package imap

import "strings"

// tokenize splits an IMAP command line into space-separated tokens, treating
// "quoted strings" and (parenthesized lists) as single tokens (lists keep
// their outer parens so command handlers can recognize and further split
// them). Literal syntax ({n}\r\n<bytes>) is not handled here — see session.go's
// readCommand, which handles literals as a pre-pass before tokenizing since
// they require reading raw bytes off the connection, not just string scanning.
func tokenize(line string) []string {
	var tokens []string
	i, n := 0, len(line)

	for i < n {
		for i < n && (line[i] == ' ' || line[i] == '\t') {
			i++
		}
		if i >= n {
			break
		}

		switch line[i] {
		case '"':
			j := i + 1
			var sb strings.Builder
			for j < n && line[j] != '"' {
				if line[j] == '\\' && j+1 < n {
					j++
				}
				sb.WriteByte(line[j])
				j++
			}
			tokens = append(tokens, sb.String())
			i = j + 1

		case '(':
			depth := 1
			j := i + 1
			for j < n && depth > 0 {
				switch line[j] {
				case '(':
					depth++
				case ')':
					depth--
				}
				j++
			}
			tokens = append(tokens, line[i:j])
			i = j

		default:
			j := i
			for j < n && line[j] != ' ' && line[j] != '\t' {
				j++
			}
			tokens = append(tokens, line[i:j])
			i = j
		}
	}
	return tokens
}

// splitList takes a token like "(FLAGS UID)" and returns its inner
// space-separated items — used by FETCH/STORE argument parsing.
func splitList(token string) []string {
	inner := strings.TrimPrefix(token, "(")
	inner = strings.TrimSuffix(inner, ")")
	if inner == "" {
		return nil
	}
	return tokenize(inner)
}

func isList(token string) bool {
	return strings.HasPrefix(token, "(") && strings.HasSuffix(token, ")")
}