// The mesh's own forge accounts read every repository on the forge (the operator, 2026-10-26: "the mesh's forge account
// should get read access to all repositories"; and "why wouldn't the forge account get access to all repo's?").
//
// **Every account the mesh's parts use, from one list** (MESH_ACCOUNTS, tools-account.ts): the tools' `mesh-tools`, the
// build modules' `nox-builder` (their fetch over ssh, ADR 0466 §3) and the machines' `nox-agent` (ssh-client's key,
// ADR 0410 §1). The first pass granted the tools' account alone, so the build modules' fetch of jschoubben/car-hunter
// still failed on ace and g14 ("nox-builder ... is not authorized to read"). The two Go names are the ones of
// internal/forgeaccount, whose test holds the list to them. An account the forge does not hold yet (its consumer never
// asked) is said and left out, never a refusal per repository.
//
// 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>;
  /** Whether the forge holds the account at all. */
  accountExists(user: string): Promise<boolean>;
  repositoryPermission(owner: string, repo: string, user: string): Promise<string>;
  addReadCollaborator(owner: string, repo: string, user: string): Promise<void>;
}

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

export interface Granted {
  /** Repositories looked at (for each account). */
  checked: number;
  /** The accounts looked at: those the forge holds. */
  accounts: string[];
  /** Accounts of the list the forge does not hold yet: nothing is granted to them until it does. */
  absent: string[];
  /** Made readable now, by a read collaborator: each repository and the account. */
  granted: { account: string; repository: string }[];
  /** The forge refused the grant: each repository, the account and the forge's own words. */
  refused: { account: string; repository: string; why: string }[];
}

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

const said = (err: unknown): string => (err instanceof Error ? err.message : String(err));

/** 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 {
  /** Per account, the repositories this process has seen it read, by full name: an event of a repository every account
   *  was seen reading asks nothing more. */
  readonly readable = new Map<string, Set<string>>();
  readonly accounts: readonly string[];

  constructor(private readonly forge: ReadAllForge, accounts: readonly string[] | string,
    private readonly log: (line: string) => void = (l) => console.log(`[gitea] ${l}`)) {
    this.accounts = [...new Set(typeof accounts === "string" ? [accounts] : accounts)];
    if (!this.accounts.length) throw new Error("no forge account to give read: the list is empty");
    for (const a of this.accounts) this.readable.set(a, new Set());
  }

  /** The accounts of the list (or of those named) the forge holds, and those it does not hold yet. */
  private async present(only?: string[]): Promise<{ accounts: string[]; absent: string[] }> {
    const wanted = only && only.length ? only : [...this.accounts];
    for (const a of wanted) if (!this.accounts.includes(a)) throw new Error(`"${a}" is not one of the mesh's accounts: ${this.accounts.join(", ")}`);
    const accounts: string[] = [];
    const absent: string[] = [];
    for (const a of wanted) ((await this.forge.accountExists(a)) ? accounts : absent).push(a);
    return { accounts, absent };
  }

  /** Every repository each account cannot read, and why, as the forge says it now. */
  async unreadable(only?: string[]): Promise<{ checked: number; accounts: { account: string; unreadable: number }[]; absent: string[]; unreadable: Unreadable[] }> {
    const { accounts, absent } = await this.present(only);
    const repos = await this.forge.everyRepository();
    const out: Unreadable[] = [];
    for (const account of accounts) {
      for (const repo of repos) {
        try {
          const u = await this.judge(repo, account);
          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({ account, repository: repo.full_name, permission: "unknown", private: repo.private, archived: repo.archived,
            why: `the forge did not answer ${account}'s permission on it — ${said(err)}` });
        }
      }
    }
    return { checked: repos.length, accounts: accounts.map((account) => ({ account, unreadable: out.filter((u) => u.account === account).length })),
      absent, unreadable: out };
  }

  /** Grant read on every repository an account cannot read (or on those named, `owner/name`), for every account of the
   *  list the forge holds (or for those named). */
  async grant(only?: string[], accountsOnly?: string[]): Promise<Granted> {
    const { accounts, absent } = await this.present(accountsOnly);
    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, accounts, absent, granted: [], refused: [] };
    for (const account of accounts) {
      for (const repo of repos) {
        const repository = repo.full_name;
        let u: Unreadable | null;
        try {
          u = await this.judge(repo, account);
        } catch (err) {
          // One repository whose permission cannot be read is a refusal of its own, never the end of the pass.
          result.refused.push({ account, repository, why: `its permission could not be read — ${said(err)}` });
          continue;
        }
        if (!u) continue;
        try {
          await this.forge.addReadCollaborator(repo.owner, repo.name, account);
        } catch (err) {
          result.refused.push({ account, repository, why: said(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, account);
        } catch (err) {
          result.refused.push({ account, repository, why: `granted, but its permission could not be read back — ${said(err)}` });
          continue;
        }
        if (READS.has(after)) {
          this.readable.get(account)!.add(repository);
          result.granted.push({ account, repository });
        } else {
          result.refused.push({ account, repository, why: `the grant was answered, but the forge still gives ${account} "${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();
    const per = r.accounts.map((a) => {
      const g = r.granted.filter((x) => x.account === a).map((x) => x.repository);
      return `${a} ${g.length} granted read now${g.length ? ` (${g.join(", ")})` : ""}`;
    });
    this.log(`the mesh's accounts read every repository: ${r.checked} looked at; ${per.join("; ")}` +
      `${r.absent.length ? `; not on the forge yet, so not granted: ${r.absent.join(", ")}` : ""}` +
      `${r.refused.length ? `; ${r.refused.length} refused: ` + r.refused.map((x) => `${x.account} on ${x.repository} — ${x.why}`).join("; ") : ""}`);
    return r;
  }

  /** A forge event: a repository made (or forked), or the first event of one some account was not seen reading, is
   *  granted read now to every account that cannot read it. */
  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") {
      for (const seen of this.readable.values()) seen.delete(full);
      return;
    }
    const made = event.name === "forge.repository.created" || event.name === "forge.fork";
    // Seen readable once by every account, 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.values()].every((seen) => seen.has(full))) return;
    const r = await this.grant([full]);
    for (const x of r.granted) this.log(`${x.account} was given read on ${full}, on the forge's ${event.name}`);
    for (const x of r.refused) this.log(`${x.account} could not be given read on ${x.repository} — ${x.why}`);
  }

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

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

const strings = (v: unknown): string[] | undefined => (Array.isArray(v) ? v.map(String) : undefined);

/** The two tools: what each 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 one of the mesh's own forge accounts cannot read, and why, per account: " +
        "the tools' (mesh-tools), the build modules' fetch over ssh (nox-builder) and the machines' agents' (nox-agent). " +
        "For each, 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); a count per " +
        "account, and the accounts the forge does not hold yet. Empty when every account reads every repository. Read " +
        "with the site administrator's login, which alone sees every repository.",
      input: {
        accounts: { type: "array", items: { type: "string" }, description: "the accounts to look at; empty or absent, every one of the mesh's" },
      },
      run: async (args) => readAll().unreadable(strings(args.accounts)),
    },
    {
      name: "gitea_grant_read",
      description: "Give each of the mesh's own forge accounts (mesh-tools, nox-builder, nox-agent) read on every " +
        "repository it cannot read now, or on the repositories named, or for the accounts 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, such as when a build's fetch says its account " +
        "is not authorized to read a repository. Answers how many were looked at, which were granted to which account " +
        "(each read back from the forge), which the forge refused, in its own words, and the accounts it does not hold " +
        "yet. 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" },
        accounts: { type: "array", items: { type: "string" }, description: "the accounts to grant; empty or absent, every one of the mesh's" },
      },
      run: async (args) => readAll().grant(strings(args.repositories), strings(args.accounts)),
    },
  ];
}