// The tools' account reads every repository on the forge (the operator, 2026-10-26: "the mesh's forge account should
// get read access to all repositories").
//
// Since issue 469 the tools act as the plain account `mesh-tools`, which writes to the organisation novox's
// repositories through its team (tools-account.ts). Every other repository it saw only when public: a private
// repository of a user (jschoubben/car-hunter, jschoubben/snake) answered its tools 404 and was missing from every
// list, while that user's public ones were there. So the module makes its account a collaborator that reads only on
// each repository it cannot read, the least the forge offers: one repository, read, no organisation membership.
//
//   - **at the start**, one pass over every repository of every user and organisation;
//   - **on the forge's own event** (the system webhook, webhook.ts): `forge.repository.created` and `forge.fork` at
//     once, and the first event of any repository this process has not yet seen readable, since the forge may not
//     send a repository's creation for every owner. Nothing polls for it.
//
// **Not caught: a repository made private later.** The forge sends no event for a change of visibility, and a public
// repository is already seen readable by the start's pass, so its events ask nothing. Such a repository is granted at
// the module's next start, or now by `gitea_grant_read`; `gitea_unreadable_repos` shows it meanwhile.
//
// **The grant needs the site administrator's login.** Adding a collaborator asks the repository's administration,
// which on another user's repository only the site administrator holds; the module holds that login for setting the
// forge up (MESH_GITEA_ADMIN_PASSWORD_FILE). Here it is used through `ReadAllForge` alone: list the repositories, read
// the account's permission on one, add the account as a collaborator that reads. Nothing else, and never for the tools'
// own calls, which keep their token.
//
// What the forge refuses (a repository that went meanwhile, an archived one if the forge will not take a collaborator
// on it) is said per repository and not retried; the tool `gitea_unreadable_repos` shows what is left, and
// `gitea_grant_read` grants again now.

import type { ForgeRepository } from "./client.js";

/** What the module asks of the forge for this, with the site administrator's login (GiteaAdmin, client.ts). */
export interface ReadAllForge {
  everyRepository(): Promise<ForgeRepository[]>;
  repository(owner: string, repo: string): Promise<ForgeRepository | null>;
  repositoryPermission(owner: string, repo: string, user: string): Promise<string>;
  addReadCollaborator(owner: string, repo: string, user: string): Promise<void>;
}

/** A repository the account cannot read, and why. */
export interface Unreadable {
  repository: string;
  permission: string;
  private: boolean;
  archived: boolean;
  why: string;
}

export interface Granted {
  /** Repositories looked at. */
  checked: number;
  /** Made readable now, by a read collaborator. */
  granted: string[];
  /** The forge refused the grant: each repository and the forge's own words. */
  refused: { repository: string; why: string }[];
}

const READS = new Set(["read", "write", "admin", "owner"]);

/** Why the account cannot read a repository, from what the forge says of it. */
export function whyUnreadable(repo: ForgeRepository, account: string): string {
  const parts: string[] = [];
  if (repo.private) parts.push(`a private repository of ${repo.owner}, on which ${account} is no collaborator and in no team that covers it`);
  else if (repo.owner_visibility !== "public") {
    parts.push(`a public repository of ${repo.owner}, whose own visibility is ${repo.owner_visibility}: the forge shows it to members only`);
  } else parts.push(`the forge answers ${account} no read on it`);
  if (repo.archived) parts.push("archived");
  return parts.join("; ");
}

export class ReadAll {
  /** Repositories this process has seen the account read, by full name: an event of one of them asks nothing more. */
  readonly readable = new Set<string>();

  constructor(private readonly forge: ReadAllForge, readonly account: string,
    private readonly log: (line: string) => void = (l) => console.log(`[gitea] ${l}`)) {}

  /** Every repository the account cannot read, and why, as the forge says it now. */
  async unreadable(): Promise<{ checked: number; unreadable: Unreadable[] }> {
    const repos = await this.forge.everyRepository();
    const out: Unreadable[] = [];
    for (const repo of repos) {
      try {
        const u = await this.judge(repo);
        if (u) out.push(u);
      } catch (err) {
        // A permission the forge would not answer is said for that repository; the rest are still looked at.
        out.push({ repository: repo.full_name, permission: "unknown", private: repo.private, archived: repo.archived,
          why: `the forge did not answer ${this.account}'s permission on it — ${err instanceof Error ? err.message : String(err)}` });
      }
    }
    return { checked: repos.length, unreadable: out };
  }

  /** Grant read on every repository the account cannot read (or on those named, `owner/name`). */
  async grant(only?: string[]): Promise<Granted> {
    let repos: ForgeRepository[];
    if (only && only.length) {
      repos = [];
      for (const full of only) {
        const [owner, name, ...rest] = full.split("/");
        if (!owner || !name || rest.length) throw new Error(`"${full}" is not a repository: say owner/name`);
        const repo = await this.forge.repository(owner, name);
        if (!repo) throw new Error(`the forge holds no repository ${full}`);
        repos.push(repo);
      }
    } else repos = await this.forge.everyRepository();
    const result: Granted = { checked: repos.length, granted: [], refused: [] };
    for (const repo of repos) {
      let u: Unreadable | null;
      try {
        u = await this.judge(repo);
      } catch (err) {
        // One repository whose permission cannot be read is a refusal of its own, never the end of the pass.
        result.refused.push({ repository: repo.full_name, why: `its permission could not be read — ${err instanceof Error ? err.message : String(err)}` });
        continue;
      }
      if (!u) continue;
      try {
        await this.forge.addReadCollaborator(repo.owner, repo.name, this.account);
      } catch (err) {
        result.refused.push({ repository: repo.full_name, why: err instanceof Error ? err.message : String(err) });
        continue;
      }
      // Read back: the forge's own word that the account reads it now, never the grant's answer alone.
      let after: string;
      try {
        after = await this.forge.repositoryPermission(repo.owner, repo.name, this.account);
      } catch (err) {
        result.refused.push({ repository: repo.full_name, why: `granted, but its permission could not be read back — ${err instanceof Error ? err.message : String(err)}` });
        continue;
      }
      if (READS.has(after)) {
        this.readable.add(repo.full_name);
        result.granted.push(repo.full_name);
      } else {
        result.refused.push({ repository: repo.full_name, why: `the grant was answered, but the forge still gives ${this.account} "${after}"` });
      }
    }
    return result;
  }

  /** The start's one pass: grant what is missing and say it. Answers the result; a failure is the caller's to say. */
  async atStart(): Promise<Granted> {
    const r = await this.grant();
    this.log(`${this.account} reads every repository: ${r.checked} looked at, ${r.granted.length} granted read now` +
      `${r.granted.length ? ` (${r.granted.join(", ")})` : ""}${r.refused.length ? `, ${r.refused.length} refused: ` +
        r.refused.map((x) => `${x.repository} — ${x.why}`).join("; ") : ""}`);
    return r;
  }

  /** A forge event: a repository made (or forked), or the first event of one not seen readable, is granted read now. */
  async onEvent(event: { name: string; body: unknown }): Promise<void> {
    const b = (event.body ?? {}) as { owner?: string; repo?: string };
    if (!b.owner || !b.repo) return;
    const full = `${b.owner}/${b.repo}`;
    if (event.name === "forge.repository.deleted") {
      this.readable.delete(full);
      return;
    }
    const made = event.name === "forge.repository.created" || event.name === "forge.fork";
    // Seen readable once, its events ask nothing: so a repository made private after that is not caught here (the
    // forge says no change of visibility), only at the next start or by gitea_grant_read.
    if (!made && this.readable.has(full)) return;
    const r = await this.grant([full]);
    if (r.granted.length) this.log(`${this.account} was given read on ${full}, on the forge's ${event.name}`);
    for (const x of r.refused) this.log(`${this.account} could not be given read on ${x.repository} — ${x.why}`);
  }

  private async judge(repo: ForgeRepository): Promise<Unreadable | null> {
    const permission = await this.forge.repositoryPermission(repo.owner, repo.name, this.account);
    if (READS.has(permission)) {
      this.readable.add(repo.full_name);
      return null;
    }
    this.readable.delete(repo.full_name);
    return { repository: repo.full_name, permission, private: repo.private, archived: repo.archived, why: whyUnreadable(repo, this.account) };
  }
}

type Tool = { name: string; description: string; input: Record<string, unknown>; run: (args: Readonly<Record<string, unknown>>) => Promise<unknown> };

/** The two tools: what the account cannot read and why, and the grant now. */
export function readAllTools(readAll: () => ReadAll): Tool[] {
  return [
    {
      name: "gitea_unreadable_repos",
      description: "Every repository on the forge the tools' own account (mesh-tools) cannot read, and why: the " +
        "permission the forge gives it there, whether the repository is private or archived, and in words the reason " +
        "(a private repository of a user with the account no collaborator, an owner not public). Empty when it reads " +
        "every repository. Read with the site administrator's login, which alone sees every repository.",
      input: {},
      run: async () => readAll().unreadable(),
    },
    {
      name: "gitea_grant_read",
      description: "Give the tools' own account (mesh-tools) read on every repository it cannot read now, or on the " +
        "repositories named: each becomes a collaborator that reads only, the least the forge offers. The module does " +
        "this itself at its start and on the forge's event of a repository made; this is the same act by hand. Answers " +
        "how many were looked at, which were granted (each read back from the forge) and which the forge refused, in its " +
        "own words. Needs the site administrator's login, used for this grant alone.",
      input: {
        repositories: { type: "array", items: { type: "string" }, description: "owner/name of each repository; empty or absent, every repository" },
      },
      run: async (args) => {
        const named = Array.isArray(args.repositories) ? args.repositories.map(String) : undefined;
        return readAll().grant(named);
      },
    },
  ];
}