import Foundation

enum ImageSourceResolver {
    static func resolve(_ raw: String?) -> String? {
        guard var normalized = raw?.trimmingCharacters(in: .whitespacesAndNewlines),
              normalized.isEmpty == false else { return nil }

        normalized = normalized.replacingOccurrences(of: "\\/", with: "/")
        let lower = normalized.lowercased()

        if lower.hasPrefix("http://") || lower.hasPrefix("https://") || lower.hasPrefix("data:image") {
            return normalized
        }

//        if let base64DataURL = normalizedBase64DataURL(normalized) {
//            return base64DataURL
//        }

        let base = ApiConfig.baseURL.absoluteString.trimmingCharacters(in: CharacterSet(charactersIn: "/"))
        let path = normalized.hasPrefix("/") ? normalized : "/\(normalized)"
        return "\(base)\(path)"
    }

    private static func normalizedBase64DataURL(_ raw: String) -> String? {
        let trimmed = raw.trimmingCharacters(in: .whitespacesAndNewlines)
        guard trimmed.isEmpty == false else { return nil }

        let payload: String
        if let marker = trimmed.range(of: "base64,", options: [.caseInsensitive]) {
            payload = String(trimmed[marker.upperBound...])
        } else {
            payload = trimmed
        }

        let sanitized = payload
            .replacingOccurrences(of: "\n", with: "")
            .replacingOccurrences(of: "\r", with: "")
            .replacingOccurrences(of: " ", with: "")

        guard sanitized.count >= 64 else { return nil }
        guard Data(base64Encoded: sanitized, options: [.ignoreUnknownCharacters]) != nil else { return nil }
        return "data:image/png;base64,\(sanitized)"
    }
}