#!/usr/bin/env python3
"""Expose the SMS diagnostics through a RAM window that can be read over USB.

Drawing counters on the screen turned out to be unreliable: the notification is
overwritten by the normal screen redraw, so a screenshot usually shows nothing even
when reception is happening. Instead the counters are mirrored into the tail of the
raw audio buffer, which the CPS protocol can read out at any moment (area 7).

Layout at rawBuffer[2376..2399]:
    'S' 'M' 'S' 'D'      magic, so a stale buffer cannot be mistaken for data
    u16 bursts           data bursts handed to the assembler
    u16 headers          data headers parsed
    u16 assembled        messages assembled completely
    u16 lastBlocks       block count announced by the last header
    u16 collected        blocks collected for the message in progress
    u16 state            0 = idle, 1 = collecting
    u16 textLen          length of the last extracted text
"""
W = "/home/viktor/ogd77rel/uv_src/OpenGD77_MDUV380_DM1701_20260130/MDUV380_firmware/application"

p = W + "/source/functions/sms.c"
s = open(p).read()

if "SMS_DIAG_OFFSET" in s:
    print("already patched")
    raise SystemExit(0)

s = s.replace('#include "functions/ticks.h"\n',
              '#include "functions/ticks.h"\n#include "functions/sound.h"\n', 1)

anchor = "void smsInit(void)\n"
assert anchor in s
helper = """// Diagnostics mirror: the tail of the raw audio buffer is readable over USB (CPS area 7),
// which is far more dependable than trying to keep text on the screen.
#define SMS_DIAG_OFFSET  2376

static void smsDiagPublish(void)
{
	volatile uint8_t *d = &audioAndHotspotDataBuffer.rawBuffer[SMS_DIAG_OFFSET];
	uint16_t values[7];

	values[0] = diagBursts;
	values[1] = diagHeaders;
	values[2] = diagAssembled;
	values[3] = diagLastBlocks;
	values[4] = blocksCollected;
	values[5] = (uint16_t)rxState;
	values[6] = diagTextLen;

	d[0] = 'S'; d[1] = 'M'; d[2] = 'S'; d[3] = 'D';

	for (uint8_t i = 0; i < 7; i++)
	{
		d[4 + (i * 2)] = (uint8_t)(values[i] & 0xFF);
		d[5 + (i * 2)] = (uint8_t)(values[i] >> 8);
	}
}

"""
s = s.replace(anchor, helper + anchor, 1)

# track the extracted text length too
s = s.replace("static uint8_t           diagLastBlocks = 0;\n",
              "static uint8_t           diagLastBlocks = 0;\nstatic uint16_t          diagTextLen = 0;\n", 1)
s = s.replace("\tlatest.text[t] = '\\0';\n",
              "\tlatest.text[t] = '\\0';\n\tdiagTextLen = t;\n", 1)

# publish on every tick, so a read over USB always sees the current state
s = s.replace("void smsTick(void)\n{\n", "void smsTick(void)\n{\n\tsmsDiagPublish();\n\n", 1)

open(p, "w").write(s)
print("sms.c: diagnostics mirrored into the readable RAM window")