using System.Text.Json;
using JobTrackerApi.Data;
using JobTrackerApi.Models;
using JobTrackerApi.Services;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Caching.Memory;

namespace JobTrackerApi.Controllers;

[ApiController]
[Route("api/job-discovery")]
[Authorize(AuthenticationSchemes = "local")]
public sealed class JobDiscoveryController : ControllerBase
{
    private readonly IJobDiscoverySearchService _discovery;
    private readonly SavedJobSearchRunner? _savedSearchRunner;
    private readonly JobTrackerContext? _db;
    private readonly ICurrentUserService? _currentUser;

    public JobDiscoveryController(
        IHttpClientFactory clients,
        IConfiguration configuration,
        IMemoryCache cache,
        JobTrackerContext? db = null,
        ICurrentUserService? currentUser = null,
        IJobDiscoverySearchService? discovery = null,
        SavedJobSearchRunner? savedSearchRunner = null)
    {
        _discovery = discovery ?? new NavJobDiscoverySearchService(clients, configuration, cache, TimeProvider.System);
        _savedSearchRunner = savedSearchRunner;
        _db = db;
        _currentUser = currentUser;
    }

    [HttpGet("search")]
    public async Task<ActionResult<IReadOnlyList<DiscoveredJob>>> Search([FromQuery] string? q, [FromQuery] string? location, CancellationToken cancellationToken)
    {
        try
        {
            return Ok(await _discovery.SearchAsync(q, location, cancellationToken));
        }
        catch (Exception ex) when (ex is HttpRequestException or JsonException or InvalidOperationException)
        {
            return Problem("NAV job discovery is temporarily unavailable.", statusCode: StatusCodes.Status502BadGateway);
        }
    }

    [HttpGet("saved-searches")]
    public async Task<ActionResult<IReadOnlyList<SavedSearchDto>>> ListSavedSearches(CancellationToken cancellationToken)
    {
        if (!TryGetPersistence(out var db, out var owner)) return Unauthorized();
        var searches = await db.SavedJobSearches.AsNoTracking().Include(x => x.Results)
            .Where(x => x.OwnerUserId == owner).OrderByDescending(x => x.UpdatedAtUtc).ToListAsync(cancellationToken);
        return Ok(searches.Select(ToDto).ToList());
    }

    [HttpPost("saved-searches")]
    public async Task<ActionResult<SavedSearchDto>> CreateSavedSearch([FromBody] SavedSearchRequest request, CancellationToken cancellationToken)
    {
        if (!TryGetPersistence(out var db, out var owner)) return Unauthorized();
        var name = request.Name?.Trim() ?? "";
        var query = request.Query?.Trim() ?? "";
        var location = request.Location?.Trim() ?? "";
        if (name.Length is < 1 or > 255 || query.Length > 500 || location.Length > 255)
            return ValidationProblem("Provide a name up to 255 characters and valid search filters.");

        var now = DateTimeOffset.UtcNow;
        var search = new SavedJobSearch { OwnerUserId = owner, Name = name, Query = query, Location = location, CreatedAtUtc = now, UpdatedAtUtc = now };
        db.SavedJobSearches.Add(search);
        await db.SaveChangesAsync(cancellationToken);
        return CreatedAtAction(nameof(ListSavedSearches), ToDto(search));
    }

    [HttpDelete("saved-searches/{id:int}")]
    public async Task<IActionResult> DeleteSavedSearch(int id, CancellationToken cancellationToken)
    {
        if (!TryGetPersistence(out var db, out var owner)) return Unauthorized();
        var search = await db.SavedJobSearches.FirstOrDefaultAsync(x => x.Id == id && x.OwnerUserId == owner, cancellationToken);
        if (search is null) return NotFound();
        db.SavedJobSearches.Remove(search);
        await db.SaveChangesAsync(cancellationToken);
        return NoContent();
    }

    [HttpPatch("saved-searches/{id:int}")]
    public async Task<ActionResult<SavedSearchDto>> UpdateSavedSearch(int id, [FromBody] UpdateSavedSearchRequest request, CancellationToken cancellationToken)
    {
        if (!TryGetPersistence(out var db, out var owner)) return Unauthorized();
        var search = await db.SavedJobSearches.Include(x => x.Results)
            .FirstOrDefaultAsync(x => x.Id == id && x.OwnerUserId == owner, cancellationToken);
        if (search is null) return NotFound();
        search.IsActive = request.IsActive;
        search.UpdatedAtUtc = DateTimeOffset.UtcNow;
        await db.SaveChangesAsync(cancellationToken);
        return Ok(ToDto(search));
    }

    [HttpPost("saved-searches/{id:int}/run")]
    public async Task<ActionResult<SavedSearchRunDto>> RunSavedSearch(int id, CancellationToken cancellationToken)
    {
        if (!TryGetPersistence(out var db, out var owner)) return Unauthorized();
        var search = await db.SavedJobSearches.Include(x => x.Results).FirstOrDefaultAsync(x => x.Id == id && x.OwnerUserId == owner, cancellationToken);
        if (search is null) return NotFound();

        try
        {
            var runner = _savedSearchRunner ?? new SavedJobSearchRunner(db, _discovery, TimeProvider.System);
            var run = await runner.RunAsync(search, cancellationToken);
            await db.SaveChangesAsync(cancellationToken);
            return Ok(new SavedSearchRunDto(ToDto(search), run.Jobs.Select(item => new SavedSearchJobDto(item.Job, item.IsNew, item.IsDismissed)).ToList()));
        }
        catch (Exception ex) when (ex is HttpRequestException or JsonException or InvalidOperationException)
        {
            return Problem("NAV job discovery is temporarily unavailable.", statusCode: StatusCodes.Status502BadGateway);
        }
    }

    [HttpPatch("saved-searches/{id:int}/results/{externalJobId}/dismiss")]
    public async Task<IActionResult> DismissSavedSearchResult(int id, string externalJobId, [FromBody] DismissRequest request, CancellationToken cancellationToken)
    {
        if (!TryGetPersistence(out var db, out var owner)) return Unauthorized();
        var result = await db.SavedJobSearchResults
            .FirstOrDefaultAsync(x => x.SavedJobSearchId == id && x.ExternalJobId == externalJobId && x.SavedJobSearch!.OwnerUserId == owner, cancellationToken);
        if (result is null) return NotFound();
        result.IsDismissed = request.IsDismissed;
        await db.SaveChangesAsync(cancellationToken);
        return NoContent();
    }

    private bool TryGetPersistence(out JobTrackerContext db, out string owner)
    {
        db = _db!;
        owner = _currentUser?.UserId ?? "";
        return db is not null && owner.Length > 0;
    }

    public sealed record SavedSearchRequest(string? Name, string? Query, string? Location);
    public sealed record UpdateSavedSearchRequest(bool IsActive);
    public sealed record DismissRequest(bool IsDismissed);
    public sealed record SavedSearchDto(int Id, string Name, string Query, string Location, bool IsActive, DateTimeOffset? LastRunAtUtc, int ResultCount, int DismissedCount);
    public sealed record SavedSearchJobDto(DiscoveredJob Job, bool IsNew, bool IsDismissed);
    public sealed record SavedSearchRunDto(SavedSearchDto Search, IReadOnlyList<SavedSearchJobDto> Jobs);
    private static SavedSearchDto ToDto(SavedJobSearch search) => new(search.Id, search.Name, search.Query, search.Location, search.IsActive, search.LastRunAtUtc, search.Results.Count, search.Results.Count(x => x.IsDismissed));
}