/**
 * /api/admin/evolution — Wave B online-evolution control plane.
 *
 * Endpoints (all admin-gated):
 *   GET  /admin/evolution/networks
 *   GET  /admin/evolution/networks/:networkId/fitness
 *   GET  /admin/evolution/networks/:networkId/events
 *   GET  /admin/evolution/networks/:networkId/shadow
 *   GET  /admin/evolution/networks/:networkId/promotions
 *   GET  /admin/evolution/networks/:networkId/regression
 *   POST /admin/evolution/networks/:networkId/regression
 *   POST /admin/evolution/networks/:networkId/triggers/evaluate
 *   POST /admin/evolution/networks/:networkId/promote
 *   POST /admin/evolution/networks/:networkId/rollback-tick
 *
 * The control plane is read-mostly; the three POST endpoints exist so
 * an operator can manually drive the loop while the cron worker is
 * being wired (the cron worker itself is intentionally out of scope —
 * it just calls the same functions on a schedule).
 */
import { Router, type IRouter, type RequestHandler } from "express";
import { and, asc, desc, eq, gte, inArray } from "drizzle-orm";
import {
  db,
  networkEvolutionEvents,
  networkPromotions,
  networkVersions,
  toolNetworks,
} from "@workspace/db";
import { requireAuth, requireAdmin } from "../middlewares/auth";
import { logger } from "../lib/logger";
import { rollingFitness } from "../lib/evolution/fitness";
import { evaluateTriggers } from "../lib/evolution/triggers";
import {
  computeShadowBudget,
  getMostRecentShadowVariantId,
  summariseShadow,
  type ShadowSummary,
} from "../lib/evolution/shadow";
import type { ShadowActivePairing } from "../lib/evolution/shadow-core";
import { listEvents, recordEvent } from "../lib/evolution/events";
import {
  DEFAULT_EVOLUTION_STRATEGY,
  getEvolutionStrategy,
  listEvolutionStrategyNames,
} from "../lib/evolution/strategies";
import { attemptAutoPromote } from "../lib/evolution/promote";
import { tickRollbackWatch } from "../lib/evolution/rollback";
import { runEvolutionTick } from "../lib/evolution/scheduler";
import {
  archiveSample,
  listSamples,
  runSuiteAgainstVariant,
} from "../lib/evolution/regression-suite";

const router: IRouter = Router();
const adminGuard = [requireAuth, requireAdmin] as const;

const clampInt = (raw: unknown, def: number, min: number, max: number): number => {
  const n = Number(raw);
  if (!Number.isFinite(n)) return def;
  const i = Math.floor(n);
  if (i < min) return min;
  if (i > max) return max;
  return i;
};

class HttpError extends Error {
  status: number;
  code: string;
  constructor(status: number, code: string, msg?: string) {
    super(msg ?? code);
    this.status = status;
    this.code = code;
  }
}

const sendError = (
  res: Parameters<RequestHandler>[1],
  err: unknown,
  fallback: string,
): void => {
  if (err instanceof HttpError) {
    res.status(err.status).json({ error: err.code });
    return;
  }
  // Map common domain errors thrown as plain Error("...not_found"/"invalid_state...")
  // by the evolution lib into 4xx responses instead of generic 500s.
  const msg = err instanceof Error ? err.message : "";
  if (/not[_\s-]?found/i.test(msg)) {
    res.status(404).json({ error: msg.replace(/\s+/g, "_") });
    return;
  }
  if (/invalid|missing|required|already|conflict/i.test(msg)) {
    res.status(409).json({ error: msg.replace(/\s+/g, "_") });
    return;
  }
  res.status(500).json({ error: fallback });
};

const listNetworks: RequestHandler = async (_req, res) => {
  try {
    const nets = await db
      .select()
      .from(toolNetworks)
      .orderBy(desc(toolNetworks.updatedAt));
    const out = await Promise.all(
      nets.map(async (n) => {
        let fitness = null;
        if (n.activeVariantId) {
          fitness = await rollingFitness(
            n.id,
            n.activeVariantId,
            n.problemClassPath,
          );
        }
        const shadowBudget = await computeShadowBudget(n.id);
        // Task #228 — surface 当前 evolutionStrategy, 让 Admin UI
        // 可以渲染 "切换策略" 按钮的当前状态。缺省 (jsonb 缺字段) 时
        // 显式回退到 DEFAULT_EVOLUTION_STRATEGY, 与 builder.ts 选择
        // 策略时的回退一致。
        const cfg = (n.config ?? {}) as Record<string, unknown>;
        const evolutionStrategy =
          typeof cfg["evolutionStrategy"] === "string"
            ? (cfg["evolutionStrategy"] as string)
            : DEFAULT_EVOLUTION_STRATEGY;
        return {
          id: n.id,
          name: n.name,
          problemClassPath: n.problemClassPath,
          status: n.status,
          activeVariantId: n.activeVariantId,
          releaseTierFloor: n.releaseTierFloor,
          builderModelTier: n.builderModelTier,
          updatedAt: n.updatedAt,
          fitness,
          shadowBudget,
          evolutionStrategy,
        };
      }),
    );
    res.json({ networks: out });
  } catch (err) {
    logger.error({ err }, "evolution: listNetworks failed");
    sendError(res, err, "failed_to_list_networks");
  }
};

const requireNetwork = async (networkId: string) => {
  const row = (
    await db
      .select()
      .from(toolNetworks)
      .where(eq(toolNetworks.id, networkId))
      .limit(1)
  )[0];
  if (!row) throw new HttpError(404, "network_not_found");
  return row;
};

const getFitness: RequestHandler = async (req, res) => {
  const { networkId } = req.params as { networkId: string };
  const versionIdParam = (req.query.versionId as string | undefined) ?? null;
  const days = clampInt(req.query.days, 7, 1, 90);
  try {
    const network = await requireNetwork(networkId);
    const versions = await db
      .select()
      .from(networkVersions)
      .where(eq(networkVersions.networkId, networkId))
      .orderBy(desc(networkVersions.createdAt));
    const targetVersionIds = versionIdParam
      ? [versionIdParam]
      : versions.map((v) => v.id).slice(0, 5);
    const out = await Promise.all(
      targetVersionIds.map(async (vid) => ({
        versionId: vid,
        fitness: await rollingFitness(networkId, vid, network.problemClassPath, {
          windowDays: days,
        }),
      })),
    );
    res.json({ networkId, versions: out });
  } catch (err) {
    logger.error({ err, networkId }, "evolution: fitness failed");
    sendError(res, err, "failed_to_compute_fitness");
  }
};

const getEvents: RequestHandler = async (req, res) => {
  const { networkId } = req.params as { networkId: string };
  const limit = clampInt(req.query.limit, 200, 1, 500);
  try {
    await requireNetwork(networkId);
    const events = await listEvents({ networkId, limit });
    res.json({ events });
  } catch (err) {
    logger.error({ err, networkId }, "evolution: events failed");
    sendError(res, err, "failed_to_list_events");
  }
};

// Pure mapping from raw threshold events to chartable trend points.
// Exported for unit testing — the route handler below adds DB lookup and
// auth concerns on top of this. listEvents returns newest-first, but the
// chart wants oldest-first so we reverse here.
export interface BudgetTrendPoint {
  eventId: string;
  at: Date;
  thresholdMs: number;
  previousThresholdMs: number | null;
  mode: string;
  p75Ms: number | null;
  safetyFactor: number | null;
  sampleCount: number | null;
  recentSkipRatio: number;
  recentSampleCount: number;
}

export function eventsToBudgetTrendPoints(
  events: Array<{
    id: string;
    createdAt: Date;
    payload: unknown;
  }>,
): BudgetTrendPoint[] {
  const num = (v: unknown): number | null =>
    typeof v === "number" && Number.isFinite(v) ? v : null;
  return events
    .map((e) => {
      const p = (e.payload ?? {}) as Record<string, unknown>;
      const thresholdMs = num(p.thresholdMs);
      if (thresholdMs === null) return null;
      const mode = typeof p.mode === "string" ? p.mode : "unknown";
      return {
        eventId: e.id,
        at: e.createdAt,
        thresholdMs,
        previousThresholdMs: num(p.previousThresholdMs),
        mode,
        p75Ms: num(p.p75Ms),
        safetyFactor: num(p.safetyFactor),
        sampleCount: num(p.sampleCount),
        recentSkipRatio: num(p.recentSkipRatio) ?? 0,
        recentSampleCount: num(p.recentSampleCount) ?? 0,
      };
    })
    .filter((x): x is BudgetTrendPoint => x !== null)
    .reverse();
}

// Pull the recent shadow_budget_threshold events for a network and flatten
// them into a chartable point series. Each event already carries the
// threshold ms, the dynamic-mode metadata, and the recent budget-skip
// ratio observed at that moment, so the admin UI can plot drift without
// having to bucket raw shadow samples itself.
const getBudgetTrend: RequestHandler = async (req, res) => {
  const { networkId } = req.params as { networkId: string };
  const limit = clampInt(req.query.limit, 50, 1, 200);
  try {
    await requireNetwork(networkId);
    const events = await listEvents({
      networkId,
      kind: "shadow_budget_threshold",
      limit,
    });
    const points = eventsToBudgetTrendPoints(events);
    res.json({ networkId, points });
  } catch (err) {
    logger.error({ err, networkId }, "evolution: budget trend failed");
    sendError(res, err, "failed_to_load_budget_trend");
  }
};

const getShadow: RequestHandler = async (req, res) => {
  const { networkId } = req.params as { networkId: string };
  const candidateId = req.query.candidateId as string | undefined;
  if (!candidateId) {
    return res.status(400).json({ error: "candidateId_required" });
  }
  try {
    const summary = await summariseShadow(networkId, candidateId);
    res.json({ summary });
  } catch (err) {
    logger.error({ err, networkId, candidateId }, "evolution: shadow failed");
    sendError(res, err, "failed_to_summarise_shadow");
  }
};

/**
 * Wall-clock window the overview computes its summary against. Kept
 * in sync with the default in {@link summariseShadow} so the promotion
 * lookup uses exactly the same horizon as the win-delta math.
 */
const SHADOW_OVERVIEW_WINDOW_DAYS = 7;

/**
 * Promotion that ended a particular pairing in the shadow window. The
 * UI uses `eventId` to scroll/highlight the matching row in the events
 * stream and `reason` to colour the chip differently for "switched-
 * because-promoted" (`auto_promote` / `manual` / `seed`) vs
 * "switched-because-rolled-back" (`auto_rollback`).
 */
export interface PairingPromotionLink {
  promotionId: string;
  /** "manual" | "auto_promote" | "auto_rollback" | "seed" */
  reason: string;
  /** The variant that took over after this pairing's active was demoted. */
  toVariantId: string;
  createdAt: Date;
  /**
   * `network_evolution_events.id` for the matching `promote` /
   * `rollback` event — null if no event was recorded (legacy data /
   * direct DB insert). The UI links the chip to this event id.
   */
  eventId: string | null;
}

export type EnrichedShadowActivePairing = ShadowActivePairing & {
  endedByPromotion: PairingPromotionLink | null;
};

/**
 * Pure mapping: given the pairings the shadow window observed and the
 * promotions already filtered to the same window, attach the earliest
 * promotion that demoted the pairing's active variant after its last
 * sample. Exported so the route's enrichment logic is unit-testable
 * without standing up the DB / Express / events writer.
 *
 * Matching rule (see task #199): a pairing P with `lastSampleAt = T_last`
 * is considered ended by the *earliest* promotion `pr` where
 *   pr.fromVariantId === P.activeVariantId  AND
 *   pr.createdAt    >= T_last
 * The `>= T_last` clamp is what protects against a network that was
 * promoted out of and then back into the same active variant — only
 * the promotion that fires *after* the pairing's last sample matters.
 * When the pairing has no `lastSampleAt` (defensive: legacy data with
 * null timestamps), we fall back to "earliest matching promotion in
 * the window" so the link still shows up rather than disappearing.
 */
export function enrichPairingsWithPromotions(
  pairings: ReadonlyArray<ShadowActivePairing>,
  promotions: ReadonlyArray<{
    id: string;
    fromVariantId: string | null;
    toVariantId: string;
    reason: string;
    createdAt: Date;
  }>,
  eventByPromotionId: ReadonlyMap<string, string>,
): EnrichedShadowActivePairing[] {
  // Promotions arrive in any order; sort once ascending so the
  // `find(...)` below picks the earliest match.
  const byTimeAsc = promotions
    .slice()
    .sort((a, b) => a.createdAt.getTime() - b.createdAt.getTime());
  return pairings.map((p) => {
    const lastTs = p.lastSampleAt ? p.lastSampleAt.getTime() : null;
    const pr = byTimeAsc.find(
      (x) =>
        x.fromVariantId === p.activeVariantId &&
        (lastTs === null || x.createdAt.getTime() >= lastTs),
    );
    if (!pr) return { ...p, endedByPromotion: null };
    return {
      ...p,
      endedByPromotion: {
        promotionId: pr.id,
        reason: pr.reason,
        toVariantId: pr.toVariantId,
        createdAt: pr.createdAt,
        eventId: eventByPromotionId.get(pr.id) ?? null,
      },
    };
  });
}

/**
 * Per-network roll-up of "what's the candidate currently being shadow-
 * tested doing?" — sample N, mean active vs shadow score, win delta,
 * critical-signal count, budget-skipped %, plus links to the most
 * recent shadow_started / shadow_runner_error / shadow_budget_skipped
 * events for triage. Used by the Evolution Live admin page so an
 * operator can see at a glance whether `attemptAutoPromote` is likely
 * to fire (or whether the candidate is silently regressing).
 *
 * Returns one row per network with at least one shadow sample. Networks
 * with no shadow samples yet are still included with a null `summary`
 * so the operator can confirm a fresh deploy is wired up but quiet.
 *
 * Each pairing in `summary.activePairings` is enriched with the
 * promotion event (if any) that ended it, so the UI can render the
 * promotion timestamp inline with the pairing chip and visually
 * separate auto-promote boundaries from rollback boundaries.
 */
const getShadowOverview: RequestHandler = async (_req, res) => {
  try {
    const nets = await db
      .select()
      .from(toolNetworks)
      .orderBy(desc(toolNetworks.updatedAt));
    const since = new Date(
      Date.now() - SHADOW_OVERVIEW_WINDOW_DAYS * 24 * 60 * 60 * 1000,
    );
    const items = await Promise.all(
      nets.map(async (n) => {
        const shadowVariantId = await getMostRecentShadowVariantId(n.id);
        let summary: (Omit<ShadowSummary, "activePairings"> & {
          activePairings: EnrichedShadowActivePairing[];
        }) | null = null;
        let budgetSkippedPct: number | null = null;
        if (shadowVariantId) {
          const raw = await summariseShadow(n.id, shadowVariantId);
          // Promotions and their matching events for the same window
          // we summarised. Both reads run in parallel because they hit
          // independent indexes.
          const [promos, promoEvents] = await Promise.all([
            db
              .select({
                id: networkPromotions.id,
                fromVariantId: networkPromotions.fromVariantId,
                toVariantId: networkPromotions.toVariantId,
                reason: networkPromotions.reason,
                createdAt: networkPromotions.createdAt,
              })
              .from(networkPromotions)
              .where(
                and(
                  eq(networkPromotions.networkId, n.id),
                  gte(networkPromotions.createdAt, since),
                ),
              )
              .orderBy(asc(networkPromotions.createdAt)),
            db
              .select({
                id: networkEvolutionEvents.id,
                promotionId: networkEvolutionEvents.promotionId,
              })
              .from(networkEvolutionEvents)
              .where(
                and(
                  eq(networkEvolutionEvents.networkId, n.id),
                  inArray(networkEvolutionEvents.kind, ["promote", "rollback"]),
                  gte(networkEvolutionEvents.createdAt, since),
                ),
              ),
          ]);
          const eventByPromotionId = new Map<string, string>();
          for (const e of promoEvents) {
            if (e.promotionId) eventByPromotionId.set(e.promotionId, e.id);
          }
          const enrichedPairings = enrichPairingsWithPromotions(
            raw.activePairings,
            promos,
            eventByPromotionId,
          );
          summary = { ...raw, activePairings: enrichedPairings };
          const total = summary.sampleCount + summary.budgetSkippedCount;
          budgetSkippedPct = total > 0 ? summary.budgetSkippedCount / total : 0;
        }
        // Pull the most recent triage events independently so a network
        // that has never had a runner error still gets an empty list
        // for that kind, rather than a silent "no events" merger.
        const [shadowStarted, runnerError, budgetSkipped] = await Promise.all([
          listEvents({ networkId: n.id, kind: "shadow_started", limit: 5 }),
          listEvents({
            networkId: n.id,
            kind: "shadow_runner_error",
            limit: 5,
          }),
          listEvents({
            networkId: n.id,
            kind: "shadow_budget_skipped",
            limit: 5,
          }),
        ]);
        return {
          networkId: n.id,
          networkName: n.name,
          problemClassPath: n.problemClassPath,
          activeVariantId: n.activeVariantId,
          shadowVariantId,
          summary,
          winDelta: summary ? summary.deltaMean : null,
          budgetSkippedPct,
          events: {
            shadow_started: shadowStarted,
            shadow_runner_error: runnerError,
            shadow_budget_skipped: budgetSkipped,
          },
        };
      }),
    );
    res.json({ items });
  } catch (err) {
    logger.error({ err }, "evolution: shadow overview failed");
    sendError(res, err, "failed_to_load_shadow_overview");
  }
};

const getPromotions: RequestHandler = async (req, res) => {
  const { networkId } = req.params as { networkId: string };
  try {
    await requireNetwork(networkId);
    const rows = await db
      .select()
      .from(networkPromotions)
      .where(eq(networkPromotions.networkId, networkId))
      .orderBy(desc(networkPromotions.createdAt))
      .limit(50);
    res.json({ promotions: rows });
  } catch (err) {
    logger.error({ err, networkId }, "evolution: promotions failed");
    sendError(res, err, "failed_to_list_promotions");
  }
};

const getRegression: RequestHandler = async (req, res) => {
  const { networkId } = req.params as { networkId: string };
  try {
    await requireNetwork(networkId);
    const samples = await listSamples(networkId, "active");
    res.json({ samples });
  } catch (err) {
    logger.error({ err, networkId }, "evolution: regression list failed");
    sendError(res, err, "failed_to_list_regression");
  }
};

const postRegression: RequestHandler = async (req, res) => {
  const { networkId } = req.params as { networkId: string };
  const body = (req.body ?? {}) as {
    problemClassPath?: unknown;
    label?: unknown;
    inputPayload?: unknown;
    expectedFloor?: unknown;
    expectedShape?: unknown;
  };
  if (typeof body.problemClassPath !== "string" || !body.problemClassPath) {
    return res.status(400).json({ error: "problemClassPath_required" });
  }
  if (!body.inputPayload || typeof body.inputPayload !== "object") {
    return res.status(400).json({ error: "inputPayload_required" });
  }
  try {
    const row = await archiveSample({
      networkId,
      problemClassPath: body.problemClassPath,
      label: typeof body.label === "string" ? body.label : "",
      inputPayload: body.inputPayload as Record<string, unknown>,
      expectedFloor:
        typeof body.expectedFloor === "number" ? body.expectedFloor : undefined,
      expectedShape:
        body.expectedShape && typeof body.expectedShape === "object"
          ? (body.expectedShape as Record<string, unknown>)
          : undefined,
      createdBy: req.user?.id ?? "admin",
    });
    res.status(201).json({ sample: row });
  } catch (err) {
    logger.error({ err, networkId }, "evolution: regression archive failed");
    res.status(500).json({ error: "failed_to_archive_sample" });
  }
};

const postEvaluate: RequestHandler = async (req, res) => {
  const { networkId } = req.params as { networkId: string };
  try {
    const evalResult = await evaluateTriggers(networkId);
    res.json({ evaluation: evalResult });
  } catch (err) {
    logger.error({ err, networkId }, "evolution: evaluate failed");
    res.status(500).json({ error: "failed_to_evaluate" });
  }
};

const postPromote: RequestHandler = async (req, res) => {
  const { networkId } = req.params as { networkId: string };
  const body = (req.body ?? {}) as {
    candidateVariantId?: unknown;
    minSamplesOverride?: unknown;
  };
  if (typeof body.candidateVariantId !== "string" || !body.candidateVariantId) {
    return res.status(400).json({ error: "candidateVariantId_required" });
  }
  try {
    const decision = await attemptAutoPromote({
      networkId,
      candidateVariantId: body.candidateVariantId,
      actor: req.user?.id ? `admin:${req.user.id}` : "admin_manual",
      minSamplesOverride:
        typeof body.minSamplesOverride === "number"
          ? body.minSamplesOverride
          : undefined,
    });
    res.json({ decision });
  } catch (err) {
    logger.error({ err, networkId }, "evolution: promote failed");
    res.status(500).json({ error: "failed_to_promote" });
  }
};

const postRollbackTick: RequestHandler = async (_req, res) => {
  try {
    const results = await tickRollbackWatch();
    res.json({ results });
  } catch (err) {
    logger.error({ err }, "evolution: rollback tick failed");
    res.status(500).json({ error: "failed_to_tick_rollback" });
  }
};

/**
 * Task #228 — admin 切换 evolutionStrategy 端点。
 *
 * PATCH /admin/evolution/networks/:networkId/strategy { strategy: string }
 *
 * 行为:
 *   1. 校验 strategy 是已注册策略名;不在注册表 → 400 unknown_strategy
 *      (列出可选名给前端做下拉提示)。
 *   2. 把 tool_networks.config.evolutionStrategy 写成新值
 *      (merge, 不动其他 config 字段)。
 *   3. 写一条 strategy_changed 事件, payload = {from, to, actorId},
 *      Builder Proposals 卡片 / 审计回放可读到。
 *   4. 切换不影响已存在 candidate; 下一次 scheduler-tick 才会用新策略。
 */
/**
 * Task #228 — 提出 PATCH /strategy 入参校验为可单测的纯函数。
 *
 * 把"body 形状 + 策略名注册表查"两个可纯函数化的检查从 handler 抽出来,
 * 便于在 routes/__tests__ 里不起 DB 也能回归 (a) 缺 strategy 字段,
 * (b) strategy 字段非字符串, (c) 未注册策略名 → 列出可选名 这三条契约。
 *
 * Handler 仍要做 requireNetwork → db.update → recordEvent 这些有副作用
 * 的步骤, 但那些走另外的 e2e 测试覆盖。
 */
export interface PatchStrategyValidation {
  ok: boolean;
  status: number;
  body: { error?: string; available?: string[]; strategy?: string };
}

export function validatePatchStrategyBody(
  raw: unknown,
): PatchStrategyValidation {
  const body = (raw ?? {}) as { strategy?: unknown };
  if (typeof body.strategy !== "string" || body.strategy.length === 0) {
    return { ok: false, status: 400, body: { error: "strategy_required" } };
  }
  const target = body.strategy;
  if (!getEvolutionStrategy(target)) {
    return {
      ok: false,
      status: 400,
      body: {
        error: "unknown_strategy",
        available: listEvolutionStrategyNames(),
      },
    };
  }
  return { ok: true, status: 200, body: { strategy: target } };
}

const patchStrategy: RequestHandler = async (req, res) => {
  const { networkId } = req.params as { networkId: string };
  const validation = validatePatchStrategyBody(req.body);
  if (!validation.ok) {
    return res.status(validation.status).json(validation.body);
  }
  const target = validation.body.strategy as string;
  try {
    const network = await requireNetwork(networkId);
    const priorCfg = (network.config ?? {}) as Record<string, unknown>;
    const from =
      typeof priorCfg["evolutionStrategy"] === "string"
        ? (priorCfg["evolutionStrategy"] as string)
        : DEFAULT_EVOLUTION_STRATEGY;
    if (from === target) {
      return res.json({
        ok: true,
        strategy: target,
        unchanged: true,
        available: listEvolutionStrategyNames(),
      });
    }
    const merged = { ...priorCfg, evolutionStrategy: target };
    await db
      .update(toolNetworks)
      .set({ config: merged, updatedAt: new Date() })
      .where(eq(toolNetworks.id, networkId));
    try {
      await recordEvent({
        networkId,
        kind: "strategy_changed",
        payload: {
          from,
          to: target,
          actorId: req.user?.id ?? "admin_manual",
        },
      });
    } catch (eventErr) {
      // 写事件失败不应回滚 config 更新 — 事件流是观测层, 不是事实层。
      logger.warn(
        { err: eventErr, networkId, from, to: target },
        "evolution: strategy_changed event write failed (suppressed)",
      );
    }
    res.json({
      ok: true,
      strategy: target,
      from,
      available: listEvolutionStrategyNames(),
    });
  } catch (err) {
    logger.error({ err, networkId, target }, "evolution: patch strategy failed");
    sendError(res, err, "failed_to_patch_strategy");
  }
};

const postSchedulerTick: RequestHandler = async (_req, res) => {
  try {
    const summary = await runEvolutionTick();
    res.json({ summary });
  } catch (err) {
    logger.error({ err }, "evolution: scheduler tick failed");
    res.status(500).json({ error: "failed_to_run_scheduler_tick" });
  }
};

const postRunSuite: RequestHandler = async (req, res) => {
  const { networkId } = req.params as { networkId: string };
  const body = (req.body ?? {}) as { variantId?: unknown };
  if (typeof body.variantId !== "string" || !body.variantId) {
    return res.status(400).json({ error: "variantId_required" });
  }
  try {
    const result = await runSuiteAgainstVariant(networkId, body.variantId);
    res.json({ result });
  } catch (err) {
    logger.error({ err, networkId }, "evolution: regression run failed");
    res.status(500).json({ error: "failed_to_run_suite" });
  }
};

/**
 * Wave B step 2 — recent builder activity timeline.
 *
 * Returns the last `limit` `builder_proposed` / `builder_no_candidate` /
 * `builder_error` events emitted by `runEvolutionBuilder`. Optionally
 * filters by network. The admin Evolution Live page renders the
 * stream as a small "Builder Proposals" card so operators can see
 * which strategies are firing, what configs they emit, and which
 * networks have stalled (`no_candidate`) or are throwing
 * (`builder_error`).
 *
 * Read-only and cheap: pulls each kind in parallel and merges. The
 * three independent `listEvents` calls each cap at 200 server-side,
 * so the worst case is 600 rows merged + sliced — well below any
 * sensible page payload.
 */
const getBuilderEvents: RequestHandler = async (req, res) => {
  const networkId =
    typeof req.query.networkId === "string" ? req.query.networkId : undefined;
  const limit = clampInt(req.query.limit, 50, 1, 200);
  // Time window: default to last 24h so the admin card never balloons
  // across a long-running deploy. Operators can widen via ?hours=72
  // (capped at 168 = one week) or pin a custom point with
  // ?since=<ISO timestamp>. `since` wins if both are supplied.
  const hours = clampInt(req.query.hours, 24, 1, 168);
  let cutoffMs = Date.now() - hours * 60 * 60 * 1000;
  if (typeof req.query.since === "string" && req.query.since.length > 0) {
    const parsed = Date.parse(req.query.since);
    if (Number.isFinite(parsed)) {
      cutoffMs = parsed;
    }
  }
  try {
    if (networkId) {
      await requireNetwork(networkId);
    }
    const [proposed, none, errored] = await Promise.all([
      listEvents({ networkId, kind: "builder_proposed", limit }),
      listEvents({ networkId, kind: "builder_no_candidate", limit }),
      listEvents({ networkId, kind: "builder_error", limit }),
    ]);
    const events = [...proposed, ...none, ...errored]
      .filter((e) => e.createdAt.getTime() >= cutoffMs)
      .sort((a, b) => b.createdAt.getTime() - a.createdAt.getTime())
      .slice(0, limit);
    res.json({ events, windowHours: hours, since: new Date(cutoffMs).toISOString() });
  } catch (err) {
    logger.error({ err, networkId }, "evolution: builder events failed");
    sendError(res, err, "failed_to_list_builder_events");
  }
};

router.get("/admin/evolution/networks", ...adminGuard, listNetworks);
router.get(
  "/admin/evolution/networks/:networkId/fitness",
  ...adminGuard,
  getFitness,
);
router.get(
  "/admin/evolution/networks/:networkId/events",
  ...adminGuard,
  getEvents,
);
router.get(
  "/admin/evolution/networks/:networkId/budget-trend",
  ...adminGuard,
  getBudgetTrend,
);
router.get(
  "/admin/evolution/networks/:networkId/shadow",
  ...adminGuard,
  getShadow,
);
router.get(
  "/admin/evolution/shadow-overview",
  ...adminGuard,
  getShadowOverview,
);
router.get(
  "/admin/evolution/networks/:networkId/promotions",
  ...adminGuard,
  getPromotions,
);
router.get(
  "/admin/evolution/networks/:networkId/regression",
  ...adminGuard,
  getRegression,
);
router.post(
  "/admin/evolution/networks/:networkId/regression",
  ...adminGuard,
  postRegression,
);
router.post(
  "/admin/evolution/networks/:networkId/regression/run",
  ...adminGuard,
  postRunSuite,
);
router.post(
  "/admin/evolution/networks/:networkId/triggers/evaluate",
  ...adminGuard,
  postEvaluate,
);
router.post(
  "/admin/evolution/networks/:networkId/promote",
  ...adminGuard,
  postPromote,
);
router.patch(
  "/admin/evolution/networks/:networkId/strategy",
  ...adminGuard,
  patchStrategy,
);
router.post(
  "/admin/evolution/rollback-tick",
  ...adminGuard,
  postRollbackTick,
);
router.post(
  "/admin/evolution/scheduler-tick",
  ...adminGuard,
  postSchedulerTick,
);
router.get(
  "/admin/evolution/builder-events",
  ...adminGuard,
  getBuilderEvents,
);

export default router;

// Test-only handler exports — surfaced so route unit tests can call
// each one without spinning up the auth middleware chain.
export const _handlers = {
  listNetworks,
  getFitness,
  getEvents,
  getBudgetTrend,
  getShadow,
  getShadowOverview,
  getPromotions,
  getRegression,
  postRegression,
  postEvaluate,
  postPromote,
  postRollbackTick,
  postSchedulerTick,
  postRunSuite,
  getBuilderEvents,
  patchStrategy,
};