SearchCondition.cs

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Text;

namespace S22.Imap {
	/// <summary>
	/// Chainable search conditions to be used with the Search method.
	/// </summary>
	public class SearchCondition {
		/// <summary>
		/// Finds all messages in the mailbox.
		/// </summary>
		/// <returns>A SearchCondition object representing the "all" search criterion</returns>
		public static SearchCondition All() {
			return new SearchCondition { Field = Fields.All };
		}
		/// <summary>
		/// Finds messages that contain the specified string in the header or body of the
		/// message.
		/// </summary>
		/// <param name="text">String to search messages for</param>
		/// <returns>A SearchCondition object representing the "text" search criterion</returns>
		public static SearchCondition Text(string text) {
			return new SearchCondition { Field = Fields.Text, Value = text };
		}
		/// <summary>
		/// Finds messages that contain the specified string in the envelope structure's
		/// BCC field.
		/// </summary>
		/// <param name="text">String to search the envelope structure's BCC field for</param>
		/// <returns>A SearchCondition object representing the "BCC" search criterion</returns>
		public static SearchCondition BCC(string text) {
			return new SearchCondition { Field = Fields.BCC, Value = text };
		}
		/// <summary>
		/// Finds messages whose internal date (disregarding time and timezone) is
		/// earlier than the specified date.
		/// </summary>
		/// <param name="date">Date to compare the message's internal date with</param>
		/// <returns>A SearchCondition object representing the "Before" search criterion</returns>
		public static SearchCondition Before(DateTime date) {
			return new SearchCondition { Field = Fields.Before, Value = date };
		}
		/// <summary>
		/// Finds messages that contain the specified string in the body of the
		/// message.
		/// </summary>
		/// <param name="text">String to search the message body for</param>
		/// <returns>A SearchCondition object representing the "Body" search criterion</returns>
		public static SearchCondition Body(string text) {
			return new SearchCondition { Field = Fields.Body, Value = text };
		}
		/// <summary>
		/// Finds messages that contain the specified string in the envelope structure's
		/// CC field.
		/// </summary>
		/// <param name="text">String to search the envelope structure's CC field for</param>
		/// <returns>A SearchCondition object representing the "CC" search criterion</returns>
		public static SearchCondition Cc(string text) {
			return new SearchCondition { Field = Fields.Cc, Value = text };
		}
		/// <summary>
		/// Finds messages that contain the specified string in the envelope structure's
		/// FROM field.
		/// </summary>
		/// <param name="text">String to search the envelope structure's FROM field for</param>
		/// <returns>A SearchCondition object representing the "FROM" search criterion</returns>
		public static SearchCondition From(string text) {
			return new SearchCondition { Field = Fields.From, Value = text };
		}
		/// <summary>
		/// Finds messages that have a header with the specified field-name and that
		/// contains the specified string in the text of the header.
		/// </summary>
		/// <param name="name">field-name of the header to search for</param>
		/// <param name="text">String to search for in the text of the header</param>
		/// <returns>A SearchCondition object representing the "HEADER" search
		/// criterion</returns>
		/// <remarks>
		/// If the string to search is zero-length, this matches all messages
		/// that have a header line with the specified field-name regardless of the
		/// contents.
		/// </remarks>
		public static SearchCondition Header(string name, string text) {
			return new SearchCondition { Field = Fields.Header,
				Value = name + " " + text.QuoteString() };
		}
		/// <summary>
		/// Finds messages with the specified keyword flag set.
		/// </summary>
		/// <param name="text">Keyword flag to search for</param>
		/// <returns>A SearchCondition object representing the "KEYWORD" search
		/// criterion</returns>
		public static SearchCondition Keyword(string text) {
			return new SearchCondition { Field = Fields.Keyword, Value = text };
		}
		/// <summary>
		/// Finds messages with a size larger than the specified number of bytes.
		/// </summary>
		/// <param name="size">Minimum size, in bytes a message must have to be
		/// included in the result set</param>
		/// <returns>A SearchCondition object representing the "LARGER" search
		/// criterion</returns>
		public static SearchCondition Larger(long size) {
			return new SearchCondition { Field = Fields.Larger, Value = size };
		}
		/// <summary>
		/// Finds messages with a size smaller than the specified number of bytes.
		/// </summary>
		/// <param name="size">Maximum size, in bytes a message must have to be
		/// included in the result set</param>
		/// <returns>A SearchCondition object representing the "SMALLER" search
		/// criterion</returns>
		public static SearchCondition Smaller(long size) {
			return new SearchCondition { Field = Fields.Smaller, Value = size };
		}
		/// <summary>
		/// Finds messages whose Date: header (disregarding time and timezone) is
		/// earlier than the specified date.
		/// </summary>
		/// <param name="date">Date to compare the Date: header field with.</param>
		/// <returns>A SearchCondition object representing the "SENTBEFORE" search
		/// criterion</returns>
		public static SearchCondition SentBefore(DateTime date) {
			return new SearchCondition { Field = Fields.SentBefore, Value = date };
		}
		/// <summary>
		/// Finds messages whose Date: header (disregarding time and timezone) is
		/// within the specified date.
		/// </summary>
		/// <param name="date">Date to compare the Date: header field with.</param>
		/// <returns>A SearchCondition object representing the "SENTON" search
		/// criterion</returns>
		public static SearchCondition SentOn(DateTime date) {
			return new SearchCondition { Field = Fields.SentOn, Value = date };
		}
		/// <summary>
		/// Finds messages whose Date: header (disregarding time and timezone) is
		/// within or later than the specified date.
		/// </summary>
		/// <param name="date">Date to compare the Date: header field with.</param>
		/// <returns>A SearchCondition object representing the "SENTSINCE" search
		/// criterion</returns>
		public static SearchCondition SentSince(DateTime date) {
			return new SearchCondition { Field = Fields.SentSince, Value = date };
		}
		/// <summary>
		/// Finds messages that contain the specified string in the envelope
		/// structure's SUBJECT field.
		/// </summary>
		/// <param name="text">String to search the envelope structure's SUBJECT
		/// field for</param>
		/// <returns>A SearchCondition object representing the "SUBJECT" search
		/// criterion</returns>
		public static SearchCondition Subject(string text) {
			return new SearchCondition { Field = Fields.Subject, Value = text };
		}
		/// <summary>
		/// Finds messages that contain the specified string in the envelope
		/// structure's TO field.
		/// </summary>
		/// <param name="text">String to search the envelope structure's TO
		/// field for</param>
		/// <returns>A SearchCondition object representing the "TO" search
		/// criterion</returns>
		public static SearchCondition To(string text) {
			return new SearchCondition { Field = Fields.To, Value = text };
		}
		/// <summary>
		/// Finds messages with unique identifiers corresponding to the specified
		/// unique identifier set.
		/// </summary>
		/// <param name="uids">An array of unique identifiers</param>
		/// <returns>A SearchCondition object representing the "UID" search
		/// criterion</returns>
		public static SearchCondition UID(params uint[] uids) {
			return new SearchCondition { Field = Fields.UID,
				Value = uids };
		}
		/// <summary>
		/// Finds messages with a unique identifier greater than the specified
		/// unique identifier. Because of the nature of the IMAP search mechanism,
		/// the result set will always contain the UID of the last message in the
		/// mailbox, even if said UID is smaller than the UID specified.
		/// </summary>
		/// <param name="uid">A unique identifier (UID).</param>
		/// <returns>A SearchCondition object representing the "UID" search
		/// criterion</returns>
		public static SearchCondition GreaterThan(uint uid) {
			return new SearchCondition { Field = Fields.UID,
				Value = (uid + 1).ToString() + ":*", Quote = false };
		}
		/// <summary>
		/// Finds messages with a unique identifier less than the specified
		/// unique identifier.
		/// </summary>
		/// <param name="uid">A unique identifier (UID).</param>
		/// <returns>A SearchCondition object representing the "UID" search
		/// criterion</returns>
		public static SearchCondition LessThan(uint uid) {
			return new SearchCondition { Field = Fields.UID,
				Value = "1:" + (uid - 1).ToString(), Quote = false };
		}
		/// <summary>
		/// Finds messages that do not have the specified keyword flag set.
		/// </summary>
		/// <param name="text">A valid IMAP keyword flag</param>
		/// <returns>A SearchCondition object representing the "UNKEYWORD"
		/// search criterion</returns>
		public static SearchCondition Unkeyword(string text) {
			return new SearchCondition { Field = Fields.Unkeyword, Value = text };
		}
		/// <summary>
		/// Finds messages with the \Answered flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "ANSWERED" search
		/// criterion</returns>
		public static SearchCondition Answered() {
			return new SearchCondition { Field = Fields.Answered };
		}
		/// <summary>
		/// Finds messages with the \Deleted flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "DELETED" search
		/// criterion</returns>
		public static SearchCondition Deleted() {
			return new SearchCondition { Field = Fields.Deleted };
		}
		/// <summary>
		/// Finds messages with the \Draft flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "DRAFT" search
		/// criterion</returns>
		public static SearchCondition Draft() {
			return new SearchCondition { Field = Fields.Draft };
		}
		/// <summary>
		/// Finds messages with the \Flagged flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "FLAGGED" search
		/// criterion</returns>
		public static SearchCondition Flagged() {
			return new SearchCondition { Field = Fields.Flagged };
		}
		/// <summary>
		/// Finds messages that have the \Recent flag set but not the \Seen flag.
		/// </summary>
		/// <returns>A SearchCondition object representing the "NEW" search
		/// criterion</returns>
		public static SearchCondition New() {
			return new SearchCondition { Field = Fields.New };
		}
		/// <summary>
		/// Finds messages that do not have the \Recent flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "OLD" search
		/// criterion</returns>
		public static SearchCondition Old() {
			return new SearchCondition { Field = Fields.Old };
		}
		/// <summary>
		/// Finds messages that have the \Recent flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "RECENT" search
		/// criterion</returns>
		public static SearchCondition Recent() {
			return new SearchCondition { Field = Fields.Recent };
		}
		/// <summary>
		/// Finds messages that have the \Seen flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "SEEN" search
		/// criterion</returns>
		public static SearchCondition Seen() {
			return new SearchCondition { Field = Fields.Seen };
		}
		/// <summary>
		/// Finds messages that do not have the \Answered flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "UNANSWERED" search
		/// criterion</returns>
		public static SearchCondition Unanswered() {
			return new SearchCondition { Field = Fields.Unanswered };
		}
		/// <summary>
		/// Finds messages that do not have the \Deleted flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "UNDELETED" search
		/// criterion</returns>
		public static SearchCondition Undeleted() {
			return new SearchCondition { Field = Fields.Undeleted };
		}
		/// <summary>
		/// Finds messages that do not have the \Draft flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "UNDRAFT" search
		/// criterion</returns>
		public static SearchCondition Undraft() {
			return new SearchCondition { Field = Fields.Undraft };
		}
		/// <summary>
		/// Finds messages that do not have the \Flagged flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "UNFLAGGED" search
		/// criterion</returns>
		public static SearchCondition Unflagged() {
			return new SearchCondition { Field = Fields.Unflagged };
		}
		/// <summary>
		/// Finds messages that do not have the \Seen flag set.
		/// </summary>
		/// <returns>A SearchCondition object representing the "UNSEEN" search
		/// criterion</returns>
		public static SearchCondition Unseen() {
			return new SearchCondition { Field = Fields.Unseen };
		}

		/// <summary>
		/// Logically ANDs multiple search conditions, meaning a message will only
		/// be included in the search result set if all conditions are met.
		/// </summary>
		/// <param name="other">A search condition to logically AND this
		/// SearchCondition instance with</param>
		/// <returns>A new SearchCondition instance which can be further chained
		/// with other search conditions.</returns>
		public SearchCondition And(SearchCondition other) {
			return Join(string.Empty, this, other);
		}

		/// <summary>
		/// Logically negates search conditions, meaning a message will only
		/// be included in the search result set if the specified conditions
		/// are not met.
		/// </summary>
		/// <param name="other">A search condition that must not be met by a
		/// message for it to be included in the search result set</param>
		/// <returns>A new SearchCondition instance which can be further chained
		/// with other search conditions.</returns>
		public SearchCondition Not(SearchCondition other) {
			return Join("NOT", this, other);
		}

		/// <summary>
		/// Logically ORs multiple search conditions, meaning a message will be
		/// included in the search result set if it meets at least one of the
		/// conditions.
		/// </summary>
		/// <param name="other">A search condition to logically OR this
		/// SearchCondition instance with</param>
		/// <returns>A new SearchCondition instance which can be further chained
		/// with other search conditions.</returns>
		public SearchCondition Or(SearchCondition other) {
			return Join("OR", this, other);
		}

		/// <summary>
		/// The search keys which can be used with the IMAP SEARCH command, as
		/// are defined in section 6.4.4 of RFC 3501.
		/// </summary>
		private enum Fields {
			BCC, Before, Body, Cc, From, Header, Keyword,
			Larger, On, SentBefore, SentOn, SentSince, Since, Smaller, Subject,
			Text, To, UID, Unkeyword, All, Answered, Deleted, Draft, Flagged,
			New, Old, Recent, Seen, Unanswered, Undeleted, Undraft, Unflagged, Unseen
		}

		private object Value { get; set; }
		private Fields? Field { get; set; }
		private List<SearchCondition> Conditions { get; set; }
		private string Operator { get; set; }
		private bool Quote = true;

		/// <summary>
		/// Joins two SearchCondition objects into a new one using the specified
		/// logical operator.
		/// </summary>
		/// <param name="condition">The logical operator to use for joining the
		/// search conditions. Possible values are "OR", "NOT" and the empty
		/// string "" which denotes a logical AND.</param>
		/// <param name="left">The first SearchCondition object</param>
		/// <param name="right">The second SearchCondition object</param>
		/// <returns>A new SearchCondition object representing the two
		/// search conditions joined by the specified logical operator.</returns>
		private static SearchCondition Join(string condition, SearchCondition left,
			SearchCondition right) {
			return new SearchCondition {
				Operator = condition.ToUpper(),
				Conditions = new List<SearchCondition> { left, right }
			};
		}

		/// <summary>
		/// Constructs a string from this SearchCondition object using the proper syntax
		/// as is required for the IMAP SEARCH command.
		/// </summary>
		/// <returns>A string representing this SearchCondition instance that can be
		/// used with the IMAP SEARCH command.</returns>
		public override string ToString() {
			if (Conditions != null && Conditions.Count > 0 && Operator != null) {
				return (Operator.ToUpper() + " (" +
					string.Join(") (", Conditions) + ")").Trim();
			}
			StringBuilder builder = new StringBuilder();
			if (Field != null)
				builder.Append(Field.ToString().ToUpper());
			object Val = Value;
			if (Val != null) {
				if (Field != null)
					builder.Append(" ");
				if (Val is string) {
					string s = (string)Val;
					// If the string contains non-ASCII characters we must use the somewhat
					// cumbersome literal form as is outlined in RFC 3501 Section 4.3.
					if (!s.IsASCII()) {
						builder.AppendLine("{" + Encoding.UTF8.GetBytes(s).Length + "}");
					} else {
						if (Quote)
							Val = ((string)Val).QuoteString();
					}
				} else if (Val is DateTime) {
					Val = ((DateTime)Val).ToString("dd-MMM-yyyy",
						CultureInfo.InvariantCulture).QuoteString();
				} else if (Val is uint[]) {
					Val = string.Join<uint>(",", (uint[])Val);
				}
				builder.Append(Val);
			}
			return builder.ToString();
		}
	}
}