context tunnel - bash

tunnel.sh

#!/bin/bash

# ==========================================
# Tunnel Manager for AI Context
# Usage: 
#   ./tunnel.sh link <source_path> [target_name]
#   ./tunnel.sh unlink [target_name]
# ==========================================

COMMAND=$1
DEFAULT_NAME="TEMPLATE"

# Colors for output
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
RED='\033[0;31m'
NC='\033[0m' # No Color

function show_usage {
    echo -e "Usage:"
    echo -e "  ${GREEN}./tunnel.sh link <path-to-folder> [alias-name]${NC}  (Default alias: $DEFAULT_NAME)"
    echo -e "  ${GREEN}./tunnel.sh unlink [alias-name]${NC}                (Default alias: $DEFAULT_NAME)"
    exit 1
}

# Check if command is provided
if [ -z "$COMMAND" ]; then
    show_usage
fi

# ==========================================
# LINK COMMAND
# ==========================================
if [ "$COMMAND" == "link" ]; then
    SOURCE_PATH=$2
    TARGET_NAME=${3:-$DEFAULT_NAME} # Use 3rd arg or default

    # 1. Validate Source
    if [ -z "$SOURCE_PATH" ]; then
        echo -e "${RED}Error: Missing source path.${NC}"
        show_usage
    fi

    if [ ! -d "$SOURCE_PATH" ]; then
        echo -e "${RED}Error: Source directory does not exist: $SOURCE_PATH${NC}"
        exit 1
    fi

    # Convert source to absolute path to prevent broken links
    # (cd to dir, pwd, then jump back)
    ABS_SOURCE_PATH=$(cd "$SOURCE_PATH" && pwd)

    # Check for circular links
    if [ -L "$ABS_SOURCE_PATH" ]; then
        RESOLVED=$(readlink "$ABS_SOURCE_PATH")
        CURRENT_DIR=$(pwd)
        if [[ "$RESOLVED" == *"$CURRENT_DIR"* ]] || [[ "$RESOLVED" == *"$TARGET_NAME"* ]]; then
            echo -e "${RED}Error: Creating this link would form a circular dependency.${NC}"
            exit 1
        fi
    fi

    # 2. Check if Target already exists
    if [ -e "$TARGET_NAME" ]; then
        echo -e "${RED}Error: A file or folder named '$TARGET_NAME' already exists here.${NC}"
        exit 1
    fi

    # 3. Create Symlink
    ln -s "$ABS_SOURCE_PATH" "$TARGET_NAME"
    echo -e "${GREEN}✔ Linked '$TARGET_NAME' -> '$ABS_SOURCE_PATH'${NC}"

    # 4. Handle .gitignore
    if [ ! -f .gitignore ]; then
        touch .gitignore
        echo -e "${YELLOW}Created .gitignore file.${NC}"
    fi

    # Check if entry exists (grep -q is silent)
    if grep -Fxq "$TARGET_NAME" .gitignore; then
        echo -e "${GREEN}✔ '$TARGET_NAME' is already in .gitignore${NC}"
    else
        # Ensure we append to a new line
        # Check if file ends with newline, if not add one
        if [ -s .gitignore ] && [ "$(tail -c1 .gitignore | wc -l)" -eq 0 ]; then
            echo "" >> .gitignore
        fi
        echo "$TARGET_NAME" >> .gitignore
        echo -e "${GREEN}✔ Added '$TARGET_NAME' to .gitignore${NC}"
    fi

# ==========================================
# UNLINK COMMAND
# ==========================================
elif [ "$COMMAND" == "unlink" ]; then
    TARGET_NAME=${2:-$DEFAULT_NAME} # Use 2nd arg or default

    # 1. Validate it exists
    if [ ! -e "$TARGET_NAME" ] && [ ! -L "$TARGET_NAME" ]; then
        echo -e "${RED}Error: '$TARGET_NAME' not found.${NC}"
        exit 1
    fi

    # 2. Validate it is actually a symlink (Safety Check)
    if [ ! -L "$TARGET_NAME" ]; then
        echo -e "${RED}CRITICAL ERROR: '$TARGET_NAME' is a real directory, not a link!${NC}"
        echo -e "This script will NOT delete real directories to prevent data loss."
        exit 1
    fi

    # 3. Remove the link
    # 'unlink' command is safer than 'rm' as it cannot remove directories
    unlink "$TARGET_NAME"
    echo -e "${GREEN}✔ Unlinked '$TARGET_NAME'${NC}"
    
    # Optional: We usually leave the entry in .gitignore as it does no harm,
    # but you could remove it with sed if strict cleanup is needed.

else
    show_usage
fi