1 files changed, 428 insertions, 0 deletions
diff --git a/internal/slackware_com/changelog.go b/internal/slackware_com/changelog.go
new file mode 100644
index 0000000..90ff02b
--- /dev/null
+++ b/internal/slackware_com/changelog.go
@@ -0,0 +1,428 @@
+package slackware_com
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"strings"
+	"time"
+)
+
+const ChangeLogTxt = "ChangeLog.txt"
+
+const Break = "+--------------------------+"
+
+// The format is randomly used on Fri 01 Feb 2019 01:26:44 AM UTC.
+const AltTimeFormat = "Mon _2 Jan 2006 03:04:05 PM MST"
+
+type EntryItem interface {
+	ChangeLogEntry()
+	String() string
+}
+
+type PathUpdate interface {
+	GetPath() string
+}
+
+type EndOfLifeNotice string
+
+func (e EndOfLifeNotice) ChangeLogEntry() {
+}
+
+func (e EndOfLifeNotice) String() string {
+	return string(e)
+}
+
+type PathAdded struct {
+	Path        string
+	Description string
+}
+
+func (e *PathAdded) ChangeLogEntry() {
+}
+
+func (e *PathAdded) GetPath() string {
+	return e.Path
+}
+
+func (e *PathAdded) String() string {
+	str := fmt.Sprintf("%s:  Added.", e.Path)
+	if e.Description != "" {
+		str += "\n" + e.Description
+	}
+	return str
+}
+
+type PathRebuild struct {
+	Path        string
+	Description string
+}
+
+func (e *PathRebuild) ChangeLogEntry() {
+}
+
+func (e *PathRebuild) GetPath() string {
+	return e.Path
+}
+
+func (e *PathRebuild) String() string {
+	str := fmt.Sprintf("%s:  Rebuilt.", e.Path)
+	if e.Description != "" {
+		str += "\n" + e.Description
+	}
+	return str
+}
+
+type PathRemoved struct {
+	Path        string
+	Description string
+}
+
+func (e *PathRemoved) ChangeLogEntry() {
+}
+
+func (e *PathRemoved) GetPath() string {
+	return e.Path
+}
+
+func (e *PathRemoved) String() string {
+	str := fmt.Sprintf("%s:  Removed.", e.Path)
+	if e.Description != "" {
+		str += "\n" + e.Description
+	}
+	return str
+}
+
+type PathUpgraded struct {
+	Path        string
+	Description string
+}
+
+func (e *PathUpgraded) ChangeLogEntry() {
+}
+
+func (e *PathUpgraded) GetPath() string {
+	return e.Path
+}
+
+func (e *PathUpgraded) String() string {
+	str := fmt.Sprintf("%s:  Upgraded.", e.Path)
+	if e.Description != "" {
+		str += "\n" + e.Description
+	}
+	return str
+}
+
+type Unknown string
+
+func (e Unknown) ChangeLogEntry() {
+}
+
+func (e Unknown) String() string {
+	return string(e)
+}
+
+// Does the file path match the give path.
+//
+// Slackware's ChangeLog sometimes includes paths with '*' patterns in them,
+// for example 'patches/packages/linux-5.15.117/*:  Upgraded.'.
+func IsPathMatch(pattern string, filePath string) bool {
+	if !strings.Contains(pattern, "*") {
+		return pattern == filePath
+	}
+
+	for {
+		if pattern == "" && filePath == "" {
+			return true
+		}
+
+		pDir, pFile := path.Split(pattern)
+		dir, file := path.Split(filePath)
+
+		if pFile != "*" || pFile != file {
+			return false
+		}
+
+		pattern = pDir
+		filePath = dir
+	}
+}
+
+func FindMatches(pattern string, filePaths []string) []string {
+	var matched []string
+
+	for _, filePath := range filePaths {
+		if IsPathMatch(pattern, filePath) {
+			matched = append(matched, filePath)
+		}
+
+	}
+
+	return matched
+}
+
+func isPathUpdateLine(line string) bool {
+	_, updateType, ok := strings.Cut(line, ":")
+	if !ok {
+		return false
+	}
+
+	switch strings.TrimSpace(updateType) {
+	case "Added.",
+		"Upgraded.",
+		"Rebuilt.",
+		"Removed.":
+		return true
+	default:
+		return false
+	}
+}
+
+func addIndentation(str string) string {
+	lines := strings.Split(str, "\n")
+	for i := range lines {
+		lines[i] = "  " + lines[i]
+	}
+	return strings.Join(lines, "\n")
+}
+
+func removeIndentation(str string) string {
+	lines := strings.Split(str, "\n")
+	for i := range lines {
+		lines[i] = strings.TrimPrefix(lines[i], "  ")
+	}
+	return strings.Join(lines, "\n")
+}
+
+func ParseChangeLogEntry(arg string) EntryItem {
+	packageLine, tail, _ := strings.Cut(arg, "\n")
+
+	path, updateType, ok := strings.Cut(packageLine, ":")
+	if ok {
+		switch strings.TrimSpace(updateType) {
+		case "Added.":
+			return &PathAdded{
+				Path:        path,
+				Description: removeIndentation(tail),
+			}
+		case "Upgraded.":
+			return &PathUpgraded{
+				Path:        path,
+				Description: removeIndentation(tail),
+			}
+		case "Rebuilt.":
+			return &PathRebuild{
+				Path:        path,
+				Description: removeIndentation(tail),
+			}
+		case "Removed.":
+			return &PathRemoved{
+				Path:        path,
+				Description: removeIndentation(tail),
+			}
+		}
+	}
+
+	if strings.Contains(arg, "END OF LIFE") {
+		return EndOfLifeNotice(arg)
+	}
+
+	return Unknown(arg)
+}
+
+type Entry struct {
+	Items []EntryItem
+	Time  time.Time
+}
+
+func (d *Entry) UnmarshalText(text []byte) error {
+	date, str, ok := strings.Cut(string(text), "\n")
+	if !ok {
+		return errors.New("first line must be a date")
+	}
+
+	var err error
+	d.Time, err = time.Parse(time.UnixDate, date)
+	if err != nil {
+		unixDateErr := err
+
+		d.Time, err = time.Parse(AltTimeFormat, date)
+		if err != nil {
+			return fmt.Errorf("date line: %w", unixDateErr)
+		}
+
+	}
+
+	line, str, _ := strings.Cut(str, "\n")
+	for line != "" {
+		entryStr := line
+		for {
+			line, str, _ = strings.Cut(str, "\n")
+			if line == "" || isPathUpdateLine(line) {
+				break
+			}
+
+			entryStr += "\n" + line
+		}
+
+		item := ParseChangeLogEntry(entryStr)
+		d.Items = append(d.Items, item)
+	}
+
+	return nil
+}
+
+func (d *Entry) String() string {
+	str := d.Time.Format(time.UnixDate)
+	for _, item := range d.Items {
+		str += "\n" + addIndentation(item.String())
+	}
+	return str
+}
+
+type ChangeLog struct {
+	Entries []*Entry
+}
+
+func OpenChangeLog(filepath string) (*ChangeLog, error) {
+	f, err := os.Open(filepath)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	buf, err := io.ReadAll(f)
+	if err != nil {
+		return nil, err
+	}
+
+	var changeLog ChangeLog
+	err = changeLog.UnmarshalText(buf)
+	if err != nil {
+		return nil, err
+	}
+
+	return &changeLog, nil
+}
+
+func (c *ChangeLog) UnmarshalText(buf []byte) error {
+	buffer := bytes.NewBuffer(buf)
+	r := bufio.NewReader(buffer)
+
+mainLoop:
+	for {
+		var dayStr string
+		for {
+			line, _, err := r.ReadLine()
+			if err == io.EOF {
+				break mainLoop
+			} else if err != nil {
+				return err
+			}
+			if string(line) == Break {
+				break
+			}
+
+			if dayStr == "" {
+				dayStr = string(line)
+			} else {
+				dayStr = dayStr + "\n" + string(line)
+			}
+		}
+
+		var entry Entry
+		err := entry.UnmarshalText([]byte(dayStr))
+		if err != nil {
+			return err
+		}
+
+		c.Entries = append(c.Entries, &entry)
+	}
+
+	return nil
+}
+
+func (c *ChangeLog) First(pred func(EntryItem) bool) (*Entry, bool) {
+	for _, entry := range c.Entries {
+		for _, item := range entry.Items {
+			if pred(item) {
+				return &Entry{
+					Items: []EntryItem{item},
+					Time:  entry.Time,
+				}, true
+			}
+		}
+	}
+
+	return nil, false
+}
+
+func (c *ChangeLog) Select(pred func(EntryItem) bool) []Entry {
+	var entries []Entry
+
+	for _, entry := range c.Entries {
+		var items []EntryItem
+
+		for _, item := range entry.Items {
+			if pred(item) {
+				item := item
+				items = append(items, item)
+			}
+		}
+
+		if len(items) > 0 {
+			entries = append(entries, Entry{
+				Items: items,
+				Time:  entry.Time,
+			})
+		}
+	}
+
+	return entries
+}
+
+func GetLastInstallTime(
+	changeLog *ChangeLog,
+	installed []PackageName,
+	files []string,
+) time.Time {
+	isInstalled := make(map[string]bool)
+	for _, pkg := range installed {
+		isInstalled[pkg.String()] = true
+	}
+
+	entry, ok := changeLog.First(func(item EntryItem) bool {
+		pathItem, ok := item.(PathUpdate)
+		if !ok {
+			return false
+		}
+
+		filePaths := []string{pathItem.GetPath()}
+		if strings.Contains(filePaths[0], "*") {
+			filePaths = FindMatches(pathItem.GetPath(), files)
+		}
+
+		for _, fp := range filePaths {
+			pkg, err := NewPackageNameFromPath(fp)
+			if err != nil {
+				continue
+			}
+
+			if isInstalled[pkg.String()] {
+				return true
+			}
+		}
+
+		return false
+	})
+	if !ok {
+		return time.Time{}
+	}
+
+	return entry.Time
+
+}