From 9fd5cf781ad3bc47890ecd70b14d49bb493ace64 Mon Sep 17 00:00:00 2001
From: Eli Ribble <eli@theribbles.org>
Date: Wed, 12 Mar 2025 09:25:31 -0700
Subject: [PATCH] Add custom fish shell that shows whether I'm in nix-shell

---
 nalai/etc/nixos/configuration.nix             |   1 +
 .../config/fish/functions/fish_prompt.fish    | 151 ++++++++++++++++++
 2 files changed, 152 insertions(+)
 create mode 100644 nalai/etc/nixos/home/eliribble/config/fish/functions/fish_prompt.fish

diff --git a/nalai/etc/nixos/configuration.nix b/nalai/etc/nixos/configuration.nix
index a6c529a..c94d4bf 100644
--- a/nalai/etc/nixos/configuration.nix
+++ b/nalai/etc/nixos/configuration.nix
@@ -112,6 +112,7 @@
     # The home.stateVersion option does not have a default and must be set
     home.stateVersion = "24.11";
     home.username = "eliribble";
+    home.file.".config/fish/functions/fish_prompt.fish".source = ./home/eliribble/config/fish/functions/fish_prompt.fish;
     home.file.".config/nvim/after/ftplugin/html.vim".source = ./home/eliribble/config/nvim/after/ftplugin/html.vim;
     home.file.".config/nvim/after/ftplugin/go.vim".source = ./home/eliribble/config/nvim/after/ftplugin/go.vim;
     home.file.".config/tmux/tmux.conf".source = ./home/eliribble/config/tmux/tmux.conf;
diff --git a/nalai/etc/nixos/home/eliribble/config/fish/functions/fish_prompt.fish b/nalai/etc/nixos/home/eliribble/config/fish/functions/fish_prompt.fish
new file mode 100644
index 0000000..1bcbff8
--- /dev/null
+++ b/nalai/etc/nixos/home/eliribble/config/fish/functions/fish_prompt.fish
@@ -0,0 +1,151 @@
+set -l nix_shell_info (
+if test -n "$IN_NIX_SHELL"
+echo -n "<nix-shell> "
+end
+)
+
+# Based on the 'nim' prompt from
+# https://github.com/fish-shell/fish-shell/blob/master/share/tools/web_config/sample_prompts/nim.fish
+function fish_prompt
+    # This prompt shows:
+    # - green lines if the last return command is OK, red otherwise
+    # - your user name, in red if root or yellow otherwise
+    # - your hostname, in cyan if ssh or blue otherwise
+    # - the current path (with prompt_pwd)
+    # - date +%X
+    # - the current virtual environment, if any
+    # - the current git status, if any, with fish_git_prompt
+    # - the current battery state, if any, and if your power cable is unplugged, and if you have "acpi"
+    # - current background jobs, if any
+
+    # It goes from:
+    # ┬─[nim@Hattori:~]─[11:39:00]
+    # ╰─>$ echo here
+
+    # To:
+    # ┬─[nim@Hattori:~/w/dashboard]─[11:37:14]─[V:django20]─[G:master↑1|●1✚1…1]─[B:85%, 05:41:42 remaining]
+    # │ 2    15054    0%    arrêtée    sleep 100000
+    # │ 1    15048    0%    arrêtée    sleep 100000
+    # ╰─>$ echo there
+
+    set -l retc red
+    test $status = 0; and set retc green
+
+    set -q __fish_git_prompt_showupstream
+    or set -g __fish_git_prompt_showupstream auto
+
+    function _nim_prompt_wrapper
+        set retc $argv[1]
+        set -l field_name $argv[2]
+        set -l field_value $argv[3]
+
+        set_color normal
+        set_color $retc
+        echo -n '─'
+        set_color -o green
+        echo -n '['
+        set_color normal
+        test -n $field_name
+        and echo -n $field_name:
+        set_color $retc
+        echo -n $field_value
+        set_color -o green
+        echo -n ']'
+    end
+
+    set_color $retc
+    echo -n '┬─'
+    set_color -o green
+    echo -n [
+
+    if functions -q fish_is_root_user; and fish_is_root_user
+        set_color -o red
+    else
+        set_color -o yellow
+    end
+
+    echo -n $USER
+    set_color -o white
+    echo -n @
+
+    if test -z "$SSH_CLIENT"
+        set_color -o blue
+    else
+        set_color -o cyan
+    end
+
+    echo -n (prompt_hostname)
+    set_color -o white
+    echo -n :(prompt_pwd)
+    set_color -o green
+    echo -n ']'
+
+    # Date
+    _nim_prompt_wrapper $retc '' (date +%X)
+
+    # Vi-mode
+    # The default mode prompt would be prefixed, which ruins our alignment.
+    function fish_mode_prompt
+    end
+
+    if test "$fish_key_bindings" = fish_vi_key_bindings
+        or test "$fish_key_bindings" = fish_hybrid_key_bindings
+        set -l mode
+        switch $fish_bind_mode
+            case default
+                set mode (set_color --bold red)N
+            case insert
+                set mode (set_color --bold green)I
+            case replace_one
+                set mode (set_color --bold green)R
+                echo '[R]'
+            case replace
+                set mode (set_color --bold cyan)R
+            case visual
+                set mode (set_color --bold magenta)V
+        end
+        set mode $mode(set_color normal)
+        _nim_prompt_wrapper $retc '' $mode
+    end
+
+    # Virtual Environment
+    set -q VIRTUAL_ENV_DISABLE_PROMPT
+    or set -g VIRTUAL_ENV_DISABLE_PROMPT true
+    set -q VIRTUAL_ENV
+    and _nim_prompt_wrapper $retc V (path basename "$VIRTUAL_ENV")
+
+    # nix-shell
+    if test -n "$IN_NIX_SHELL"
+      echo -n " <nix-shell> "
+    end
+
+    # git
+    set -l prompt_git (fish_git_prompt '%s')
+    test -n "$prompt_git"
+    and _nim_prompt_wrapper $retc G $prompt_git
+
+    # Battery status
+    type -q acpi
+    and acpi -a 2>/dev/null | string match -rq off
+    and _nim_prompt_wrapper $retc B (acpi -b | cut -d' ' -f 4-)
+
+    # New line
+    echo
+
+    # Background jobs
+    set_color normal
+
+    for job in (jobs)
+        set_color $retc
+        echo -n '│ '
+        set_color brown
+        echo $job
+    end
+
+    set_color normal
+    set_color $retc
+    echo -n '╰─>'
+    set_color -o red
+    echo -n '$ '
+    set_color normal
+end