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import { Context } from './context.ts'import type { ParamIndexMap, Params } from './router.ts'import type { Env, NotFoundHandler, ErrorHandler } from './types.ts'
interface ComposeContext {  finalized: boolean  res: unknown}
// Based on the code in the MIT licensed `koa-compose` package.export const compose = <C extends ComposeContext, E extends Env = Env>(  middleware: [[Function, unknown], ParamIndexMap | Params][],  onError?: ErrorHandler<E>,  onNotFound?: NotFoundHandler<E>) => {  return (context: C, next?: Function) => {    let index = -1    return dispatch(0)
    async function dispatch(i: number): Promise<C> {      if (i <= index) {        throw new Error('next() called multiple times')      }      index = i
      let res      let isError = false      let handler
      if (middleware[i]) {        handler = middleware[i][0][0]        if (context instanceof Context) {          context.req.routeIndex = i        }      } else {        handler = (i === middleware.length && next) || undefined      }
      if (!handler) {        if (context instanceof Context && context.finalized === false && onNotFound) {          res = await onNotFound(context)        }      } else {        try {          res = await handler(context, () => {            return dispatch(i + 1)          })        } catch (err) {          if (err instanceof Error && context instanceof Context && onError) {            context.error = err            res = await onError(err, context)            isError = true          } else {            throw err          }        }      }
      if (res && (context.finalized === false || isError)) {        context.res = res      }      return context    }  }}