import { dbGlobal } from "drizzle-pkg/lib/db";
import { agentTools } from "drizzle-pkg/lib/schema/agent-tool";
import { eq, asc } from "drizzle-orm";
import { tool, jsonSchema } from "ai";
import { z } from "zod";

import { registerToolType, getExecutor, type ToolContext, type ToolResult } from "./registry";
import { writeToolLog } from "./log";
import { parseFetchConfig, DEFAULT_FETCH_CONFIG } from "./executors/fetch/config";
import { fetchExecutor } from "./executors/fetch/fetch";

// 立即注册 fetch 工具类型，确保在任何 execute 调用前完成
registerToolType("fetch", fetchExecutor);

// fetch 工具的固定 input schema
const FETCH_INPUT_SCHEMA = z.object({
  url: z.string().describe("要抓取的 URL"),
});

export type AgentToolRow = typeof agentTools.$inferSelect;

export interface CreateAgentToolInput {
  name: string;
  slug: string;
  description: string;
  type: string;
  config: Record<string, unknown>;
  enabled?: boolean;
  sortOrder?: number;
}

export interface UpdateAgentToolInput {
  name?: string;
  slug?: string;
  description?: string;
  type?: string;
  config?: Record<string, unknown>;
  enabled?: boolean;
  sortOrder?: number;
}

export async function listAgentTools(): Promise<AgentToolRow[]> {
  return dbGlobal.select().from(agentTools).orderBy(asc(agentTools.sortOrder), asc(agentTools.createdAt));
}

export async function getAgentToolById(id: string): Promise<AgentToolRow | null> {
  const rows = await dbGlobal.select().from(agentTools).where(eq(agentTools.id, id)).limit(1);
  return rows[0] ?? null;
}

export async function getAgentToolBySlug(slug: string): Promise<AgentToolRow | null> {
  const rows = await dbGlobal.select().from(agentTools).where(eq(agentTools.slug, slug)).limit(1);
  return rows[0] ?? null;
}

function generateId(): string {
  return `at_${Date.now().toString(36)}_${Math.random().toString(36).slice(2, 8)}`;
}

function validateConfig(type: string, config: Record<string, unknown>): Record<string, unknown> {
  if (type === "fetch") {
    return parseFetchConfig(config);
  }
  return config;
}

export async function createAgentTool(input: CreateAgentToolInput): Promise<AgentToolRow> {
  const existing = await getAgentToolBySlug(input.slug);
  if (existing) {
    throw new Error(`slug 已存在: ${input.slug}`);
  }
  const validatedConfig = validateConfig(input.type, input.config);
  const id = generateId();
  await dbGlobal.insert(agentTools).values({
    id,
    name: input.name,
    slug: input.slug,
    description: input.description,
    type: input.type,
    config: JSON.stringify(validatedConfig),
    enabled: input.enabled === false ? 0 : 1,
    sortOrder: input.sortOrder ?? 0,
  });
  const row = await getAgentToolById(id);
  if (!row) throw new Error("创建后查询失败");
  return row;
}

export async function updateAgentTool(id: string, input: UpdateAgentToolInput): Promise<AgentToolRow | null> {
  const existing = await getAgentToolById(id);
  if (!existing) return null;

  if (input.slug && input.slug !== existing.slug) {
    const slugConflict = await getAgentToolBySlug(input.slug);
    if (slugConflict) {
      throw new Error(`slug 已存在: ${input.slug}`);
    }
  }

  const updates: Partial<AgentToolRow> = {};
  if (input.name !== undefined) updates.name = input.name;
  if (input.slug !== undefined) updates.slug = input.slug;
  if (input.description !== undefined) updates.description = input.description;
  if (input.type !== undefined) updates.type = input.type;
  if (input.config !== undefined) {
    const typeToValidate = input.type ?? existing.type;
    updates.config = JSON.stringify(validateConfig(typeToValidate, input.config));
  }
  if (input.enabled !== undefined) updates.enabled = input.enabled ? 1 : 0;
  if (input.sortOrder !== undefined) updates.sortOrder = input.sortOrder;

  if (Object.keys(updates).length === 0) return existing;

  await dbGlobal.update(agentTools).set(updates).where(eq(agentTools.id, id));
  return getAgentToolById(id);
}

export async function deleteAgentTool(id: string): Promise<void> {
  await dbGlobal.delete(agentTools).where(eq(agentTools.id, id));
}

export async function executeAgentTool(
  id: string,
  input: unknown,
  userId: number | null,
): Promise<ToolResult> {
  const agentTool = await getAgentToolById(id);
  if (!agentTool) {
    return {
      success: false,
      data: null,
      error: `工具不存在: ${id}`,
      metadata: { durationMs: 0 },
    };
  }
  if (!agentTool.enabled) {
    return {
      success: false,
      data: null,
      error: `工具已禁用: ${agentTool.slug}`,
      metadata: { durationMs: 0 },
    };
  }

  const executor = getExecutor(agentTool.type);
  if (!executor) {
    return {
      success: false,
      error: `工具类型未注册: ${agentTool.type}`,
      metadata: { durationMs: 0 },
    };
  }
  let config: unknown;
  try {
    config = JSON.parse(agentTool.config);
  } catch {
    config = agentTool.type === "fetch" ? DEFAULT_FETCH_CONFIG : {};
  }

  const ctx: ToolContext = {
    toolId: agentTool.id,
    toolSlug: agentTool.slug,
    userId,
  };

  const result = await executor.execute(input, config, ctx);

  // 写日志
  const status = result.success ? "success" : result.error?.includes("超时") ? "timeout" : "error";
  await writeToolLog({
    toolId: agentTool.id,
    toolSlug: agentTool.slug,
    userId,
    input: JSON.stringify(input),
    output: result.success ? JSON.stringify(result.data)?.slice(0, 10000) ?? null : null,
    status: status as "success" | "error" | "timeout",
    errorMessage: result.error ?? null,
    durationMs: result.metadata?.durationMs ?? 0,
  });

  return result;
}

export async function getEnabledToolsForLlm(): Promise<Record<string, ReturnType<typeof tool>>> {
  const tools = await dbGlobal
    .select()
    .from(agentTools)
    .where(eq(agentTools.enabled, 1))
    .orderBy(asc(agentTools.sortOrder));

  const result: Record<string, any> = {};
  for (const agentTool of tools) {
    const executor = getExecutor(agentTool.type);
    if (!executor) continue;
    let config: unknown;
    try {
      config = JSON.parse(agentTool.config);
    } catch {
      config = agentTool.type === "fetch" ? DEFAULT_FETCH_CONFIG : {};
    }

    const zodSchema = agentTool.type === "fetch" ? FETCH_INPUT_SCHEMA : z.object({});
    const jsonSch = z.toJSONSchema(zodSchema) as Record<string, unknown>;

    result[agentTool.slug] = tool({
      description: executor.buildDescription(config),
      parameters: jsonSchema(jsonSch, {
        validate: (v: unknown) => {
          const r = zodSchema.safeParse(v);
          return r.success
            ? { success: true as const, value: r.data }
            : { success: false as const, error: r.error };
        },
      }),
      execute: async (input: unknown) => {
        const execResult = await executeAgentTool(agentTool.id, input, null);
        if (!execResult.success) {
          return `工具执行失败: ${execResult.error ?? "未知错误"}。请停止调用此工具，基于已有信息回答用户或告知用户此工具不可用。`;
        }
        // 成功时返回内容，附带元信息帮助模型判断结果是否有效
        const meta = execResult.metadata;
        const sizeInfo = meta?.responseSize ? `${meta.responseSize} bytes` : `未知大小`;
        const statusInfo = meta?.statusCode ? `HTTP ${meta.statusCode}` : "";
        const dataStr = typeof execResult.data === "string" ? execResult.data : JSON.stringify(execResult.data);
        return `[fetch 结果 ${statusInfo} ${sizeInfo}]\n${dataStr}`;
      },
    });
  }
  return result;
}

export { DEFAULT_FETCH_CONFIG } from "./executors/fetch/config";
export type { FetchToolConfig } from "./executors/fetch/config";
export type { ToolExecutor, ToolContext, ToolResult } from "./registry";