import { beforeEach, describe, expect, it } from "vitest";
import type { ComposerDraftStorage } from "./composer-drafts.js";
import {
  COMPOSER_DRAFT_LIMIT,
  COMPOSER_DRAFT_STORAGE_KEY,
  clearComposerDraft,
  composerDraftThreadKey,
  EMPTY_COMPOSER_DRAFT,
  isComposerDraftEmpty,
  readComposerDraft,
  resetMemoryComposerDrafts,
  writeComposerDraft,
} from "./composer-drafts.js";

function createFakeStorage(): ComposerDraftStorage & { map: Map<string, string> } {
  const map = new Map<string, string>();
  return {
    map,
    getItem(key: string) {
      return map.get(key) ?? null;
    },
    setItem(key: string, value: string) {
      map.set(key, value);
    },
    removeItem(key: string) {
      map.delete(key);
    },
  };
}

describe("composer-drafts", () => {
  beforeEach(() => {
    resetMemoryComposerDrafts();
  });

  it("derives thread keys for bot and group conversations", () => {
    expect(composerDraftThreadKey({ botId: "bot-1" })).toBe("bot:bot-1");
    expect(composerDraftThreadKey({ groupId: "grp-1", botId: "bot-1" })).toBe("group:grp-1");
    expect(composerDraftThreadKey({ botId: "  ", groupId: null })).toBeUndefined();
  });

  it("detects empty vs non-empty drafts", () => {
    expect(isComposerDraftEmpty(EMPTY_COMPOSER_DRAFT)).toBe(true);
    expect(
      isComposerDraftEmpty({
        text: "Weiter an der Aufgabe schreiben",
        selectedSkill: null,
        selectedMentions: [],
      }),
    ).toBe(false);
    expect(
      isComposerDraftEmpty({
        text: "",
        selectedSkill: {
          id: "skill-1",
          name: "research",
          description: "Research skill",
          source: "user",
          readOnly: false,
        },
        selectedMentions: [],
      }),
    ).toBe(false);
  });

  it("persists and restores drafts across thread and page switches independently", () => {
    const storage = createFakeStorage();
    const botKey = composerDraftThreadKey({ botId: "alpha" });
    const groupKey = composerDraftThreadKey({ groupId: "team-room" });

    writeComposerDraft(
      botKey,
      {
        text: "Entwurf im ersten Chat",
        selectedSkill: {
          id: "sk-1",
          name: "summarize",
          description: "Summarize notes",
          source: "builtin",
          readOnly: true,
        },
        selectedMentions: [
          {
            kind: "bot",
            id: "helper-bot",
            name: "Helper",
            color: "#112233",
          },
        ],
      },
      storage,
    );

    writeComposerDraft(
      groupKey,
      {
        text: "Andere Nachricht in der Gruppe",
        selectedSkill: null,
        selectedMentions: [],
      },
      storage,
    );

    expect(readComposerDraft(botKey, storage)).toEqual({
      text: "Entwurf im ersten Chat",
      selectedSkill: {
        id: "sk-1",
        name: "summarize",
        description: "Summarize notes",
        source: "builtin",
        readOnly: true,
      },
      selectedMentions: [
        {
          kind: "bot",
          id: "helper-bot",
          name: "Helper",
          color: "#112233",
        },
      ],
    });
    expect(readComposerDraft(groupKey, storage)).toEqual({
      text: "Andere Nachricht in der Gruppe",
      selectedSkill: null,
      selectedMentions: [],
    });

    clearComposerDraft(botKey, storage);
    expect(readComposerDraft(botKey, storage)).toEqual(EMPTY_COMPOSER_DRAFT);
    expect(readComposerDraft(groupKey, storage).text).toBe("Andere Nachricht in der Gruppe");

    clearComposerDraft(groupKey, storage);
    expect(storage.map.has(COMPOSER_DRAFT_STORAGE_KEY)).toBe(false);
  });

  it("evicts oldest drafts beyond COMPOSER_DRAFT_LIMIT", () => {
    const storage = createFakeStorage();
    for (let index = 0; index < COMPOSER_DRAFT_LIMIT + 5; index += 1) {
      writeComposerDraft(
        `bot:b-${index}`,
        {
          text: `Draft ${index}`,
          selectedSkill: null,
          selectedMentions: [],
        },
        storage,
      );
    }

    expect(readComposerDraft("bot:b-0", storage)).toEqual(EMPTY_COMPOSER_DRAFT);
    expect(readComposerDraft("bot:b-4", storage)).toEqual(EMPTY_COMPOSER_DRAFT);
    expect(readComposerDraft("bot:b-5", storage).text).toBe("Draft 5");
    expect(readComposerDraft(`bot:b-${COMPOSER_DRAFT_LIMIT + 4}`, storage).text).toBe(
      `Draft ${COMPOSER_DRAFT_LIMIT + 4}`,
    );
  });

  it("falls back to in-memory storage when persistent storage is unavailable", () => {
    const key = composerDraftThreadKey({ botId: "mobile-bot" });
    writeComposerDraft(
      key,
      {
        text: "Mobile Entwurf bleibt beim Tab-Wechsel erhalten",
        selectedSkill: null,
        selectedMentions: [],
      },
      null,
    );

    expect(readComposerDraft(key, null).text).toBe(
      "Mobile Entwurf bleibt beim Tab-Wechsel erhalten",
    );
    clearComposerDraft(key, null);
    expect(readComposerDraft(key, null)).toEqual(EMPTY_COMPOSER_DRAFT);
  });
});