"""End-to-end smoke test for the codegen Python surface.

Builds a decay model (x' = -x, x(0) = 1), runs it in fastsim, generates C via

`sim.to_c(...)`, compiles + runs that C, and checks both agree with e^-1.

Run against a fastsim built with the `codegen` feature (the default wheel /

`maturin develop --features python,codegen`).

"""

import os

import subprocess

import sys

import tempfile

from fastsim import Simulation, Connection

from fastsim.blocks import Integrator, Amplifier

CC = os.environ.get("CC", "gcc")

def build_run(files, main, t_end):

with tempfile.TemporaryDirectory() as d:

for name, src in files.items():

with open(os.path.join(d, name), "w") as f:

f.write(src)

with open(os.path.join(d, "main.c"), "w") as f:

f.write('#include <stdio.h>\n#include "model.h"\n' + main)

cs = [n for n in files if n.endswith(".c")] + ["main.c"]

subprocess.run([CC, *cs, "-O0", "-o", "m.exe", "-lm"], cwd=d, check=True)

out = subprocess.run([os.path.join(d, "m.exe")], capture_output=True, text=True, check=True)

return [float(x) for x in out.stdout.split()]

def main():

integ = Integrator(1.0)

amp = Amplifier(-1.0)

sim = Simulation([integ, amp], [Connection(integ, amp), Connection(amp, integ)])

sim.run(1.0) # assemble + reference run

# Default (Compact) layout.

files = sim.to_c("decay")

assert set(files) == {"model.h", "model.c"}, sorted(files)

print("compact files:", sorted(files))

# Struct ("rtModel") API: entry points are prefixed with the model name so two

# generated models can be linked into one binary without symbol collisions.

c_main = (

"int main(void){decay_t m;decay_init(&m);"

"decay_run(&m,1.0,1e-3);printf(\"%.17g\", m.x[0]);return 0;}\n"

)

(x,) = build_run(files, c_main, 1.0)

import math

assert abs(x - math.exp(-1.0)) < 1e-4, f"compact C x={x} e^-1={math.exp(-1.0)}"

print(f"compact decay: C x(1)={x:.6f} e^-1={math.exp(-1.0):.6f} OK")

# Library layout: 6 files (model/blocks/solver, .h + .c).

lib = sim.to_c("decay", layout="library")

assert set(lib) == {"model.h", "model.c", "blocks.h", "blocks.c", "solver.h", "solver.c"}, sorted(lib)

print("library files:", sorted(lib))

# Bad option -> ValueError.

try:

sim.to_c("decay", layout="libary")

raise SystemExit("expected ValueError for bad layout")

except ValueError as e:

print("bad option raised ValueError:", str(e)[:60])

print("ALL OK")

if __name__ == "__main__":

sys.exit(main())