// ===----------------------------------------------------------------------===
// 
// This source file is part of the Amiibo Service open source project
// 
// Copyright (c) 2026 Röck+Cöde VoF. and the Amiibo Service project authors
// Licensed under Apache license v2.0
// 
// See LICENSE for license information
// See CONTRIBUTORS for the list of Amiibo Service project authors
//
// SPDX-License-Identifier: Apache-2.0
// 
// ===----------------------------------------------------------------------===

import Foundation
import OpenAPIRuntime
import OpenAPIURLSession

/// A type that implements a live client to the [Amiibo API](https://www.amiiboapi.org) online service.
public struct AmiiboLiveClient: Sendable {
    
    // MARK: Constants
    
    /// The base URL of the live service, resolved once from the server defined in the OpenAPI specification.
    ///
    /// The validity of the URL is guaranteed by the bundled `openapi.yaml` specification and enforced by a unit test, so resolution is not expected to fail at runtime.
    static let serverURL: URL = {
        guard let url = try? Servers.Server1.url() else {
            fatalError("The server URL defined in the OpenAPI specification could not be resolved. Verify that the 'openapi.yaml' server definition is valid.")
        }
        
        return url
    }()
    
    // MARK: Properties
    
    /// A client generated by the OpenAPI Runtime library to perform API calls.
    private let client: Client
    
    // MARK: Initializers
    
    /// Initializes this client with a transport for performing HTTP operations.
    /// - Parameter transport: A transport that performs HTTP operations. Defaults to a `URLSessionTransport` using the shared session.
    public init(transport: any ClientTransport = URLSessionTransport()) {
        self.client = .init(
            serverURL: Self.serverURL,
            configuration: .init(dateTranscoder: ISODateTimeTranscoder()),
            transport: transport
        )
    }
    
}

// MARK: - AmiiboClient
// TODO: Remove the documentation from the functions inside the following extension as the `--enable-inherited-docs` flag when generating DocC documentation is not working as intended (?).

extension AmiiboLiveClient: AmiiboClient {

    // MARK: Functions
    
    /// Gets a list of amiibo items based on a given filter.
    /// - Parameter filter: A filter to remove unwanted items from the result.
    /// - Returns: A list of filtered amiibo items.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    public func getAmiibos(
        by filter: AmiiboFilter
    ) async throws(AmiiboServiceError) -> [Amiibo] {
        try await fetchAmiibos(filter)
    }

    /// Gets a list of amiibo series based on a given filter.
    /// - Parameter filter: A filter to remove unwanted items from the result.
    /// - Returns: A list of filtered amiibo series.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    public func getAmiiboSeries(
        by filter: AmiiboSeriesFilter
    ) async throws(AmiiboServiceError) -> [AmiiboSeries] {
        try await fetchAmiiboSeries(filter)
    }
 
    /// Gets a list of amiibo types based on a given filter.
    /// - Parameter filter: A filter to remove unwanted items from the result.
    /// - Returns: A list of filtered amiibo types.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    public func getAmiiboTypes(
        by filter: AmiiboTypeFilter
    ) async throws(AmiiboServiceError) -> [AmiiboType] {
        try await fetchAmiiboTypes(filter)
    }

    /// Gets a list of game characters based on a given filter.
    /// - Parameter filter: A filter to remove unwanted items from the result.
    /// - Returns: A list of filtered game characters.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    public func getGameCharacters(
        by filter: GameCharacterFilter
    ) async throws(AmiiboServiceError) -> [GameCharacter] {
        try await fetchGameCharacters(filter)
    }

    /// Gets a list of game series based on a given filter.
    /// - Parameter filter: A filter to remove unwanted items from the result.
    /// - Returns: A list of filtered game series.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    public func getGameSeries(
        by filter: GameSeriesFilter
    ) async throws(AmiiboServiceError) -> [GameSeries] {
        try await fetchGameSeries(filter)
    }

    /// Gets the date when the data was last updated.
    /// - Returns: A last updated date.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    public func getLastUpdated() async throws(AmiiboServiceError) -> Date {
        try await fetchLastUpdated()
    }
    
}

// MARK: - Helpers

private extension AmiiboLiveClient {
    
    // MARK: Functions
    
    /// Fetches a list of amiibo items based on a given filter.
    /// - Parameter filter: A filter to remove unwanted items from the result.
    /// - Returns: A list of fetched amiibo items filtered, if requested.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    func fetchAmiibos(
        _ filter: AmiiboFilter
    ) async throws(AmiiboServiceError) -> [Amiibo] {
        let response = try await perform {
            try await client.getAmiibos(.init(query: .init(
                id: filter.identifier,
                head: filter.head,
                tail: filter.tail,
                name: filter.name,
                _type: filter.type,
                amiiboSeries: filter.series,
                character: filter.gameCharacter,
                gameseries: filter.gameSeries,
                showgames: filter.showGames,
                showusage: filter.showUsage
            )))
        }
        
        switch response {
        case let .ok(ok):
            switch ok.body {
            case let .json(output):
                switch output.amiibo {
                case let .Amiibo(object):
                    return [Amiibo(object)]
                case let .AmiiboList(list):
                    return list
                        .map { Amiibo($0) }
                        .sorted { $0.identifier < $1.identifier }
                case .none:
                    return []
                }
            }
        case .badRequest:
            throw AmiiboServiceError.badRequest
        case .notFound:
            throw AmiiboServiceError.notFound
        case .internalServerError:
            throw AmiiboServiceError.notAvailable
        case let .undocumented(statusCode, _):
            throw AmiiboServiceError.undocumented(statusCode)
        }
    }

    /// Fetches a list of amiibo series based on a given filter.
    /// - Parameter filter: A filter to remove unwanted items from the result.
    /// - Returns: A list of fetched amiibo series filtered, if requested.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    func fetchAmiiboSeries(
        _ filter: AmiiboSeriesFilter
    ) async throws(AmiiboServiceError) -> [AmiiboSeries] {
        let response = try await perform {
            try await client.getAmiiboSeries(.init(query: .init(
                key: filter.key,
                name: filter.name
            )))
        }
        
        switch response {
        case let .ok(ok):
            switch ok.body {
            case let .json(output):
                switch output.amiibo {
                case let .AmiiboSeries(payload):
                    return makeModels(from: [payload])
                case let .AmiiboSeriesList(list):
                    return makeModels(from: list)
                }
            }
        case .badRequest:
            throw AmiiboServiceError.badRequest
        case .internalServerError:
            throw AmiiboServiceError.notAvailable
        case .notFound:
            throw AmiiboServiceError.notFound
        case let .undocumented(statusCode, _):
            throw AmiiboServiceError.undocumented(statusCode)
        }
    }
    
    /// Fetches a list of amiibo types based on a given filter.
    /// - Parameter filter: A filter to remove unwanted items from the result.
    /// - Returns: A list of fetched amiibo types filtered, if requested.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    func fetchAmiiboTypes(
        _ filter: AmiiboTypeFilter
    ) async throws(AmiiboServiceError) -> [AmiiboType] {
        let response = try await perform {
            try await client.getAmiiboTypes(.init(query: .init(
                key: filter.key,
                name: filter.name
            )))
        }
        
        switch response {
        case let .ok(ok):
            switch ok.body {
            case let .json(output):
                switch output.amiibo {
                case let .AmiiboType(payload):
                    return makeModels(from: [payload])
                case let .AmiiboTypeList(list):
                    return makeModels(from: list)
                }
            }
        case .badRequest:
            throw AmiiboServiceError.badRequest
        case .internalServerError:
            throw AmiiboServiceError.notAvailable
        case .notFound:
            throw AmiiboServiceError.notFound
        case let .undocumented(statusCode, _):
            throw AmiiboServiceError.undocumented(statusCode)
        }
    }
    
    /// Fetches a list of game characters based on a given filter.
    /// - Parameter filter: A filter to remove unwanted items from the result.
    /// - Returns: A list of fetched game characters filtered, if requested.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    func fetchGameCharacters(
        _ filter: GameCharacterFilter
    ) async throws(AmiiboServiceError) -> [GameCharacter] {
        let response = try await perform {
            try await client.getGameCharacters(.init(query: .init(
                key: filter.key,
                name: filter.name
            )))
        }
        
        switch response {
        case let .ok(ok):
            switch ok.body {
            case let .json(output):
                switch output.amiibo {
                case let .GameCharacter(payload):
                    return makeModels(from: [payload])
                case let .GameCharacterList(list):
                    return makeModels(from: list)
                }
            }
        case .badRequest:
            throw AmiiboServiceError.badRequest
        case .internalServerError:
            throw AmiiboServiceError.notAvailable
        case .notFound:
            throw AmiiboServiceError.notFound
        case let .undocumented(statusCode, _):
            throw AmiiboServiceError.undocumented(statusCode)
        }
    }
    
    /// Fetches a list of game series based on a given filter.
    /// - Parameter filter: A filter to remove unwanted items from the result.
    /// - Returns: A list of fetched game series filtered, if requested.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    func fetchGameSeries(
        _ filter: GameSeriesFilter
    ) async throws(AmiiboServiceError) -> [GameSeries] {
        let response = try await perform {
            try await client.getGameSeries(.init(query: .init(
                key: filter.key,
                name: filter.name
            )))
        }
        
        switch response {
        case let .ok(ok):
            switch ok.body {
            case let .json(output):
                switch output.amiibo {
                case let .GameSeries(payload):
                    return makeModels(from: [payload])
                case let .GameSeriesList(list):
                    return makeModels(from: list)
                }
            }
        case .badRequest:
            throw AmiiboServiceError.badRequest
        case .internalServerError:
            throw AmiiboServiceError.notAvailable
        case .notFound:
            throw AmiiboServiceError.notFound
        case let .undocumented(statusCode, _):
            throw AmiiboServiceError.undocumented(statusCode)
        }
    }
    
    /// Fetches the date when the data was last updated.
    /// - Returns: A fetched last updated date.
    /// - Throws: An ``AmiiboServiceError`` error in case some issue is encountered while generating the result.
    func fetchLastUpdated() async throws(AmiiboServiceError) -> Date {
        let response = try await perform {
            try await client.getLastUpdated()
        }
        
        switch response {
        case let .ok(ok):
            switch ok.body {
            case let .json(output):
                return output.lastUpdated
            }
        case .internalServerError:
            throw AmiiboServiceError.notAvailable
        case let .undocumented(statusCode, _):
            throw AmiiboServiceError.undocumented(statusCode)
        }
    }
    
    /// Performs an API call, mapping any error thrown by the underlying client to an ``AmiiboServiceError`` error.
    /// - Parameter operation: A closure that performs the API call.
    /// - Returns: The output of the performed API call.
    /// - Throws: An ``AmiiboServiceError`` error in case the API call failed.
    func perform<Output>(
        _ operation: () async throws -> Output
    ) async throws(AmiiboServiceError) -> Output {
        do {
            return try await operation()
        } catch {
            try handle(error: error)
        }
    }
    
    /// Maps a list of key-name payloads into a sorted list of models.
    /// - Parameter payloads: A list of payloads to map into models.
    /// - Returns: A list of models sorted by their keys in ascending order.
    func makeModels<Model: KeyNameModel>(from payloads: [some KeyNamePayload]) -> [Model] {
        payloads
            .map { Model($0) }
            .sorted { $0.key < $1.key }
    }
    
    /// Maps a given error to an ``AmiiboServiceError`` error.
    /// - Parameter error: An error to map.
    /// - Throws: An ``AmiiboServiceError`` error that corresponds to the given error.
    func handle(error: any Error) throws(AmiiboServiceError) -> Never {
        switch error {
        case is CancellationError:
            throw AmiiboServiceError.cancelled
        case let clientError as ClientError:
            switch clientError.underlyingError {
            case is DecodingError:
                throw AmiiboServiceError.decoding
            case let urlError as URLError:
                switch urlError.code {
                case .cancelled:
                    throw AmiiboServiceError.cancelled
                case .cannotParseResponse:
                    throw AmiiboServiceError.decoding
                case .cannotFindHost,
                     .cannotConnectToHost,
                     .dataNotAllowed,
                     .dnsLookupFailed,
                     .internationalRoamingOff,
                     .networkConnectionLost,
                     .notConnectedToInternet,
                     .secureConnectionFailed,
                     .timedOut:
                    throw AmiiboServiceError.notAvailable
                default:
                    throw AmiiboServiceError.unknown(String(describing: urlError))
                }
            default:
                throw AmiiboServiceError.unknown(String(describing: clientError.underlyingError))
            }
        default:
            throw AmiiboServiceError.unknown(String(describing: error))
        }
    }
    
}