import Foundation

enum GenerationError: Error {
    case missingMarkerInTemplate(String)
    case failedToLoadTemplate(String)
    case failedToWriteFile(String)
    case failedToOpenFile(String)
    case failedToDecodeJSON(file: String, error: String)
    case invalidLanguageSpecification(String)
    case invalidDateInPageMetadata(String)
    case failedToEncodeJSON(String)
    case missingSectionMetadata(section: String, language: String)
    case missingPageMetadata(page: String, language: String)
    case missingPage(page: String, language: String)
    case missingImage(String)
    case conflictingImageSources(output: String, in1: String, in2: String)
    case conflictingImageRatios(output: String, in1: String, in2: String)
    case failedToGenerateImage(String)
    case imageRatioMismatch(String)

}

func wrap<T>(_ error: GenerationError, execute: () throws -> T) rethrows -> T {
    do {
        return try execute()
    } catch let underlyingError {
        print(underlyingError)
        throw error
    }
}

func wrap<T>(_ error: (Error) -> GenerationError, execute: () throws -> T) rethrows -> T {
    do {
        return try execute()
    } catch let underlyingError {
        print(underlyingError)
        throw error(underlyingError)
    }
}

extension Optional {

    func unwrap(or error: GenerationError) throws -> Wrapped {
        switch self {
        case .none:
            throw error
        case .some(let wrapped):
            return wrapped
        }
    }
}