"""Build a captured ``/dev/iec0`` record stream for the canonical PoC session.

This reproduces the IEC traffic of the PLAN.md §1 BASIC program::

    OPEN 1,4
    PRINT#1,"HELLO WORLD"
    PRINT#1,"LINE TWO"
    CLOSE 1

as a list of :class:`~iecpoc.device.IecRecord`, so the whole userspace decode +
trace path can be exercised on a host with no Pi/kernel. Run this module as a
script to (re)generate ``tests/data/hello_world_session.bin``.
"""

from __future__ import annotations

import os

from iecpoc import device
from iecpoc.device import (
    FLAG_ADDRESSED,
    FLAG_EOI,
    KIND_COMMAND,
    KIND_DATA,
    KIND_EVENT,
    IecRecord,
)

MY_ADDRESS = 4
_PRINTER_CR = 0x0D  # PRINT# terminates each record with a carriage return


class _Builder:
    """Accumulate records with monotonically increasing timestamps."""

    def __init__(self) -> None:
        self.records: list[IecRecord] = []
        self._ts = 0

    def _tick(self, step: int = 1_000) -> int:
        self._ts += step
        return self._ts

    def event(self, code: int, *, addressed: bool = False) -> None:
        flags = FLAG_ADDRESSED if addressed else 0
        self.records.append(IecRecord(KIND_EVENT, code, flags, self._tick()))

    def command(self, value: int, *, addressed: bool = False) -> None:
        flags = FLAG_ADDRESSED if addressed else 0
        self.records.append(IecRecord(KIND_COMMAND, value, flags, self._tick()))

    def data(self, value: int, *, eoi: bool = False) -> None:
        flags = FLAG_EOI if eoi else 0
        # data is always addressed-to-us by definition of reaching LISTENER state
        self.records.append(IecRecord(KIND_DATA, value, flags | FLAG_ADDRESSED, self._tick(20)))

    def data_text(self, text: str) -> None:
        """Send the bytes of an ASCII/PETSCII-compatible string then a CR (EOI)."""
        for ch in text:
            self.data(ord(ch))
        self.data(_PRINTER_CR, eoi=True)


def build_session() -> list[IecRecord]:
    """Return the record list for the canonical four-statement BASIC program."""
    b = _Builder()

    # --- OPEN 1,4 : LISTEN 4, OPEN ch0 ; no filename so no data phase ---------
    b.event(device.EV_IDLE)
    b.event(device.EV_ATN_ASSERTED)
    b.command(0x24, addressed=True)          # LISTEN 4
    b.command(0xF0)                          # OPEN SA=0
    b.event(device.EV_ATN_RELEASED, addressed=True)
    b.event(device.EV_ATN_COMMAND)
    b.command(0x3F)                          # UNLISTEN
    b.event(device.EV_ATN_RELEASED, addressed=False)

    # --- PRINT#1,"HELLO WORLD" -----------------------------------------------
    b.event(device.EV_ATN_ASSERTED)
    b.command(0x24, addressed=True)          # LISTEN 4
    b.command(0x60)                          # DATA (reopen) SA=0
    b.event(device.EV_ATN_RELEASED, addressed=True)
    b.data_text("HELLO WORLD")
    b.event(device.EV_ATN_COMMAND)
    b.command(0x3F)                          # UNLISTEN
    b.event(device.EV_ATN_RELEASED, addressed=False)

    # --- PRINT#1,"LINE TWO" --------------------------------------------------
    b.event(device.EV_ATN_ASSERTED)
    b.command(0x24, addressed=True)          # LISTEN 4
    b.command(0x60)                          # DATA (reopen) SA=0
    b.event(device.EV_ATN_RELEASED, addressed=True)
    b.data_text("LINE TWO")
    b.event(device.EV_ATN_COMMAND)
    b.command(0x3F)                          # UNLISTEN
    b.event(device.EV_ATN_RELEASED, addressed=False)

    # --- CLOSE 1 : LISTEN 4, CLOSE ch0 ---------------------------------------
    b.event(device.EV_ATN_ASSERTED)
    b.command(0x24, addressed=True)          # LISTEN 4
    b.command(0xE0)                          # CLOSE SA=0
    b.event(device.EV_ATN_RELEASED, addressed=False)

    return b.records


CAPTURE_PATH = os.path.join(os.path.dirname(__file__), "data", "hello_world_session.bin")


def write_capture(path: str = CAPTURE_PATH) -> str:
    os.makedirs(os.path.dirname(path), exist_ok=True)
    with open(path, "wb") as fh:
        device.write_records(fh, build_session())
    return path


if __name__ == "__main__":
    print("wrote", write_capture())