/* The driver conformance suite, written once and pointed at a driver.

   CI runs it against the sqlite-wasm driver in Node. The same export can be
   pointed at the Capacitor driver on a device — that is what "same schema,
   same queries, same migrations on both" has to mean in practice. */

import { describe, it, expect, beforeEach, afterEach } from "vitest";
import type { Db } from "@app/db/types.js";
import { migrate } from "@app/db/migrate.js";
import { SCHEMA_VERSION } from "@app/db/migrations.js";
import {
  seedCard,
  seedChatTurn,
  seedMeta,
  seedProgress,
  editCard,
  editMeta,
  editPeek,
  editStudyLog,
  editUnitConfidence,
  insertBand,
} from "@app/db/writes.js";
import { newCard, grade, GOOD } from "@lib/srs.js";

/** Every table that carries user data, and therefore a write timestamp. */
const SYNCABLE = ["card", "progress", "chat", "meta", "study_log", "peek", "custom_word"] as const;

export function conformanceSuite(name: string, open: () => Promise<Db>): void {
  describe(`Db conformance — ${name}`, () => {
    let db: Db;

    beforeEach(async () => {
      db = await open();
      await migrate(db);
    });
    afterEach(async () => {
      await db.close();
    });

    describe("migrations", () => {
      it("reaches the current schema version", async () => {
        const row = await db.get<{ v: string }>("SELECT v FROM meta WHERE k='schema_version'");
        expect(row?.v).toBe(String(SCHEMA_VERSION));
      });

      it("creates every table the app expects", async () => {
        const rows = await db.all<{ name: string }>(
          "SELECT name FROM sqlite_master WHERE type='table'",
        );
        const names = new Set(rows.map((r) => r.name));
        for (const t of ["lemma", "surface", ...SYNCABLE]) expect(names.has(t), t).toBe(true);
      });

      it("is idempotent — running it again changes nothing", async () => {
        const again = await migrate(db);
        expect(again.from).toBe(SCHEMA_VERSION);
        expect(again.to).toBe(SCHEMA_VERSION);
      });
    });

    describe("queries", () => {
      it("round-trips every value type", async () => {
        await db.run("INSERT INTO lemma (id, headword, pos, freq_rank, gloss_en, source) VALUES (?,?,?,?,?,?)", [
          1,
          "밥",
          "noun",
          null,
          "rice",
          "curated",
        ]);
        const row = await db.get<{ headword: string; freq_rank: number | null }>(
          "SELECT headword, freq_rank FROM lemma WHERE id = ?",
          [1],
        );
        expect(row).toEqual({ headword: "밥", freq_rank: null });
      });

      it("get() returns undefined when nothing matches", async () => {
        expect(await db.get("SELECT 1 AS x WHERE 0")).toBeUndefined();
      });

      it("all() returns every row, in order", async () => {
        await db.exec(`
          INSERT INTO lemma (id, headword, pos, freq_rank, gloss_en, source) VALUES
            (1,'가','verb',10,'go','curated'),
            (2,'나','pron',20,'I','curated'),
            (3,'다','adv',30,'all','curated');
        `);
        const rows = await db.all<{ headword: string }>(
          "SELECT headword FROM lemma ORDER BY freq_rank",
        );
        expect(rows.map((r) => r.headword)).toEqual(["가", "나", "다"]);
      });
    });

    describe("transactions", () => {
      it("commits on success", async () => {
        await db.tx(async (tx) => {
          await tx.run("INSERT INTO meta (k, v) VALUES ('a', '1')");
          await tx.run("INSERT INTO meta (k, v) VALUES ('b', '2')");
        });
        const rows = await db.all("SELECT k FROM meta WHERE k IN ('a','b')");
        expect(rows).toHaveLength(2);
      });

      it("rolls back everything when the callback throws", async () => {
        await expect(
          db.tx(async (tx) => {
            await tx.run("INSERT INTO meta (k, v) VALUES ('c', '3')");
            throw new Error("boom");
          }),
        ).rejects.toThrow("boom");
        expect(await db.get("SELECT k FROM meta WHERE k='c'")).toBeUndefined();
      });

      it("sees its own writes inside the transaction", async () => {
        const seen = await db.tx(async (tx) => {
          await tx.run("INSERT INTO meta (k, v) VALUES ('d', '4')");
          return tx.get<{ v: string }>("SELECT v FROM meta WHERE k='d'");
        });
        expect(seen?.v).toBe("4");
      });

      it("survives a rollback and keeps working", async () => {
        await db.tx(async (tx) => tx.run("INSERT INTO meta (k,v) VALUES ('e','5')")).catch(() => {});
        await expect(
          db.tx(async (tx) => {
            await tx.run("INSERT INTO meta (k,v) VALUES ('f','6')");
            throw new Error("x");
          }),
        ).rejects.toThrow();
        await db.run("INSERT INTO meta (k, v) VALUES ('g', '7')");
        expect((await db.get<{ v: string }>("SELECT v FROM meta WHERE k='g'"))?.v).toBe("7");
      });
    });

    describe("bulk band insert", () => {
      it("loads lemma and surface rows together", async () => {
        await insertBand(
          db,
          [
            {
              id: 100,
              headword: "먹다",
              pos: "verb",
              freq_rank: 42,
              level: "초급",
              gloss_en: "to eat",
              gloss_ko: "",
              unit_band: 1,
              source: "curated",
            },
          ],
          [
            { form: "먹어", lemma_id: 100, analysis: "반말, from 먹다" },
            { form: "먹었어", lemma_id: 100, analysis: "반말 past, from 먹다" },
          ],
        );
        const hit = await db.get<{ headword: string; analysis: string }>(
          `SELECT l.headword, s.analysis FROM surface s
             JOIN lemma l ON l.id = s.lemma_id WHERE s.form = ?`,
          ["먹었어"],
        );
        expect(hit?.headword).toBe("먹다");
        expect(hit?.analysis).toContain("past");
      });

      it("is re-runnable — reloading a band does not duplicate", async () => {
        const lemma = {
          id: 200,
          headword: "물",
          pos: "noun",
          freq_rank: 7,
          level: null,
          gloss_en: "water",
          gloss_ko: "",
          unit_band: 0,
          source: "curated",
        };
        await insertBand(db, [lemma], [{ form: "물", lemma_id: 200, analysis: "headword" }]);
        await insertBand(db, [lemma], [{ form: "물", lemma_id: 200, analysis: "headword" }]);
        const n = await db.get<{ n: number }>("SELECT count(*) AS n FROM lemma WHERE id = 200");
        expect(n?.n).toBe(1);
      });
    });

    /* ═══════════════════════════════════════════════════════════════
       The trap. A fresh device must never claim its empty defaults are
       newer than the server's real history.
       ═══════════════════════════════════════════════════════════════ */
    describe("seeded state carries no write timestamp", () => {
      it("leaves updated_at at 0 across every syncable table after a full seed", async () => {
        await seedProgress(db, "1.1");
        await seedMeta(db, "focus", "auto");
        await seedMeta(db, "prefs.newPerDay", "10");
        await db.run(
          "INSERT INTO lemma (id, headword, pos, gloss_en, source) VALUES (1,'밥','noun','rice','curated')",
        );
        await seedCard(db, 1, newCard());
        await seedChatTurn(db, "assistant", "안녕! 시작하자.", 0);

        for (const table of SYNCABLE) {
          const row = await db.get<{ n: number }>(
            `SELECT count(*) AS n FROM ${table} WHERE updated_at != 0`,
          );
          expect(row?.n, `${table} has a stamped seed row`).toBe(0);
        }
      });

      it("still writes 0 when the migration itself records the schema version", async () => {
        const row = await db.get<{ updated_at: number }>(
          "SELECT updated_at FROM meta WHERE k='schema_version'",
        );
        expect(row?.updated_at).toBe(0);
      });

      it("but a genuine edit does stamp the clock", async () => {
        await db.run(
          "INSERT INTO lemma (id, headword, pos, gloss_en, source) VALUES (2,'물','noun','water','curated')",
        );
        const before = Date.now();
        await editCard(db, 2, grade(newCard(), GOOD, 20_000));
        await editUnitConfidence(db, "1.1", 40);
        await editMeta(db, "prefs.newPerDay", "20");
        await editStudyLog(db, 20_000, { reviews: 1, correct: 1 });
        await editPeek(db, "물");

        for (const [table, where] of [
          ["card", "lemma_id = 2"],
          ["progress", "unit_id = '1.1'"],
          ["meta", "k = 'prefs.newPerDay'"],
          ["study_log", "day = 20000"],
          ["peek", "form = '물'"],
        ] as const) {
          const row = await db.get<{ updated_at: number }>(
            `SELECT updated_at FROM ${table} WHERE ${where}`,
          );
          expect(row?.updated_at, `${table} was not stamped`).toBeGreaterThanOrEqual(before);
        }
      });

      it("an edit on top of a seeded row promotes it from 0", async () => {
        await seedProgress(db, "2.1");
        const seeded = await db.get<{ updated_at: number }>(
          "SELECT updated_at FROM progress WHERE unit_id='2.1'",
        );
        expect(seeded?.updated_at).toBe(0);

        await editUnitConfidence(db, "2.1", 55);
        const edited = await db.get<{ updated_at: number; confidence: number }>(
          "SELECT updated_at, confidence FROM progress WHERE unit_id='2.1'",
        );
        expect(edited?.confidence).toBe(55);
        expect(edited?.updated_at).toBeGreaterThan(0);
      });

      it("seeding never overwrites a real edit", async () => {
        await editUnitConfidence(db, "3.1", 90);
        await seedProgress(db, "3.1"); // first-run path running again
        const row = await db.get<{ confidence: number; updated_at: number }>(
          "SELECT confidence, updated_at FROM progress WHERE unit_id='3.1'",
        );
        expect(row?.confidence).toBe(90);
        expect(row?.updated_at).toBeGreaterThan(0);
      });
    });
  });
}