using System.Globalization;
using System.Text.Json;
using Microsoft.Extensions.Options;
using TeleWave.Application.Common.Interfaces;
using TeleWave.Application.Metadata;

namespace TeleWave.Infrastructure.Metadata;

/// <summary>Провайдер метаданных OMDb (omdbapi.com, данные IMDb). Требует API-ключ.</summary>
public sealed class OmdbMetadataProvider(
    IHttpClientFactory httpFactory,
    IOptions<MetadataOptions> options
) : IMetadataProvider
{
    private readonly OmdbOptions _omdb = options.Value.Omdb;

    public string Key => "omdb";

    public async Task<IReadOnlyList<MetadataCandidate>> SearchShowsAsync(
        string query,
        CancellationToken cancellationToken
    )
    {
        var url =
            $"{_omdb.BaseUrl}/?apikey={_omdb.ApiKey}&type=series&s={Uri.EscapeDataString(query)}";
        using var doc = await GetJsonAsync(url, cancellationToken);
        if (!doc.RootElement.TryGetProperty("Search", out var search))
            return [];

        var list = new List<MetadataCandidate>();
        foreach (var item in search.EnumerateArray())
        {
            var id = Clean(GetString(item, "imdbID"));
            if (id is null)
                continue;
            list.Add(
                new MetadataCandidate(
                    id,
                    Clean(GetString(item, "Title")) ?? "—",
                    YearFrom(GetString(item, "Year")),
                    null,
                    Clean(GetString(item, "Poster"))
                )
            );
        }
        return list;
    }

    public async Task<ShowMetadata?> GetShowAsync(
        string externalId,
        CancellationToken cancellationToken
    )
    {
        var url = $"{_omdb.BaseUrl}/?apikey={_omdb.ApiKey}&i={Uri.EscapeDataString(externalId)}";
        using var doc = await TryGetJsonAsync(url, cancellationToken);
        if (doc is null || !IsResponseTrue(doc.RootElement))
            return null;
        var root = doc.RootElement;
        return new ShowMetadata(
            externalId,
            Clean(GetString(root, "Title")) ?? "—",
            YearFrom(GetString(root, "Year")),
            Clean(GetString(root, "Plot")),
            Clean(GetString(root, "Poster"))
        );
    }

    public async Task<EpisodeMetadata?> GetEpisodeAsync(
        string externalId,
        int season,
        int episode,
        CancellationToken cancellationToken
    )
    {
        var url =
            $"{_omdb.BaseUrl}/?apikey={_omdb.ApiKey}&i={Uri.EscapeDataString(externalId)}"
            + $"&Season={season}&Episode={episode}";
        using var doc = await TryGetJsonAsync(url, cancellationToken);
        if (doc is null || !IsResponseTrue(doc.RootElement))
            return null;
        var root = doc.RootElement;
        return new EpisodeMetadata(
            Clean(GetString(root, "Title")) ?? "—",
            Clean(GetString(root, "Plot")),
            Clean(GetString(root, "Poster")),
            DateFrom(GetString(root, "Released"))
        );
    }

    public async Task<int?> GetSeasonEpisodeCountAsync(
        string externalId,
        int season,
        CancellationToken cancellationToken
    )
    {
        var url =
            $"{_omdb.BaseUrl}/?apikey={_omdb.ApiKey}&i={Uri.EscapeDataString(externalId)}&Season={season}";
        using var doc = await TryGetJsonAsync(url, cancellationToken);
        if (
            doc is null
            || !IsResponseTrue(doc.RootElement)
            || !doc.RootElement.TryGetProperty("Episodes", out var episodes)
            || episodes.ValueKind != JsonValueKind.Array
        )
            return null;
        return episodes.GetArrayLength();
    }

    /// <summary>GET+parse; бросает при не-2xx/сетевой ошибке (для поиска — чтобы показать сбой).</summary>
    private async Task<JsonDocument> GetJsonAsync(string url, CancellationToken cancellationToken)
    {
        var client = httpFactory.CreateClient("metadata");
        using var response = await client.GetAsync(url, cancellationToken);
        response.EnsureSuccessStatusCode();
        var stream = await response.Content.ReadAsStreamAsync(cancellationToken);
        return await JsonDocument.ParseAsync(stream, cancellationToken: cancellationToken);
    }

    /// <summary>Как GetJsonAsync, но глотает ошибки в null (для get/episode — деградируем мягко).</summary>
    private async Task<JsonDocument?> TryGetJsonAsync(
        string url,
        CancellationToken cancellationToken
    )
    {
        try
        {
            return await GetJsonAsync(url, cancellationToken);
        }
        catch (Exception ex)
            when (ex is HttpRequestException or JsonException or TaskCanceledException)
        {
            return null;
        }
    }

    private static bool IsResponseTrue(JsonElement root) =>
        GetString(root, "Response") is { } r
        && r.Equals("True", StringComparison.OrdinalIgnoreCase);

    private static string? GetString(JsonElement el, string name) =>
        el.TryGetProperty(name, out var v) && v.ValueKind == JsonValueKind.String
            ? v.GetString()
            : null;

    /// <summary>OMDb отдаёт «N/A» вместо отсутствующих значений — приводим к null.</summary>
    private static string? Clean(string? value) =>
        string.IsNullOrWhiteSpace(value) || value == "N/A" ? null : value;

    private static int? YearFrom(string? year)
    {
        if (year is { Length: >= 4 } && int.TryParse(year.AsSpan(0, 4), out var y))
            return y;
        return null;
    }

    private static DateOnly? DateFrom(string? released) =>
        DateTime.TryParse(released, CultureInfo.InvariantCulture, DateTimeStyles.None, out var dt)
            ? DateOnly.FromDateTime(dt)
            : null;
}