"""Parser for STM32CubeMX .ioc files (key=value format)."""

import re

# Matches GPIO pin names like PA0, PB12, PC3, PD2, PF0-OSC_IN, PB8-BOOT0
# Also handles CubeMX aliases like "PC14-OSC32_IN\ (PC14)" or "PA11\ [PA9]"
_GPIO_RE = re.compile(r"^(P[A-K]\d+(?:-[A-Z_0-9]+)?)(?:\\\s*[\[(][^\])]*[\])])?\.(.*)")

# Extracts remap aliases from Mcu.Pin entries, e.g. "PA11 [PA9]" → base=PA11, alias=PA9
_MCU_PIN_RE = re.compile(
    r"^(P[A-K]\d+)(?:-[A-Z_0-9]+)?\s*[\[(](P[A-K]\d+)[\])]$"
)


def parse_ioc(ioc_path):
    """
    Parse a .ioc file and return per-pin configuration and remap info.

    Returns:
        (pins, remaps)

        pins:   {gpio_base_name: {property: value, ...}}
        remaps: {alias_gpio: base_gpio}
                e.g. {'PA9': 'PA11'} means PA11 is remapped to PA9's
                function — PA11 is the physical port for that pin.
    """
    pins = {}
    remaps = {}

    with open(ioc_path, "r", encoding="utf-8") as fh:
        for raw in fh:
            line = raw.strip()
            if "=" not in line:
                continue

            key, _, value = line.partition("=")

            # Mcu.PinXX entries — extract remap aliases
            if key.startswith("Mcu.Pin"):
                m = _MCU_PIN_RE.match(value)
                if m and m.group(1) != m.group(2):
                    # e.g. PA11 [PA9] → remaps["PA9"] = "PA11"
                    remaps[m.group(2)] = m.group(1)
                continue

            m = _GPIO_RE.match(key)
            if not m:
                continue

            full_pin = m.group(1)       # e.g. "PF0-OSC_IN"
            prop     = m.group(2)       # e.g. "Signal"
            base     = full_pin.split("-")[0]  # e.g. "PF0"

            pins.setdefault(base, {})[prop] = value

    return pins, remaps