//
//  JellyfinClient+Images.swift
//
//  Copyright 2026 Brendan Szymanski <hello@bscubed.dev>
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <https://www.gnu.org/licenses/>.
//
//  SPDX-License-Identifier: GPL-3.0-or-later
//

import Foundation
import LuminateAPI
import LuminateCore
import OpenAPIRuntime

/// Artwork downloads.
extension JellyfinClient {
    /// Downloads one artwork image, fully buffered.
    ///
    /// The server renders artwork on demand, so ask for the size that will actually be drawn rather
    /// than the original. Passing ``JellyfinImageRequest/tag`` lets caches key the response so a
    /// replaced poster is never served stale.
    ///
    /// The body is collected with a 25 MiB ceiling. No poster, backdrop, or logo comes close; a
    /// larger body raises the OpenAPI runtime's own oversize error rather than a
    /// ``JellyfinClientError``, because that is a server misconfiguration and not a Jellyfin status.
    ///
    /// - Parameters:
    ///   - itemID: The item that owns the artwork. Must not be empty.
    ///   - type: Which artwork slot to fetch.
    ///   - index: Which image within the slot; `nil` means the first.
    ///   - request: The rendition to ask the server for.
    /// - Returns: The encoded image bytes.
    /// - Throws: ``JellyfinClientError/invalidArgument(name:)`` if `itemID` is empty or the current
    ///   specification does not define `type`, or ``JellyfinClientError/notFound`` if the item has
    ///   no image in that slot.
    package func image(
        itemID: String,
        type: JellyfinImageType,
        index: Int32?,
        request: JellyfinImageRequest
    ) async throws -> Data {
        guard !itemID.isEmpty else {
            throw JellyfinClientError.invalidArgument(name: "itemID")
        }
        guard let imageType = Components.Schemas.ImageType(rawValue: type.rawValue) else {
            throw JellyfinClientError.invalidArgument(name: "type")
        }
        guard let index else {
            return try await firstImage(itemID: itemID, imageType: imageType, request: request)
        }
        return try await indexedImage(itemID: itemID, imageType: imageType, index: index, request: request)
    }

    /// Downloads the first image in a slot.
    ///
    /// - Parameters:
    ///   - itemID: The item that owns the artwork.
    ///   - imageType: The generated artwork slot.
    ///   - request: The rendition to ask the server for.
    /// - Returns: The encoded image bytes.
    /// - Throws: ``JellyfinClientError/notFound`` if the item has no image in that slot.
    private func firstImage(
        itemID: String,
        imageType: Components.Schemas.ImageType,
        request: JellyfinImageRequest
    ) async throws -> Data {
        let input = Operations.GetItemImage.Input(
            path: .init(itemId: itemID, imageType: .init(value1: imageType)),
            query: .init(request)
        )
        switch try await current.getItemImage(input) {
        case .ok(let response):
            switch response.body {
            case .image_Ast_(let body):
                return try await Data(collecting: body, upTo: Self.maximumImageBytes)
            }
        case .notFound:
            throw JellyfinClientError.notFound
        case .serviceUnavailable(let response):
            throw JellyfinClientError.serviceUnavailable(
                retryAfterSeconds: response.headers.retryAfter
            )
        case .undocumented(let statusCode, _):
            throw JellyfinClientError.unexpectedStatus(
                operation: Operations.GetItemImage.id,
                statusCode: statusCode
            )
        }
    }

    /// Downloads a specific image within a slot.
    ///
    /// - Parameters:
    ///   - itemID: The item that owns the artwork.
    ///   - imageType: The generated artwork slot.
    ///   - index: Which image within the slot.
    ///   - request: The rendition to ask the server for.
    /// - Returns: The encoded image bytes.
    /// - Throws: ``JellyfinClientError/notFound`` if the item has no image at that index.
    private func indexedImage(
        itemID: String,
        imageType: Components.Schemas.ImageType,
        index: Int32,
        request: JellyfinImageRequest
    ) async throws -> Data {
        let input = Operations.GetItemImageByIndex.Input(
            path: .init(itemId: itemID, imageType: .init(value1: imageType), imageIndex: index),
            query: .init(request)
        )
        switch try await current.getItemImageByIndex(input) {
        case .ok(let response):
            switch response.body {
            case .image_Ast_(let body):
                return try await Data(collecting: body, upTo: Self.maximumImageBytes)
            }
        case .notFound:
            throw JellyfinClientError.notFound
        case .serviceUnavailable(let response):
            throw JellyfinClientError.serviceUnavailable(
                retryAfterSeconds: response.headers.retryAfter
            )
        case .undocumented(let statusCode, _):
            throw JellyfinClientError.unexpectedStatus(
                operation: Operations.GetItemImageByIndex.id,
                statusCode: statusCode
            )
        }
    }

    /// The largest artwork response Luminate will buffer, in bytes.
    private static var maximumImageBytes: Int { 25 * 1024 * 1024 }
}