#!/usr/bin/env python3
"""Build the `ticks` config: one row per 10 Hz telemetry tick per build.

Reads upstream flat exports from the sibling recorder repo:
  builds.jsonl, telemetry/{build_id}.parquet, frames.jsonl, position_hf/{build_id}.parquet

For each build with telemetry, emits `data/ticks/{build_id:03d}.parquet`
(zero-padded so lexical sort matches numeric build_id):
  - One row per unique telemetry timestamp (the 10 Hz tick from /state/snapshot)
  - Wide-format sensor columns named "{sensor_id}.{kind}" (~64 columns)
  - Denormalized build context (build_id, job_name, ..., print_profile_name)
  - frame_chamber / frame_galvo / frame_thermal: nearest frame path in
    [tick_ts - 100ms, tick_ts], null when no frame fell in that window
  - position_hf_burst: list of {ts_offset_ms, x, y, z1, z2, r, has_homed}
    for all position_hf events in the same 100ms window

Usage:
    uv run scripts/ticks/01_extract.py            # all builds with telemetry
    uv run scripts/ticks/01_extract.py 13 26      # specific build ids
"""
import sys
from datetime import timedelta
from pathlib import Path

import polars as pl
import pyarrow as pa
import pyarrow.parquet as pq

sys.path.insert(0, str(Path(__file__).parent.parent))
from _lib import EXPORTS_DIR, DATA_DIR, iter_jsonl, load_build_to_profile_name


OUTPUT_DIR = DATA_DIR / "ticks"
WINDOW = timedelta(milliseconds=100)  # 10 Hz tick interval
FRAME_KINDS = ("chamber", "galvo", "thermal")
# frame_* path strings are relative to this directory in the upstream recorder repo.
FRAMES_DIR = EXPORTS_DIR.parent / "frames"
# HF Image feature wire format. Both fields nullable; the struct itself is null when no frame.
IMAGE_STRUCT_TYPE = pa.struct([
    pa.field("bytes", pa.binary()),
    pa.field("path",  pa.string()),
])
# Streaming chunk size in rows. Tuned so peak embedded payload per chunk stays
# under ~1 GB (thermal frames dominate at ~315 KB each).
CHUNK_ROWS = 2_000


def load_builds_index() -> dict[int, dict]:
    rows = list(iter_jsonl(EXPORTS_DIR / "builds.jsonl"))
    return {r["id"]: r for r in rows}


def load_frames_for_build(build_id: int) -> pl.DataFrame:
    """Read just the frame rows for one build out of the upstream frames.jsonl."""
    rows = [r for r in iter_jsonl(EXPORTS_DIR / "frames.jsonl")
            if r.get("build_id") == build_id]
    if not rows:
        return pl.DataFrame(schema={"ts": pl.Datetime("us", "UTC"),
                                    "kind": pl.String, "path": pl.String})
    df = pl.DataFrame(rows).select(
        pl.col("ts").str.to_datetime(time_unit="us", time_zone="UTC"),
        pl.col("kind"),
        pl.col("path"),
    )
    return df


def pivot_telemetry(tel: pl.DataFrame) -> pl.DataFrame:
    """Wide-pivot (ts, sensor_id, kind, value) → one row per ts with
    {sensor_id}.{kind} columns. Duplicate samples within a tick collapse via first."""
    tel = tel.with_columns(
        col_name=pl.col("sensor_id") + "." + pl.col("kind")
    )
    return tel.pivot(
        on="col_name", index="ts", values="value", aggregate_function="first"
    ).sort("ts")


def attach_frames(wide: pl.DataFrame, frames: pl.DataFrame) -> pl.DataFrame:
    """For each frame kind, attach the nearest path within WINDOW prior to tick_ts."""
    for kind in FRAME_KINDS:
        f = (
            frames.filter(pl.col("kind") == kind)
            .select(pl.col("ts"), pl.col("path").alias(f"frame_{kind}"))
            .sort("ts")
        )
        if f.height == 0:
            wide = wide.with_columns(pl.lit(None, dtype=pl.String).alias(f"frame_{kind}"))
            continue
        wide = wide.sort("ts").join_asof(
            f, on="ts", strategy="backward", tolerance=WINDOW
        )
    return wide


def attach_position_hf(wide: pl.DataFrame, build_id: int) -> pl.DataFrame:
    """Append a `position_hf_burst` column: list of structs of position_hf events
    in (tick_ts - WINDOW, tick_ts]. Empty list when no events in window or no parquet."""
    pos_path = EXPORTS_DIR / "position_hf" / f"{build_id}.parquet"
    burst_dtype = pl.List(
        pl.Struct({
            "ts_offset_ms": pl.Float64,
            "x":  pl.Float64, "y":  pl.Float64,
            "z1": pl.Float64, "z2": pl.Float64,
            "r":  pl.Float64, "has_homed": pl.Boolean,
        })
    )
    if not pos_path.exists():
        return wide.with_columns(pl.lit([], dtype=burst_dtype).alias("position_hf_burst"))

    pos = pl.read_parquet(pos_path).sort("ts")
    pos_records = pos.to_dicts()
    ticks = wide["ts"].to_list()

    bursts: list[list[dict]] = []
    pos_lo = 0
    for tick_ts in ticks:
        t_start = tick_ts - WINDOW
        while pos_lo < len(pos_records) and pos_records[pos_lo]["ts"] <= t_start:
            pos_lo += 1
        j = pos_lo
        burst: list[dict] = []
        while j < len(pos_records) and pos_records[j]["ts"] <= tick_ts:
            rec = pos_records[j]
            burst.append({
                "ts_offset_ms": (rec["ts"] - tick_ts).total_seconds() * 1000.0,
                "x":  rec.get("x"),  "y":  rec.get("y"),
                "z1": rec.get("z1"), "z2": rec.get("z2"),
                "r":  rec.get("r"),  "has_homed": rec.get("has_homed"),
            })
            j += 1
        bursts.append(burst)

    return wide.with_columns(pl.Series("position_hf_burst", bursts, dtype=burst_dtype))


def denormalize_build(wide: pl.DataFrame, build_row: dict,
                      profile_name_lookup: dict[int, str]) -> pl.DataFrame:
    """Prepend build-context columns to every row. Cheap in parquet thanks to
    dictionary encoding (every row in this file has the same value)."""
    bid = build_row["id"]
    return wide.with_columns(
        pl.lit(bid).alias("build_id"),
        pl.lit(build_row.get("job_name")).alias("job_name"),
        pl.lit(build_row.get("started_at")).alias("started_at"),
        pl.lit(build_row.get("ended_at")).alias("ended_at"),
        pl.lit(build_row.get("phase")).alias("phase"),
        pl.lit(profile_name_lookup.get(bid)).alias("print_profile_name"),
        pl.lit(None, dtype=pl.String).alias("inova_session_id"),
    )


def _embed_frame_column(paths: list[str | None]) -> pa.Array:
    """For one chunk's worth of paths, read the image bytes from disk and
    return a StructArray with HF Image shape. Missing path → null struct;
    missing-on-disk → null struct (warn-and-continue)."""
    raw_bytes: list[bytes | None] = []
    for p in paths:
        if p is None:
            raw_bytes.append(None)
            continue
        try:
            raw_bytes.append((FRAMES_DIR / p).read_bytes())
        except FileNotFoundError:
            raw_bytes.append(None)
    bytes_array = pa.array(raw_bytes, type=pa.binary())
    path_array  = pa.array(paths,     type=pa.string())
    # Mask the whole struct as null when there is no path. Children stay null too.
    mask = pa.array([p is None for p in paths], type=pa.bool_())
    return pa.StructArray.from_arrays(
        [bytes_array, path_array],
        fields=[pa.field("bytes", pa.binary()), pa.field("path", pa.string())],
        mask=mask,
    )


def _make_output_schema(wide_arrow_schema: pa.Schema) -> pa.Schema:
    """Replace frame_* string fields with HF Image struct fields."""
    new_fields = []
    image_field_names = {f"frame_{k}" for k in FRAME_KINDS}
    for field in wide_arrow_schema:
        if field.name in image_field_names:
            new_fields.append(pa.field(field.name, IMAGE_STRUCT_TYPE))
        else:
            new_fields.append(field)
    return pa.schema(new_fields)


def _embed_chunk(chunk: pa.Table, output_schema: pa.Schema) -> pa.Table:
    """Swap frame_* string columns for embedded image structs in this chunk."""
    arrays = []
    for field in output_schema:
        if field.name in {f"frame_{k}" for k in FRAME_KINDS}:
            paths = chunk[field.name].to_pylist()
            arrays.append(_embed_frame_column(paths))
        else:
            arrays.append(chunk[field.name].combine_chunks())
    return pa.Table.from_arrays(arrays, schema=output_schema)


def process_build(build_id: int, builds_index: dict[int, dict],
                  profile_name_lookup: dict[int, str]) -> Path | None:
    tel_path = EXPORTS_DIR / "telemetry" / f"{build_id}.parquet"
    if not tel_path.exists():
        return None

    tel = pl.read_parquet(tel_path)
    if tel.is_empty():
        return None

    wide = pivot_telemetry(tel)
    frames = load_frames_for_build(build_id)
    wide = attach_frames(wide, frames)
    wide = attach_position_hf(wide, build_id)
    wide = denormalize_build(wide, builds_index[build_id], profile_name_lookup)

    # Put build context + ts first, then sensors, then frames + burst.
    leading = ["build_id", "ts", "job_name", "started_at", "ended_at", "phase",
               "print_profile_name", "inova_session_id"]
    frame_cols = [f"frame_{k}" for k in FRAME_KINDS]
    trailing = frame_cols + ["position_hf_burst"]
    middle = [c for c in wide.columns if c not in leading and c not in trailing]
    wide = wide.select(leading + middle + trailing)

    # Stream-write: build target schema (with image structs), then iterate
    # CHUNK_ROWS-sized slices, embedding bytes per chunk to bound memory.
    base_table = wide.to_arrow()
    output_schema = _make_output_schema(base_table.schema)
    out_path = OUTPUT_DIR / f"{build_id:03d}.parquet"
    with pq.ParquetWriter(out_path, output_schema, compression="zstd") as writer:
        for i in range(0, base_table.num_rows, CHUNK_ROWS):
            chunk = base_table.slice(i, CHUNK_ROWS)
            writer.write_table(_embed_chunk(chunk, output_schema))
    return out_path


def main():
    OUTPUT_DIR.mkdir(parents=True, exist_ok=True)
    builds_index = load_builds_index()
    profile_name_lookup = load_build_to_profile_name()

    args = [int(a) for a in sys.argv[1:]]
    targets = args or sorted(int(p.stem) for p in (EXPORTS_DIR / "telemetry").glob("*.parquet"))

    for bid in targets:
        if bid not in builds_index:
            print(f"build {bid}: not in builds.jsonl, skipping")
            continue
        out = process_build(bid, builds_index, profile_name_lookup)
        if out is None:
            print(f"build {bid}: no telemetry parquet, skipping")
            continue
        rows = pl.scan_parquet(out).select(pl.len()).collect().item()
        size = out.stat().st_size
        print(f"build {bid}: wrote {rows:,} ticks → {out.relative_to(Path.cwd())}  ({size:,} bytes)")


if __name__ == "__main__":
    main()