#!/bin/bash
# Docker Entrypoint Script for Trasabilitate Application
# Handles initialization, health checks, and graceful startup

set -e  # Exit on error
set -u  # Exit on undefined variable
set -o pipefail  # Exit on pipe failure

# ============================================================================
# LOGGING UTILITIES
# ============================================================================
log_info() {
    echo "[$(date +'%Y-%m-%d %H:%M:%S')] ℹ️  INFO: $*"
}

log_success() {
    echo "[$(date +'%Y-%m-%d %H:%M:%S')] ✅ SUCCESS: $*"
}

log_warning() {
    echo "[$(date +'%Y-%m-%d %H:%M:%S')] ⚠️  WARNING: $*"
}

log_error() {
    echo "[$(date +'%Y-%m-%d %H:%M:%S')] ❌ ERROR: $*" >&2
}

# ============================================================================
# ENVIRONMENT VALIDATION
# ============================================================================
validate_environment() {
    log_info "Validating environment variables..."
    
    local required_vars=("DB_HOST" "DB_PORT" "DB_NAME" "DB_USER" "DB_PASSWORD")
    local missing_vars=()
    
    for var in "${required_vars[@]}"; do
        if [ -z "${!var:-}" ]; then
            missing_vars+=("$var")
        fi
    done
    
    if [ ${#missing_vars[@]} -gt 0 ]; then
        log_error "Missing required environment variables: ${missing_vars[*]}"
        exit 1
    fi
    
    log_success "Environment variables validated"
}

# ============================================================================
# DATABASE CONNECTION CHECK
# ============================================================================
wait_for_database() {
    local max_retries="${DB_MAX_RETRIES:-60}"
    local retry_interval="${DB_RETRY_INTERVAL:-2}"
    local retry_count=0
    
    log_info "Waiting for MariaDB to be ready..."
    log_info "Database: ${DB_USER}@${DB_HOST}:${DB_PORT}/${DB_NAME}"
    
    while [ $retry_count -lt $max_retries ]; do
        if python3 << END
import mariadb
import sys

try:
    conn = mariadb.connect(
        user="${DB_USER}",
        password="${DB_PASSWORD}",
        host="${DB_HOST}",
        port=int(${DB_PORT}),
        database="${DB_NAME}",
        connect_timeout=5
    )
    conn.close()
    sys.exit(0)
except Exception as e:
    print(f"Connection failed: {e}")
    sys.exit(1)
END
        then
            log_success "Database connection established!"
            return 0
        fi
        
        retry_count=$((retry_count + 1))
        log_warning "Database not ready (attempt ${retry_count}/${max_retries}). Retrying in ${retry_interval}s..."
        sleep $retry_interval
    done
    
    log_error "Failed to connect to database after ${max_retries} attempts"
    exit 1
}

# ============================================================================
# DIRECTORY SETUP
# ============================================================================
setup_directories() {
    log_info "Setting up application directories..."
    
    # Create necessary directories
    mkdir -p /app/instance
    mkdir -p /srv/quality_recticel/logs
    
    # Set proper permissions (if not running as root)
    if [ "$(id -u)" != "0" ]; then
        log_info "Running as non-root user (UID: $(id -u))"
    fi
    
    log_success "Directories configured"
}

# ============================================================================
# DATABASE CONFIGURATION
# ============================================================================
create_database_config() {
    log_info "Creating database configuration file..."
    
    local config_file="/app/instance/external_server.conf"
    
    cat > "$config_file" << EOF
# Database Configuration - Generated on $(date)
server_domain=${DB_HOST}
port=${DB_PORT}
database_name=${DB_NAME}
username=${DB_USER}
password=${DB_PASSWORD}
EOF
    
    # Secure the config file (contains password)
    chmod 600 "$config_file"
    
    log_success "Database configuration created at: $config_file"
}

# ============================================================================
# DATABASE INITIALIZATION
# ============================================================================
initialize_database() {
    if [ "${INIT_DB:-false}" = "true" ]; then
        log_info "Initializing database schema..."
        
        if python3 /app/app/db_create_scripts/setup_complete_database.py; then
            log_success "Database schema initialized successfully"
        else
            local exit_code=$?
            if [ $exit_code -eq 0 ] || [ "${IGNORE_DB_INIT_ERRORS:-false}" = "true" ]; then
                log_warning "Database initialization completed with warnings (exit code: $exit_code)"
            else
                log_error "Database initialization failed (exit code: $exit_code)"
                exit 1
            fi
        fi
    else
        log_info "Skipping database initialization (INIT_DB=${INIT_DB:-false})"
    fi
}

# ============================================================================
# DATABASE SEEDING
# ============================================================================
seed_database() {
    if [ "${SEED_DB:-false}" = "true" ]; then
        log_info "Seeding database with initial data..."
        
        if python3 /app/seed.py; then
            log_success "Database seeded successfully"
        else
            local exit_code=$?
            if [ "${IGNORE_SEED_ERRORS:-false}" = "true" ]; then
                log_warning "Database seeding completed with warnings (exit code: $exit_code)"
            else
                log_error "Database seeding failed (exit code: $exit_code)"
                exit 1
            fi
        fi
    else
        log_info "Skipping database seeding (SEED_DB=${SEED_DB:-false})"
    fi
}

# ============================================================================
# HEALTH CHECK
# ============================================================================
run_health_check() {
    if [ "${SKIP_HEALTH_CHECK:-false}" = "true" ]; then
        log_info "Skipping pre-startup health check"
        return 0
    fi
    
    log_info "Running application health checks..."
    
    # Check Python imports
    if ! python3 -c "import flask, mariadb, gunicorn" 2>/dev/null; then
        log_error "Required Python packages are not properly installed"
        exit 1
    fi
    
    log_success "Health checks passed"
}

# ============================================================================
# SIGNAL HANDLERS FOR GRACEFUL SHUTDOWN
# ============================================================================
setup_signal_handlers() {
    trap 'log_info "Received SIGTERM, shutting down gracefully..."; exit 0' SIGTERM
    trap 'log_info "Received SIGINT, shutting down gracefully..."; exit 0' SIGINT
}

# ============================================================================
# MAIN EXECUTION
# ============================================================================
main() {
    echo "============================================================================"
    echo "🚀 Trasabilitate Application - Docker Container Startup"
    echo "============================================================================"
    echo "   Container ID: $(hostname)"
    echo "   Start Time: $(date)"
    echo "   User: $(whoami) (UID: $(id -u))"
    echo "============================================================================"
    
    # Setup signal handlers
    setup_signal_handlers
    
    # Execute initialization steps
    validate_environment
    setup_directories
    wait_for_database
    create_database_config
    initialize_database
    seed_database
    run_health_check
    
    echo "============================================================================"
    log_success "Initialization complete! Starting application..."
    echo "============================================================================"
    echo ""
    
    # Execute the main command (CMD from Dockerfile)
    exec "$@"
}

# Run main function
main "$@"