implement patch, update ui, improve rendering

internal/diff/diff.go

@@ -79,8 +79,9 @@ type linePair struct {
 
 // StyleConfig defines styling for diff rendering
 type StyleConfig struct {
-	ShowHeader bool
-	FileNameFg lipgloss.Color
+	ShowHeader     bool
+	ShowHunkHeader bool
+	FileNameFg     lipgloss.Color
 	// Background colors
 	RemovedLineBg       lipgloss.Color
 	AddedLineBg         lipgloss.Color
@@ -111,7 +112,8 @@ func NewStyleConfig(opts ...StyleOption) StyleConfig {
 	// Default color scheme
 	config := StyleConfig{
 		ShowHeader:          true,
-		FileNameFg:          lipgloss.Color("#fab283"),
+		ShowHunkHeader:      true,
+		FileNameFg:          lipgloss.Color("#a0a0a0"),
 		RemovedLineBg:       lipgloss.Color("#3A3030"),
 		AddedLineBg:         lipgloss.Color("#303A30"),
 		ContextLineBg:       lipgloss.Color("#212121"),
@@ -204,6 +206,10 @@ func WithShowHeader(show bool) StyleOption {
 	return func(s *StyleConfig) { s.ShowHeader = show }
 }
 
+func WithShowHunkHeader(show bool) StyleOption {
+	return func(s *StyleConfig) { s.ShowHunkHeader = show }
+}
+
 // -------------------------------------------------------------------------
 // Parse Configuration
 // -------------------------------------------------------------------------
@@ -914,13 +920,15 @@ func FormatDiff(diffText string, opts ...SideBySideOption) (string, error) {
 
 	for _, h := range diffResult.Hunks {
 		// Render hunk header
-		sb.WriteString(
-			lipgloss.NewStyle().
-				Background(config.Style.HunkLineBg).
-				Foreground(config.Style.HunkLineFg).
-				Width(config.TotalWidth).
-				Render(h.Header) + "\n",
-		)
+		if config.Style.ShowHunkHeader {
+			sb.WriteString(
+				lipgloss.NewStyle().
+					Background(config.Style.HunkLineBg).
+					Foreground(config.Style.HunkLineFg).
+					Width(config.TotalWidth).
+					Render(h.Header) + "\n",
+			)
+		}
 		sb.WriteString(RenderSideBySideHunk(diffResult.OldFile, h, opts...))
 	}
 

internal/diff/patch.go

@@ -0,0 +1,739 @@
+package diff
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+type ActionType string
+
+const (
+	ActionAdd    ActionType = "add"
+	ActionDelete ActionType = "delete"
+	ActionUpdate ActionType = "update"
+)
+
+type FileChange struct {
+	Type       ActionType
+	OldContent *string
+	NewContent *string
+	MovePath   *string
+}
+
+type Commit struct {
+	Changes map[string]FileChange
+}
+
+type Chunk struct {
+	OrigIndex int      // line index of the first line in the original file
+	DelLines  []string // lines to delete
+	InsLines  []string // lines to insert
+}
+
+type PatchAction struct {
+	Type     ActionType
+	NewFile  *string
+	Chunks   []Chunk
+	MovePath *string
+}
+
+type Patch struct {
+	Actions map[string]PatchAction
+}
+
+type DiffError struct {
+	message string
+}
+
+func (e DiffError) Error() string {
+	return e.message
+}
+
+// Helper functions for error handling
+func NewDiffError(message string) DiffError {
+	return DiffError{message: message}
+}
+
+func fileError(action, reason, path string) DiffError {
+	return NewDiffError(fmt.Sprintf("%s File Error: %s: %s", action, reason, path))
+}
+
+func contextError(index int, context string, isEOF bool) DiffError {
+	prefix := "Invalid Context"
+	if isEOF {
+		prefix = "Invalid EOF Context"
+	}
+	return NewDiffError(fmt.Sprintf("%s %d:\n%s", prefix, index, context))
+}
+
+type Parser struct {
+	currentFiles map[string]string
+	lines        []string
+	index        int
+	patch        Patch
+	fuzz         int
+}
+
+func NewParser(currentFiles map[string]string, lines []string) *Parser {
+	return &Parser{
+		currentFiles: currentFiles,
+		lines:        lines,
+		index:        0,
+		patch:        Patch{Actions: make(map[string]PatchAction, len(currentFiles))},
+		fuzz:         0,
+	}
+}
+
+func (p *Parser) isDone(prefixes []string) bool {
+	if p.index >= len(p.lines) {
+		return true
+	}
+	if prefixes != nil {
+		for _, prefix := range prefixes {
+			if strings.HasPrefix(p.lines[p.index], prefix) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func (p *Parser) startsWith(prefix any) bool {
+	var prefixes []string
+	switch v := prefix.(type) {
+	case string:
+		prefixes = []string{v}
+	case []string:
+		prefixes = v
+	}
+
+	for _, pfx := range prefixes {
+		if strings.HasPrefix(p.lines[p.index], pfx) {
+			return true
+		}
+	}
+	return false
+}
+
+func (p *Parser) readStr(prefix string, returnEverything bool) string {
+	if p.index >= len(p.lines) {
+		return "" // Changed from panic to return empty string for safer operation
+	}
+	if strings.HasPrefix(p.lines[p.index], prefix) {
+		var text string
+		if returnEverything {
+			text = p.lines[p.index]
+		} else {
+			text = p.lines[p.index][len(prefix):]
+		}
+		p.index++
+		return text
+	}
+	return ""
+}
+
+func (p *Parser) Parse() error {
+	endPatchPrefixes := []string{"*** End Patch"}
+
+	for !p.isDone(endPatchPrefixes) {
+		path := p.readStr("*** Update File: ", false)
+		if path != "" {
+			if _, exists := p.patch.Actions[path]; exists {
+				return fileError("Update", "Duplicate Path", path)
+			}
+			moveTo := p.readStr("*** Move to: ", false)
+			if _, exists := p.currentFiles[path]; !exists {
+				return fileError("Update", "Missing File", path)
+			}
+			text := p.currentFiles[path]
+			action, err := p.parseUpdateFile(text)
+			if err != nil {
+				return err
+			}
+			if moveTo != "" {
+				action.MovePath = &moveTo
+			}
+			p.patch.Actions[path] = action
+			continue
+		}
+
+		path = p.readStr("*** Delete File: ", false)
+		if path != "" {
+			if _, exists := p.patch.Actions[path]; exists {
+				return fileError("Delete", "Duplicate Path", path)
+			}
+			if _, exists := p.currentFiles[path]; !exists {
+				return fileError("Delete", "Missing File", path)
+			}
+			p.patch.Actions[path] = PatchAction{Type: ActionDelete, Chunks: []Chunk{}}
+			continue
+		}
+
+		path = p.readStr("*** Add File: ", false)
+		if path != "" {
+			if _, exists := p.patch.Actions[path]; exists {
+				return fileError("Add", "Duplicate Path", path)
+			}
+			if _, exists := p.currentFiles[path]; exists {
+				return fileError("Add", "File already exists", path)
+			}
+			action, err := p.parseAddFile()
+			if err != nil {
+				return err
+			}
+			p.patch.Actions[path] = action
+			continue
+		}
+
+		return NewDiffError(fmt.Sprintf("Unknown Line: %s", p.lines[p.index]))
+	}
+
+	if !p.startsWith("*** End Patch") {
+		return NewDiffError("Missing End Patch")
+	}
+	p.index++
+
+	return nil
+}
+
+func (p *Parser) parseUpdateFile(text string) (PatchAction, error) {
+	action := PatchAction{Type: ActionUpdate, Chunks: []Chunk{}}
+	fileLines := strings.Split(text, "\n")
+	index := 0
+
+	endPrefixes := []string{
+		"*** End Patch",
+		"*** Update File:",
+		"*** Delete File:",
+		"*** Add File:",
+		"*** End of File",
+	}
+
+	for !p.isDone(endPrefixes) {
+		defStr := p.readStr("@@ ", false)
+		sectionStr := ""
+		if defStr == "" && p.index < len(p.lines) && p.lines[p.index] == "@@" {
+			sectionStr = p.lines[p.index]
+			p.index++
+		}
+		if !(defStr != "" || sectionStr != "" || index == 0) {
+			return action, NewDiffError(fmt.Sprintf("Invalid Line:\n%s", p.lines[p.index]))
+		}
+		if strings.TrimSpace(defStr) != "" {
+			found := false
+			for i := range fileLines[:index] {
+				if fileLines[i] == defStr {
+					found = true
+					break
+				}
+			}
+
+			if !found {
+				for i := index; i < len(fileLines); i++ {
+					if fileLines[i] == defStr {
+						index = i + 1
+						found = true
+						break
+					}
+				}
+			}
+
+			if !found {
+				for i := range fileLines[:index] {
+					if strings.TrimSpace(fileLines[i]) == strings.TrimSpace(defStr) {
+						found = true
+						break
+					}
+				}
+			}
+
+			if !found {
+				for i := index; i < len(fileLines); i++ {
+					if strings.TrimSpace(fileLines[i]) == strings.TrimSpace(defStr) {
+						index = i + 1
+						p.fuzz++
+						found = true
+						break
+					}
+				}
+			}
+		}
+
+		nextChunkContext, chunks, endPatchIndex, eof := peekNextSection(p.lines, p.index)
+		newIndex, fuzz := findContext(fileLines, nextChunkContext, index, eof)
+		if newIndex == -1 {
+			ctxText := strings.Join(nextChunkContext, "\n")
+			return action, contextError(index, ctxText, eof)
+		}
+		p.fuzz += fuzz
+
+		for _, ch := range chunks {
+			ch.OrigIndex += newIndex
+			action.Chunks = append(action.Chunks, ch)
+		}
+		index = newIndex + len(nextChunkContext)
+		p.index = endPatchIndex
+	}
+	return action, nil
+}
+
+func (p *Parser) parseAddFile() (PatchAction, error) {
+	lines := make([]string, 0, 16) // Preallocate space for better performance
+	endPrefixes := []string{
+		"*** End Patch",
+		"*** Update File:",
+		"*** Delete File:",
+		"*** Add File:",
+	}
+
+	for !p.isDone(endPrefixes) {
+		s := p.readStr("", true)
+		if !strings.HasPrefix(s, "+") {
+			return PatchAction{}, NewDiffError(fmt.Sprintf("Invalid Add File Line: %s", s))
+		}
+		lines = append(lines, s[1:])
+	}
+
+	newFile := strings.Join(lines, "\n")
+	return PatchAction{
+		Type:    ActionAdd,
+		NewFile: &newFile,
+		Chunks:  []Chunk{},
+	}, nil
+}
+
+// Refactored to use a matcher function for each comparison type
+func findContextCore(lines []string, context []string, start int) (int, int) {
+	if len(context) == 0 {
+		return start, 0
+	}
+
+	// Try exact match
+	if idx, fuzz := tryFindMatch(lines, context, start, func(a, b string) bool {
+		return a == b
+	}); idx >= 0 {
+		return idx, fuzz
+	}
+
+	// Try trimming right whitespace
+	if idx, fuzz := tryFindMatch(lines, context, start, func(a, b string) bool {
+		return strings.TrimRight(a, " \t") == strings.TrimRight(b, " \t")
+	}); idx >= 0 {
+		return idx, fuzz
+	}
+
+	// Try trimming all whitespace
+	if idx, fuzz := tryFindMatch(lines, context, start, func(a, b string) bool {
+		return strings.TrimSpace(a) == strings.TrimSpace(b)
+	}); idx >= 0 {
+		return idx, fuzz
+	}
+
+	return -1, 0
+}
+
+// Helper function to DRY up the match logic
+func tryFindMatch(lines []string, context []string, start int,
+	compareFunc func(string, string) bool,
+) (int, int) {
+	for i := start; i < len(lines); i++ {
+		if i+len(context) <= len(lines) {
+			match := true
+			for j := range context {
+				if !compareFunc(lines[i+j], context[j]) {
+					match = false
+					break
+				}
+			}
+			if match {
+				// Return fuzz level: 0 for exact, 1 for trimRight, 100 for trimSpace
+				var fuzz int
+				if compareFunc("a ", "a") && !compareFunc("a", "b") {
+					fuzz = 1
+				} else if compareFunc("a  ", "a") {
+					fuzz = 100
+				}
+				return i, fuzz
+			}
+		}
+	}
+	return -1, 0
+}
+
+func findContext(lines []string, context []string, start int, eof bool) (int, int) {
+	if eof {
+		newIndex, fuzz := findContextCore(lines, context, len(lines)-len(context))
+		if newIndex != -1 {
+			return newIndex, fuzz
+		}
+		newIndex, fuzz = findContextCore(lines, context, start)
+		return newIndex, fuzz + 10000
+	}
+	return findContextCore(lines, context, start)
+}
+
+func peekNextSection(lines []string, initialIndex int) ([]string, []Chunk, int, bool) {
+	index := initialIndex
+	old := make([]string, 0, 32) // Preallocate for better performance
+	delLines := make([]string, 0, 8)
+	insLines := make([]string, 0, 8)
+	chunks := make([]Chunk, 0, 4)
+	mode := "keep"
+
+	// End conditions for the section
+	endSectionConditions := func(s string) bool {
+		return strings.HasPrefix(s, "@@") ||
+			strings.HasPrefix(s, "*** End Patch") ||
+			strings.HasPrefix(s, "*** Update File:") ||
+			strings.HasPrefix(s, "*** Delete File:") ||
+			strings.HasPrefix(s, "*** Add File:") ||
+			strings.HasPrefix(s, "*** End of File") ||
+			s == "***" ||
+			strings.HasPrefix(s, "***")
+	}
+
+	for index < len(lines) {
+		s := lines[index]
+		if endSectionConditions(s) {
+			break
+		}
+		index++
+		lastMode := mode
+		line := s
+
+		if len(line) > 0 {
+			switch line[0] {
+			case '+':
+				mode = "add"
+			case '-':
+				mode = "delete"
+			case ' ':
+				mode = "keep"
+			default:
+				mode = "keep"
+				line = " " + line
+			}
+		} else {
+			mode = "keep"
+			line = " "
+		}
+
+		line = line[1:]
+		if mode == "keep" && lastMode != mode {
+			if len(insLines) > 0 || len(delLines) > 0 {
+				chunks = append(chunks, Chunk{
+					OrigIndex: len(old) - len(delLines),
+					DelLines:  delLines,
+					InsLines:  insLines,
+				})
+			}
+			delLines = make([]string, 0, 8)
+			insLines = make([]string, 0, 8)
+		}
+		if mode == "delete" {
+			delLines = append(delLines, line)
+			old = append(old, line)
+		} else if mode == "add" {
+			insLines = append(insLines, line)
+		} else {
+			old = append(old, line)
+		}
+	}
+
+	if len(insLines) > 0 || len(delLines) > 0 {
+		chunks = append(chunks, Chunk{
+			OrigIndex: len(old) - len(delLines),
+			DelLines:  delLines,
+			InsLines:  insLines,
+		})
+	}
+
+	if index < len(lines) && lines[index] == "*** End of File" {
+		index++
+		return old, chunks, index, true
+	}
+	return old, chunks, index, false
+}
+
+func TextToPatch(text string, orig map[string]string) (Patch, int, error) {
+	text = strings.TrimSpace(text)
+	lines := strings.Split(text, "\n")
+	if len(lines) < 2 || !strings.HasPrefix(lines[0], "*** Begin Patch") || lines[len(lines)-1] != "*** End Patch" {
+		return Patch{}, 0, NewDiffError("Invalid patch text")
+	}
+	parser := NewParser(orig, lines)
+	parser.index = 1
+	if err := parser.Parse(); err != nil {
+		return Patch{}, 0, err
+	}
+	return parser.patch, parser.fuzz, nil
+}
+
+func IdentifyFilesNeeded(text string) []string {
+	text = strings.TrimSpace(text)
+	lines := strings.Split(text, "\n")
+	result := make(map[string]bool)
+
+	for _, line := range lines {
+		if strings.HasPrefix(line, "*** Update File: ") {
+			result[line[len("*** Update File: "):]] = true
+		}
+		if strings.HasPrefix(line, "*** Delete File: ") {
+			result[line[len("*** Delete File: "):]] = true
+		}
+	}
+
+	files := make([]string, 0, len(result))
+	for file := range result {
+		files = append(files, file)
+	}
+	return files
+}
+
+func IdentifyFilesAdded(text string) []string {
+	text = strings.TrimSpace(text)
+	lines := strings.Split(text, "\n")
+	result := make(map[string]bool)
+
+	for _, line := range lines {
+		if strings.HasPrefix(line, "*** Add File: ") {
+			result[line[len("*** Add File: "):]] = true
+		}
+	}
+
+	files := make([]string, 0, len(result))
+	for file := range result {
+		files = append(files, file)
+	}
+	return files
+}
+
+func getUpdatedFile(text string, action PatchAction, path string) (string, error) {
+	if action.Type != ActionUpdate {
+		return "", errors.New("Expected UPDATE action")
+	}
+	origLines := strings.Split(text, "\n")
+	destLines := make([]string, 0, len(origLines)) // Preallocate with capacity
+	origIndex := 0
+
+	for _, chunk := range action.Chunks {
+		if chunk.OrigIndex > len(origLines) {
+			return "", NewDiffError(fmt.Sprintf("%s: chunk.orig_index %d > len(lines) %d", path, chunk.OrigIndex, len(origLines)))
+		}
+		if origIndex > chunk.OrigIndex {
+			return "", NewDiffError(fmt.Sprintf("%s: orig_index %d > chunk.orig_index %d", path, origIndex, chunk.OrigIndex))
+		}
+		destLines = append(destLines, origLines[origIndex:chunk.OrigIndex]...)
+		delta := chunk.OrigIndex - origIndex
+		origIndex += delta
+
+		if len(chunk.InsLines) > 0 {
+			destLines = append(destLines, chunk.InsLines...)
+		}
+		origIndex += len(chunk.DelLines)
+	}
+
+	destLines = append(destLines, origLines[origIndex:]...)
+	return strings.Join(destLines, "\n"), nil
+}
+
+func PatchToCommit(patch Patch, orig map[string]string) (Commit, error) {
+	commit := Commit{Changes: make(map[string]FileChange, len(patch.Actions))}
+	for pathKey, action := range patch.Actions {
+		if action.Type == ActionDelete {
+			oldContent := orig[pathKey]
+			commit.Changes[pathKey] = FileChange{
+				Type:       ActionDelete,
+				OldContent: &oldContent,
+			}
+		} else if action.Type == ActionAdd {
+			commit.Changes[pathKey] = FileChange{
+				Type:       ActionAdd,
+				NewContent: action.NewFile,
+			}
+		} else if action.Type == ActionUpdate {
+			newContent, err := getUpdatedFile(orig[pathKey], action, pathKey)
+			if err != nil {
+				return Commit{}, err
+			}
+			oldContent := orig[pathKey]
+			fileChange := FileChange{
+				Type:       ActionUpdate,
+				OldContent: &oldContent,
+				NewContent: &newContent,
+			}
+			if action.MovePath != nil {
+				fileChange.MovePath = action.MovePath
+			}
+			commit.Changes[pathKey] = fileChange
+		}
+	}
+	return commit, nil
+}
+
+func AssembleChanges(orig map[string]string, updatedFiles map[string]string) Commit {
+	commit := Commit{Changes: make(map[string]FileChange, len(updatedFiles))}
+	for p, newContent := range updatedFiles {
+		oldContent, exists := orig[p]
+		if exists && oldContent == newContent {
+			continue
+		}
+
+		if exists && newContent != "" {
+			commit.Changes[p] = FileChange{
+				Type:       ActionUpdate,
+				OldContent: &oldContent,
+				NewContent: &newContent,
+			}
+		} else if newContent != "" {
+			commit.Changes[p] = FileChange{
+				Type:       ActionAdd,
+				NewContent: &newContent,
+			}
+		} else if exists {
+			commit.Changes[p] = FileChange{
+				Type:       ActionDelete,
+				OldContent: &oldContent,
+			}
+		} else {
+			return commit // Changed from panic to simply return current commit
+		}
+	}
+	return commit
+}
+
+func LoadFiles(paths []string, openFn func(string) (string, error)) (map[string]string, error) {
+	orig := make(map[string]string, len(paths))
+	for _, p := range paths {
+		content, err := openFn(p)
+		if err != nil {
+			return nil, fileError("Open", "File not found", p)
+		}
+		orig[p] = content
+	}
+	return orig, nil
+}
+
+func ApplyCommit(commit Commit, writeFn func(string, string) error, removeFn func(string) error) error {
+	for p, change := range commit.Changes {
+		if change.Type == ActionDelete {
+			if err := removeFn(p); err != nil {
+				return err
+			}
+		} else if change.Type == ActionAdd {
+			if change.NewContent == nil {
+				return NewDiffError(fmt.Sprintf("Add action for %s has nil new_content", p))
+			}
+			if err := writeFn(p, *change.NewContent); err != nil {
+				return err
+			}
+		} else if change.Type == ActionUpdate {
+			if change.NewContent == nil {
+				return NewDiffError(fmt.Sprintf("Update action for %s has nil new_content", p))
+			}
+			if change.MovePath != nil {
+				if err := writeFn(*change.MovePath, *change.NewContent); err != nil {
+					return err
+				}
+				if err := removeFn(p); err != nil {
+					return err
+				}
+			} else {
+				if err := writeFn(p, *change.NewContent); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func ProcessPatch(text string, openFn func(string) (string, error), writeFn func(string, string) error, removeFn func(string) error) (string, error) {
+	if !strings.HasPrefix(text, "*** Begin Patch") {
+		return "", NewDiffError("Patch must start with *** Begin Patch")
+	}
+	paths := IdentifyFilesNeeded(text)
+	orig, err := LoadFiles(paths, openFn)
+	if err != nil {
+		return "", err
+	}
+
+	patch, fuzz, err := TextToPatch(text, orig)
+	if err != nil {
+		return "", err
+	}
+
+	if fuzz > 0 {
+		return "", NewDiffError(fmt.Sprintf("Patch contains fuzzy matches (fuzz level: %d)", fuzz))
+	}
+
+	commit, err := PatchToCommit(patch, orig)
+	if err != nil {
+		return "", err
+	}
+
+	if err := ApplyCommit(commit, writeFn, removeFn); err != nil {
+		return "", err
+	}
+
+	return "Patch applied successfully", nil
+}
+
+func OpenFile(p string) (string, error) {
+	data, err := os.ReadFile(p)
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
+}
+
+func WriteFile(p string, content string) error {
+	if filepath.IsAbs(p) {
+		return NewDiffError("We do not support absolute paths.")
+	}
+
+	dir := filepath.Dir(p)
+	if dir != "." {
+		if err := os.MkdirAll(dir, 0o755); err != nil {
+			return err
+		}
+	}
+
+	return os.WriteFile(p, []byte(content), 0o644)
+}
+
+func RemoveFile(p string) error {
+	return os.Remove(p)
+}
+
+func ValidatePatch(patchText string, files map[string]string) (bool, string, error) {
+	if !strings.HasPrefix(patchText, "*** Begin Patch") {
+		return false, "Patch must start with *** Begin Patch", nil
+	}
+
+	neededFiles := IdentifyFilesNeeded(patchText)
+	for _, filePath := range neededFiles {
+		if _, exists := files[filePath]; !exists {
+			return false, fmt.Sprintf("File not found: %s", filePath), nil
+		}
+	}
+
+	patch, fuzz, err := TextToPatch(patchText, files)
+	if err != nil {
+		return false, err.Error(), nil
+	}
+
+	if fuzz > 0 {
+		return false, fmt.Sprintf("Patch contains fuzzy matches (fuzz level: %d)", fuzz), nil
+	}
+
+	_, err = PatchToCommit(patch, files)
+	if err != nil {
+		return false, err.Error(), nil
+	}
+
+	return true, "Patch is valid", nil
+}