src/main.rs

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+fn main() {
+    println!("Hello, world!");
+}