// Jeton client_credentials puis lecture paginée des factures — .NET 6+ (HttpClient, System.Text.Json).
// client_credentials token, then paginated invoice reads — .NET 6+ (HttpClient, System.Text.Json).
using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;

public static class ClientCredentials
{
    private const string ApiBase = "https://api.tauraco.io/public/v1";
    private const string TokenUrl = "https://api.tauraco.io/oauth/token";

    public static async Task<string> GetTokenAsync(HttpClient http, string clientId, string clientSecret, string scope)
    {
        using var request = new HttpRequestMessage(HttpMethod.Post, TokenUrl)
        {
            Content = new FormUrlEncodedContent(new Dictionary<string, string>
            {
                ["grant_type"] = "client_credentials",
                ["scope"] = scope,
                ["resource"] = ApiBase,
            }),
        };
        request.Headers.Authorization = new AuthenticationHeaderValue(
            "Basic", Convert.ToBase64String(Encoding.UTF8.GetBytes($"{clientId}:{clientSecret}")));
        using var response = await http.SendAsync(request);
        using var payload = JsonDocument.Parse(await response.Content.ReadAsStringAsync());
        if (!response.IsSuccessStatusCode)
        {
            throw new InvalidOperationException($"jeton refusé : {(int)response.StatusCode} {payload.RootElement.GetProperty("error")}");
        }
        return payload.RootElement.GetProperty("access_token").GetString()!;
    }

    public static async Task Main()
    {
        using var http = new HttpClient();
        var token = await GetTokenAsync(http, Environment.GetEnvironmentVariable("TAURACO_CLIENT_ID")!,
            Environment.GetEnvironmentVariable("TAURACO_CLIENT_SECRET")!, "invoices:read");
        http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
        string? cursor = null;
        do
        {
            var url = $"{ApiBase}/invoices?status=PAID&limit=100" + (cursor is null ? "" : $"&cursor={Uri.EscapeDataString(cursor)}");
            using var page = JsonDocument.Parse(await http.GetStringAsync(url));
            foreach (var invoice in page.RootElement.GetProperty("data").EnumerateArray())
            {
                // Montants : chaînes décimales en unités majeures, à lire en decimal, jamais en double.
                Console.WriteLine($"{invoice.GetProperty("number")} {invoice.GetProperty("customer_name")} {invoice.GetProperty("total")} {invoice.GetProperty("currency")}");
            }
            cursor = page.RootElement.GetProperty("has_more").GetBoolean()
                ? page.RootElement.GetProperty("next_cursor").GetString()
                : null;
        } while (cursor is not null);
    }
}