"""Per-turn WAV recorder for voice brains.

Direct port of Project/Sanad/voice/sanad_voice.py::TurnRecorder. Saves each
conversation turn as two WAV files:

    <timestamp>_user.wav   mono int16 @ 16 kHz (what the mic captured)
    <timestamp>_robot.wav  mono int16 @ 24 kHz (what the brain spoke)

Plus an index.json that appends one entry per turn with the transcripts.

A turn starts when audio first flows through `capture_user` or
`capture_robot`, and ends on `finish_turn`. Call pattern matches Sanad
exactly: `capture_user`, `capture_robot`, `add_user_text`, `add_robot_text`,
`finish_turn`.

Disable via config: stt.gemini_record_enabled = false (the caller passes
`enabled=False`).
"""

from __future__ import annotations

import json
import logging
import os
import threading
import time
import wave
from datetime import datetime

log = logging.getLogger("turn_recorder")


class TurnRecorder:
    """Saves each turn as two WAV files: user mic + model output."""

    def __init__(
        self,
        enabled: bool = True,
        out_dir: str = "",
        user_rate: int = 16000,
        robot_rate: int = 24000,
        keep_count: int = 50,
    ):
        self.enabled = bool(enabled) and bool(out_dir)
        self.out_dir = out_dir
        self.user_rate = int(user_rate)
        self.robot_rate = int(robot_rate)
        # Cap the number of turn-pairs on disk. 0/negative = unlimited.
        # finish_turn() prunes the oldest WAVs after every save so the
        # folder can never balloon past keep_count*2 files in the wild.
        self.keep_count = int(keep_count)
        if self.enabled:
            os.makedirs(self.out_dir, exist_ok=True)
        self._lock = threading.Lock()
        self._user_buf = []
        self._robot_buf = []
        self._user_text = ""
        self._robot_text = ""
        self._started_at = 0.0

    def capture_user(self, pcm: bytes) -> None:
        if not self.enabled or not pcm:
            return
        with self._lock:
            if not self._user_buf and not self._robot_buf:
                self._started_at = time.time()
            self._user_buf.append(pcm)

    def capture_robot(self, pcm: bytes) -> None:
        if not self.enabled or not pcm:
            return
        with self._lock:
            if not self._user_buf and not self._robot_buf:
                self._started_at = time.time()
            self._robot_buf.append(pcm)

    def add_user_text(self, text: str) -> None:
        if text and self.enabled:
            with self._lock:
                self._user_text = (self._user_text + " " + text).strip()

    def add_robot_text(self, text: str) -> None:
        if text and self.enabled:
            with self._lock:
                self._robot_text = (self._robot_text + " " + text).strip()

    def finish_turn(self) -> dict:
        if not self.enabled:
            return {}
        with self._lock:
            user_data = b"".join(self._user_buf)
            robot_data = b"".join(self._robot_buf)
            user_text = self._user_text
            robot_text = self._robot_text
            started_at = self._started_at
            self._user_buf.clear()
            self._robot_buf.clear()
            self._user_text = ""
            self._robot_text = ""

        if not user_data and not robot_data:
            return {}

        stamp = datetime.fromtimestamp(started_at).strftime("%Y%m%d_%H%M%S")
        entry = {
            "timestamp": stamp,
            "started_at": started_at,
            "user_text": user_text,
            "robot_text": robot_text,
        }
        try:
            if user_data:
                p = os.path.join(self.out_dir, "{}_user.wav".format(stamp))
                self._save_wav(p, user_data, self.user_rate)
                entry["user_wav"] = p
                entry["user_duration_sec"] = round(
                    len(user_data) / (self.user_rate * 2), 3,
                )
            if robot_data:
                p = os.path.join(self.out_dir, "{}_robot.wav".format(stamp))
                self._save_wav(p, robot_data, self.robot_rate)
                entry["robot_wav"] = p
                entry["robot_duration_sec"] = round(
                    len(robot_data) / (self.robot_rate * 2), 3,
                )
            self._append_index(entry)
            self._rotate()
            log.info(
                "recorded turn → %s (user %.1fs, robot %.1fs)",
                stamp,
                entry.get("user_duration_sec", 0),
                entry.get("robot_duration_sec", 0),
            )
        except Exception as exc:
            log.warning("recording save failed: %s", exc)
        return entry

    def _rotate(self) -> None:
        """Prune oldest WAV files when count exceeds keep_count*2 (one
        user + one robot per turn). index.json is never touched."""
        if self.keep_count <= 0:
            return
        try:
            wavs = [
                f for f in os.listdir(self.out_dir)
                if f.endswith(".wav")
            ]
            if len(wavs) <= self.keep_count * 2:
                return
            # Sort oldest-first by mtime; remove the head of the list.
            wavs_paths = [os.path.join(self.out_dir, f) for f in wavs]
            wavs_paths.sort(key=lambda p: os.path.getmtime(p))
            to_remove = wavs_paths[: len(wavs_paths) - self.keep_count * 2]
            for p in to_remove:
                try:
                    os.remove(p)
                except Exception:
                    pass
        except Exception as exc:
            log.warning("recording rotate failed: %s", exc)

    @staticmethod
    def _save_wav(path: str, pcm: bytes, rate: int) -> None:
        with wave.open(path, "wb") as wf:
            wf.setnchannels(1)
            wf.setsampwidth(2)
            wf.setframerate(rate)
            wf.writeframes(pcm)

    def _append_index(self, entry: dict) -> None:
        idx_path = os.path.join(self.out_dir, "index.json")
        try:
            if os.path.exists(idx_path):
                with open(idx_path, "r", encoding="utf-8") as f:
                    payload = json.load(f)
                if not isinstance(payload, dict):
                    payload = {"records": []}
            else:
                payload = {"records": []}
        except Exception:
            payload = {"records": []}
        payload.setdefault("records", []).append(entry)
        payload["total_records"] = len(payload["records"])
        try:
            with open(idx_path, "w", encoding="utf-8") as f:
                json.dump(payload, f, indent=2, ensure_ascii=False)
        except Exception as exc:
            log.warning("index.json write failed: %s", exc)