import os
import zlib
import glob
import time
import sys
from core.connection import BuzzerError

def get_file_crc32(filepath: str) -> int:
    """Berechnet die IEEE CRC32-Prüfsumme einer Datei in Chunks."""
    crc = 0
    with open(filepath, 'rb') as f:
        while chunk := f.read(4096):
            crc = zlib.crc32(chunk, crc)
    return crc & 0xFFFFFFFF

def execute(conn, sources: list, target: str):
    # 1. Globbing auflösen
    resolved_files = [f for src in sources for f in glob.glob(src) if os.path.isfile(f)]
    
    if not resolved_files:
        print("Keine gültigen Dateien gefunden.")
        return

    total_size_all = sum(os.path.getsize(f) for f in resolved_files)
    sent_all = 0
    start_time_all = time.monotonic()
    is_target_dir = target.endswith('/')

    for filepath in resolved_files:
        filename = os.path.basename(filepath)
        filesize = os.path.getsize(filepath)
        crc32 = get_file_crc32(filepath)
        dest_path = f"{target}{filename}" if is_target_dir else target
        
        print(f"Sende 📄 {filename} ({filesize/1024:.1f} KB) -> {dest_path}")
        
        start_time_file = time.monotonic()
        sent_file = 0

        def progress_handler(chunk_len):
            nonlocal sent_file, sent_all
            sent_file += chunk_len
            sent_all += chunk_len
            
            elapsed = time.monotonic() - start_time_file
            speed = (sent_file / 1024) / elapsed if elapsed > 0 else 0
            
            # Prozentberechnungen
            perc_file = (sent_file / filesize) * 100
            perc_all = (sent_all / total_size_all) * 100
            
            # ETA (Basierend auf Gesamtgeschwindigkeit)
            elapsed_all = time.monotonic() - start_time_all
            avg_speed_all = sent_all / elapsed_all if elapsed_all > 0 else 0
            eta_sec = (total_size_all - sent_all) / avg_speed_all if avg_speed_all > 0 else 0
            eta_str = f"{int(eta_sec // 60):02d}:{int(eta_sec % 60):02d}"

            # Ausgabezeile (\r überschreibt die aktuelle Zeile)
            sys.stdout.write(
                f"\r  \033[90mProg: {perc_file:3.0f}% | Gesamt: {perc_all:3.0f}% | "
                f"{speed:6.1f} KB/s | ETA: {eta_str}\033[0m"
            )
            sys.stdout.flush()

        try:
            cmd = f"put {dest_path};{filesize};{crc32}\n"
            conn.serial.write(cmd.encode('utf-8'))
            conn.serial.flush()
            
            # Binärtransfer mit unserem Handler
            conn.send_binary(filepath, progress_callback=progress_handler)
            
            # Zeile nach Erfolg abschließen
            print(f"\r  \033[32mFertig: {filename} übertragen.              \033[0m")
        except Exception as e:
            print(f"\n  ❌ \033[31mFehler: {e}\033[0m")

    total_duration = time.monotonic() - start_time_all
    print(f"\nAlle {len(resolved_files)} Dateien in {total_duration:.1f}s übertragen.")