import { defineConfig } from "tsup";
import { fileURLToPath } from "url";
import * as fs from "fs";
import * as path from "path";
import { csvLoader } from "inline-schema/csv-loader/esbuild";
import { yarnSpinnerPlugin } from "yarn-spinner-loader/esbuild";
import type { Plugin } from "esbuild";

const srcDir = fileURLToPath(new URL("./src", import.meta.url));
const samplesDir = fileURLToPath(new URL("./src/samples", import.meta.url));

// Auto-discover samples entry points
function getSamplesEntries(): Record<string, string> {
  const entries: Record<string, string> = {};
  if (!fs.existsSync(samplesDir)) return entries;

  for (const item of fs.readdirSync(samplesDir)) {
    const fullPath = path.join(samplesDir, item);
    if (fs.statSync(fullPath).isDirectory()) {
      // Directory sample (e.g. boop) - look for index.ts
      const indexPath = path.join(fullPath, "index.ts");
      if (fs.existsSync(indexPath)) {
        entries[item] = indexPath;
      }
    } else if (item.endsWith(".ts")) {
      // Single file sample (e.g. tic-tac-toe.ts)
      entries[item.replace(".ts", "")] = fullPath;
    }
  }
  return entries;
}

const samplesEntries = getSamplesEntries();

/**
 * Plugin to rewrite @/core/* and @/utils/* imports to use 'boardgame-core'
 */
function rewriteBoardgameImports(): Plugin {
  return {
    name: "rewrite-boardgame-imports",
    setup(build) {
      build.onResolve({ filter: /^@\/(core|utils)\// }, (args) => {
        // Mark these as external and rewrite to 'boardgame-core'
        return {
          path: "boardgame-core",
          external: true,
        };
      });

      // Also handle @/index imports
      build.onResolve({ filter: /^@\/index$/ }, (args) => {
        return {
          path: "boardgame-core",
          external: true,
        };
      });
    },
  };
}

export default defineConfig({
  entry: samplesEntries,
  format: ["esm"],
  dts: true,
  clean: true,
  sourcemap: true,
  outDir: "dist/samples",
  external: [
    "@preact/signals-core",
    "mutative",
    "inline-schema",
    "boardgame-core",
  ],
  esbuildPlugins: [
    csvLoader({ writeToDisk: true }),
    rewriteBoardgameImports(),
    yarnSpinnerPlugin(),
  ],
  esbuildOptions(options) {
    options.alias = {
      "@": srcDir,
    };
  },
});