/**
 * earth-now.co
 * Author:  Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 * File:    packages/widget/test/widget.test.ts
 * Purpose: Unit tests for the widget's pure helpers — config resolution, payload parsing, display text
 */

import { describe, expect, it } from "vitest";
import type { CounterModel } from "@earth-now/counter";
import {
  DEFAULT_API,
  buildDisplayText,
  modelUrl,
  parseModelPayload,
  resolveConfig,
} from "../src/render";

const ANCHOR = "2026-01-01T00:00:00Z";
const ANCHOR_MS = Date.parse(ANCHOR);

const linearModel: CounterModel = {
  metricId: "co2_emissions_ytd",
  anchorValue: 1_000_000,
  anchorTime: ANCHOR,
  rateFn: { kind: "linear", perSecond: 2 },
  observedAt: "2025-12-15T00:00:00Z",
  sourceId: "gcp_2025",
  modelVersion: "linear-v1",
  displayHints: { decimals: 0, sigFigs: 4, unit: "t" },
};

describe("resolveConfig", () => {
  it("resolves a full dataset", () => {
    const config = resolveConfig({
      earthNowMetric: "co2_emissions_ytd",
      window: "today",
      lang: "fr",
      api: "https://www.earth-now.co/",
    });
    expect(config).toEqual({
      metricId: "co2_emissions_ytd",
      window: "today",
      lang: "fr",
      api: "https://www.earth-now.co",
    });
  });

  it("applies defaults (window total, lang en, official api)", () => {
    const config = resolveConfig({ earthNowMetric: "world_population" });
    expect(config).toEqual({
      metricId: "world_population",
      window: "total",
      lang: "en",
      api: DEFAULT_API,
    });
  });

  it("falls back to 'total' on an unknown window", () => {
    expect(resolveConfig({ earthNowMetric: "x", window: "weird" })?.window).toBe("total");
  });

  it("returns null when no metric id is declared", () => {
    expect(resolveConfig({})).toBeNull();
    expect(resolveConfig({ earthNowMetric: "  " })).toBeNull();
  });
});

describe("modelUrl", () => {
  it("builds the /v1 model endpoint and escapes the metric id", () => {
    const config = resolveConfig({ earthNowMetric: "a/b", api: "https://example.org" });
    expect(config && modelUrl(config)).toBe("https://example.org/v1/metrics/a%2Fb/model");
  });
});

describe("parseModelPayload", () => {
  it("accepts a bare model and an { model } envelope", () => {
    expect(parseModelPayload(linearModel).metricId).toBe("co2_emissions_ytd");
    expect(parseModelPayload({ model: linearModel }).anchorValue).toBe(1_000_000);
  });

  it("throws descriptive errors on malformed payloads", () => {
    expect(() => parseModelPayload(null)).toThrow(/not an object/);
    expect(() => parseModelPayload({})).toThrow(/metricId/);
    expect(() => parseModelPayload({ ...linearModel, anchorValue: "nope" })).toThrow(
      /anchorValue/,
    );
    expect(() => parseModelPayload({ ...linearModel, anchorTime: "not-a-date" })).toThrow(
      /anchorTime/,
    );
    expect(() => parseModelPayload({ ...linearModel, rateFn: 42 })).toThrow(/rateFn/);
  });
});

describe("buildDisplayText", () => {
  const config = {
    metricId: "co2_emissions_ytd",
    window: "total" as const,
    lang: "en",
    api: DEFAULT_API,
  };

  it("renders the animated value WITHOUT the sigFigs cap (ticker mode)", () => {
    // 100 s after anchor: 1_000_000 + 2 * 100 = 1_000_200; sigFigs 4 would flatten to 1_000_000.
    const text = buildDisplayText(linearModel, ANCHOR_MS + 100_000, config);
    expect(text.value).toBe("1,000,200");
    expect(text.unit).toBe("t");
  });

  it("renders the per-second rate line", () => {
    const text = buildDisplayText(linearModel, ANCHOR_MS + 100_000, config);
    expect(text.rate).toBe("2/s");
  });

  it("resolves the 'today' window from the same model", () => {
    // 2026-01-02T00:00:30Z → 30 s into the UTC day at 2/s = 60.
    const t = Date.parse("2026-01-02T00:00:30Z");
    const text = buildDisplayText(linearModel, t, { ...config, window: "today" });
    expect(text.value).toBe("60");
  });

  it("uses the caller-provided session start for 'session' windows", () => {
    const sessionStart = ANCHOR_MS + 10_000;
    const text = buildDisplayText(
      linearModel,
      sessionStart + 45_000,
      { ...config, window: "session" },
      sessionStart,
    );
    expect(text.value).toBe("90");
  });

  it("formats according to the requested locale", () => {
    const text = buildDisplayText(linearModel, ANCHOR_MS + 100_000, { ...config, lang: "fr" });
    // fr uses narrow no-break spaces as grouping separators.
    expect(text.value.replace(/[  ]/g, " ")).toBe("1 000 200");
  });
});