Support marking multiple tasks as done

Not yet exposed via the CLI though

src/cli/done.rs

@@ -1,24 +1,36 @@
+use std::vec;
+
 use chrono::NaiveDateTime;
 
 use crate::eval::Entry;
 use crate::files::commands::Done;
 use crate::files::Files;
 
-use super::error::Result;
+use super::error::{Error, Result};
 use super::layout::line::LineLayout;
 
 pub fn mark_done(
     files: &mut Files,
     entries: &[Entry],
     layout: &LineLayout,
-    number: usize,
+    numbers: &[usize],
     now: NaiveDateTime,
 ) -> Result<()> {
-    let entry = &entries[layout.look_up_number(number)?];
-    let done = Done {
-        date: entry.dates.map(|dates| dates.into()),
-        done_at: now.date(),
-    };
-    files.add_done(number, entry.source, done)?;
-    Ok(())
+    let mut not_tasks = vec![];
+    for &number in numbers {
+        let entry = &entries[layout.look_up_number(number)?];
+        let done = Done {
+            date: entry.dates.map(|dates| dates.into()),
+            done_at: now.date(),
+        };
+        if !files.add_done(entry.source, done) {
+            not_tasks.push(number);
+        }
+    }
+
+    if not_tasks.is_empty() {
+        Ok(())
+    } else {
+        Err(Error::NotATask(not_tasks))
+    }
 }

src/cli/error.rs

@@ -12,6 +12,8 @@ pub enum Error {
     NoNumber,
     #[error("No entry with number {0}")]
     NoSuchEntry(usize),
+    #[error("Not a task")]
+    NotATask(Vec<usize>),
 }
 
 pub type Result<T> = result::Result<T, Error>;