public async Task <List <string> > FindPostcodesInRadiusKm(string startingPostcode, PostcodePartsType startingPostcodeType, double radiusInKm, bool excludeBoatRides, bool avoidClippingOtherSideBristolChannel)
{
if (_lookupData == null || !_lookupData.Any())
{
throw new InvalidOperationException("Must initialize the data first");
}
List <string> postcodesInRadius = new List <string>();
// 1. Break the postcode down to the bit we need.
PostcodeParts postcode = new PostcodeParts(startingPostcode, startingPostcodeType);
var areaAndDistrict = postcode.GetAreaAndDistrict_10K(); // E.g. PO4
// 2. Get lat long for the postcode entered.
var startingLatLong = _lookupData.FirstOrDefault(_ => _.Identifier == areaAndDistrict);
if (startingLatLong == null)
{
throw new InvalidOperationException($"Could not find location for postcode {startingPostcode} -> {areaAndDistrict}");
}
var startingLocation = new Coordinate(startingLatLong.Latitude, startingLatLong.Longitude);
// 3. Loop through all the postcodes to find ones in the radius.
foreach (var loc in _lookupData)
{
var compareLocation = new Coordinate(loc.Latitude, loc.Longitude);
var distanceInKm = GeoCalculator.GetDistance(startingLocation, compareLocation, 2, DistanceUnit.Kilometers);
if (distanceInKm < radiusInKm)
{
postcodesInRadius.Add(loc.Identifier);
}
}
if (excludeBoatRides)
{
var islandAreaPostcodes = NoFastRoutePostcodes.GetIslands_WithOwnAreaPostcodes();
var islandAreaDistrictPostcodes = NoFastRoutePostcodes.GetIslands_WithAreaDistrictPostcodes();
bool isStartPointAnIsland = false;
var startingPostcodeParts = new PostcodeParts(startingPostcode, startingPostcodeType);
var startingPostcodeArea = startingPostcodeParts.GetArea_250K();
var startingPostcodeAreaDistrict = startingPostcodeParts.GetAreaAndDistrict_10K();
var isIslandAreaMatch = islandAreaPostcodes.FirstOrDefault(_ => _ == startingPostcodeArea) != null;
var isIslandAreaDistrictmatch = islandAreaDistrictPostcodes.FirstOrDefault(_ => _ == startingPostcodeAreaDistrict) != null;
bool isStartingPointAnIsland = isIslandAreaMatch || isIslandAreaDistrictmatch;
// Exclude Water Crossings - Kept Simple
if (isStartingPointAnIsland)
{
// Only Keep postcodes in same Area code (cross island e.g. Jersey (JE)/Guernsey (GY))
postcodesInRadius = postcodesInRadius.Where(_ => _.StartsWith(startingPostcodeArea)).ToList();
// Then remove anything that isn't in the island postcode area/district list (.e.g. IoW -> PO33 OK, PO5 (pompey) not.
postcodesInRadius = postcodesInRadius.Where(_ => islandAreaDistrictPostcodes.Contains(_)).ToList();
}
else
{
// Starting on the mainland - Remove any Island postcode area (e.g. starting at IV [inverness], excluding HS [hebrides])
List <string> goodPostcodes = new List <string>();
foreach (var row in postcodesInRadius)
{
var rowParts = new PostcodeParts(row, PostcodePartsType.AreaAndDistrict);
var area = rowParts.GetArea_250K();
if (!islandAreaPostcodes.Contains(area))
{
goodPostcodes.Add(row);
}
}
postcodesInRadius = goodPostcodes;
// Remove anything that starts with islandAreaPostcodes or is in islandAreaDistrictPostcodes (can simplify as district in lookup data)
postcodesInRadius = postcodesInRadius.Where(_ => !islandAreaDistrictPostcodes.Contains(_)).ToList();
}
}
if (avoidClippingOtherSideBristolChannel)
{
var startingPostcodeParts = new PostcodeParts(startingPostcode, startingPostcodeType);
var startingPostcodeArea = startingPostcodeParts.GetArea_250K();
var englandSWalesPostcodeAreas = NoFastRoutePostcodes.GetEngWalesPostcodes_Areas_SplitByWater();
var gloucester = NoFastRoutePostcodes.GetGloucester_AreaDistrics_SplitByWater();
var isStartSWEngland = false;
foreach (var row in englandSWalesPostcodeAreas.OneSide) // ONESIDE = ENG
{
if (row == startingPostcodeArea)
{
isStartSWEngland = true;
break;
}
}
if (isStartSWEngland)
{
// If we're starting in England, Remove any postcodes that have welsh starters (e.g. CF, NP)
List <string> goodPostcodes = new List <string>();
foreach (var row in postcodesInRadius)
{
var rowParts = new PostcodeParts(row, PostcodePartsType.AreaAndDistrict);
var area = rowParts.GetArea_250K();
if (!englandSWalesPostcodeAreas.OtherSide.Contains(area))
{
goodPostcodes.Add(row);
}
}
postcodesInRadius = goodPostcodes;
// We're in England, so remove the Welsh Gloucester Postcodes (Area+District, so easy to handle).
postcodesInRadius = postcodesInRadius.Where(_ => !gloucester.OtherSide.Contains(_)).ToList();
}
var isStartSouthWales = false;
foreach (var row in englandSWalesPostcodeAreas.OtherSide) // OtherSide = WALES
{
if (row == startingPostcodeArea)
{
isStartSouthWales = true;
break;
}
}
if (isStartSouthWales)
{
// If we're starting in Wales, Remove any postcodes that have English starters (e.g. BS, TR)
List <string> goodPostcodes = new List <string>();
foreach (var row in postcodesInRadius)
{
var rowParts = new PostcodeParts(row, PostcodePartsType.AreaAndDistrict);
var area = rowParts.GetArea_250K();
if (!englandSWalesPostcodeAreas.OneSide.Contains(area))
{
goodPostcodes.Add(row);
}
}
postcodesInRadius = goodPostcodes;
// We're in Wales, so remove the English Gloucester Postcodes (Area+District, so easy to handle).
postcodesInRadius = postcodesInRadius.Where(_ => !gloucester.OneSide.Contains(_)).ToList();
}
//var southWalesAreaPostcodes = NoFastRoutePostcodes.GetWales_ClippableAreaPostcodes();
//var southWalesAreaDistrictPostcodes = NoFastRoutePostcodes.GetWales_ClippableAreaDistricts();
//var startingPostcodeParts = new PostcodeParts(startingPostcode, startingPostcodeType);
//var startingPostcodeArea = startingPostcodeParts.GetArea_250K();
//var startingPostcodeAreaDistrict = startingPostcodeParts.GetAreaAndDistrict_10K();
//var isSWalesAreaMatch = southWalesAreaPostcodes.FirstOrDefault(_ => _ == startingPostcodeArea) != null;
//var isSWalesAreaDistrictmatch = southWalesAreaDistrictPostcodes.FirstOrDefault(_ => _ == startingPostcodeAreaDistrict) != null;
//bool isStartingPointInWales = isSWalesAreaMatch || isSWalesAreaDistrictmatch;
//// Avoid River Severn/Bristol Channel Crossings
//if (isStartingPointInWales)
//{
// // Only Keep postcodes in same Area code (cross island e.g. Jersey (JE)/Guernsey (GY))
// postcodesInRadius = postcodesInRadius.Where(_ => _.StartsWith(startingPostcodeArea)).ToList();
// // Then remove anything that isn't in the island postcode area/district list (.e.g. IoW -> PO33 OK, PO5 (pompey) not.
// postcodesInRadius = postcodesInRadius.Where(_ => southWalesAreaDistrictPostcodes.Contains(_)).ToList();
//}
//else
//{
// // Starting on the mainland
// postcodesInRadius = postcodesInRadius.Where(_ => !islandAreaPostcodes.Contains(startingPostcodeArea)).ToList();
// // Remove anything that starts with islandAreaPostcodes or is in islandAreaDistrictPostcodes
// postcodesInRadius = postcodesInRadius.Where(_ => !islandAreaDistrictPostcodes.Contains(_)).ToList();
//}
}
// 4. Return list
return(postcodesInRadius);
}
