From e678a2bb314e06093c795d69f7a139573fa976fe Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Sat, 20 Nov 2021 00:12:40 +0100
Subject: [PATCH] Implement Display for all commands

---
 src/commands.rs | 120 +++++++++++++++++---
 src/format.rs   | 286 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/main.rs     |   3 +-
 src/parse.rs    |  10 +-
 4 files changed, 396 insertions(+), 23 deletions(-)
 create mode 100644 src/format.rs

diff --git a/src/commands.rs b/src/commands.rs
index 1182875..6dc55e3 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -2,8 +2,8 @@ use chrono::NaiveDate;
 
 #[derive(Debug)]
 pub struct Time {
-    hour: u8,
-    min: u8,
+    pub hour: u8,
+    pub min: u8,
 }
 
 impl Time {
@@ -19,7 +19,7 @@ impl Time {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone, Copy)]
 pub enum Weekday {
     Monday,
     Tuesday,
@@ -30,6 +30,20 @@ pub enum Weekday {
     Sunday,
 }
 
+impl Weekday {
+    pub fn name(&self) -> &'static str {
+        match self {
+            Weekday::Monday => "mon",
+            Weekday::Tuesday => "tue",
+            Weekday::Wednesday => "wed",
+            Weekday::Thursday => "thu",
+            Weekday::Friday => "fri",
+            Weekday::Saturday => "sat",
+            Weekday::Sunday => "sun",
+        }
+    }
+}
+
 #[derive(Debug)]
 pub enum DeltaStep {
     /// `y`, move by a year, keeping the same month and day
@@ -52,6 +66,34 @@ pub enum DeltaStep {
     Weekday(i32, Weekday),
 }
 
+impl DeltaStep {
+    pub fn amount(&self) -> i32 {
+        match self {
+            DeltaStep::Year(i) => *i,
+            DeltaStep::Month(i) => *i,
+            DeltaStep::MonthReverse(i) => *i,
+            DeltaStep::Day(i) => *i,
+            DeltaStep::Week(i) => *i,
+            DeltaStep::Hour(i) => *i,
+            DeltaStep::Minute(i) => *i,
+            DeltaStep::Weekday(i, _) => *i,
+        }
+    }
+
+    pub fn name(&self) -> &'static str {
+        match self {
+            DeltaStep::Year(_) => "y",
+            DeltaStep::Month(_) => "m",
+            DeltaStep::MonthReverse(_) => "M",
+            DeltaStep::Day(_) => "d",
+            DeltaStep::Week(_) => "w",
+            DeltaStep::Hour(_) => "h",
+            DeltaStep::Minute(_) => "min",
+            DeltaStep::Weekday(_, wd) => wd.name(),
+        }
+    }
+}
+
 #[derive(Debug)]
 pub struct Delta(pub Vec<DeltaStep>);
 
@@ -77,6 +119,24 @@ pub struct WeekdaySpec {
 
 #[derive(Debug)]
 pub enum Var {
+    /// `true`, always 1
+    True,
+    /// `false`, always 0
+    False,
+    /// `mon`, always 1
+    Monday,
+    /// `tue`, always 2
+    Tuesday,
+    /// `wed`, always 3
+    Wednesday,
+    /// `thu`, always 4
+    Thursday,
+    /// `fri`, always 5
+    Friday,
+    /// `sat`, always 6
+    Saturday,
+    /// `sun`, always 7
+    Sunday,
     /// `j`, see <https://en.wikipedia.org/wiki/Julian_day>
     JulianDay,
     /// `y`
@@ -127,20 +187,6 @@ pub enum Var {
     Weekday,
     /// `e`, day of the year that easter falls on
     Easter,
-    /// `mon`, always 1
-    Monday,
-    /// `tue`, always 2
-    Tuesday,
-    /// `wed`, always 3
-    Wednesday,
-    /// `thu`, always 4
-    Thursday,
-    /// `fri`, always 5
-    Friday,
-    /// `sat`, always 6
-    Saturday,
-    /// `sun`, always 7
-    Sunday,
     /// `isWeekday`, whether the current day is one of mon-fri
     IsWeekday,
     /// `isWeekend`, whether the current day is one of sat-sun
@@ -149,6 +195,46 @@ pub enum Var {
     IsLeapYear,
 }
 
+impl Var {
+    pub fn name(&self) -> &'static str {
+        match self {
+            // Constants
+            Var::True => "true",
+            Var::False => "false",
+            Var::Monday => "mon",
+            Var::Tuesday => "tue",
+            Var::Wednesday => "wed",
+            Var::Thursday => "thu",
+            Var::Friday => "fri",
+            Var::Saturday => "sat",
+            Var::Sunday => "sun",
+            // Variables
+            Var::JulianDay => "j",
+            Var::Year => "y",
+            Var::YearLength => "yl",
+            Var::YearDay => "yd",
+            Var::YearDayReverse => "yD",
+            Var::YearWeek => "yw",
+            Var::YearWeekReverse => "yW",
+            Var::Month => "m",
+            Var::MonthLength => "ml",
+            Var::MonthWeek => "mw",
+            Var::MonthWeekReverse => "mW",
+            Var::Day => "d",
+            Var::DayReverse => "D",
+            Var::IsoYear => "iy",
+            Var::IsoYearLength => "iyl",
+            Var::IsoWeek => "iw",
+            Var::Weekday => "wd",
+            Var::Easter => "e",
+            // Variables with "boolean" values
+            Var::IsWeekday => "isWeekday",
+            Var::IsWeekend => "isWeekend",
+            Var::IsLeapYear => "isLeapYear",
+        }
+    }
+}
+
 #[derive(Debug)]
 pub enum Expr {
     Lit(i64),
diff --git a/src/format.rs b/src/format.rs
new file mode 100644
index 0000000..ab847ba
--- /dev/null
+++ b/src/format.rs
@@ -0,0 +1,286 @@
+use std::fmt;
+
+use chrono::Datelike;
+
+use crate::commands::{
+    Birthday, BirthdaySpec, Command, DateSpec, Delta, DeltaStep, Done, Expr, File, FormulaSpec,
+    Note, Spec, Task, Time, Var, Weekday, WeekdaySpec,
+};
+
+fn format_desc(f: &mut fmt::Formatter<'_>, desc: &[String]) -> fmt::Result {
+    for line in desc {
+        if line.is_empty() {
+            writeln!(f, "#")?;
+        } else {
+            writeln!(f, "# {}", line)?;
+        }
+    }
+    Ok(())
+}
+
+impl fmt::Display for Time {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{:02}:{:02}", self.hour, self.min)
+    }
+}
+
+impl fmt::Display for Weekday {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.name())
+    }
+}
+
+fn format_delta_step(f: &mut fmt::Formatter<'_>, step: &DeltaStep, sign: &mut i32) -> fmt::Result {
+    let amount = step.amount();
+    if *sign == 0 || (amount != 0 && *sign != amount.signum()) {
+        write!(f, "{}", if amount >= 0 { "+" } else { "-" })?;
+    }
+    *sign = if amount >= 0 { 1 } else { -1 };
+    if amount.abs() != 1 {
+        write!(f, "{}", amount.abs())?;
+    }
+    write!(f, "{}", step.name())
+}
+
+impl fmt::Display for Delta {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut sign = 0;
+        for step in &self.0 {
+            format_delta_step(f, step, &mut sign)?;
+        }
+        Ok(())
+    }
+}
+
+impl fmt::Display for DateSpec {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // Start
+        write!(f, "{}", self.start)?;
+        for delta in &self.start_delta {
+            write!(f, " {}", delta)?;
+        }
+        for time in &self.start_time {
+            write!(f, " {}", time)?;
+        }
+
+        // End
+        if self.end.is_some() || self.end_delta.is_some() || self.end_time.is_some() {
+            write!(f, " --")?;
+            if let Some(date) = self.end {
+                write!(f, " {}", date)?;
+            }
+            if let Some(delta) = &self.end_delta {
+                write!(f, " {}", delta)?;
+            }
+            if let Some(time) = &self.end_time {
+                write!(f, " {}", time)?;
+            }
+        }
+
+        // Repeat
+        if let Some(repeat) = &self.repeat {
+            write!(f, "; {}", repeat)?;
+        }
+
+        Ok(())
+    }
+}
+
+impl fmt::Display for WeekdaySpec {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // Start
+        write!(f, "{}", self.start)?;
+        for time in &self.start_time {
+            write!(f, " {}", time)?;
+        }
+
+        // End
+        if self.end.is_some() || self.end_delta.is_some() || self.end_time.is_some() {
+            write!(f, " --")?;
+            if let Some(wd) = self.end {
+                write!(f, " {}", wd)?;
+            }
+            if let Some(delta) = &self.end_delta {
+                write!(f, " {}", delta)?;
+            }
+            if let Some(time) = &self.end_time {
+                write!(f, " {}", time)?;
+            }
+        }
+
+        Ok(())
+    }
+}
+
+impl fmt::Display for Var {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.name())
+    }
+}
+
+impl fmt::Display for Expr {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Expr::Lit(i) => write!(f, "{}", i),
+            Expr::Var(v) => write!(f, "{}", v),
+            Expr::Paren(e) => write!(f, "({})", e),
+            Expr::Neg(e) => write!(f, "-{}", e),
+            Expr::Add(a, b) => write!(f, "{} + {}", a, b),
+            Expr::Sub(a, b) => write!(f, "{} - {}", a, b),
+            Expr::Mul(a, b) => write!(f, "{} * {}", a, b),
+            Expr::Div(a, b) => write!(f, "{} / {}", a, b),
+            Expr::Mod(a, b) => write!(f, "{} % {}", a, b),
+            Expr::Eq(a, b) => write!(f, "{} = {}", a, b),
+            Expr::Neq(a, b) => write!(f, "{} != {}", a, b),
+            Expr::Lt(a, b) => write!(f, "{} < {}", a, b),
+            Expr::Lte(a, b) => write!(f, "{} <= {}", a, b),
+            Expr::Gt(a, b) => write!(f, "{} > {}", a, b),
+            Expr::Gte(a, b) => write!(f, "{} >= {}", a, b),
+            Expr::Not(e) => write!(f, "!{}", e),
+            Expr::And(a, b) => write!(f, "{} & {}", a, b),
+            Expr::Or(a, b) => write!(f, "{} | {}", a, b),
+            Expr::Xor(a, b) => write!(f, "{} ^ {}", a, b),
+        }
+    }
+}
+
+impl fmt::Display for FormulaSpec {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // Start
+        if let Some(expr) = &self.start {
+            write!(f, "({})", expr)?;
+        } else {
+            write!(f, "*")?;
+        }
+        for delta in &self.start_delta {
+            write!(f, " {}", delta)?;
+        }
+        for time in &self.start_time {
+            write!(f, " {}", time)?;
+        }
+
+        // End
+        if self.end_delta.is_some() || self.end_time.is_some() {
+            write!(f, " --")?;
+            if let Some(delta) = &self.end_delta {
+                write!(f, " {}", delta)?;
+            }
+            if let Some(time) = &self.end_time {
+                write!(f, " {}", time)?;
+            }
+        }
+
+        Ok(())
+    }
+}
+
+impl fmt::Display for Spec {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "DATE ")?;
+        match self {
+            Spec::Date(spec) => write!(f, "{}", spec)?,
+            Spec::Weekday(spec) => write!(f, "{}", spec)?,
+            Spec::Formula(spec) => write!(f, "{}", spec)?,
+        }
+        writeln!(f)
+    }
+}
+
+impl fmt::Display for Done {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "DONE")?;
+        if let Some(date) = &self.refering_to {
+            write!(f, " {}", date)?;
+        }
+        if let Some((date, time)) = &self.created_at {
+            write!(f, " ({} {})", date, time)?;
+        }
+        writeln!(f)
+    }
+}
+
+impl fmt::Display for Task {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        writeln!(f, "TASK {}", self.title)?;
+        for spec in &self.when {
+            write!(f, "{}", spec)?;
+        }
+        if let Some(date) = self.from {
+            writeln!(f, "FROM {}", date)?;
+        }
+        if let Some(date) = self.until {
+            writeln!(f, "UNTIL {}", date)?;
+        }
+        for date in &self.except {
+            writeln!(f, "EXCEPT {}", date)?;
+        }
+        for done in &self.done {
+            write!(f, "{}", done)?;
+        }
+        format_desc(f, &self.desc)?;
+        Ok(())
+    }
+}
+
+impl fmt::Display for Note {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        writeln!(f, "NOTE {}", self.title)?;
+        for spec in &self.when {
+            write!(f, "{}", spec)?;
+        }
+        if let Some(date) = self.from {
+            writeln!(f, "FROM {}", date)?;
+        }
+        if let Some(date) = self.until {
+            writeln!(f, "UNTIL {}", date)?;
+        }
+        for date in &self.except {
+            writeln!(f, "EXCEPT {}", date)?;
+        }
+        format_desc(f, &self.desc)?;
+        Ok(())
+    }
+}
+
+impl fmt::Display for BirthdaySpec {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if self.year_known {
+            writeln!(f, "BDATE {}", self.date)
+        } else {
+            writeln!(f, "BDATE ?-{:02}-{:02}", self.date.month(), self.date.day())
+        }
+    }
+}
+
+impl fmt::Display for Birthday {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        writeln!(f, "BIRTHDAY {}", self.title)?;
+        write!(f, "{}", self.when)?;
+        format_desc(f, &self.desc)?;
+        Ok(())
+    }
+}
+
+impl fmt::Display for Command {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Command::Task(task) => write!(f, "{}", task),
+            Command::Note(note) => write!(f, "{}", note),
+            Command::Birthday(birthday) => write!(f, "{}", birthday),
+        }
+    }
+}
+
+impl fmt::Display for File {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut commands = self.commands.iter();
+        if let Some(command) = commands.next() {
+            write!(f, "{}", command)?;
+            for command in commands {
+                writeln!(f)?;
+                write!(f, "{}", command)?;
+            }
+        }
+        Ok(())
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index ffc434b..530d952 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,6 +4,7 @@ use std::path::PathBuf;
 use structopt::StructOpt;
 
 mod commands;
+mod format;
 mod parse;
 
 #[derive(Debug, StructOpt)]
@@ -16,6 +17,6 @@ fn main() -> anyhow::Result<()> {
     let opt = Opt::from_args();
     let content = fs::read_to_string(&opt.file)?;
     let file = parse::parse(&opt.file, &content)?;
-    println!("{:#?}", file);
+    print!("{}", file);
     Ok(())
 }
diff --git a/src/parse.rs b/src/parse.rs
index fd68477..036fb28 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -275,11 +275,11 @@ fn parse_date_fixed(p: Pair<Rule>) -> Result<DateSpec> {
     Ok(spec)
 }
 
-fn parse_boolean(p: Pair<Rule>) -> bool {
+fn parse_boolean(p: Pair<Rule>) -> Var {
     assert_eq!(p.as_rule(), Rule::boolean);
     match p.as_str() {
-        "true" => true,
-        "false" => false,
+        "true" => Var::True,
+        "false" => Var::False,
         _ => unreachable!(),
     }
 }
@@ -345,7 +345,7 @@ fn parse_term(p: Pair<Rule>) -> Expr {
     let p = p.into_inner().next().unwrap();
     match p.as_rule() {
         Rule::number => Expr::Lit(parse_number(p).into()),
-        Rule::boolean => Expr::Lit(if parse_boolean(p) { 1 } else { 0 }),
+        Rule::boolean => Expr::Var(parse_boolean(p)),
         Rule::variable => Expr::Var(parse_variable(p)),
         Rule::unop_expr => parse_unop_expr(p),
         Rule::paren_expr => parse_paren_expr(p),
@@ -404,7 +404,7 @@ fn parse_date_expr_start(p: Pair<Rule>, spec: &mut FormulaSpec) -> Result<()> {
 
     for p in p.into_inner() {
         match p.as_rule() {
-            Rule::paren_expr => spec.start = Some(parse_paren_expr(p)),
+            Rule::paren_expr => spec.start = Some(parse_expr(p.into_inner().next().unwrap())),
             Rule::delta => spec.start_delta = Some(parse_delta(p)?),
             Rule::time => spec.start_time = Some(parse_time(p)?),
             _ => unreachable!(),