From 2a1560cfb9c41f244d90086da14ab2f73d20c5e2 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Wed, 17 Nov 2021 22:40:11 +0100
Subject: [PATCH] Start parsing lines

---
 src/main.rs       |  4 ++
 src/parse.rs      | 16 ++++++++
 src/parse/line.rs | 97 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 117 insertions(+)
 create mode 100644 src/parse.rs
 create mode 100644 src/parse/line.rs

diff --git a/src/main.rs b/src/main.rs
index 887b3bc..68a0165 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,7 @@ use std::path::PathBuf;
 use structopt::StructOpt;
 
 mod commands;
+mod parse;
 
 #[derive(Debug, StructOpt)]
 pub struct Opt {
@@ -13,4 +14,7 @@ pub struct Opt {
 fn main() {
     let opt = Opt::from_args();
     println!("{:#?}", opt);
+
+    let commands = parse::parse(&opt.file);
+    println!("{:#?}", commands);
 }
diff --git a/src/parse.rs b/src/parse.rs
new file mode 100644
index 0000000..9f938be
--- /dev/null
+++ b/src/parse.rs
@@ -0,0 +1,16 @@
+use std::fs;
+use std::path::Path;
+
+use crate::commands::Command;
+
+use self::line::parse_lines;
+
+mod line;
+
+pub fn parse(file: &Path) -> anyhow::Result<Vec<Command>> {
+    let content = fs::read_to_string(file)?;
+    let lines = parse_lines(&content)?;
+
+    println!("{:#?}", lines);
+    todo!()
+}
diff --git a/src/parse/line.rs b/src/parse/line.rs
new file mode 100644
index 0000000..12f3bea
--- /dev/null
+++ b/src/parse/line.rs
@@ -0,0 +1,97 @@
+use std::result;
+
+use chrono::NaiveDate;
+
+use crate::commands::{BirthdaySpec, Done, Spec};
+
+#[derive(Debug)]
+pub enum Line {
+    Empty,
+    Indented(String),
+
+    Task(String),
+    Note(String),
+    Birthday(String),
+    Date(Spec),
+    BDate(BirthdaySpec),
+    From(NaiveDate),
+    Until(NaiveDate),
+    Except(NaiveDate),
+    Done(Done),
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("line {line}: unknown command {name:?}")]
+    UnknownCommand { line: usize, name: String },
+    #[error("line {line}: unknown format")]
+    UnknownFormat { line: usize },
+}
+
+type Result<T> = result::Result<T, Error>;
+
+pub fn parse_lines(content: &str) -> Result<Vec<Line>> {
+    content
+        .lines()
+        .enumerate()
+        .map(|(line, content)| parse_line(line, content))
+        .collect()
+}
+
+fn parse_line(line: usize, content: &str) -> Result<Line> {
+    println!("Parsing line {:?}", content);
+
+    if content.is_empty() {
+        Ok(Line::Empty)
+    } else if content.starts_with('\t') || content.starts_with(' ') {
+        Ok(Line::Indented(content.to_string()))
+    } else if let Some((name, rest)) = parse_command(content) {
+        match name {
+            "TASK" => Ok(Line::Task(rest.to_string())),
+            "NOTE" => Ok(Line::Note(rest.to_string())),
+            "BIRTHDAY" => Ok(Line::Birthday(rest.to_string())),
+            "DATE" => parse_date(rest),
+            "BDATE" => parse_bdate(rest),
+            "FROM" => parse_datum(rest).map(Line::From),
+            "UNTIL" => parse_datum(rest).map(Line::Until),
+            "EXCEPT" => parse_datum(rest).map(Line::Except),
+            "DONE" => parse_done(rest),
+            _ => Err(Error::UnknownCommand {
+                line,
+                name: name.to_string(),
+            }),
+        }
+    } else {
+        Err(Error::UnknownFormat { line })
+    }
+}
+
+fn parse_command(line: &str) -> Option<(&str, &str)> {
+    if let Some(space) = line.find(' ') {
+        let name = &line[..space];
+        let content = &line[space + 1..];
+        Some((name, content))
+    } else {
+        None
+    }
+}
+
+fn parse_date(s: &str) -> Result<Line> {
+    println!("  parsing date from {:?}", s);
+    Ok(Line::Empty) // TODO
+}
+
+fn parse_bdate(s: &str) -> Result<Line> {
+    println!("  parsing bdate from {:?}", s);
+    Ok(Line::Empty) // TODO
+}
+
+fn parse_datum(s: &str) -> Result<NaiveDate> {
+    println!("  parsing datum from {:?}", s);
+    Ok(NaiveDate::from_ymd(2015, 3, 14)) // TODO
+}
+
+fn parse_done(s: &str) -> Result<Line> {
+    println!("  parsing done from {:?}", s);
+    Ok(Line::Empty) // TODO
+}