1 files changed, 279 insertions, 0 deletions
diff --git a/command.go b/command.go
new file mode 100644
index 0000000..760ee25
--- /dev/null
+++ b/command.go
@@ -0,0 +1,279 @@
+package main
+
+import (
+	"errors"
+	"os"
+	"strconv"
+	"strings"
+)
+
+var (
+	ErrInvalidArgs    = errors.New("bad command arguments")
+	ErrUnknownCommand = errors.New("don't know that one")
+)
+
+type Command struct {
+	Name string
+	Args []string
+}
+
+func ParseCommand(line string) (*Command, error) {
+	line = strings.TrimSpace(line)
+	if line == "" {
+		return &Command{Name: "print"}, nil
+	}
+
+	cmd, rest, _ := strings.Cut(line, " ")
+
+	switch line[0] {
+	case 'r':
+		if strings.HasPrefix("root", cmd) {
+			return &Command{Name: "root"}, nil
+		}
+		if strings.HasPrefix("reload", cmd) {
+			return &Command{Name: "reload"}, nil
+		}
+	case 'R':
+		if strings.HasPrefix("Root", cmd) {
+			return &Command{Name: "Root"}, nil
+		}
+	case 'b':
+		if strings.HasPrefix("back", cmd) {
+			return &Command{Name: "back"}, nil
+		}
+	case 'f':
+		if strings.HasPrefix("forward", cmd) {
+			return &Command{Name: "forward"}, nil
+		}
+	case 'n':
+		if strings.HasPrefix("next", cmd) {
+			return &Command{Name: "next"}, nil
+		}
+	case 'p':
+		if strings.HasPrefix("print", cmd) {
+			return &Command{Name: "print"}, nil
+		}
+		if strings.HasPrefix("previous", cmd) {
+			return &Command{Name: "previous"}, nil
+		}
+	case 'u':
+		if strings.HasPrefix("up", cmd) {
+			return &Command{Name: "up"}, nil
+		}
+	case 'g':
+		if strings.HasPrefix("go", cmd) {
+			if rest == "" {
+				return nil, ErrInvalidArgs
+			}
+			return &Command{Name: "go", Args: []string{rest}}, nil
+		}
+	case 'h':
+		if strings.HasPrefix("help", cmd) {
+			return &Command{
+				Name: "help",
+				Args: []string{rest},
+			}, nil
+		}
+		if strings.HasPrefix("history", cmd) {
+			return &Command{Name: "history"}, nil
+		}
+	case '|':
+		return &Command{
+			Name: "pipe",
+			Args: []string{strings.TrimSpace(line[1:])},
+		}, nil
+	case 's':
+		if strings.HasPrefix("save", cmd) {
+			return &Command{
+				Name: "save",
+				Args: []string{rest},
+			}, nil
+		}
+	case 'l':
+		if strings.HasPrefix("links", cmd) {
+			return &Command{Name: "links"}, nil
+		}
+	case 'm':
+		if strings.HasPrefix("mark", cmd) {
+			args, err := parseMarkArgs(rest)
+			if err != nil {
+				return nil, err
+			}
+			return &Command{Name: "mark", Args: args}, nil
+		}
+	case 't':
+		if strings.HasPrefix("tour", cmd) {
+			args, err := parseTourArgs(rest)
+			if err != nil {
+				return nil, err
+			}
+			return &Command{Name: "tour", Args: args}, nil
+		}
+	case 'q':
+		if strings.HasPrefix("quit", cmd) {
+			return &Command{Name: "quit"}, nil
+		}
+	}
+
+	if rest == "" {
+		return &Command{Name: "go", Args: []string{cmd}}, nil
+	}
+
+	return nil, ErrUnknownCommand
+}
+
+func parseMarkArgs(line string) ([]string, error) {
+	if line == "" {
+		return nil, ErrInvalidArgs
+	}
+
+	fields := strings.Fields(line)
+	switch fields[0][0] {
+	case 'a':
+		if strings.HasPrefix("add", fields[0]) {
+			fields[0] = "add"
+			if len(fields) != 3 {
+				return nil, ErrInvalidArgs
+			}
+			return fields, nil
+		}
+	case 'g':
+		if strings.HasPrefix("go", fields[0]) {
+			fields[0] = "go"
+			if len(fields) != 2 {
+				return nil, ErrInvalidArgs
+			}
+			return fields, nil
+		}
+	case 'l':
+		if strings.HasPrefix("list", fields[0]) {
+			fields[0] = "list"
+			if len(fields) != 1 {
+				return nil, ErrInvalidArgs
+			}
+			return fields, nil
+		}
+	}
+
+	if len(fields) != 1 {
+		return nil, ErrInvalidArgs
+	}
+
+	return []string{"go", fields[0]}, nil
+}
+
+func parseTourArgs(line string) ([]string, error) {
+	if line == "" {
+		return []string{"next"}, nil
+	}
+
+	fields := strings.Fields(line)
+	switch fields[0][0] {
+	case 'a':
+		if strings.HasPrefix("add", fields[0]) {
+			fields[0] = "add"
+			if len(fields) == 1 {
+				return nil, ErrInvalidArgs
+			}
+			if strings.HasPrefix("next", fields[1]) {
+				fields[1] = "next"
+			}
+			return fields, nil
+		}
+	case 'n':
+		if strings.HasPrefix("next", fields[0]) {
+			fields[0] = "next"
+			if len(fields) != 1 {
+				return nil, ErrInvalidArgs
+			}
+			return fields, nil
+		}
+	case 's':
+		if strings.HasPrefix("set", fields[0]) {
+			fields[0] = "set"
+			if len(fields) == 1 {
+				return fields, nil
+			}
+			if len(fields) != 2 {
+				return nil, ErrInvalidArgs
+			}
+			if len(fields[1]) != 1 || fields[1][0] < 'a' || fields[1][0] > 'z' {
+				return nil, ErrInvalidArgs
+			}
+			return fields, nil
+		}
+		if strings.HasPrefix("show", fields[0]) {
+			fields[0] = "show"
+			if len(fields) != 1 {
+				return nil, ErrInvalidArgs
+			}
+			return fields, nil
+		}
+	case 'l':
+		if strings.HasPrefix("list", fields[0]) {
+			fields[0] = "list"
+			if len(fields) != 1 {
+				return nil, ErrInvalidArgs
+			}
+			return fields, nil
+		}
+	case 'p':
+		if strings.HasPrefix("previous", fields[0]) {
+			fields[0] = "previous"
+			if len(fields) != 1 {
+				return nil, ErrInvalidArgs
+			}
+			return fields, nil
+		}
+	case 'g':
+		if strings.HasPrefix("go", fields[0]) {
+			fields[0] = "go"
+			if len(fields) != 2 {
+				return nil, ErrInvalidArgs
+			}
+			if _, err := strconv.Atoi(fields[1]); err != nil {
+				return nil, ErrInvalidArgs
+			}
+			return fields, nil
+		}
+	}
+
+	return nil, ErrInvalidArgs
+}
+
+func RunCommand(conf *Config, cmd *Command, state *BrowserState) error {
+	switch cmd.Name {
+	case "root":
+		return Root(state, true, conf)
+	case "Root":
+		return Root(state, false, conf)
+	case "reload":
+		return Reload(state, conf)
+	case "back":
+		return Back(state)
+	case "forward":
+		return Forward(state)
+	case "next":
+		return Next(state, conf)
+	case "previous":
+		return Previous(state, conf)
+	case "up":
+		return Up(state, conf)
+	case "go":
+		return Go(state, cmd.Args[0], conf)
+	case "print":
+		return Print(state)
+	case "links":
+		return Links(state, conf)
+	case "history":
+		return HistoryCmd(state)
+	case "save":
+		return Save(state, cmd.Args[0], conf)
+	case "mark":
+		return Mark(state, cmd.Args, conf)
+	case "quit":
+		os.Exit(0)
+	}
+
+	return ErrUnknownCommand
+}