using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using MongoDB.Driver;
using QuestionsApi.Models;
using QuestionsApi.Services;

namespace QuestionsApi.Controllers;

[ApiController]
[Route("api/[controller]")]
public class QuestionsController : ControllerBase
{
    private readonly QuestionStore _questions;

    public QuestionsController(QuestionStore questions)
    {
        _questions = questions;
    }

    [HttpGet("systems")]
    [Authorize(Roles = "USER,SUPER")]
    public async Task<IActionResult> Systems()
    {
        var systems = await _questions.GetSystemsAsync(User.IsInRole("SUPER"));
        return Ok(systems);
    }

    [HttpPost("search")]
    [Authorize(Roles = "USER,SUPER")]
    public async Task<IActionResult> Search([FromBody] QuestionSearchRequest req)
    {
        var questions = await _questions.SearchAsync(req, User.IsInRole("SUPER"));
        return Ok(questions.Select(QuestionResponse.FromModel).ToList());
    }

    [HttpGet("{id}")]
    [Authorize(Roles = "USER,SUPER")]
    public async Task<IActionResult> Get(string id)
    {
        var question = await _questions.GetByIdAsync(id);
        if (question is null || (!question.IsPublished && !User.IsInRole("SUPER")))
            return NotFound();

        return Ok(QuestionResponse.FromModel(question));
    }

    [HttpPost]
    [Authorize(Roles = "SUPER")]
    public async Task<IActionResult> Create([FromBody] UpsertQuestionRequest req)
    {
        var validation = ValidateQuestion(req);
        if (validation is not null)
            return BadRequest(validation);

        var created = await _questions.CreateAsync(req);
        if (created is null)
            return Conflict("Question externalId already exists");

        return Ok(QuestionResponse.FromModel(created));
    }

    [HttpPost("bulk")]
    [Authorize(Roles = "SUPER")]
    public async Task<IActionResult> BulkUpsert([FromBody] BulkUpsertQuestionsRequest req)
    {
        if (req.Questions.Count == 0)
            return BadRequest("questions required");

        foreach (var question in req.Questions)
        {
            var validation = ValidateQuestion(question);
            if (validation is not null)
                return BadRequest($"{question.ExternalId}: {validation}");
        }

        var upserted = await _questions.UpsertManyByExternalIdAsync(req.Questions);
        return Ok(new { upserted });
    }

    [HttpPut("{id}")]
    [Authorize(Roles = "SUPER")]
    public async Task<IActionResult> Update(string id, [FromBody] UpsertQuestionRequest req)
    {
        var validation = ValidateQuestion(req);
        if (validation is not null)
            return BadRequest(validation);

        try
        {
            var updated = await _questions.UpdateAsync(id, req);
            if (updated is null)
                return NotFound();

            return Ok(QuestionResponse.FromModel(updated));
        }
        catch (MongoWriteException ex) when (ex.WriteError.Category == ServerErrorCategory.DuplicateKey)
        {
            return Conflict("Question externalId already exists");
        }
    }

    [HttpDelete("{id}")]
    [Authorize(Roles = "SUPER")]
    public async Task<IActionResult> Delete(string id)
    {
        var deleted = await _questions.DeleteAsync(id);
        if (!deleted)
            return NotFound();

        return Ok("Deleted");
    }

    private static string? ValidateQuestion(UpsertQuestionRequest req)
    {
        if (string.IsNullOrWhiteSpace(req.ExternalId))
            return "externalId required";
        if (string.IsNullOrWhiteSpace(req.Stem))
            return "stem required";
        if (string.IsNullOrWhiteSpace(req.LeadIn))
            return "leadIn required";
        if (req.Choices.Count < 2)
            return "at least two choices required";
        if (string.IsNullOrWhiteSpace(req.CorrectChoiceId))
            return "correctChoiceId required";
        if (!req.Choices.Any(c => c.Id == req.CorrectChoiceId))
            return "correctChoiceId must match a choice id";
        if (string.IsNullOrWhiteSpace(req.Explanation))
            return "explanation required";
        if (string.IsNullOrWhiteSpace(req.System))
            return "system required";
        if (string.IsNullOrWhiteSpace(req.Discipline))
            return "discipline required";
        if (req.Difficulty is < 1 or > 5)
            return "difficulty must be between 1 and 5";

        return null;
    }
}