//===----------------------------------------------------------------------===//
// Copyright © 2025 Apple Inc. and the container project authors. All rights reserved.
//
// 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

    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
    }

    /// 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
    }

    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
    }
}