#!/usr/bin/python3

import re
import sys
import subprocess
from pathlib import Path

# pylint: disable=invalid-name

### Sanity/usage checks

if len(sys.argv) != 3:
    print("E: need 2 arguments", file=sys.stderr)
    sys.exit(1)

arch = sys.argv[1]
if arch not in ['armhf', 'arm64']:
    print("E: unsupported arch %s" % arch, file=sys.stderr)
    sys.exit(1)

suite = sys.argv[2]
if suite not in ['bookworm', 'trixie', 'forky', 'sid']:
    print("E: unsupported suite %s" % suite, file=sys.stderr)
    sys.exit(1)
target_yaml = 'raspi_%s_%s.yaml' % (arch, suite)


### Setting variables based on suite and version starts here

# Arch, kernel, DTB:
if arch == 'armhf':
    arch = 'armhf'
    linux = 'linux-image-armmp'
    dtb = '/usr/lib/linux-image-*-armmp/bcm*rpi*.dtb'
elif arch == 'arm64':
    linux = 'linux-image-arm64'
    dtb = '/usr/lib/linux-image-*-arm64/broadcom/bcm*rpi*.dtb'

# wireless/bluetooth firmware:
if arch != 'armhf':
    wireless_firmware = 'firmware-brcm80211'
    bluetooth_firmware = 'bluez-firmware'
else:
    wireless_firmware = ''
    bluetooth_firmware = ''

# Pi 4 on buster required some backports. Let's keep variables around, ready to
# be used whenever we need to pull specific things from backports.
backports_enable = False
backports_suite = '%s-backports' % suite

# Serial console:
if arch == 'armhf':
    serial = 'ttyAMA0,115200'
elif arch == 'arm64':
    serial = 'ttyS1,115200'

# CMA fixup:
extra_chroot_shell_cmds = []
if arch == 'arm64':
    extra_chroot_shell_cmds = [
        "sed -i 's/cma=64M //' /boot/firmware/cmdline.txt",
    ]

# Hostname:
hostname = 'rpi-%s' % arch

# Nothing yet!
extra_root_shell_cmds = []


### The following prepares substitutions based on variables set earlier

# Enable backports with a reason, or add commented-out entry:
if backports_enable:
    backports_stanza = """
%s
deb http://deb.debian.org/debian/ %s main non-free-firmware
""" % (backports_enable, backports_suite)
else:
    # ugh
    backports_stanza = """
# Backports are _not_ enabled by default.
# Enable them by uncommenting the following line:
# deb http://deb.debian.org/debian %s main non-free-firmware
""" % backports_suite

# Enable updates and security for everyone but sid:
if suite != 'sid':
    updates_stanza = 'deb http://deb.debian.org/debian %s-updates main non-free-firmware' % suite
    security_stanza = 'deb http://security.debian.org/debian-security %s-security main non-free-firmware' % suite
else:
    updates_stanza = ''
    security_stanza = ''


gitcommit = subprocess.getoutput("git show -s --pretty='format:%C(auto)%h (%s, %ad)' --date=short ")
buildtime = subprocess.getoutput("date --utc +'%Y-%m-%d %H:%M'")

### Write results:

def align_replace(text, pattern, replacement):
    """
    This helper lets us keep the indentation of the matched pattern
    with the upcoming replacement, across multiple lines. Naive
    implementation, please make it more pythonic!
    """
    lines = text.splitlines()
    for i, line in enumerate(lines):
        m = re.match(r'^(\s+)%s' % pattern, line)
        if m:
            indent = m.group(1)
            del lines[i]
            for r in replacement:
                lines.insert(i, '%s%s' % (indent, r))
                i = i + 1
            break
    return '\n'. join(lines) + '\n'


with open('raspi_master.yaml', 'r') as in_file:
    with open(target_yaml, 'w') as out_file:
        in_text = in_file.read()
        out_text = in_text \
            .replace('__RELEASE__', suite) \
            .replace('__ARCH__', arch) \
            .replace('__LINUX_IMAGE__', linux) \
            .replace('__DTB__', dtb) \
            .replace('__WIRELESS_FIRMWARE__', wireless_firmware) \
            .replace('__BLUETOOTH_FIRMWARE__', bluetooth_firmware) \
            .replace('__SERIAL_CONSOLE__', serial) \
            .replace('__HOST__', hostname) \
            .replace('__GITCOMMIT__', gitcommit) \
            .replace('__BUILDTIME__', buildtime)

        out_text = align_replace(out_text, '__EXTRA_ROOT_SHELL_CMDS__', extra_root_shell_cmds)
        out_text = align_replace(out_text, '__EXTRA_CHROOT_SHELL_CMDS__', extra_chroot_shell_cmds)
        out_text = align_replace(out_text, '__UPDATES_', updates_stanza.splitlines())
        out_text = align_replace(out_text, '__BACKPORTS__', backports_stanza.splitlines())
        out_text = align_replace(out_text, '__SECURITY__', security_stanza.splitlines())

        # Try not to keep lines where the placeholder was replaced
        # with nothing at all (including on a "list item" line):
        filtered = [x for x in out_text.splitlines()
                    if not re.match(r'^\s+$', x)
                    and not re.match(r'^\s+-\s*$', x)]
        out_file.write('\n'.join(filtered) + "\n")