backend/main.py

from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
import httpx
import pyproj
from typing import List, Dict, Optional, Any
from distance import calculate_distance
from area import calculate_area
from coordinate_converter import convert_coordinates
from terrain import extract_terrain_data

app = FastAPI(title="GIS Tools API")

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

# Define request and response models
class CoordinateRequest(BaseModel):
    latitude: float
    longitude: float
    crs: str = "EPSG:4326"

class ElevationResponse(BaseModel):
    latitude: float
    longitude: float
    elevation: float
    wgs84_latitude: float
    wgs84_longitude: float
    original_crs: str

class CRSInfo(BaseModel):
    code: str
    name: str

class DistanceRequest(BaseModel):
    point1: CoordinateRequest
    point2: CoordinateRequest

class AreaRequest(BaseModel):
    coordinates: List[CoordinateRequest]

class TerrainRequest(BaseModel):
    latitude: float
    longitude: float
    crs: str = "EPSG:4326"

# Helper: Convert to WGS84
def convert_to_wgs84(lon, lat, source_crs):
    if source_crs == "EPSG:4326":
        return (lon, lat)
    try:
        transformer = pyproj.Transformer.from_crs(source_crs, "EPSG:4326", always_xy=True)
        lon, lat = transformer.transform(lon, lat)
        return (lon, lat)
    except Exception as e:
        raise Exception(f"Coordinate transformation error: {str(e)}")

# Helper: Query Open-Meteo
async def query_open_meteo(lat, lon):
    url = f"https://api.open-meteo.com/v1/elevation?latitude={lat}&longitude={lon}"
    async with httpx.AsyncClient() as client:
        try:
            response = await client.get(url)
            response.raise_for_status()
            data = response.json()
            if "elevation" in data and isinstance(data["elevation"], list) and len(data["elevation"]) > 0:
                return float(data["elevation"][0])
            else:
                raise Exception("No elevation data found in API response")
        except httpx.HTTPStatusError as e:
            raise Exception(f"Elevation API error: {str(e)}")
        except Exception as e:
            raise Exception(f"Error querying elevation: {str(e)}")

# Route for fetching elevation data
@app.post("/api/elevation", response_model=ElevationResponse)
async def get_elevation(request: CoordinateRequest):
    try:
        wgs84_coords = convert_to_wgs84(request.longitude, request.latitude, request.crs)
        elevation = await query_open_meteo(wgs84_coords[1], wgs84_coords[0])
        return ElevationResponse(
            latitude=request.latitude,
            longitude=request.longitude,
            elevation=elevation,
            wgs84_latitude=wgs84_coords[1],
            wgs84_longitude=wgs84_coords[0],
            original_crs=request.crs
        )
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

# Route for calculating distance
@app.post("/api/distance")
async def calculate_distance_route(request: DistanceRequest):
    # Extract coordinates and CRS
    p1 = (request.point1.longitude, request.point1.latitude, request.point1.crs)
    p2 = (request.point2.longitude, request.point2.latitude, request.point2.crs)
    return {"distance": calculate_distance(p1, p2)}

# Route for calculating area
@app.post("/api/area")
async def calculate_area_route(request: AreaRequest):
    # Convert CoordinateRequest list to list of (lon, lat, crs)
    coords = [(c.longitude, c.latitude, c.crs) for c in request.coordinates]
    return {"area": calculate_area(coords)}

# Route for converting coordinates
@app.post("/api/coordinate-converter")
async def coordinate_converter_route(request: CoordinateRequest):
    return convert_coordinates(request.longitude, request.latitude, request.crs)

# Route for extracting terrain data
@app.post("/api/terrain")
async def terrain_data_route(request: TerrainRequest):
    return await extract_terrain_data(request.latitude, request.longitude, request.crs)

# Route for fetching CRS list
@app.get("/api/crs-list", response_model=List[CRSInfo])
async def get_crs_list():
    crs_list = [
        {"code": "EPSG:4326", "name": "WGS 84"},
        {"code": "EPSG:3857", "name": "Web Mercator"},
        {"code": "EPSG:2154", "name": "RGF93 / Lambert-93"},
        {"code": "EPSG:27700", "name": "OSGB 1936 / British National Grid"},
        {"code": "EPSG:3785", "name": "Popular Visualisation CRS / Mercator"},
        {"code": "EPSG:4269", "name": "NAD83"},
        {"code": "EPSG:4267", "name": "NAD27"},
        {"code": "EPSG:32633", "name": "WGS 84 / UTM zone 33N"},
    ]
    return crs_list

# Health check endpoint
@app.get("/api/health")
async def health_check():
    return {"status": "ok"}

if __name__ == "__main__":
    import uvicorn
    import os
    port = int(os.environ.get("PORT", 7860))
    uvicorn.run(app, host="0.0.0.0", port=port)