handle context blocks and better error reporting

internal/chunk/file.go

@@ -8,7 +8,6 @@ import (
 	"io"
 	"log"
 	"path/filepath"
-	"runtime"
 	"runtime/trace"
 	"sort"
 	"strings"
@@ -126,24 +125,16 @@ func indexChunks(dec decoder) (index, error) {
 		idx[id] = append(idx[id], offset)
 	}
 
-	logger.Default.Debugf("indexing chunks: %d: called from %v, took %s (%.2f/sec)", len(idx), caller(2), time.Since(start), float64(len(idx))/time.Since(start).Seconds())
+	logger.Default.Debugf("indexing chunks: %d: called from %v, took %s (%.2f/sec)", len(idx), osext.Caller(2), time.Since(start), float64(len(idx))/time.Since(start).Seconds())
 	return idx, nil
 }
 
-func caller(steps int) string {
-	name := "?"
-	if pc, _, _, ok := runtime.Caller(steps + 1); ok {
-		name = filepath.Base(runtime.FuncForPC(pc).Name())
-	}
-	return name
-}
-
 // ensure ensures that the file index was generated.
 //
 // TODO: maybe it shouldn't panic.
 func (f *File) ensure() {
 	if f.idx == nil {
-		log.Panicf("internal error:  %s called before File.Open", caller(1))
+		log.Panicf("internal error:  %s called before File.Open", osext.Caller(1))
 	}
 }
 

internal/osext/caller.go

@@ -0,0 +1,14 @@
+package osext
+
+import (
+	"path/filepath"
+	"runtime"
+)
+
+func Caller(steps int) string {
+	name := "?"
+	if pc, _, _, ok := runtime.Caller(steps + 1); ok {
+		name = filepath.Base(runtime.FuncForPC(pc).Name())
+	}
+	return name
+}

internal/viewer/renderer/slack.go

@@ -2,14 +2,15 @@ package renderer
 
 import (
 	"encoding/json"
-	"errors"
+	"fmt"
 	"html"
 	"html/template"
 	"log/slog"
 	"os"
 	"strings"
 
 	"github.com/rusq/slack"
+	"github.com/rusq/slackdump/v3/internal/osext"
 )
 
 const debug = true
@@ -62,5 +63,38 @@ var blockAction = map[slack.MessageBlockType]func(slack.Block) (string, error){
 	slack.MBTContext:  mbtContext,
 }
 
-// ErrIncorrectBlockType is returned when the block type is not handled.
-var ErrIncorrectBlockType = errors.New("incorrect block type")
+const stackframe = 1
+
+type ErrIncorrectBlockType struct {
+	Caller string
+	Want   any
+	Got    any
+}
+
+func (e *ErrIncorrectBlockType) Error() string {
+	return fmt.Sprintf("incorrect block type for block %s: want %T, got %T", e.Caller, e.Want, e.Got)
+}
+
+func NewErrIncorrectType(want, got any) error {
+	return &ErrIncorrectBlockType{
+		Caller: osext.Caller(stackframe),
+		Want:   want,
+		Got:    got,
+	}
+}
+
+type ErrMissingHandler struct {
+	Caller string
+	Type   any
+}
+
+func (e *ErrMissingHandler) Error() string {
+	return fmt.Sprintf("missing handler for type %v called in %s", e.Type, e.Caller)
+}
+
+func NewErrMissingHandler(t any) error {
+	return &ErrMissingHandler{
+		Caller: osext.Caller(stackframe),
+		Type:   t,
+	}
+}

internal/viewer/renderer/slack_context.go

@@ -10,13 +10,13 @@ import (
 func mbtContext(ib slack.Block) (string, error) {
 	b, ok := ib.(*slack.ContextBlock)
 	if !ok {
-		return "", ErrIncorrectBlockType
+		return "", NewErrIncorrectType(&slack.ContextBlock{}, ib)
 	}
 	var buf strings.Builder
 	for _, el := range b.ContextElements.Elements {
 		fn, ok := contextElementHandlers[el.MixedElementType()]
 		if !ok {
-			return "", ErrIncorrectBlockType
+			return "", NewErrMissingHandler(el.MixedElementType())
 		}
 		s, err := fn(el)
 		if err != nil {
@@ -30,12 +30,21 @@ func mbtContext(ib slack.Block) (string, error) {
 
 var contextElementHandlers = map[slack.MixedElementType]func(slack.MixedElement) (string, error){
 	slack.MixedElementImage: metImage,
+	slack.MixedElementText:  metText,
 }
 
 func metImage(ie slack.MixedElement) (string, error) {
 	e, ok := ie.(*slack.ImageBlockElement)
 	if !ok {
-		return "", ErrIncorrectBlockType
+		return "", NewErrIncorrectType(&slack.ImageBlockElement{}, ie)
 	}
 	return fmt.Sprintf(`<img src="%s" alt="%s">`, e.ImageURL, e.AltText), nil
 }
+
+func metText(ie slack.MixedElement) (string, error) {
+	e, ok := ie.(*slack.TextBlockObject)
+	if !ok {
+		return "", NewErrIncorrectType(&slack.TextBlockObject{}, ie)
+	}
+	return e.Text, nil
+}

internal/viewer/renderer/slack_image.go

@@ -9,7 +9,7 @@ import (
 func mbtImage(ib slack.Block) (string, error) {
 	b, ok := ib.(*slack.ImageBlock)
 	if !ok {
-		return "", ErrIncorrectBlockType
+		return "", NewErrIncorrectType(&slack.ImageBlock{}, ib)
 	}
 	return fmt.Sprintf(`<img src="%s" alt="%s">`, b.ImageURL, b.AltText), nil
 }

internal/viewer/renderer/slack_rich_text.go

@@ -19,13 +19,13 @@ func init() {
 func mbtRichText(ib slack.Block) (string, error) {
 	b, ok := ib.(*slack.RichTextBlock)
 	if !ok {
-		return "", ErrIncorrectBlockType
+		return "", NewErrIncorrectType(&slack.RichTextBlock{}, ib)
 	}
 	var buf strings.Builder
 	for _, el := range b.Elements {
 		fn, ok := rteTypeHandlers[el.RichTextElementType()]
 		if !ok {
-			return "", ErrIncorrectBlockType
+			return "", NewErrMissingHandler(el.RichTextElementType())
 		}
 		s, err := fn(el)
 		if err != nil {
@@ -40,13 +40,13 @@ func mbtRichText(ib slack.Block) (string, error) {
 func rteSection(ie slack.RichTextElement) (string, error) {
 	e, ok := ie.(*slack.RichTextSection)
 	if !ok {
-		return "", ErrIncorrectBlockType
+		return "", NewErrIncorrectType(&slack.RichTextSection{}, ie)
 	}
 	var buf strings.Builder
 	for _, el := range e.Elements {
 		fn, ok := rtseHandlers[el.RichTextSectionElementType()]
 		if !ok {
-			return "", ErrIncorrectBlockType
+			return "", NewErrMissingHandler(el.RichTextSectionElementType())
 		}
 		s, err := fn(el)
 		if err != nil {
@@ -69,7 +69,7 @@ var rtseHandlers = map[slack.RichTextSectionElementType]func(slack.RichTextSecti
 func rtseText(ie slack.RichTextSectionElement) (string, error) {
 	e, ok := ie.(*slack.RichTextSectionTextElement)
 	if !ok {
-		return "", fmt.Errorf("%T: %w", ie, ErrIncorrectBlockType)
+		return "", NewErrIncorrectType(&slack.RichTextSectionTextElement{}, ie)
 	}
 	var t = strings.Replace(e.Text, "\n", "<br>", -1)
 
@@ -98,7 +98,7 @@ func applyStyle(s string, style *slack.RichTextSectionTextStyle) string {
 func rtseLink(ie slack.RichTextSectionElement) (string, error) {
 	e, ok := ie.(*slack.RichTextSectionLinkElement)
 	if !ok {
-		return "", fmt.Errorf("%T: %w", ie, ErrIncorrectBlockType)
+		return "", NewErrIncorrectType(&slack.RichTextSectionLinkElement{}, ie)
 	}
 	if e.Text == "" {
 		e.Text = e.URL
@@ -109,7 +109,7 @@ func rtseLink(ie slack.RichTextSectionElement) (string, error) {
 func rteList(ie slack.RichTextElement) (string, error) {
 	e, ok := ie.(*slack.RichTextList)
 	if !ok {
-		return "", ErrIncorrectBlockType
+		return "", NewErrIncorrectType(&slack.RichTextList{}, ie)
 	}
 	// const orderedTypes = "1aAiI"
 	var tgOpen, tgClose string
@@ -126,7 +126,7 @@ func rteList(ie slack.RichTextElement) (string, error) {
 	for _, el := range e.Elements {
 		fn, ok := rteTypeHandlers[el.RichTextElementType()]
 		if !ok {
-			return "", ErrIncorrectBlockType
+			return "", NewErrMissingHandler(el.RichTextElementType())
 		}
 		s, err := fn(el)
 		if err != nil {
@@ -141,14 +141,14 @@ func rteList(ie slack.RichTextElement) (string, error) {
 func rteQuote(ie slack.RichTextElement) (string, error) {
 	e, ok := ie.(*slack.RichTextQuote)
 	if !ok {
-		return "", ErrIncorrectBlockType
+		return "", NewErrIncorrectType(&slack.RichTextQuote{}, ie)
 	}
 	var buf strings.Builder
 	buf.WriteString("<blockquote>")
 	for _, el := range e.Elements {
 		fn, ok := rtseHandlers[el.RichTextSectionElementType()]
 		if !ok {
-			return "", ErrIncorrectBlockType
+			return "", NewErrMissingHandler(el.RichTextSectionElementType())
 		}
 		s, err := fn(el)
 		if err != nil {
@@ -163,14 +163,14 @@ func rteQuote(ie slack.RichTextElement) (string, error) {
 func rtePreformatted(ie slack.RichTextElement) (string, error) {
 	e, ok := ie.(*slack.RichTextPreformatted)
 	if !ok {
-		return "", ErrIncorrectBlockType
+		return "", NewErrIncorrectType(&slack.RichTextPreformatted{}, ie)
 	}
 	var buf strings.Builder
 	buf.WriteString("<pre>")
 	for _, el := range e.Elements {
 		fn, ok := rtseHandlers[el.RichTextSectionElementType()]
 		if !ok {
-			return "", ErrIncorrectBlockType
+			return "", NewErrMissingHandler(el.RichTextSectionElementType())
 		}
 		s, err := fn(el)
 		if err != nil {
@@ -185,7 +185,7 @@ func rtePreformatted(ie slack.RichTextElement) (string, error) {
 func rtseUser(ie slack.RichTextSectionElement) (string, error) {
 	e, ok := ie.(*slack.RichTextSectionUserElement)
 	if !ok {
-		return "", fmt.Errorf("%T: %w", ie, ErrIncorrectBlockType)
+		return "", NewErrIncorrectType(&slack.RichTextSectionUserElement{}, ie)
 	}
 	// TODO: link user.
 	return applyStyle(fmt.Sprintf("<@%s>", e.UserID), e.Style), nil
@@ -194,7 +194,7 @@ func rtseUser(ie slack.RichTextSectionElement) (string, error) {
 func rtseEmoji(ie slack.RichTextSectionElement) (string, error) {
 	e, ok := ie.(*slack.RichTextSectionEmojiElement)
 	if !ok {
-		return "", fmt.Errorf("%T: %w", ie, ErrIncorrectBlockType)
+		return "", NewErrIncorrectType(&slack.RichTextSectionEmojiElement{}, ie)
 	}
 	// TODO: resolve and render emoji.
 	return applyStyle(fmt.Sprintf(":%s:", e.Name), e.Style), nil
@@ -203,7 +203,7 @@ func rtseEmoji(ie slack.RichTextSectionElement) (string, error) {
 func rtseChannel(ie slack.RichTextSectionElement) (string, error) {
 	e, ok := ie.(*slack.RichTextSectionChannelElement)
 	if !ok {
-		return "", fmt.Errorf("%T: %w", ie, ErrIncorrectBlockType)
+		return "", NewErrIncorrectType(&slack.RichTextSectionChannelElement{}, ie)
 	}
 	return applyStyle(fmt.Sprintf("<#%s>", e.ChannelID), e.Style), nil
 }