/**
 * Route handlers for the brain graph visualization endpoint.
 *
 * Queries the memory database to return a knowledge graph shaped for brain-lobe
 * visualization, with memory items mapped to brain regions based on their type.
 */

import { readFileSync } from "node:fs";
import { join } from "node:path";

import { count } from "drizzle-orm";
import { z } from "zod";

import { getMemoryDb } from "../../persistence/db-connection.js";
import { memoryGraphNodes } from "../../persistence/schema/index.js";
import { resolveBundledDir } from "../../util/bundled-asset.js";
import { ACTOR_PRINCIPALS } from "../auth/route-policy.js";
import { RouteError } from "./errors.js";
import type { RouteDefinition } from "./types.js";

function getMemoryKindColor(kind: string): string {
  switch (kind) {
    case "episodic":
      return "#ec4899"; // pink — specific moments/events
    case "semantic":
      return "#3b82f6"; // blue — facts/knowledge
    case "procedural":
      return "#10b981"; // green — skills/how-to
    case "emotional":
      return "#ef4444"; // red — feelings
    case "prospective":
      return "#f59e0b"; // amber — future-oriented
    case "behavioral":
      return "#8b5cf6"; // violet — behavioral patterns
    case "narrative":
      return "#6366f1"; // indigo — stories
    case "shared":
      return "#14b8a6"; // teal — relationship memories
    default:
      return "#94a3b8";
  }
}

function handleGetBrainGraph() {
  const db = getMemoryDb();
  const kindCountRows =
    db
      ?.select({
        kind: memoryGraphNodes.type,
        count: count(),
      })
      .from(memoryGraphNodes)
      .groupBy(memoryGraphNodes.type)
      .all() ?? [];

  const memorySummary = kindCountRows.map((row) => ({
    kind: row.kind,
    count: row.count,
    color: getMemoryKindColor(row.kind),
  }));

  const totalKnowledgeCount = memorySummary.reduce(
    (sum, entry) => sum + entry.count,
    0,
  );

  return {
    entities: [],
    relations: [],
    memorySummary,
    totalKnowledgeCount,
    generatedAt: new Date().toISOString(),
  };
}

const BRAIN_GRAPH_CSP = [
  "default-src 'self'",
  "script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.jsdelivr.net https://d3js.org",
  "style-src 'self' 'unsafe-inline' https://fonts.googleapis.com",
  "font-src 'self' https://fonts.gstatic.com",
  "connect-src 'self'",
  "img-src 'self' data:",
].join("; ");

function handleServeBrainGraphUI(): string {
  const brainGraphDir = resolveBundledDir(
    import.meta.dirname ?? __dirname,
    "./brain-graph",
    "brain-graph",
  );
  const htmlPath = join(brainGraphDir, "brain-graph.html");

  try {
    return readFileSync(htmlPath, "utf-8");
  } catch {
    throw new RouteError("Brain graph UI not available", "INTERNAL_ERROR", 500);
  }
}

// ---------------------------------------------------------------------------
// Route definitions
// ---------------------------------------------------------------------------

export const ROUTES: RouteDefinition[] = [
  {
    operationId: "brain_graph_get",
    endpoint: "brain-graph",
    method: "GET",
    policy: {
      requiredScopes: ["settings.read"],
      allowedPrincipalTypes: ACTOR_PRINCIPALS,
    },
    summary: "Get brain graph data",
    description:
      "Return a knowledge-graph shaped for brain-lobe visualization, with memory items mapped to brain regions.",
    tags: ["brain-graph"],
    responseBody: z.object({
      entities: z.array(z.unknown()).describe("Graph entity nodes"),
      relations: z.array(z.unknown()).describe("Graph relation edges"),
      memorySummary: z
        .array(z.unknown())
        .describe("Memory kind counts and colors"),
      totalKnowledgeCount: z.number().int(),
      generatedAt: z.string().describe("ISO 8601 timestamp"),
    }),
    handler: () => handleGetBrainGraph(),
  },
  {
    operationId: "brain_graph_ui",
    endpoint: "brain-graph-ui",
    method: "GET",
    policy: {
      requiredScopes: ["settings.read"],
      allowedPrincipalTypes: ACTOR_PRINCIPALS,
    },
    summary: "Serve brain graph UI",
    description:
      "Return the brain-graph HTML visualization page. The gateway injects an auth token before serving.",
    tags: ["brain-graph"],
    responseHeaders: {
      "Content-Type": "text/html; charset=utf-8",
      "Content-Security-Policy": BRAIN_GRAPH_CSP,
    },
    handler: () => handleServeBrainGraphUI(),
  },
];