# Per-agent matrix integration: the `hyperhive.matrix.*` +
# `hyperhive.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.
{
  pkgs,
  lib,
  config,
  ...
}:
let
  userName = config.hyperhive.user.name;
  # Rasterize the operator-set agent icon (`hyperhive.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 `hyperhive.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.hyperhive.icon} -o $out
  '';
in
{
  options.hyperhive.matrix.enable = lib.mkOption {
    type = lib.types.bool;
    default = true;
    description = ''
      Enable per-agent matrix integration via `hive-matrix-daemon`.
      When true (the default), the harness:

      - runs `hive-matrix-daemon` as a systemd unit that holds a
        matrix-sdk Client + sync against the homeserver named by
        `HIVE_MATRIX_URL` (see `hyperhive.matrix.url` — there is no
        default, since an agent's own netns makes a loopback guess
        wrong). The daemon auto-skips when that URL or
        `<state>/matrix-token` 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 (`hyperhive.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.

      Set to `false` for agents that should NOT have matrix tools at
      all (e.g. agents on a host without `hyperhive.matrix.enable` on
      the meta side). When token file is absent the daemon and MCP
      both no-op cleanly anyway, so `false` is rarely necessary.
    '';
  };

  options.hyperhive.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 (`matrix.<domain>` via the gateway), 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. When this is `null` the daemon
      is left without a homeserver and no-ops, exactly as it does when
      the token file is absent --- an absent integration, never a
      misdirected one.
    '';
  };

  options.hyperhive.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 (an
              operator-supplied secret for an external account). The
              daemon skips an extra account whose token file is absent.
            '';
          };
          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 `hyperhive.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 = ''
      Declare *additional* matrix accounts served by the single
      `hive-matrix-daemon` (one matrix-sdk Client + sync loop each),
      beyond the agent's built-in hive-internal account. The
      attribute name keys each account (unique by construction) and is
      the handle the matrix MCP tools target via their `account`
      argument.

      The **hive-internal account is always present and is the primary**:
      it is named `main`, synthesized by the daemon from
      `hyperhive.matrix.url` + `<state>/matrix-token` +
      `<state>/matrix-sdk-state`, and is the account a tool call acts as
      when it omits `account`. You never declare it here --- this option
      is only for the extras (e.g. an external public-matrix account).

      Leave empty (the default) for the common single-account case: the
      agent then has only `main`. When non-empty, the extras are
      serialized to the daemon's `HIVE_MATRIX_ACCOUNTS` environment
      variable and the daemon appends them after `main`. Requires
      `hyperhive.matrix.enable` (there is no `main` to extend otherwise).
    '';
  };

  options.hyperhive.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
      `hyperhive.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 `hyperhive.mcp.httpPort`). Safe as a
      single fixed default across all agents (private per-container
      network namespace — see docs/network.md).
    '';
  };

  config = {
    assertions = [
      # Extra matrix accounts only make sense alongside the hive-internal
      # `main` account they extend, which exists only when matrix is
      # enabled.
      {
        assertion = config.hyperhive.matrixAccounts == { } || config.hyperhive.matrix.enable;
        message =
          "hyperhive.matrixAccounts requires hyperhive.matrix.enable = true "
          + "(the extras extend the hive-internal `main` account, which only "
          + "exists when matrix is enabled).";
      }
      # `main` is reserved for the synthesized hive-internal account; a
      # declared extra by that name would silently collide with it.
      {
        assertion = !builtins.hasAttr "main" config.hyperhive.matrixAccounts;
        message =
          "hyperhive.matrixAccounts cannot contain a key named \"main\" "
          + "--- that name is reserved for the hive-internal account.";
      }
      # Token files must land at the `matrix-token*` name the daemon
      # path-watcher globs (`/agents/*/state/matrix-token*`), 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 config.hyperhive.matrixAccounts
        );
        message =
          "every hyperhive.matrixAccounts.<name>.tokenFile basename must start with "
          + "\"matrix-token\" so the daemon path-watcher glob "
          + "(/agents/*/state/matrix-token*) 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)
              ) config.hyperhive.matrixAccounts
            )
          )
          + ".";
      }
    ];

    # 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.
    hyperhive.extraMcpServers = lib.mkIf config.hyperhive.matrix.enable {
      matrix = lib.mkDefault {
        type = "http";
        url = "http://127.0.0.1:${toString config.hyperhive.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/persistence.md::Matrix per-agent daemon + token-arrival
    # trigger` for the first-boot-ordering rationale.
    systemd.services.hive-matrix-daemon = lib.mkIf config.hyperhive.matrix.enable {
      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/${userName}/agent.sock";
        RUST_LOG = "info";
      }
      # Homeserver URL. hive-c0re writes this option per agent from the
      # hive's own `matrix.<domain>` gateway URL (agents run in a private
      # netns and cannot reach host loopback), so on a real hive it is
      # always set; `null` is the honest "this agent has no homeserver"
      # and leaves the daemon without one, which it treats like a missing
      # token and no-ops. Nothing here falls back to loopback: that would
      # be a value that evaluates fine and then addresses the agent's own
      # netns instead of the homeserver.
      // lib.optionalAttrs (config.hyperhive.matrix.url != null) {
        HIVE_MATRIX_URL = config.hyperhive.matrix.url;
      }
      # Multi-account: serialize the *extra* accounts to the JSON the
      # daemon parses (`accounts::configured`). Only set when extras are
      # declared; the daemon always synthesizes the primary `main`
      # (hive-internal) account itself from the per-agent paths and
      # prepends it, so we emit extras only. Each entry is in the
      # daemon's `AccountCfg` serde shape: name (the attr key) /
      # token_file / state_dir / optional homeserver.
      // lib.optionalAttrs (config.hyperhive.matrixAccounts != { }) {
        HIVE_MATRIX_ACCOUNTS = builtins.toJSON (
          lib.mapAttrsToList (
            name: a:
            {
              inherit name;
              token_file = a.tokenFile;
              state_dir = a.sessionDir;
            }
            // lib.optionalAttrs (a.homeserver != null) { inherit (a) homeserver; }
          ) config.hyperhive.matrixAccounts
        );
      }
      # Rasterized agent icon path for the daemon's avatar sync. Only set
      # when an icon is configured; absent → the daemon skips avatar setting
      # (hive-matrix-mcp::client::sync_avatar returns early on unset env).
      // lib.optionalAttrs (config.hyperhive.icon != null) {
        HIVE_ICON_PNG = "${iconPng}";
      };
      serviceConfig = {
        ExecStart = "${config.hyperhive.packages.hive-matrix-daemon}/bin/hive-matrix-daemon --http 127.0.0.1:${toString config.hyperhive.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/persistence.md` (same section as above).
    systemd.paths.hive-matrix-daemon = lib.mkIf config.hyperhive.matrix.enable {
      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.
      pathConfig.PathExistsGlob = "/agents/*/state/matrix-token*";
    };
  };
}