import Foundation
import Observation
import OrgSocialKit

@Observable @MainActor
final class EditProfileViewModel {

    var nick = ""
    var title = ""
    var description = ""
    var avatar = ""
    var location = ""
    var birthday = ""
    var language = ""
    var linksText = ""
    var contactsText = ""

    var isSaving = false
    var errorMessage: String?
    var saved = false

    private let pw = ProfileWriter()

    var isLoading = false

    init() { loadFromUserDefaults() }

    func load() async {
        guard let url = ownFeedURL else { return }
        isLoading = true
        defer { isLoading = false }
        // bypassCache so the edit form reflects the real feed, not a stale CDN copy.
        guard let content = try? await FeedFetcher().fetch(from: url, bypassCache: true) else { return }
        loadFromContent(content)
    }

    func save() async {
        guard let feedURL = ownFeedURL, let uploader = makeUploader() else {
            errorMessage = "Configure your feed in Settings before editing your profile."
            return
        }
        isSaving = true
        errorMessage = nil
        defer { isSaving = false }

        do {
            // bypassCache so we patch the latest authoritative content, not a stale cache.
            var content = try await FeedFetcher().fetch(from: feedURL, bypassCache: true)

            content = pw.setKeyword("NICK",        value: nick,        in: content)
            content = pw.setKeyword("TITLE",       value: title,       in: content)
            if description.isEmpty {
                content = pw.removeKeyword("DESCRIPTION", from: content)
            } else {
                content = pw.setKeyword("DESCRIPTION", value: description, in: content)
            }
            if avatar.isEmpty {
                content = pw.removeKeyword("AVATAR", from: content)
            } else {
                content = pw.setKeyword("AVATAR", value: avatar, in: content)
            }
            if location.isEmpty {
                content = pw.removeKeyword("LOCATION", from: content)
            } else {
                content = pw.setKeyword("LOCATION", value: location, in: content)
            }
            if birthday.isEmpty {
                content = pw.removeKeyword("BIRTHDAY", from: content)
            } else {
                content = pw.setKeyword("BIRTHDAY", value: birthday, in: content)
            }
            if language.isEmpty {
                content = pw.removeKeyword("LANGUAGE", from: content)
            } else {
                content = pw.setKeyword("LANGUAGE", value: language, in: content)
            }

            let links = linksText.components(separatedBy: "\n").map { $0.trimmingCharacters(in: .whitespaces) }.filter { !$0.isEmpty }
            content = pw.setMultiKeyword("LINK", values: links, in: content)

            let contacts = contactsText.components(separatedBy: "\n").map { $0.trimmingCharacters(in: .whitespaces) }.filter { !$0.isEmpty }
            content = pw.setMultiKeyword("CONTACT", values: contacts, in: content)

            try await uploader.upload(content: content)
            FollowCoordinator.shared.updateCachedContent(content)
            saved = true
        } catch {
            errorMessage = error.localizedDescription
        }
    }

    // MARK: - Private helpers

    private func loadFromUserDefaults() {
        nick = UserDefaults.standard.string(forKey: "nick") ?? ""
    }

    private func loadFromContent(_ content: String) {
        // Quick parse: read header keyword values
        for line in content.components(separatedBy: "\n") {
            let t = line.trimmingCharacters(in: .whitespaces)
            if t == "* Posts" { break }
            guard t.hasPrefix("#+"), let colonIdx = t.firstIndex(of: ":") else { continue }
            let kw = String(t[t.index(t.startIndex, offsetBy: 2)..<colonIdx]).uppercased()
            let val = String(t[t.index(after: colonIdx)...]).trimmingCharacters(in: .whitespaces)
            switch kw {
            case "NICK":        nick = val
            case "TITLE":       title = val
            case "DESCRIPTION": description = val
            case "AVATAR":      avatar = val
            case "LOCATION":    location = val
            case "BIRTHDAY":    birthday = val
            case "LANGUAGE":    language = val
            case "LINK":        linksText += (linksText.isEmpty ? "" : "\n") + val
            case "CONTACT":     contactsText += (contactsText.isEmpty ? "" : "\n") + val
            default: break
            }
        }
    }

    private var ownFeedURL: URL? {
        guard let raw = UserDefaults.standard.string(forKey: "publicFeedURL"),
              let url = URL(string: raw), url.scheme?.hasPrefix("http") == true else { return nil }
        return url
    }

    private func makeUploader() -> (any FeedUploader)? { UploaderFactory.makeUploader() }
}