#!/usr/bin/env python3
from __future__ import annotations

import datetime
import io
import sys
from pathlib import Path

import click


@click.command()
@click.argument(
    "boardloader",
    type=click.Path(exists=True, dir_okay=False, readable=True, path_type=Path),
)
@click.argument(
    "bootloader",
    type=click.Path(exists=True, dir_okay=False, readable=True, path_type=Path),
)
@click.argument(
    "firmware",
    type=click.Path(exists=True, dir_okay=False, readable=True, path_type=Path),
)
@click.argument(
    "outfile",
    type=click.Path(dir_okay=False, writable=True, path_type=Path),
    required=False,
)
@click.argument(
    "boardloader_start",
    type=click.STRING,
    required=False,
    default="0x08000000",
)
@click.argument(
    "boardloader_end",
    type=click.STRING,
    required=False,
    default="0x0800C000",
)
@click.argument(
    "bootloader_start",
    type=click.STRING,
    required=False,
    default="0x08020000",
)
@click.argument(
    "firmware_start",
    type=click.STRING,
    required=False,
    default="0x08040000",
)
def main(
        boardloader: Path,
        bootloader: Path,
        firmware: Path,
        outfile: Path | None,
        boardloader_start: str,
        boardloader_end: str,
        bootloader_start: str,
        firmware_start: str,
) -> None:
    boardloader_start = int(boardloader_start, 0)
    boardloader_end = int(boardloader_end, 0)
    bootloader_start = int(bootloader_start, 0)
    firmware_start = int(firmware_start, 0)

    if outfile is None:
        today = datetime.date.today().strftime(r"%Y-%m-%d")
        outfile = Path(f"combined-{today}.bin")

    offset = boardloader_start
    out_bytes = io.BytesIO()

    # write boardloader
    offset += out_bytes.write(boardloader.read_bytes())
    if offset > boardloader_end:
        raise Exception("Boardloader too big")

    # zero-pad until next section:
    offset += out_bytes.write(b"\x00" * (bootloader_start - offset))
    assert offset == bootloader_start

    # write bootlaoder
    offset += out_bytes.write(bootloader.read_bytes())
    if offset > firmware_start:
        raise Exception("Bootloader too big")

    # zero-pad until next section:
    offset += out_bytes.write(b"\x00" * (firmware_start - offset))
    assert offset == firmware_start

    # write firmware
    offset += out_bytes.write(firmware.read_bytes())

    # write out contents
    click.echo(f"Writing {outfile} ({offset - boardloader_start} bytes)")
    outfile.write_bytes(out_bytes.getvalue())


if __name__ == "__main__":
    main()