#!/usr/bin/env python3
"""
upload_track.py — serial audio uploader for baby_mobile_v2 POC_INTERNAL_FLASH mode

Usage:
    python upload_track.py <port> <track_num> <file>

Supported formats: .raw, .wav, .mp3, .ogg, .flac, .aac, .m4a (anything ffmpeg handles)

Requires: pyserial  (pip install pyserial)
          ffmpeg in PATH for non-WAV/RAW files
"""

import sys
import os
import shutil
import struct
import subprocess
import serial
import time

CHUNK_SIZE = 512
BAUD_RATE  = 115200
TIMEOUT_S  = 10.0

RAW_EXTS = {'.raw'}
WAV_EXTS = {'.wav'}


def convert_to_pcm(path: str) -> bytes:
    ext = os.path.splitext(path)[1].lower()

    if ext in RAW_EXTS:
        with open(path, "rb") as f:
            return f.read()

    if ext in WAV_EXTS:
        with open(path, "rb") as f:
            data = f.read()
        if data[:4] == b"RIFF":
            try:
                audio_format  = struct.unpack_from("<H", data, 20)[0]
                num_channels  = struct.unpack_from("<H", data, 22)[0]
                sample_rate   = struct.unpack_from("<I", data, 24)[0]
                bits_per_samp = struct.unpack_from("<H", data, 34)[0]
                needs_convert = (audio_format != 1 or num_channels != 1
                                 or sample_rate != 16000 or bits_per_samp != 8)
            except Exception:
                needs_convert = True

            if not needs_convert:
                print("WAV is already 8-bit mono 16kHz — stripping header")
                return data[44:]
            print("WAV needs resampling — converting via ffmpeg")
        # fall through to ffmpeg conversion

    # Use ffmpeg for everything else (mp3, ogg, flac, aac, non-conformant wav...)
    if not shutil.which('ffmpeg'):
        sys.exit(
            "ERROR: ffmpeg not found. Install it or convert manually:\n"
            f"  ffmpeg -i \"{path}\" -ar 8000 -ac 1 -f u8 -acodec pcm_u8 out.raw"
        )

    print(f"Converting {os.path.basename(path)} via ffmpeg...")
    result = subprocess.run(
        ['ffmpeg', '-y', '-i', path,
         '-ar', '16000', '-ac', '1', '-f', 'u8', '-acodec', 'pcm_u8', 'pipe:1'],
        capture_output=True
    )
    if result.returncode != 0:
        sys.exit(f"ERROR: ffmpeg failed:\n{result.stderr.decode(errors='replace')[-400:]}")

    pcm = result.stdout
    duration = len(pcm) / 16000
    print(f"  Converted: {len(pcm):,} bytes ({duration:.1f}s)")
    return pcm


def upload(port: str, track_num: int, pcm: bytes) -> None:
    total = len(pcm)
    print(f"Uploading {total} bytes as track {track_num} via {port} ...")

    # dsrdtr=False / rtscts=False prevents Windows from toggling DTR/RTS on
    # port open, which would reset the nRF52840 and stall the 5-second boot loop.
    with serial.Serial(port, BAUD_RATE, timeout=2.0,
                       dsrdtr=False, rtscts=False) as ser:
        # Drain any boot output; send a bare newline first to flush any
        # partial line sitting in the firmware's line buffer.
        time.sleep(0.5)
        ser.reset_input_buffer()
        ser.write(b"\n")
        ser.flush()
        time.sleep(0.1)
        ser.reset_input_buffer()

        # Send UPLOAD command
        cmd = f"UPLOAD {track_num} {total}\n"
        ser.write(cmd.encode())
        ser.flush()

        # Wait for READY — print everything received so failures are diagnosable
        deadline = time.time() + TIMEOUT_S
        while True:
            if time.time() > deadline:
                sys.exit("Timed out waiting for READY")
            line = ser.readline().decode(errors="replace").strip()
            if line == "READY":
                break
            if line:
                print(f"  firmware: {line}")

        # Stream PCM in chunks; stop early if firmware sends ERR
        sent = 0
        err_line = None
        ser.timeout = 0.05  # short timeout so we can poll for ERR while sending
        while sent < total:
            chunk = pcm[sent:sent + CHUNK_SIZE]
            ser.write(chunk)
            sent += len(chunk)
            pct = sent * 100 // total
            print(f"\r  {sent}/{total} bytes ({pct}%)   ", end="", flush=True)
            # Check for early ERR from firmware (e.g. LittleFS full)
            line = ser.readline().decode(errors="replace").strip()
            if line.startswith("ERR"):
                err_line = line
                break
        print()
        ser.timeout = 2.0

        if err_line:
            print(f"ERROR from firmware: {err_line}")
            # at= tells us how many bytes were accepted before the failure
            if "at=" in err_line:
                accepted = int(err_line.split("at=")[1].split()[0])
                safe = int(accepted * 0.9)  # 10% headroom
                max_s = safe / 16000
                print(f"  LittleFS accepted {accepted} bytes before full.")
                print(f"  Safe clip length: ~{max_s:.1f}s")
                print(f"  Trim with:  ffmpeg -i input.mp3 -t {max_s:.0f} -ar 16000 -ac 1 -f u8 out.raw")
            sys.exit(1)

        # Wait for OK
        deadline = time.time() + TIMEOUT_S
        while True:
            if time.time() > deadline:
                sys.exit("Timed out waiting for OK")
            line = ser.readline().decode(errors="replace").strip()
            if line.startswith("OK"):
                print(f"Upload done: {line}")
                break
            if line.startswith("ERR"):
                print(f"ERROR from firmware: {line}")
                sys.exit(1)
            if line:
                print(f"  firmware: {line}")

        # Verify: request hex dump of first 256 bytes and compare
        print("Verifying...")
        ser.reset_input_buffer()
        ser.write(f"DUMP {track_num}\n".encode())
        ser.flush()

        deadline = time.time() + TIMEOUT_S
        fw_size = None
        fw_bytes = bytearray()
        while True:
            if time.time() > deadline:
                print("WARNING: timed out waiting for DUMP response")
                break
            line = ser.readline().decode(errors="replace").strip()
            if not line:
                continue
            if line.startswith("SIZE"):
                fw_size = int(line.split()[1])
            elif line == "END":
                break
            elif line == "NO FILE":
                print("ERROR: firmware says file does not exist!")
                break
            else:
                # Parse hex bytes
                for tok in line.split():
                    try:
                        fw_bytes.append(int(tok, 16))
                    except ValueError:
                        pass

        if fw_size is not None:
            print(f"  Firmware file size: {fw_size} bytes")
            if fw_size == 0:
                print("  ERROR: file is empty — write failed (LittleFS full?)")
            elif fw_size < total:
                print(f"  WARNING: only {fw_size}/{total} bytes written (LittleFS full?)")
            else:
                print(f"  Size OK: {fw_size}/{total}")

        compare_len = min(len(fw_bytes), len(pcm), 256)
        if compare_len > 0:
            mismatches = sum(1 for i in range(compare_len) if fw_bytes[i] != pcm[i])
            if mismatches == 0:
                print(f"  Data OK: first {compare_len} bytes match")
            else:
                print(f"  ERROR: {mismatches}/{compare_len} byte mismatches in first {compare_len} bytes")
                print(f"  Expected: {' '.join(f'{b:02X}' for b in pcm[:16])}")
                print(f"  Got:      {' '.join(f'{b:02X}' for b in fw_bytes[:16])}")


def main():
    if len(sys.argv) != 4:
        print(__doc__)
        sys.exit(1)

    port      = sys.argv[1]
    track_num = int(sys.argv[2])
    path      = sys.argv[3]

    if not 0 <= track_num < 32:
        sys.exit("track_num must be 0–31")

    pcm = convert_to_pcm(path)
    if not pcm:
        sys.exit("File is empty after conversion")

    upload(port, track_num, pcm)


if __name__ == "__main__":
    main()