shitty hack for terrible charm bubbletea performance

packages/tui/internal/viewport/highlight.go

@@ -0,0 +1,141 @@
+package viewport
+
+import (
+	"github.com/charmbracelet/lipgloss/v2"
+	"github.com/charmbracelet/x/ansi"
+	"github.com/rivo/uniseg"
+)
+
+// parseMatches converts the given matches into highlight ranges.
+//
+// Assumptions:
+// - matches are measured in bytes, e.g. what [regex.FindAllStringIndex] would return
+// - matches were made against the given content
+// - matches are in order
+// - matches do not overlap
+// - content is line terminated with \n only
+//
+// We'll then convert the ranges into [highlightInfo]s, which hold the starting
+// line and the grapheme positions.
+func parseMatches(
+	content string,
+	matches [][]int,
+) []highlightInfo {
+	if len(matches) == 0 {
+		return nil
+	}
+
+	line := 0
+	graphemePos := 0
+	previousLinesOffset := 0
+	bytePos := 0
+
+	highlights := make([]highlightInfo, 0, len(matches))
+	gr := uniseg.NewGraphemes(ansi.Strip(content))
+
+	for _, match := range matches {
+		byteStart, byteEnd := match[0], match[1]
+
+		// hilight for this match:
+		hi := highlightInfo{
+			lines: map[int][2]int{},
+		}
+
+		// find the beginning of this byte range, setup current line and
+		// grapheme position.
+		for byteStart > bytePos {
+			if !gr.Next() {
+				break
+			}
+			if content[bytePos] == '\n' {
+				previousLinesOffset = graphemePos + 1
+				line++
+			}
+			graphemePos += max(1, gr.Width())
+			bytePos += len(gr.Str())
+		}
+
+		hi.lineStart = line
+		hi.lineEnd = line
+
+		graphemeStart := graphemePos
+
+		// loop until we find the end
+		for byteEnd > bytePos {
+			if !gr.Next() {
+				break
+			}
+
+			// if it ends with a new line, add the range, increase line, and continue
+			if content[bytePos] == '\n' {
+				colstart := max(0, graphemeStart-previousLinesOffset)
+				colend := max(graphemePos-previousLinesOffset+1, colstart) // +1 its \n itself
+
+				if colend > colstart {
+					hi.lines[line] = [2]int{colstart, colend}
+					hi.lineEnd = line
+				}
+
+				previousLinesOffset = graphemePos + 1
+				line++
+			}
+
+			graphemePos += max(1, gr.Width())
+			bytePos += len(gr.Str())
+		}
+
+		// we found it!, add highlight and continue
+		if bytePos == byteEnd {
+			colstart := max(0, graphemeStart-previousLinesOffset)
+			colend := max(graphemePos-previousLinesOffset, colstart)
+
+			if colend > colstart {
+				hi.lines[line] = [2]int{colstart, colend}
+				hi.lineEnd = line
+			}
+		}
+
+		highlights = append(highlights, hi)
+	}
+
+	return highlights
+}
+
+type highlightInfo struct {
+	// in which line this highlight starts and ends
+	lineStart, lineEnd int
+
+	// the grapheme highlight ranges for each of these lines
+	lines map[int][2]int
+}
+
+// coords returns the line x column of this highlight.
+func (hi highlightInfo) coords() (int, int, int) {
+	for i := hi.lineStart; i <= hi.lineEnd; i++ {
+		hl, ok := hi.lines[i]
+		if !ok {
+			continue
+		}
+		return i, hl[0], hl[1]
+	}
+	return hi.lineStart, 0, 0
+}
+
+func makeHighlightRanges(
+	highlights []highlightInfo,
+	line int,
+	style lipgloss.Style,
+) []lipgloss.Range {
+	result := []lipgloss.Range{}
+	for _, hi := range highlights {
+		lihi, ok := hi.lines[line]
+		if !ok {
+			continue
+		}
+		if lihi == [2]int{} {
+			continue
+		}
+		result = append(result, lipgloss.NewRange(lihi[0], lihi[1], style))
+	}
+	return result
+}