//
//  DirectorySearch.swift
//  SimpleX
//
//  Created by spaced4ndy on 12.08.2026.
//  Copyright © 2026 SimpleX Chat. All rights reserved.
//

import Foundation
import SimpleXChat

// The directory's address, as published in docs/DIRECTORY.md. It must be the short link form -
// only that one carries the keys a service request needs; a full link fails every time.
let DIRECTORY_SERVICE_LINK = "https://smp4.simplex.im/a#lXUjJW5vHYQzoLYgmi8GbxkGP41_kjefFvBrdwg-0Ok"

// A search sets up an encrypted connection, so it takes seconds, not milliseconds.
let DIRECTORY_SEARCH_TIMEOUT_SEC: Double = 10

struct DirectoryPublicLink: Decodable, Hashable {
    var connFullLink: String? = nil
    var connShortLink: String? = nil
}

struct DirectoryEntryType: Decodable, Hashable {
    var groupType: GroupType? = nil
    var summary: GroupSummary
}

struct DirectorySearchEntry: Decodable, Hashable, Identifiable {
    var entryType: DirectoryEntryType
    var displayName: String
    var simplexName: String? = nil
    let link: String
    var shortDescr: String? = nil
    var image: String? = nil
    var activeAt: Date? = nil
    var createdAt: Date? = nil

    // the link is stable and unique per entry, so it also de-duplicates across pages
    var id: String { link }

    enum CodingKeys: String, CodingKey {
        case entryType, displayName, simplexName, groupLink, shortDescr, image, activeAt, createdAt
    }

    init(from decoder: Decoder) throws {
        let c = try decoder.container(keyedBy: CodingKeys.self)
        entryType = try c.decode(DirectoryEntryType.self, forKey: .entryType)
        displayName = try c.decode(String.self, forKey: .displayName)
        simplexName = try c.decodeIfPresent(String.self, forKey: .simplexName)
        shortDescr = try c.decodeIfPresent(String.self, forKey: .shortDescr)
        image = try c.decodeIfPresent(String.self, forKey: .image)
        activeAt = try c.decodeIfPresent(Date.self, forKey: .activeAt)
        createdAt = try c.decodeIfPresent(Date.self, forKey: .createdAt)
        let groupLink = try c.decode(DirectoryPublicLink.self, forKey: .groupLink)
        // untrusted input: only group and channel links are kept, as the core fetches an invitation link even in a store-only plan
        guard let link = groupLink.connShortLink ?? groupLink.connFullLink,
              let linkType = simplexLinkType(link),
              linkType == .group || linkType == .channel else {
            throw DecodingError.dataCorruptedError(forKey: .groupLink, in: c, debugDescription: "not a group or channel link")
        }
        self.link = link
    }
}

func simplexLinkType(_ s: String) -> SimplexLinkType? {
    if case let .link(text, linkType, _) = strConnectTarget(s), text == s { linkType } else { nil }
}

// entries stay undecoded here so they can be decoded one at a time: one entry the app does not
// understand, because a newer directory added a field, must not discard the whole response
private struct DirectorySearchResponse: Decodable {
    var type: String
    var entries: [JSONValue]?
    var searchCursor: JSONValue?
}

struct DirectorySearchResults {
    var entries: [DirectorySearchEntry]
    // opaque: stored and echoed back on the next request, never inspected
    var cursor: JSONValue?
}

func directorySearchRequestJSON(_ text: String, _ cursor: JSONValue?) -> String {
    var req: [String: JSONValue] = ["type": .string("search"), "searchText": .string(text)]
    if let cursor { req["searchCursor"] = cursor }
    return encodeJSON(JSONValue.object(req))
}

// Anything but a well-formed results response is a failure, not something to salvage: it comes
// from another party, not from our own core.
func parseDirectorySearchResponse(_ resp: JSONValue) -> DirectorySearchResults? {
    guard let r: DirectorySearchResponse = decodeJSONValue(resp), r.type == "searchResults" else {
        return nil
    }
    let entries = (r.entries ?? []).compactMap { (e: JSONValue) -> DirectorySearchEntry? in
        decodeJSONValue(e)
    }
    return DirectorySearchResults(entries: entries, cursor: r.searchCursor)
}

func planLocalChatId(_ plan: ConnectionPlan) -> ChatId? {
    switch plan {
    case let .contactAddress(contactAddressPlan):
        switch contactAddressPlan {
        case let .known(contact), let .connectingProhibit(contact), let .contactViaAddress(contact): return contact.id
        case .ok, .ownLink, .connectingConfirmReconnect: return nil
        }
    case let .groupLink(groupLinkPlan):
        switch groupLinkPlan {
        case let .known(groupInfo), let .ownLink(groupInfo): return groupInfo.id
        case let .connectingProhibit(groupInfo_): return groupInfo_?.id
        case .ok, .connectingConfirmReconnect, .noRelays, .updateRequired: return nil
        }
    case let .invitationLink(invitationLinkPlan):
        switch invitationLinkPlan {
        case let .known(contact): return contact.id
        case let .connecting(contact_): return contact_?.id
        case .ok, .ownLink: return nil
        }
    case .error: return nil
    }
}

struct NameSearchResult: Identifiable {
    let target: String
    let simplexName: String
    let profileName: String?
    let descr: String?
    let image: String?
    let iconName: String
    let localChatId: ChatId?
    // the link the core resolved the name to, never a profile field the name's owner wrote
    let resolvedLink: String?

    var id: String { target }

    init?(target: String, result: ConnectionPlanResult) {
        let profile: (any NamedChat)?
        switch result.connectionPlan {
        case let .contactAddress(contactAddressPlan):
            switch contactAddressPlan {
            case let .ok(contactSLinkData_, _): profile = contactSLinkData_?.profile
            case let .contactViaAddress(contact), let .connectingProhibit(contact), let .known(contact): profile = contact.profile
            case .connectingConfirmReconnect: profile = nil
            case .ownLink: return nil
            }
            iconName = "person.crop.circle.fill"
            resolvedLink = nil
        case let .groupLink(groupLinkPlan):
            let groupProfile: GroupProfile?
            switch groupLinkPlan {
            case let .ok(_, groupSLinkData_, _), let .noRelays(groupSLinkData_), let .updateRequired(groupSLinkData_): groupProfile = groupSLinkData_?.groupProfile
            case let .known(groupInfo), let .ownLink(groupInfo): groupProfile = groupInfo.groupProfile
            case let .connectingProhibit(groupInfo_): groupProfile = groupInfo_?.groupProfile
            case .connectingConfirmReconnect: groupProfile = nil
            }
            profile = groupProfile
            iconName = groupProfile?.isChannel == true ? "antenna.radiowaves.left.and.right.circle.fill" : "person.2.circle.fill"
            resolvedLink = result.connLink.connShortLink
        case .invitationLink, .error:
            return nil
        }
        self.target = target
        simplexName = result.planSimplexName?.shortStr ?? target
        profileName = profile?.displayName
        descr = profile?.shortDescr
        image = profile?.image
        localChatId = planLocalChatId(result.connectionPlan)
    }
}

struct DirectoryResult: Identifiable {
    let entry: DirectorySearchEntry
    let localChatId: ChatId?

    var id: String { entry.id }
}

struct OnlineSearchRows {
    var names: [NameSearchResult]
    var directory: [DirectoryResult]
    var footer: DirectoryFooter?

    var isEmpty: Bool { names.isEmpty && directory.isEmpty && footer == nil }
}