"""Gemini REST client for dubbing-script translation (no SDK needed)."""
import json
import re
import time
import urllib.request

MODEL = "gemini-3.5-flash-lite"
MAX_RETRIES = 4
CHUNK = 25


PROMPT_EN2MM = """You are a professional dubbing script translator for short videos.
Translate each spoken line into natural SPOKEN Burmese (စကားပြောဘာသာ) — the way real people talk, never stiff written Burmese (စာရေးဘာသာ).

Rules:
- Translate meaning, tone and emotion — NEVER word-for-word. A natural Burmese line that captures the feeling beats a literal one.
- Keep it concise: each line will be SPOKEN in about the same time as the original, so avoid long-winded phrasing.
- TIMING IS CRITICAL: Burmese speech runs longer than English, so compress hard — use the shortest natural phrasing, drop filler words and repetition, keep only the core meaning and tone. A slightly shorter line is always better than a longer one.
- Match the speaker: casual stays casual, jokes stay funny in Burmese, adapt idioms to Burmese equivalents.
- Names and places stay as-is (transliterated if needed).
- Output format: exactly one line per input as "N|||translation" (N = the number I give you). Nothing else — no explanations."""


PROMPT_MM2EN = """You are a professional dubbing script translator for short videos.
Translate each spoken Burmese line into natural SPOKEN English — the way real people talk in videos, never stiff or literal.

Rules:
- Translate meaning, tone and emotion — NEVER word-for-word. A natural English line that captures the feeling beats a literal one.
- Keep it concise: each line will be SPOKEN in about the same time as the original, so avoid long-winded phrasing.
- TIMING IS CRITICAL: compress hard — use the shortest natural phrasing, drop filler words and repetition, keep only the core meaning and tone. A slightly shorter line is always better than a longer one.
- Match the speaker: casual stays casual, jokes stay funny in English, adapt Burmese idioms to English equivalents.
- Names and places stay as-is.
- Output format: exactly one line per input as "N|||translation" (N = the number I give you). Nothing else — no explanations."""


def _call(prompt, api_key):
    url = (f"https://generativelanguage.googleapis.com/v1beta/models/{MODEL}"
           f":generateContent?key={api_key}")
    body = {"contents": [{"parts": [{"text": prompt}]}],
            "generationConfig": {"maxOutputTokens": 8192, "temperature": 0.7}}
    for attempt in range(MAX_RETRIES):
        try:
            req = urllib.request.Request(url, data=json.dumps(body).encode(),
                                         headers={"Content-Type": "application/json"})
            with urllib.request.urlopen(req, timeout=180) as r:
                data = json.loads(r.read().decode())
            parts = data["candidates"][0].get("content", {}).get("parts", [])
            text = "".join(p.get("text", "") for p in parts)
            if text.strip():
                return text
            raise RuntimeError("empty response")
        except Exception:
            if attempt == MAX_RETRIES - 1:
                raise
            time.sleep(2 ** attempt * 2)
    raise RuntimeError("gemini unreachable")


def translate_lines(lines, direction, api_key):
    """lines: [str] -> [translated str], same order."""
    prompt = PROMPT_EN2MM if direction == "en2mm" else PROMPT_MM2EN
    out = []
    for start in range(0, len(lines), CHUNK):
        chunk = lines[start:start + CHUNK]
        numbered = "\n".join(f"{i + 1}|||{t}" for i, t in enumerate(chunk))
        raw = _call(prompt + "\n\nTranslate these lines:\n" + numbered, api_key)
        results = {}
        for line in raw.strip().split("\n"):
            m = re.match(r"(\d+)\|\|\|(.+)", line.strip())
            if m:
                results[int(m.group(1))] = m.group(2).strip()
        for i, orig in enumerate(chunk, 1):
            out.append(results.get(i, orig))
    return out