using System;
using System.CommandLine;
using System.CommandLine.Invocation;
using System.Globalization;

using MfGames.Nitride.Commands;

using NodaTime;
using NodaTime.Testing;

using Serilog;

namespace MfGames.Nitride.Temporal.Cli;

/// <summary>
/// A factory to inject the "--date=XXXX-XX-XX" argument into the build
/// and other pipeline commands.
/// </summary>
public class DatePipelineCommandOption : IPipelineCommandOption
{
    private readonly ILogger logger;

    private readonly TimeService timeService;

    public DatePipelineCommandOption(
        ILogger logger,
        TimeService timeService)
    {
        this.logger = logger.ForContext<Instant>();
        this.timeService = timeService;

        this.Option = new Option<DateTime>("--date")
        {
            Description = "Sets the date to something other than now",
            ArgumentHelpName = "DATE",
        };
    }

    /// <inheritdoc />
    public Option Option { get; }

    /// <inheritdoc />
    public void Handle(InvocationContext context)
    {
        // If we got a date, then use NodaTime's fake clock to set it so
        // everything will use that.
        var value =
            (DateTime?)context.ParseResult.GetValueForOption(this.Option);

        if (value.HasValue && value.Value != DateTime.MinValue)
        {
            // We have a date, so we need to create a fake clock that has this
            // date for the entire run.
            var local = LocalDateTime.FromDateTime(value.Value);
            ZonedDateTime zoned =
                local.InZoneStrictly(this.timeService.DateTimeZone);
            var instant = zoned.ToInstant();

            this.timeService.Clock = new FakeClock(instant);
        }

        // Report the date we are processing.
        Instant now = this.timeService.Clock.GetCurrentInstant();
        ZonedDateTime dateTime = now.InZone(this.timeService.DateTimeZone);
        string formatted = dateTime.ToString("G", CultureInfo.InvariantCulture);

        this.logger.Information("Setting date/time to {When:l}", formatted);
    }
}