import type { PromisifyAssertion, Tester } from '@vitest/expect'
import type { Plugin as PrettyFormatPlugin } from '@vitest/pretty-format'
import type { SnapshotState } from '@vitest/snapshot'
import type { BenchResult } from '../runtime/benchmark'
import type { Test } from '../runtime/runner/types'

interface SnapshotMatcher<T> {
  <U extends { [P in keyof T]: any }>(
    snapshot: Partial<U>,
    hint?: string
  ): void
  (hint?: string): void
}

interface InlineSnapshotMatcher<T> {
  <U extends { [P in keyof T]: any }>(
    properties: Partial<U>,
    snapshot?: string,
    hint?: string
  ): void
  (hint?: string): void
}

declare module 'vitest' {
  interface MatcherState {
    environment: string
    snapshotState: SnapshotState
    task?: Readonly<Test>
  }

  interface ExpectPollOptions {
    interval?: number
    timeout?: number
    message?: string
  }

  interface ExpectStatic {
    assert: Chai.AssertStatic
    unreachable: (message?: string) => never
    soft: <T>(actual: T, message?: string) => Assertion<T>
    poll: <T>(
      actual: (options: { signal: AbortSignal }) => T,
      options?: ExpectPollOptions,
    ) => PromisifyAssertion<Awaited<T>>
    addEqualityTesters: (testers: Array<Tester>) => void
    assertions: (expected: number) => void
    hasAssertions: () => void
    addSnapshotSerializer: (plugin: PrettyFormatPlugin) => void
  }

  interface Assertion<T> {
    // Snapshots are extended in @vitest/snapshot and are not part of @vitest/expect
    matchSnapshot: SnapshotMatcher<T>
    toMatchSnapshot: SnapshotMatcher<T>
    toMatchInlineSnapshot: InlineSnapshotMatcher<T>

    /**
     * Checks that an error thrown by a function matches a previously recorded snapshot.
     *
     * @param hint - Optional custom error message.
     *
     * @example
     * expect(functionWithError).toThrowErrorMatchingSnapshot();
     */
    toThrowErrorMatchingSnapshot: (hint?: string) => void

    /**
     * Checks that an error thrown by a function matches an inline snapshot within the test file.
     * Useful for keeping snapshots close to the test code.
     *
     * @param snapshot - Optional inline snapshot string to match.
     * @param hint - Optional custom error message.
     *
     * @example
     * const throwError = () => { throw new Error('Error occurred') };
     * expect(throwError).toThrowErrorMatchingInlineSnapshot(`"Error occurred"`);
     */
    toThrowErrorMatchingInlineSnapshot: (
      snapshot?: string,
      hint?: string,
    ) => void

    /**
     * Compares the received value to a snapshot saved in a specified file.
     * Useful for cases where snapshot content is large or needs to be shared across tests.
     *
     * @param filepath - Path to the snapshot file.
     * @param hint - Optional custom error message.
     *
     * @example
     * await expect(largeData).toMatchFileSnapshot('path/to/snapshot.json');
     */
    toMatchFileSnapshot: (filepath: string, hint?: string) => Promise<void>

    /**
     * Asserts that a benchmark result is faster than another benchmark result.
     * Compares mean latency — lower is faster.
     *
     * @example
     * const result = await bench.compare(
     *   bench('lib1', () => { lib1() }),
     *   bench('lib2', () => { lib2() }),
     * )
     * expect(result.get('lib1')).toBeFasterThan(result.get('lib2'))
     * expect(result.get('lib1')).toBeFasterThan(result.get('lib2'), { delta: 0.1 })
     */
    toBeFasterThan: (
      expected: BenchResult,
      options?: { delta?: number },
    ) => void

    /**
     * Asserts that a benchmark result is slower than another benchmark result.
     * Compares mean latency — higher is slower.
     *
     * @example
     * const result = await bench.compare(
     *   bench('lib1', () => { lib1() }),
     *   bench('lib2', () => { lib2() }),
     * )
     * expect(result.get('lib2')).toBeSlowerThan(result.get('lib1'))
     * expect(result.get('lib2')).toBeSlowerThan(result.get('lib1'), { delta: 0.2 })
     */
    toBeSlowerThan: (
      expected: BenchResult,
      options?: { delta?: number },
    ) => void
  }
}
