import { hash } from "ohash";
import { handleCacheHeaders, defineEventHandler, createEvent } from "h3";
import { parseURL } from "ufo";
import { useStorage } from "#internal/nitro";
const defaultCacheOptions = {
  name: "_",
  base: "/cache",
  swr: true,
  maxAge: 1
};
export function defineCachedFunction(fn, opts) {
  opts = { ...defaultCacheOptions, ...opts };
  const pending = {};
  const group = opts.group || "nitro";
  const name = opts.name || fn.name || "_";
  const integrity = hash([opts.integrity, fn, opts]);
  const validate = opts.validate || (() => true);
  async function get(key, resolver) {
    const cacheKey = [opts.base, group, name, key + ".json"].filter(Boolean).join(":").replace(/:\/$/, ":index");
    const entry = await useStorage().getItem(cacheKey) || {};
    const ttl = (opts.maxAge ?? opts.maxAge ?? 0) * 1e3;
    if (ttl) {
      entry.expires = Date.now() + ttl;
    }
    const expired = entry.integrity !== integrity || ttl && Date.now() - (entry.mtime || 0) > ttl || !validate(entry);
    const _resolve = async () => {
      if (!pending[key]) {
        entry.value = void 0;
        entry.integrity = void 0;
        entry.mtime = void 0;
        entry.expires = void 0;
        pending[key] = Promise.resolve(resolver());
      }
      entry.value = await pending[key];
      entry.mtime = Date.now();
      entry.integrity = integrity;
      delete pending[key];
      if (validate(entry)) {
        useStorage().setItem(cacheKey, entry).catch((error) => console.error("[nitro] [cache]", error));
      }
    };
    const _resolvePromise = expired ? _resolve() : Promise.resolve();
    if (opts.swr && entry.value) {
      _resolvePromise.catch(console.error);
      return Promise.resolve(entry);
    }
    return _resolvePromise.then(() => entry);
  }
  return async (...args) => {
    const key = (opts.getKey || getKey)(...args);
    const entry = await get(key, () => fn(...args));
    let value = entry.value;
    if (opts.transform) {
      value = await opts.transform(entry, ...args) || value;
    }
    return value;
  };
}
export const cachedFunction = defineCachedFunction;
function getKey(...args) {
  return args.length ? hash(args, {}) : "";
}
export function defineCachedEventHandler(handler, opts = defaultCacheOptions) {
  const _opts = {
    ...opts,
    getKey: (event) => {
      const url = event.req.originalUrl || event.req.url;
      const friendlyName = decodeURI(parseURL(url).pathname).replace(/[^a-zA-Z0-9]/g, "").substring(0, 16);
      const urlHash = hash(url);
      return `${friendlyName}.${urlHash}`;
    },
    validate: (entry) => {
      if (entry.value.code >= 400) {
        return false;
      }
      if (entry.value.body === void 0) {
        return false;
      }
      return true;
    },
    group: opts.group || "nitro/handlers",
    integrity: [
      opts.integrity,
      handler
    ]
  };
  const _cachedHandler = cachedFunction(async (incomingEvent) => {
    const reqProxy = cloneWithProxy(incomingEvent.req, { headers: {} });
    const resHeaders = {};
    let _resSendBody;
    const resProxy = cloneWithProxy(incomingEvent.res, {
      statusCode: 200,
      getHeader(name) {
        return resHeaders[name];
      },
      setHeader(name, value) {
        resHeaders[name] = value;
        return this;
      },
      getHeaderNames() {
        return Object.keys(resHeaders);
      },
      hasHeader(name) {
        return name in resHeaders;
      },
      removeHeader(name) {
        delete resHeaders[name];
      },
      getHeaders() {
        return resHeaders;
      },
      end(chunk, arg2, arg3) {
        if (typeof chunk === "string") {
          _resSendBody = chunk;
        }
        if (typeof arg2 === "function") {
          arg2();
        }
        if (typeof arg3 === "function") {
          arg3();
        }
        return this;
      },
      write(chunk, arg2, arg3) {
        if (typeof chunk === "string") {
          _resSendBody = chunk;
        }
        if (typeof arg2 === "function") {
          arg2();
        }
        if (typeof arg3 === "function") {
          arg3();
        }
        return this;
      },
      writeHead(statusCode, headers2) {
        this.statusCode = statusCode;
        if (headers2) {
          for (const header in headers2) {
            this.setHeader(header, headers2[header]);
          }
        }
        return this;
      }
    });
    const event = createEvent(reqProxy, resProxy);
    event.context = incomingEvent.context;
    const body = await handler(event) || _resSendBody;
    const headers = event.res.getHeaders();
    headers.etag = headers.Etag || headers.etag || `W/"${hash(body)}"`;
    headers["last-modified"] = headers["Last-Modified"] || headers["last-modified"] || new Date().toUTCString();
    const cacheControl = [];
    if (opts.swr) {
      if (opts.maxAge) {
        cacheControl.push(`s-maxage=${opts.maxAge}`);
      }
      if (opts.staleMaxAge) {
        cacheControl.push(`stale-while-revalidate=${opts.staleMaxAge}`);
      } else {
        cacheControl.push("stale-while-revalidate");
      }
    } else if (opts.maxAge) {
      cacheControl.push(`max-age=${opts.maxAge}`);
    }
    if (cacheControl.length) {
      headers["cache-control"] = cacheControl.join(", ");
    }
    const cacheEntry = {
      code: event.res.statusCode,
      headers,
      body
    };
    return cacheEntry;
  }, _opts);
  return defineEventHandler(async (event) => {
    if (opts.headersOnly) {
      if (handleCacheHeaders(event, { maxAge: opts.maxAge })) {
        return;
      }
      return handler(event);
    }
    const response = await _cachedHandler(event);
    if (event.res.headersSent || event.res.writableEnded) {
      return response.body;
    }
    if (handleCacheHeaders(event, {
      modifiedTime: new Date(response.headers["last-modified"]),
      etag: response.headers.etag,
      maxAge: opts.maxAge
    })) {
      return;
    }
    event.res.statusCode = response.code;
    for (const name in response.headers) {
      event.res.setHeader(name, response.headers[name]);
    }
    return response.body;
  });
}
function cloneWithProxy(obj, overrides) {
  return new Proxy(obj, {
    get(target, property, receiver) {
      if (property in overrides) {
        return overrides[property];
      }
      return Reflect.get(target, property, receiver);
    },
    set(target, property, value, receiver) {
      if (property in overrides) {
        overrides[property] = value;
        return true;
      }
      return Reflect.set(target, property, value, receiver);
    }
  });
}
export const cachedEventHandler = defineCachedEventHandler;