unit GridProcs;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, Grids,
  Globals, DictionaryUnit;

function CollectValues(AGrid: TStringGrid; AColIndex: Integer;
  AColCheck: IntDyneVec = nil): DblDyneVec;

procedure GetMinMax(AGrid: TStringGrid; AColIndex: Integer;
  const AColCheck: IntDyneVec; out AMin, AMax: Double);

function GoodRecord(AGrid: TStringGrid; ARow: integer;
  const AColCheck: IntDyneVec): boolean;

function IsEmptyNumericValue(AGrid: TStringGrid; ARow, ACol: Integer): Boolean;

function IsFiltered(AGrid: TStringGrid; ARow: integer): boolean;

function IsMissingValueCode(AGrid: TStringGrid; ARow, ACol: Integer): Boolean;

function ValidValue(AGrid: TStringGrid; ARow, ACol: integer): boolean;


implementation

uses
  Math;

{ Extracts the values in the given column from the grid and returns them as an
  array.
  Cells which are filtered or empty are not considered. This check is extended
  over all columns specified by the column indices in AColCheck; AColCheck
  should be empty to consider only the current column.
  Non-numeric values in the considered cell will raise an exception.

  NOTE: AColCheck must not be overdimensioned! }
function CollectValues(AGrid: TStringGrid; AColIndex: Integer; AColCheck: IntDyneVec): DblDyneVec;
var
  row, n: Integer;
  val: Double;
begin
  SetLength(Result, AGrid.RowCount);
  n := 0;
  for row := 1 to AGrid.RowCount-1 do
  begin
    if Length(AColCheck) = 0 then
    begin
      if not ValidValue(AGrid, row, AColIndex) then continue;
    end else
    begin
      if not GoodRecord(AGrid, row, AColCheck) then continue;
    end;
    if TryStrToFloat(trim(AGrid.Cells[AColIndex, row]), val) then
      Result[n] := val
    else
      raise ELazStats.CreateFmt('Non-numeric string "%s" in column %d, row %d',
        [AGrid.Cells[AColIndex, row], AColIndex, row]);
    inc(n);
  end;
  SetLength(Result, n);
end;


{ Determines the minimum and maximum of the values in the specified column of
  the grid. Rows with "invalid" data are ignored. If AColCheck contains other
  column indices these cells must be "valid", too. }
procedure GetMinMax(AGrid: TStringGrid; AColIndex: Integer;
  const AColCheck: IntDyneVec; out AMin, AMax: Double);
var
  row: Integer;
  value: Double;
begin
  AMin := Infinity;
  AMax := -Infinity;
  for row := 1 to AGrid.RowCount-1 do
  begin
    if Length(AColCheck) = 0 then
    begin
      if not ValidValue(AGrid, row, AColIndex) then continue;
    end else
    begin
      if not GoodRecord(AGrid, row, AColCheck) then continue;
    end;
    value := StrToFloat(trim(AGrid.Cells[AColIndex, row]));
    if value < AMin then AMin := value;
    if value > AMax then AMax := value;
  end;
end;


{ Checks whether all cells specified for the given row in the columns listed in
  the GridPos array are "valid": not filtered and not empty }
function GoodRecord(AGrid: TStringGrid; ARow: integer;
  const AColCheck: IntDyneVec): boolean;
var
  i, j: integer;
begin
  Result := true;
  for i := 0 to High(AColCheck) do
  begin
    j := AColCheck[i];
    if not ValidValue(AGrid, ARow, j) then
      Result := false;
  end;
end;


{ Checks whether the cell in the given row in the given numeric column is empty. }
function IsEmptyNumericValue(AGrid: TStringGrid; ARow, ACol: Integer): Boolean;
var
  value: String;
  isStringField: Boolean;
begin
  value := Trim(AGrid.Cells[ACol, ARow]);
  isStringField := DictionaryFrm.DictGrid.Cells[4, ACol] = 'S';
  Result := not IsStringField and (value = '');
end;


{ Checks whether the specified row is "filtered". Two criteria are needed for
  a row to be filtered:
  - The cell in column FilterCol (global value) must contain the text 'NO'.
  - The global variable "FilterOn" must be TRUE. }
function IsFiltered(AGrid: TStringGrid; ARow: integer): boolean;
begin
  Result := FilterOn and (Trim(AGrid.Cells[FilterCol, ARow]) = 'NO');
end;


{ Checks whether specified cell contains the "missing value code" defined by
  the Dictionary }
function IsMissingValueCode(AGrid: TStringGrid; ARow, ACol: Integer): Boolean;
var
  missingCode: String;
  value: String;
begin
  missingCode := Trim(DictionaryFrm.DictGrid.Cells[6, ACol]);
  value := Trim(AGrid.Cells[ACol, ARow]);
  Result := (value = missingCode);
end;


{ Checks wheter the value in cell at the given column and row is a not-filtered,
  non-empty number.
  NOTE: non-numeric characters in a numeric field are not taken into account! }
function ValidValue(AGrid: TStringGrid; ARow, ACol: integer): boolean;
begin
  Result := not (
    IsFiltered(AGrid, ARow) or                 // filtering is active and row is marked to be excluded
    IsEmptyNumericValue(AGrid, ARow, aCol) or  // column is numeric, but cell is empty
    IsMissingValueCode(AGrid, ARow, ACol)      // cell contains the "missing value code"
  );
end;


end.