#!/usr/bin/env python3
"""Check BOM output for common issues.

Usage:
    python bom_check.py path/to/bom.csv

Checks:
    - All components have footprint assigned
    - All components have value assigned (resistors, capacitors, inductors)
    - No duplicate reference designators
    - Passive values are standard E-series (basic check)
    - Flags DNP components
"""

from __future__ import annotations

import csv
import re
import sys
from pathlib import Path

# Standard E12 values (covers most common passives)
E12_VALUES = {1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2}

PASSIVE_PREFIXES = {"R", "C", "L"}


def normalize_value(value_str: str) -> float | None:
    """Try to extract numeric value from component value string."""
    match = re.match(r"^(\d+\.?\d*)\s*([kKmMuUnNpP]?)", value_str.strip())
    if not match:
        return None

    num = float(match.group(1))
    suffix = match.group(2).lower()

    multipliers = {"k": 1e3, "m": 1e6, "u": 1e-6, "n": 1e-9, "p": 1e-12}
    return num * multipliers.get(suffix, 1.0)


def is_e12_compatible(value: float) -> bool:
    """Check if a value falls on an E12 series value (within 5% tolerance)."""
    if value <= 0:
        return False

    # Normalize to 1.0-9.99 range
    normalized = value
    while normalized >= 10:
        normalized /= 10
    while normalized < 1:
        normalized *= 10

    for e12 in E12_VALUES:
        if abs(normalized - e12) / e12 < 0.05:
            return True
    return False


def check_bom(filepath: Path) -> tuple[list[str], list[str]]:
    errors: list[str] = []
    warnings: list[str] = []
    refs_seen: set[str] = set()

    with filepath.open(newline="", encoding="utf-8") as f:
        reader = csv.DictReader(f)

        if reader.fieldnames is None:
            errors.append("BOM file has no headers")
            return errors, warnings

        # Try common column name patterns
        ref_col = next((c for c in reader.fieldnames if c.lower() in ("ref", "reference", "designator")), None)
        val_col = next((c for c in reader.fieldnames if c.lower() in ("value", "val")), None)
        fp_col = next((c for c in reader.fieldnames if c.lower() in ("footprint", "package", "fp")), None)

        if ref_col is None:
            errors.append("Cannot find reference designator column in BOM")
            return errors, warnings

        for row_num, row in enumerate(reader, start=2):
            ref = row.get(ref_col, "").strip()
            if not ref:
                continue

            # Duplicate check
            if ref in refs_seen:
                errors.append(f"Row {row_num}: duplicate reference '{ref}'")
            refs_seen.add(ref)

            # Footprint check
            footprint = row.get(fp_col, "").strip() if fp_col else ""
            if not footprint:
                errors.append(f"{ref}: missing footprint")

            # Value check for passives
            value = row.get(val_col, "").strip() if val_col else ""
            prefix = re.match(r"^[A-Z]+", ref)
            if prefix and prefix.group() in PASSIVE_PREFIXES:
                if not value or value.upper() == "DNP":
                    if value.upper() == "DNP":
                        warnings.append(f"{ref}: marked as DNP — verify this is intentional")
                    else:
                        errors.append(f"{ref}: passive component missing value")
                else:
                    numeric = normalize_value(value)
                    if numeric and not is_e12_compatible(numeric):
                        warnings.append(f"{ref}: value '{value}' may not be standard E12 series")

    return errors, warnings


def main() -> int:
    if len(sys.argv) < 2:
        print(f"Usage: {sys.argv[0]} <path/to/bom.csv>")
        return 1

    path = Path(sys.argv[1])
    if not path.exists():
        print(f"File not found: {path}")
        return 1

    errors, warnings = check_bom(path)

    for w in warnings:
        print(f"  WARN: {w}")
    for e in errors:
        print(f"  ERROR: {e}")

    print(f"\n  {len(errors)} errors, {len(warnings)} warnings")
    return 1 if errors else 0


if __name__ == "__main__":
    sys.exit(main())