#!/usr/bin/env python3
"""Compile the actual driver handoff function with deterministic queue stubs."""
from pathlib import Path
import shutil
import subprocess
import sys

root = Path(__file__).resolve().parents[1]
source = (root/'components/esp32-camera/driver/cam_hal.c').read_text()
start = source.index('camera_fb_t *cam_take_latest(')
end = source.index('\nvoid cam_give(', start)
function = source[start:end]
out = root/'target/latest-frame-test'
out.mkdir(parents=True, exist_ok=True)
test = r'''
#include <assert.h>
#include <stdint.h>
#include <stddef.h>
#include <stdio.h>
typedef unsigned TickType_t;
typedef struct { int id; } camera_fb_t;
static struct { size_t frame_cnt; } object = {3}, *cam_obj = &object;
static camera_fb_t frames[] = {{0},{1},{2},{3},{4},{5}};
static int calls, releases[6], mode;
static camera_fb_t *cam_take(TickType_t wait) {
    assert(wait == (calls == 0 ? 100 : 0));
    ++calls;
    if (mode == 1 || (mode == 2 && calls == 2)) return NULL;
    assert(calls < 6);
    return &frames[calls];
}
static void cam_give(camera_fb_t *frame) { releases[frame->id]++; }
'''+function+r'''
static void reset(int scenario) {
    mode=scenario; calls=0;
    for(int i=0;i<6;i++) releases[i]=0;
}
int main(void) {
    uint32_t skipped=99;
    // A producer that stays ahead cannot make the drain loop run forever.
    reset(0);
    camera_fb_t *latest=cam_take_latest(100,&skipped);
    assert(calls==3 && latest->id==3 && skipped==2);
    assert(releases[1]==1 && releases[2]==1 && releases[3]==0);
    // An unavailable/invalid newer candidate must not release our valid frame.
    reset(2);
    latest=cam_take_latest(100,&skipped);
    assert(calls==2 && latest->id==1 && skipped==0 && releases[1]==0);
    // A first-frame timeout has no handle to return, and resets the skip count.
    reset(1);
    assert(cam_take_latest(100,&skipped)==NULL && skipped==0 && calls==1);
    // A single capture buffer performs no second, nonblocking acquisition.
    reset(0); object.frame_cnt=1;
    latest=cam_take_latest(100,NULL);
    assert(calls==1 && latest->id==1 && releases[1]==0);
    puts("4 latest-frame ownership and bounded-drain scenarios passed");
}
'''
(out/'latest-frame.c').write_text(test)
compiler = shutil.which('clang') or shutil.which('gcc')
if not compiler:
    sys.exit('A host clang or gcc is required for this optional driver test')
binary = out/('latest-frame.exe' if sys.platform=='win32' else 'latest-frame')
subprocess.run([compiler,'-std=c11','-Wall','-Wextra','-Werror',str(out/'latest-frame.c'),'-o',str(binary)],check=True)
subprocess.run([str(binary)],check=True)