import Foundation
import XcodeProj
import JSONUtilities

public struct SwiftPackage: Equatable {

    public typealias VersionRequirement = XCRemoteSwiftPackageReference.VersionRequirement

    public let url: String
    public let versionRequirement: VersionRequirement

    public init(url: String, versionRequirement: VersionRequirement) {
        self.url = url
        self.versionRequirement = versionRequirement
    }
}

extension SwiftPackage: JSONObjectConvertible {

    public init(jsonDictionary: JSONDictionary) throws {
        url = try jsonDictionary.json(atKeyPath: "url")
        versionRequirement = try VersionRequirement(jsonDictionary: jsonDictionary)
        try validateVersion()
    }

    private func validateVersion() throws {
        switch versionRequirement {

        case .upToNextMajorVersion(let version):
            try _ = Version(version)

        case .upToNextMinorVersion(let version):
            try _ = Version(version)

        case .range(let from, let to):
            try _ = Version(from)
            try _ = Version(to)

        case .exact(let version):
            try _ = Version(version)

        default:
            break
        }
    }
}

extension SwiftPackage: JSONEncodable {

    public func toJSONValue() -> Any {
        var dictionary: JSONDictionary = [:]
        dictionary["url"] = url

        switch versionRequirement {

        case .upToNextMajorVersion(let version):
            dictionary["majorVersion"] = version
        case .upToNextMinorVersion(let version):
            dictionary["minorVersion"] = version
        case .range(let from, let to):
            dictionary["minVersion"] = from
            dictionary["maxVersion"] = to
        case .exact(let version):
            dictionary["exactVersion"] = version
        case .branch(let branch):
            dictionary["branch"] = branch
        case .revision(let revision):
            dictionary["revision"] = revision
        }
        return dictionary
    }
}

extension SwiftPackage.VersionRequirement: JSONObjectConvertible {

    public init(jsonDictionary: JSONDictionary) throws {
        if jsonDictionary["exactVersion"] != nil {
            self = try .exact(jsonDictionary.json(atKeyPath: "exactVersion"))
        } else if jsonDictionary["version"] != nil {
            self = try .exact(jsonDictionary.json(atKeyPath: "version"))
        } else if jsonDictionary["revision"] != nil {
            self = try .revision(jsonDictionary.json(atKeyPath: "revision"))
        } else if jsonDictionary["branch"] != nil {
            self = try .branch(jsonDictionary.json(atKeyPath: "branch"))
        } else if jsonDictionary["minVersion"] != nil && jsonDictionary["maxVersion"] != nil {
            let minimum: String = try jsonDictionary.json(atKeyPath: "minVersion")
            let maximum: String = try jsonDictionary.json(atKeyPath: "maxVersion")
            self = .range(from: minimum, to: maximum)
        } else if jsonDictionary["minorVersion"] != nil {
            self = try .upToNextMinorVersion(jsonDictionary.json(atKeyPath: "minorVersion"))
        } else if jsonDictionary["majorVersion"] != nil {
            self = try .upToNextMajorVersion(jsonDictionary.json(atKeyPath: "majorVersion"))
        } else if jsonDictionary["from"] != nil {
            self = try .upToNextMajorVersion(jsonDictionary.json(atKeyPath: "from"))
        } else {
            throw SpecParsingError.unknownPackageRequirement(jsonDictionary)
        }
    }
}