From f1ff3f7aaa3a4921489ccae2066312112c5471ed Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Sat, 20 Nov 2021 16:08:13 +0100
Subject: [PATCH] Evaluate birthdays

---
 src/eval.rs         | 130 ++++++++++++++++++++++++++++++++++++++++++++
 src/eval/entries.rs | 100 ++++++++++++++++++++++++++++++++++
 src/main.rs         |  13 ++++-
 3 files changed, 242 insertions(+), 1 deletion(-)
 create mode 100644 src/eval.rs
 create mode 100644 src/eval/entries.rs

diff --git a/src/eval.rs b/src/eval.rs
new file mode 100644
index 0000000..42e90f4
--- /dev/null
+++ b/src/eval.rs
@@ -0,0 +1,130 @@
+use std::collections::HashSet;
+use std::result;
+
+use chrono::{Datelike, NaiveDate};
+
+use crate::commands::{Birthday, Command, File, Note, Spec, Task};
+
+use self::entries::{DateRange, Entry, EntryKind, EntryMap};
+
+pub mod entries;
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("TODO")]
+    Todo,
+}
+
+type Result<T> = result::Result<T, Error>;
+
+fn eval_spec(spec: &Spec, index: usize, map: &mut EntryMap) -> Result<()> {
+    Ok(())
+}
+
+fn eval_task(task: &Task, index: usize, range: DateRange) -> Result<Vec<Entry>> {
+    let mut map = EntryMap::new(range);
+
+    map.from = task.from;
+    map.until = task.until;
+
+    for date in &task.except {
+        map.block(*date);
+    }
+
+    for spec in &task.when {
+        eval_spec(spec, index, &mut map)?;
+    }
+
+    let done: HashSet<NaiveDate> = task
+        .done
+        .iter()
+        .filter_map(|done| done.refering_to)
+        .collect();
+
+    for (date, entry) in map.map.iter_mut() {
+        if let Some(entry) = entry {
+            if done.contains(date) {
+                entry.kind.done();
+            }
+        }
+    }
+
+    Ok(map.drain())
+}
+
+fn eval_note(task: &Note, index: usize, range: DateRange) -> Result<Vec<Entry>> {
+    let mut map = EntryMap::new(range);
+
+    map.from = task.from;
+    map.until = task.until;
+
+    for date in &task.except {
+        map.block(*date);
+    }
+
+    for spec in &task.when {
+        eval_spec(spec, index, &mut map)?;
+    }
+
+    Ok(map.drain())
+}
+
+fn eval_birthday(bd: &Birthday, index: usize, range: DateRange) -> Result<Vec<Entry>> {
+    let mut map = EntryMap::new(range);
+
+    for year in range.years() {
+        if bd.when.year_known && year < bd.when.date.year() {
+            continue;
+        }
+
+        let title = if bd.when.year_known {
+            let age = year - bd.when.date.year();
+            format!("{} ({})", bd.title, age)
+        } else {
+            bd.title.to_string()
+        };
+
+        match bd.when.date.with_year(year) {
+            Some(date) => {
+                let mut entry = Entry::new(index, EntryKind::Birthday, title);
+                entry.start = Some(date);
+                map.insert(date, entry);
+            }
+            None => {
+                // We must've hit a non-leapyear
+                assert_eq!(bd.when.date.month(), 2);
+                assert_eq!(bd.when.date.day(), 29);
+
+                let first_date = NaiveDate::from_ymd(year, 2, 28);
+                let first_title = format!("{} (first half)", title);
+                let mut first_entry = Entry::new(index, EntryKind::Birthday, first_title);
+                first_entry.start = Some(first_date);
+                map.insert(first_date, first_entry);
+
+                let second_date = NaiveDate::from_ymd(year, 3, 1);
+                let second_title = format!("{} (second half)", title);
+                let mut second_entry = Entry::new(index, EntryKind::Birthday, second_title);
+                second_entry.start = Some(second_date);
+                map.insert(second_date, second_entry);
+            }
+        }
+    }
+
+    Ok(map.drain())
+}
+
+fn eval_command(command: &Command, index: usize, range: DateRange) -> Result<Vec<Entry>> {
+    match command {
+        Command::Task(task) => eval_task(task, index, range),
+        Command::Note(note) => eval_note(note, index, range),
+        Command::Birthday(birthday) => eval_birthday(birthday, index, range),
+    }
+}
+
+pub fn eval(file: &File, range: DateRange) -> Result<Vec<Entry>> {
+    let mut result = vec![];
+    for (index, command) in file.commands.iter().enumerate() {
+        result.append(&mut eval_command(command, index, range)?);
+    }
+    Ok(result)
+}
diff --git a/src/eval/entries.rs b/src/eval/entries.rs
new file mode 100644
index 0000000..24ebcd5
--- /dev/null
+++ b/src/eval/entries.rs
@@ -0,0 +1,100 @@
+use std::collections::HashMap;
+use std::ops::RangeInclusive;
+use std::str::from_boxed_utf8_unchecked;
+
+use chrono::{Datelike, NaiveDate};
+
+use crate::commands::Time;
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum EntryKind {
+    Task,
+    DoneTask,
+    Note,
+    Birthday,
+}
+
+impl EntryKind {
+    pub fn done(&mut self) {
+        if matches!(self, Self::Task) {
+            *self = Self::DoneTask;
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Entry {
+    pub kind: EntryKind,
+    pub title: String,
+    pub desc: Vec<String>,
+
+    /// Index in the source file
+    pub source: usize,
+
+    pub start: Option<NaiveDate>,
+    pub start_time: Option<Time>,
+    pub end: Option<NaiveDate>,
+    pub end_time: Option<Time>,
+}
+
+impl Entry {
+    pub fn new(source: usize, kind: EntryKind, title: String) -> Self {
+        Self {
+            kind,
+            title,
+            desc: vec![],
+            source,
+            start: None,
+            start_time: None,
+            end: None,
+            end_time: None,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct DateRange {
+    pub from: NaiveDate,
+    pub until: NaiveDate,
+}
+
+impl DateRange {
+    pub fn new(from: NaiveDate, until: NaiveDate) -> Self {
+        assert!(from <= until);
+        Self { from, until }
+    }
+
+    pub fn years(&self) -> RangeInclusive<i32> {
+        self.from.year()..=self.until.year()
+    }
+}
+
+pub struct EntryMap {
+    pub range: DateRange,
+    pub from: Option<NaiveDate>,
+    pub until: Option<NaiveDate>,
+    pub map: HashMap<NaiveDate, Option<Entry>>,
+}
+
+impl EntryMap {
+    pub fn new(range: DateRange) -> Self {
+        Self {
+            range,
+            from: None,
+            until: None,
+            map: HashMap::new(),
+        }
+    }
+
+    pub fn block(&mut self, date: NaiveDate) {
+        self.map.entry(date).or_insert(None);
+    }
+
+    pub fn insert(&mut self, date: NaiveDate, entry: Entry) {
+        self.map.entry(date).or_insert(Some(entry));
+    }
+
+    pub fn drain(&mut self) -> Vec<Entry> {
+        self.map.drain().filter_map(|(_, entry)| entry).collect()
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 530d952..b1f788c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,9 +1,13 @@
 use std::fs;
 use std::path::PathBuf;
 
+use chrono::NaiveDate;
 use structopt::StructOpt;
 
+use crate::eval::entries::DateRange;
+
 mod commands;
+mod eval;
 mod format;
 mod parse;
 
@@ -17,6 +21,13 @@ fn main() -> anyhow::Result<()> {
     let opt = Opt::from_args();
     let content = fs::read_to_string(&opt.file)?;
     let file = parse::parse(&opt.file, &content)?;
-    print!("{}", file);
+    let entries = eval::eval(
+        &file,
+        DateRange::new(
+            NaiveDate::from_ymd(2021, 1, 1),
+            NaiveDate::from_ymd(2021, 12, 31),
+        ),
+    )?;
+    println!("{:#?}", entries);
     Ok(())
 }