from flask import session
from app.utils.helper import is_ajax, get_response, validate_latlon, coordinates_match
import pandas as pd


class CoordinateController:
    MAX_LIMIT = 30

    @staticmethod
    def add_coordinate(lat, lon, coordinates, request):
        """Add a coordinate to the session."""

        try:
            lat, lon = validate_latlon(lat, lon)
        except ValueError:
            return get_response("Invalid coordinates. Please enter valid numbers.", "error", 400, is_ajax(request))

        if len(coordinates) >= CoordinateController.MAX_LIMIT:
            return get_response(f"Maximum {CoordinateController.MAX_LIMIT} coordinates allowed.", "error", 400, is_ajax(request))

        if any(coordinates_match(c, lat, lon) for c in coordinates):
            return get_response("Coordinate already exists.", "warning", 400, is_ajax(request))

        coordinates.append({"lat": lat, "lon": lon})
        session["coordinates"] = coordinates
        session["map_center"] = {"lat": lat, "lon": lon}
        session.modified = True

        return get_response(
            "Coordinate added successfully!",
            "success",
            200,
            is_ajax(request),
            {"lat": lat, "lon": lon}
        )

    @staticmethod
    def delete_coordinate(lat, lon):
        """Delete coordinate by lat/lon"""
        try:
            lat = float(lat)
            lon = float(lon)
        except ValueError:
            return get_response("Invalid coordinates.", "error", 400)

        coords = session.get("coordinates", [])
        
        new_list = [c for c in coords if not coordinates_match(c, lat, lon)]

        session["coordinates"] = new_list
        session.modified = True
        
        return get_response("Coordinate deleted successfully!", "success", 200, extra={"coordinates": new_list})

    @staticmethod
    def clear_all(request):
        """Clear all coordinates"""

        session["coordinates"] = []
        session.modified = True

        return get_response(
            "All coordinates cleared!",
            "success",
            200,
            is_ajax(request),
            extra={"coordinates": []}
        )

    @staticmethod

    def upload_coordinates(file_obj, request):
        """Upload coordinates from a CSV file, supporting flexible column naming."""

        if not file_obj or file_obj.filename == "":
            return get_response("No file selected.", "error", 400, is_ajax(request))

        if not file_obj.filename.endswith(".csv"):
            return get_response("Invalid file format. Please upload a CSV file.", "error", 400, is_ajax(request))

        # 1. Read CSV
        try:
            df = pd.read_csv(file_obj)
        except Exception as e:
            return get_response(f"Error reading CSV: {str(e)}", "error", 500, is_ajax(request))

        # 2. Normalize column names
        df.columns = df.columns.str.strip().str.lower()

        # 3. Possible matching names
        lat_candidates = ["latitude", "lat", "x", "y_lat", "latitude (deg)"]
        lon_candidates = ["longitude", "lon", "lng", "long", "y", "x_lon", "longitude (deg)"]

        # 4. Detect actual columns
        lat_col = next((c for c in df.columns if any(key in c for key in lat_candidates)), None)
        lon_col = next((c for c in df.columns if any(key in c for key in lon_candidates)), None)

        if not lat_col or not lon_col:
            return get_response(
                "CSV must contain recognizable latitude/longitude columns. "
                "Examples: latitude, lat, Latitude, LAT, lon, longitude",
                "error",
                400,
                is_ajax(request)
            )

        # 5. Process coordinates
        coordinates = []
        new_count = 0
        invalid_count = 0
        duplicates_count = 0

        for _, row in df.iterrows():
            try:
                lat, lon = validate_latlon(row[lat_col], row[lon_col])
            except ValueError:
                invalid_count += 1
                continue

            if len(coordinates) >= CoordinateController.MAX_LIMIT:
                break

            if any(coordinates_match(c, lat, lon) for c in coordinates):
                duplicates_count += 1
                continue

            coordinates.append({"lat": lat, "lon": lon})
            new_count += 1

        # 6. Save to session
        session["coordinates"] = coordinates
        session.modified = True

        msg = (
            f"Successfully added {new_count} new coordinates. "
            f"{invalid_count} invalid coordinates ignored. "
            f"{duplicates_count} duplicates ignored."
        )

        return get_response(msg, "success", 200, is_ajax(request), extra={"coordinates": coordinates})