1 files changed, 176 insertions, 0 deletions
diff --git a/pkg/query/outputs.go b/pkg/query/outputs.go
new file mode 100644
index 0000000..a18fd16
--- /dev/null
+++ b/pkg/query/outputs.go
@@ -0,0 +1,176 @@
+package query
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/jpappel/atlas/pkg/index"
+)
+
+var ErrUnrecognizedOutputToken = errors.New("Unrecognized output token")
+var ErrExpectedMoreStringTokens = errors.New("Expected more string tokens")
+
+const DefaultOutputFormat string = "%p %T %d authors:%a tags:%t"
+
+type OutputToken uint64
+
+// TODO: support long token names
+const (
+	OUT_TOK_STR      OutputToken = iota
+	OUT_TOK_PATH                 // %p %path
+	OUT_TOK_TITLE                // %T %title
+	OUT_TOK_DATE                 // %d %date
+	OUT_TOK_FILETIME             // %f %filetime
+	OUT_TOK_AUTHORS              // %a %authors
+	OUT_TOK_TAGS                 // %t %tags
+	OUT_TOK_LINKS                // %l %links
+	OUT_TOK_META                 // %m %meta
+)
+
+// TODO: change interface to use byte slices
+type Outputer interface {
+	OutputOne(doc index.Document) (string, error)
+	Output(docs []index.Document) (string, error)
+}
+
+type JsonOutput struct{}
+type CustomOutput struct {
+	stringTokens   []string
+	tokens         []OutputToken
+	datetimeFormat string
+}
+
+func (o JsonOutput) OutputOne(doc index.Document) (string, error) {
+	// TODO: implement
+	return "", nil
+}
+
+func (o JsonOutput) Output(docs []index.Document) (string, error) {
+	// TODO: implement
+	return "", nil
+}
+
+func parseOutputFormat(formatStr string) ([]OutputToken, []string, error) {
+	toks := make([]OutputToken, 0, 16)
+	curTok := make([]rune, 0, 16)
+	strToks := make([]string, 0, 8)
+
+	for _, c := range formatStr {
+		if c == '%' && len(curTok) > 0 && curTok[0] != '%' {
+			strToks = append(strToks, string(curTok))
+			toks = append(toks, OUT_TOK_STR)
+			curTok = curTok[:0]
+			curTok = append(curTok, c)
+			continue
+		}
+
+		curTok = append(curTok, c)
+		if curTok[0] == '%' && len(curTok) == 2 {
+			s := string(curTok)
+			if s == "%%" {
+				strToks = append(strToks, "%")
+				toks = append(toks, OUT_TOK_STR)
+			} else if s == "%p" {
+				toks = append(toks, OUT_TOK_PATH)
+			} else if s == "%T" {
+				toks = append(toks, OUT_TOK_TITLE)
+			} else if s == "%d" {
+				toks = append(toks, OUT_TOK_DATE)
+			} else if s == "%f" {
+				toks = append(toks, OUT_TOK_FILETIME)
+			} else if s == "%a" {
+				toks = append(toks, OUT_TOK_AUTHORS)
+			} else if s == "%t" {
+				toks = append(toks, OUT_TOK_TAGS)
+			} else if s == "%l" {
+				toks = append(toks, OUT_TOK_LINKS)
+			} else if s == "%m" {
+				toks = append(toks, OUT_TOK_META)
+			} else {
+				return nil, nil, ErrUnrecognizedOutputToken
+			}
+			curTok = curTok[:0]
+		}
+	}
+
+	if len(curTok) != 0 && curTok[len(curTok)-1] == '%' {
+		fmt.Println("2")
+		return nil, nil, ErrUnrecognizedOutputToken
+	} else if len(curTok) != 0 {
+		strToks = append(strToks, string(curTok))
+		toks = append(toks, OUT_TOK_STR)
+	}
+
+	return toks, strToks, nil
+}
+
+func NewCustomOutput(formatStr string, datetimeFormat string) (CustomOutput, error) {
+	outToks, strToks, err := parseOutputFormat(formatStr)
+	if err != nil {
+		return CustomOutput{}, err
+	}
+
+	return CustomOutput{strToks, outToks, datetimeFormat}, nil
+}
+
+func (o CustomOutput) OutputOne(doc index.Document) (string, error) {
+	b := strings.Builder{}
+	// TODO: determine realistic initial capacity
+
+	if err := o.writeDoc(&b, doc); err != nil {
+		return "", err
+	}
+
+	return b.String(), nil
+}
+
+func (o CustomOutput) Output(docs []index.Document) (string, error) {
+	b := strings.Builder{}
+	// TODO: determine realistic initial capacity
+
+	for i := range len(docs) - 1 {
+		if err := o.writeDoc(&b, docs[i]); err != nil {
+			return "", err
+		}
+		b.WriteRune('\n')
+	}
+	if err := o.writeDoc(&b, docs[len(docs)-1]); err != nil {
+		return "", err
+	}
+	b.WriteRune('\n')
+
+	return b.String(), nil
+}
+
+func (o CustomOutput) writeDoc(b *strings.Builder, doc index.Document) error {
+	curStrTok := 0
+	for _, token := range o.tokens {
+		if token == OUT_TOK_STR {
+			if curStrTok >= len(o.stringTokens) {
+				return ErrExpectedMoreStringTokens
+			}
+			b.WriteString(o.stringTokens[curStrTok])
+			curStrTok++
+		} else if token == OUT_TOK_PATH {
+			b.WriteString(doc.Path)
+		} else if token == OUT_TOK_TITLE {
+			b.WriteString(doc.Title)
+		} else if token == OUT_TOK_DATE {
+			b.WriteString(doc.Date.Format(o.datetimeFormat))
+		} else if token == OUT_TOK_FILETIME {
+			b.WriteString(doc.FileTime.Format(o.datetimeFormat))
+		} else if token == OUT_TOK_AUTHORS {
+			b.WriteString(strings.Join(doc.Authors, ", "))
+		} else if token == OUT_TOK_TAGS {
+			b.WriteString(strings.Join(doc.Tags, ", "))
+		} else if token == OUT_TOK_LINKS {
+			b.WriteString(strings.Join(doc.Links, ", "))
+		} else if token == OUT_TOK_META {
+			b.WriteString(doc.OtherMeta)
+		} else {
+			return ErrUnrecognizedOutputToken
+		}
+	}
+	return nil
+}