import ffmpeg
import subprocess
import json
import os
from collections import Counter

def is_av1(filepath):
    """Check if a video file is already AV1-encoded."""
    try:
        probe = ffmpeg.probe(filepath)
        for stream in probe['streams']:
            if stream['codec_type'] == 'video' and 'codec_name' in stream:
                if stream['codec_name'] == 'av1':
                    return True
    except ffmpeg.Error as e:
        print(f"Error probing {filepath}: {e}")
    return False


def get_fps(filepath):
    """Get the frames per second (FPS) of the input video using ffmpeg.probe."""
    try:
        probe = ffmpeg.probe(filepath)
        video_stream = next((s for s in probe['streams'] if s['codec_type'] == 'video'), None)
        if video_stream and 'r_frame_rate' in video_stream:
            fps_str = video_stream['r_frame_rate']  # e.g. "30/1", "25/1"
            num, den = map(int, fps_str.split('/'))
            return num / den
    except ffmpeg.Error as e:
        print(f"Error getting FPS for {filepath}: {e}")
    return None

def get_video_info(filepath):
    """
    Returns dict:
      { 'width': int, 'height': int, 'bitrate': int, 'fps': float }
    - bitrate is Kbps (rounded down)
    - uses stream bit_rate, else format bit_rate, else computed
    """
    cmd = [
        "ffprobe","-v","error",
        "-select_streams","v:0",
        "-show_entries","stream=width,height,bit_rate,r_frame_rate",
        "-show_entries","format=bit_rate,duration",
        "-of","json", filepath
    ]
    r = subprocess.run(cmd, capture_output=True, text=True)
    if r.returncode:
        return {"width": 0, "height": 0, "bitrate": 0, "fps": 0.0}

    try:
        d = json.loads(r.stdout or "{}")
        s = (d.get("streams") or [{}])[0]
        f = d.get("format") or {}

        width  = int(s.get("width") or 0)
        height = int(s.get("height") or 0)

        # fps (r_frame_rate like "30000/1001")
        fps = 0.0
        rfr = s.get("r_frame_rate")
        if rfr and rfr != "0/0":
            try:
                num, den = rfr.split("/")
                num = float(num); den = float(den)
                fps = (num/den) if den else 0.0
            except Exception:
                pass

        # bitrate in bps → prefer stream, fallback to format, else compute
        br_bps = s.get("bit_rate") or f.get("bit_rate")
        if not br_bps:
            try:
                dur = float(f.get("duration") or 0)
                if dur > 0:
                    br_bps = int(os.path.getsize(filepath) * 8 / dur)
            except Exception:
                br_bps = 0
        br_kbps = int(int(br_bps or 0) / 1000)

        return {"width": width, "height": height, "bitrate": br_kbps, "fps": fps}
    except Exception:
        return {"width": 0, "height": 0, "bitrate": 0, "fps": 0.0}
    
def get_common_resolution(group):
    """Most common (w,h) across the group's videos. Fallback 1280x720."""
    resolutions = []
    for v in group:
        info = get_video_info(v["filepath"])
        w, h = info.get("width"), info.get("height")
        if w and h:
            resolutions.append((w, h))
    if not resolutions:
        return (1280, 720)
    return Counter(resolutions).most_common(1)[0][0]

def get_target_resolution(group):
    """
    Choose (w,h) whose videos have the highest *total duration*.
    Tie-breakers: higher count, then larger area. Fallback 1280x720.
    """
    totals = {}  # (w,h) -> total duration
    counts = {}  # (w,h) -> number of files

    for v in group:
        info = get_video_info(v["filepath"])
        w, h = info.get("width"), info.get("height")
        if not (w and h):
            continue

        # Prefer DB duration if present, else probe info['duration'], else 0
        dur = v.get("duration", info.get("duration", 0))
        try:
            dur = float(dur)
        except (TypeError, ValueError):
            dur = 0.0

        key = (w, h)
        totals[key] = totals.get(key, 0.0) + dur
        counts[key] = counts.get(key, 0) + 1

    if not totals:
        return (1280, 720)

    def sort_key(item):
        (w, h), total = item
        cnt = counts[(w, h)]
        area = (w or 0) * (h or 0)
        return (total, cnt, area)

    best_resolution = max(totals.items(), key=sort_key)[0]
    return best_resolution


def get_target_bitrate(width, height):
    """Your existing function to choose a bitrate based on resolution."""
    resolutions = {(854, 480): 1000,(1280, 720): 1500,(1920, 1080): 3000,(2560, 1440): 5000,(3840, 2160): 12000}
    for res, bitrate in resolutions.items():
        if width <= res[0] and height <= res[1]:
            return bitrate
    return 2500