// ABOUTME: Unit tests for the training decision engine.
// ABOUTME: Tests all 8 priority rules and 4 override scenarios.
import { describe, expect, it } from "vitest";

import type { DailyData, OverrideType } from "@/types";
import {
  getDecisionWithOverrides,
  getTrainingDecision,
} from "./decision-engine";

// Helper to create baseline "healthy" data where TRAIN would be the decision
function createHealthyData(): DailyData {
  return {
    hrvStatus: "Balanced",
    bbYesterdayLow: 50, // above 30
    phase: "FOLLICULAR", // not LATE_LUTEAL or MENSTRUAL
    weekIntensity: 0, // well below limit
    phaseLimit: 120,
    bbCurrent: 90, // above 85
  };
}

describe("getTrainingDecision (algorithmic rules)", () => {
  describe("Priority 1: HRV Unbalanced", () => {
    it("forces REST when HRV is Unbalanced", () => {
      const data = createHealthyData();
      data.hrvStatus = "Unbalanced";
      const result = getTrainingDecision(data);
      expect(result.status).toBe("REST");
      expect(result.reason).toContain("HRV");
    });
  });

  describe("Priority 2: Body Battery Yesterday Low", () => {
    it("forces REST when BB yesterday low is below 30", () => {
      const data = createHealthyData();
      data.bbYesterdayLow = 25;
      const result = getTrainingDecision(data);
      expect(result.status).toBe("REST");
      expect(result.reason).toContain("BB");
    });
  });

  describe("Priority 3: Late Luteal Phase", () => {
    it("forces GENTLE during late luteal phase", () => {
      const data = createHealthyData();
      data.phase = "LATE_LUTEAL";
      const result = getTrainingDecision(data);
      expect(result.status).toBe("GENTLE");
      expect(result.reason).toContain("rebounding");
    });
  });

  describe("Priority 4: Menstrual Phase", () => {
    it("forces GENTLE during menstrual phase", () => {
      const data = createHealthyData();
      data.phase = "MENSTRUAL";
      const result = getTrainingDecision(data);
      expect(result.status).toBe("GENTLE");
      expect(result.reason).toContain("rebounding");
    });
  });

  describe("Priority 5: Weekly Intensity Limit", () => {
    it("forces REST when weekly intensity meets limit", () => {
      const data = createHealthyData();
      data.weekIntensity = 120; // equals phaseLimit
      const result = getTrainingDecision(data);
      expect(result.status).toBe("REST");
      expect(result.reason).toContain("LIMIT");
    });

    it("forces REST when weekly intensity exceeds limit", () => {
      const data = createHealthyData();
      data.weekIntensity = 150; // exceeds phaseLimit
      const result = getTrainingDecision(data);
      expect(result.status).toBe("REST");
    });
  });

  describe("Priority 6: Body Battery Current Low", () => {
    it("forces LIGHT when current BB is below 75", () => {
      const data = createHealthyData();
      data.bbCurrent = 70;
      const result = getTrainingDecision(data);
      expect(result.status).toBe("LIGHT");
      expect(result.reason).toContain("BB");
    });
  });

  describe("Priority 7: Body Battery Current Medium", () => {
    it("forces REDUCED when current BB is below 85 but above 74", () => {
      const data = createHealthyData();
      data.bbCurrent = 80;
      const result = getTrainingDecision(data);
      expect(result.status).toBe("REDUCED");
      expect(result.reason).toContain("25%");
    });
  });

  describe("Priority 8: Default", () => {
    it("returns TRAIN when all conditions are favorable", () => {
      const data = createHealthyData();
      const result = getTrainingDecision(data);
      expect(result.status).toBe("TRAIN");
      expect(result.reason).toContain("OK to train");
    });
  });

  describe("Priority enforcement", () => {
    it("HRV Unbalanced takes precedence over low BB yesterday", () => {
      const data = createHealthyData();
      data.hrvStatus = "Unbalanced";
      data.bbYesterdayLow = 25;
      const result = getTrainingDecision(data);
      expect(result.reason).toContain("HRV");
    });

    it("low BB yesterday takes precedence over phase-based rules", () => {
      const data = createHealthyData();
      data.bbYesterdayLow = 25;
      data.phase = "LATE_LUTEAL";
      const result = getTrainingDecision(data);
      expect(result.status).toBe("REST");
      expect(result.reason).toContain("BB");
    });
  });
});

describe("getDecisionWithOverrides", () => {
  describe("override types force REST", () => {
    it("flare override forces REST", () => {
      const data = createHealthyData();
      const overrides: OverrideType[] = ["flare"];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.status).toBe("REST");
      expect(result.reason).toContain("flare");
    });

    it("stress override forces REST", () => {
      const data = createHealthyData();
      const overrides: OverrideType[] = ["stress"];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.status).toBe("REST");
      expect(result.reason).toContain("stress");
    });

    it("sleep override forces REST", () => {
      const data = createHealthyData();
      const overrides: OverrideType[] = ["sleep"];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.status).toBe("REST");
      expect(result.reason).toContain("sleep");
    });

    it("pms override forces REST", () => {
      const data = createHealthyData();
      const overrides: OverrideType[] = ["pms"];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.status).toBe("REST");
      expect(result.reason).toContain("pms");
    });
  });

  describe("override priority (flare > stress > sleep > pms)", () => {
    it("flare takes precedence over stress", () => {
      const data = createHealthyData();
      const overrides: OverrideType[] = ["stress", "flare"];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.reason).toContain("flare");
      expect(result.reason).not.toContain("stress");
    });

    it("stress takes precedence over sleep", () => {
      const data = createHealthyData();
      const overrides: OverrideType[] = ["sleep", "stress"];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.reason).toContain("stress");
      expect(result.reason).not.toContain("sleep");
    });

    it("sleep takes precedence over pms", () => {
      const data = createHealthyData();
      const overrides: OverrideType[] = ["pms", "sleep"];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.reason).toContain("sleep");
      expect(result.reason).not.toContain("pms");
    });

    it("respects full priority chain with all overrides", () => {
      const data = createHealthyData();
      const overrides: OverrideType[] = ["pms", "sleep", "stress", "flare"];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.reason).toContain("flare");
    });
  });

  describe("overrides bypass algorithmic rules", () => {
    it("flare override bypasses favorable conditions", () => {
      const data = createHealthyData();
      // Normally this would return TRAIN
      const overrides: OverrideType[] = ["flare"];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.status).toBe("REST");
    });

    it("stress override works even with perfect biometrics", () => {
      const data = createHealthyData();
      data.bbCurrent = 100;
      data.bbYesterdayLow = 80;
      const overrides: OverrideType[] = ["stress"];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.status).toBe("REST");
    });
  });

  describe("empty overrides fall through to algorithmic rules", () => {
    it("returns TRAIN with no overrides and healthy data", () => {
      const data = createHealthyData();
      const overrides: OverrideType[] = [];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.status).toBe("TRAIN");
    });

    it("returns REST for HRV Unbalanced with no overrides", () => {
      const data = createHealthyData();
      data.hrvStatus = "Unbalanced";
      const overrides: OverrideType[] = [];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.status).toBe("REST");
      expect(result.reason).toContain("HRV");
    });

    it("algorithmic rules apply when overrides array is empty", () => {
      const data = createHealthyData();
      data.bbCurrent = 70;
      const overrides: OverrideType[] = [];
      const result = getDecisionWithOverrides(data, overrides);
      expect(result.status).toBe("LIGHT");
    });
  });
});