import { Injectable } from "@nestjs/common";
import { TraceLogger } from "../common/trace-logger";
import { traceStorage } from "../common/trace-context";
import { Interval } from "@nestjs/schedule";
import { InjectRepository } from "@nestjs/typeorm";
import { Repository } from "typeorm";
import * as crypto from "crypto";
import { chromium } from "playwright";
import type { Browser, BrowserContext, Page } from "playwright";
import { ScenarioRunEntity } from "./scenario-run.entity";
import { ScenarioRunStepEntity } from "./scenario-run-step.entity";
import { ScenarioRunLogEntity } from "./scenario-run-log.entity";
import { ScenarioStepEntity } from "./scenario-step.entity";
import type { ScriptLogger } from "../code-executor/code-executor.service";
import { AuthService } from "../auth/auth.service";
import { CodeExecutorService } from "../code-executor/code-executor.service";
import { SessionService } from "../session/session.service";

interface ValidateResult {
  success: boolean;
  description?: string;
}

interface BrowserHandle {
  browser: Browser;
  context: BrowserContext;
  page: Page;
}

@Injectable()
export class ScenarioSchedulerService {
  private readonly logger = new TraceLogger(ScenarioSchedulerService.name);
  private readonly activeRuns = new Set<number>();
  private readonly runBrowsers = new Map<number, BrowserHandle>();

  constructor(
    @InjectRepository(ScenarioRunEntity)
    private readonly runRepo: Repository<ScenarioRunEntity>,
    @InjectRepository(ScenarioRunStepEntity)
    private readonly runStepRepo: Repository<ScenarioRunStepEntity>,
    @InjectRepository(ScenarioRunLogEntity)
    private readonly runLogRepo: Repository<ScenarioRunLogEntity>,
    private readonly authService: AuthService,
    private readonly codeExecutor: CodeExecutorService,
    private readonly sessionService: SessionService,
  ) {}

  private persistLog(
    runId: number,
    stepRunId: number | null,
    level: "log" | "warn" | "error",
    message: string,
  ): void {
    void this.runLogRepo.save(
      this.runLogRepo.create({ runId, stepRunId, level, message }),
    );
  }

  private stepLogger(stepRunId: number, runId: number): ScriptLogger {
    return (level, msg) => {
      this.logger[level](`StepRun #${stepRunId} script: ${msg}`);
      this.persistLog(runId, stepRunId, level, msg);
    };
  }

  private makeGetStepOutput(
    stepRun: ScenarioRunStepEntity,
  ): (order: number) => Promise<unknown> {
    return async (order: number) => {
      const targetOrder = order < 0 ? stepRun.order + order : order;
      if (targetOrder < 0) return null;
      const sr = await this.runStepRepo.findOne({
        where: { runId: stepRun.runId, order: targetOrder },
      });
      if (!sr?.output) return null;
      try {
        return JSON.parse(sr.output) as unknown;
      } catch {
        return sr.output;
      }
    };
  }

  // ── Job: pick up pending runs and process each to completion ─────────────

  @Interval(1000)
  async pickUpPendingRuns(): Promise<void> {
    const pending = await this.runRepo.find({ where: { status: "pending" } });
    for (const run of pending) {
      if (this.activeRuns.has(run.id)) continue;
      this.activeRuns.add(run.id);
      run.status = "in_progress";
      await this.runRepo.save(run);
      this.logger.log(`Run #${run.id} → in_progress`);
      const traceId = crypto.randomUUID();
      void traceStorage.run({ traceId }, () =>
        this.processRunToCompletion(run.id),
      );
    }
  }

  private async processRunToCompletion(runId: number): Promise<void> {
    try {
      let stepRun = await this.runStepRepo.findOne({
        where: { runId, status: "pending" },
        relations: ["scenarioStep"],
        order: { order: "ASC" },
      });
      while (stepRun) {
        await this.executeStepRun(stepRun);
        stepRun = await this.runStepRepo.findOne({
          where: { runId, status: "pending" },
          relations: ["scenarioStep"],
          order: { order: "ASC" },
        });
      }
      // Guard: if there were no steps (or all steps already resolved via passStepRun),
      // ensure the run is not left in in_progress.
      await this.runRepo
        .createQueryBuilder()
        .update()
        .set({ status: "pass" })
        .where("id = :id AND status = 'in_progress'", { id: runId })
        .execute();
    } catch (err) {
      this.logger.error(
        `Run #${runId}: unexpected error: ${(err as Error).message}`,
      );
      await this.runRepo.update(runId, { status: "fail" });
    } finally {
      this.activeRuns.delete(runId);
    }
  }

  private async executeStepRun(stepRun: ScenarioRunStepEntity): Promise<void> {
    const step = stepRun.scenarioStep as ScenarioStepEntity;

    stepRun.status = "in_progress";
    await this.runStepRepo.save(stepRun);
    this.logger.log(
      `StepRun #${stepRun.id} (run #${stepRun.runId}, step #${step.id} order=${step.order}) → in_progress`,
    );

    try {
      if (step.type === "login") {
        await this.executeLoginStep(stepRun, step);
      } else if (step.type === "sign") {
        await this.executeSignStep(stepRun, step);
      } else {
        await this.executeExecStep(stepRun, step);
      }
    } catch (err) {
      const msg = (err as Error).message ?? String(err);
      this.logger.error(`StepRun #${stepRun.id} threw: ${msg}`);
      await this.failStepRun(stepRun, msg);
    }
  }

  // ── Shared browser per run ─────────────────────────────────────────────────

  private async getOrCreateBrowserHandle(
    runId: number,
    sessionName: string,
  ): Promise<BrowserHandle> {
    const existing = this.runBrowsers.get(runId);
    if (existing) return existing;

    const session = await this.sessionService.findBySessionName(sessionName);
    if (!session) throw new Error(`Session not found: ${sessionName}`);

    const cookies = JSON.parse(session.cookies) as Parameters<
      BrowserContext["addCookies"]
    >[0];
    const localStorageData: Record<string, string> = JSON.parse(
      session.localStorage,
    );

    const browser = await chromium.launch({
      headless: true,
      // TODO: env var move to config
      executablePath: process.env.PLAYWRIGHT_CHROMIUM_EXECUTABLE_PATH,
    });
    const context = await browser.newContext();
    await context.addCookies(cookies);
    await context.addInitScript((entries: Record<string, string>) => {
      for (const [k, v] of Object.entries(entries))
        window.localStorage.setItem(k, v);
    }, localStorageData);
    const page = await context.newPage();

    const handle: BrowserHandle = { browser, context, page };
    this.runBrowsers.set(runId, handle);
    this.logger.log(`Run #${runId}: browser created (session: ${sessionName})`);
    return handle;
  }

  private async closeBrowserHandle(runId: number): Promise<void> {
    const handle = this.runBrowsers.get(runId);
    if (!handle) return;
    this.runBrowsers.delete(runId);
    try {
      await handle.browser.close();
      this.logger.log(`Run #${runId}: browser closed`);
    } catch (err) {
      this.logger.warn(
        `Run #${runId}: error closing browser: ${(err as Error).message}`,
      );
    }
  }

  // ── Login step ─────────────────────────────────────────────────────────────

  private async executeLoginStep(
    stepRun: ScenarioRunStepEntity,
    step: ScenarioStepEntity,
  ): Promise<void> {
    // execCode must be a JSON object: { "keyId": "...", "environmentName": "..." }
    let params: { keyId: string; environmentName: string };
    try {
      params = JSON.parse(step.execCode ?? "{}");
    } catch {
      throw new Error(
        "login step execCode must be valid JSON with keyId and environmentName",
      );
    }
    if (!params.keyId || !params.environmentName) {
      throw new Error(
        "login step execCode must include keyId and environmentName",
      );
    }

    const loginResult = await this.authService.login(
      params.keyId,
      params.environmentName,
      step.sessionName,
    );
    this.logger.log(
      `StepRun #${stepRun.id}: login OK, session=${loginResult.sessionName}`,
    );

    if (step.validateCode) {
      const { page, context } = await this.getOrCreateBrowserHandle(
        stepRun.runId,
        step.sessionName,
      );
      this.codeExecutor.validate(step.validateCode);
      const { result } = await this.codeExecutor.execute(
        page,
        context,
        step.validateCode,
        this.stepLogger(stepRun.id, stepRun.runId),
        this.makeGetStepOutput(stepRun),
      );
      const vr = this.parseValidateResult(result);
      if (!vr.success) throw new Error(vr.description ?? "Validation failed");
    }

    await this.passStepRun(stepRun, null);
  }

  // ── Exec step ──────────────────────────────────────────────────────────────

  private async executeExecStep(
    stepRun: ScenarioRunStepEntity,
    step: ScenarioStepEntity,
  ): Promise<void> {
    if (!step.execCode) throw new Error("exec step has no execCode");

    this.codeExecutor.validate(step.execCode);
    const { page, context } = await this.getOrCreateBrowserHandle(
      stepRun.runId,
      step.sessionName,
    );
    const getStepOutput = this.makeGetStepOutput(stepRun);
    const { result: execOutput } = await this.codeExecutor.execute(
      page,
      context,
      step.execCode,
      this.stepLogger(stepRun.id, stepRun.runId),
      getStepOutput,
    );
    this.logger.log(`StepRun #${stepRun.id}: exec OK`);

    if (step.validateCode) {
      this.codeExecutor.validate(step.validateCode);
      const { result } = await this.codeExecutor.execute(
        page,
        context,
        step.validateCode,
        this.stepLogger(stepRun.id, stepRun.runId),
        getStepOutput,
      );
      const vr = this.parseValidateResult(result);
      if (!vr.success) throw new Error(vr.description ?? "Validation failed");
    }

    await this.passStepRun(stepRun, null, execOutput);
  }

  // ── Sign step ──────────────────────────────────────────────────────────────

  private async executeSignStep(
    stepRun: ScenarioRunStepEntity,
    step: ScenarioStepEntity,
  ): Promise<void> {
    // execCode must be a JSON object: { "keyId": "..." }
    let params: { keyId: string };
    try {
      params = JSON.parse(step.execCode ?? "{}");
    } catch {
      throw new Error("sign step execCode must be valid JSON with keyId");
    }
    if (!params.keyId) throw new Error("sign step execCode must include keyId");

    const { page, context } = await this.getOrCreateBrowserHandle(
      stepRun.runId,
      step.sessionName,
    );
    await this.authService.signWithKey(params.keyId, page);
    this.logger.log(`StepRun #${stepRun.id}: sign OK`);

    if (step.validateCode) {
      this.codeExecutor.validate(step.validateCode);
      const { result } = await this.codeExecutor.execute(
        page,
        context,
        step.validateCode,
        this.stepLogger(stepRun.id, stepRun.runId),
        this.makeGetStepOutput(stepRun),
      );
      const vr = this.parseValidateResult(result);
      if (!vr.success) throw new Error(vr.description ?? "Validation failed");
    }

    await this.passStepRun(stepRun, null);
  }

  // ── Validation helper ──────────────────────────────────────────────────────

  private parseValidateResult(raw: unknown): ValidateResult {
    if (typeof raw === "boolean") return { success: raw };
    if (raw && typeof raw === "object") {
      const r = raw as Record<string, unknown>;
      return {
        success: Boolean(r["success"]),
        description:
          r["description"] != null ? String(r["description"]) : undefined,
      };
    }
    return { success: Boolean(raw) };
  }

  // ── Pass / fail helpers ────────────────────────────────────────────────────

  private async passStepRun(
    stepRun: ScenarioRunStepEntity,
    description: string | null,
    output: unknown = null,
  ): Promise<void> {
    stepRun.status = "pass";
    stepRun.description = description;
    stepRun.output =
      output !== null && output !== undefined ? JSON.stringify(output) : null;
    await this.runStepRepo.save(stepRun);
    this.logger.log(`StepRun #${stepRun.id} → pass`);

    // Find the next waiting step in this run (next by order)
    const nextStep = await this.runStepRepo.findOne({
      where: { runId: stepRun.runId, status: "waiting" },
      order: { order: "ASC" },
    });

    if (nextStep) {
      nextStep.status = "pending";
      await this.runStepRepo.save(nextStep);
    } else {
      // No more waiting steps — check if any are still in_progress/pending (shouldn't be, but guard anyway)
      const remaining = await this.runStepRepo.count({
        where: [
          { runId: stepRun.runId, status: "pending" },
          { runId: stepRun.runId, status: "in_progress" },
          { runId: stepRun.runId, status: "waiting" },
        ],
      });
      if (remaining === 0) {
        await this.closeBrowserHandle(stepRun.runId);
        await this.runRepo.update(stepRun.runId, { status: "pass" });
        this.logger.log(`Run #${stepRun.runId} → pass (all steps passed)`);
      }
    }
  }

  private async failStepRun(
    stepRun: ScenarioRunStepEntity,
    description: string,
  ): Promise<void> {
    stepRun.status = "fail";
    stepRun.description = description;
    await this.runStepRepo.save(stepRun);
    this.logger.log(`StepRun #${stepRun.id} → fail: ${description}`);

    // Cancel all remaining waiting/pending step runs in this run
    await this.runStepRepo
      .createQueryBuilder()
      .update()
      .set({ status: "cancelled" })
      .where("runId = :runId AND status IN (:...statuses)", {
        runId: stepRun.runId,
        statuses: ["waiting", "pending"],
      })
      .execute();

    this.logger.log(`Run #${stepRun.runId}: remaining steps cancelled`);

    await this.closeBrowserHandle(stepRun.runId);
    await this.runRepo.update(stepRun.runId, { status: "fail" });
    this.logger.log(`Run #${stepRun.runId} → fail`);
  }
}