import Foundation

struct ContactMetadata {
    var isFavorite: Bool = false
    var isMyCard: Bool = false

    var hasAnyValue: Bool {
        isFavorite || isMyCard
    }
}

enum ContactMetadataDSL {
    private static let startMarker = "[[kontakte]]"
    private static let endMarker = "[[/kontakte]]"

    static func parse(note: String) -> ContactMetadata {
        guard let range = metadataBlockRange(in: note) else {
            return ContactMetadata()
        }

        let block = note[range]
        var metadata = ContactMetadata()

        for rawLine in block.components(separatedBy: .newlines) {
            let line = rawLine.trimmingCharacters(in: .whitespacesAndNewlines)
            if line == "favorite=1" {
                metadata.isFavorite = true
            } else if line == "my_card=1" {
                metadata.isMyCard = true
            }
        }

        return metadata
    }

    static func updating(note: String, metadata: ContactMetadata) -> String {
        var base = note
        if let range = metadataBlockRange(in: note) {
            base.removeSubrange(range)
        }
        base = base.trimmingCharacters(in: .whitespacesAndNewlines)

        guard metadata.hasAnyValue else {
            return base
        }

        var lines: [String] = []
        lines.append(startMarker)
        if metadata.isFavorite {
            lines.append("favorite=1")
        }
        if metadata.isMyCard {
            lines.append("my_card=1")
        }
        lines.append(endMarker)
        let block = lines.joined(separator: "\n")

        if base.isEmpty {
            return block
        }
        return base + "\n\n" + block
    }

    private static func metadataBlockRange(in note: String) -> Range<String.Index>? {
        guard let start = note.range(of: startMarker),
              let end = note.range(of: endMarker, range: start.upperBound..<note.endIndex) else {
            return nil
        }
        return start.lowerBound..<end.upperBound
    }
}