#!/bin/bash

# gp - Git Push with AI-generated commit messages
# Improved version with better error handling, safety checks, and functionality

set -euo pipefail

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Function to print colored output
print_info() { echo -e "${BLUE}[INFO]${NC} $1"; }
print_success() { echo -e "${GREEN}[SUCCESS]${NC} $1"; }
print_warning() { echo -e "${YELLOW}[WARNING]${NC} $1"; }
print_error() { echo -e "${RED}[ERROR]${NC} $1"; }

# Function to show help
show_help() {
    cat << 'EOF'
gp - Git Push with smart commit messages

USAGE:
    gp [options] [message]

OPTIONS:
    -h, --help      Show this help message
    -n, --dry-run   Show what would be committed without actually doing it
    -f, --force     Skip safety checks (use with caution)
    -b, --branch    Specify branch to push to (default: current branch)
    -a, --add-all   Add all files including untracked (default: only staged + modified)

ARGUMENTS:
    message         Optional custom commit message (overrides auto-generation)

EXAMPLES:
    gp                          # Auto-generate commit message and push
    gp "Fix bug in parser"      # Use custom commit message
    gp --dry-run                # Preview what would be committed
    gp -b develop               # Push to develop branch instead of current

EOF
}

# Function to generate commit message based on changes
generate_commit_message() {
    local files_changed=$(git diff --cached --name-only)
    local files_count=$(echo "$files_changed" | wc -l)
    
    if [ -z "$files_changed" ]; then
        files_changed=$(git diff --name-only)
        files_count=$(echo "$files_changed" | wc -l)
    fi
    
    # If add-all is enabled, also include untracked files
    if [ "$ADD_ALL" = true ] && [ -z "$files_changed" ]; then
        files_changed=$(git ls-files --others --exclude-standard)
        files_count=$(echo "$files_changed" | wc -l)
    fi
    
    if [ -z "$files_changed" ]; then
        echo "No changes to commit"
        return 1
    fi
    
    # Generate smart commit message based on file types and changes
    local has_source_files=false
    local has_config_files=false
    local has_docs=false
    local has_tests=false
    local message=""
    
    while IFS= read -r file; do
        [ -z "$file" ] && continue
        
        case "$file" in
            *.cpp|*.hpp|*.c|*.h|*.js|*.ts|*.py|*.go|*.rs|*.java)
                has_source_files=true
                ;;
            *.json|*.yml|*.yaml|*.toml|*.ini|*.conf|CMakeLists.txt|Makefile)
                has_config_files=true
                ;;
            *.md|*.txt|*.rst|docs/*|README*)
                has_docs=true
                ;;
            *test*|*spec*|test/*|tests/*)
                has_tests=true
                ;;
        esac
    done <<< "$files_changed"
    
    # Create descriptive commit message
    if [ "$files_count" -eq 1 ]; then
        local single_file=$(echo "$files_changed" | head -1)
        local change_type=$(git diff --cached --name-status "$single_file" 2>/dev/null || git diff --name-status "$single_file")
        case "${change_type:0:1}" in
            A) message="Add $single_file" ;;
            M) message="Update $single_file" ;;
            D) message="Remove $single_file" ;;
            R) message="Rename $single_file" ;;
            *) message="Modify $single_file" ;;
        esac
    else
        local prefix=""
        if $has_tests; then
            prefix="test: "
        elif $has_docs; then
            prefix="docs: "
        elif $has_config_files; then
            prefix="config: "
        elif $has_source_files; then
            prefix="feat: "
        fi
        
        message="${prefix}Update $files_count files"
    fi
    
    echo "$message"
}

# Function to check if we're in a git repository
check_git_repo() {
    if ! git rev-parse --git-dir >/dev/null 2>&1; then
        print_error "Not in a git repository"
        exit 1
    fi
}

# Function to check for uncommitted changes
check_for_changes() {
    if git diff --cached --quiet && git diff --quiet; then
        if [ "$ADD_ALL" = false ]; then
            print_warning "No staged changes found"
            print_info "Use 'gp -a' to add all files, or stage changes first with 'git add'"
            exit 0
        fi
    fi
}

# Function to show what would be committed
show_status() {
    print_info "Current branch: $(git branch --show-current)"
    print_info "Repository: $(git remote get-url origin 2>/dev/null || echo 'No remote')"
    echo
    
    if git diff --cached --quiet; then
        print_info "Staged changes: None"
        if ! git diff --quiet; then
            print_info "Modified files (unstaged):"
            git diff --name-only | sed 's/^/  /'
        fi
    else
        print_info "Staged changes:"
        git diff --cached --name-only | sed 's/^/  /'
    fi
    
    if [ "$ADD_ALL" = true ]; then
        local untracked=$(git ls-files --others --exclude-standard)
        if [ -n "$untracked" ]; then
            print_info "Untracked files (will be added):"
            echo "$untracked" | sed 's/^/  /'
        fi
    fi
}

# Function to perform the actual commit and push
do_commit_and_push() {
    local commit_msg="$1"
    local target_branch="$2"
    
    # Add files if requested
    if [ "$ADD_ALL" = true ]; then
        print_info "Adding all files..."
        git add .
    fi
    
    # Commit
    print_info "Committing with message: '$commit_msg'"
    git commit -m "$commit_msg"
    
    # Push
    print_info "Pushing to $target_branch..."
    if git push origin "$target_branch"; then
        print_success "Successfully pushed to origin/$target_branch"
    else
        print_error "Failed to push to origin/$target_branch"
        print_info "You may need to pull first: git pull origin $target_branch"
        exit 1
    fi
}

# Default values
DRY_RUN=false
FORCE=false
ADD_ALL=false
CUSTOM_MESSAGE=""
TARGET_BRANCH=""

# Handle special commands first
case "${1:-}" in
    autocomplete)
        shift
        autocomplete "$@"
        exit 0
        ;;
    version)
        echo "gp version 2.0.0"
        exit 0
        ;;
esac

# Parse command line arguments
while [[ $# -gt 0 ]]; do
    case $1 in
        -h|--help)
            show_help
            exit 0
            ;;
        -n|--dry-run)
            DRY_RUN=true
            shift
            ;;
        -f|--force)
            FORCE=true
            shift
            ;;
        -a|--add-all)
            ADD_ALL=true
            shift
            ;;
        -b|--branch)
            TARGET_BRANCH="$2"
            shift 2
            ;;
        -*)
            print_error "Unknown option: $1"
            echo "Use 'gp --help' for usage information"
            exit 1
            ;;
        *)
            CUSTOM_MESSAGE="$1"
            shift
            ;;
    esac
done

# Main execution
main() {
    # Safety checks
    check_git_repo
    
    # Set target branch if not specified
    if [ -z "$TARGET_BRANCH" ]; then
        TARGET_BRANCH=$(git branch --show-current)
    fi
    
    # Check for changes
    check_for_changes
    
    # Show current status
    show_status
    echo
    
    # Generate or use custom commit message
    if [ -n "$CUSTOM_MESSAGE" ]; then
        commit_message="$CUSTOM_MESSAGE"
        print_info "Using custom commit message: '$commit_message'"
    else
        print_info "Generating commit message..."
        commit_message=$(generate_commit_message)
        if [ $? -ne 0 ]; then
            print_error "Failed to generate commit message"
            exit 1
        fi
        print_info "Generated commit message: '$commit_message'"
    fi
    
    # Dry run mode
    if [ "$DRY_RUN" = true ]; then
        print_warning "DRY RUN MODE - No changes will be made"
        print_info "Would commit with message: '$commit_message'"
        print_info "Would push to: origin/$TARGET_BRANCH"
        exit 0
    fi
    
    # Safety confirmation (unless forced)
    if [ "$FORCE" = false ]; then
        echo
        read -p "Proceed with commit and push? [y/N] " -n 1 -r
        echo
        if [[ ! $REPLY =~ ^[Yy]$ ]]; then
            print_info "Aborted by user"
            exit 0
        fi
    fi
    
    # Execute the commit and push
    do_commit_and_push "$commit_message" "$TARGET_BRANCH"
}

# Autocomplete function for bash
autocomplete() {
    local args=("$@")
    if [ ${#args[@]} -eq 0 ]; then
        echo "--help"
        echo "--dry-run"
        echo "--force"
        echo "--add-all"
        echo "--branch"
        echo "-h"
        echo "-n"
        echo "-f"
        echo "-a"
        echo "-b"
    fi
}

# Run main function
main "$@"