//===----------------------------------------------------------------------===//
// Copyright © 2025 Apple Inc. and the container project authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//===----------------------------------------------------------------------===//

import ContainerNetworkService
import ContainerizationOCI

public struct ContainerConfiguration: Sendable, Codable {
    /// Identifier for the container.
    public var id: String
    /// Image used to create the container.
    public var image: ImageDescription
    /// External mounts to add to the container.
    public var mounts: [Filesystem] = []
    /// Ports to publish from container to host.
    public var publishedPorts: [PublishPort] = []
    /// Sockets to publish from container to host.
    public var publishedSockets: [PublishSocket] = []
    /// Key/Value labels for the container.
    public var labels: [String: String] = [:]
    /// System controls for the container.
    public var sysctls: [String: String] = [:]
    /// The networks the container will be added to.
    public var networks: [AttachmentConfiguration] = []
    /// The DNS configuration for the container.
    public var dns: DNSConfiguration? = nil
    /// Whether to enable rosetta x86-64 translation for the container.
    public var rosetta: Bool = false
    /// Initial or main process of the container.
    public var initProcess: ProcessConfiguration
    /// Platform for the container.
    public var platform: ContainerizationOCI.Platform = .current
    /// Resource values for the container.
    public var resources: Resources = .init()
    /// Name of the runtime that supports the container.
    public var runtimeHandler: String = "container-runtime-linux"
    /// Configure exposing virtualization support in the container.
    public var virtualization: Bool = false
    /// Enable SSH agent socket forwarding from host to container.
    public var ssh: Bool = false

    enum CodingKeys: String, CodingKey {
        case id
        case image
        case mounts
        case publishedPorts
        case publishedSockets
        case labels
        case sysctls
        case networks
        case dns
        case rosetta
        case initProcess
        case platform
        case resources
        case runtimeHandler
        case virtualization
        case ssh
    }

    /// Create a configuration from the supplied Decoder, initializing missing
    /// values where possible to reasonable defaults.
    public init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)

        id = try container.decode(String.self, forKey: .id)
        image = try container.decode(ImageDescription.self, forKey: .image)
        mounts = try container.decodeIfPresent([Filesystem].self, forKey: .mounts) ?? []
        publishedPorts = try container.decodeIfPresent([PublishPort].self, forKey: .publishedPorts) ?? []
        publishedSockets = try container.decodeIfPresent([PublishSocket].self, forKey: .publishedSockets) ?? []
        labels = try container.decodeIfPresent([String: String].self, forKey: .labels) ?? [:]
        sysctls = try container.decodeIfPresent([String: String].self, forKey: .sysctls) ?? [:]

        // NOTE: migrates [String] to [AttachmentConfiguration]; remove [String] support in a later release
        if container.contains(.networks) {
            do {
                networks = try container.decode([AttachmentConfiguration].self, forKey: .networks)
            } catch {
                let networkIds = try container.decode([String].self, forKey: .networks)
                networks = try Utility.getAttachmentConfigurations(containerId: id, networkIds: networkIds)
            }
        } else {
            networks = []
        }

        dns = try container.decodeIfPresent(DNSConfiguration.self, forKey: .dns)
        rosetta = try container.decodeIfPresent(Bool.self, forKey: .rosetta) ?? false
        initProcess = try container.decode(ProcessConfiguration.self, forKey: .initProcess)
        platform = try container.decodeIfPresent(ContainerizationOCI.Platform.self, forKey: .platform) ?? .current
        resources = try container.decodeIfPresent(Resources.self, forKey: .resources) ?? .init()
        runtimeHandler = try container.decodeIfPresent(String.self, forKey: .runtimeHandler) ?? "container-runtime-linux"
        virtualization = try container.decodeIfPresent(Bool.self, forKey: .virtualization) ?? false
        ssh = try container.decodeIfPresent(Bool.self, forKey: .ssh) ?? false
    }

    public struct DNSConfiguration: Sendable, Codable {
        public static let defaultNameservers = ["1.1.1.1"]

        public let nameservers: [String]
        public let domain: String?
        public let searchDomains: [String]
        public let options: [String]

        public init(
            nameservers: [String] = defaultNameservers,
            domain: String? = nil,
            searchDomains: [String] = [],
            options: [String] = []
        ) {
            self.nameservers = nameservers
            self.domain = domain
            self.searchDomains = searchDomains
            self.options = options
        }
    }

    /// Resources like cpu, memory, and storage quota.
    public struct Resources: Sendable, Codable {
        /// Number of CPU cores allocated.
        public var cpus: Int = 4
        /// Memory in bytes allocated.
        public var memoryInBytes: UInt64 = 1024.mib()
        /// Storage quota/size in bytes.
        public var storage: UInt64?

        public init() {}
    }

    public init(
        id: String,
        image: ImageDescription,
        process: ProcessConfiguration
    ) {
        self.id = id
        self.image = image
        self.initProcess = process
    }
}