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package editor
import (
"regexp"
"strings"
"glint/internal/theme"
"github.com/charmbracelet/lipgloss"
)
var (
headingRe = regexp.MustCompile(`^\s*#{1,6}\s`)
listRe = regexp.MustCompile(`^\s*([-*+]|\d+\.)\s`)
)
// blockState carries cross-line context (fenced code, leading frontmatter).
type blockState struct {
inFence bool
inFrontmatter bool
frontmatterDone bool
}
// ScanLines styles every line, threading block state across lines. The returned
// slice is parallel to the input: out[i] are the spans for lines[i], whose
// concatenated text equals lines[i] exactly.
func ScanLines(lines []string, th theme.Theme) [][]Span {
st := &blockState{}
out := make([][]Span, len(lines))
for i, ln := range lines {
out[i] = scanLine(i, ln, st, th)
}
return out
}
func scanLine(row int, line string, st *blockState, th theme.Theme) []Span {
code := lipgloss.NewStyle().Foreground(th.Code)
muted := lipgloss.NewStyle().Foreground(th.Blockquote)
trimmed := strings.TrimSpace(line)
// Fenced code block: body lines are entirely code-colored.
if st.inFence {
if strings.HasPrefix(trimmed, "```") {
st.inFence = false
}
return wholeLine(line, code)
}
if strings.HasPrefix(trimmed, "```") {
st.inFence = true
return wholeLine(line, code)
}
// Leading YAML frontmatter: only valid starting at row 0.
if st.inFrontmatter {
if trimmed == "---" {
st.inFrontmatter = false
st.frontmatterDone = true
return wholeLine(line, muted)
}
return scanFrontmatter(line, th)
}
if row == 0 && trimmed == "---" {
st.inFrontmatter = true
return wholeLine(line, muted)
}
// Heading: color the whole line, hashes included.
if headingRe.MatchString(line) {
return wholeLine(line, lipgloss.NewStyle().Foreground(th.Heading).Bold(true))
}
// Blockquote.
if strings.HasPrefix(trimmed, ">") {
return wholeLine(line, muted)
}
// List marker, then inline-scan the remainder.
if loc := listRe.FindStringIndex(line); loc != nil {
marker := line[:loc[1]]
rest := line[loc[1]:]
spans := []Span{{Text: marker, Style: lipgloss.NewStyle().Foreground(th.ListMarker)}}
return append(spans, scanInline(rest, th)...)
}
return scanInline(line, th)
}
// wholeLine returns a single span for the whole line, or no spans if empty.
func wholeLine(line string, style lipgloss.Style) []Span {
if line == "" {
return nil
}
return []Span{{Text: line, Style: style}}
}
// scanFrontmatter highlights one YAML frontmatter line, keeping every character
// visible: the spans concatenate back to the raw line exactly.
// - "# comment" -> whole line muted
// - " - item" -> leading ws + dash (ListMarker) + item (Text)
// - "key: value" -> "key:" (Accent) + " value" (Text)
// - anything else -> whole line Text
func scanFrontmatter(line string, th theme.Theme) []Span {
muted := lipgloss.NewStyle().Foreground(th.Blockquote)
accent := lipgloss.NewStyle().Foreground(th.Accent)
plain := lipgloss.NewStyle().Foreground(th.Text)
marker := lipgloss.NewStyle().Foreground(th.ListMarker)
trimmed := strings.TrimSpace(line)
// Comment line.
if strings.HasPrefix(trimmed, "#") {
return wholeLine(line, muted)
}
// List item: optional leading whitespace, then "- ...".
if loc := listRe.FindStringIndex(line); loc != nil && strings.HasPrefix(trimmed, "-") {
mk := line[:loc[1]] // leading ws + "- "
rest := line[loc[1]:] // item text
spans := []Span{{Text: mk, Style: marker}}
if rest != "" {
spans = append(spans, Span{Text: rest, Style: plain})
}
return spans
}
// key: value — split at the first colon. Keep the colon with the key.
if idx := strings.IndexByte(line, ':'); idx >= 0 {
key := line[:idx+1] // includes the colon
rest := line[idx+1:] // remainder (may start with a space)
spans := []Span{{Text: key, Style: accent}}
if rest != "" {
spans = append(spans, Span{Text: rest, Style: plain})
}
return spans
}
// Bare line (e.g. a continuation): plain text.
return wholeLine(line, plain)
}
// scanInline emits styled spans for inline constructs, keeping all markup
// characters visible. Plain text gets the theme's Text foreground.
func scanInline(text string, th theme.Theme) []Span {
plain := lipgloss.NewStyle().Foreground(th.Text)
r := []rune(text)
var spans []Span
start, i := 0, 0
flush := func(end int) {
if end > start {
spans = append(spans, Span{Text: string(r[start:end]), Style: plain})
}
}
for i < len(r) {
if tok, style, n, ok := matchToken(r, i, th); ok {
flush(i)
spans = append(spans, Span{Text: tok, Style: style})
i += n
start = i
continue
}
i++
}
flush(len(r))
return spans
}
// matchToken tries to match an inline construct starting at r[i]. It returns the
// token (including its markup), the style, the rune length, and whether matched.
func matchToken(r []rune, i int, th theme.Theme) (string, lipgloss.Style, int, bool) {
// Inline code: `...`
if r[i] == '`' {
if j := indexRune(r, '`', i+1); j > i {
return string(r[i : j+1]), lipgloss.NewStyle().Foreground(th.Code), j + 1 - i, true
}
}
// Wikilink: [[...]]
if r[i] == '[' && i+1 < len(r) && r[i+1] == '[' {
if j := indexSeq(r, "]]", i+2); j >= 0 {
end := j + 2
return string(r[i:end]), lipgloss.NewStyle().Foreground(th.Wikilink), end - i, true
}
}
// Link: [text](url)
if r[i] == '[' {
if c := indexRune(r, ']', i+1); c > i && c+1 < len(r) && r[c+1] == '(' {
if p := indexRune(r, ')', c+2); p > c {
end := p + 1
return string(r[i:end]), lipgloss.NewStyle().Foreground(th.Link), end - i, true
}
}
}
// Bold: ** or __
for _, d := range []string{"**", "__"} {
if hasPrefixRunes(r, i, d) {
if j := indexSeq(r, d, i+2); j >= 0 {
end := j + 2
return string(r[i:end]), lipgloss.NewStyle().Foreground(th.Text).Bold(true), end - i, true
}
}
}
// Italic: * or _
if r[i] == '*' || r[i] == '_' {
if j := indexRune(r, r[i], i+1); j > i {
end := j + 1
return string(r[i:end]), lipgloss.NewStyle().Foreground(th.Text).Italic(true), end - i, true
}
}
return "", lipgloss.Style{}, 0, false
}
func indexRune(r []rune, c rune, from int) int {
for i := from; i < len(r); i++ {
if r[i] == c {
return i
}
}
return -1
}
func indexSeq(r []rune, seq string, from int) int {
s := []rune(seq)
for i := from; i+len(s) <= len(r); i++ {
match := true
for k := range s {
if r[i+k] != s[k] {
match = false
break
}
}
if match {
return i
}
}
return -1
}
func hasPrefixRunes(r []rune, i int, prefix string) bool {
p := []rune(prefix)
if i+len(p) > len(r) {
return false
}
for k := range p {
if r[i+k] != p[k] {
return false
}
}
return true
}
|