import type {
  Completion,
  CompletionContext,
  CompletionResult,
  CompletionSource,
} from "@codemirror/autocomplete"
import type { EditorView } from "@codemirror/view"
import { LANGUAGE } from "utils/types"
import { c } from "./c"
import { python } from "./python"

type ChineseCompletion = Pick<
  Completion,
  "label" | "detail" | "type" | "info" | "boost" | "apply"
> & { apply?: string | Completion["apply"] }

// 中文注释提示
const chineseAnnotations: Record<string, ChineseCompletion[]> = {
  python,
  c,
}

export function enhanceCompletion(language: LANGUAGE): CompletionSource {
  return async function (
    context: CompletionContext,
  ): Promise<CompletionResult | null> {
    const word = context.matchBefore(/\w+/)
    if (!word) return null

    const trulyLanguage = language.startsWith("Python") ? "python" : "c"
    const completions: Completion[] = (
      chineseAnnotations[trulyLanguage] || []
    ).map((completion) => {
      const insertText =
        typeof completion.apply === "string"
          ? completion.apply
          : completion.label
      const cursorOffset = insertText.includes("(")
        ? insertText.indexOf("(") + 1
        : insertText.length

      if (
        (completion.type === "function" || completion.type === "method") &&
        insertText.includes(")")
      ) {
        return {
          ...completion,
          apply: (
            view: EditorView,
            _c: Completion,
            from: number,
            to: number,
          ) => {
            view.dispatch({
              changes: { from, to, insert: insertText },
              selection: { anchor: from + cursorOffset },
            })
          },
        }
      }

      return completion
    })

    return {
      from: word.from,
      options: completions,
      validFor: /^\w+$/,
    }
  }
}