#!/usr/bin/env bash
# shellcheck disable=SC2086

# Installs tmux (terminal multiplexer) and deploys .tmux.conf.
# tmux: https://github.com/tmux/tmux
#
# Supported platforms:
#   macOS    : Intel (x86_64), Apple Silicon (arm64) — via Homebrew
#   Linux    : x86_64, aarch64 — via apt, yum, dnf, zypper, or pacman
#
# Prerequisites:
#   - macOS: Homebrew (brew)
#   - Linux: a supported package manager (apt, yum, dnf, zypper, or pacman)

set -euo pipefail

# ────────────────────────────────────────────
# Constants
# ────────────────────────────────────────────
CONF_FILE="${HOME}/.tmux.conf"

# ────────────────────────────────────────────
# Utility functions (all stderr output)
# ────────────────────────────────────────────
info() { echo "[INFO]  $*" >&2; }
warn() { echo "[WARN]  $*" >&2; }
error() {
	echo "[ERROR] $*" >&2
	exit 1
}
success() { echo "[OK]    $*" >&2; }

# ────────────────────────────────────────────
# Detect OS
# ────────────────────────────────────────────
OS="$(uname -s)"
ARCH="$(uname -m)"

case "$OS" in
Darwin | Linux) ;;
*)
	error "Unsupported OS: $OS. This script only supports macOS and Linux."
	;;
esac

# ────────────────────────────────────────────
# Ensure Homebrew is available on macOS
# ────────────────────────────────────────────
ensure_brew() {
	if command -v brew &>/dev/null; then
		return 0
	fi
	info "Homebrew is not installed. Installing Homebrew..."
	/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
	# Add brew to PATH for Apple Silicon
	if [ -d /opt/homebrew/bin ]; then
		export PATH="/opt/homebrew/bin:$PATH"
	fi
	if [ -d /usr/local/bin ]; then
		export PATH="/usr/local/bin:$PATH"
	fi
	command -v brew &>/dev/null || error "Homebrew installation failed. Install it manually: https://brew.sh/"
	success "Homebrew installed"
}

info "Platform: $OS ($ARCH)"

# ────────────────────────────────────────────
# Step 1: Install tmux
# ────────────────────────────────────────────
info "Installing tmux..."

if command -v tmux &>/dev/null; then
	CURRENT_VER="$(tmux -V 2>/dev/null || echo 'unknown')"
	info "tmux is already installed ($CURRENT_VER). Skipping installation."
else
	case "$OS" in
	Darwin)
		ensure_brew
		brew install tmux
		success "tmux installed via Homebrew"
		;;
	Linux)
		if command -v apt-get &>/dev/null; then
			sudo apt-get update -y
			sudo apt-get install -y tmux
			success "tmux installed via apt-get"
		elif command -v dnf &>/dev/null; then
			sudo dnf install -y tmux
			success "tmux installed via dnf"
		elif command -v yum &>/dev/null; then
			sudo yum install -y tmux
			success "tmux installed via yum"
		elif command -v zypper &>/dev/null; then
			sudo zypper -n install tmux
			success "tmux installed via zypper"
		elif command -v pacman &>/dev/null; then
			sudo pacman -S --noconfirm tmux
			success "tmux installed via pacman"
		else
			error "No supported package manager found (apt, dnf, yum, zypper, pacman). Install tmux manually."
		fi
		;;
	esac
fi

# Verify tmux is available
if command -v tmux &>/dev/null; then
	success "tmux is available: $(command -v tmux)"
else
	warn "tmux was not found in PATH after installation. You may need to open a new terminal."
fi

# ────────────────────────────────────────────
# Step 2: Deploy .tmux.conf
# ────────────────────────────────────────────
if [ -f "$CONF_FILE" ]; then
	warn "Existing .tmux.conf found at $CONF_FILE"
	BACKUP="${CONF_FILE}.bak.$(date +%Y%m%d%H%M%S)"
	cp "$CONF_FILE" "$BACKUP"
	info "Backup saved to $BACKUP"
fi

cat >"$CONF_FILE" <<'TMUXCONF'
# .tmux.conf 샘플

# Prefix key 변경 (기본은 Ctrl-b)
set -g prefix C-a
unbind C-b
bind C-a send-prefix

# 창 분할 단축키 변경
bind | split-window -h -c "#{pane_current_path}"
bind - split-window -v -c "#{pane_current_path}"
unbind '"'
unbind %

# 창 이동 단축키 (vim 스타일)
bind h select-pane -L
bind j select-pane -D
bind k select-pane -U
bind l select-pane -R

# 창 전환 단축키
bind -r C-h previous-window
bind -r C-l next-window

# 창 재정렬
bind Space next-layout

# 창 회전
bind o rotate-window

# 창 이름 변경
bind , command-prompt "rename-window %%"

# 창 닫기
bind & kill-window

# 세션 재시작
bind r source-file ~/.tmux.conf \; display "Reloaded!"

# 상태 표시줄 설정 (색상 설정 비활성화)
#set -g status-bg colour235
#set -g status-fg colour136
set -g status-left-length 40
set -g status-right-length 40
set -g status-interval 5
set -g history-limit 10000

# 상태 표시줄 왼쪽 내용 (색상 설정 비활성화)
#set -g status-left '#[fg=green]#S #[fg=yellow]#H'

# 상태 표시줄 오른쪽 내용 (색상 설정 비활성화)
#set -g status-right '#[fg=cyan]%Y-%m-%d #[fg=green]%H:%M:%S'

# 활성 창 스타일
#set -g window-active-style 'fg=colour250,bg=colour232'

# 비활성 창 스타일
#set -g window-style 'fg=colour247,bg=colour236'

# 패널 테두리 색상 (색상 설정 비활성화)
#set -g pane-border-fg colour238
#set -g pane-active-border-fg colour51
#set-option -g pane-border-style 'fg=colour244'
#set-option -g pane-active-border-style 'fg=colour77'

# 복사 모드에서 vi 키 바인딩 사용
setw -g mode-keys vi

# 마우스 지원 활성화
set -g mouse on

# 256색 지원 (비활성화)
#set -g default-terminal "screen-256color"

# for pi
set -g extended-keys on
TMUXCONF

success ".tmux.conf deployed to $CONF_FILE"

# ────────────────────────────────────────────
# Step 3: Post-install notes
# ────────────────────────────────────────────
info ""
info "=================================================="
success "tmux installation complete!"
info "=================================================="
info ""
info "Getting started:"
info "  tmux                    - Start a new session"
info "  tmux new -s <name>      - Start a named session"
info "  tmux attach -t <name>   - Attach to a session"
info "  tmux ls                 - List sessions"
info ""
info "Key bindings (customized via .tmux.conf):"
info "  Ctrl-a |        - Split horizontally"
info "  Ctrl-a -        - Split vertically"
info "  Ctrl-a h/j/k/l  - Navigate panes (vim-style)"
info "  Ctrl-a r         - Reload .tmux.conf"
info ""
info "Config file: $CONF_FILE"