import { z } from "zod";
import { createHash, randomBytes } from "node:crypto";
import type { JSONSchema7 } from "json-schema";
import type { ToolExecutor, ToolContext, ToolResult } from "../../registry";
import type { Base64ToolConfig } from "./config";

export const base64InputSchema = z.object({
  operation: z
    .enum([
      "base64-encode",
      "base64-decode",
      "base64url-encode",
      "base64url-decode",
      "url-encode",
      "url-decode",
      "hash",
    ])
    .describe("操作类型"),
  input: z.string().describe("输入内容"),
  algorithm: z
    .enum(["md5", "sha1", "sha256", "sha384", "sha512"])
    .optional()
    .describe("哈希算法 (hash 操作使用)"),
  encoding: z
    .enum(["hex", "base64"])
    .optional()
    .describe("哈希输出编码 (hash 操作使用)"),
});

type Base64Input = z.infer<typeof base64InputSchema>;

export const base64Executor: ToolExecutor<Base64ToolConfig> = {
  buildInputSchema(_config: Base64ToolConfig): JSONSchema7 {
    return {
      type: "object",
      properties: {
        operation: {
          type: "string",
          enum: [
            "base64-encode",
            "base64-decode",
            "base64url-encode",
            "base64url-decode",
            "url-encode",
            "url-decode",
            "hash",
          ],
          description: "操作类型",
        },
        input: { type: "string", description: "输入内容" },
        algorithm: {
          type: "string",
          enum: ["md5", "sha1", "sha256", "sha384", "sha512"],
          description: "哈希算法 (hash 操作)",
        },
        encoding: {
          type: "string",
          enum: ["hex", "base64"],
          description: "哈希输出编码",
        },
      },
      required: ["operation", "input"],
    };
  },

  buildDescription(config: Base64ToolConfig): string {
    return `编解码工具。支持 Base64/Base64URL 编解码、URL 编解码、哈希计算(md5/sha1/sha256/sha384/sha512)。最大输入 ${config.maxInputLength} 字符。`;
  },

  async execute(
    input: unknown,
    config: Base64ToolConfig,
    _ctx: ToolContext,
  ): Promise<ToolResult> {
    const start = Date.now();

    const parsed = base64InputSchema.safeParse(input);
    if (!parsed.success) {
      return {
        success: false,
        data: null,
        error: `输入参数校验失败: ${parsed.error.message}`,
        metadata: { durationMs: Date.now() - start },
      };
    }

    const inp = parsed.data as Base64Input;

    if (inp.input.length > config.maxInputLength) {
      return {
        success: false,
        data: null,
        error: `输入过长: ${inp.input.length} 字符 (限制 ${config.maxInputLength})`,
        metadata: { durationMs: Date.now() - start },
      };
    }

    try {
      let result: string;

      switch (inp.operation) {
        case "base64-encode":
          result = Buffer.from(inp.input, "utf-8").toString("base64");
          break;

        case "base64-decode":
          result = Buffer.from(inp.input, "base64").toString("utf-8");
          break;

        case "base64url-encode":
          result = Buffer.from(inp.input, "utf-8").toString("base64url");
          break;

        case "base64url-decode":
          result = Buffer.from(inp.input, "base64url").toString("utf-8");
          break;

        case "url-encode":
          result = encodeURIComponent(inp.input);
          break;

        case "url-decode":
          result = decodeURIComponent(inp.input);
          break;

        case "hash": {
          const algorithm = inp.algorithm ?? "sha256";
          const encoding = inp.encoding ?? "hex";
          const hash = createHash(algorithm).update(inp.input, "utf-8");
          result = hash.digest(encoding);
          break;
        }

        default:
          throw new Error(`未知操作: ${inp.operation}`);
      }

      return {
        success: true,
        data: {
          operation: inp.operation,
          input: inp.input,
          output: result,
          inputLength: inp.input.length,
          outputLength: result.length,
        },
        metadata: { durationMs: Date.now() - start },
      };
    } catch (e) {
      return {
        success: false,
        data: null,
        error: e instanceof Error ? e.message : String(e),
        metadata: { durationMs: Date.now() - start },
      };
    }
  },
};