#!/bin/bash

# Get the absolute path to the project directory
PROJECT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
CHALLENGE_DIR=~/challenge

# Colors for output
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
RED='\033[0;31m'
NC='\033[0m'

# Error handling
set -o errexit  # Exit on error
set -o nounset  # Exit on undefined variable
set -o pipefail # Exit on pipe failure

# Trap errors and provide error message
trap 'echo -e "${RED}Error: Command failed at line $LINENO${NC}" >&2' ERR

# Function to check if command exists
check_command() {
    if ! command -v "$1" &>/dev/null; then
        echo -e "${RED}Error: Required command '$1' not found${NC}"
        return 1
    fi
}

# Function to check required commands
check_requirements() {
    local required_commands=("find" "grep" "awk" "sed" "mkdir" "chmod" "touch")
    local missing_commands=()

    for cmd in "${required_commands[@]}"; do
        if ! check_command "$cmd"; then
            missing_commands+=("$cmd")
        fi
    done

    if [[ ${#missing_commands[@]} -gt 0 ]]; then
        echo -e "${RED}Error: Missing required commands: ${missing_commands[*]}${NC}"
        return 1
    fi
    return 0
}

# Function to clean up previous environment
cleanup_environment() {
    echo -e "${BLUE}Cleaning up previous environment...${NC}"
    if [[ -d "$CHALLENGE_DIR" ]]; then
        if ! rm -rf "$CHALLENGE_DIR" 2>/dev/null; then
            echo -e "${RED}Error: Failed to remove directory: $CHALLENGE_DIR${NC}"
            echo -e "${YELLOW}Tip: Check if you have proper permissions${NC}"
            return 1
        fi
        echo -e "${GREEN}Previous environment cleaned up${NC}"
    fi
}

# Function to setup the environment
setup_environment() {
    echo -e "${BLUE}Setting up challenge environment...${NC}"
    
    # Check requirements first
    if ! check_requirements; then
        echo -e "${RED}Error: Setup failed - missing requirements${NC}"
        return 1
    fi
    
    # Clean up first
    cleanup_environment
    
    # Create directory structure with error checking
    local dirs=(
        "$CHALLENGE_DIR"/{files,backup,temp}
        "$CHALLENGE_DIR/.tracking/data"
    )
    
    for dir in "${dirs[@]}"; do
        if ! mkdir -p "$dir"; then
            echo -e "${RED}Error: Failed to create directory: $dir${NC}"
            return 1
        fi
    done
    
    # Create project directories with error checking
    for i in {1..5}; do
        local project_dirs=(
            "$CHALLENGE_DIR/files/project$i"/{src,config,logs,data}
        )
        for dir in "${project_dirs[@]}"; do
            if ! mkdir -p "$dir"; then
                echo -e "${RED}Error: Failed to create project directory: $dir${NC}"
                return 1
            fi
        done
    done
    
    # Copy setup scripts with error checking
    if ! cp "$PROJECT_DIR"/setup/*.sh "$CHALLENGE_DIR/.tracking/" 2>/dev/null; then
        echo -e "${RED}Error: Failed to copy setup scripts${NC}"
        echo -e "${YELLOW}Tip: Check if setup scripts exist in: $PROJECT_DIR/setup/${NC}"
        return 1
    fi
    
    # Set permissions with error checking
    if ! chmod +x "$CHALLENGE_DIR/.tracking/"*.sh 2>/dev/null; then
        echo -e "${RED}Error: Failed to set script permissions${NC}"
        return 1
    fi
    
    # Initialize tracking files with error checking
    local data_dir="$CHALLENGE_DIR/.tracking/data"
    local tracking_files=(progress score challenge commands time hints_used achievements attempts)
    
    for file in "${tracking_files[@]}"; do
        if ! touch "$data_dir/$file.csv" 2>/dev/null; then
            echo -e "${RED}Error: Failed to create tracking file: $file.csv${NC}"
            return 1
        fi
    done
    
    echo -e "${GREEN}Environment setup complete!${NC}"
}

# Function to validate challenge ID
validate_challenge_id() {
    local id=$1
    if [[ ! $id =~ ^[1-9]\.[1-5]$ ]]; then
        echo -e "${RED}Error: Invalid challenge ID format${NC}"
        echo -e "${YELLOW}Tip: Challenge ID should be in format 'level.number' (e.g., 1.1)${NC}"
        return 1
    fi
}

# Function to start a challenge
start_challenge() {
    local challenge_id=$1
    
    # Validate challenge ID
    if ! validate_challenge_id "$challenge_id"; then
        return 1
    fi
    
    # Source required scripts with error checking
    local required_scripts=(common.sh challenges.sh)
    for script in "${required_scripts[@]}"; do
        if ! source "$CHALLENGE_DIR/.tracking/$script" 2>/dev/null; then
            echo -e "${RED}Error: Required script not found: $script${NC}"
            echo -e "${YELLOW}Running setup first...${NC}"
            setup_environment
            if ! source "$CHALLENGE_DIR/.tracking/$script" 2>/dev/null; then
                echo -e "${RED}Error: Failed to source $script even after setup${NC}"
                return 1
            fi
        fi
    done
    
    clear
    echo -e "${GREEN}🎮 Command Line Mastery Challenge${NC}"
    echo "=============================="
    
    # Setup challenge environment with error checking
    if ! get_challenge_details "$challenge_id" 2>/dev/null; then
        echo -e "${RED}Error: Challenge $challenge_id not found${NC}"
        echo -e "${YELLOW}Available challenges:${NC}"
        list_challenges
        return 1
    fi
    
    if ! bash "$CHALLENGE_DIR/.tracking/level1-setup.sh" 2>/dev/null; then
        echo -e "${RED}Error: Failed to setup challenge environment${NC}"
        echo -e "${YELLOW}Try running: $0 clean && $0 setup${NC}"
        return 1
    fi
    
    # Record challenge start with error checking
    local start_time=$(date +%s)
    if ! echo "$challenge_id,$start_time" > "$CHALLENGE_DIR/.tracking/current_challenge" 2>/dev/null; then
        echo -e "${RED}Error: Failed to record challenge start${NC}"
        return 1
    fi
    
    # Create command aliases
    alias verify="$CHALLENGE_DIR/.tracking/verify-challenge.sh"
    alias hint="$CHALLENGE_DIR/.tracking/show-hint.sh"
    alias status="$CHALLENGE_DIR/.tracking/track-progress.sh"
    
    echo -e "\n${GREEN}Challenge ready!${NC}"
    echo -e "Commands available:"
    echo -e "  ${YELLOW}verify${NC} - Check your solution"
    echo -e "  ${YELLOW}hint${NC}   - Get a hint"
    echo -e "  ${YELLOW}status${NC} - Show progress"
}

# Function to show help
show_help() {
    cat << EOF
Usage: $0 [command] [options]

Commands:
    start <challenge-id>  Start a specific challenge
    list                 List available challenges
    setup                Setup/reset the environment
    clean                Remove all challenge files
    help                 Show this help message

Examples:
    $0 setup            # First time setup
    $0 clean            # Remove all challenge files
    $0 list             # Show available challenges
    $0 start 1.1        # Start challenge 1.1
EOF
}

# Main execution with error handling
main() {
    if [[ $# -eq 0 ]]; then
        show_help
        return 0
    fi

    case "$1" in
        "setup")
            setup_environment
            ;;
        "clean")
            cleanup_environment
            ;;
        "start")
            if [[ -z "${2:-}" ]]; then
                echo -e "${RED}Error: Please specify a challenge ID${NC}"
                echo "Example: $0 start 1.1"
                return 1
            fi
            start_challenge "$2"
            ;;
        "list")
            if [[ ! -f "$CHALLENGE_DIR/.tracking/challenges.sh" ]]; then
                setup_environment
            fi
            if ! source "$CHALLENGE_DIR/.tracking/challenges.sh" 2>/dev/null; then
                echo -e "${RED}Error: Failed to load challenges${NC}"
                return 1
            fi
            list_challenges
            ;;
        "help"|"--help"|"-h")
            show_help
            ;;
        *)
            echo -e "${RED}Unknown command: $1${NC}"
            show_help
            return 1
            ;;
    esac
}

# Run main with error handling
if ! main "${@:-}"; then
    echo -e "${RED}Command failed. See errors above.${NC}"
    exit 1
fi