module PublishHelperBot.YoutubeDl

open System
open System.Collections.Generic
open System.IO
open System.Net.Http
open System.Text
open System.Text.Json
open System.Threading.Tasks
open Microsoft.FSharp.Core
open PublishHelperBot.Environment
open PublishHelperBot.Types

type YoutubeDlClientConfig = {
    BaseUrl: string
    Client: HttpClient
}

[<RequireQualifiedAccess>]
module YoutubeDlClient =
    type private YoutubeDlClientActions = Create | Check | Delete

    type private HttpMethods = GET | POST | DELETE

    type private Msg =
        | CreateJob of CreateYoutubeDlJob * tcs: TaskCompletionSource<CreateJobResult>
        | CheckJob of externalId: Guid * tcs: TaskCompletionSource<CheckJobResult>
        | CleanJob of externalId: Guid * tcs: TaskCompletionSource<CleanJobResult>

    let private getApiPrefix baseUrl = $"{baseUrl}api/"

    let private resolvePath baseUrl (action: YoutubeDlClientActions) =
        let apiPrefix = getApiPrefix baseUrl
        match action with
        | Create -> $"{apiPrefix}download"
        | Check -> $"{apiPrefix}status"
        | Delete -> $"{apiPrefix}clear"

    let private doHttp
        (method: HttpMethods)
        (content: HttpContent)
        (client: HttpClient)
        (url: string): Async<Result<'TRes, YoutubeDlError>> =
        task {
            try
                let! contentText = content.ReadAsStringAsync()
                Logging.logger.Information("Sending request to youtube api, url = {Url}, content = {Content}", url, contentText)
                let! res =
                    match method with
                    | POST -> client.PostAsync(url, content)
                    | GET -> client.GetAsync(url)
                    | DELETE -> client.DeleteAsync(url)

                let! content = res.Content.ReadAsStringAsync()
                Logging.logger.Information("Response from youtube api, response = {Response}", content)
                return
                    match res.IsSuccessStatusCode with
                    | true ->
                        Logging.logger.Information("Response OK")
                        Ok (JsonSerializer.Deserialize<'TRes>(content))
                    | false ->
                        Logging.logger.Error("Response network error")
                        Error { Message = "Unknown network error" }
            with ex ->
                Logging.logger.Error(ex, "Youtube api error")
                return Error { Message = ex.Message  }
        } |> Async.AwaitTask

    let private createInbox(config: YoutubeDlClientConfig) = MailboxProcessor.Start(fun inbox ->
        let rec loop() =
            async {
                match! inbox.Receive() with
                | CreateJob(args, tcs) ->
                    Logging.logger.Information("Received youtube api create job")
                    async {
                        try
                            let json = args |> JsonSerializer.Serialize
                            Logging.logger.Information("Sending create job = {Job}", json)
                            use content = new StringContent(json, Encoding.UTF8, "application/json")
                            let! result =
                                (config.Client, resolvePath config.BaseUrl Create)
                                ||> doHttp POST content
                            Logging.logger.Information("Received response from youtube api for create job")
                            tcs.SetResult(result)

                        with ex ->
                            Logging.logger.Error(ex, "Failed to create youtube api job")
                            tcs.SetResult(Error {
                                Message = ex.Message
                            })

                    } |> Async.Start

                    return! loop ()

                | CheckJob (externalId, tcs) ->
                    Logging.logger.Information("Received youtube api check job, externalId = {id}", externalId)
                    async {
                        try
                            let arg = [KeyValuePair("id", externalId.ToString())]
                            use content = new FormUrlEncodedContent(arg)
                            Logging.logger.Information("Sending youtube api check job")
                            let! query = content.ReadAsStringAsync() |> Async.AwaitTask
                            let! result =
                                (config.Client, $"{resolvePath config.BaseUrl Check}?{query}")
                                ||> doHttp GET content
                            Logging.logger.Information("Received response from youtube api for check job")
                            tcs.SetResult(result)

                        with ex ->
                            Logging.logger.Error(ex, "Failed to check youtube api job")
                            tcs.SetResult(Error {
                                Message = ex.Message
                            })
                    } |> Async.Start

                    return! loop ()

                | CleanJob(externalId, tcs) ->
                    Logging.logger.Information("Received youtube api clean job, externalId = {id}", externalId)
                    async {
                        try
                            let arg = [KeyValuePair("id", externalId.ToString())]
                            use content = new FormUrlEncodedContent(arg)
                            Logging.logger.Information("Sending youtube api clean job")
                            let! query = content.ReadAsStringAsync() |> Async.AwaitTask
                            let! result =
                                (config.Client, $"{resolvePath config.BaseUrl Delete}?{query}")
                                ||> doHttp DELETE content
                            Logging.logger.Information("Received response from youtube api for clean job")
                            tcs.SetResult(result)

                        with ex ->
                            Logging.logger.Error(ex, "Failed to clean youtube api job")
                            tcs.SetResult(Error {
                                Message = ex.Message
                            })
                    } |> Async.Start

                    return! loop ()
            }
        loop ()
    )

    let createClient (config: YoutubeDlClientConfig) =
        let inbox = createInbox(config)
        { new IYoutubeDlClient with
            member this.CreateJob(args) =
                let tcs = TaskCompletionSource<_>()
                inbox.Post(CreateJob(args, tcs))
                tcs.Task |> Async.AwaitTask

            member this.CheckJob externalId =
                let tcs = TaskCompletionSource<_>()
                inbox.Post(CheckJob(externalId, tcs))
                tcs.Task |> Async.AwaitTask

            member this.CleanJob externalId =
                let tcs = TaskCompletionSource<_>()
                inbox.Post(CleanJob(externalId, tcs))
                tcs.Task |> Async.AwaitTask }

[<RequireQualifiedAccess>]
module YoutubeDlService =
    type private Msg =
        | AddJob of url: string * TaskCompletionSource<Guid>
        | CheckJob

    type private JobState =
        | Created
        | Awaiting of Guid

    type private YoutubeDlJob = {
        InternalId: Guid
        State: JobState
        Url: string
        SavePath: string
    }

    let private createJob (client: IYoutubeDlClient) (job: YoutubeDlJob) =
        async {
            Logging.logger.Information("Sending create job to youtube client, job = {job}", job.InternalId)
            let! result =
                client.CreateJob {
                    Url = job.Url
                    SavePath = job.SavePath
                }
            match result with
            | Ok task ->
                Logging.logger.Information(
                    "Created job on youtube client = {job}, externalId = {externalId}",
                    job.InternalId,
                    task.Task)
                let updated = {
                    job with
                        State = JobState.Awaiting task.Task
                }
                return Some updated

            | Error e ->
                Logging.logger.Error(
                    "Failed to create job on client = {job}, message = {message}",
                    job.InternalId,
                    e.Message)
                return None
        }

    let private getCurrentJob
        (jobQueue: Queue<YoutubeDlJob>)
        (current: YoutubeDlJob option) =
        match current with
        | Some current ->
            Some current

        | None ->
            match jobQueue.TryDequeue() with
            | true, job ->
                Some job
            | _ ->
                None

    let private createServiceInbox
        (youtubeDlClient: IYoutubeDlClient)
        (tgService: ITgService) =

        MailboxProcessor.Start(fun inbox ->
            let postCheck() =
                async {
                    do! Async.Sleep(TimeSpan.FromSeconds 5)
                    inbox.Post(CheckJob)
                } |> Async.Start

            let rec loop
                (jobQueue: Queue<YoutubeDlJob>)
                (current: YoutubeDlJob option) =
                async {
                    match! inbox.Receive() with
                    | AddJob (url, tcs) ->
                        Logging.logger.Information("Adding new url = {url}", url)
                        let id = Guid.NewGuid()
                        let job = {
                            InternalId = id
                            State = Created
                            Url = url
                            SavePath = $"{Path.GetTempFileName()}.mp4"
                        }
                        tcs.SetResult(id)
                        jobQueue.Enqueue(job)

                        if current.IsNone then
                            inbox.Post(CheckJob)

                        Logging.logger.Information(
                            "Added new job = {job}, url = {url}, path = {path}",
                            job.InternalId,
                            url,
                            job.SavePath)
                        return! loop jobQueue current

                    | CheckJob ->
                        let currentJob = getCurrentJob jobQueue current
                        match currentJob with
                        | Some job ->
                            Logging.logger.Information("Checking job = {job}, state = {state}", job.InternalId, job.State)
                            match job.State with
                            | Created ->
                                match! createJob youtubeDlClient job with
                                | Some job ->
                                    postCheck()
                                    return! loop jobQueue (Some job)

                                | None ->
                                    postCheck()
                                    return! loop jobQueue None

                            | Awaiting externalId ->
                                Logging.logger.Information("Checking job = {job}", externalId)
                                let! checkResult = youtubeDlClient.CheckJob(externalId)
                                match checkResult with
                                | Ok x when x.State.Equals("Finished", StringComparison.OrdinalIgnoreCase) ->
                                    Logging.logger.Information("Sending post video from job = {job}", externalId)
                                    let infoDict =
                                        x.VideoInfo |> Option.bind (fun v -> v.InfoDict)
                                    let args = {
                                        Url = job.Url
                                        SavePath = job.SavePath
                                        ExternalId = externalId
                                        Title = infoDict |> Option.bind (fun i -> i.Title)
                                        Width = infoDict |> Option.bind (fun i -> i.Width)
                                        Height = infoDict |> Option.bind (fun i -> i.Height)
                                    }
                                    tgService.PostVideo(args)
                                    postCheck()
                                    return! loop jobQueue None

                                | Error e ->
                                    Logging.logger.Error(
                                        "Failed to receive video from youtube client, job = {job}, message = {message}",
                                        externalId,
                                        e.Message)
                                    Logging.logger.Information("Deleting file path = {path}", job.SavePath)
                                    File.Delete(job.SavePath)
                                    return! loop jobQueue None

                                | _ ->
                                    Logging.logger.Information(
                                        "Waiting for job to complete, job = {job}",
                                        externalId)
                                    postCheck()
                                    return! loop jobQueue current

                        | None ->
                            return! loop jobQueue None
                }
            loop (Queue()) None
        )

    let createService youtubeDlClient tgService =
        let inbox = createServiceInbox youtubeDlClient tgService
        { new IYoutubeDlService with
            member this.AddJob(url) =
                let tcs = TaskCompletionSource<_>()
                inbox.Post(AddJob(url, tcs))
                tcs.Task |> Async.AwaitTask }