import type { OpenClawConfig } from "../config/types.openclaw.js";
import { callGateway as defaultCallGateway } from "../gateway/call.js";
import { resolveAgentIdFromSessionKey } from "../routing/session-key.js";
import {
  normalizeLowercaseStringOrEmpty,
  normalizeOptionalString,
} from "../shared/string-coerce.js";

type GatewayCaller = typeof defaultCallGateway;

let callGatewayForListSpawned: GatewayCaller = defaultCallGateway;

/** Test hook: must stay aligned with `sessions-resolution` `testing.setDepsForTest`. */
export const sessionVisibilityGatewayTesting = {
  setCallGatewayForListSpawned(overrides?: GatewayCaller) {
    callGatewayForListSpawned = overrides ?? defaultCallGateway;
  },
};

export type SessionToolsVisibility = "self" | "tree" | "agent" | "all";

export type AgentToAgentPolicy = {
  enabled: boolean;
  matchesAllow: (agentId: string) => boolean;
  isAllowed: (requesterAgentId: string, targetAgentId: string) => boolean;
};

export type SessionAccessAction = "history" | "send" | "list" | "status";

export type SessionAccessResult =
  | { allowed: true }
  | { allowed: false; error: string; status: "forbidden" };

export type SessionVisibilityRow = {
  key: string;
  agentId?: string;
  ownerSessionKey?: string;
  spawnedBy?: string;
  parentSessionKey?: string;
};

export async function listSpawnedSessionKeys(params: {
  requesterSessionKey: string;
  limit?: number;
}): Promise<Set<string>> {
  const limit =
    typeof params.limit === "number" && Number.isFinite(params.limit)
      ? Math.max(1, Math.floor(params.limit))
      : undefined;
  try {
    const list = await callGatewayForListSpawned<{ sessions: Array<{ key?: unknown }> }>({
      method: "sessions.list",
      params: {
        includeGlobal: false,
        includeUnknown: false,
        ...(limit !== undefined ? { limit } : {}),
        spawnedBy: params.requesterSessionKey,
      },
    });
    const sessions = Array.isArray(list?.sessions) ? list.sessions : [];
    const keys = sessions.map((entry) => normalizeOptionalString(entry?.key) ?? "").filter(Boolean);
    return new Set(keys);
  } catch {
    return new Set();
  }
}

export function resolveSessionToolsVisibility(cfg: OpenClawConfig): SessionToolsVisibility {
  const raw = (cfg.tools as { sessions?: { visibility?: unknown } } | undefined)?.sessions
    ?.visibility;
  const value = normalizeLowercaseStringOrEmpty(raw);
  if (value === "self" || value === "tree" || value === "agent" || value === "all") {
    return value;
  }
  return "tree";
}

export function resolveEffectiveSessionToolsVisibility(params: {
  cfg: OpenClawConfig;
  sandboxed: boolean;
}): SessionToolsVisibility {
  const visibility = resolveSessionToolsVisibility(params.cfg);
  if (!params.sandboxed) {
    return visibility;
  }
  const sandboxClamp = params.cfg.agents?.defaults?.sandbox?.sessionToolsVisibility ?? "spawned";
  if (sandboxClamp === "spawned" && visibility !== "tree") {
    return "tree";
  }
  return visibility;
}

export function resolveSandboxSessionToolsVisibility(cfg: OpenClawConfig): "spawned" | "all" {
  return cfg.agents?.defaults?.sandbox?.sessionToolsVisibility ?? "spawned";
}

export function createAgentToAgentPolicy(cfg: OpenClawConfig): AgentToAgentPolicy {
  const routingA2A = cfg.tools?.agentToAgent;
  const enabled = routingA2A?.enabled === true;
  const allowPatterns = Array.isArray(routingA2A?.allow) ? routingA2A.allow : [];
  const matchesAllow = (agentId: string) => {
    if (allowPatterns.length === 0) {
      return true;
    }
    return allowPatterns.some((pattern) => {
      const raw =
        normalizeOptionalString(typeof pattern === "string" ? pattern : String(pattern ?? "")) ??
        "";
      if (!raw) {
        return false;
      }
      if (raw === "*") {
        return true;
      }
      if (!raw.includes("*")) {
        return raw === agentId;
      }
      const escaped = raw.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
      const re = new RegExp(`^${escaped.replaceAll("\\*", ".*")}$`, "i");
      return re.test(agentId);
    });
  };
  const isAllowed = (requesterAgentId: string, targetAgentId: string) => {
    if (requesterAgentId === targetAgentId) {
      return true;
    }
    if (!enabled) {
      return false;
    }
    return matchesAllow(requesterAgentId) && matchesAllow(targetAgentId);
  };
  return { enabled, matchesAllow, isAllowed };
}

function actionPrefix(action: SessionAccessAction): string {
  if (action === "history") {
    return "Session history";
  }
  if (action === "send") {
    return "Session send";
  }
  if (action === "status") {
    return "Session status";
  }
  return "Session list";
}

function a2aDisabledMessage(action: SessionAccessAction): string {
  if (action === "history") {
    return "Agent-to-agent history is disabled. Set tools.agentToAgent.enabled=true to allow cross-agent access.";
  }
  if (action === "send") {
    return "Agent-to-agent messaging is disabled. Set tools.agentToAgent.enabled=true to allow cross-agent sends.";
  }
  if (action === "status") {
    return "Agent-to-agent status is disabled. Set tools.agentToAgent.enabled=true to allow cross-agent access.";
  }
  return "Agent-to-agent listing is disabled. Set tools.agentToAgent.enabled=true to allow cross-agent visibility.";
}

function a2aDeniedMessage(action: SessionAccessAction): string {
  if (action === "history") {
    return "Agent-to-agent history denied by tools.agentToAgent.allow.";
  }
  if (action === "send") {
    return "Agent-to-agent messaging denied by tools.agentToAgent.allow.";
  }
  if (action === "status") {
    return "Agent-to-agent status denied by tools.agentToAgent.allow.";
  }
  return "Agent-to-agent listing denied by tools.agentToAgent.allow.";
}

function crossVisibilityMessage(action: SessionAccessAction): string {
  if (action === "history") {
    return "Session history visibility is restricted. Set tools.sessions.visibility=all to allow cross-agent access.";
  }
  if (action === "send") {
    return "Session send visibility is restricted. Set tools.sessions.visibility=all to allow cross-agent access.";
  }
  if (action === "status") {
    return "Session status visibility is restricted. Set tools.sessions.visibility=all to allow cross-agent access.";
  }
  return "Session list visibility is restricted. Set tools.sessions.visibility=all to allow cross-agent access.";
}

function selfVisibilityMessage(action: SessionAccessAction): string {
  return `${actionPrefix(action)} visibility is restricted to the current session (tools.sessions.visibility=self).`;
}

function treeVisibilityMessage(action: SessionAccessAction): string {
  return `${actionPrefix(action)} visibility is restricted to the current session tree (tools.sessions.visibility=tree).`;
}

export function createSessionVisibilityChecker(params: {
  action: SessionAccessAction;
  requesterSessionKey: string;
  visibility: SessionToolsVisibility;
  a2aPolicy: AgentToAgentPolicy;
  spawnedKeys: Set<string> | null;
}): { check: (targetSessionKey: string) => SessionAccessResult } {
  const spawnedKeys = params.spawnedKeys;
  const rowChecker = createSessionVisibilityRowChecker({
    action: params.action,
    requesterSessionKey: params.requesterSessionKey,
    visibility: params.visibility,
    a2aPolicy: params.a2aPolicy,
  });

  const check = (targetSessionKey: string): SessionAccessResult => {
    const isSpawnedSession = spawnedKeys?.has(targetSessionKey) === true;
    return rowChecker.check({
      key: targetSessionKey,
      spawnedBy: isSpawnedSession ? params.requesterSessionKey : undefined,
    });
  };

  return { check };
}

function rowOwnedByRequester(row: SessionVisibilityRow, requesterSessionKey: string): boolean {
  return (
    row.ownerSessionKey === requesterSessionKey ||
    row.spawnedBy === requesterSessionKey ||
    row.parentSessionKey === requesterSessionKey
  );
}

export function createSessionVisibilityRowChecker(params: {
  action: SessionAccessAction;
  requesterSessionKey: string;
  visibility: SessionToolsVisibility;
  a2aPolicy: AgentToAgentPolicy;
}): { check: (row: SessionVisibilityRow) => SessionAccessResult } {
  const requesterAgentId = resolveAgentIdFromSessionKey(params.requesterSessionKey);

  const check = (row: SessionVisibilityRow): SessionAccessResult => {
    const targetSessionKey = row.key;
    const targetAgentId = row.agentId ?? resolveAgentIdFromSessionKey(targetSessionKey);
    const isRequesterSession =
      targetSessionKey === params.requesterSessionKey || targetSessionKey === "current";
    const isRequesterOwned = rowOwnedByRequester(row, params.requesterSessionKey);
    // Row ownership is stronger than agent ids: ACP children may use a backend
    // agent id while still belonging to the requester that spawned them.
    if (
      !isRequesterSession &&
      isRequesterOwned &&
      (params.visibility === "tree" || params.visibility === "all")
    ) {
      return { allowed: true };
    }
    const isCrossAgent = targetAgentId !== requesterAgentId;
    if (isCrossAgent) {
      if (params.visibility !== "all") {
        return {
          allowed: false,
          status: "forbidden",
          error: crossVisibilityMessage(params.action),
        };
      }
      if (!params.a2aPolicy.enabled) {
        return {
          allowed: false,
          status: "forbidden",
          error: a2aDisabledMessage(params.action),
        };
      }
      if (!params.a2aPolicy.isAllowed(requesterAgentId, targetAgentId)) {
        return {
          allowed: false,
          status: "forbidden",
          error: a2aDeniedMessage(params.action),
        };
      }
      return { allowed: true };
    }

    if (params.visibility === "self" && !isRequesterSession) {
      return {
        allowed: false,
        status: "forbidden",
        error: selfVisibilityMessage(params.action),
      };
    }

    if (params.visibility === "tree" && !isRequesterSession && !isRequesterOwned) {
      return {
        allowed: false,
        status: "forbidden",
        error: treeVisibilityMessage(params.action),
      };
    }

    return { allowed: true };
  };

  return { check };
}

export async function createSessionVisibilityGuard(params: {
  action: SessionAccessAction;
  requesterSessionKey: string;
  visibility: SessionToolsVisibility;
  a2aPolicy: AgentToAgentPolicy;
}): Promise<{
  check: (targetSessionKey: string) => SessionAccessResult;
}> {
  // Listing already has row ownership metadata; direct key actions still need
  // this lookup until every caller can pass a normalized session row.
  const spawnedKeys =
    params.action !== "list" && (params.visibility === "tree" || params.visibility === "all")
      ? await listSpawnedSessionKeys({ requesterSessionKey: params.requesterSessionKey })
      : null;
  return createSessionVisibilityChecker({
    action: params.action,
    requesterSessionKey: params.requesterSessionKey,
    visibility: params.visibility,
    a2aPolicy: params.a2aPolicy,
    spawnedKeys,
  });
}