# Per-agent matrix integration: the `services.hyperhive.agent.matrix.*` +
# `services.hyperhive.agent.matrixAccounts` options, the long-running
# hive-matrix-daemon (serves its MCP tools directly over
# streamable-http), its token-arrival path trigger, and the
# auto-injected extraMcpServers entry.
#
# There is no `matrix.enable`. An agent has matrix exactly when it has an
# account to serve — see `matrixEnabled` below.
{
  pkgs,
  lib,
  config,
  ...
}:
let
  userName = config.services.hyperhive.agent.user.name;
  # This agent's own state dir, where hive-c0re provisions the
  # hive-internal account's token (`matrix-token`) and the daemon keeps
  # its matrix-sdk store. Shared by the `main` account entry below and
  # the path-watcher glob at the bottom of this file.
  stateDir = "/agents/${userName}/state";
  accounts = config.services.hyperhive.agent.matrixAccounts;
  # **The enable signal.** Matrix is on for this agent exactly when it has at
  # least one account, because an account is the only thing the daemon has to
  # do: no account, no Client, no sync, no tool surface worth injecting.
  #
  # This is not trivially true even though the module declares `main` itself:
  # that definition is gated on `matrix.url != null` (see below), which is the
  # per-agent "does this agent have a homeserver to reach" fact. So an agent the
  # hive handed no homeserver URL, whose operator declared no external account
  # either, has an empty set here and gets none of the units — the case the
  # deleted `matrix.enable = false` used to express.
  #
  # No cycle: `matrixAccounts`'s own definition reads `matrix.url`, never this
  # binding, so the `mkIf`s below may read the merged option value freely.
  matrixEnabled = accounts != { };
  # Rasterize the operator-set agent icon (`services.hyperhive.agent.icon`, an SVG) to a
  # 512x512 PNG so the matrix daemon can upload it as each account's avatar
  # over the live authenticated Client (see hive-matrix-mcp::client::sync_avatar).
  # Only forced when an icon is configured — the `HIVE_ICON_PNG` daemon-env
  # entry is gated on `services.hyperhive.agent.icon != null`, so this binding stays lazy
  # when no icon is set.
  iconPng = pkgs.runCommand "hive-agent-icon.png" { nativeBuildInputs = [ pkgs.librsvg ]; } ''
    rsvg-convert -f png -w 512 -h 512 ${config.services.hyperhive.agent.icon} -o $out
  '';
in
{
  options.services.hyperhive.agent.matrix.url = lib.mkOption {
    type = lib.types.nullOr lib.types.str;
    default = null;
    example = "https://matrix.darkest.space";
    description = ''
      Matrix homeserver URL the agent's `hive-matrix-daemon` connects
      to. hive-c0re writes this per agent from the hive's own
      isolation-aware URL (`gatewayHost`'s vhost via the gateway,
      `chat.<swarm-domain>` by default), so a
      generated agent config always carries a real value; set it by
      hand only when an agent should talk to an external homeserver
      instead (a federation-only setup, or a remote hive's tuwunel
      reached over a vpn).

      **`null` means "no matrix", not "guess one".** There is
      deliberately no loopback default: the homeserver may run on a
      different host from the agents, and inside an agent's network
      namespace `localhost` reaches the agent rather than the
      homeserver, so a default would be a value that builds fine and
      then talks to the wrong machine. An absent integration, never a
      misdirected one.

      `null` is also this agent's **matrix off switch**, and the
      replacement for the `services.hyperhive.agent.matrix.enable`
      boolean that used to exist: the hive-internal `main` account in
      `services.hyperhive.agent.matrixAccounts` is declared from this
      URL, so `null` leaves that set empty and the whole integration —
      daemon unit, path watcher, injected MCP entry — is not generated
      at all. Declaring an external account with its own `homeserver`
      turns matrix back on without a hive homeserver, which is the
      honest reading of that config.
    '';
  };

  options.services.hyperhive.agent.matrixAccounts = lib.mkOption {
    type = lib.types.attrsOf (
      lib.types.submodule {
        options = {
          tokenFile = lib.mkOption {
            type = lib.types.str;
            example = "/agents/dmatrix/state/matrix-token-ccc";
            description = ''
              Path to this account's bearer-token file. The daemon reads
              the token from here to restore the matrix session; how the
              file gets populated is the provisioner's concern
              (hive-c0re for the hive-internal `main` account, an
              operator-supplied secret for an external one). The daemon
              skips an extra account whose token file is absent, and
              exits cleanly to wait on the path watcher when `main`'s is.
            '';
          };
          sessionDir = lib.mkOption {
            type = lib.types.str;
            example = "/agents/dmatrix/state/matrix-sdk-state-ccc";
            description = ''
              Per-account matrix-sdk sqlite store directory (crypto keys
              + event cache). Must differ between accounts so their
              sessions do not collide.
            '';
          };
          homeserver = lib.mkOption {
            type = lib.types.nullOr lib.types.str;
            default = null;
            example = "https://matrix.example.org";
            description = ''
              Homeserver URL for this account. When null (the default),
              the account falls back to `services.hyperhive.agent.matrix.url`. Set it for
              an account on a different homeserver than the agent's
              default (e.g. an external public-matrix account).
            '';
          };
        };
      }
    );
    default = { };
    example = lib.literalExpression ''
      {
        ccc = {
          tokenFile = "/agents/dmatrix/state/matrix-token-ccc";
          sessionDir = "/agents/dmatrix/state/matrix-sdk-state-ccc";
          homeserver = "https://matrix.example.org";
        };
      }
    '';
    description = ''
      Every matrix account served by the single `hive-matrix-daemon`
      (one matrix-sdk Client + sync loop each). The attribute name keys
      each account (unique by construction) and is the handle the matrix
      MCP tools target via their `account` argument.

      **This set is also the enable signal for per-agent matrix** —
      there is no separate boolean. A non-empty set means the harness:

      - runs `hive-matrix-daemon` as a systemd unit that holds a
        matrix-sdk Client + sync per account against that account's
        homeserver (`homeserver`, else
        `services.hyperhive.agent.matrix.url`). The daemon auto-skips an
        account whose URL or token file is missing, and a `systemd.paths`
        watcher restarts it the moment hive-c0re provisions the token
        (same path-trigger shape as `forge-avatar-sync`).
      - exposes the matrix tool surface (send_message, send_dm,
        send_reaction, send_reply, mark_read, list_rooms,
        list_room_members, read_room) to claude via an auto-injected
        `extraMcpServers.matrix` entry pointed at the daemon's own
        streamable-http listener (`services.hyperhive.agent.mcp.matrixHttpPort`) — no
        stdio bridge, no per-turn respawn, same shape as the built-in
        hyperhive surface and `hive-bash-daemon`.
      - wakes the agent on incoming room events via a short teaser
        Wake signal (`[matrix] <sender> in <room>: <first 100c>…`)
        to the hyperhive control socket; the full event stays
        unread server-side until `read_room` consumes it.

      An **empty** set is an agent with no matrix at all: none of those
      three exist. That is the state an agent reaches by having no
      homeserver (`services.hyperhive.agent.matrix.url = null`) and no
      account of its own, and it replaces the removed
      `services.hyperhive.agent.matrix.enable = false`.

      The **hive-internal account is the primary whenever it exists**: it
      is named `main`, and this module declares it for you from
      `services.hyperhive.agent.matrix.url` + `<state>/matrix-token` +
      `<state>/matrix-sdk-state` — so it is present exactly when that URL
      is non-null, which on a real hive is always (hive-c0re renders it
      per agent). It is the account a tool call acts as when it omits
      `account`. It is an ordinary entry of this option
      like any other, so it shows up in the account list --- what you
      add here are the *further* accounts (e.g. an external
      public-matrix account). Its `tokenFile` stays pinned to
      `<state>/matrix-token` (an assertion; that is the one path
      hive-c0re provisions the hive-internal token to), and the
      dashboard's link-account route refuses to create an account named
      `main` --- the entry belongs to the module, not to a provisioner.

      Leave it alone (the default) for the common single-account case:
      the agent then has only `main`. The whole set is serialized to the
      daemon's `HIVE_MATRIX_ACCOUNTS` environment variable, `main`
      first.
    '';
  };

  options.services.hyperhive.agent.mcp.matrixHttpPort = lib.mkOption {
    type = lib.types.port;
    default = 8792;
    example = 8793;
    description = ''
      Loopback port `hive-matrix-daemon` serves its MCP tools
      (`send_message`, `list_rooms`, `read_room`, …) on. Same shape as
      `services.hyperhive.agent.mcp.bashHttpPort`: HTTP is the *sole* transport (no
      stdio bridge — the daemon that owns the matrix-sdk `Client`
      registry serves the MCP tools directly in-process),
      `Restart = "always"` keeps the listener self-healing, and
      loopback-only binding means no auth token is needed (same
      `allowed_hosts` reasoning as `services.hyperhive.agent.mcp.httpPort`). Safe as a
      single fixed default across all agents (private per-container
      network namespace — see docs/networking/network.md).
    '';
  };

  config = {
    assertions = [
      # The "extras require `matrix.enable`" assertion that used to head this
      # list is gone with the option: a non-empty account set is now what
      # enables matrix, so the condition it checked has become the definition
      # of the thing it was checking. An operator declaring only an external
      # account, with no hive homeserver, is a config this module now renders
      # rather than rejects — matrix on, no `main`.
      #
      # `main` is not a forbidden key --- this module declares it
      # itself (see the `matrixAccounts.main` definition below), so the
      # name must be allowed. What stays rejected is retargeting *its
      # token file*: hive-c0re writes the hive-internal account's token
      # to `<state>/matrix-token` and nowhere else, so an override there
      # is an account that evaluates fine and then never restores. The
      # other two fields are free to override (a `mkDefault` each).
      #
      # Guarded on `? main` rather than on an enable flag: `main` is absent
      # whenever `matrix.url` is null, and an unguarded `.main.tokenFile`
      # would throw on exactly those agents instead of passing vacuously.
      {
        assertion = !(accounts ? main) || accounts.main.tokenFile == "${stateDir}/matrix-token";
        message =
          "services.hyperhive.agent.matrixAccounts.main.tokenFile must stay "
          + "\"${stateDir}/matrix-token\" --- that is where hive-c0re provisions the "
          + "hive-internal account's token. Declare a separate account instead of "
          + "pointing `main` elsewhere.";
      }
      # Token files must land at the `matrix-token*` name the daemon
      # path-watcher globs (`matrix-token*` inside this agent's own state
      # dir), or the account never gets picked up live (it loads only on a
      # full daemon restart).
      # Enforce the basename prefix so a deviating name (e.g.
      # `matrix-catgirl-token`) is caught at build time, not silently.
      {
        assertion = lib.all (a: lib.hasPrefix "matrix-token" (baseNameOf a.tokenFile)) (
          lib.attrValues accounts
        );
        message =
          "every services.hyperhive.agent.matrixAccounts.<name>.tokenFile basename must start with "
          + "\"matrix-token\" so the daemon path-watcher glob "
          + "(matrix-token* in the agent's state dir) picks it up live. Offending: "
          + lib.concatStringsSep ", " (
            lib.mapAttrsToList (n: a: "${n}=${baseNameOf a.tokenFile}") (
              lib.filterAttrs (_n: a: !lib.hasPrefix "matrix-token" (baseNameOf a.tokenFile)) accounts
            )
          )
          + ".";
      }
    ];

    # The hive-internal account as an ordinary `matrixAccounts` entry,
    # rather than something the daemon conjures behind the option's
    # back: `matrixAccounts` is the list of *all* this agent's accounts,
    # so the one it always has belongs in it. `mkDefault` per field so an
    # operator can retarget e.g. the homeserver without a
    # conflicting-definition error (the token file is pinned by an
    # assertion above, since hive-c0re owns that path).
    #
    # ⚠️ Gated on the homeserver URL, and that gate is what keeps `matrixEnabled`
    # from being trivially true for every agent in the hive. A `main` with no
    # homeserver is an account the daemon can never log in as, so declaring one
    # unconditionally would enable matrix everywhere and inject a tool surface
    # backed by a permanently no-opping daemon. On a real hive hive-c0re renders
    # this URL per agent (meta.rs's `FORWARDED_VAR_OPTIONS`), so the common case
    # is still "every agent has `main`".
    services.hyperhive.agent.matrixAccounts =
      lib.mkIf (config.services.hyperhive.agent.matrix.url != null)
        {
          main = {
            tokenFile = lib.mkDefault "${stateDir}/matrix-token";
            sessionDir = lib.mkDefault "${stateDir}/matrix-sdk-state";
            homeserver = lib.mkDefault config.services.hyperhive.agent.matrix.url;
          };
        };

    # Auto-inject the matrix MCP entry alongside the bash entry from
    # ./mcp.nix. `lib.mkDefault` so the operator's own agent.nix can
    # override it. Points at the daemon's own persistent
    # streamable-http listener — no stdio bridge, no per-turn spawn.
    services.hyperhive.agent.extraMcpServers = lib.mkIf matrixEnabled {
      matrix = lib.mkDefault {
        type = "http";
        url = "http://127.0.0.1:${toString config.services.hyperhive.agent.mcp.matrixHttpPort}/mcp";
        allowedTools = [ "*" ];
      };
    };

    # Long-running matrix-sdk client + sync per agent. Serves the MCP
    # tools directly over streamable-http + emits hyperhive wake
    # signals on incoming room events via `/run/hive/mcp.sock`. See
    # `docs/agent-lifecycle/persistence.md::Matrix per-agent daemon + token-arrival
    # trigger` for the first-boot-ordering rationale.
    systemd.services.hive-matrix-daemon = lib.mkIf matrixEnabled {
      description = "long-running matrix-sdk Client + MCP daemon";
      wantedBy = [ "multi-user.target" ];
      before = [ "hive-agent.service" ];
      after = [ "network-online.target" ];
      wants = [ "network-online.target" ];
      environment = {
        # In-agent todo socket the harness serves (loose-ends v2): the
        # matrix sweep pushes unread-room + pending-invite todos here
        # instead of firing wakes at hive-c0re's mcp.sock.
        HIVE_AGENT_SOCKET = "/run/hive-agent/${userName}/agent.sock";
        RUST_LOG = "info";
      }
      # Homeserver URL. hive-c0re writes this option per agent from the
      # hive's own gateway URL (`gatewayHost`'s vhost, `chat.<swarm-domain>`
      # by default — agents run in a private
      # netns and cannot reach host loopback), so on a real hive it is
      # always set; `null` is the honest "this agent has no homeserver"
      # and leaves the daemon without one, which it treats like a missing
      # token and no-ops. Nothing here falls back to loopback: that would
      # be a value that evaluates fine and then addresses the agent's own
      # netns instead of the homeserver.
      // lib.optionalAttrs (config.services.hyperhive.agent.matrix.url != null) {
        HIVE_MATRIX_URL = config.services.hyperhive.agent.matrix.url;
      }
      # Serialize the whole account set --- `main` included --- to the
      # JSON the daemon parses (`accounts::configured`). Each entry is in
      # the daemon's `AccountCfg` serde shape: name (the attr key) /
      # token_file / state_dir / optional homeserver. The daemon hoists
      # `main` to primary wherever the attr key sorted, and falls back to
      # synthesizing it from the per-agent paths only when this JSON
      # carries no `main` --- which is how an agent whose harness
      # predates this entry keeps working.
      #
      # Unconditional, not `optionalAttrs (accounts != {})`: a non-empty set is
      # what generated this unit at all, so the guard could only ever be true.
      // {
        HIVE_MATRIX_ACCOUNTS = builtins.toJSON (
          lib.mapAttrsToList (
            name: a:
            {
              inherit name;
              token_file = a.tokenFile;
              state_dir = a.sessionDir;
            }
            // lib.optionalAttrs (a.homeserver != null) { inherit (a) homeserver; }
          ) accounts
        );
      }
      # Rasterized agent icon path for the daemon's avatar sync. Only set
      # when an icon is configured; absent → the daemon skips avatar setting
      # (hive-matrix-mcp::client::sync_avatar returns early on unset env).
      // lib.optionalAttrs (config.services.hyperhive.agent.icon != null) {
        HIVE_ICON_PNG = "${iconPng}";
      };
      serviceConfig = {
        ExecStart = "${config.services.hyperhive.agent.packages.hive-matrix-daemon}/bin/hive-matrix-daemon --http 127.0.0.1:${toString config.services.hyperhive.agent.mcp.matrixHttpPort}";
        SyslogIdentifier = "hive-matrix-daemon";
        # `on-failure`, not `always`: the daemon deliberately exits 0
        # (a clean, non-failure exit) when no token is provisioned yet
        # (see the module doc above) — the `systemd.paths` watcher
        # below re-fires it the moment hive-c0re provisions one,
        # instead of `always` busy-looping every `RestartSec` until
        # then. Once a token exists this is no different from
        # `hive-bash-daemon`'s reasoning (a down window loses the MCP
        # tools with no stdio fallback) — a genuine crash is a
        # non-zero exit, which `on-failure` already restarts.
        Restart = "on-failure";
        RestartSec = 5;
        User = userName;
        Group = userName;
      };
    };

    # Re-fire the daemon when the matrix token appears (hive-c0re
    # provisions it after agent containers come up). Without this
    # the daemon would exit 0 silently on first boot and the MCP
    # would have no backend until next restart. See
    # `docs/agent-lifecycle/persistence.md` (same section as above).
    systemd.paths.hive-matrix-daemon = lib.mkIf matrixEnabled {
      description = "trigger hive-matrix-daemon when a matrix token appears";
      wantedBy = [ "multi-user.target" ];
      # `matrix-token*` (not just `matrix-token`) so a secondary
      # multi-account token (e.g. `matrix-token-ccc`) landing also
      # re-fires the daemon to pick up the freshly-provisioned account.
      #
      # ⚠️ This agent's own state dir, not a glob over `/agents/*/`. Every
      # agent's state dir is visible from inside every container, so a
      # wildcard is satisfied by a sibling's token — and this daemon exits 0
      # when it has no token of its own (see `Restart = "on-failure"`
      # above), so the unit deactivates, the path unit re-arms, the
      # sibling's token still matches, and it fires again until the start
      # limit stops it. Scoped to this agent, the condition is false exactly
      # when the daemon would have nothing to do.
      pathConfig.PathExistsGlob = "${stateDir}/matrix-token*";
    };
  };
}