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package stdlib
import (
"encoding/csv"
"fmt"
"io"
"strings"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/function"
)
var CSVDecodeFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "str",
Type: cty.String,
},
},
Type: func(args []cty.Value) (cty.Type, error) {
str := args[0]
if !str.IsKnown() {
return cty.DynamicPseudoType, nil
}
r := strings.NewReader(str.AsString())
cr := csv.NewReader(r)
headers, err := cr.Read()
if err == io.EOF {
return cty.DynamicPseudoType, fmt.Errorf("missing header line")
}
if err != nil {
return cty.DynamicPseudoType, err
}
atys := make(map[string]cty.Type, len(headers))
for _, name := range headers {
if _, exists := atys[name]; exists {
return cty.DynamicPseudoType, fmt.Errorf("duplicate column name %q", name)
}
atys[name] = cty.String
}
return cty.List(cty.Object(atys)), nil
},
Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
ety := retType.ElementType()
atys := ety.AttributeTypes()
str := args[0]
r := strings.NewReader(str.AsString())
cr := csv.NewReader(r)
cr.FieldsPerRecord = len(atys)
// Read the header row first, since that'll tell us which indices
// map to which attribute names.
headers, err := cr.Read()
if err != nil {
return cty.DynamicVal, err
}
var rows []cty.Value
for {
cols, err := cr.Read()
if err == io.EOF {
break
}
if err != nil {
return cty.DynamicVal, err
}
vals := make(map[string]cty.Value, len(cols))
for i, str := range cols {
name := headers[i]
vals[name] = cty.StringVal(str)
}
rows = append(rows, cty.ObjectVal(vals))
}
if len(rows) == 0 {
return cty.ListValEmpty(ety), nil
}
return cty.ListVal(rows), nil
},
})
// CSVDecode parses the given CSV (RFC 4180) string and, if it is valid,
// returns a list of objects representing the rows.
//
// The result is always a list of some object type. The first row of the
// input is used to determine the object attributes, and subsequent rows
// determine the values of those attributes.
func CSVDecode(str cty.Value) (cty.Value, error) {
return CSVDecodeFunc.Call([]cty.Value{str})
}
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