"""Read the data section of a Z-wafer CSV into DataRecords, or the official headerless CSV."""
from __future__ import annotations
from pathlib import Path

from pygui.backend.wafer.zwafer_models import DataRecord, Sensor

def read_data_records(file_path: str) -> list[DataRecord]:
    records: list[DataRecord] = []
    in_data = False
    with Path(file_path).open("r", encoding="utf-8") as file_handle:
        for line in file_handle:
            line = line.rstrip().rstrip(",").strip()
            if not line:
                continue
            if not in_data:
                if line.split(",")[0].lower() == "data":
                    in_data = True
                continue
            cols = [c.strip() for c in line.split(",") if c.strip() != ""]
            try:
                nums = [float(c) for c in cols]
            except ValueError:
                continue
            if not nums:
                continue
            records.append(DataRecord(time=nums[0], values=nums[1:]))
        return records


def is_official_csv(file_path: str) -> bool:
    """Return True if the file uses the headerless official format (sensor-name header row, no 'data' sentinel)."""
    with Path(file_path).open("r", encoding="utf-8") as f:
        first = f.readline().rstrip().rstrip(",")
    if not first:
        return False
    parts = [p.strip() for p in first.split(",") if p.strip()]
    # Official format: first cell looks like "SensorN" (starts with letter, not key=value)
    return bool(parts) and parts[0].lower().startswith("sensor") and "=" not in parts[0]


def read_official_csv(file_path: str) -> tuple[list[Sensor], list[DataRecord]]:
    """Parse the headerless official CSV: row 0 = sensor names, rows 1+ = values (no timestamp)."""
    from pygui.backend.wafer.wafer_layouts import load_layout_for_wafer_id

    stem = Path(file_path).stem
    wafer_id = stem.split("-")[0] if "-" in stem else stem
    try:
        sensors = load_layout_for_wafer_id(wafer_id)
    except KeyError:
        return [], []

    records: list[DataRecord] = []
    with Path(file_path).open("r", encoding="utf-8") as f:
        f.readline()  # skip sensor-name header
        for i, line in enumerate(f):
            line = line.rstrip().rstrip(",")
            if not line:
                continue
            cols = [c.strip() for c in line.split(",") if c.strip()]
            try:
                values = [float(c) for c in cols]
            except ValueError:
                continue
            if values:
                records.append(DataRecord(time=float(i) * 0.5, values=values))
    return sensors, records