// ABOUTME: API route for today's training decision and data.
// ABOUTME: Returns complete daily snapshot with decision, biometrics, and nutrition.
import { NextResponse } from "next/server";

import { withAuth } from "@/lib/auth-middleware";
import {
  getCycleDay,
  getPhase,
  getPhaseConfig,
  getPhaseLimit,
} from "@/lib/cycle";
import { getDecisionWithOverrides } from "@/lib/decision-engine";
import { logger } from "@/lib/logger";
import { getNutritionGuidance, getSeedSwitchAlert } from "@/lib/nutrition";
import type { DailyData, DailyLog, HrvStatus } from "@/types";

// Default biometrics when no Garmin data is available
const DEFAULT_BIOMETRICS: {
  hrvStatus: HrvStatus;
  bodyBatteryCurrent: number;
  bodyBatteryYesterdayLow: number;
  weekIntensityMinutes: number;
} = {
  hrvStatus: "Unknown",
  bodyBatteryCurrent: 100,
  bodyBatteryYesterdayLow: 100,
  weekIntensityMinutes: 0,
};

export const GET = withAuth(async (_request, user, pb) => {
  // Fetch fresh user data from database to get latest values
  // The user param from withAuth is from auth store cache which may be stale
  // (e.g., after logging a period, the cookie still has old data)
  const freshUser = await pb.collection("users").getOne(user.id);

  // Validate required user data
  if (!freshUser.lastPeriodDate) {
    return NextResponse.json(
      {
        error:
          "User has no lastPeriodDate set. Please log your period start date first.",
      },
      { status: 400 },
    );
  }
  const lastPeriodDate = new Date(freshUser.lastPeriodDate as string);
  const cycleLength = freshUser.cycleLength as number;
  const activeOverrides = (freshUser.activeOverrides as string[]) || [];

  // Calculate cycle information
  const cycleDay = getCycleDay(lastPeriodDate, cycleLength, new Date());
  const phase = getPhase(cycleDay, cycleLength);
  const phaseConfig = getPhaseConfig(phase);
  const phaseLimit = getPhaseLimit(phase);

  // Calculate days until next phase using dynamic boundaries
  // Phase boundaries: MENSTRUAL 1-3, FOLLICULAR 4-(cl-16), OVULATION (cl-15)-(cl-14),
  // EARLY_LUTEAL (cl-13)-(cl-7), LATE_LUTEAL (cl-6)-cl
  let daysUntilNextPhase: number;
  if (phase === "LATE_LUTEAL") {
    daysUntilNextPhase = cycleLength - cycleDay + 1;
  } else if (phase === "MENSTRUAL") {
    daysUntilNextPhase = 4 - cycleDay;
  } else if (phase === "FOLLICULAR") {
    daysUntilNextPhase = cycleLength - 15 - cycleDay;
  } else if (phase === "OVULATION") {
    daysUntilNextPhase = cycleLength - 13 - cycleDay;
  } else {
    // EARLY_LUTEAL
    daysUntilNextPhase = cycleLength - 6 - cycleDay;
  }

  // Try to fetch today's DailyLog for biometrics
  // Sort by date DESC to get the most recent record if multiple exist
  let biometrics = { ...DEFAULT_BIOMETRICS, phaseLimit };
  try {
    // Use YYYY-MM-DD format with >= and < operators for PocketBase date field
    // PocketBase accepts simple date strings in comparison operators
    const today = new Date().toISOString().split("T")[0];
    const tomorrow = new Date(Date.now() + 86400000)
      .toISOString()
      .split("T")[0];

    logger.info({ userId: user.id, today, tomorrow }, "Fetching dailyLog");
    const dailyLog = await pb
      .collection("dailyLogs")
      .getFirstListItem<DailyLog>(
        `user="${user.id}" && date>="${today}" && date<"${tomorrow}"`,
        { sort: "-date" },
      );

    logger.info(
      {
        userId: user.id,
        dailyLogId: dailyLog.id,
        hrvStatus: dailyLog.hrvStatus,
        bodyBatteryCurrent: dailyLog.bodyBatteryCurrent,
      },
      "Found dailyLog",
    );

    biometrics = {
      hrvStatus: dailyLog.hrvStatus,
      bodyBatteryCurrent:
        dailyLog.bodyBatteryCurrent ?? DEFAULT_BIOMETRICS.bodyBatteryCurrent,
      bodyBatteryYesterdayLow:
        dailyLog.bodyBatteryYesterdayLow ??
        DEFAULT_BIOMETRICS.bodyBatteryYesterdayLow,
      weekIntensityMinutes: dailyLog.weekIntensityMinutes,
      phaseLimit: dailyLog.phaseLimit,
    };
  } catch (err) {
    logger.warn({ userId: user.id, err }, "No dailyLog found, using defaults");
  }

  // Build DailyData for decision engine
  const dailyData: DailyData = {
    hrvStatus: biometrics.hrvStatus,
    bbYesterdayLow: biometrics.bodyBatteryYesterdayLow,
    phase,
    weekIntensity: biometrics.weekIntensityMinutes,
    phaseLimit: biometrics.phaseLimit,
    bbCurrent: biometrics.bodyBatteryCurrent,
  };

  // Get training decision with override handling
  const decision = getDecisionWithOverrides(
    dailyData,
    activeOverrides as import("@/types").OverrideType[],
  );

  // Log decision calculation per observability spec
  logger.info(
    { userId: user.id, decision: decision.status, reason: decision.reason },
    "Decision calculated",
  );

  // Get nutrition guidance with seed switch alert
  const baseNutrition = getNutritionGuidance(cycleDay);
  const nutrition = {
    ...baseNutrition,
    seedSwitchAlert: getSeedSwitchAlert(cycleDay),
  };

  return NextResponse.json({
    decision,
    cycleDay,
    phase,
    phaseConfig,
    daysUntilNextPhase,
    cycleLength,
    biometrics,
    nutrition,
  });
});