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// 
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// Software is furnished to do so, subject to the following conditions:
// 
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using Duplicati.Library.Interface;

namespace Duplicati.Library.SecretProvider;

/// <summary>
/// Secret provider that reads secrets from environment variables
/// </summary>
public class EnvironmentSecretProvider : ISecretProvider
{
    /// <inheritdoc />
    public string Key => "env";

    /// <inheritdoc />
    public string DisplayName => Strings.EnvironmentSecretProvider.DisplayName;

    /// <inheritdoc />
    public string Description => Strings.EnvironmentSecretProvider.Description;

    /// <inheritdoc />
    public Task<bool> IsSupported(CancellationToken cancellationToken) => Task.FromResult(true);

    /// <inheritdoc />
    public bool IsSetSupported => false; // Don't set env vars as they are not persisted

    /// <inheritdoc />
    public IList<ICommandLineArgument> SupportedCommands => [];

    /// <inheritdoc />
    public Task InitializeAsync(Uri config, CancellationToken cancellationToken)
        => Task.CompletedTask;

    /// <inheritdoc />
    public Task<Dictionary<string, string>> ResolveSecretsAsync(IEnumerable<string> keys, CancellationToken cancellationToken)
    {
        var env = Environment.GetEnvironmentVariables(EnvironmentVariableTarget.Process);
        var envLookup = env.Keys.Cast<string>().ToDictionary(k => k, k => env[k] as string, StringComparer.OrdinalIgnoreCase);
        return Task.FromResult(
            keys.ToDictionary(
                k => k,
                k =>
                {
                    var value = envLookup.GetValueOrDefault(k);
                    if (string.IsNullOrWhiteSpace(value))
                        throw new UserInformationException($"The key '{k}' was not found", "KeyNotFound");
                    return value;
                }
            )
        );
    }

    /// <inheritdoc />
    public Task SetSecretAsync(string key, string value, bool overwrite, CancellationToken cancellationToken)
        => throw new NotSupportedException("Setting secrets is not supported for environment variables");
}
