fix: latex math support

internal/ui/views.go

@@ -660,11 +660,20 @@ func renderNotesWithHighlighting(notes []string) []string {
 			} else if codeBlockDelimiter == "markdown" {
 				// Ending a markdown code block
 				inCodeBlock = false
-				// Highlight and add the code
+				// Highlight and add the code (or render LaTeX)
 				if len(codeLines) > 0 {
-					highlighted := highlightCode(strings.Join(codeLines, "\n"), codeLanguage)
-					highlightedLines := strings.Split(highlighted, "\n")
-					result = append(result, highlightedLines...)
+					var processedLines []string
+					if codeLanguage == "latex" {
+						// Apply LaTeX-to-Unicode conversion
+						for _, line := range codeLines {
+							processedLines = append(processedLines, renderLatexMath(line))
+						}
+					} else {
+						// Apply syntax highlighting
+						highlighted := highlightCode(strings.Join(codeLines, "\n"), codeLanguage)
+						processedLines = strings.Split(highlighted, "\n")
+					}
+					result = append(result, processedLines...)
 				}
 				result = append(result, note) // Keep the delimiter visible
 				codeLines = []string{}
@@ -677,11 +686,20 @@ func renderNotesWithHighlighting(notes []string) []string {
 		// Check for org-mode style code block end
 		if strings.HasPrefix(trimmed, "#+END_SRC") {
 			inCodeBlock = false
-			// Highlight and add the code
+			// Highlight and add the code (or render LaTeX)
 			if len(codeLines) > 0 {
-				highlighted := highlightCode(strings.Join(codeLines, "\n"), codeLanguage)
-				highlightedLines := strings.Split(highlighted, "\n")
-				result = append(result, highlightedLines...)
+				var processedLines []string
+				if codeLanguage == "latex" {
+					// Apply LaTeX-to-Unicode conversion
+					for _, line := range codeLines {
+						processedLines = append(processedLines, renderLatexMath(line))
+					}
+				} else {
+					// Apply syntax highlighting
+					highlighted := highlightCode(strings.Join(codeLines, "\n"), codeLanguage)
+					processedLines = strings.Split(highlighted, "\n")
+				}
+				result = append(result, processedLines...)
 			}
 			result = append(result, note) // Keep the delimiter visible
 			codeLines = []string{}
@@ -700,9 +718,18 @@ func renderNotesWithHighlighting(notes []string) []string {
 
 	// Handle case where code block wasn't closed
 	if inCodeBlock && len(codeLines) > 0 {
-		highlighted := highlightCode(strings.Join(codeLines, "\n"), codeLanguage)
-		highlightedLines := strings.Split(highlighted, "\n")
-		result = append(result, highlightedLines...)
+		var processedLines []string
+		if codeLanguage == "latex" {
+			// Apply LaTeX-to-Unicode conversion
+			for _, line := range codeLines {
+				processedLines = append(processedLines, renderLatexMath(line))
+			}
+		} else {
+			// Apply syntax highlighting
+			highlighted := highlightCode(strings.Join(codeLines, "\n"), codeLanguage)
+			processedLines = strings.Split(highlighted, "\n")
+		}
+		result = append(result, processedLines...)
 	}
 
 	return result
@@ -724,6 +751,383 @@ func highlightCode(code, language string) string {
 	return strings.TrimRight(buf.String(), "\n")
 }
 
+// renderLatexMath converts LaTeX math expressions to Unicode for terminal display
+func renderLatexMath(latex string) string {
+	result := latex
+
+	// Remove LaTeX math delimiters
+	result = strings.ReplaceAll(result, `\(`, "")
+	result = strings.ReplaceAll(result, `\)`, "")
+	result = strings.ReplaceAll(result, `\[`, "")
+	result = strings.ReplaceAll(result, `\]`, "")
+	result = strings.ReplaceAll(result, `$$`, "")
+
+	// Remove single $ delimiters (being careful not to remove actual dollar signs in text)
+	// Simple approach: if line starts/ends with $, remove it
+	result = strings.TrimSpace(result)
+	if strings.HasPrefix(result, "$") && strings.HasSuffix(result, "$") && len(result) > 2 {
+		result = result[1 : len(result)-1]
+		result = strings.TrimSpace(result)
+	}
+
+	// Map of common LaTeX commands to Unicode equivalents
+	replacements := map[string]string{
+		// Greek letters (lowercase)
+		`\alpha`:   "α",
+		`\beta`:    "β",
+		`\gamma`:   "γ",
+		`\delta`:   "δ",
+		`\epsilon`: "ε",
+		`\zeta`:    "ζ",
+		`\eta`:     "η",
+		`\theta`:   "θ",
+		`\iota`:    "ι",
+		`\kappa`:   "κ",
+		`\lambda`:  "λ",
+		`\mu`:      "μ",
+		`\nu`:      "ν",
+		`\xi`:      "ξ",
+		`\pi`:      "π",
+		`\rho`:     "ρ",
+		`\sigma`:   "σ",
+		`\tau`:     "τ",
+		`\upsilon`: "υ",
+		`\phi`:     "φ",
+		`\chi`:     "χ",
+		`\psi`:     "ψ",
+		`\omega`:   "ω",
+
+		// Greek letters (uppercase)
+		`\Gamma`:   "Γ",
+		`\Delta`:   "Δ",
+		`\Theta`:   "Θ",
+		`\Lambda`:  "Λ",
+		`\Xi`:      "Ξ",
+		`\Pi`:      "Π",
+		`\Sigma`:   "Σ",
+		`\Upsilon`: "Υ",
+		`\Phi`:     "Φ",
+		`\Psi`:     "Ψ",
+		`\Omega`:   "Ω",
+
+		// Math operators
+		`\times`:   "×",
+		`\div`:     "÷",
+		`\pm`:      "±",
+		`\mp`:      "∓",
+		`\cdot`:    "·",
+		`\star`:    "⋆",
+		`\ast`:     "∗",
+		`\circ`:    "∘",
+		`\bullet`:  "•",
+
+		// Relations
+		`\le`:      "≤",
+		`\ge`:      "≥",
+		`\leq`:     "≤",
+		`\geq`:     "≥",
+		`\ne`:      "≠",
+		`\neq`:     "≠",
+		`\approx`:  "≈",
+		`\equiv`:   "≡",
+		`\sim`:     "∼",
+		`\simeq`:   "≃",
+		`\propto`:  "∝",
+
+		// Arrows
+		`\to`:         "→",
+		`\rightarrow`: "→",
+		`\leftarrow`:  "←",
+		`\Rightarrow`: "⇒",
+		`\Leftarrow`:  "⇐",
+		`\mapsto`:     "↦",
+
+		// Set theory
+		`\in`:       "∈",
+		`\notin`:    "∉",
+		`\subset`:   "⊂",
+		`\supset`:   "⊃",
+		`\subseteq`: "⊆",
+		`\supseteq`: "⊇",
+		`\cup`:      "∪",
+		`\cap`:      "∩",
+		`\emptyset`: "∅",
+		`\forall`:   "∀",
+		`\exists`:   "∃",
+
+		// Calculus
+		`\partial`: "∂",
+		`\nabla`:   "∇",
+		`\int`:     "∫",
+		`\sum`:     "∑",
+		`\prod`:    "∏",
+		`\infty`:   "∞",
+
+		// Logic
+		`\land`:  "∧",
+		`\lor`:   "∨",
+		`\lnot`:  "¬",
+		`\neg`:   "¬",
+		`\wedge`: "∧",
+		`\vee`:   "∨",
+
+		// Special symbols
+		`\hbar`:    "ℏ",
+		`\ell`:     "ℓ",
+		`\Re`:      "ℜ",
+		`\Im`:      "ℑ",
+		`\angle`:   "∠",
+		`\triangle`: "△",
+		`\square`:  "□",
+		`\degree`:  "°",
+
+		// Superscripts (common ones)
+		`^0`: "⁰",
+		`^1`: "¹",
+		`^2`: "²",
+		`^3`: "³",
+		`^4`: "⁴",
+		`^5`: "⁵",
+		`^6`: "⁶",
+		`^7`: "⁷",
+		`^8`: "⁸",
+		`^9`: "⁹",
+		`^+`: "⁺",
+		`^-`: "⁻",
+		`^=`: "⁼",
+		`^(`: "⁽",
+		`^)`: "⁾",
+
+		// Subscripts (common ones)
+		`_0`: "₀",
+		`_1`: "₁",
+		`_2`: "₂",
+		`_3`: "₃",
+		`_4`: "₄",
+		`_5`: "₅",
+		`_6`: "₆",
+		`_7`: "₇",
+		`_8`: "₈",
+		`_9`: "₉",
+		`_+`: "₊",
+		`_-`: "₋",
+		`_=`: "₌",
+		`_(`: "₍",
+		`_)`: "₎",
+	}
+
+	// Apply all replacements
+	for latexCmd, unicode := range replacements {
+		result = strings.ReplaceAll(result, latexCmd, unicode)
+	}
+
+	// Handle simple fractions \frac{a}{b} -> a/b
+	result = handleFractions(result)
+
+	// Handle square roots \sqrt{x} -> √(x)
+	result = handleSquareRoots(result)
+
+	// Handle superscripts ^{...} and subscripts _{...}
+	result = handleSuperscripts(result)
+	result = handleSubscripts(result)
+
+	return result
+}
+
+// handleFractions converts \frac{numerator}{denominator} to numerator/denominator
+func handleFractions(text string) string {
+	// Simple regex-free approach for basic fractions
+	result := text
+	for {
+		start := strings.Index(result, `\frac{`)
+		if start == -1 {
+			break
+		}
+
+		// Find the numerator
+		numStart := start + 6
+		numEnd, numerator := findBracedContent(result, numStart)
+		if numEnd == -1 {
+			break
+		}
+
+		// Find the denominator
+		if numEnd >= len(result) || result[numEnd] != '{' {
+			break
+		}
+		denomEnd, denominator := findBracedContent(result, numEnd+1)
+		if denomEnd == -1 {
+			break
+		}
+
+		// Replace \frac{num}{denom} with (num)/(denom)
+		replacement := "(" + numerator + ")/(" + denominator + ")"
+		result = result[:start] + replacement + result[denomEnd:]
+	}
+	return result
+}
+
+// handleSquareRoots converts \sqrt{x} to √(x)
+func handleSquareRoots(text string) string {
+	result := text
+	for {
+		start := strings.Index(result, `\sqrt{`)
+		if start == -1 {
+			break
+		}
+
+		// Find the content
+		contentStart := start + 6
+		contentEnd, content := findBracedContent(result, contentStart)
+		if contentEnd == -1 {
+			break
+		}
+
+		// Replace \sqrt{content} with √(content)
+		replacement := "√(" + content + ")"
+		result = result[:start] + replacement + result[contentEnd:]
+	}
+	return result
+}
+
+// findBracedContent finds content within braces starting at position i
+// Returns the position after the closing brace and the content
+func findBracedContent(text string, start int) (int, string) {
+	if start >= len(text) {
+		return -1, ""
+	}
+
+	depth := 1
+	i := start
+
+	for i < len(text) && depth > 0 {
+		if text[i] == '{' {
+			depth++
+		} else if text[i] == '}' {
+			depth--
+			if depth == 0 {
+				return i + 1, text[start:i]
+			}
+		}
+		i++
+	}
+
+	return -1, ""
+}
+
+// handleSuperscripts converts ^{...} to Unicode superscripts where possible
+func handleSuperscripts(text string) string {
+	superscriptMap := map[rune]string{
+		'0': "⁰", '1': "¹", '2': "²", '3': "³", '4': "⁴",
+		'5': "⁵", '6': "⁶", '7': "⁷", '8': "⁸", '9': "⁹",
+		'a': "ᵃ", 'b': "ᵇ", 'c': "ᶜ", 'd': "ᵈ", 'e': "ᵉ",
+		'f': "ᶠ", 'g': "ᵍ", 'h': "ʰ", 'i': "ⁱ", 'j': "ʲ",
+		'k': "ᵏ", 'l': "ˡ", 'm': "ᵐ", 'n': "ⁿ", 'o': "ᵒ",
+		'p': "ᵖ", 'r': "ʳ", 's': "ˢ", 't': "ᵗ", 'u': "ᵘ",
+		'v': "ᵛ", 'w': "ʷ", 'x': "ˣ", 'y': "ʸ", 'z': "ᶻ",
+		'A': "ᴬ", 'B': "ᴮ", 'D': "ᴰ", 'E': "ᴱ", 'G': "ᴳ",
+		'H': "ᴴ", 'I': "ᴵ", 'J': "ᴶ", 'K': "ᴷ", 'L': "ᴸ",
+		'M': "ᴹ", 'N': "ᴺ", 'O': "ᴼ", 'P': "ᴾ", 'R': "ᴿ",
+		'T': "ᵀ", 'U': "ᵁ", 'V': "ⱽ", 'W': "ᵂ",
+		'+': "⁺", '-': "⁻", '=': "⁼", '(': "⁽", ')': "⁾",
+	}
+
+	result := text
+
+	// Handle ^{...} format
+	for {
+		start := strings.Index(result, "^{")
+		if start == -1 {
+			break
+		}
+
+		contentStart := start + 2
+		contentEnd, content := findBracedContent(result, contentStart)
+		if contentEnd == -1 {
+			break
+		}
+
+		// Convert content to superscript
+		var superscript strings.Builder
+		for _, ch := range content {
+			if sup, ok := superscriptMap[ch]; ok {
+				superscript.WriteString(sup)
+			} else {
+				// If no superscript version exists, wrap in parentheses
+				superscript.WriteRune(ch)
+			}
+		}
+
+		result = result[:start] + superscript.String() + result[contentEnd:]
+	}
+
+	// Handle simple ^x format (single character without braces)
+	for i := 0; i < len(result)-1; i++ {
+		if result[i] == '^' && result[i+1] != '{' {
+			ch := rune(result[i+1])
+			if sup, ok := superscriptMap[ch]; ok {
+				result = result[:i] + sup + result[i+2:]
+			}
+		}
+	}
+
+	return result
+}
+
+// handleSubscripts converts _{...} to Unicode subscripts where possible
+func handleSubscripts(text string) string {
+	subscriptMap := map[rune]string{
+		'0': "₀", '1': "₁", '2': "₂", '3': "₃", '4': "₄",
+		'5': "₅", '6': "₆", '7': "₇", '8': "₈", '9': "₉",
+		'a': "ₐ", 'e': "ₑ", 'h': "ₕ", 'i': "ᵢ", 'j': "ⱼ",
+		'k': "ₖ", 'l': "ₗ", 'm': "ₘ", 'n': "ₙ", 'o': "ₒ",
+		'p': "ₚ", 'r': "ᵣ", 's': "ₛ", 't': "ₜ", 'u': "ᵤ",
+		'v': "ᵥ", 'x': "ₓ",
+		'+': "₊", '-': "₋", '=': "₌", '(': "₍", ')': "₎",
+	}
+
+	result := text
+
+	// Handle _{...} format
+	for {
+		start := strings.Index(result, "_{")
+		if start == -1 {
+			break
+		}
+
+		contentStart := start + 2
+		contentEnd, content := findBracedContent(result, contentStart)
+		if contentEnd == -1 {
+			break
+		}
+
+		// Convert content to subscript
+		var subscript strings.Builder
+		for _, ch := range content {
+			if sub, ok := subscriptMap[ch]; ok {
+				subscript.WriteString(sub)
+			} else {
+				// If no subscript version exists, wrap in parentheses
+				subscript.WriteRune(ch)
+			}
+		}
+
+		result = result[:start] + subscript.String() + result[contentEnd:]
+	}
+
+	// Handle simple _x format (single character without braces)
+	for i := 0; i < len(result)-1; i++ {
+		if result[i] == '_' && result[i+1] != '{' {
+			ch := rune(result[i+1])
+			if sub, ok := subscriptMap[ch]; ok {
+				result = result[:i] + sub + result[i+2:]
+			}
+		}
+	}
+
+	return result
+}
+
 func (m uiModel) renderItem(item *model.Item, isCursor bool) string {
 	var b strings.Builder