import { existsSync, readFileSync } from 'node:fs';
import { fileURLToPath } from 'node:url';
import { dirname, join } from 'node:path';
import { z } from 'zod';
import type { CheckCategory } from '../shared/types.js';

const categorySchema = z.array(z.string());

const repoSchema = z.object({
  name: z.string().regex(/^[\w.-]+\/[\w.-]+$/),
  checkCategories: z
    .object({
      lint: categorySchema.optional(),
      specs: categorySchema.optional(),
      e2e: categorySchema.optional(),
    })
    .default({}),
});

const configSchema = z.object({
  user: z.string(),
  onlyInvolved: z.boolean().default(true),
  pollIntervalSeconds: z.number().int().min(15).default(60),
  port: z.number().int().default(4000),
  repos: z.array(repoSchema).min(1),
});

export type RawConfig = z.infer<typeof configSchema>;

interface GlobMatcher {
  isMatch: (name: string) => boolean;
  category: CheckCategory;
}

export interface RepoRules {
  exact: Map<string, CheckCategory>;
  globs: GlobMatcher[];
}

export interface AppConfig extends RawConfig {
  rulesByRepo: Map<string, RepoRules>;
  searchQuery: string;
}

const GLOB_CHARS = /[*?]/;

/** Check names are plain strings, not paths — `*` must match anything including `/`
 *  (e.g. "Preview E2E *" → "Preview E2E e2e/regression/srm"), and `${{ }}` in names
 *  must stay literal. So we compile a minimal glob ourselves instead of picomatch. */
function compileNameGlob(pattern: string): (name: string) => boolean {
  const regex = new RegExp(
    `^${pattern.replace(/[.+^${}()|[\]\\]/g, '\\$&').replace(/\*/g, '.*').replace(/\?/g, '.')}$`,
  );
  return (name) => regex.test(name);
}

/** Project root: walk up from this module (which may live in server/ or
 *  dist-server/server/) until config.json appears. */
function findRoot(): string {
  let dir = dirname(fileURLToPath(import.meta.url));
  for (let i = 0; i < 4; i++) {
    dir = dirname(dir);
    if (existsSync(join(dir, 'config.json'))) return dir;
  }
  return process.cwd();
}

export const rootDir = findRoot();

export function loadConfig(path = join(rootDir, 'config.json')): AppConfig {
  const raw = configSchema.parse(JSON.parse(readFileSync(path, 'utf8')));

  const rulesByRepo = new Map<string, RepoRules>();
  for (const repo of raw.repos) {
    const exact = new Map<string, CheckCategory>();
    const globs: GlobMatcher[] = [];
    for (const [category, patterns] of Object.entries(repo.checkCategories) as [
      CheckCategory,
      string[],
    ][]) {
      for (const pattern of patterns ?? []) {
        if (GLOB_CHARS.test(pattern)) {
          globs.push({ isMatch: compileNameGlob(pattern), category });
        } else {
          exact.set(pattern, category);
        }
      }
    }
    rulesByRepo.set(repo.name, { exact, globs });
  }

  const parts = ['is:pr', 'is:open', ...raw.repos.map((r) => `repo:${r.name}`)];
  if (raw.onlyInvolved) parts.push(`involves:${raw.user}`);

  return { ...raw, rulesByRepo, searchQuery: parts.join(' ') };
}