#!/usr/bin/env bash

##
# NAME
#     tmux-copy-selection - preview and copy stdin to tmux buffer
#
# SYNOPSIS
#     tmux-copy-selection [-h|--help]
#     some-command | tmux-copy-selection
#
# DESCRIPTION
#     This script loads input from standard input and copies it to
#     the tmux buffer using tmux's copy-mode interface.
#
#     It opens a temporary tmux window named "copy-buffer-preview",
#     displays the input using `tmux show-buffer`, enters copy-mode,
#     selects the entire content, copies it, and automatically closes
#     the window and cleans up.
#
#     This script is especially useful when utilities like `xclip`,
#     `xsel`, `pbcopy`, or `wl-copy` are not available in the system,
#     or when you're working in a terminal-only environment without
#     GUI clipboard access.
#
#     The content will be stored in tmux’s internal buffer and can be
#     pasted into any pane using the standard tmux paste keys
#     (usually `prefix + ]`).
#
# OPTIONS
#     -h, --help
#         Show this help message and exit.
#
# EXAMPLES
#     echo "Hello, world" | tmux-copy-selection
#     cat myfile.txt | tmux-copy-selection
#
# REQUIREMENTS
#     - Must be executed inside a tmux session (`$TMUX` must be set).
#     - Tmux must be installed and properly configured.
#
# BEHAVIOR
#     - If not inside a tmux session, the script exits with an error.
#     - Temporarily loads input into the tmux buffer.
#     - Simulates selection and copying via copy-mode.
#     - Deletes the temporary buffer and window after completion.
#
# AUTHOR
#     athesto - https://athesto.github.io

# Help command
[[ "$*" =~ (-h|--help) ]] && sed -n '/^##$/,/^$/ {s/.//;s/.//;p}' "$0" && exit 0

if [ -z "$TMUX" ]; then
  echo "🚫 This script needs a TMUX session to be executed"
  exit 1
fi

WINDOW_NAME="copy-buffer-preview"
CONTENT=$(cat)

printf "%s" "$CONTENT" | tmux load-buffer -
tmux new-window -n "$WINDOW_NAME" "tmux show-buffer; read"


sleep 0.3
tmux copy-mode -t "$WINDOW_NAME"
#tmux send-keys -t "$WINDOW_NAME" -X cursor-left #  sometimes it takes a new line at the end
tmux send-keys -t "$WINDOW_NAME" -X begin-selection
tmux send-keys -t "$WINDOW_NAME" -X history-top
tmux send-keys -t "$WINDOW_NAME" -X copy-selection-and-cancel

PREV_BUFFER=$(tmux list-buffer | head -1 | cut -d: -f1)
tmux delete-buffer -b "$PREV_BUFFER"

tmux kill-window -t "$WINDOW_NAME"