Add the exercises command

Subcommands have been added to it which are similar to the ones on words
on purpose.

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>

3 files changed, 261 insertions, 2 deletions

diff --git a/crates/cli/src/exercises.rs b/crates/cli/src/exercises.rs
new file mode 100644
index 0000000..a4bff78
--- /dev/null
+++ b/crates/cli/src/exercises.rs
@@ -0,0 +1,254 @@
+use inquire::{Confirm, Editor, Select, Text};
+use mihi::{Exercise, ExerciseKind};
+use std::vec::IntoIter;
+
+// Show the help message.
+fn help(msg: Option<&str>) {
+    if msg.is_some() {
+        println!("{}.\n", msg.unwrap());
+    }
+
+    println!("mihi exercises: Manage exercises.\n");
+    println!("usage: mihi exercises [OPTIONS] <subcommand>\n");
+
+    println!("Options:");
+    println!("   -h, --help\t\tPrint this message.");
+
+    println!("\nSubcommands:");
+    println!("   create\t\tCreate a new exercise.");
+    println!("   edit\t\t\tEdit information from an exercise.");
+    println!("   ls\t\t\tList exercises from the database.");
+    println!("   rm\t\t\tRemove an exercises from the database.");
+}
+
+// Interactively ask the user to fill up an exercise based on the given
+// `exercise` object.
+fn ask_for_exercise_based_on(exercise: Exercise) -> Result<Exercise, String> {
+    let Ok(title) = Text::new("Title:")
+        .with_initial_value(&exercise.title)
+        .prompt()
+    else {
+        return Err("abort!".to_string());
+    };
+    if title.trim().is_empty() {
+        return Err("the title is required".to_string());
+    }
+
+    let kinds = vec![
+        ExerciseKind::Pensum,
+        ExerciseKind::Translation,
+        ExerciseKind::Transformation,
+        ExerciseKind::Numerical,
+    ];
+    let Ok(kind) = Select::new("Kind:", kinds)
+        .with_starting_cursor(exercise.kind as usize)
+        .prompt()
+    else {
+        return Err("abort!".to_string());
+    };
+
+    let Ok(enunciate) = Editor::new("Enunciate:")
+        .with_predefined_text(&exercise.enunciate)
+        .with_file_extension(".md")
+        .prompt()
+    else {
+        return Err("abort!".to_string());
+    };
+    let enunciate = enunciate.trim().to_string();
+    if enunciate.is_empty() {
+        return Err("the enunciate is required".to_string());
+    }
+
+    let Ok(solution) = Editor::new("Solution:")
+        .with_predefined_text(&exercise.solution)
+        .with_file_extension(".md")
+        .prompt()
+    else {
+        return Err("abort!".to_string());
+    };
+    let solution = solution.trim().to_string();
+    if solution.trim().is_empty() {
+        return Err("the solution is required".to_string());
+    }
+
+    let Ok(lessons) = Editor::new("Lessons:")
+        .with_predefined_text(&exercise.lessons)
+        .with_file_extension(".md")
+        .prompt()
+    else {
+        return Err("abort!".to_string());
+    };
+    let lessons = lessons.trim().to_string();
+
+    Ok(Exercise {
+        id: exercise.id,
+        title,
+        enunciate,
+        solution,
+        lessons,
+        kind,
+    })
+}
+
+fn create(args: IntoIter<String>) -> i32 {
+    if args.len() > 0 {
+        help(Some(
+            "error: exercises: no arguments were expected for this command",
+        ));
+        return 1;
+    }
+
+    let exercise = match ask_for_exercise_based_on(Exercise::default()) {
+        Ok(ex) => ex,
+        Err(e) => {
+            println!("error: exercises: {e}");
+            return 1;
+        }
+    };
+
+    let title = exercise.title.clone();
+    match mihi::create_exercise(exercise) {
+        Ok(_) => {
+            println!("Exercise '{title}' has been successfully created!");
+            0
+        }
+        Err(e) => {
+            println!("error: exercises: {e}");
+            1
+        }
+    }
+}
+
+fn select_single_exercise(search: Option<String>) -> Result<Exercise, String> {
+    let exercises = mihi::select_by_title(search)?;
+
+    let title = match exercises.len() {
+        0 => return Err("not found".to_string()),
+        1 => exercises.first().unwrap().to_owned(),
+        _ => match Select::new("Which exercise?", exercises)
+            .with_page_size(20)
+            .prompt()
+        {
+            Ok(choice) => choice,
+            Err(_) => return Err("abort!".to_string()),
+        },
+    };
+
+    mihi::find_exercise_by_title(title.as_str())
+}
+
+fn edit(mut args: IntoIter<String>) -> i32 {
+    if args.len() > 1 {
+        help(Some("error: exercises: too many filters"));
+        return 1;
+    }
+
+    let exercise = match select_single_exercise(args.next()) {
+        Ok(exercise) => exercise,
+        Err(e) => {
+            println!("error: exercises: {e}");
+            return 1;
+        }
+    };
+
+    let exercise = match ask_for_exercise_based_on(exercise) {
+        Ok(ex) => ex,
+        Err(e) => {
+            println!("error: exercises: {e}");
+            return 1;
+        }
+    };
+
+    let title = exercise.title.clone();
+    match mihi::update_exercise(exercise) {
+        Ok(_) => {
+            println!("Exercise '{title}' has been successfully updated!");
+            0
+        }
+        Err(e) => {
+            println!("error: exercises: {e}");
+            1
+        }
+    }
+}
+
+fn rm(mut args: IntoIter<String>) -> i32 {
+    if args.len() > 1 {
+        help(Some("error: exercises: too many filters"));
+        return 1;
+    }
+
+    let exercise = match select_single_exercise(args.next()) {
+        Ok(exercise) => exercise,
+        Err(e) => {
+            println!("error: words: {e}");
+            return 1;
+        }
+    };
+    let selection = exercise.title.as_str();
+
+    let ans = Confirm::new(
+        format!("Do you really want to remove '{selection}' from the database?",).as_str(),
+    )
+    .with_default(false)
+    .prompt();
+
+    match ans {
+        Ok(true) => match mihi::delete_exercise(selection) {
+            Ok(_) => println!("Removed '{}' from the database!", selection),
+            Err(e) => {
+                println!("error: words: {e}");
+                return 1;
+            }
+        },
+        Ok(false) => {
+            println!("Doing nothing...");
+        }
+        Err(_) => return 1,
+    }
+
+    0
+}
+
+pub fn run(args: Vec<String>) {
+    if args.is_empty() {
+        help(Some(
+            "error: exercises: you have to provide at least a subcommand",
+        ));
+        std::process::exit(1);
+    }
+
+    let mut it = args.into_iter();
+
+    match it.next() {
+        Some(first) => match first.as_str() {
+            "-h" | "--help" => {
+                help(None);
+                std::process::exit(0);
+            }
+            "create" => {
+                std::process::exit(create(it));
+            }
+            "edit" => {
+                std::process::exit(edit(it));
+            }
+            "rm" => {
+                std::process::exit(rm(it));
+            }
+            _ => {
+                help(Some(
+                    format!("error: exercises: unknown flag or command '{first}'").as_str(),
+                ));
+                std::process::exit(1);
+            }
+        },
+        None => {
+            help(Some(
+                "error: exercises: you need to provide a command"
+                    .to_string()
+                    .as_str(),
+            ));
+            std::process::exit(1);
+        }
+    }
+}
diff --git a/crates/cli/src/main.rs b/crates/cli/src/main.rs
index db1de33..ffbcdae 100644
--- a/crates/cli/src/main.rs
+++ b/crates/cli/src/main.rs
@@ -1,3 +1,4 @@
+mod exercises;
 mod init;
 mod nuke;
 mod run;
@@ -48,6 +49,10 @@ fn main() {
                 let rest: Vec<String> = args.collect();
                 init::run(rest);
             }
+            "exercises" => {
+                let rest: Vec<String> = args.collect();
+                exercises::run(rest);
+            }
             "nuke" => {
                 let rest: Vec<String> = args.collect();
                 nuke::run(rest);
diff --git a/crates/cli/src/words.rs b/crates/cli/src/words.rs
index 72748ae..7db84a2 100644
--- a/crates/cli/src/words.rs
+++ b/crates/cli/src/words.rs
@@ -166,7 +166,7 @@ fn trim_flags(given: String) -> String {
     for line in given.lines() {
         let trimmed = line.trim();
 
-        if !line.trim().starts_with('#') {
+        if !trimmed.starts_with('#') {
             res.push_str(trimmed);
         }
     }
@@ -510,7 +510,7 @@ fn edit(mut args: IntoIter<String>) -> i32 {
 }
 
 fn show(mut _args: IntoIter<String>) -> i32 {
-    0
+    todo!()
 }
 
 fn rm(mut args: IntoIter<String>) -> i32 {