import assert from "node:assert/strict";
import test from "node:test";

import type { DiagramIRV2 } from "../../model/diagram-ir.js";
import { applyMetricsHeatmap } from "./heatmap.js";
import { contrastRatio } from "../themes/theme-service.js";

const IR: DiagramIRV2 = {
  version: 2,
  pages: [{ id: "p", title: "Page", nodes: [
    { id: "low", label: "Low", style: "shape=hexagon;strokeColor=#000000;", geometry: { x: 0, y: 0, width: 100, height: 60 } },
    { id: "high", label: "High", style: "shape=ellipse;", geometry: { x: 200, y: 0, width: 100, height: 60 } },
  ], edges: [{ id: "flow", source: "low", target: "high", waypoints: [{ x: 150, y: 30 }] }] }],
};

test("metrics heatmap is deterministic with legend metadata and preserves topology", () => {
  const request = { metric: "latency_ms", min: 0, max: 100, values: { "p/low": 0, "p/high": 100 } };
  const snapshot = structuredClone(IR);
  const first = applyMetricsHeatmap(IR, request);
  assert.deepEqual(first, applyMetricsHeatmap(IR, request));
  assert.deepEqual(IR, snapshot);
  assert.deepEqual(first.legend, {
    metric: "latency_ms", min: 0, max: 100,
    stops: [
      { value: 0, color: "#440154", fontColor: "#FFFFFF" },
      { value: 25, color: "#3B528B", fontColor: "#FFFFFF" },
      { value: 50, color: "#21918C", fontColor: "#1A1A1A" },
      { value: 75, color: "#5EC962", fontColor: "#1A1A1A" },
      { value: 100, color: "#FDE725", fontColor: "#1A1A1A" },
    ],
  });
  assert.match(first.diagram.pages[0].nodes[0].style!, /shape=hexagon/);
  assert.match(first.diagram.pages[0].nodes[0].style!, /fillColor=#440154/);
  assert.match(first.diagram.pages[0].nodes[1].style!, /fillColor=#FDE725/);
  assert.deepEqual(first.diagram.pages[0].edges, IR.pages[0].edges);
  assert.deepEqual(first.diagram.pages[0].nodes.map(({ id, geometry }) => ({ id, geometry })), IR.pages[0].nodes.map(({ id, geometry }) => ({ id, geometry })));
});

test("metrics heatmap sets readable text for every palette stop", () => {
  const result = applyMetricsHeatmap(IR, {
    metric: "latency_ms", min: 0, max: 100,
    values: { "p/low": 0, "p/high": 100 },
  });

  for (const stop of result.legend.stops) {
    assert.ok(contrastRatio(stop.fontColor, stop.color) >= 4.5, `${stop.fontColor} on ${stop.color}`);
  }
  assert.match(result.diagram.pages[0].nodes[0].style!, /fontColor=#FFFFFF/);
  assert.match(result.diagram.pages[0].nodes[1].style!, /fontColor=#1A1A1A/);
});

test("metrics heatmap switches colors at the legend stop boundaries", () => {
  const colorsAt = (low: number, high: number): string[] => applyMetricsHeatmap(IR, {
    metric: "latency_ms", min: 0, max: 100, values: { "p/low": low, "p/high": high },
  }).diagram.pages[0].nodes.map((node) => /fillColor=(#[0-9A-F]{6})/i.exec(node.style!)?.[1] ?? "");

  assert.deepEqual(colorsAt(24.999, 25), ["#440154", "#3B528B"]);
  assert.deepEqual(colorsAt(49.999, 50), ["#3B528B", "#21918C"]);
  assert.deepEqual(colorsAt(74.999, 75), ["#21918C", "#5EC962"]);
  assert.deepEqual(colorsAt(99.999, 100), ["#5EC962", "#FDE725"]);
});

test("metrics heatmap rejects palettes without a readable text color", () => {
  assert.throws(() => applyMetricsHeatmap(IR, {
    metric: "x", min: 0, max: 1, values: {}, colors: ["#777777", "#777777"],
  }), /no readable font color/i);
});

test("metrics heatmap rejects invalid bounds, colors, keys, and out-of-range values", () => {
  assert.throws(() => applyMetricsHeatmap(IR, { metric: "x", min: 1, max: 1, values: {} }), /min.*max/i);
  assert.throws(() => applyMetricsHeatmap(IR, { metric: "x", min: 0, max: 1, values: { "p/low": 2 } }), /bounded/i);
  assert.throws(() => applyMetricsHeatmap(IR, { metric: "x", min: 0, max: 1, values: { missing: 0 } }), /unknown/i);
  assert.throws(() => applyMetricsHeatmap(IR, { metric: "x", min: 0, max: 1, values: {}, colors: ["red"] }), /color/i);
});