#!/bin/bash

# ==============================================================================
# Script Description:
# This script connects an existing local directory to a remote Git repository.
# 
# Process:
# 1. Initializes a new local Git repository.
# 2. Adds the remote 'origin'.
# 3. Fetches the remote repository data.
# 4. Stages local files to check differences.
# 5. Identifies real changes bypassing the Git --name-only whitespace bug.
# 6. Prompts to override local files if diffs are found.
#
# Updated: Includes intelligent .gitignore handling (local vs remote comparison).
# ==============================================================================

if [ -z "$1" ]; then
    echo "Error: No repository SSH URL provided."
    echo "Usage: $0 <repository-ssh-url>"
    exit 1
fi

REPO_URL=$1
BRANCH="master"

echo "Initializing Git repository..."
git init 

echo "Adding remote 'origin' -> $REPO_URL"
git remote add origin "$REPO_URL"

echo "Fetching from origin..."
git fetch origin

# --- .GITIGNORE LOGIC ---
REMOTE_IGNORE_TEMP=$(mktemp)
if git show "origin/$BRANCH:.gitignore" > "$REMOTE_IGNORE_TEMP" 2>/dev/null; then
    if [ -f .gitignore ]; then
        # Check if local and remote versions are actually different
        if ! diff -q .gitignore "$REMOTE_IGNORE_TEMP" > /dev/null; then
            echo "---"
            echo "NOTICE: .gitignore conflict detected."
            echo "Differences ( - Local / + Remote ):"
            diff -u .gitignore "$REMOTE_IGNORE_TEMP" | tail -n +3
            echo "---"
            read -p "Overwrite local .gitignore with the remote version? (y/N): " ignore_choice
            case "$ignore_choice" in
                [yY]* ) 
                    mv "$REMOTE_IGNORE_TEMP" .gitignore
                    echo "Replaced with remote .gitignore."
                    ;;
                * ) 
                    echo "Keeping local .gitignore. Note: This may cause extra files to show in the diff below."
                    rm "$REMOTE_IGNORE_TEMP"
                    ;;
            esac
        else
            echo "Local and remote .gitignore are identical."
            rm "$REMOTE_IGNORE_TEMP"
        fi
    else
        echo "No local .gitignore found. Applying remote version..."
        mv "$REMOTE_IGNORE_TEMP" .gitignore
    fi
else
    echo "No .gitignore found on remote. Proceeding with existing local state..."
    rm -f "$REMOTE_IGNORE_TEMP"
fi
# ---------------------------------

echo "Staging local files so Git can compare them..."
# Clear cache first to ensure we aren't tracking things the new .gitignore should skip
git rm -r --cached . > /dev/null 2>&1
git add .

echo "Checking for differences (ignoring line-endings and whitespace)..."
if git diff --cached --quiet --ignore-cr-at-eol --ignore-space-at-eol "origin/$BRANCH"; then
    echo "Local folder matches remote origin/$BRANCH exactly."
else
    echo ""
    echo "Differences exist in the following files:"
    
    # We use --numstat instead of --name-only. 
    # Files with only whitespace diffs will output '0 \t 0 \t filename'. 
    # Awk filters out the ones where added ($1) and deleted ($2) are both 0.
    # Note: Binary changes show as '-' rather than '0', which awk will correctly keep. 
    git diff --cached --numstat --ignore-cr-at-eol --ignore-space-at-eol "origin/$BRANCH" | \
    awk -F'\t' '$1!="0" || $2!="0" {print $3}'
    
    echo ""
    read -p "Do you want to discard your local changes and accept the remote version for these files? (y/N): " choice
    case "$choice" in 
        [yY]* ) 
            echo "Accepting remote versions..."
            ;;
        * ) 
            echo "Operation aborted by user."
            echo "You can review full diffs manually by running: git diff --cached --ignore-cr-at-eol --ignore-space-at-eol origin/$BRANCH"
            exit 1
            ;;
    esac
fi

echo "Setting up tracking and aligning with remote..."

# 1. First ensure we are on the correct branch name
git checkout -B "$BRANCH"

# 2. Reset hard FIRST so the branch actually has commits
git reset --hard "origin/$BRANCH"

# 3. NOW set the upstream tracking, since the branch is no longer empty
git branch --set-upstream-to="origin/$BRANCH" "$BRANCH"

echo "Success! The local folder is now completely linked to the remote repository."