using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using QuestionsApi.Models;
using QuestionsApi.Services;
using System.Security.Claims;

namespace QuestionsApi.Controllers;

[ApiController]
[Route("api/review-queue")]
[Authorize(Roles = "USER,SUPER")]
public sealed class ReviewQueueController(
    ReviewQueueStore queue,
    QuestionStore questions,
    AnswerStatisticsStore statistics,
    RatingStore ratings,
    QuestionBookmarkStore bookmarks,
    CreditStore credits,
    MasteryAwardService masteryAwards,
    StudySessionStore studySessions,
    DailyMissionStore dailyMissions) : ControllerBase
{
    [HttpPost("next")]
    public async Task<IActionResult> Next([FromBody] ReviewQueueNextRequest req)
    {
        var userId = UserId();
        if (string.IsNullOrWhiteSpace(userId)) return Unauthorized();
        await queue.EnsureUserQueueAsync(userId);
        ReviewQueueItem? item;
        try { item = await queue.GetRandomPendingAsync(userId, req.ExcludeExternalIds, req.Step3System); }
        catch (ArgumentException exception) { return BadRequest(exception.Message); }
        if (item is null)
            return Ok(new ReviewQueueNextResponse { PendingCount = checked((int)await queue.CountPendingAsync(userId, req.Step3System)) });

        var question = await questions.GetByExternalIdAsync(item.QuestionExternalId);
        if (question is null || !question.IsPublished) return NotFound();
        var percentages = await statistics.GetPercentagesForQuestionAsync(question.ExternalId);
        var response = QuestionResponse.FromModel(
            question,
            percentages,
            await ratings.GetQuestionEloAsync(question.ExternalId),
            req.SupportsChoicePools);
        response.IsBookmarked = await bookmarks.IsBookmarkedAsync(userId, question.ExternalId);
        return Ok(new ReviewQueueNextResponse
        {
            Question = response,
            Cycle = item.Cycle,
            PendingCount = checked((int)await queue.CountPendingAsync(userId, req.Step3System))
        });
    }

    [HttpPost("attempts")]
    public async Task<IActionResult> RecordAttempt([FromBody] ReviewQueueAttemptRequest req)
    {
        var userId = UserId();
        if (string.IsNullOrWhiteSpace(userId)) return Unauthorized();
        if (!Guid.TryParse(req.ClientAttemptId, out _)) return BadRequest("clientAttemptId must be a UUID");
        if (string.IsNullOrWhiteSpace(req.QuestionExternalId)) return BadRequest("questionExternalId required");
        if (req.Cycle < 1) return BadRequest("cycle must be positive");
        if (string.IsNullOrWhiteSpace(req.ChoiceId)) return BadRequest("choiceId required");

        var question = await questions.GetByExternalIdAsync(req.QuestionExternalId.Trim());
        if (question is null || !question.IsPublished) return NotFound();
        var choiceId = req.ChoiceId.Trim();
        if (!question.Choices.Any(choice => choice.Id == choiceId)) return BadRequest("choiceId must match a choice id");
        var presented = req.PresentedChoiceIds.Where(value => !string.IsNullOrWhiteSpace(value)).Select(value => value.Trim()).ToList();
        if (presented.Count > 0)
        {
            var validIds = question.Choices.Select(choice => choice.Id).ToHashSet(StringComparer.Ordinal);
            if (presented.Count != 5 || presented.Distinct(StringComparer.Ordinal).Count() != 5)
                return BadRequest("presentedChoiceIds must contain exactly five unique choice ids");
            if (presented.Any(value => !validIds.Contains(value))
                || !presented.Contains(choiceId, StringComparer.Ordinal)
                || !presented.Contains(question.CorrectChoiceId, StringComparer.Ordinal))
                return BadRequest("presentedChoiceIds must include valid selected and correct choices");
        }

        await masteryAwards.PrepareAsync(userId);
        var result = await queue.RecordReviewAsync(
            userId,
            req.ClientAttemptId,
            question.ExternalId,
            req.Cycle,
            choiceId,
            presented,
            choiceId == question.CorrectChoiceId,
            req.DurationSeconds);
        if (result is null) return Conflict("review cycle is no longer active");
        var awards = new List<CreditAward>();
        var delayed = false;
        if (result.Attempt.IsCorrect)
        {
            delayed = result.Item is not null
                && result.Attempt.CreatedUtc - result.Item.CreatedUtc >= TimeSpan.FromHours(24);
            var award = await credits.AwardAsync(userId, new CreditAwardRequest(
                $"review:{result.Attempt.Id}", CreditEconomy.ReviewAmount(delayed),
                delayed ? CreditReasonCodes.DelayedRecovery : CreditReasonCodes.ScheduledReview,
                delayed ? "Delayed recovery of a missed question" : "Correct scheduled review",
                "question_review", result.Attempt.Id));
            if (award.Award is not null) awards.Add(award.Award);
        }
        awards.AddRange(await masteryAwards.AwardPromotionsAsync(userId));
        StudySessionEnvelope? studySession = null;
        if (!string.IsNullOrWhiteSpace(req.StudySessionId))
            studySession = await studySessions.RecordReviewAsync(
                req.StudySessionId, userId, result.Attempt, delayed, awards);
        if (studySession?.Summary is not null)
            awards.AddRange(studySession.Summary.CoinAwards.Where(value =>
                value.ReasonCode == CreditReasonCodes.SessionGoalComplete
                && awards.All(existing => existing.ReasonCode != value.ReasonCode)));
        var missionResult = await dailyMissions.RecordReviewAsync(userId, result.Attempt);
        if (missionResult is not null) awards.AddRange(missionResult.CreditAwards);
        return Ok(new ReviewQueueAttemptResponse
        {
            QuestionExternalId = question.ExternalId,
            IsCorrect = result.Attempt.IsCorrect,
            QueueState = result.Item?.State ?? ReviewQueueStates.Pending,
            PendingCount = checked((int)await queue.CountPendingAsync(userId)),
            Credits = await credits.GetStatusAsync(userId),
            CreditAwards = awards,
            StudySessionProgress = studySession?.Progress,
            SessionSummary = studySession?.Summary,
            DailyMissions = missionResult?.State
        });
    }

    private string UserId() => User.FindFirstValue(ClaimTypes.NameIdentifier)
        ?? User.FindFirstValue(ClaimTypes.Name)
        ?? User.Identity?.Name
        ?? "";
}