using GB5Shared.DTO.Framework.Login;
using RecruitmentDAL.DTO.Application;
using RecruitmentDAL.DTO.Interview;
using RecruitmentDAL.DTO.JobOffer;
using RecruitmentDAL.DTO.JobRequisition;

namespace RecruitmentBLL.Integration
{
    /// <summary>Outcome of a call that creates/mutates something in ECP — modeled after
    /// DXPBLL.VendorPo.MmIntegrationService's Outcome pattern. Never throws out to the caller;
    /// a failed ECP call degrades to Success=false with an Error, so an ECP outage never breaks
    /// an Interview/Application save (see EcpIntegrationService's class doc comment).</summary>
    public class EcpCallOutcome
    {
        public bool Success { get; set; }
        public string? Error { get; set; }
    }

    /// <summary>Outcome of ScheduleMeetingAsync — carries the ECP-side MeetingId back so the
    /// caller can persist it onto TINTERVIEW.ECPMEETINGID.</summary>
    public class EcpMeetingScheduleOutcome : EcpCallOutcome
    {
        public int MeetingId { get; set; } = -1;
    }

    /// <summary>
    /// Cross-host HTTP integration with ECP (hosted by EngagementHost, a different process than
    /// Recruitment's HRFinanceHost) — no ProjectReference/DI injection of ECP's BLL exists or is
    /// possible across hosts (confirmed: no example anywhere in this repo of one module directly
    /// injecting another host's BLL), so every call here is a named-HttpClient POST/GET against
    /// ECP's verified FastEndpoints routes, following the exact
    /// IHttpClientFactory + "Login" header pattern used by
    /// DXPBLL.VendorPo.MmIntegrationService / PAYBLL.Integration.FinanceIntegrationService.
    ///
    /// Every method here degrades gracefully: a non-2xx response or thrown exception (timeout,
    /// DNS failure, ECP process down) is logged and returned as a failure/null result — it never
    /// throws back into InterviewBLL/ApplicationBLL, so an ECP outage never blocks an
    /// Interview/Application save.
    /// </summary>
    public interface IEcpIntegrationService
    {
        /// <summary>POSTs /Meeting/SaveMeeting for the interview, then POSTs
        /// /MeetingDetails/AddMeetingParticipant for the lead InterviewerId only — panel-member
        /// fan-out (TINTERVIEWPANEL) is a fast-follow once that entity's schema/BLL lands from a
        /// parallel task, not implemented here.</summary>
        Task<EcpMeetingScheduleOutcome> ScheduleMeetingAsync(InterviewDTO interview, LoginDTO login, CancellationToken ct);

        /// <summary>POSTs /MeetingRecording/AttachRecording — the caller must have already
        /// uploaded the recording as a TATTACHMENT and pass its id.</summary>
        Task<EcpCallOutcome> AttachInterviewRecordingAsync(int interviewId, int recordingAttachmentId, LoginDTO login, CancellationToken ct);

        /// <summary>GETs /MeetingRecording/GetRecordingTranscriptsForObject. Returns the raw JSON
        /// array (ECP's ResponseStandardDTO.Body content) so Recruitment never needs a
        /// ProjectReference to ECPDAL's RecordingTranscriptDTO; null on failure.</summary>
        Task<string?> GetInterviewRecordingsAsync(int interviewId, LoginDTO login, CancellationToken ct);

        /// <summary>POSTs /CommentThread/SaveCommentThread against the Application object.</summary>
        Task<EcpCallOutcome> PostApplicationCommentAsync(int applicationId, string commentText, List<int> mentionedUserIds, LoginDTO login, CancellationToken ct);

        /// <summary>GETs /CommentThread/GetCommentThreadTree for the Application object. Returns
        /// the raw JSON tree (ECP's ResponseStandardDTO.Body content); null on failure.</summary>
        Task<string?> GetApplicationCommentsAsync(int applicationId, LoginDTO login, CancellationToken ct);

        // ── Phase 3: Correspondence (offer/interview/rejection letters) ────────────────────
        // All four POST /Correspondence/SaveAndSendCorrespondence with the matching
        // RecruitmentCorrespondenceTypes.* CorrespondenceTypeId and a TemplateId read from
        // "Integration:CorrespondenceTemplates:*" config (an ECP TATTACHMENT id of a previously
        // uploaded .docx/.xlsx template — see SaveAndSendCorrespondence's real request shape).
        // If that TemplateId isn't configured (<=0), or the recipient email is empty, the call
        // degrades to Success=false without an HTTP round-trip — same graceful-degradation
        // contract as every other method on this interface, extended to cover "not configured yet"
        // as well as "ECP unreachable".

        /// <summary>Sends the offer letter for a newly-saved JobOffer. Merge fields are built from
        /// JobOfferDTO's own columns (CTC, ExpectedJoiningDate, OfferExpiryDate, JobPositionId as
        /// Position) — no cross-module JobPosition-title lookup is performed.</summary>
        Task<EcpCallOutcome> SendOfferLetterAsync(JobOfferDTO jobOffer, string recipientEmail, LoginDTO login, CancellationToken ct);

        /// <summary>Sends an interview scheduling notification for a newly-saved or rescheduled
        /// Interview.</summary>
        Task<EcpCallOutcome> SendInterviewInviteAsync(InterviewDTO interview, string recipientEmail, LoginDTO login, CancellationToken ct);

        /// <summary>Sends a candidate rejection letter for an Application.</summary>
        Task<EcpCallOutcome> SendRejectionLetterAsync(ApplicationDTO application, string recipientEmail, LoginDTO login, CancellationToken ct);

        /// <summary>Notifies the original JobRequisition requester (RequestedById, resolved to an
        /// email via MUSER.PRIMARYMAIL — same column CRMDAL/ECPDAL's own MUSER lookups already use)
        /// that their hire has joined — closes the loop back to whoever asked for the position.
        /// Degrades gracefully (Success=false) if RequestedById has no resolvable email.</summary>
        Task<EcpCallOutcome> NotifyRequesterOnHireAsync(JobRequisitionDTO jobRequisition, string hiredCandidateName, LoginDTO login, CancellationToken ct);
    }
}