From 5502c6d320f05f43239fc8e2b2839eb3fd5d742a Mon Sep 17 00:00:00 2001
From: Mx Kookie <kookie@spacekookie.de>
Date: Fri, 11 Dec 2020 13:38:58 +0000
Subject: cassiopeia: implementing basic file parser

---
 apps/cassiopeia/src/format/parser.rs | 78 ++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 apps/cassiopeia/src/format/parser.rs

(limited to 'apps/cassiopeia/src/format/parser.rs')

diff --git a/apps/cassiopeia/src/format/parser.rs b/apps/cassiopeia/src/format/parser.rs
new file mode 100644
index 000000000000..cc4b1b7c77df
--- /dev/null
+++ b/apps/cassiopeia/src/format/parser.rs
@@ -0,0 +1,78 @@
+//! cassiopeia parser
+//!
+//! Takes a lexer's token stream as an input, and outputs a fully
+//! parsed time file.
+
+use crate::format::{LineLexer, LineToken, Token};
+use chrono::{DateTime, FixedOffset as Offset};
+use logos::Lexer;
+use std::collections::BTreeMap;
+use std::iter::Iterator;
+
+/// A type-parsed line in a time file
+#[derive(Debug)]
+pub enum LineCfg {
+    /// A header line with a set of keys and values
+    Header(BTreeMap<String, String>),
+    /// A session start line with a date and time
+    Start(Option<DateTime<Offset>>),
+    /// A session stop line with a date and time
+    Stop(Option<DateTime<Offset>>),
+    /// An invoice line with a date
+    Invoice(Option<DateTime<Offset>>),
+    /// An empty line
+    Empty,
+    /// A temporary value that is invalid
+    #[doc(hidden)]
+    Ignore,
+}
+
+impl LineCfg {
+    pub(crate) fn valid(&self) -> bool {
+        match self {
+            LineCfg::Ignore => false,
+            _ => true,
+        }
+    }
+}
+
+pub(crate) fn parse<'l>(lex: LineLexer<'l>) -> LineCfg {
+    use LineCfg::*;
+    use Token as T;
+
+    #[cfg_attr(rustfmt, rustfmt_skip)]
+    lex.get_all().into_iter().fold(Ignore, |cfg, tok| match (cfg, tok) {
+        // If the first token is a comment, we ignore it
+        (Ignore, LineToken { tt: T::Comment, .. }, ) => Ignore,
+        // If the first token is a keyword, we wait for more data
+        (Ignore, LineToken { tt: T::Header, .. }) => Header(Default::default()),
+        (Ignore, LineToken { tt: T::Start, .. }) => Start(None),
+        (Ignore, LineToken { tt: T::Stop, .. }) => Stop(None),
+        (Ignore, LineToken { tt: T::Invoice, .. }) => Invoice(None),
+
+        // If the first token _was_ a keyword, fill in the data
+        (Header(map), LineToken { tt: T::HeaderData, slice }) => Header(append_data(map, slice)),
+        (Start(_), LineToken { tt: T::Date, slice }) => Start(parse_date(slice)),
+        (Stop(_), LineToken { tt: T::Date, slice }) => Stop(parse_date(slice)),
+        (Invoice(_), LineToken { tt: T::Date, slice }) => Invoice(parse_date(slice)),
+
+        // Pass empty lines through,
+        (Empty, _) => Empty,
+
+        // Ignore everything else (which will be filtered)
+        _ => Ignore,
+    })
+}
+
+fn append_data(mut map: BTreeMap<String, String>, slice: &str) -> BTreeMap<String, String> {
+    let split = slice.split("=").collect::<Vec<_>>();
+    map.insert(split[0].into(), split[1].into());
+    map
+}
+
+fn parse_date(slice: &str) -> Option<DateTime<Offset>> {
+    Some(
+        DateTime::parse_from_str(slice, "%Y-%m-%d %H:%M:%S%:z")
+            .expect("Failed to parse date; invalid format!"),
+    )
+}
-- 
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