"""Trikona custom-frontend server (gradio.Server) — parallel to app.py.

Serves a fully custom UI at / that calls the /generate and /regenerate API
endpoints via the Gradio JS client. The frontend renders shapes IN PLACE (no
iframe reload, no postMessage->hidden-button bridge), so the camera/orbit state
persists and there is no white flash between shapes.

Reuses app.py's generation core (codegen pipeline / mesh / raw) and its flags +
caches, so behavior matches the Blocks app. The Modal endpoint URLs stay
server-side (the browser only ever calls /generate and /regenerate).

Run:  TRIKONA_CODEGEN=1 MODAL_ENDPOINT_URL=... python3 server.py
The original app.py (Blocks + iframe) is untouched and still works.
"""
import json
import os
from pathlib import Path

import gradio as gr
from fastapi.responses import HTMLResponse

import app as core  # generation logic, flags (CODEGEN/MESH_ON), endpoint URLs, caches

HERE = Path(__file__).parent
CANVAS_HTML = (HERE / "canvas.html").read_text()
INDEX_HTML = (HERE / "web" / "index.html").read_text()

server = gr.Server(title="Trikona")


def _generate(prompt: str, params=None) -> dict:
    """Return {"contract": <json str>, "status": <tier>} reusing app.py's core."""
    if not core.CODEGEN:
        return {"contract": core.generate_shape(prompt, params=params), "status": "raw"}
    from geometry import pipeline
    mesh_fn = core._mesh_emit if (core.MESH_ON and core.MESH_URL) else None
    result, meta = pipeline.build(core._model_emit, prompt, params=params, mesh_fn=mesh_fn)
    if meta.get("spec") is not None:
        core._SPEC_CACHE[prompt] = meta["spec"]
    return {"contract": json.dumps(result), "status": meta.get("status", "ok")}


@server.api(name="generate")
def generate(prompt: str) -> str:
    prompt = (prompt or "").strip()
    if not prompt:
        return json.dumps({"contract": json.dumps({"error": "empty_prompt"}), "status": "error"})
    if len(prompt) > core.MAX_PROMPT_CHARS:
        return json.dumps({"contract": json.dumps({"error": "prompt_too_long"}), "status": "error"})
    return json.dumps(_generate(prompt))


@server.api(name="regenerate")
def regenerate(prompt: str, params: str) -> str:
    """Topological regen. params is a JSON object of param values (or empty)."""
    prompt = (prompt or "").strip()
    try:
        p = json.loads(params) if params else None
    except (json.JSONDecodeError, TypeError):
        p = None
    if core.CODEGEN:
        spec = core._SPEC_CACHE.get(prompt)
        if spec is not None:
            try:
                out = core._regen_modelfree(spec, p)
                if out is not None:
                    return json.dumps({"contract": out, "status": "regen"})
            except Exception:
                pass
    return json.dumps(_generate(prompt, params=p))


@server.api(name="examples")
def examples() -> str:
    return json.dumps(core.EXAMPLE_PROMPTS)


@server.get("/", response_class=HTMLResponse)
def home():
    return INDEX_HTML


@server.get("/canvas", response_class=HTMLResponse)
def canvas():
    return CANVAS_HTML


if __name__ == "__main__":
    server.launch(server_name="0.0.0.0",
                  server_port=int(os.environ.get("PORT", "7860")))