import Foundation

public struct Emoji: Sendable {
    public let value: String
    public let name: String
    public let category: String
}

public enum EmojiCatalog {
    private struct Entry: Sendable {
        let emoji: Emoji
        let searchText: String
    }

    private static let entries: [Entry] = {
        // SwiftPM's generated accessor does not search Contents/Resources in a packaged app.
        let packagedBundle = Bundle.main.resourceURL.flatMap {
            Bundle(url: $0.appendingPathComponent("Conjure_ConjureKit.bundle", isDirectory: true))
        }
        let bundle = packagedBundle ?? Bundle.module
        guard let url = bundle.url(forResource: "emoji", withExtension: "tsv"),
              let contents = try? String(contentsOf: url, encoding: .utf8) else {
            preconditionFailure("The bundled emoji catalog is missing or unreadable")
        }

        // Pinned github/gemoji v4.1.0; attribution and license accompany the TSV.
        return contents.split(whereSeparator: \.isNewline).map { line in
            let fields = line.split(separator: "\t", omittingEmptySubsequences: false)
            precondition(fields.count == 5, "Invalid bundled emoji catalog row")
            return Entry(
                emoji: Emoji(value: String(fields[0]), name: String(fields[1]), category: String(fields[2])),
                searchText: normalized([fields[0], fields[1], fields[3], fields[4]].joined(separator: " "))
            )
        }
    }()

    public static let all: [Emoji] = entries.map(\.emoji)

    public static let categories: [String] = {
        var seen = Set<String>()
        return all.compactMap { seen.insert($0.category).inserted ? $0.category : nil }
    }()

    /// Matches every query word against names, GitHub aliases, tags, or literal emoji.
    /// Category names use the exact values supplied by `categories`; results retain catalog order.
    public static func search(_ query: String, category: String? = nil) -> [Emoji] {
        let words = normalized(query).split(whereSeparator: \.isWhitespace)
        if words.isEmpty && category == nil { return all }
        return entries.compactMap { entry in
            guard category == nil || entry.emoji.category == category,
                  words.allSatisfy({ entry.searchText.contains($0) }) else { return nil }
            return entry.emoji
        }
    }

    private static func normalized(_ text: String) -> String {
        text.folding(options: [.caseInsensitive, .diacriticInsensitive], locale: Locale(identifier: "en_US_POSIX"))
            .replacingOccurrences(of: "_", with: " ")
            .replacingOccurrences(of: ":", with: " ")
    }
}