Improve error handling

src/cli.rs

@@ -1,14 +1,15 @@
 use std::path::PathBuf;
 use std::{process, result};
 
-use chrono::{Duration, NaiveDate};
+use chrono::{Duration, NaiveDate, NaiveDateTime};
 use directories::ProjectDirs;
 use structopt::StructOpt;
 
-use crate::eval::{DateRange, EntryMode};
+use crate::eval::{DateRange, Entry, EntryMode};
 use crate::files::{self, Files};
 
 use self::error::Result;
+use self::layout::line::LineLayout;
 
 mod done;
 mod error;
@@ -67,7 +68,63 @@ fn load_files(opt: &Opt) -> result::Result<Files, files::Error> {
     Files::load(&file)
 }
 
-pub fn run() -> Result<()> {
+fn find_now(opt: &Opt, files: &Files) -> NaiveDateTime {
+    let now = files.now().naive_local();
+    if let Some(date) = opt.date {
+        date.and_time(now.time())
+    } else {
+        now
+    }
+}
+
+fn find_range(opt: &Opt, now: NaiveDateTime) -> DateRange {
+    let range_date = opt.date.unwrap_or_else(|| now.date());
+    DateRange::new(
+        range_date - Duration::days(opt.before.into()),
+        range_date + Duration::days(opt.after.into()),
+    )
+    .expect("determine range")
+}
+
+fn find_entries(files: &Files, range: DateRange) -> Result<Vec<Entry>> {
+    Ok(files.eval(EntryMode::Relevant, range)?)
+}
+
+fn find_layout(
+    files: &Files,
+    entries: &[Entry],
+    range: DateRange,
+    now: NaiveDateTime,
+) -> LineLayout {
+    layout::layout(files, entries, range, now)
+}
+
+fn run_command(opt: &Opt, files: &mut Files, range: DateRange, now: NaiveDateTime) -> Result<()> {
+    match &opt.command {
+        None => {
+            let entries = find_entries(files, range)?;
+            let layout = find_layout(files, &entries, range, now);
+            print::print(&layout);
+        }
+        Some(Command::Show { entries: ns }) => {
+            let entries = find_entries(files, range)?;
+            let layout = find_layout(files, &entries, range, now);
+            show::show(files, &entries, &layout, ns)?;
+        }
+        Some(Command::Done { entries: ns }) => {
+            let entries = find_entries(files, range)?;
+            let layout = find_layout(files, &entries, range, now);
+            done::done(files, &entries, &layout, ns, now)?;
+            let entries = find_entries(files, range)?;
+            let layout = find_layout(files, &entries, range, now);
+            print::print(&layout);
+        }
+        Some(Command::Fmt) => files.mark_all_dirty(),
+    }
+    Ok(())
+}
+
+pub fn run() {
     let opt = Opt::from_args();
 
     let mut files = match load_files(&opt) {
@@ -78,33 +135,16 @@ pub fn run() -> Result<()> {
         }
     };
 
-    let now = files.now().naive_local();
+    let now = find_now(&opt, &files);
+    let range = find_range(&opt, now);
 
-    let range_date = opt.date.unwrap_or_else(|| now.date());
-    let range = DateRange::new(
-        range_date - Duration::days(opt.before.into()),
-        range_date + Duration::days(opt.after.into()),
-    )
-    .expect("determine range");
-
-    let entries = files.eval(EntryMode::Relevant, range)?;
-    let layout = layout::layout(&files, &entries, range, now);
-
-    match opt.command {
-        None => print::print(&layout),
-        Some(Command::Show { entries: numbers }) => {
-            show::show(&files, &entries, &layout, &numbers)?
-        }
-        Some(Command::Done { entries: numbers }) => {
-            done::done(&mut files, &entries, &layout, &numbers, now)?
-        }
-        Some(Command::Fmt) => files.mark_all_dirty(),
+    if let Err(e) = run_command(&opt, &mut files, range, now) {
+        e.print(&files);
+        process::exit(1);
     }
 
     if let Err(e) = files.save() {
         e.print();
         process::exit(1);
     }
-
-    Ok(())
 }

src/cli/error.rs

@@ -1,19 +1,35 @@
 use std::result;
 
-use crate::{eval, files};
+use crate::eval;
+use crate::files::Files;
 
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
-    #[error("{0}")]
-    Files(#[from] files::Error),
     #[error("{0}")]
     Eval(#[from] eval::Error),
-    #[error("No number specified")]
-    NoNumber,
     #[error("No entry with number {0}")]
     NoSuchEntry(usize),
     #[error("Not a task")]
     NotATask(Vec<usize>),
 }
 
+impl Error {
+    pub fn print(&self, files: &Files) {
+        match self {
+            Error::Eval(e) => e.print(files),
+            Error::NoSuchEntry(n) => eprintln!("No entry with number {}", n),
+            Error::NotATask(ns) => {
+                if ns.is_empty() {
+                    eprintln!("Not a task.");
+                } else if ns.len() == 1 {
+                    eprintln!("{} is not a task.", ns[0]);
+                } else {
+                    let ns = ns.iter().map(|n| n.to_string()).collect::<Vec<_>>();
+                    eprintln!("{} are not tasks.", ns.join(", "));
+                }
+            }
+        }
+    }
+}
+
 pub type Result<T> = result::Result<T, Error>;

src/eval/error.rs

@@ -3,6 +3,7 @@ use std::result;
 use chrono::NaiveDate;
 
 use crate::files::primitives::{Span, Time};
+use crate::files::Files;
 
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
@@ -62,4 +63,105 @@ pub enum Error {
     },
 }
 
+impl Error {
+    fn print_at(files: &Files, file: &usize, span: &Span, message: String) {
+        use pest::error as pe;
+        let (name, content) = files.file(*file).expect("file index is valid");
+        let span = pest::Span::new(content, span.start, span.end).expect("span is valid");
+        let variant = pe::ErrorVariant::<()>::CustomError { message };
+        let error = pe::Error::new_from_span(variant, span).with_path(&name.to_string_lossy());
+        eprintln!("{}", error);
+    }
+
+    fn fmt_date_time(date: NaiveDate, time: Option<Time>) -> String {
+        match time {
+            None => format!("{}", date),
+            Some(time) => format!("{} {}", date, time),
+        }
+    }
+
+    pub fn print(&self, files: &Files) {
+        match self {
+            Error::DeltaInvalidStep {
+                file,
+                span,
+                start,
+                start_time,
+                prev,
+                prev_time,
+            } => {
+                let msg = format!(
+                    "Delta step resulted in invalid date\
+                    \nInitial start: {}\
+                    \nPrevious step: {}",
+                    Self::fmt_date_time(*start, *start_time),
+                    Self::fmt_date_time(*prev, *prev_time),
+                );
+                Self::print_at(files, file, span, msg);
+            }
+            Error::DeltaNoTime {
+                file,
+                span,
+                start,
+                prev,
+            } => {
+                let msg = format!(
+                    "Time-based delta step applied to date without time\
+                    \nInitial start: {}\
+                    \nPrevious step: {}",
+                    start, prev
+                );
+                Self::print_at(files, file, span, msg);
+            }
+            Error::RepeatDidNotMoveForwards {
+                file,
+                span,
+                from,
+                to,
+            } => {
+                let msg = format!(
+                    "Repeat delta did not move forwards\
+                    \nMoved from {} to {}",
+                    from, to
+                );
+                Self::print_at(files, file, span, msg);
+            }
+            Error::MoveWithoutSource { file, span } => {
+                let msg = "Tried to move nonexisting entry".to_string();
+                Self::print_at(files, file, span, msg);
+            }
+            Error::DivByZero { file, span, date } => {
+                let msg = format!(
+                    "Tried to divide by zero\
+                    \nAt date: {}",
+                    date
+                );
+                Self::print_at(files, file, span, msg);
+            }
+            Error::ModByZero { file, span, date } => {
+                let msg = format!(
+                    "Tried to modulo by zero\
+                    \nAt date: {}",
+                    date
+                );
+                Self::print_at(files, file, span, msg);
+            }
+            Error::Easter {
+                file,
+                span,
+                date,
+                msg,
+            } => {
+                let msg = format!(
+                    "Failed to calculate easter\
+                    \nAt date: {}\
+                    \nReason: {}",
+                    date, msg
+                );
+                Self::print_at(files, file, span, msg);
+            }
+        }
+    }
+}
+
 pub type Result<T> = result::Result<T, Error>;

src/files.rs

@@ -163,6 +163,12 @@ impl Files {
         &self.files[source.file].file.commands[source.command]
     }
 
+    pub fn file(&self, file: usize) -> Option<(&Path, &str)> {
+        self.files
+            .get(file)
+            .map(|f| (&f.name as &Path, &f.file.contents as &str))
+    }
+
     /// Add a [`Done`] statement to the task identified by `source`.
     ///
     /// Returns whether the addition was successful. It can fail if the entry

src/files/error.rs

@@ -27,7 +27,7 @@ pub enum Error {
 }
 
 impl Error {
-    pub fn print(self) {
+    pub fn print(&self) {
         match self {
             Error::ResolvePath { path, error } => {
                 eprintln!("Could not resolve path {:?}:", path);

src/main.rs

@@ -7,7 +7,6 @@ mod cli;
 mod eval;
 mod files;
 
-fn main() -> anyhow::Result<()> {
-    cli::run()?;
-    Ok(())
+fn main() {
+    cli::run();
 }