using System.ComponentModel;
using ErsatzTV.Application.MediaCollections;
using ErsatzTV.Application.MediaItems;
using ErsatzTV.Application.Search;
using ErsatzTV.Application.Search.Queries;
using ErsatzTV.Core;
using ErsatzTV.Core.Api.Scheduling;
using ErsatzTV.Core.Api.Search;
using ErsatzTV.Extensions;
using MediatR;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace ErsatzTV.Controllers.Api;

[ApiController]
public class SearchController(IMediator mediator) : ControllerBase
{
    private const int MaxPageSize = 100;

    // all-items returns bare ids (cheap), so it tolerates a larger page than the item-returning
    // /search endpoint; the clamp still bounds one response to <= 10 kinds * MaxAllItemsPageSize ids
    // so a broad query can't materialize the whole index in one request (issue #293).
    private const int DefaultAllItemsPageSize = 500;
    private const int MaxAllItemsPageSize = 1000;

    // Upper-bound the page number so pageNum * pageSize (the search skip) can't overflow int and 500 —
    // no legitimate client pages past this, and it keeps skip + limit inside int range at MaxAllItemsPageSize.
    private const int MaxAllItemsPageNum = 2_000_000;

    [HttpGet("/api/v1/search", Name = "Search")]
    [Tags("Search")]
    [EndpointSummary("Search library items across all media kinds")]
    [EndpointGroupName("general")]
    [ProducesResponseType(typeof(SearchResultsResponseModel), StatusCodes.Status200OK)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status422UnprocessableEntity)]
    public async Task<IActionResult> Search(
        [FromQuery] string query = "",
        [FromQuery]
        [Description("0-based page index: the first page is 0, not 1. A negative value is clamped to 0.")]
        int pageNum = 0,
        [FromQuery]
        [Description("Rows per page (default 50); capped at 100 for this endpoint. The page offset is derived from the effective (capped) size, so a larger value narrows the page instead of widening the offset.")]
        int pageSize = 50,
        CancellationToken cancellationToken = default)
    {
        if (string.IsNullOrWhiteSpace(query))
        {
            return BaseError.New("A non-empty query is required").ToErrorResult();
        }

        int clampedPageNum = Math.Max(0, pageNum);
        int clampedPageSize = Math.Clamp(pageSize, 1, MaxPageSize);
        SearchResultsResponseModel result = await mediator.Send(
            new GetSearchResults(query, clampedPageNum, clampedPageSize),
            cancellationToken);
        return new OkObjectResult(result);
    }

    [HttpGet("/api/v1/search/all-items", Name = "SearchAllItems")]
    [Tags("Search")]
    [EndpointSummary("Search library items across all media kinds and return raw id lists")]
    [EndpointDescription(
        "Returns matching item ids, grouped by media kind, one clamped page per kind plus per-kind " +
        "total counts. Used by the SPA's \"add all to collection/playlist\" flow, which pages to " +
        "completeness. Paging bounds a broad query so it can't materialize the whole index in one " +
        "request (issue #293).")]
    [EndpointGroupName("general")]
    [ProducesResponseType(typeof(SearchResultAllItemsResponseModel), StatusCodes.Status200OK)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status422UnprocessableEntity)]
    public async Task<IActionResult> SearchAllItems(
        [FromQuery] string query = "",
        [FromQuery]
        [Description("0-based page index: the first page is 0, not 1. A negative value is clamped to 0. Unlike the other paged endpoints this one is also bounded ABOVE, at 2000000, so that pageNum * pageSize cannot overflow; a larger value is clamped down to that maximum rather than rejected.")]
        int pageNum = 0,
        [FromQuery]
        [Description("Rows per page (default 500); capped at 1000 for this endpoint. The page offset is derived from the effective (capped) size, so a larger value narrows the page instead of widening the offset.")]
        int pageSize = DefaultAllItemsPageSize,
        CancellationToken cancellationToken = default)
    {
        if (string.IsNullOrWhiteSpace(query))
        {
            return BaseError.New("A non-empty query is required").ToErrorResult();
        }

        int clampedPageNum = Math.Clamp(pageNum, 0, MaxAllItemsPageNum);
        int clampedPageSize = Math.Clamp(pageSize, 1, MaxAllItemsPageSize);
        SearchResultAllItemsViewModel result = await mediator.Send(
            new QuerySearchIndexAllItems(query, clampedPageNum, clampedPageSize),
            cancellationToken);
        return new OkObjectResult(Project(result));
    }

    [HttpGet("/api/v1/search/collections", Name = "SearchCollections")]
    [Tags("Search")]
    [EndpointSummary("Search collections by name")]
    [EndpointDescription("Returns matching collections as {id, name} options for scheduling editors.")]
    [EndpointGroupName("general")]
    [ProducesResponseType(typeof(List<SchedulingPickerOptionResponseModel>), StatusCodes.Status200OK)]
    public async Task<List<SchedulingPickerOptionResponseModel>> SearchCollections(
        [FromQuery] string query = "",
        CancellationToken cancellationToken = default)
    {
        List<MediaCollectionViewModel> results = await mediator.Send(
            new SearchCollections(query ?? string.Empty),
            cancellationToken);
        return results.Map(c => new SchedulingPickerOptionResponseModel(c.Id, c.Name)).ToList();
    }

    [HttpGet("/api/v1/search/television-shows", Name = "SearchTelevisionShows")]
    [Tags("Search")]
    [EndpointSummary("Search television shows by name")]
    [EndpointDescription("Returns matching television shows as {id, name} options for scheduling editors.")]
    [EndpointGroupName("general")]
    [ProducesResponseType(typeof(List<SchedulingPickerOptionResponseModel>), StatusCodes.Status200OK)]
    public async Task<List<SchedulingPickerOptionResponseModel>> SearchTelevisionShows(
        [FromQuery] string query = "",
        CancellationToken cancellationToken = default)
    {
        List<NamedMediaItemViewModel> results = await mediator.Send(
            new SearchTelevisionShows(query ?? string.Empty),
            cancellationToken);
        return results.Map(s => new SchedulingPickerOptionResponseModel(s.MediaItemId, s.Name)).ToList();
    }

    [HttpGet("/api/v1/search/television-seasons", Name = "SearchTelevisionSeasons")]
    [Tags("Search")]
    [EndpointSummary("Search television seasons by name")]
    [EndpointDescription("Returns matching television seasons as {id, name} options for scheduling editors.")]
    [EndpointGroupName("general")]
    [ProducesResponseType(typeof(List<SchedulingPickerOptionResponseModel>), StatusCodes.Status200OK)]
    public async Task<List<SchedulingPickerOptionResponseModel>> SearchTelevisionSeasons(
        [FromQuery] string query = "",
        CancellationToken cancellationToken = default)
    {
        List<NamedMediaItemViewModel> results = await mediator.Send(
            new SearchTelevisionSeasons(query ?? string.Empty),
            cancellationToken);
        return results.Map(s => new SchedulingPickerOptionResponseModel(s.MediaItemId, s.Name)).ToList();
    }

    [HttpGet("/api/v1/search/smart-collections", Name = "SearchSmartCollections")]
    [Tags("Search")]
    [EndpointSummary("Search smart collections by name")]
    [EndpointDescription("Returns matching smart collections as {id, name} options for scheduling editors.")]
    [EndpointGroupName("general")]
    [ProducesResponseType(typeof(List<SchedulingPickerOptionResponseModel>), StatusCodes.Status200OK)]
    public async Task<List<SchedulingPickerOptionResponseModel>> SearchSmartCollections(
        [FromQuery] string query = "",
        CancellationToken cancellationToken = default)
    {
        List<SmartCollectionViewModel> results = await mediator.Send(
            new SearchSmartCollections(query ?? string.Empty),
            cancellationToken);
        return results.Map(c => new SchedulingPickerOptionResponseModel(c.Id, c.Name)).ToList();
    }

    [HttpGet("/api/v1/search/artists", Name = "SearchArtists")]
    [Tags("Search")]
    [EndpointSummary("Search artists by name")]
    [EndpointDescription("Returns matching artists as {id, name} options for scheduling editors.")]
    [EndpointGroupName("general")]
    [ProducesResponseType(typeof(List<SchedulingPickerOptionResponseModel>), StatusCodes.Status200OK)]
    public async Task<List<SchedulingPickerOptionResponseModel>> SearchArtists(
        [FromQuery] string query = "",
        CancellationToken cancellationToken = default)
    {
        List<NamedMediaItemViewModel> results = await mediator.Send(
            new SearchArtists(query ?? string.Empty),
            cancellationToken);
        return results.Map(a => new SchedulingPickerOptionResponseModel(a.MediaItemId, a.Name)).ToList();
    }

    [HttpGet("/api/v1/search/multi-collections", Name = "SearchMultiCollections")]
    [Tags("Search")]
    [EndpointSummary("Search multi collections by name")]
    [EndpointDescription("Returns matching multi collections as {id, name} options for scheduling editors.")]
    [EndpointGroupName("general")]
    [ProducesResponseType(typeof(List<SchedulingPickerOptionResponseModel>), StatusCodes.Status200OK)]
    public async Task<List<SchedulingPickerOptionResponseModel>> SearchMultiCollections(
        [FromQuery] string query = "",
        CancellationToken cancellationToken = default)
    {
        List<MultiCollectionViewModel> results = await mediator.Send(
            new SearchMultiCollections(query ?? string.Empty),
            cancellationToken);
        return results.Map(c => new SchedulingPickerOptionResponseModel(c.Id, c.Name)).ToList();
    }

    [HttpGet("/api/v1/search/fields", Name = "GetSearchFields")]
    [Tags("Search")]
    [EndpointSummary("List the filterable fields for the visual rule builder")]
    [EndpointDescription(
        "Returns the curated catalog of searchable fields (name, friendly label, type, UI group, and " +
        "allowed values for enum fields). Drives the SmartCollection rule builder and is introspectable by MCP.")]
    [EndpointGroupName("general")]
    [ProducesResponseType(typeof(List<SearchFieldResponseModel>), StatusCodes.Status200OK)]
    public Task<List<SearchFieldResponseModel>> GetSearchFields(CancellationToken cancellationToken) =>
        mediator.Send(new GetSearchFieldCatalog(), cancellationToken);

    [HttpGet("/api/v1/search/fields/{name}/values", Name = "GetSearchFieldValues")]
    [Tags("Search")]
    [EndpointSummary("List distinct database values for a text search field")]
    [EndpointDescription(
        "Returns distinct whole values from the database for the given text field, filtered by an " +
        "optional case-insensitive prefix. Powers the visual rule builder's facet-value typeahead. " +
        "404 when the field is unknown, is not a text field, or is a text field with no distinct-value " +
        "source. The final filter, dedup and ordering applied to the response are ordinal and not " +
        "culture-dependent; note that fields sourced by a plain database query are additionally " +
        "pre-filtered by the database collation first, which on SQLite is ASCII-only. The list-valued " +
        "music fields (artist, album_artist) are bounded best-effort: the server reads a bounded number " +
        "of song rows per request, so a library larger than that bound may yield a subset of the matches.")]
    [EndpointGroupName("general")]
    [ProducesResponseType(typeof(SearchFieldValuesResponseModel), StatusCodes.Status200OK)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status404NotFound)]
    public async Task<IActionResult> GetSearchFieldValues(
        [FromRoute] string name,
        [FromQuery] string q = "",
        [FromQuery] int limit = 50,
        CancellationToken cancellationToken = default)
    {
        Option<SearchFieldValuesResponseModel> result = await mediator.Send(
            new GetSearchFieldValues(name, q ?? string.Empty, limit),
            cancellationToken);
        return result.ToGetResult();
    }

    private static SearchResultAllItemsResponseModel Project(SearchResultAllItemsViewModel vm) =>
        new(
            vm.MovieIds,
            vm.ShowIds,
            vm.SeasonIds,
            vm.EpisodeIds,
            vm.ArtistIds,
            vm.MusicVideoIds,
            vm.OtherVideoIds,
            vm.SongIds,
            vm.ImageIds,
            vm.RemoteStreamIds,
            new SearchResultAllItemsTotalsResponseModel(
                vm.Totals.MovieCount,
                vm.Totals.ShowCount,
                vm.Totals.SeasonCount,
                vm.Totals.EpisodeCount,
                vm.Totals.ArtistCount,
                vm.Totals.MusicVideoCount,
                vm.Totals.OtherVideoCount,
                vm.Totals.SongCount,
                vm.Totals.ImageCount,
                vm.Totals.RemoteStreamCount));
}