#!/usr/bin/env python3
"""用火山引擎 v3 单向流式 TTS（/api/v3/tts/unidirectional）把双人对话脚本合成为一个 MP3。

鉴权：请求头 x-api-key + X-Api-Resource-Id（新版方式，区别于旧版 Bearer;{token}）。
用法：
    VOLC_API_KEY=<你的key> python3 synth_volc_v3.py \
        --script-file hermite_polynomials-script.json \
        --output-file output/hermite_polynomials-podcast.mp3
"""
import argparse
import base64
import json
import os
import sys
import time
import uuid

import requests

ENDPOINT = "https://openspeech.bytedance.com/api/v3/tts/unidirectional"
RESOURCE_ID = "volc.service_type.10029"

# 男女两个大模型情感音色（v2 mars bigtts）
VOICE_MALE = "zh_male_beijingxiaoye_emo_v2_mars_bigtts"
VOICE_FEMALE = "zh_female_roumeinvyou_emo_v2_mars_bigtts"

ADDITIONS = json.dumps(
    {
        "disable_markdown_filter": True,
        "enable_language_detector": True,
        "enable_latex_tn": True,
        "disable_default_bit_rate": True,
        "max_length_to_filter_parenthesis": 0,
    }
)


def synth_line(api_key: str, text: str, speaker: str, retries: int = 3) -> bytes:
    """合成一句，返回 mp3 字节。失败抛异常。"""
    headers = {
        "x-api-key": api_key,
        "X-Api-Resource-Id": RESOURCE_ID,
        "Connection": "keep-alive",
        "Content-Type": "application/json",
    }
    payload = {
        "req_params": {
            "text": text,
            "speaker": speaker,
            "additions": ADDITIONS,
            "audio_params": {"format": "mp3", "sample_rate": 24000},
        }
    }
    last_err = None
    for attempt in range(retries):
        try:
            r = requests.post(ENDPOINT, headers=headers, json=payload, timeout=60)
            if r.status_code != 200:
                last_err = f"HTTP {r.status_code}: {r.text[:200]}"
                time.sleep(1.0 + attempt)
                continue
            # 响应体可能是单个 JSON，也可能是多段（流式）。逐段解析 data 累积。
            audio = b""
            text_body = r.text.strip()
            # 尝试按行分割的多 JSON（流式 unidirectional 常见）
            chunks = []
            for line in text_body.splitlines():
                line = line.strip()
                if not line:
                    continue
                chunks.append(line)
            if not chunks:
                chunks = [text_body]
            ok = False
            for c in chunks:
                try:
                    obj = json.loads(c)
                except json.JSONDecodeError:
                    continue
                if obj.get("code") not in (0, None):
                    last_err = f"code={obj.get('code')} msg={obj.get('message')}"
                    continue
                d = obj.get("data")
                if d:
                    audio += base64.b64decode(d)
                    ok = True
            if ok and audio:
                return audio
            last_err = last_err or "no audio data in response"
            time.sleep(1.0 + attempt)
        except Exception as e:  # noqa
            last_err = str(e)
            time.sleep(1.0 + attempt)
    raise RuntimeError(f"合成失败: {last_err}")


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--script-file", required=True)
    ap.add_argument("--output-file", required=True)
    args = ap.parse_args()

    api_key = os.getenv("VOLC_API_KEY")
    if not api_key:
        print("ERROR: 需要环境变量 VOLC_API_KEY", file=sys.stderr)
        sys.exit(2)

    with open(args.script_file, encoding="utf-8") as f:
        script = json.load(f)
    lines = script["lines"]
    total = len(lines)
    print(f"加载脚本：{script.get('title','')}，共 {total} 句")

    os.makedirs(os.path.dirname(args.output_file) or ".", exist_ok=True)

    all_audio = b""
    ok_count = 0
    for i, line in enumerate(lines, 1):
        speaker = VOICE_MALE if line["speaker"] == "male" else VOICE_FEMALE
        text = line["paragraph"]
        try:
            audio = synth_line(api_key, text, speaker)
            all_audio += audio
            ok_count += 1
            print(f"[{i}/{total}] {line['speaker']:6s} ok ({len(audio)} bytes)")
        except Exception as e:  # noqa
            print(f"[{i}/{total}] {line['speaker']:6s} FAIL: {e}")
        time.sleep(0.15)  # 轻微限速

    if not all_audio:
        print("ERROR: 没有任何一句合成成功", file=sys.stderr)
        sys.exit(1)

    with open(args.output_file, "wb") as f:
        f.write(all_audio)
    print(f"\n完成：{ok_count}/{total} 句成功，已写出 {args.output_file}（{len(all_audio)} bytes）")


if __name__ == "__main__":
    main()