1 files changed, 91 insertions, 0 deletions
diff --git a/src/lecture.rs b/src/lecture.rs
new file mode 100644
index 0000000..462fd86
--- /dev/null
+++ b/src/lecture.rs
@@ -0,0 +1,91 @@
+use std::{
+    fs,
+    io,
+    path::PathBuf,
+};
+use tinytemplate::TinyTemplate;
+use regex::Regex;
+
+use crate::{Course, CourseContext, Config};
+
+fn init_lecture(course: &Course, config: &Config) {
+    let template_stream = fs::read(&config.template)
+        .expect("Couldn't open template.");
+    let template_string = String::from_utf8_lossy(&template_stream);
+
+    let mut template = TinyTemplate::new();
+    template.add_template("main", &template_string)
+        .expect("Failed initializing template.");
+
+    let context = CourseContext::from(&course, &config);
+
+    let rendered = template.render("main", &context)
+        .expect("Failed applying template");
+
+    let lecture_directory = config.root.join(&course.semester).join(&course.name)
+        .join("lecture");
+    fs::write(lecture_directory.join("main.tex"), rendered)
+        .expect("Failed making main.tex for course.");
+}
+
+fn detect_lessons(path: &PathBuf) -> io::Result<Vec<u32>> {
+    let mut lesson_numbers: Vec<u32> = Vec::new();
+    let dir_iter = fs::read_dir(path)?;
+    let pattern = Regex::new(r"les(\d+)\.tex").unwrap();
+
+    for entry in dir_iter {
+        let entry_path = entry?.path();
+        let name = entry_path.file_name().unwrap().to_string_lossy();
+        if let Some(caps) = pattern.captures(&name) {
+            let lesson_number = caps[1].parse::<u32>().unwrap();
+            lesson_numbers.push(lesson_number);
+        }
+    }
+
+    lesson_numbers.sort();
+
+    return Ok(lesson_numbers);
+}
+
+fn update_main(main_path: &PathBuf, new_lessons: String) -> io::Result<()> {
+    let main = fs::read(main_path)?;
+    let pattern = Regex::new(r"% start lessons\n( {4}\\input\{les(\d+)\.tex\}\n)* {4}% end lessons")
+        .unwrap();
+    let fmt_lessons = format!("% start lessons\n{}    %end lessons", new_lessons);
+    let main_string = String::from_utf8_lossy(&main);
+    let new_main = pattern.replace(&main_string, fmt_lessons);
+    fs::write(main_path, new_main.as_bytes())?;
+
+    Ok(())
+}
+
+pub fn new_lesson(course: &Course, config: &Config) -> String {
+    let lecture_directory = config.root.join(&course.semester).join(&course.name)
+        .join("lecture");
+
+    if !lecture_directory.try_exists().unwrap() {
+        fs::create_dir_all(&lecture_directory).unwrap();
+        init_lecture(course, config);
+    }
+
+    let mut lessons = detect_lessons(&lecture_directory)
+        .expect("Could not make sense of the lesson situation.");
+    let new_lesson = lessons.last().unwrap_or(&0).clone() + 1;
+
+    let lesson_file = format!("les{new_lesson}.tex");
+    let lesson_path = lecture_directory.join(lesson_file.clone());
+    fs::write(&lesson_path, format!("\\lesson{{{new_lesson}}}{{}}\n\n").as_bytes())
+        .expect("Unable to write to lesson file.");
+
+    lessons.push(new_lesson);
+
+    let mut lessons_string = String::new();
+
+    for num in lessons {
+        lessons_string.push_str(format!("    \\input{{les{num}.tex}}\n").as_str());
+    }
+
+    update_main(&lecture_directory.join("main.tex"), lessons_string)
+        .expect("Unable to update main.tex");
+    return lesson_file;
+}