import { Router, type Request, type Response } from "express";
import { randomUUID } from "crypto";
import { db, jobs, invoices, type Job } from "@workspace/db";
import { eq, and } from "drizzle-orm";
import { CreateJobBody } from "@workspace/api-zod";
import { lnbitsService } from "../lib/lnbits.js";
import { agentService } from "../lib/agent.js";
import { pricingService } from "../lib/pricing.js";

const router = Router();

async function getJobById(id: string): Promise<Job | null> {
  const rows = await db.select().from(jobs).where(eq(jobs.id, id)).limit(1);
  return rows[0] ?? null;
}

async function getInvoiceById(id: string) {
  const rows = await db.select().from(invoices).where(eq(invoices.id, id)).limit(1);
  return rows[0] ?? null;
}

/**
 * Checks whether the active invoice for a job has been paid and, if so,
 * advances the state machine. Returns the refreshed job after any transitions.
 */
async function advanceJob(job: Job): Promise<Job | null> {
  if (job.state === "awaiting_eval_payment" && job.evalInvoiceId) {
    const evalInvoice = await getInvoiceById(job.evalInvoiceId);
    if (!evalInvoice || evalInvoice.paid) return getJobById(job.id);

    const isPaid = await lnbitsService.checkInvoicePaid(evalInvoice.paymentHash);
    if (!isPaid) return job;

    const advanced = await db.transaction(async (tx) => {
      await tx
        .update(invoices)
        .set({ paid: true, paidAt: new Date() })
        .where(eq(invoices.id, evalInvoice.id));
      const updated = await tx
        .update(jobs)
        .set({ state: "evaluating", updatedAt: new Date() })
        .where(and(eq(jobs.id, job.id), eq(jobs.state, "awaiting_eval_payment")))
        .returning();
      return updated.length > 0;
    });

    if (!advanced) return getJobById(job.id);

    try {
      const evalResult = await agentService.evaluateRequest(job.request);

      if (evalResult.accepted) {
        const workFee = pricingService.calculateWorkFeeSats(job.request);
        const workInvoiceData = await lnbitsService.createInvoice(
          workFee,
          `Work fee for job ${job.id}`,
        );
        const workInvoiceId = randomUUID();

        await db.transaction(async (tx) => {
          await tx.insert(invoices).values({
            id: workInvoiceId,
            jobId: job.id,
            paymentHash: workInvoiceData.paymentHash,
            paymentRequest: workInvoiceData.paymentRequest,
            amountSats: workFee,
            type: "work",
            paid: false,
          });
          await tx
            .update(jobs)
            .set({
              state: "awaiting_work_payment",
              workInvoiceId,
              workAmountSats: workFee,
              updatedAt: new Date(),
            })
            .where(eq(jobs.id, job.id));
        });
      } else {
        await db
          .update(jobs)
          .set({ state: "rejected", rejectionReason: evalResult.reason, updatedAt: new Date() })
          .where(eq(jobs.id, job.id));
      }
    } catch (err) {
      const message = err instanceof Error ? err.message : "Evaluation error";
      await db
        .update(jobs)
        .set({ state: "failed", errorMessage: message, updatedAt: new Date() })
        .where(eq(jobs.id, job.id));
    }

    return getJobById(job.id);
  }

  if (job.state === "awaiting_work_payment" && job.workInvoiceId) {
    const workInvoice = await getInvoiceById(job.workInvoiceId);
    if (!workInvoice || workInvoice.paid) return getJobById(job.id);

    const isPaid = await lnbitsService.checkInvoicePaid(workInvoice.paymentHash);
    if (!isPaid) return job;

    const advanced = await db.transaction(async (tx) => {
      await tx
        .update(invoices)
        .set({ paid: true, paidAt: new Date() })
        .where(eq(invoices.id, workInvoice.id));
      const updated = await tx
        .update(jobs)
        .set({ state: "executing", updatedAt: new Date() })
        .where(and(eq(jobs.id, job.id), eq(jobs.state, "awaiting_work_payment")))
        .returning();
      return updated.length > 0;
    });

    if (!advanced) return getJobById(job.id);

    try {
      const workResult = await agentService.executeWork(job.request);
      await db
        .update(jobs)
        .set({ state: "complete", result: workResult.result, updatedAt: new Date() })
        .where(eq(jobs.id, job.id));
    } catch (err) {
      const message = err instanceof Error ? err.message : "Execution error";
      await db
        .update(jobs)
        .set({ state: "failed", errorMessage: message, updatedAt: new Date() })
        .where(eq(jobs.id, job.id));
    }

    return getJobById(job.id);
  }

  return job;
}

router.post("/jobs", async (req: Request, res: Response) => {
  const parseResult = CreateJobBody.safeParse(req.body);
  if (!parseResult.success) {
    res.status(400).json({ error: "Invalid request: 'request' string is required" });
    return;
  }
  const { request } = parseResult.data;

  try {
    const evalFee = pricingService.calculateEvalFeeSats();
    const jobId = randomUUID();
    const invoiceId = randomUUID();

    const lnbitsInvoice = await lnbitsService.createInvoice(
      evalFee,
      `Eval fee for job ${jobId}`,
    );

    await db.transaction(async (tx) => {
      await tx.insert(jobs).values({
        id: jobId,
        request,
        state: "awaiting_eval_payment",
        evalAmountSats: evalFee,
      });
      await tx.insert(invoices).values({
        id: invoiceId,
        jobId,
        paymentHash: lnbitsInvoice.paymentHash,
        paymentRequest: lnbitsInvoice.paymentRequest,
        amountSats: evalFee,
        type: "eval",
        paid: false,
      });
      await tx
        .update(jobs)
        .set({ evalInvoiceId: invoiceId, updatedAt: new Date() })
        .where(eq(jobs.id, jobId));
    });

    res.status(201).json({
      jobId,
      evalInvoice: {
        paymentRequest: lnbitsInvoice.paymentRequest,
        amountSats: evalFee,
      },
    });
  } catch (err) {
    const message = err instanceof Error ? err.message : "Failed to create job";
    res.status(500).json({ error: message });
  }
});

router.get("/jobs/:id", async (req: Request, res: Response) => {
  const { id } = req.params as { id: string };

  try {
    let job = await getJobById(id);
    if (!job) {
      res.status(404).json({ error: "Job not found" });
      return;
    }

    const advanced = await advanceJob(job);
    if (advanced) job = advanced;

    const base = { jobId: job.id, state: job.state };

    switch (job.state) {
      case "awaiting_eval_payment": {
        const inv = job.evalInvoiceId ? await getInvoiceById(job.evalInvoiceId) : null;
        res.json({
          ...base,
          ...(inv ? { evalInvoice: { paymentRequest: inv.paymentRequest, amountSats: inv.amountSats } } : {}),
        });
        break;
      }
      case "awaiting_work_payment": {
        const inv = job.workInvoiceId ? await getInvoiceById(job.workInvoiceId) : null;
        res.json({
          ...base,
          ...(inv ? { workInvoice: { paymentRequest: inv.paymentRequest, amountSats: inv.amountSats } } : {}),
        });
        break;
      }
      case "rejected":
        res.json({ ...base, reason: job.rejectionReason ?? undefined });
        break;
      case "complete":
        res.json({ ...base, result: job.result ?? undefined });
        break;
      case "failed":
        res.json({ ...base, errorMessage: job.errorMessage ?? undefined });
        break;
      default:
        res.json(base);
    }
  } catch (err) {
    const message = err instanceof Error ? err.message : "Failed to fetch job";
    res.status(500).json({ error: message });
  }
});

export default router;