From 35d03d67eb00f56fc9df604085dbe743d606e498 Mon Sep 17 00:00:00 2001
From: Jeremy Jay <jeremy@pbnjay.com>
Date: Mon, 22 Feb 2021 00:01:17 -0500
Subject: [PATCH] expose data types through interface

---
 cmd/grater/main.go |  2 ++
 commonxl/cell.go   | 29 +++++++++++++++++++++++++++--
 commonxl/sheet.go  | 13 ++++++++++++-
 grate.go           |  5 +++++
 simple/simple.go   | 15 +++++++++++++++
 5 files changed, 61 insertions(+), 3 deletions(-)

diff --git a/cmd/grater/main.go b/cmd/grater/main.go
index 6042cbc..3f3e814 100644
--- a/cmd/grater/main.go
+++ b/cmd/grater/main.go
@@ -40,7 +40,9 @@ func main() {
 			}
 
 			for sheet.Next() {
+				//dtypes := sheet.Types()
 				row := sheet.Strings()
+				//fmt.Println(strings.Join(dtypes, "\t"))
 				fmt.Println(strings.Join(row, "\t"))
 			}
 		}
diff --git a/commonxl/cell.go b/commonxl/cell.go
index 3dc54f0..7e81d71 100644
--- a/commonxl/cell.go
+++ b/commonxl/cell.go
@@ -25,6 +25,26 @@ const (
 	StaticCell          // placeholder, internal use only
 )
 
+// String returns a string description of the cell data type.
+func (c CellType) String() string {
+	switch c {
+	case BlankCell:
+		return "blank"
+	case IntegerCell:
+		return "integer"
+	case FloatCell:
+		return "float"
+	case BooleanCell:
+		return "boolean"
+	case DateCell:
+		return "date"
+	case HyperlinkStringCell:
+		return "hyperlink"
+	default: // StringCell, StaticCell
+		return "string"
+	}
+}
+
 // Cell represents a single cell value.
 type Cell []interface{}
 
@@ -85,7 +105,7 @@ var boolStrings = map[string]bool{
 }
 
 // NewCellWithType creates a new cell value with the given type, coercing as necessary.
-func NewCellWithType(value interface{}, t CellType) Cell {
+func NewCellWithType(value interface{}, t CellType, f *Formatter) Cell {
 	c := NewCell(value)
 	if c[1] == t {
 		// fast path if it was already typed correctly
@@ -154,7 +174,12 @@ func NewCellWithType(value interface{}, t CellType) Cell {
 		c[1] = StringCell
 	}
 	if t == DateCell {
-		/// DO THE MAGIC CONVERSION HERE
+		if c[1] == FloatCell {
+			c[0] = f.ConvertToDate(c[0].(float64))
+		} else if c[1] == IntegerCell {
+			c[0] = f.ConvertToDate(float64(c[0].(int64)))
+		}
+		c[1] = DateCell
 	}
 	return c
 }
diff --git a/commonxl/sheet.go b/commonxl/sheet.go
index f8e728e..5b4c81d 100644
--- a/commonxl/sheet.go
+++ b/commonxl/sheet.go
@@ -55,7 +55,7 @@ func (s *Sheet) Put(row, col int, value interface{}, fmtNum uint16) {
 	if !ok || fmtNum == 0 {
 		s.Rows[row][col] = NewCell(value)
 	} else {
-		s.Rows[row][col] = NewCellWithType(value, ct)
+		s.Rows[row][col] = NewCellWithType(value, ct, s.Formatter)
 	}
 	s.Rows[row][col].SetFormatNumber(fmtNum)
 }
@@ -110,6 +110,17 @@ func (s *Sheet) Strings() []string {
 	return res
 }
 
+// Types extracts the data types from the current record into a list.
+// options: "boolean", "integer", "float", "string", "date",
+// and special cases: "blank", "hyperlink" which are string types
+func (s *Sheet) Types() []string {
+	res := make([]string, s.NumCols)
+	for i, cell := range s.Rows[s.CurRow] {
+		res[i] = cell.Type().String()
+	}
+	return res
+}
+
 // Scan extracts values from the current record into the provided arguments
 // Arguments must be pointers to one of 5 supported types:
 //     bool, int64, float64, string, or time.Time
diff --git a/grate.go b/grate.go
index 6ad421a..06d0cc9 100644
--- a/grate.go
+++ b/grate.go
@@ -29,6 +29,11 @@ type Collection interface {
 	// Strings extracts values from the current record into a list of strings.
 	Strings() []string
 
+	// Types extracts the data types from the current record into a list.
+	// options: "boolean", "integer", "float", "string", "date",
+	// and special cases: "blank", "hyperlink" which are string types
+	Types() []string
+
 	// Scan extracts values from the current record into the provided arguments
 	// Arguments must be pointers to one of 5 supported types:
 	//     bool, int64, float64, string, or time.Time
diff --git a/simple/simple.go b/simple/simple.go
index ec45898..0b2149c 100644
--- a/simple/simple.go
+++ b/simple/simple.go
@@ -44,6 +44,21 @@ func (t *simpleFile) Strings() []string {
 	return t.rows[t.iterRow]
 }
 
+// Types extracts the data types from the current record into a list.
+// options: "boolean", "integer", "float", "string", "date",
+// and special cases: "blank", "hyperlink" which are string types
+func (t *simpleFile) Types() []string {
+	res := make([]string, len(t.rows[t.iterRow]))
+	for i, v := range t.rows[t.iterRow] {
+		if v == "" {
+			res[i] = "blank"
+		} else {
+			res[i] = "string"
+		}
+	}
+	return res
+}
+
 // Scan extracts values from the current record into the provided arguments
 // Arguments must be pointers to one of 5 supported types:
 //     bool, int, float64, string, or time.Time