import { appendFileSync } from "node:fs";
import { join } from "node:path";
import { describe, expect, it } from "vitest";
import { UsageLedger, type BeginUsage } from "../src/billing/ledger.js";
import { silentLogger, tempRoot } from "./helpers.js";

function usage(overrides: Partial<BeginUsage> = {}): BeginUsage {
  return {
    uid: "1",
    team_id: "1",
    session_id: "s1",
    tool_call_id: "call-1",
    skill_id: "demo",
    skill_name: "Demo",
    model: "seedream@5.0",
    size: "1024x1536",
    quantity: 2,
    unit_credits: 30,
    size_multiplier: 1,
    total_credits: 60,
    currency: "credits",
    billing_mode: "dry_run",
    ...overrides,
  };
}

describe("UsageLedger", () => {
  it("records pending and succeeded usage and finds it by tool call", () => {
    const ledger = new UsageLedger(join(tempRoot(), "ledger.jsonl"), silentLogger);
    const record = ledger.begin(usage());
    expect(record.status).toBe("pending");

    ledger.settle(record.id, "succeeded", {
      gateway_task_id: "task-1",
      image_urls: ["https://img/1.png", "https://img/2.png"],
    });

    const found = ledger.findSucceededToolCall("1", "s1", "call-1");
    expect(found?.id).toBe(record.id);
    expect(found?.status).toBe("succeeded");
    expect(found?.image_urls).toHaveLength(2);
    expect(ledger.findSucceededToolCall("2", "s1", "call-1")).toBeUndefined();
  });

  it("persists records and rebuilds the idempotency index", () => {
    const file = join(tempRoot(), "ledger.jsonl");
    const ledger = new UsageLedger(file, silentLogger);
    const record = ledger.begin(usage());
    ledger.settle(record.id, "succeeded", { image_urls: ["https://img/1.png"] });

    const reloaded = new UsageLedger(file, silentLogger);
    expect(reloaded.list()).toHaveLength(1);
    expect(reloaded.findSucceededToolCall("1", "s1", "call-1")?.id).toBe(record.id);
  });

  it("does not index failed calls and summarises by status and skill", () => {
    const ledger = new UsageLedger(join(tempRoot(), "ledger.jsonl"), silentLogger);
    const failed = ledger.begin(usage({ tool_call_id: "call-failed" }));
    ledger.settle(failed.id, "failed", { error: "nope" });
    const ok = ledger.begin(usage({ tool_call_id: "call-ok", skill_id: "poster", total_credits: 30, quantity: 1 }));
    ledger.settle(ok.id, "succeeded", { image_urls: ["https://img/p.png"] });
    const pending = ledger.begin(usage({ tool_call_id: "call-pending", skill_id: "poster", total_credits: 30 }));

    expect(ledger.findSucceededToolCall("1", "s1", "call-failed")).toBeUndefined();
    const summary = ledger.summary({ uid: "1" });
    expect(summary.totals).toEqual({
      records: 3,
      images: 1,
      credits_succeeded: 30,
      credits_pending: 30,
      credits_failed: 60,
    });
    expect(summary.by_skill).toEqual([
      { skill_id: "poster", skill_name: "Demo", records: 2, images: 1, credits: 30 },
      { skill_id: "demo", skill_name: "Demo", records: 1, images: 0, credits: 0 },
    ]);
    expect(ledger.list({ status: "pending" }).map((item) => item.id)).toEqual([pending.id]);
    expect(ledger.list({ limit: 1 })).toHaveLength(1);
  });

  it("skips malformed lines instead of losing the ledger", () => {
    const file = join(tempRoot(), "ledger.jsonl");
    const ledger = new UsageLedger(file, silentLogger);
    ledger.begin(usage());
    appendFileSync(file, "{bad json\n", "utf8");
    const reloaded = new UsageLedger(file, silentLogger);
    expect(reloaded.list()).toHaveLength(1);
  });
});