import {
  createEvent,
  defineEventHandler,
  fetchWithEvent,
  handleCacheHeaders,
  isEvent,
  splitCookiesString
} from "h3";
import { parseURL } from "ufo";
import { useNitroApp } from "./app.mjs";
import { useStorage } from "./storage.mjs";
import { hash } from "./hash.mjs";
function defaultCacheOptions() {
  return {
    name: "_",
    base: "/cache",
    swr: true,
    maxAge: 1
  };
}
export function defineCachedFunction(fn, opts = {}) {
  opts = { ...defaultCacheOptions(), ...opts };
  const pending = {};
  const group = opts.group || "nitro/functions";
  const name = opts.name || fn.name || "_";
  const integrity = opts.integrity || hash([fn, opts]);
  const validate = opts.validate || ((entry) => entry.value !== void 0);
  async function get(key, resolver, shouldInvalidateCache, event) {
    const cacheKey = [opts.base, group, name, key + ".json"].filter(Boolean).join(":").replace(/:\/$/, ":index");
    let entry = await useStorage().getItem(cacheKey).catch((error) => {
      console.error(`[cache] Cache read error.`, error);
      useNitroApp().captureError(error, { event, tags: ["cache"] });
    }) || {};
    if (typeof entry !== "object") {
      entry = {};
      const error = new Error("Malformed data read from cache.");
      console.error("[cache]", error);
      useNitroApp().captureError(error, { event, tags: ["cache"] });
    }
    const ttl = (opts.maxAge ?? 0) * 1e3;
    if (ttl) {
      entry.expires = Date.now() + ttl;
    }
    const expired = shouldInvalidateCache || entry.integrity !== integrity || ttl && Date.now() - (entry.mtime || 0) > ttl || validate(entry) === false;
    const _resolve = async () => {
      const isPending = pending[key];
      if (!isPending) {
        if (entry.value !== void 0 && (opts.staleMaxAge || 0) >= 0 && opts.swr === false) {
          entry.value = void 0;
          entry.integrity = void 0;
          entry.mtime = void 0;
          entry.expires = void 0;
        }
        pending[key] = Promise.resolve(resolver());
      }
      try {
        entry.value = await pending[key];
      } catch (error) {
        if (!isPending) {
          delete pending[key];
        }
        throw error;
      }
      if (!isPending) {
        entry.mtime = Date.now();
        entry.integrity = integrity;
        delete pending[key];
        if (validate(entry) !== false) {
          let setOpts;
          if (opts.maxAge && !opts.swr) {
            setOpts = { ttl: opts.maxAge };
          }
          const promise = useStorage().setItem(cacheKey, entry, setOpts).catch((error) => {
            console.error(`[cache] Cache write error.`, error);
            useNitroApp().captureError(error, { event, tags: ["cache"] });
          });
          if (event?.waitUntil) {
            event.waitUntil(promise);
          }
        }
      }
    };
    const _resolvePromise = expired ? _resolve() : Promise.resolve();
    if (entry.value === void 0) {
      await _resolvePromise;
    } else if (expired && event && event.waitUntil) {
      event.waitUntil(_resolvePromise);
    }
    if (opts.swr && validate(entry) !== false) {
      _resolvePromise.catch((error) => {
        console.error(`[cache] SWR handler error.`, error);
        useNitroApp().captureError(error, { event, tags: ["cache"] });
      });
      return entry;
    }
    return _resolvePromise.then(() => entry);
  }
  return async (...args) => {
    const shouldBypassCache = await opts.shouldBypassCache?.(...args);
    if (shouldBypassCache) {
      return fn(...args);
    }
    const key = await (opts.getKey || getKey)(...args);
    const shouldInvalidateCache = await opts.shouldInvalidateCache?.(...args);
    const entry = await get(
      key,
      () => fn(...args),
      shouldInvalidateCache,
      args[0] && isEvent(args[0]) ? args[0] : void 0
    );
    let value = entry.value;
    if (opts.transform) {
      value = await opts.transform(entry, ...args) || value;
    }
    return value;
  };
}
export function cachedFunction(fn, opts = {}) {
  return defineCachedFunction(fn, opts);
}
function getKey(...args) {
  return args.length > 0 ? hash(args) : "";
}
function escapeKey(key) {
  return String(key).replace(/\W/g, "");
}
export function defineCachedEventHandler(handler, opts = defaultCacheOptions()) {
  const variableHeaderNames = (opts.varies || []).filter(Boolean).map((h) => h.toLowerCase()).sort();
  const _opts = {
    ...opts,
    getKey: async (event) => {
      const customKey = await opts.getKey?.(event);
      if (customKey) {
        return escapeKey(customKey);
      }
      const _path = event.node.req.originalUrl || event.node.req.url || event.path;
      let _pathname;
      try {
        _pathname = escapeKey(decodeURI(parseURL(_path).pathname)).slice(0, 16) || "index";
      } catch {
        _pathname = "-";
      }
      const _hashedPath = `${_pathname}.${hash(_path)}`;
      const _headers = variableHeaderNames.map((header) => [header, event.node.req.headers[header]]).map(([name, value]) => `${escapeKey(name)}.${hash(value)}`);
      return [_hashedPath, ..._headers].join(":");
    },
    validate: (entry) => {
      if (!entry.value) {
        return false;
      }
      if (entry.value.code >= 400) {
        return false;
      }
      if (entry.value.body === void 0) {
        return false;
      }
      if (entry.value.headers.etag === "undefined" || entry.value.headers["last-modified"] === "undefined") {
        return false;
      }
      return true;
    },
    group: opts.group || "nitro/handlers",
    integrity: opts.integrity || hash([handler, opts])
  };
  const _cachedHandler = cachedFunction(
    async (incomingEvent) => {
      const variableHeaders = {};
      for (const header of variableHeaderNames) {
        const value = incomingEvent.node.req.headers[header];
        if (value !== void 0) {
          variableHeaders[header] = value;
        }
      }
      const reqProxy = cloneWithProxy(incomingEvent.node.req, {
        headers: variableHeaders
      });
      const resHeaders = {};
      let _resSendBody;
      const resProxy = cloneWithProxy(incomingEvent.node.res, {
        statusCode: 200,
        writableEnded: false,
        writableFinished: false,
        headersSent: false,
        closed: false,
        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(void 0);
          }
          if (typeof arg3 === "function") {
            arg3();
          }
          return true;
        },
        writeHead(statusCode, headers2) {
          this.statusCode = statusCode;
          if (headers2) {
            if (Array.isArray(headers2) || typeof headers2 === "string") {
              throw new TypeError("Raw headers  is not supported.");
            }
            for (const header in headers2) {
              const value = headers2[header];
              if (value !== void 0) {
                this.setHeader(
                  header,
                  value
                );
              }
            }
          }
          return this;
        }
      });
      const event = createEvent(reqProxy, resProxy);
      event.fetch = (url, fetchOptions) => fetchWithEvent(event, url, fetchOptions, {
        fetch: useNitroApp().localFetch
      });
      event.$fetch = (url, fetchOptions) => fetchWithEvent(event, url, fetchOptions, {
        fetch: globalThis.$fetch
      });
      event.waitUntil = incomingEvent.waitUntil;
      event.context = incomingEvent.context;
      event.context.cache = {
        options: _opts
      };
      const body = await handler(event) || _resSendBody;
      const headers = event.node.res.getHeaders();
      headers.etag = String(
        headers.Etag || headers.etag || `W/"${hash(body)}"`
      );
      headers["last-modified"] = String(
        headers["Last-Modified"] || headers["last-modified"] || (/* @__PURE__ */ 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 > 0) {
        headers["cache-control"] = cacheControl.join(", ");
      }
      const cacheEntry = {
        code: event.node.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.node.res.headersSent || event.node.res.writableEnded) {
      return response.body;
    }
    if (handleCacheHeaders(event, {
      modifiedTime: new Date(response.headers["last-modified"]),
      etag: response.headers.etag,
      maxAge: opts.maxAge
    })) {
      return;
    }
    event.node.res.statusCode = response.code;
    for (const name in response.headers) {
      const value = response.headers[name];
      if (name === "set-cookie") {
        event.node.res.appendHeader(
          name,
          splitCookiesString(value)
        );
      } else {
        if (value !== void 0) {
          event.node.res.setHeader(name, value);
        }
      }
    }
    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;