#!/usr/bin/env python3
"""mpmath O3 for mechanical.statics.offset_load_at_deflection."""
from __future__ import annotations
import json, math, shutil
from pathlib import Path
import mpmath as mp

def pick(inputs, *keys):
    for key in keys:
        if key in inputs and inputs[key] not in (None, ""):
            return mp.mpf(str(inputs[key]))
    return None

def compute(inputs):
    P = pick(inputs, "P", "load", "force", "F")
    a = pick(inputs, "a", "position")
    x = pick(inputs, "x", "station", "s")
    L = pick(inputs, "L", "span", "length")
    E = pick(inputs, "E", "youngs", "modulus")
    I = pick(inputs, "I", "Ix", "inertia")
    b = L - a
    if x <= a:
        delta = (P * b * x * (L * L - b * b - x * x)) / (6 * E * I * L)
    else:
        delta = (P * a * (L - x) * (L * L - a * a - (L - x) * (L - x))) / (6 * E * I * L)
    return {"delta": delta, "P": P, "a": a, "x": x, "L": L, "E": E, "I": I, "b": b}

def row(vid, inputs, kind):
    out = compute(inputs)
    packed = {"id": vid, "kind": kind, "inputs": inputs}
    for k, v in out.items():
        packed[f"{k}_f64"] = float(v)
        packed[f"{k}_decimal"] = mp.nstr(v, 40, strip_zeros=False)
    return packed

def main():
    mp.mp.dps = 80
    here = Path(__file__).resolve().parent
    vectors = [
        row("o3-check", {"P":"48","a":"1","x":"1","L":"4","E":"1","I":"1"}, "check"),
        row("o3-SI", {"P":"1000","a":"1","x":"1","L":"4","E":"200000000000","I":"0.00001"}, "SI"),
        row("o3-alias", {"load":"96","span":"4","modulus":"1","Ix":"1","a":"1","x":"1"}, "alias"),
        row("o3-awkward", {"P":"13.7","a":"1.2","x":"1.5","L":"4","E":"210000","I":"0.83"}, "awkward"),
        row("o3-neg", {"P":"-48","a":"1","x":"1","L":"4","E":"1","I":"1"}, "signed"),
        row("o3-small", {"P":"10","a":"0.5","x":"1","L":"4","E":"1000","I":"0.01"}, "small"),
        row("o3-stiff", {"P":"500","a":"1","x":"2","L":"4","E":"210e9","I":"2e-4"}, "stiff"),
        row("o3-long", {"P":"200","a":"1","x":"1","L":"4","E":"70e9","I":"5e-5"}, "long"),
    ]
    table = {
        "family": "offset_load_at_deflection",
        "generator_id": "offset-load-at-mpmath-o3",
        "generator_version": "1.0.0",
        "seed": "20260927.offset-load-at-o3",
        "mpmath_dps": 80,
        "precision_bits": int(80 * math.log2(10)),
        "library": f"mpmath {mp.__version__}",
        "notes": "offset point load at station (two-piece curve); + O3 mpmath tabulated δ.",
        "vectors": vectors,
    }
    dest = here / "offset-load-at-o3-tables.json"
    dest.write_text(json.dumps(table, indent=2) + chr(10), encoding="utf-8")
    public = here.parents[3] / "public/developers/cvp/reproduce"
    public.mkdir(parents=True, exist_ok=True)
    shutil.copy2(dest, public / "offset-load-at-o3-tables.json")
    shutil.copy2(Path(__file__), public / "generate-offset-load-at-o3.py")
    print(f"wrote {dest} ({len(vectors)} vectors)")

if __name__ == "__main__":
    main()