Feat: minimize top commands agent-clip style

tools/chain.go

@@ -0,0 +1,271 @@
+package tools
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+// Operator represents a chain operator between commands.
+type Operator int
+
+const (
+	OpNone Operator = iota
+	OpAnd           // &&
+	OpOr            // ||
+	OpSeq           // ;
+	OpPipe          // |
+)
+
+// Segment is a single command in a chain.
+type Segment struct {
+	Raw string
+	Op  Operator // operator AFTER this segment
+}
+
+// ParseChain splits a command string into segments by &&, ;, and |.
+// Respects quoted strings (single and double quotes).
+func ParseChain(input string) []Segment {
+	var segments []Segment
+	var current strings.Builder
+	runes := []rune(input)
+	n := len(runes)
+
+	for i := 0; i < n; i++ {
+		ch := runes[i]
+
+		// handle quotes
+		if ch == '\'' || ch == '"' {
+			quote := ch
+			current.WriteRune(ch)
+			i++
+			for i < n && runes[i] != quote {
+				current.WriteRune(runes[i])
+				i++
+			}
+			if i < n {
+				current.WriteRune(runes[i])
+			}
+			continue
+		}
+
+		// &&
+		if ch == '&' && i+1 < n && runes[i+1] == '&' {
+			segments = append(segments, Segment{
+				Raw: strings.TrimSpace(current.String()),
+				Op:  OpAnd,
+			})
+			current.Reset()
+			i++ // skip second &
+			continue
+		}
+
+		// ;
+		if ch == ';' {
+			segments = append(segments, Segment{
+				Raw: strings.TrimSpace(current.String()),
+				Op:  OpSeq,
+			})
+			current.Reset()
+			continue
+		}
+
+		// ||
+		if ch == '|' && i+1 < n && runes[i+1] == '|' {
+			segments = append(segments, Segment{
+				Raw: strings.TrimSpace(current.String()),
+				Op:  OpOr,
+			})
+			current.Reset()
+			i++ // skip second |
+			continue
+		}
+
+		// | (single pipe)
+		if ch == '|' {
+			segments = append(segments, Segment{
+				Raw: strings.TrimSpace(current.String()),
+				Op:  OpPipe,
+			})
+			current.Reset()
+			continue
+		}
+
+		current.WriteRune(ch)
+	}
+
+	// last segment
+	last := strings.TrimSpace(current.String())
+	if last != "" {
+		segments = append(segments, Segment{Raw: last, Op: OpNone})
+	}
+
+	return segments
+}
+
+// ExecChain executes a command string with pipe/chaining support.
+// Returns the combined output of all commands.
+func ExecChain(command string) string {
+	segments := ParseChain(command)
+	if len(segments) == 0 {
+		return "[error] empty command"
+	}
+
+	var collected []string
+	var lastOutput string
+	var lastErr error
+	pipeInput := ""
+
+	for i, seg := range segments {
+		if i > 0 {
+			prevOp := segments[i-1].Op
+			// && semantics: skip if previous failed
+			if prevOp == OpAnd && lastErr != nil {
+				continue
+			}
+			// || semantics: skip if previous succeeded
+			if prevOp == OpOr && lastErr == nil {
+				continue
+			}
+		}
+
+		// determine stdin for this segment
+		segStdin := ""
+		if i == 0 {
+			segStdin = pipeInput
+		} else if segments[i-1].Op == OpPipe {
+			segStdin = lastOutput
+		}
+
+		lastOutput, lastErr = execSingle(seg.Raw, segStdin)
+
+		// pipe: output flows to next command's stdin
+		// && or ;: collect output
+		if i < len(segments)-1 && seg.Op == OpPipe {
+			continue
+		}
+		if lastOutput != "" {
+			collected = append(collected, lastOutput)
+		}
+	}
+
+	return strings.Join(collected, "\n")
+}
+
+// execSingle executes a single command (with arguments) and returns output and error.
+func execSingle(command, stdin string) (string, error) {
+	parts := tokenize(command)
+	if len(parts) == 0 {
+		return "", fmt.Errorf("empty command")
+	}
+
+	name := parts[0]
+	args := parts[1:]
+
+	// Check if it's a built-in Go command
+	if result := execBuiltin(name, args, stdin); result != "" {
+		return result, nil
+	}
+
+	// Otherwise execute as system command
+	cmd := exec.Command(name, args...)
+	if stdin != "" {
+		cmd.Stdin = strings.NewReader(stdin)
+	}
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		return string(output), err
+	}
+	return string(output), nil
+}
+
+// tokenize splits a command string by whitespace, respecting quotes.
+func tokenize(input string) []string {
+	var tokens []string
+	var current strings.Builder
+	inQuote := false
+	var quoteChar rune
+
+	for _, ch := range input {
+		if inQuote {
+			if ch == quoteChar {
+				inQuote = false
+			} else {
+				current.WriteRune(ch)
+			}
+			continue
+		}
+
+		if ch == '\'' || ch == '"' {
+			inQuote = true
+			quoteChar = ch
+			continue
+		}
+
+		if ch == ' ' || ch == '\t' {
+			if current.Len() > 0 {
+				tokens = append(tokens, current.String())
+				current.Reset()
+			}
+			continue
+		}
+
+		current.WriteRune(ch)
+	}
+
+	if current.Len() > 0 {
+		tokens = append(tokens, current.String())
+	}
+
+	return tokens
+}
+
+// execBuiltin executes a built-in command if it exists.
+func execBuiltin(name string, args []string, stdin string) string {
+	switch name {
+	case "echo":
+		if stdin != "" {
+			return stdin
+		}
+		return strings.Join(args, " ")
+	case "time":
+		return "2006-01-02 15:04:05 MST"
+	case "cat":
+		if len(args) == 0 {
+			if stdin != "" {
+				return stdin
+			}
+			return ""
+		}
+		data, err := os.ReadFile(args[0])
+		if err != nil {
+			return fmt.Sprintf("[error] cat: %v", err)
+		}
+		return string(data)
+	case "pwd":
+		return fsRootDir
+	case "cd":
+		if len(args) == 0 {
+			return "[error] usage: cd <dir>"
+		}
+		dir := args[0]
+		// Resolve relative to fsRootDir
+		abs := dir
+		if !filepath.IsAbs(dir) {
+			abs = filepath.Join(fsRootDir, dir)
+		}
+		abs = filepath.Clean(abs)
+		info, err := os.Stat(abs)
+		if err != nil {
+			return fmt.Sprintf("[error] cd: %v", err)
+		}
+		if !info.IsDir() {
+			return fmt.Sprintf("[error] cd: not a directory: %s", dir)
+		}
+		fsRootDir = abs
+		return fmt.Sprintf("Changed directory to: %s", fsRootDir)
+	}
+	return ""
+}