using System.Net;
using System.Net.Http;
using System.Net.Http.Json;
using System.Text.Json;
using EnvelopeGenerator.Application.Common.Dto;

namespace EnvelopeGenerator.Server.Client.Services;

public class DocumentService(IHttpClientFactory httpClientFactory)
{
    private static readonly JsonSerializerOptions _jsonOptions = new(JsonSerializerDefaults.Web);

    /// <summary>
    /// Fetches the PDF bytes for the given envelope key from the API.
    /// Throws HttpRequestException on failure with appropriate status code.
    /// </summary>
    /// <exception cref="HttpRequestException">Thrown when the API request fails.</exception>
    public async Task<byte[]?> GetDocumentAsync(string envelopeKey, CancellationToken cancel = default)
    {
        using var http = httpClientFactory.CreateClient("EnvelopeGenerator.Server");
        var response = await http.GetAsync($"/api/Document/{Uri.EscapeDataString(envelopeKey)}", cancel);

        if (!response.IsSuccessStatusCode)
        {
            var statusCode = (int)response.StatusCode;
            var reasonPhrase = response.ReasonPhrase ?? "Unknown error";
            throw new HttpRequestException(
                $"Failed to load document. Status: {statusCode} ({reasonPhrase})",
                null,
                response.StatusCode);
        }

        var bytes = await response.Content.ReadAsByteArrayAsync(cancel);
        return bytes;
    }

    /// <summary>
    /// Fetches sender document details (including signature elements) by envelope id.
    /// Uses GET /api/Document/details?EnvelopeId={envelopeId}.
    /// </summary>
    public async Task<DocumentDto?> GetSenderDocumentDetailsByEnvelopeIdAsync(int envelopeId, CancellationToken cancel = default)
    {
        using var http = httpClientFactory.CreateClient("EnvelopeGenerator.Server");
        var detailsResponse = await http.GetAsync($"/api/Document/details?EnvelopeId={envelopeId}", cancel);

        if (!detailsResponse.IsSuccessStatusCode)
        {
            var statusCode = (int)detailsResponse.StatusCode;
            var reasonPhrase = detailsResponse.ReasonPhrase ?? "Unknown error";
            throw new HttpRequestException(
                $"Failed to load sender document details. Status: {statusCode} ({reasonPhrase})",
                null,
                detailsResponse.StatusCode);
        }

        var details = await detailsResponse.Content.ReadFromJsonAsync<DocumentDetailsDto>(_jsonOptions, cancel)
            ?? throw new HttpRequestException("Failed to deserialize sender document details response.");

        var bytesResponse = await http.GetAsync($"/api/Document?EnvelopeId={envelopeId}", cancel);

        if (!bytesResponse.IsSuccessStatusCode)
        {
            var statusCode = (int)bytesResponse.StatusCode;
            var reasonPhrase = bytesResponse.ReasonPhrase ?? "Unknown error";
            throw new HttpRequestException(
                $"Failed to load sender document bytes. Status: {statusCode} ({reasonPhrase})",
                null,
                bytesResponse.StatusCode);
        }

        var byteData = await bytesResponse.Content.ReadAsByteArrayAsync(cancel);

        return new DocumentDto(byteData, details);
    }

    /// <summary>
    /// Fetches sender document bytes by envelope id.
    /// Uses GET /api/Document?EnvelopeId={envelopeId}.
    /// </summary>
    public async Task<byte[]?> GetSenderDocumentBytesByEnvelopeIdAsync(int envelopeId, CancellationToken cancel = default)
    {
        using var http = httpClientFactory.CreateClient("EnvelopeGenerator.Server");
        var response = await http.GetAsync($"/api/Document?EnvelopeId={envelopeId}", cancel);

        if (!response.IsSuccessStatusCode)
        {
            var statusCode = (int)response.StatusCode;
            var reasonPhrase = response.ReasonPhrase ?? "Unknown error";
            throw new HttpRequestException(
                $"Failed to load sender document bytes. Status: {statusCode} ({reasonPhrase})",
                null,
                response.StatusCode);
        }

        return await response.Content.ReadAsByteArrayAsync(cancel);
    }
}