using InnovEnergy.App.Backend.DataTypes;

namespace InnovEnergy.App.Backend.Services;

public static class BehaviorAnalyzer
{
    private const double SolarActiveThresholdKwh = 0.1;  // min PV kWh in an hour to count as "solar active"
    private const double LowSoCThreshold         = 20.0; // % below which battery is considered depleted

    /// <summary>
    /// Derives behavioral facts from hourly data for the current week only.
    /// All computation is pure C# — no AI involved.
    /// </summary>
    public static BehavioralPattern Analyze(List<HourlyEnergyData> hourlyData)
    {
        if (hourlyData.Count == 0)
            return new BehavioralPattern();

        // ── Per-hour averages across the week ──────────────────────────────
        // Group by hour-of-day (0-23), average each metric across all days
        var byHour = Enumerable.Range(0, 24).Select(h =>
        {
            var rows = hourlyData.Where(r => r.Hour == h).ToList();
            if (rows.Count == 0)
                return (Hour: h, AvgPv: 0.0, AvgLoad: 0.0, AvgGridImport: 0.0);
            return (
                Hour:          h,
                AvgPv:         rows.Average(r => r.PvKwh),
                AvgLoad:       rows.Average(r => r.LoadKwh),
                AvgGridImport: rows.Average(r => r.GridImportKwh)
            );
        }).ToList();

        // ── Peak load hour ─────────────────────────────────────────────────
        var peakLoadEntry = byHour.OrderByDescending(h => h.AvgLoad).First();

        // ── Peak solar hour and end of solar window ────────────────────────
        var peakSolarEntry = byHour.OrderByDescending(h => h.AvgPv).First();

        // Solar window: last hour in the day where avg PV > threshold
        var solarActiveHours = byHour.Where(h => h.AvgPv >= SolarActiveThresholdKwh).ToList();
        var peakSolarEndHour = solarActiveHours.Count > 0
            ? solarActiveHours.Max(h => h.Hour)
            : peakSolarEntry.Hour;

        // ── Highest grid-import hour ────────────────────────────────────────
        var worstGridEntry = byHour.OrderByDescending(h => h.AvgGridImport).First();

        // ── Avoidable grid imports: grid drawn during hours when solar was active ──
        // For each actual hourly record: if solar > threshold AND grid import > 0 → avoidable
        var avoidableGridKwh = Math.Round(
            hourlyData
                .Where(r => r.PvKwh >= SolarActiveThresholdKwh && r.GridImportKwh > 0)
                .Sum(r => r.GridImportKwh),
            1);

        // ── Weekday vs weekend average daily load ──────────────────────────
        var weekdayDays = hourlyData
            .Where(r => !r.IsWeekend)
            .GroupBy(r => r.DateTime.Date)
            .Select(g => g.Sum(r => r.LoadKwh))
            .ToList();

        var weekendDays = hourlyData
            .Where(r => r.IsWeekend)
            .GroupBy(r => r.DateTime.Date)
            .Select(g => g.Sum(r => r.LoadKwh))
            .ToList();

        var weekdayAvg = weekdayDays.Count > 0 ? Math.Round(weekdayDays.Average(), 1) : 0;
        var weekendAvg = weekendDays.Count > 0 ? Math.Round(weekendDays.Average(), 1) : 0;

        // ── Battery depletion hour ─────────────────────────────────────────
        // For each day, find the first evening hour (after 18:00) where SoC < threshold
        // Average that hour across days where it occurs
        var depletionHours = hourlyData
            .Where(r => r.Hour >= 18 && r.BattSoC > 0 && r.BattSoC < LowSoCThreshold)
            .GroupBy(r => r.DateTime.Date)
            .Select(g => g.OrderBy(r => r.Hour).First().Hour)
            .ToList();

        var avgDepletedHour     = depletionHours.Count > 0 ? (int)Math.Round(depletionHours.Average()) : -1;
        var batteryDepletsNight = depletionHours.Count >= 3; // happens on 3+ nights = consistent pattern

        return new BehavioralPattern
        {
            PeakLoadHour             = peakLoadEntry.Hour,
            AvgPeakLoadKwh           = Math.Round(peakLoadEntry.AvgLoad, 2),
            PeakSolarHour            = peakSolarEntry.Hour,
            PeakSolarEndHour         = peakSolarEndHour,
            AvgPeakSolarKwh          = Math.Round(peakSolarEntry.AvgPv, 2),
            HighestGridImportHour    = worstGridEntry.Hour,
            AvgGridImportAtPeakHour  = Math.Round(worstGridEntry.AvgGridImport, 2),
            AvoidableGridKwh         = avoidableGridKwh,
            WeekdayAvgDailyLoad      = weekdayAvg,
            WeekendAvgDailyLoad      = weekendAvg,
            AvgBatteryDepletedHour   = avgDepletedHour,
            BatteryDepletesOvernight = batteryDepletsNight,
        };
    }
}