#!/usr/bin/env python3
import csv
from pathlib import Path
import sys
import json
import shlex
import subprocess

def get_chapters(json_path):
    """Loads the JSON file and returns all chapters."""
    with open(json_path, 'r', encoding='utf-8') as f:
        data = json.load(f)

    # The chapters are under video -> chapters
    video = data.get('video', {})
    chapters = video.get('chapters', [])

    if not chapters:
        print("No chapters found.")
        return []

    print(f"Found {len(chapters)} chapter(s) in video '{video.get('title')}':\n")

    for i, chapter in enumerate(chapters, 1):
        start_sec = chapter.get('startMilliseconds', 0) / 1000
        length_sec = chapter.get('lengthMilliseconds', 0) / 1000

        #print(f"{i}. {chapter.get('description', 'No Title')}")
        #print(f" - Type: {chapter.get('type')}")
        #print(f" - Start: {start_sec}s ({chapter.get('startMilliseconds')}ms)")
        #print(f" - Length: {length_sec}s ({chapter.get('lengthMilliseconds')}ms)")
        #print(f" - Game: {chapter.get('gameDisplayName')} (ID: {chapter.get('gameId')})")
        #print()

    return chapters

def get_video_id_from_chat(json_path: str | Path) -> str | None:
    """Gets the id inside video:{ } - from the chat json you download"""
    try:
        with open(json_path, 'r', encoding='utf-8') as f:
            data = json.load(f)
        return data.get("video", {}).get("id")
    except Exception as e:
        print(f"Could not read video.id from {json_path}: {e}")
        return None

def write_csv(data: list, file_name: str):
    # Open file with newline='' to prevent extra blank rows across platforms
    with open(file_name, "w", newline="", encoding="utf-8") as file:
        writer = csv.writer(file)
        
        # Write all rows at once
        writer.writerows(data)

def run_command(cmd_str: str, progress_prefix: str = "Progress", look_for: list = ["frame=", "time=", "fps=", "Rendering frame"]) -> bool:
   """Runs a system command, streams its output live, and reports errors on failure."""
   args = shlex.split(cmd_str)

   # Redirect stderr to stdout to catch all logging/progress in one stream
   process = subprocess.Popen(
        args,
        stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT,
        text=True,
        bufsize=1
    )
   print(f"Executing: {cmd_str[:90]}...")

   # Maintain a small buffer history to display context if a crash occurs
   output_history = []

   # Stream the output live to the terminal
   while True:
        line = process.stdout.readline()
        if not line and process.poll() is not None:
            break
        if line:
            clean_line = line.strip()
            output_history.append(clean_line) # Keep history for error reporting
            
            # Keep history slim by only keeping the last 20 lines
            if len(output_history) > 20:
                output_history.pop(0)

            # Only print updates that show progress metrics to keep terminal clean
            if any(metric in clean_line for metric in look_for):
                sys.stdout.write(f"\r[{progress_prefix}] {clean_line}")
                sys.stdout.flush()
            elif "Error" in clean_line or "failed" in clean_line:
                print(f"\n[Alert] {clean_line}")
            
   print("\n") # New line after process finishes
   
   # Evaluate success status
   success = (process.returncode == 0)
   
   if not success:
       print(f"❌ Command failed with exit code: {process.returncode}")
       print("--- Technical Error Details (Last 5 lines of output) ---")
       # Print the last 5 captured lines to show the exact point of failure
       for error_line in output_history[-5:]:
           print(f"  > {error_line}")
       print("---------------------------------------------------------")

   return success