import os
import subprocess
import re
import copy
import time

template_video_part = {
    "filename": "",
    "file_ext": "flv",
    "start": "",
    "end": "",
    "part_start": "",
    "duration": "",
}
template_current_video = {
    "parts": [],
    "pack_ext": "mp4",
    "out_ext": "mp4",
    "suffix": "",
    "target_name": "",
}


def merge_video_parts_and_split(video):
    if len(video["parts"]) <= 1:
        raise Exception("视频片段不够")
    prev_part = video["parts"].pop(0)
    if prev_part["part_start"] is None:
        raise Exception("视频片段part_start读取异常")
    ts_part = []
    for part in video["parts"]:
        if part["part_start"] is None:
            raise Exception("视频片段part_start读取异常")
        if prev_part["duration"] == "":
            duration = float(part["part_start"]) - float(prev_part["part_start"])
            if duration <= 60:
                raise Exception("视频片段duration过小")
            prev_part["duration"] = str(duration)
        new_filename = str(time.time())
        os.system(" ".join([
            "ffmpeg", "-y", "-i", "{filename}.{file_ext}".format_map(prev_part),
            "-c copy", "-f mpegts", "-t {duration}".format_map(prev_part),
            "{}.ts".format(new_filename)
        ]))
        os.system(" ".join([
            "ffmpeg", "-y", "-i", "{}.ts".format(new_filename),
            "-c copy", "-f mpegts", "-ss {start}".format_map(prev_part) if prev_part["start"] != "" else "",
            "-to {end}".format_map(prev_part) if prev_part["end"] != "" else "",
            "{filename}.ts".format_map(prev_part)
        ]))
        os.remove("{}.ts".format(new_filename))
        ts_part.append("{filename}.ts".format_map(prev_part))
        prev_part = part
    os.system(" ".join([
        "ffmpeg", "-y", "-i", "{filename}.{file_ext}".format_map(prev_part),
        "-c copy", "-f mpegts", "-ss {start}".format_map(prev_part) if prev_part["start"] != "" else "",
        "-to {end}".format_map(prev_part) if prev_part["end"] != "" else "",
        "{filename}.ts".format_map(prev_part)
    ]))
    ts_part.append("{filename}.ts".format_map(prev_part))
    os.system(" ".join([
        "ffmpeg", "-y", "-i", "\"concat:{}\"".format("|".join(ts_part)),
        "-c copy", "-f {pack_ext}".format_map(video),
        "{target_name}{suffix}.{out_ext}".format_map(video),
    ]))
    for _delete in ts_part:
        os.remove(_delete)


def get_video_part_start(file):
    s = subprocess.Popen([
        "ffprobe", file
    ], bufsize=0, stderr=subprocess.PIPE, universal_newlines=True)
    while True:
        line = s.stderr.readline()
        if line == "" and not s.poll():
            break
        line = line.strip()
        match = re.search(r", start: (\d+\.\d+)", line)
        if match:
            return match.group(1)


with open("../a.txt", "r", encoding="gbk") as f:
    skip_current = False
    current_video = copy.deepcopy(template_current_video)
    for current_line in f.readlines():
        current_line = current_line.strip()
        if current_line == "":
            if skip_current:
                skip_current = False
            else:
                merge_video_parts_and_split(current_video)
                current_video = copy.deepcopy(template_current_video)
            continue
        if current_line.startswith("=" * 5):
            break
        if "-" in current_line:
            skip_current = True
            continue
        if "~" in current_line:
            file_params = current_line.split("~")
            for file_param in file_params:
                video_part = copy.deepcopy(template_video_part)
                bias_time = ""
                if "+" in file_param:
                    filename, bias_time = file_param.split("+", 1)
                else:
                    filename = file_param
                if "." in filename:
                    filename, file_ext = filename.split(".", 1)
                    video_part['file_ext'] = file_ext
                video_part["filename"] = filename
                if current_video["suffix"] == "":
                    suffix, _ = filename.split("_")
                    current_video['suffix'] = "_" + suffix[4:]
                if len(current_video["parts"]) == 0:
                    video_part['start'] = bias_time
                else:
                    video_part['end'] = bias_time
                video_part['part_start'] = get_video_part_start("{filename}.{file_ext}".format_map(video_part))
                current_video["parts"].append(video_part)
            continue
        else:
            if len(current_video["parts"]) == 0:
                skip_current = True
                continue
            current_video['target_name'] = current_line
            continue