Add formatted JSON modes to the expanded reader

CHANGELOG.md

@@ -5,6 +5,19 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+- Expanded reader content modes with `raw` and `json pretty` views for long cell values
+- `F` in the expanded reader to cycle available content modes
+
+### Changed
+- Expanded reader now auto-detects valid JSON object/array strings and opens them in formatted JSON mode by default
+
+### Fixed
+- Expanded reader now refreshes content mode correctly when moving across rows, including paged row moves
+- Expanded reader caches formatted render data so large JSON cells do not re-run formatting and highlighting on every render pass
+
 ## [1.4.0] - 2026-03-24
 
 ### Added

README.md

@@ -17,7 +17,7 @@ Key features:
 - predicate filtering 
 - visual indication of missing data in rows and columns, jump to next missing value
 - missing definition can toggle between NULL+NaN, NULL, NaN 
-- adaptive column width controls with an expanded reader for long text columns
+- adaptive column width controls with an expanded reader for long text columns and structured JSON payloads
 - resize panels with the mouse
 - fast mouse scrolling
 
@@ -220,13 +220,21 @@ Predicate notes:
 
 Use this overlay for long text cells, JSON payloads, and other values that do not fit comfortably in the table.
 
+The reader supports two content modes:
+
+- `raw` for the sanitized original cell text
+- `json pretty` for valid JSON object/array strings, with formatted indentation and light semantic color
+
+When a string cell contains valid JSON object/array text, the reader opens in `json pretty` mode by default. Otherwise it opens in `raw`.
+
 | Key | Action |
 | --- | --- |
 | `Up`, `k` | Scroll up |
 | `Down`, `j` | Scroll down |
 | `Left`, `h` | Pan left when wrap is off |
 | `Right`, `l` | Pan right when wrap is off |
 | `n`, `p` | Move to next/previous row in the same column |
+| `F` | Cycle reader format (`raw` / `json pretty` when available) |
 | `W` | Toggle wrap |
 | `Space`, `Ctrl+F` | Page down |
 | `Ctrl+B` | Page up |
@@ -236,6 +244,12 @@ Use this overlay for long text cells, JSON payloads, and other values that do no
 | `G` | Jump to bottom of current cell |
 | `Esc`, `q`, `w` | Close expanded reader |
 
+Notes:
+
+- `json pretty` is available only for valid JSON object/array strings; scalar JSON values stay in `raw`.
+- Pretty JSON defaults to wrap off so indentation and horizontal panning stay readable.
+- If you move rows with `n` or `p`, the reader keeps the current mode when the next row supports it and falls back to `raw` otherwise.
+
 ### File Picker Overlay
 
 | Key | Action |

internal/ui/model.go

@@ -180,6 +180,13 @@ type Model struct {
 	detailCol       string // column shown in detail panel
 	detailTab       int    // 0=TopValues, 1=Stats, 2=Histogram
 	readerCol       string
+	readerModes     []readerMode
+	readerMode      readerMode
+	readerRender    readerRenderData
+	readerRenderFor string
+	readerRenderOK  bool
+	readerRenderW   int
+	readerRenderM   readerMode
 	readerAbsRow    int
 	readerWrap      bool
 	readerVertOff   int
@@ -316,6 +323,13 @@ func (m *Model) resetLoadedDataState() {
 	m.detailCol = ""
 	m.detailTab = 0
 	m.readerCol = ""
+	m.readerModes = nil
+	m.readerMode = readerModeRaw
+	m.readerRender = readerRenderData{}
+	m.readerRenderFor = ""
+	m.readerRenderOK = false
+	m.readerRenderW = 0
+	m.readerRenderM = readerModeRaw
 	m.readerAbsRow = 0
 	m.readerWrap = false
 	m.readerVertOff = 0
@@ -1000,6 +1014,9 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			m.clampTableRowCursor()
 			if m.overlay == OverlayCellReader {
 				m.readerAbsRow = m.tableOffset + m.tableRowCursor
+				if m.refreshReaderModes() {
+					m.statusMsg = "Reader format unavailable for this row; using raw"
+				}
 				m.clampReaderOffsets()
 			}
 			if m.needsMorePreviewRows() {
@@ -2418,7 +2435,10 @@ func (m *Model) openCellReader(colName, value string) {
 	m.overlay = OverlayCellReader
 	m.readerCol = colName
 	m.readerAbsRow = m.currentAbsoluteRow()
-	m.readerWrap = defaultReaderWrap(value)
+	m.readerModes = readerModesForValue(value)
+	m.readerMode = defaultReaderMode(m.readerModes)
+	m.invalidateReaderRenderData()
+	m.readerWrap = defaultReaderWrapForMode(m.readerMode, value)
 	m.readerVertOff = 0
 	m.readerHorizOff = 0
 	m.statusMsg = fmt.Sprintf("Opened expanded reader for %q", colName)
@@ -2427,11 +2447,65 @@ func (m *Model) openCellReader(colName, value string) {
 func (m *Model) closeCellReader() {
 	m.overlay = OverlayNone
 	m.readerCol = ""
+	m.readerModes = nil
+	m.readerMode = readerModeRaw
+	m.invalidateReaderRenderData()
 	m.readerAbsRow = 0
 	m.readerVertOff = 0
 	m.readerHorizOff = 0
 }
 
+func (m *Model) invalidateReaderRenderData() {
+	m.readerRender = readerRenderData{}
+	m.readerRenderFor = ""
+	m.readerRenderOK = false
+	m.readerRenderW = 0
+	m.readerRenderM = readerModeRaw
+}
+
+func (m *Model) refreshReaderModes() bool {
+	value, ok := m.readerCurrentValue()
+	prevMode := m.readerMode
+	prevModes := m.readerModes
+	m.readerModes = []readerMode{readerModeRaw}
+	m.readerMode = readerModeRaw
+	if !ok {
+		m.invalidateReaderRenderData()
+		return false
+	}
+
+	m.readerModes = readerModesForValue(value)
+	if slices.Contains(m.readerModes, prevMode) {
+		m.readerMode = prevMode
+		if !slices.Equal(prevModes, m.readerModes) {
+			m.invalidateReaderRenderData()
+		}
+		return false
+	}
+
+	m.readerMode = defaultReaderMode(m.readerModes)
+	if prevMode != m.readerMode || !slices.Equal(prevModes, m.readerModes) {
+		m.invalidateReaderRenderData()
+	}
+	return prevMode != readerModeRaw && m.readerMode == readerModeRaw
+}
+
+func (m *Model) cycleReaderMode() {
+	if len(m.readerModes) <= 1 {
+		m.statusMsg = "No alternate reader format"
+		return
+	}
+
+	idx := slices.Index(m.readerModes, m.readerMode)
+	if idx < 0 {
+		idx = 0
+	}
+	m.readerMode = m.readerModes[(idx+1)%len(m.readerModes)]
+	m.invalidateReaderRenderData()
+	m.clampReaderOffsets()
+	m.statusMsg = fmt.Sprintf("Reader mode: %s", m.readerMode.label())
+}
+
 // handleActiveColumnWidthAction keeps lowercase `w` adaptive: it toggles fit-width
 // for ordinary values, but opens the expanded reader when the visible column sample
 // indicates that widening would be a poor fit for the table layout.
@@ -2750,22 +2824,29 @@ func (m Model) readerCurrentValue() (string, bool) {
 	return m.valueForAbsoluteCell(m.readerAbsRow, colName)
 }
 
-func (m Model) readerRenderedLines(bodyW int) []string {
+func (m *Model) ensureReaderRenderData() readerRenderData {
 	value, ok := m.readerCurrentValue()
 	if !ok {
-		return []string{""}
+		m.invalidateReaderRenderData()
+		return readerRenderData{}
 	}
-	logical := sanitizeMultilineLogicalLines(value)
-
-	// Future: swap in structured renderers here (JSON pretty-format/highlight,
-	// Markdown, lists, key-value views) once the expanded reader supports them.
-	if m.readerWrap {
-		return wrapLogicalLines(logical, bodyW)
+	if m.readerRenderOK && m.readerRenderFor == value && m.readerRenderM == m.readerMode {
+		return m.readerRender
 	}
-	return sliceLogicalLines(logical, m.readerHorizOff, bodyW)
+
+	m.readerRender = newReaderRenderData(value, m.readerMode)
+	m.readerRenderFor = value
+	m.readerRenderOK = true
+	m.readerRenderW = m.readerRender.maxLineWidth()
+	m.readerRenderM = m.readerMode
+	return m.readerRender
 }
 
-func (m Model) maxReaderVerticalOffset() int {
+func (m *Model) readerRenderedLines(bodyW int) []string {
+	return m.ensureReaderRenderData().renderedLines(bodyW, m.readerWrap, m.readerHorizOff)
+}
+
+func (m *Model) maxReaderVerticalOffset() int {
 	innerW, _ := m.readerInnerDimensions()
 	lines := m.readerRenderedLines(innerW)
 	maxOff := len(lines) - m.readerBodyHeight()
@@ -2775,22 +2856,15 @@ func (m Model) maxReaderVerticalOffset() int {
 	return maxOff
 }
 
-func (m Model) maxReaderHorizontalOffset() int {
+func (m *Model) maxReaderHorizontalOffset() int {
 	if m.readerWrap {
 		return 0
 	}
 	innerW, _ := m.readerInnerDimensions()
-	value, ok := m.readerCurrentValue()
-	if !ok {
+	if !m.ensureReaderRenderData().hasContent() {
 		return 0
 	}
-	maxLineW := 0
-	for _, line := range sanitizeMultilineLogicalLines(value) {
-		if w := lipgloss.Width(line); w > maxLineW {
-			maxLineW = w
-		}
-	}
-	maxOff := maxLineW - innerW
+	maxOff := m.readerRenderW - innerW
 	if maxOff < 0 {
 		return 0
 	}
@@ -2862,9 +2936,9 @@ func (m *Model) toggleReaderWrap() {
 	m.readerWrap = !m.readerWrap
 	m.clampReaderOffsets()
 	if m.readerWrap {
-		m.statusMsg = "Reader wrap on"
+		m.statusMsg = fmt.Sprintf("Reader wrap on (%s)", m.readerMode.label())
 	} else {
-		m.statusMsg = "Reader wrap off"
+		m.statusMsg = fmt.Sprintf("Reader wrap off (%s)", m.readerMode.label())
 	}
 }
 
@@ -2896,6 +2970,9 @@ func (m Model) moveReaderRow(delta int) (tea.Model, tea.Cmd) {
 			}
 			m.tableOffset++
 			m.readerAbsRow = m.currentAbsoluteRow()
+			if m.refreshReaderModes() {
+				m.statusMsg = "Reader format unavailable for this row; using raw"
+			}
 			m.clampReaderOffsets()
 			return m, m.nextPreviewCmd()
 		}
@@ -2909,12 +2986,18 @@ func (m Model) moveReaderRow(delta int) (tea.Model, tea.Cmd) {
 			}
 			m.tableOffset--
 			m.readerAbsRow = m.currentAbsoluteRow()
+			if m.refreshReaderModes() {
+				m.statusMsg = "Reader format unavailable for this row; using raw"
+			}
 			m.clampReaderOffsets()
 			return m, m.nextPreviewCmd()
 		}
 	}
 
 	m.readerAbsRow = m.currentAbsoluteRow()
+	if m.refreshReaderModes() {
+		m.statusMsg = "Reader format unavailable for this row; using raw"
+	}
 	m.clampReaderOffsets()
 	return m, nil
 }
@@ -2933,6 +3016,8 @@ func (m Model) handleReaderKey(key string) (tea.Model, tea.Cmd) {
 		m.scrollReaderHoriz(1)
 	case "W":
 		m.toggleReaderWrap()
+	case "F":
+		m.cycleReaderMode()
 	case "n":
 		return m.moveReaderRow(1)
 	case "p":
@@ -3397,7 +3482,7 @@ func (m Model) viewBottomBar() string {
 	var hints string
 	switch {
 	case m.overlay == OverlayCellReader:
-		hints = "w/Esc:close  ↑↓/jk:scroll  ←→/hl:pan  W:wrap  n/p:row  Space/C-f/C-b:page  C-d/u:half  g/G:top/bottom"
+		hints = "w/Esc:close  ↑↓/jk:scroll  ←→/hl:pan  W:wrap  F:format/raw  n/p:row  Space/C-f/C-b:page  C-d/u:half  g/G:top/bottom"
 	case m.focus == FocusColumns:
 		hints = "Ctrl+O:open  jk/↑↓:move  Space/C-f/C-b:page  C-d/u:half  gG/HML:jump  m:missing-mode  /:search  v:sel-list  x:toggle  a/d/y:sel"
 	default:
@@ -3456,13 +3541,15 @@ func (m Model) viewCellReader(w, h int) string {
 	if colType != "" {
 		header += "  " + colType
 	}
+	header = readerHeaderStyle.Render(header)
+	header = lipgloss.JoinHorizontal(lipgloss.Left, header, " ", readerModeBadge(m.readerMode))
 	if m.readerWrap {
-		header += "  wrap:on"
+		header = lipgloss.JoinHorizontal(lipgloss.Left, header, readerHeaderStyle.Render("  wrap:on"))
 	} else {
-		header += "  wrap:off"
+		header = lipgloss.JoinHorizontal(lipgloss.Left, header, readerHeaderStyle.Render("  wrap:off"))
 	}
-	header += fmt.Sprintf("  len:%d", utf8.RuneCountInString(value))
-	header = clampLineWidth(readerHeaderStyle.Render(header), w)
+	header = lipgloss.JoinHorizontal(lipgloss.Left, header, readerHeaderStyle.Render(fmt.Sprintf("  len:%d", utf8.RuneCountInString(value))))
+	header = clampLineWidth(header, w)
 
 	topEdge := readerEdgeStyle.Width(w).Render(strings.Repeat("─", max(1, w)))
 	if m.readerVertOff == 0 {
@@ -3487,13 +3574,13 @@ func (m Model) viewCellReader(w, h int) string {
 
 	bodyLines := make([]string, 0, bodyH)
 	for _, line := range lines[start:end] {
-		bodyLines = append(bodyLines, clampLineWidth(readerBodyStyle.Render(padDisplayRight(line, w)), w))
+		bodyLines = append(bodyLines, padReaderLine(line, w, m.readerMode))
 	}
 	for len(bodyLines) < bodyH {
 		bodyLines = append(bodyLines, readerBodyStyle.Render(strings.Repeat(" ", w)))
 	}
 
-	footer := " Scroll: ↑↓/jk  Row: n/p  Wrap: W  Page: Space/C-f/C-b  Close: Esc/w"
+	footer := " Scroll: ↑↓/jk  Row: n/p  Wrap: W  F:format/raw  Page: Space/C-f/C-b  Close: Esc/w"
 	footer = clampLineWidth(readerFooterStyle.Render(footer), w)
 
 	return strings.Join(append([]string{header, topEdge}, append(bodyLines, bottomEdge, footer)...), "\n")
@@ -4084,6 +4171,7 @@ func (m Model) viewHelp() string {
 		{"↑/↓ or j/k", "Scroll content"},
 		{"←/→ or h/l", "Pan horizontally (wrap off)"},
 		{"n / p", "Next / previous row in same column"},
+		{"F", "Cycle reader format"},
 		{"W", "Toggle wrap"},
 		{"Ctrl+F / Space", "Page down"},
 		{"Ctrl+B", "Page up"},