from fastapi import FastAPI, UploadFile, File
from fastapi.responses import JSONResponse, FileResponse
from fastapi.middleware.cors import CORSMiddleware
import os

app = FastAPI()

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"], allow_credentials=True,
    allow_methods=["*"], allow_headers=["*"],
)

@app.get("/")
def serve_frontend():
    return FileResponse("index.html")

@app.post("/parse")
async def parse_file(file: UploadFile = File(...)):
    content = await file.read()
    return JSONResponse(content=parse_dcm_assembly(content))

def parse_dcm_assembly(file_bytes):
    lines = file_bytes.decode("utf-8").splitlines()
    blocks, current = [], []

    for line in lines:
        if line.startswith("CLASS"):
            if current:
                blocks.append(current)
                current = []
        current.append(line.strip())
    if current: blocks.append(current)

    parts, geometry, constraints = [], {}, []
    plane_map, tag_to_plane, label_map = {}, {}, {}

    for block in blocks:
        head = block[0]
        if "CLASS SET " in head:
            part, members = {}, []
            for line in block:
                if "DCM3_TEXT_LABEL" in line:
                    part['name'] = line.split("DCM3_TEXT_LABEL", 1)[1].strip()
                elif "FMEMBER TAGS" in line:
                    members = list(map(int, line.split()[2:]))
            if 'name' in part:
                part['member_tags'] = members
                parts.append(part)

        elif "CLASS PLANE " in head:
            pid = int(head.split()[-1])
            base, norm = None, None
            for line in block:
                if "FBASE_POINT" in line:
                    base = tuple(map(float, line.split()[1:]))
                elif "FNORMAL" in line:
                    norm = tuple(map(float, line.split()[1:]))
            if base and norm:
                plane_map[pid] = {'base_point': base, 'normal': norm}

        elif "CLASS WORK_PLANE " in head:
            wid = int(head.split()[-1])
            tag, label = None, None
            for line in block:
                if "FMY_PLANE TAG" in line:
                    tag = int(line.split()[-1])
                elif "DCM3_TEXT_LABEL" in line:
                    label = line.split("DCM3_TEXT_LABEL", 1)[1].strip()
            if tag:
                tag_to_plane[wid] = tag
                label_map[wid] = label

        elif "CLASS CONSTRAINT " in head:
            con = {}
            for line in block:
                if "FEND_1 TAG" in line:
                    con['from'] = int(line.split()[-1])
                elif "FEND_2 TAG" in line:
                    con['to'] = int(line.split()[-1])
                elif "DCM3_TEXT_LABEL" in line:
                    con['label'] = line.split("DCM3_TEXT_LABEL", 1)[1].strip()
            if con: constraints.append(con)

    for wid, pid in tag_to_plane.items():
        if pid in plane_map:
            geometry[wid] = {**plane_map[pid], 'label': label_map.get(wid)}

    return { "parts": parts, "geometry": geometry, "constraints": constraints }