enable logging with CL argument -l --log. Nothing is logged otherwise

6 files changed, 40 insertions, 13 deletions

diff --git a/development.md b/development.md
index be82c96..7acf515 100644
--- a/development.md
+++ b/development.md
@@ -725,6 +725,7 @@ New view: Tree ! Toggle with 't', fold with 'z'. Navigate normally.
 - Configurable cli applications. See `~/fm/cli.yaml`
 - Simplify tui config files. Remove `cwd` boolean parameter. Doesn't break old config files.
 - Display the number of entries as the size of a directory instead of '-'. Might affect performance for very large directories.
+- Enable logging with `-l` or `--log`. Nothing is logged anywhere without this flag.
 
 #### Changelog
 
@@ -754,7 +755,7 @@ New view: Tree ! Toggle with 't', fold with 'z'. Navigate normally.
 - [x] rename Action::Command to Action::Action since it's what it does
 - [x] use number of files for dir size
 - [x] rename Goto Mode to cd to allow `:` then `cd`
-- [ ] optionable logging
+- [x] optionable logging
 - [ ] display number of matches while searching
 - [x] FIX: Filter isn't shown and does nothing in tree mode
 
diff --git a/readme.md b/readme.md
index f0a3fc5..882f96b 100644
--- a/readme.md
+++ b/readme.md
@@ -9,7 +9,7 @@
 [docrs]: https://docs.rs/fm-tui/0.1.24
 
 ```
-A TUI file manager inspired by dired and ranger
+ A TUI file manager inspired by dired and ranger
 
 Usage: fm [OPTIONS]
 
@@ -17,6 +17,7 @@ Options:
   -p, --path <PATH>      Starting path. directory or file [default: .]
   -s, --server <SERVER>  Nvim server [default: ]
   -A, --all              Display all files (hidden)
+  -l, --log              Enable logging
   -h, --help             Print help
   -V, --version          Print version
 ```
@@ -170,6 +171,15 @@ Expansions :
 - %n : selected filename
 - %d : current directory
 
+### Logging
+
+With `-l` or `--log`, logs are enabled. They are disabled by default.
+
+Critical actions will be logged to `~/.config/fm/log/fm.log` and actions affecting the file tree will be logged to `~/.config/fm/log/action_logger.log`.
+
+The last action is displayed at the bottom of the screen and can be read with `Alt+l` like a preview.
+Those logs can be seen even if logging is disabled, it just won't be up to date.
+
 ### More
 
 - Copy a filename/filepath to clipboard with Ctrl+n, Ctrl+p
diff --git a/src/app/tab.rs b/src/app/tab.rs
index b978b9f..a92febb 100644
--- a/src/app/tab.rs
+++ b/src/app/tab.rs
@@ -658,7 +658,8 @@ impl Tab {
 
     /// Move the preview to the bottom
     pub fn preview_go_bottom(&mut self) {
-        self.window.scroll_to(self.preview.len() - 1)
+        self.window
+            .scroll_to(self.preview.len().checked_sub(1).unwrap_or_default())
     }
 
     /// Move 30 lines up or an image in Ueberzug.
diff --git a/src/event/event_exec.rs b/src/event/event_exec.rs
index d894d62..46daeb4 100644
--- a/src/event/event_exec.rs
+++ b/src/event/event_exec.rs
@@ -379,7 +379,9 @@ impl EventAction {
 
     /// Display the last actions impacting the file tree
     pub fn log(tab: &mut Tab) -> Result<()> {
-        let log = read_log()?;
+        let Ok(log) = read_log() else {
+            return Ok(());
+        };
         tab.set_display_mode(Display::Preview);
         tab.preview = Preview::log(log);
         tab.window.reset(tab.preview.len());
diff --git a/src/io/args.rs b/src/io/args.rs
index 7d4ac4f..b594699 100644
--- a/src/io/args.rs
+++ b/src/io/args.rs
@@ -15,4 +15,8 @@ pub struct Args {
     /// Display all files (hidden)
     #[arg(short = 'A', long, default_value_t = false)]
     pub all: bool,
+
+    /// Enable logging
+    #[arg(short = 'l', long, default_value_t = false)]
+    pub log: bool,
 }
diff --git a/src/io/log.rs b/src/io/log.rs
index 551f3d7..388e17f 100644
--- a/src/io/log.rs
+++ b/src/io/log.rs
@@ -1,27 +1,36 @@
 use std::sync::RwLock;
 
 use anyhow::Result;
+use clap::Parser;
 use lazy_static::lazy_static;
 use log4rs;
 
 use crate::common::extract_lines;
 use crate::common::{ACTION_LOG_PATH, LOG_CONFIG_PATH};
-
-// static ENV_HOME: &str = "$ENV{HOME}";
+use crate::io::Args;
 
 /// Set the logs.
+/// First we read the `-l` `--log` command line argument which default to false.
+///
+/// If it's false, nothing is done and we return.
+/// No logger is set, nothing is logged.
+///
+/// If it's true :
 /// The configuration is read from a config file defined in `LOG_CONFIG_PATH`
 /// It's a YAML file which defines 2 logs:
 /// - a normal one used directly with the macros like `log::info!(...)`, used for debugging
 /// - a special one used with `log::info!(target: "special", ...)` to be displayed in the application
 pub fn set_loggers() -> Result<()> {
-    log4rs::init_file(
-        shellexpand::tilde(LOG_CONFIG_PATH).as_ref(),
-        Default::default(),
-    )?;
-    // clear_useless_env_home()?;
-
-    log::info!("fm is starting");
+    let args = Args::parse();
+    if args.log {
+        log4rs::init_file(
+            shellexpand::tilde(LOG_CONFIG_PATH).as_ref(),
+            Default::default(),
+        )?;
+        // clear_useless_env_home()?;
+
+        log::info!("fm is starting with logs enabled");
+    }
     Ok(())
 }