import Foundation

/// Parameters for creating a new post.
public struct NewPostOptions: Sendable {

    public enum Visibility: String, Sendable {
        case `public`
        case mention
    }

    public var text: String
    public var lang: String?
    public var tags: String?
    /// Full post URL to reply to: `"https://feed.url/social.org#TIMESTAMP"`.
    public var replyTo: String?
    /// Full post URL to boost: `"https://feed.url/social.org#TIMESTAMP"`.
    public var include: String?
    /// Emoji or short text reaction. Combined with `replyTo` and empty `text` = reaction post.
    public var mood: String?
    /// Group in `"Name https://relay.url"` format.
    public var group: String?
    public var visibility: Visibility?
    public var client: String

    /// Poll close date. Body must contain `- [ ] Option` lines. Written as `:POLL_END:`.
    public var pollEnd: Date?
    /// The option text chosen when voting on a poll. Combined with `replyTo`. Written as `:POLL_OPTION:`.
    public var pollOption: String?
    /// Account migration in `"old-url new-url"` format. Written as `:MIGRATION:`.
    public var migration: String?

    public init(
        text: String,
        lang: String? = nil,
        tags: String? = nil,
        replyTo: String? = nil,
        include: String? = nil,
        mood: String? = nil,
        group: String? = nil,
        visibility: Visibility? = nil,
        client: String = "iOS",
        pollEnd: Date? = nil,
        pollOption: String? = nil,
        migration: String? = nil
    ) {
        self.text = text
        self.lang = lang
        self.tags = tags
        self.replyTo = replyTo
        self.include = include
        self.mood = mood
        self.group = group
        self.visibility = visibility
        self.client = client
        self.pollEnd = pollEnd
        self.pollOption = pollOption
        self.migration = migration
    }

    // MARK: - Factories

    /// Reaction post: `REPLY_TO` + `MOOD`, no body text.
    public static func reaction(to postURL: String, mood: String) -> NewPostOptions {
        NewPostOptions(text: "", replyTo: postURL, mood: mood)
    }

    /// Boost post: `INCLUDE` pointing to the boosted post URL.
    /// `commentary` is optional body text (quote-boost).
    public static func boost(of postURL: String, commentary: String = "") -> NewPostOptions {
        NewPostOptions(text: commentary, include: postURL)
    }

    /// Poll post: checkboxes in body, `POLL_END` property.
    ///
    /// - Parameters:
    ///   - question: Optional introductory text above the options.
    ///   - options: Non-empty list of poll option strings.
    ///   - end: Poll close date.
    ///   - lang: Optional `:LANG:`.
    ///   - tags: Optional `:TAGS:`.
    ///   - mood: Optional `:MOOD:`.
    ///   - visibility: Optional `:VISIBILITY:` (`.public` is implicit).
    public static func poll(
        question: String = "",
        options: [String],
        end: Date,
        lang: String? = nil,
        tags: String? = nil,
        mood: String? = nil,
        visibility: Visibility? = nil
    ) -> NewPostOptions {
        let checkboxes = options.map { "- [ ] \($0)" }.joined(separator: "\n")
        // Org Mode requires a blank line between a paragraph and a list
        // for the list to be recognised; without it Emacs renders the
        // checkboxes as a single wrapped line.
        let body = question.isEmpty ? checkboxes : "\(question)\n\n\(checkboxes)"
        return NewPostOptions(
            text: body,
            lang: lang,
            tags: tags,
            mood: mood,
            visibility: visibility,
            pollEnd: end
        )
    }

    /// Poll vote: `REPLY_TO` + `POLL_OPTION`.
    ///
    /// - Parameters:
    ///   - option: The exact option text being voted for.
    ///   - pollURL: Canonical URL of the poll post (`feed#timestamp`).
    public static func vote(for option: String, on pollURL: String) -> NewPostOptions {
        NewPostOptions(text: "", replyTo: pollURL, pollOption: option)
    }

    /// Account migration post: `MIGRATION: old-url new-url`.
    public static func migration(from oldURL: String, to newURL: String) -> NewPostOptions {
        NewPostOptions(text: "", migration: "\(oldURL) \(newURL)")
    }
}