add output format configuration

Add functionality to output application information in pretty formatting
(human-readable) or plain json for integrating application output with
other tools.

Cargo.toml

@@ -47,6 +47,7 @@ clap_autocomplete = "0.4.2"
 tantivy = "0.22.0"
 clap_complete = "4.5.40"
 clap_complete_command = "0.6.1"
+atty = "0.2.14"
 [dependencies.sea-orm-migration]
 version = "1.1.0"
 features = [
@@ -59,6 +60,7 @@ async-stream = { version = "0.3" }
 futures-util = { version = "0.3" }
 clap = { version = "4" }
 directories = { version = "5.0.0" }
+atty = "0.2"
 
 [profile.dist]
 inherits = "release"

src/command/get_substance.rs

@@ -69,15 +69,14 @@ mod tests
     use crate::lib::migrate_database;
     use crate::lib::Context;
     use crate::lib::DATABASE_CONNECTION;
+    use crate::OutputFormat;
 
     #[async_std::test]
     async fn should_return_caffeine()
     {
         migrate_database(&DATABASE_CONNECTION).await.unwrap();
 
-        let context = Context {
-            database_connection: &DATABASE_CONNECTION,
-        };
+        let context = Context {database_connection: &DATABASE_CONNECTION, output_format: OutputFormat::Pretty };
 
 
         let command = GetSubstance {

src/ingestion.rs

@@ -4,6 +4,7 @@ use crate::lib::parse_date_string;
 use crate::lib::route_of_administration::RouteOfAdministrationClassification;
 use crate::lib::CommandHandler;
 use crate::lib::Context;
+use crate::lib::output::{Formattable, FormattableVec};
 use crate::orm::ingestion;
 use crate::orm::prelude::Ingestion;
 use async_std::task::block_on;
@@ -40,6 +41,8 @@ pub struct ViewModel
     pub ingested_at: String,
 }
 
+impl Formattable for ViewModel {}
+
 impl From<ingestion::Model> for ViewModel
 {
     fn from(model: ingestion::Model) -> Self
@@ -182,11 +185,9 @@ impl CommandHandler for ListIngestion
             return Ok(());
         }
 
-        let table = Table::new(ingestions.iter().map(|i| ViewModel::from(i.clone())))
-            .with(tabled::settings::Style::modern())
-            .to_string();
-
-        println!("{}", table);
+        let view_models: Vec<ViewModel> = ingestions.iter().map(|i| ViewModel::from(i.clone())).collect();
+        let formatted = FormattableVec::new(view_models).format(context.output_format);
+        println!("{}", formatted);
 
         Ok(())
     }

src/lib/mod.rs

@@ -16,14 +16,17 @@ use sea_orm_migration::MigratorTrait;
 use std::env::temp_dir;
 use std::fmt::Debug;
 use std::path::PathBuf;
+use crate::OutputFormat;
 
 pub mod dosage;
 pub mod route_of_administration;
+pub mod output;
 
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone)]
 pub struct Context<'a>
 {
-    pub(crate) database_connection: &'a DatabaseConnection,
+    pub database_connection: &'a sea_orm::DatabaseConnection,
+    pub output_format: OutputFormat,
 }
 
 #[async_trait]
@@ -67,7 +70,6 @@ lazy_static::lazy_static! {
 
         // Try to open database connection
         debug!("Opening database connection to {}", sqlite_path);
-        println!("Connecting into {}", sqlite_path);
 
         match block_on(async { Database::connect(&sqlite_path).await }) {
             Ok(connection) => {

src/lib/output.rs

@@ -0,0 +1,43 @@
+use serde::Serialize;
+use tabled::Table;
+use tabled::Tabled;
+use crate::OutputFormat;
+
+pub trait Formattable: Serialize + Tabled + Sized {
+    fn format(&self, format: OutputFormat) -> String {
+        match format {
+            OutputFormat::Pretty => {
+                Table::new(std::iter::once(self))
+                    .with(tabled::settings::Style::modern())
+                    .to_string()
+            }
+            OutputFormat::Json => {
+                serde_json::to_string_pretty(self).unwrap_or_else(|_| "Error serializing to JSON".to_string())
+            }
+        }
+    }
+}
+
+pub struct FormattableVec<T: Formattable>(Vec<T>);
+
+impl<T: Formattable> FormattableVec<T> {
+    pub fn new(items: Vec<T>) -> Self {
+        Self(items)
+    }
+
+    pub fn format(&self, format: OutputFormat) -> String {
+        match format {
+            OutputFormat::Pretty => {
+                if self.0.is_empty() {
+                    return "No items found.".to_string();
+                }
+                Table::new(&self.0)
+                    .with(tabled::settings::Style::modern())
+                    .to_string()
+            }
+            OutputFormat::Json => {
+                serde_json::to_string_pretty(&self.0).unwrap_or_else(|_| "Error serializing to JSON".to_string())
+            }
+        }
+    }
+} 

src/main.rs

@@ -17,6 +17,7 @@ use lib::DATABASE_CONNECTION;
 use rust_embed::Embed;
 use sea_orm::prelude::async_trait::async_trait;
 use std::string::ToString;
+use atty::Stream;
 
 mod command;
 mod db;
@@ -37,6 +38,14 @@ lazy_static! {
     static ref FIGURE: figlet_rs::FIGure<'static> = FIGFONT.convert("psylog").unwrap();
 }
 
+fn default_output_format() -> OutputFormat {
+    if atty::is(Stream::Stdout) {
+        OutputFormat::Pretty
+    } else {
+        OutputFormat::Json
+    }
+}
+
 #[derive(Parser)]
 #[command(
     version = env!("CARGO_PKG_VERSION"),
@@ -47,10 +56,23 @@ pub struct CLI
 {
     #[command(subcommand)]
     pub command: ApplicationCommands,
+
+    /// Output format for the command results
+    #[arg(short = 'o', long = "output", value_enum, default_value_t = default_output_format())]
+    pub output_format: OutputFormat,
+
     #[command(flatten)]
     verbose: clap_verbosity_flag::Verbosity,
 }
 
+#[derive(clap::ValueEnum, Clone, Debug)]
+pub enum OutputFormat {
+    /// Pretty printed tables
+    Pretty,
+    /// JSON formatted output
+    Json,
+}
+
 fn default_complete_shell() -> clap_complete::Shell
 {
     clap_complete::shells::Shell::from_env().unwrap()
@@ -122,6 +144,7 @@ async fn main()
 
     let context = Context {
         database_connection: &DATABASE_CONNECTION,
+        output_format: cli.output_format,
     };
 
     migrate_database(context.database_connection)

src/substance.rs

@@ -1,5 +1,6 @@
 use crate::lib::CommandHandler;
 use crate::lib::Context;
+use crate::lib::output::{Formattable, FormattableVec};
 use clap::Parser;
 use clap::Subcommand;
 use sea_orm::prelude::async_trait::async_trait;
@@ -19,6 +20,8 @@ pub struct ViewModel
     pub common_names: String,
 }
 
+impl Formattable for ViewModel {}
+
 impl From<SubstanceTable> for ViewModel
 {
     fn from(model: SubstanceTable) -> Self