import Foundation
#if canImport(FoundationNetworking)
import FoundationNetworking
#endif
import XMLCoder
import DiscordBM

struct Wolfram {
    static let token = ProcessInfo.processInfo.environment["WOLFRAM_APP_ID"]!
    static let apiUrl = "http://api.wolframalpha.com/v2/query"

    static func getWolfram(_ question: String) async throws -> (String, URL?) {
        let encQuestion = question.addingPercentEncoding(withAllowedCharacters: .alphanumerics)
        let url = URL(string: "\(apiUrl)?appid=\(token)&input=\(encQuestion!)")!
        let (data, _) = try await URLSession.shared.data(from: url)

        let wolframRes = try XMLDecoder().decode(WolframQueryResult.self, from: data)

        let resultPod = wolframRes.pod.first(where: { $0.primary ?? false || $0.id == "Result" })

        var ans: String?
        var img: URL?

        if let resultPod = resultPod {
            ans = String(resultPod.subpod.compactMap(\.plaintext).joined(by: "\n"))
                .replacingOccurrences(of: " | ", with: ": ")
        }
        if let imgPod = wolframRes.pod.first(where: {
            ["RootPlot", "NumberLine", "Plot", "ImplicitPlot", "3DPlot"].contains($0.id) ||
            ($0.id == "Example" && $0.scanner == "Dice")
        }) {
            ans = ans ?? "Plot:"
            img = imgPod.subpod.first?.img.src
        }

        if ans == nil,
        let maybePod = wolframRes.pod.first(where: { $0.title == "Input interpretation" }),
        let maybeText = maybePod.subpod.first?.plaintext
            .replacingOccurrences(of: " | ", with: ": ") {
            ans = "<:smol_rise:852763040452575252> I don't know. Maybe you meant '\(maybeText)'"
        }

        return (ans ?? "<:smol_rise:852763040452575252> sorry, I have no idea (´._.`)", img)
    }

    static func handleMath(
        _ args: ArraySlice<String.SubSequence>,
        client: DiscordClient,
        ctx: Gateway.MessageCreate
    ) async throws {
        try await client.triggerTypingIndicator(channelId: ctx.channel_id).guardSuccess()

        let question = String(args.joined(by: " "))

        let (answer, img) = try await getWolfram(question)

        var attachments: [Payloads.Attachment] = []
        var files: [RawFile] = []

        if let img = img {
            let data = try? await URLSession.shared.data(from: img)
            if let data = data?.0 {
                attachments.append(.init(index: 0, filename: "img.gif"))
                files.append(.init(data: .init(data: data), filename: "img.gif"))
            }
        }

        try await client.createMessage(channelId: ctx.channel_id, payload: .init(
            content: answer,
            message_reference: .init(
                type: .default,
                message_id: ctx.id,
                channel_id: ctx.channel_id,
                guild_id: ctx.guild_id,
            ),
            files: files,
            attachments: attachments
        )).guardSuccess()
    }
}

struct WolframQueryResult: Codable {
    struct Pod: Codable {
        let title: String
        let id: String
        let scanner: String
        let primary: Bool?

        let subpod: [Subpod]
    }

    struct Subpod: Codable {
        let title: String
        let img: Image
        let plaintext: String
    }

    struct Image: Codable {
        let src: URL
    }

    let success: Bool
    let numpods: Int

    let pod: [Pod]
}