From 5c4f2d6aff168303e28d478107c169c750bc9b39 Mon Sep 17 00:00:00 2001
From: Myzel394 <50424412+Myzel394@users.noreply.github.com>
Date: Sat, 12 Oct 2024 15:23:43 +0200
Subject: [PATCH] feat(server): Add concept of virtual lines

---
 server/common/parser/strings.go      |  54 ++++++-
 server/common/parser/strings_test.go |  26 ++++
 server/common/strings.go             |  23 +++
 server/common/virtual-line.go        | 205 +++++++++++++++++++++++++++
 server/common/virtual-line_test.go   | 182 ++++++++++++++++++++++++
 server/go.mod                        |   8 +-
 server/go.sum                        |   2 +
 server/utils/strings.go              |  64 +++++++++
 server/utils/strings_test.go         | 119 ++++++++++++++++
 9 files changed, 678 insertions(+), 5 deletions(-)
 create mode 100644 server/common/strings.go
 create mode 100644 server/common/virtual-line.go
 create mode 100644 server/common/virtual-line_test.go
 create mode 100644 server/utils/strings_test.go

diff --git a/server/common/parser/strings.go b/server/common/parser/strings.go
index 17aaee0..7e3f95b 100644
--- a/server/common/parser/strings.go
+++ b/server/common/parser/strings.go
@@ -1,16 +1,21 @@
 package parser
 
-import "strings"
+import (
+	"regexp"
+	"strings"
+)
 
 type ParseFeatures struct {
 	ParseDoubleQuotes      bool
 	ParseEscapedCharacters bool
+	TrimWhitespace         bool
 	Replacements           *map[string]string
 }
 
 var FullFeatures = ParseFeatures{
 	ParseDoubleQuotes:      true,
 	ParseEscapedCharacters: true,
+	TrimWhitespace:         false,
 	Replacements:           &map[string]string{},
 }
 
@@ -29,6 +34,10 @@ func ParseRawString(
 		value = ParseReplacements(value, *features.Replacements)
 	}
 
+	if features.TrimWhitespace {
+		value = TrimWhitespace(value, features.ParseDoubleQuotes)
+	}
+
 	// Parse double quotes
 	if features.ParseDoubleQuotes {
 		value = ParseDoubleQuotes(value)
@@ -45,6 +54,49 @@ func ParseRawString(
 	}
 }
 
+var trimPattern = regexp.MustCompile(`\s+`)
+
+func TrimWhitespace(
+	raw string,
+	respectDoubleQuotes bool,
+) string {
+	if !respectDoubleQuotes {
+		return trimPattern.ReplaceAllString(
+			strings.TrimSpace(raw),
+			" ",
+		)
+	}
+
+	value := raw
+	currentIndex := 0
+
+	for {
+		nextStart, found := findNextDoubleQuote(value, currentIndex)
+
+		if found {
+			part := value[:nextStart]
+			value = strings.TrimSpace(part) + value[nextStart:]
+		}
+
+		nextEnd, found := findNextDoubleQuote(value, nextStart+1)
+
+		if !found {
+			break
+		}
+
+		currentIndex = nextEnd + 1
+	}
+
+	// last part
+	if currentIndex < len(value) {
+		part := value[currentIndex:]
+
+		value = value[:currentIndex] + strings.TrimSpace(part)
+	}
+
+	return value
+}
+
 func ParseDoubleQuotes(
 	raw string,
 ) string {
diff --git a/server/common/parser/strings_test.go b/server/common/parser/strings_test.go
index 0a05916..fad0959 100644
--- a/server/common/parser/strings_test.go
+++ b/server/common/parser/strings_test.go
@@ -54,6 +54,32 @@ func TestStringsMultipleQuotesFullFeatures(
 	}
 }
 
+func TestTrimWhitespaceNoQuotes(
+	t *testing.T,
+) {
+	input := "  hello    world  "
+	expected := "hello world"
+
+	actual := TrimWhitespace(input, false)
+
+	if expected != actual {
+		t.Errorf("Expected %v, got %v", expected, actual)
+	}
+}
+
+func TestTrimWhitespaceQuotes(
+	t *testing.T,
+) {
+	input := `  "hello    world"  `
+	expected := `"hello    world"`
+
+	actual := TrimWhitespace(input, true)
+
+	if expected != actual {
+		t.Errorf("Expected %v, got %v", expected, actual)
+	}
+}
+
 func TestStringsSimpleEscapedFullFeatures(
 	t *testing.T,
 ) {
diff --git a/server/common/strings.go b/server/common/strings.go
new file mode 100644
index 0000000..75a0494
--- /dev/null
+++ b/server/common/strings.go
@@ -0,0 +1,23 @@
+package common
+
+var UnicodeWhitespace = map[rune]struct{}{
+	'\u0020': {}, // Space
+	'\u0009': {}, // Horizontal tab
+	'\u000A': {}, // Line feed
+	'\u000B': {}, // Vertical tab
+	'\u000C': {}, // Form feed
+	'\u000D': {}, // Carriage return
+	'\u0085': {}, // Next line
+	'\u00A0': {}, // No-break space
+	'\u1680': {}, // Ogham space mark
+	'\u2000': {}, // En quad
+	'\u2001': {}, // Em quad
+	'\u2002': {}, // En space
+	'\u2003': {}, // Em space
+	'\u2004': {}, // Three-per-em space
+	'\u2005': {}, // Four-per-em space
+	'\u2006': {}, // Six-per-em space
+	'\u2007': {}, // Figure space
+	'\u2008': {}, // Punctuation space
+	'\u2009': {}, // Thin space
+}
diff --git a/server/common/virtual-line.go b/server/common/virtual-line.go
new file mode 100644
index 0000000..27f7341
--- /dev/null
+++ b/server/common/virtual-line.go
@@ -0,0 +1,205 @@
+package common
+
+import (
+	"config-lsp/utils"
+)
+
+type VirtualLine struct {
+	// This is the true location of the text
+	// This ranges from the start of the first line and character
+	// to the end of the last line and character
+	LocationRange
+
+	Parts []VirtualLinePart
+}
+
+func (l VirtualLine) GetText() string {
+	text := ""
+
+	for _, part := range l.Parts {
+		text += part.Text
+	}
+
+	return text
+}
+
+// GetSubset Get a subset of the virtual line starting from `start` and ending at `end`
+func (l VirtualLine) GetSubset(start uint32, end uint32) VirtualLine {
+	parts := make([]VirtualLinePart, 0, 5)
+	currentIndex := uint32(0)
+
+	for _, part := range l.Parts {
+		partStart := currentIndex
+		partEnd := currentIndex + uint32(len(part.Text))
+
+		if partEnd < start {
+			continue
+		}
+
+		if start <= partEnd {
+			var rangeStart uint32
+			var rangeEnd uint32
+
+			if start >= partStart {
+				rangeStart = start - partStart
+			} else {
+				rangeStart = 0
+			}
+
+			if end <= partEnd {
+				rangeEnd = end - partStart
+			} else {
+				rangeEnd = partEnd
+			}
+
+			parts = append(parts, VirtualLinePart{
+				LocationRange: LocationRange{
+					Start: Location{
+						Line:      part.Start.Line,
+						Character: part.Start.Character + rangeStart,
+					},
+					End: Location{
+						Line:      part.Start.Line,
+						Character: part.Start.Character + rangeEnd,
+					},
+				},
+				Text: part.Text[rangeStart:rangeEnd],
+			})
+		}
+
+		currentIndex = partEnd
+
+		if currentIndex >= end {
+			break
+		}
+	}
+
+	return VirtualLine{
+		LocationRange: LocationRange{
+			Start: parts[0].Start,
+			End:   parts[len(parts)-1].End,
+		},
+		Parts: parts,
+	}
+}
+
+// ConvertRangeToTextRange Convert a given start and end range to a text range
+// start and end are the start and end ranges of the virtual line
+// This will return the start and end ranges of the actual text lines so that they
+// match to the text of the virtual line
+// The `start` and `end` are expected to be within the range of the virtual line
+func (l VirtualLine) ConvertRangeToTextRange(start uint32, end uint32) []LocationRange {
+	virtualLine := l.GetSubset(start, end)
+
+	ranges := make([]LocationRange, 0, 5)
+
+	for _, part := range virtualLine.Parts {
+		ranges = append(ranges, part.LocationRange)
+	}
+
+	return ranges
+}
+
+func (l VirtualLine) AsTrimmed() VirtualLine {
+	if len(l.Parts) == 0 {
+		// There's nothing that could be trimmed, so we can also just
+		// return the original line, as it's identical
+		return l
+	}
+
+	parts := make([]VirtualLinePart, len(l.Parts))
+
+	for index, part := range l.Parts {
+		parts[index] = part.AsTrimmed()
+	}
+
+	return VirtualLine{
+		LocationRange: LocationRange{
+			Start: parts[0].Start,
+			End:   parts[len(parts)-1].End,
+		},
+		Parts: parts,
+	}
+}
+
+type VirtualLinePart struct {
+	// This is the true location of the text
+	LocationRange
+
+	Text string
+}
+
+func (p VirtualLinePart) AsTrimmed() VirtualLinePart {
+	firstNonWhitespace := utils.FindFirstNonMatch(p.Text, UnicodeWhitespace, 0)
+
+	if firstNonWhitespace == -1 {
+		// Empty line
+		return p
+	}
+
+	lastNonWhitespace := utils.FindLastNonMatch(p.Text, UnicodeWhitespace, len(p.Text)-1)
+
+	if lastNonWhitespace == -1 {
+		lastNonWhitespace = len(p.Text) - 1
+	}
+
+	return VirtualLinePart{
+		LocationRange: LocationRange{
+			Start: Location{
+				Line:      p.Start.Line,
+				Character: p.Start.Character + uint32(firstNonWhitespace),
+			},
+			End: Location{
+				Line:      p.Start.Line,
+				Character: p.Start.Character + uint32(lastNonWhitespace) + 1,
+			},
+		},
+		Text: p.Text[firstNonWhitespace : lastNonWhitespace+1],
+	}
+}
+
+func SplitIntoVirtualLines(input string) []VirtualLine {
+	stringLines := utils.SplitIntoVirtualLines(input)
+
+	lines := make([]VirtualLine, 0, len(stringLines))
+
+	for rawLineNumber, line := range stringLines {
+		parts := make([]VirtualLinePart, 0)
+
+		for virtualLineNumber, part := range line {
+			if part == "" {
+				continue
+			}
+
+			lineNumber := uint32(rawLineNumber) + uint32(virtualLineNumber)
+
+			parts = append(parts, VirtualLinePart{
+				LocationRange: LocationRange{
+					Start: Location{
+						Line:      lineNumber,
+						Character: 0,
+					},
+					End: Location{
+						Line:      lineNumber,
+						Character: uint32(len(part)),
+					},
+				},
+				Text: part,
+			})
+		}
+
+		if len(parts) == 0 {
+			continue
+		}
+
+		lines = append(lines, VirtualLine{
+			LocationRange: LocationRange{
+				Start: parts[0].Start,
+				End:   parts[len(parts)-1].End,
+			},
+			Parts: parts,
+		})
+	}
+
+	return lines
+}
diff --git a/server/common/virtual-line_test.go b/server/common/virtual-line_test.go
new file mode 100644
index 0000000..c7aa748
--- /dev/null
+++ b/server/common/virtual-line_test.go
@@ -0,0 +1,182 @@
+package common
+
+import (
+	"config-lsp/utils"
+	"github.com/google/go-cmp/cmp"
+	"testing"
+)
+
+func TestSplitIntoVirtualLinesSimpleExample(
+	t *testing.T,
+) {
+	input := utils.Dedent(`
+Hello
+World \
+how are you
+`)
+	expected := []VirtualLine{
+		{
+			LocationRange: LocationRange{
+				Start: Location{
+					Line:      0,
+					Character: 0,
+				},
+				End: Location{
+					Line:      0,
+					Character: 5,
+				},
+			},
+			Parts: []VirtualLinePart{
+				{
+					LocationRange: LocationRange{
+						Start: Location{
+							Line:      0,
+							Character: 0,
+						},
+						End: Location{
+							Line:      0,
+							Character: 5,
+						},
+					},
+					Text: "Hello",
+				},
+			},
+		},
+		{
+			LocationRange: LocationRange{
+				Start: Location{
+					Line:      1,
+					Character: 0,
+				},
+				End: Location{
+					Line:      2,
+					Character: 11,
+				},
+			},
+			Parts: []VirtualLinePart{
+				{
+					LocationRange: LocationRange{
+						Start: Location{
+							Line:      1,
+							Character: 0,
+						},
+						End: Location{
+							Line:      1,
+							Character: 6,
+						},
+					},
+					Text: "World ",
+				},
+				{
+					LocationRange: LocationRange{
+						Start: Location{
+							Line:      2,
+							Character: 0,
+						},
+						End: Location{
+							Line:      2,
+							Character: 11,
+						},
+					},
+					Text: "how are you",
+				},
+			},
+		},
+	}
+
+	lines := SplitIntoVirtualLines(input)
+
+	if !cmp.Equal(expected, lines) {
+		t.Fatalf("Expected %v, got %v", expected, lines)
+	}
+
+	expectedText := "World how are you"
+	actualText := lines[1].GetText()
+
+	if expectedText != actualText {
+		t.Fatalf("Expected %v, got %v", expectedText, actualText)
+	}
+
+	expectedText = "rld how are"
+	actualText = lines[1].GetText()[2:13]
+
+	if expectedText != actualText {
+		t.Fatalf("Expected %v, got %v", expectedText, actualText)
+	}
+
+	expectedRanges := []LocationRange{
+		{
+			Start: Location{
+				Line:      1,
+				Character: 2,
+			},
+			End: Location{
+				Line:      1,
+				Character: 6,
+			},
+		},
+		{
+			Start: Location{
+				Line:      2,
+				Character: 0,
+			},
+			End: Location{
+				Line:      2,
+				Character: 7,
+			},
+		},
+	}
+	actualRanges := lines[1].ConvertRangeToTextRange(2, 13)
+
+	if !cmp.Equal(expectedRanges, actualRanges) {
+		t.Fatalf("Expected %v, got %v", expectedRanges, actualRanges)
+	}
+}
+
+func TestSplitIntoVirtualLinesIndentedExample(
+	t *testing.T,
+) {
+	// 4 spaces
+	input := utils.Dedent(`
+    Hello
+`)
+	expected := []VirtualLine{
+		{
+			LocationRange: LocationRange{
+				Start: Location{
+					Line:      0,
+					Character: 4,
+				},
+				End: Location{
+					Line:      0,
+					Character: 9,
+				},
+			},
+			Parts: []VirtualLinePart{
+				{
+					LocationRange: LocationRange{
+						Start: Location{
+							Line:      0,
+							Character: 4,
+						},
+						End: Location{
+							Line:      0,
+							Character: 9,
+						},
+					},
+					Text: "Hello",
+				},
+			},
+		},
+	}
+
+	actual := SplitIntoVirtualLines(input)
+
+	for index, line := range actual {
+		actual[index] = line.AsTrimmed()
+	}
+
+	if !cmp.Equal(expected, actual) {
+		t.Fatalf("Expected %v, got %v", expected, actual)
+	}
+}
diff --git a/server/go.mod b/server/go.mod
index 8c84359..cb117fe 100644
--- a/server/go.mod
+++ b/server/go.mod
@@ -3,15 +3,16 @@ module config-lsp
 go 1.22.5
 
 require (
+	github.com/antlr4-go/antlr/v4 v4.13.1
+	github.com/emirpasic/gods v1.18.1
 	github.com/tliron/commonlog v0.2.17
 	github.com/tliron/glsp v0.2.2
+	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56
+	github.com/google/go-cmp v0.6.0
 )
 
 require (
-	github.com/antlr4-go/antlr/v4 v4.13.1 // indirect
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
-	github.com/emirpasic/gods v1.18.1 // indirect
-	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/gorilla/websocket v1.5.3 // indirect
 	github.com/iancoleman/strcase v0.3.0 // indirect
 	github.com/k0kubun/pp v3.0.1+incompatible // indirect
@@ -28,7 +29,6 @@ require (
 	github.com/sourcegraph/jsonrpc2 v0.2.0 // indirect
 	github.com/tliron/kutil v0.3.24 // indirect
 	golang.org/x/crypto v0.25.0 // indirect
-	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56 // indirect
 	golang.org/x/sys v0.22.0 // indirect
 	golang.org/x/term v0.22.0 // indirect
 )
diff --git a/server/go.sum b/server/go.sum
index 100a1f7..70ef9af 100644
--- a/server/go.sum
+++ b/server/go.sum
@@ -4,6 +4,8 @@ github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiE
 github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
 github.com/emirpasic/gods v1.18.1 h1:FXtiHYKDGKCW2KzwZKx0iC0PQmdlorYgdFG9jPXJ1Bc=
 github.com/emirpasic/gods v1.18.1/go.mod h1:8tpGGwCnJ5H4r6BWwaV6OrWmMoPhUl5jm/FMNAnJvWQ=
+github.com/fatih/color v1.17.0 h1:GlRw1BRJxkpqUCBKzKOw098ed57fEsKeNjpTe3cSjK4=
+github.com/fatih/color v1.17.0/go.mod h1:YZ7TlrGPkiz6ku9fK3TLD/pl3CpsiFyu8N92HLgmosI=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/gorilla/websocket v1.4.1/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
diff --git a/server/utils/strings.go b/server/utils/strings.go
index 3f7f851..192f34a 100644
--- a/server/utils/strings.go
+++ b/server/utils/strings.go
@@ -76,3 +76,67 @@ func AllIndexes(s string, sub string) []int {
 
 	return indexes
 }
+
+func FindFirstNonMatch(s string, substr map[rune]struct{}, startIndex int) int {
+	for index := startIndex; index < len(s); index++ {
+		if _, found := substr[rune(s[index])]; !found {
+			return index
+		}
+	}
+
+	return -1
+}
+
+func FindLastNonMatch(s string, substr map[rune]struct{}, startIndex int) int {
+	for index := startIndex; index >= 0; index-- {
+		if _, found := substr[rune(s[index])]; !found {
+			return index
+		}
+	}
+
+	return -1
+}
+
+var lineContinuationPattern = regexp.MustCompile(`\\\s*$`)
+
+// SplitSmartlyIntoLines Split a string into lines while respecting "\" as a line continuation character
+// This function is useful for parsing configuration files
+// You will need to handle whitespace trimming yourself
+// For example, the following input:
+// ```
+// key1 = value1
+//
+//	key2 = value2 \
+//	    value3
+//
+// key3 = value4
+// ```
+// Will be split into:
+// ```go
+//
+//	[][]string{
+//		[]string{"key1 = value1"},
+//		[]string{"key2 = value2 ", "    value3"},
+//		[]string{"key3 = value4"},
+//	}
+func SplitIntoVirtualLines(input string) [][]string {
+	lines := make([][]string, 0, len(input))
+	currentLine := make([]string, 0, 1)
+
+	for _, line := range SplitIntoLines(input) {
+		if lineContinuationPattern.MatchString(line) {
+			currentLine = append(currentLine, line[:len(line)-1])
+			continue
+		}
+
+		currentLine = append(currentLine, line)
+		lines = append(lines, currentLine)
+		currentLine = make([]string, 0, 1)
+	}
+
+	if len(currentLine) > 0 {
+		lines = append(lines, currentLine)
+	}
+
+	return lines
+}
diff --git a/server/utils/strings_test.go b/server/utils/strings_test.go
new file mode 100644
index 0000000..81b6287
--- /dev/null
+++ b/server/utils/strings_test.go
@@ -0,0 +1,119 @@
+package utils
+
+import (
+	"github.com/google/go-cmp/cmp"
+	"testing"
+)
+
+func TestSplitIntoVirtualLinesSimpleExample(
+	t *testing.T,
+) {
+	input := Dedent(`
+Hello
+World\
+how are you
+`)
+	expected := [][]string{
+		{"Hello"},
+		{"World", "how are you"},
+	}
+
+	actual := SplitIntoVirtualLines(input)
+
+	if cmp.Equal(expected, actual) {
+		t.Fatalf("Expected %v, got %v", expected, actual)
+	}
+}
+
+func TestSplitIntoVirtualLinesEmptyString(t *testing.T) {
+	input := ""
+	expected := [][]string{
+		{""},
+	}
+
+	actual := SplitIntoVirtualLines(input)
+
+	if !cmp.Equal(expected, actual) {
+		t.Fatalf("Expected %v, got %v", expected, actual)
+	}
+}
+
+func TestSplitIntoVirtualLinesSingleLine(t *testing.T) {
+	input := Dedent(`
+    Hello`)
+	expected := [][]string{
+		{"    Hello"},
+	}
+
+	actual := SplitIntoVirtualLines(input)
+
+	if !cmp.Equal(expected, actual) {
+		t.Fatalf("Expected %v, got %v", expected, actual)
+	}
+}
+
+func TestSplitIntoVirtualLinesMultipleLinesWithoutContinuation(t *testing.T) {
+	input := Dedent(`
+    Hello
+    World
+    How are you`)
+	expected := [][]string{
+		{"    Hello"},
+		{"    World"},
+		{"    How are you"},
+	}
+
+	actual := SplitIntoVirtualLines(input)
+
+	if !cmp.Equal(expected, actual) {
+		t.Fatalf("Expected %v, got %v", expected, actual)
+	}
+}
+
+func TestSplitIntoVirtualLinesMultipleLinesWithContinuation(t *testing.T) {
+	input := Dedent(`
+    Hello \
+World \
+How are you`)
+	expected := [][]string{
+		{"    Hello ", "World ", "How are you"},
+	}
+
+	actual := SplitIntoVirtualLines(input)
+
+	if !cmp.Equal(expected, actual) {
+		t.Fatalf("Expected %v, got %v", expected, actual)
+	}
+}
+
+func TestSplitIntoVirtualLinesMixedContinuation(t *testing.T) {
+	input := Dedent(`
+Hello
+World\
+    How are you`)
+	expected := [][]string{
+		{"Hello"},
+		{"World", "    How are you"},
+	}
+
+	actual := SplitIntoVirtualLines(input)
+
+	if !cmp.Equal(expected, actual) {
+		t.Fatalf("Expected %v, got %v", expected, actual)
+	}
+}
+
+func TestSplitIntoVirtualLinesTrailingContinuation(t *testing.T) {
+	input := Dedent(`
+Hello\
+    `)
+	expected := [][]string{
+		{"Hello", "    "},
+	}
+
+	actual := SplitIntoVirtualLines(input)
+
+	if !cmp.Equal(expected, actual) {
+		t.Fatalf("Expected %v, got %v", expected, actual)
+	}
+}