From 11399468e7df506199fe5b5d00d36e2e0cb5aef0 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Thu, 25 Nov 2021 01:23:50 +0100
Subject: [PATCH] Allow repetitions to start from last DONE

---
 src/files/commands.rs  | 10 +++++++++-
 src/files/format.rs    | 11 ++++++++++-
 src/files/grammar.pest |  3 ++-
 src/files/parse.rs     | 24 +++++++++++++++++++-----
 4 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/src/files/commands.rs b/src/files/commands.rs
index e132520..0e778f6 100644
--- a/src/files/commands.rs
+++ b/src/files/commands.rs
@@ -97,6 +97,14 @@ impl DeltaStep {
 #[derive(Debug)]
 pub struct Delta(pub Vec<DeltaStep>);
 
+#[derive(Debug)]
+pub struct Repeat {
+    /// Start at the date when the latest `DONE` was created instead of the
+    /// task's previous occurrence.
+    pub start_at_done: bool,
+    pub delta: Delta,
+}
+
 #[derive(Debug)]
 pub struct DateSpec {
     pub start: NaiveDate,
@@ -105,7 +113,7 @@ pub struct DateSpec {
     pub end: Option<NaiveDate>,
     pub end_delta: Option<Delta>,
     pub end_time: Option<Time>,
-    pub repeat: Option<Delta>,
+    pub repeat: Option<Repeat>,
 }
 
 #[derive(Debug)]
diff --git a/src/files/format.rs b/src/files/format.rs
index 2c8318a..e99086f 100644
--- a/src/files/format.rs
+++ b/src/files/format.rs
@@ -4,7 +4,7 @@ use chrono::Datelike;
 
 use super::commands::{
     Birthday, BirthdaySpec, Command, DateSpec, Delta, DeltaStep, Done, DoneDate, Expr, File,
-    FormulaSpec, Note, Spec, Task, Time, Var, Weekday, WeekdaySpec,
+    FormulaSpec, Note, Repeat, Spec, Task, Time, Var, Weekday, WeekdaySpec,
 };
 
 fn format_desc(f: &mut fmt::Formatter<'_>, desc: &[String]) -> fmt::Result {
@@ -52,6 +52,15 @@ impl fmt::Display for Delta {
     }
 }
 
+impl fmt::Display for Repeat {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if self.start_at_done {
+            write!(f, "done ")?;
+        }
+        write!(f, "{}", self.delta)
+    }
+}
+
 impl fmt::Display for DateSpec {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // Start
diff --git a/src/files/grammar.pest b/src/files/grammar.pest
index c9cb45e..aa027da 100644
--- a/src/files/grammar.pest
+++ b/src/files/grammar.pest
@@ -89,7 +89,8 @@ expr = { term ~ (op ~ term)* }
 
 date_fixed_start = { datum ~ delta? ~ time? }
 date_fixed_end = { datum ~ delta? ~ time? | delta ~ time? | time }
-date_fixed_repeat = { delta }
+repeat_done = { "done" }
+date_fixed_repeat = { repeat_done? ~ delta }
 date_fixed = { date_fixed_start ~ ("--" ~ date_fixed_end)? ~ (";" ~ date_fixed_repeat)? }
 
 date_expr_start = { ("*" | paren_expr) ~ delta? ~ time? }
diff --git a/src/files/parse.rs b/src/files/parse.rs
index 16c44e4..0b404be 100644
--- a/src/files/parse.rs
+++ b/src/files/parse.rs
@@ -7,6 +7,8 @@ use pest::iterators::Pair;
 use pest::prec_climber::{Assoc, Operator, PrecClimber};
 use pest::{Parser, Span};
 
+use crate::files::commands::Repeat;
+
 use super::commands::{
     Birthday, BirthdaySpec, Command, DateSpec, Delta, DeltaStep, Done, DoneDate, Expr, File,
     FormulaSpec, Note, Spec, Task, Time, Var, Weekday, WeekdaySpec,
@@ -251,13 +253,25 @@ fn parse_date_fixed_end(p: Pair<'_, Rule>, spec: &mut DateSpec) -> Result<()> {
 
 fn parse_date_fixed_repeat(p: Pair<'_, Rule>, spec: &mut DateSpec) -> Result<()> {
     assert_eq!(p.as_rule(), Rule::date_fixed_repeat);
-    let mut p = p.into_inner();
+    let mut ps = p.into_inner().collect::<Vec<_>>();
 
-    if let Some(p) = p.next() {
-        spec.repeat = Some(parse_delta(p)?);
-    }
+    let repeat = match ps.len() {
+        1 => Repeat {
+            start_at_done: false,
+            delta: parse_delta(ps.pop().unwrap())?,
+        },
+        2 => {
+            assert_eq!(ps[0].as_rule(), Rule::repeat_done);
+            Repeat {
+                start_at_done: true,
+                delta: parse_delta(ps.pop().unwrap())?,
+            }
+        }
+        _ => unreachable!(),
+    };
+
+    spec.repeat = Some(repeat);
 
-    assert_eq!(p.next(), None);
     Ok(())
 }