/**
 * Auto-combo scoring, intent extraction, request-tag routing, candidate-pool
 * expansion and the quota-soft execution-candidate registry — extracted from
 * combo.ts (Quality Gate v2 / Fase 9, combo split D8 — reduced).
 *
 * Logic is unchanged (byte-identical move); the moved public symbols
 * (QUOTA_SOFT_DEPRIORITIZE_FACTOR, setCandidateQuotaSoftPenalty, scoreAutoTargets,
 * expandAutoComboCandidatePool) are re-exported from combo.ts for backward
 * compatibility — including chatCore.ts's dynamic `import("../services/combo")`
 * which reads setCandidateQuotaSoftPenalty + QUOTA_SOFT_DEPRIORITIZE_FACTOR.
 *
 * The _activeExecutionCandidates registry Map MUST stay a single instance, so it
 * and its three mutators live together here.
 *
 * NOTE: buildAutoCandidates (and its two private-only helpers
 * calculateTargetContextAffinity / getBootstrapLatencyMs) deliberately stay in
 * combo.ts — it is the sole user of the internal reset-window helpers
 * (resolveResetWindowConfig / fetchResetAwareQuotaWithCache /
 * calculateResetWindowAffinity), so keeping it there avoids a combo ⇄ autoStrategy
 * import cycle. This module never imports from the combo barrel.
 */

import { isRecord } from "./comboData.ts";
import type { AutoProviderCandidate, ComboLike, ResolvedComboTarget } from "./types.ts";
import { extractSessionAffinityKey } from "@/sse/services/auth";
import { DEFAULT_INTENT_CONFIG, type IntentClassifierConfig } from "../intentClassifier.ts";
import { getTaskFitness } from "../autoCombo/taskFitness.ts";
import {
  calculateFactors,
  calculateScore,
  type ProviderCandidate,
  type ScoringWeights,
} from "../autoCombo/scoring.ts";
import type { RoutingHint } from "../manifestAdapter";
import { getProviderConnections } from "../../../src/lib/db/providers";
import { getProviderModels } from "../../config/providerModels.ts";
import {
  getConnectionRoutingTags,
  matchesRoutingTags,
  resolveRequestRoutingTags,
} from "../../../src/domain/tagRouter.ts";

// Quota Share soft-policy deprioritization factor (B17).
// When a candidate has quotaSoftPenalty === true, its auto-combo score is
// multiplied by this factor so over-quota-soft keys are de-prioritized
// without being fully blocked (that is done by "hard" policy).
// Override via QUOTA_SOFT_DEPRIORITIZE_FACTOR env var (range 0..1, default 0.7).
export const QUOTA_SOFT_DEPRIORITIZE_FACTOR = Number(
  process.env.QUOTA_SOFT_DEPRIORITIZE_FACTOR ?? "0.7"
);

// #4540: Status soft-deprioritization factor.
// When the quota-preflight HARD cutoff is OFF (default), a candidate whose connection
// is in a terminal/transient unavailable status (credits_exhausted / rate_limited /
// banned / expired / future-dated unavailable) is NOT hard-blocked — instead its
// auto-combo score is multiplied by this factor so an exhausted provider ranks strictly
// below an otherwise-identical healthy one, without surfacing a misleading 429.
// Override via STATUS_SOFT_DEPRIORITIZE_FACTOR env var (range 0..1, default 0.5).
export const STATUS_SOFT_DEPRIORITIZE_FACTOR = Number(
  process.env.STATUS_SOFT_DEPRIORITIZE_FACTOR ?? "0.5"
);

// G2: Module-level registry of active combo execution candidates.
// Maps executionKey → Map<stepId, candidate mutable ref>.
// Populated by buildAutoCandidates registrations; cleaned up after each execution.
// This allows chatCore.ts to mark a candidate's quotaSoftPenalty flag so that
// subsequent scoring iterations (auto-combo fallback) deprioritize it.
const _activeExecutionCandidates = new Map<string, Map<string, { quotaSoftPenalty?: boolean }>>();

/**
 * Mark a specific candidate (by comboExecutionKey + stepId) with soft quota penalty.
 * Called from chatCore.ts when enforceQuotaShare returns a "soft deprioritize" decision.
 * The flag is read on subsequent auto-combo scoring iterations (fallback chain)
 * within the same combo execution via scoreAutoTargets → QUOTA_SOFT_DEPRIORITIZE_FACTOR.
 *
 * Guards:
 * - null executionKey or stepId → no-op (non-combo or context not available).
 * - unknown executionKey → no-op (candidate not yet registered or already cleaned up).
 * - Idempotent: calling twice with the same (key, stepId, true) is safe.
 */
export function setCandidateQuotaSoftPenalty(
  comboExecutionKey: string | null,
  comboStepId: string | null,
  penalty: boolean
): void {
  if (!comboExecutionKey || !comboStepId) return;
  const byStep = _activeExecutionCandidates.get(comboExecutionKey);
  if (!byStep) return;
  const candidate = byStep.get(comboStepId);
  if (candidate) {
    candidate.quotaSoftPenalty = penalty;
  }
}

/**
 * Register candidates for a combo execution so setCandidateQuotaSoftPenalty can
 * locate them by (executionKey, stepId).
 * Each candidate object is stored by reference — mutations via setCandidateQuotaSoftPenalty
 * propagate back to the original candidate array used by scoreAutoTargets.
 * @internal — not exported; only called within combo.ts by buildAutoCandidates callers.
 */
export function _registerExecutionCandidates(
  candidates: Array<{ executionKey: string; stepId: string; quotaSoftPenalty?: boolean }>
): void {
  for (const candidate of candidates) {
    if (!candidate.executionKey) continue;
    let byStep = _activeExecutionCandidates.get(candidate.executionKey);
    if (!byStep) {
      byStep = new Map();
      _activeExecutionCandidates.set(candidate.executionKey, byStep);
    }
    byStep.set(candidate.stepId, candidate);
  }
}

/**
 * Unregister all candidates for a given execution key once the execution completes.
 * Prevents unbounded memory growth.
 * @internal — not exported; called after each handleComboChat iteration.
 */
export function _unregisterExecutionCandidates(executionKeys: string[]): void {
  for (const key of executionKeys) {
    _activeExecutionCandidates.delete(key);
  }
}

function toTextContent(content: unknown): string {
  if (typeof content === "string") return content;
  if (!Array.isArray(content)) return "";
  return content
    .map((part) => {
      if (!isRecord(part)) return "";
      if (typeof part.text === "string") return part.text;
      return "";
    })
    .join("\n");
}

export function extractPromptForIntent(body: Record<string, unknown> | null | undefined): string {
  if (!body || typeof body !== "object") return "";

  const fromMessages = Array.isArray(body.messages)
    ? [...body.messages].reverse().find((m) => isRecord(m) && m.role === "user")
    : null;
  if (isRecord(fromMessages)) return toTextContent(fromMessages.content);

  if (typeof body.input === "string") return body.input;
  if (Array.isArray(body.input)) {
    const text = body.input
      .map((item) => {
        if (!isRecord(item)) return "";
        if (typeof item.content === "string") return item.content;
        if (typeof item.text === "string") return item.text;
        return "";
      })
      .filter(Boolean)
      .join("\n");
    if (text) return text;
  }

  if (typeof body.prompt === "string") return body.prompt;
  return "";
}

export function mapIntentToTaskType(intent: string): "coding" | "analysis" | "default" {
  switch (intent) {
    case "code":
      return "coding";
    case "reasoning":
      return "analysis";
    case "simple":
      return "default";
    case "medium":
    default:
      return "default";
  }
}

function toStringArray(input: unknown): string[] {
  if (Array.isArray(input)) {
    return input.map((v) => (typeof v === "string" ? v.trim() : "")).filter(Boolean);
  }
  if (typeof input === "string") {
    return input
      .split(",")
      .map((v) => v.trim())
      .filter(Boolean);
  }
  return [];
}

export function getIntentConfig(
  settings: Record<string, unknown> | null | undefined,
  combo: ComboLike
): IntentClassifierConfig {
  const resolvedSettings = settings || {};
  const comboAutoConfig = combo?.autoConfig || {};
  const comboConfigAuto = isRecord(combo?.config?.auto) ? combo.config.auto : {};
  const comboIntentConfig =
    (isRecord(comboAutoConfig.intentConfig) && comboAutoConfig.intentConfig) ||
    (isRecord(comboConfigAuto.intentConfig) && comboConfigAuto.intentConfig) ||
    (isRecord(combo?.config?.intentConfig) && combo.config.intentConfig) ||
    {};

  return {
    ...DEFAULT_INTENT_CONFIG,
    ...comboIntentConfig,
    ...(typeof resolvedSettings.intentDetectionEnabled === "boolean"
      ? { enabled: resolvedSettings.intentDetectionEnabled }
      : {}),
    ...(Number.isFinite(Number(resolvedSettings.intentSimpleMaxWords))
      ? { simpleMaxWords: Number(resolvedSettings.intentSimpleMaxWords) }
      : {}),
    ...(toStringArray(resolvedSettings.intentExtraCodeKeywords).length > 0
      ? { extraCodeKeywords: toStringArray(resolvedSettings.intentExtraCodeKeywords) }
      : {}),
    ...(toStringArray(resolvedSettings.intentExtraReasoningKeywords).length > 0
      ? { extraReasoningKeywords: toStringArray(resolvedSettings.intentExtraReasoningKeywords) }
      : {}),
    ...(toStringArray(resolvedSettings.intentExtraSimpleKeywords).length > 0
      ? { extraSimpleKeywords: toStringArray(resolvedSettings.intentExtraSimpleKeywords) }
      : {}),
  };
}

export async function applyRequestTagRouting(
  targets: ResolvedComboTarget[],
  body: Record<string, unknown> | null | undefined,
  log: { info?: (...args: unknown[]) => void; warn?: (...args: unknown[]) => void }
): Promise<ResolvedComboTarget[]> {
  const { tags, matchMode } = resolveRequestRoutingTags(body);
  if (tags.length === 0 || targets.length === 0) {
    return targets;
  }

  const providerIds = Array.from(
    new Set(targets.map((target) => target.providerId || target.provider))
  ).filter(
    (providerId): providerId is string => typeof providerId === "string" && providerId.length > 0
  );
  const providerConnections = new Map<string, Array<Record<string, unknown>>>();

  await Promise.all(
    providerIds.map(async (providerId) => {
      try {
        const connections = await getProviderConnections({ provider: providerId, isActive: true });
        providerConnections.set(
          providerId,
          Array.isArray(connections) ? (connections as Array<Record<string, unknown>>) : []
        );
      } catch (error) {
        log.warn?.(
          "COMBO",
          `Tag routing failed to load connections for provider=${providerId}: ${error instanceof Error ? error.message : String(error)}`
        );
        providerConnections.set(providerId, []);
      }
    })
  );

  const filteredTargets = targets.reduce<ResolvedComboTarget[]>((acc, target) => {
    const providerKey = target.providerId || target.provider;
    const candidateConnections =
      providerConnections.get(providerKey)?.filter((connection) => {
        const connectionId =
          typeof connection.id === "string" && connection.id.trim().length > 0
            ? connection.id
            : null;
        if (!connectionId) return false;
        if (target.connectionId) {
          return connectionId === target.connectionId;
        }
        return true;
      }) || [];

    const matchedConnectionIds = candidateConnections
      .filter((connection) =>
        matchesRoutingTags(
          getConnectionRoutingTags(connection.providerSpecificData),
          tags,
          matchMode
        )
      )
      .map((connection) => connection.id)
      .filter((connectionId): connectionId is string => typeof connectionId === "string");

    if (matchedConnectionIds.length === 0) {
      return acc;
    }

    if (target.connectionId) {
      acc.push(target);
      return acc;
    }

    // #3266: when a step already carries an account allowlist, intersect it with
    // the tag-matched connections (most-restrictive wins). An empty intersection
    // means no connection satisfies both constraints, so the target is dropped —
    // the same outcome the `matchedConnectionIds.length === 0` guard above yields.
    const tagMatched = Array.from(new Set(matchedConnectionIds));
    const stepAllow = Array.isArray(target.allowedConnectionIds)
      ? target.allowedConnectionIds.filter(
          (id): id is string => typeof id === "string" && id.length > 0
        )
      : null;
    const effectiveAllow =
      stepAllow && stepAllow.length > 0
        ? tagMatched.filter((id) => stepAllow.includes(id))
        : tagMatched;

    if (effectiveAllow.length === 0) {
      return acc;
    }

    acc.push({
      ...target,
      allowedConnectionIds: effectiveAllow,
    });
    return acc;
  }, []);

  if (filteredTargets.length === 0) {
    log.info?.(
      "COMBO",
      `Tag routing matched 0/${targets.length} targets for [${tags.join(", ")}] (${matchMode}); falling back to the full target set`
    );
    return targets;
  }

  log.info?.(
    "COMBO",
    `Tag routing matched ${filteredTargets.length}/${targets.length} targets for [${tags.join(", ")}] (${matchMode})`
  );
  return filteredTargets;
}

export function scoreAutoTargets(
  targets: ResolvedComboTarget[],
  candidates: AutoProviderCandidate[],
  taskType: string | null,
  weights: ScoringWeights,
  manifestHint?: RoutingHint | null
) {
  const targetByExecutionKey = new Map(targets.map((target) => [target.executionKey, target]));
  const activeCandidates = candidates.filter((candidate) => candidate.quotaCutoffBlocked !== true);

  return activeCandidates
    .map((candidate) => {
      const baseTarget =
        targetByExecutionKey.get(candidate.executionKey) ||
        targets.find(
          (target) =>
            target.stepId === candidate.stepId ||
            (target.provider === candidate.provider && target.modelStr === candidate.modelStr)
        );
      if (!baseTarget) return null;

      const target: ResolvedComboTarget = {
        ...baseTarget,
        stepId: candidate.stepId,
        executionKey: candidate.executionKey,
        modelStr: candidate.modelStr,
        provider: candidate.provider,
        connectionId: candidate.connectionId ?? baseTarget.connectionId,
      };
      const factors = calculateFactors(
        candidate as ProviderCandidate,
        activeCandidates,
        taskType ?? "general",
        getTaskFitness,
        manifestHint ?? undefined
      );
      let score = calculateScore(factors, weights);
      // B17: Quota Share soft-policy deprioritization
      if ("quotaSoftPenalty" in candidate && candidate.quotaSoftPenalty === true) {
        score *= QUOTA_SOFT_DEPRIORITIZE_FACTOR;
      }
      // #4540: terminal/transient connection status soft penalty (no hard block).
      // A no-fetcher exhausted provider keeps quotaRemaining=100, so without this its
      // score would tie a healthy provider's. The penalty pushes it strictly below.
      if ("statusPenalty" in candidate && candidate.statusPenalty === true) {
        score *= STATUS_SOFT_DEPRIORITIZE_FACTOR;
      }
      return {
        target,
        score,
      };
    })
    .filter((entry): entry is { target: ResolvedComboTarget; score: number } => entry !== null)
    .sort((a, b) => b.score - a.score);
}

/**
 * For an auto-combo WITHOUT an explicit `candidatePool`, broaden the eligible
 * targets to every model of every active provider connection so the router has
 * the full pool to score over. Already-present `modelStr`s are not duplicated.
 *
 * Best-effort: if loading active connections or provider models throws, the
 * explicitly-resolved targets are returned unchanged (the combo still runs).
 * Exported for unit testing. Mutates and returns `eligibleTargets`.
 */
export async function expandAutoComboCandidatePool(
  eligibleTargets: ResolvedComboTarget[],
  combo: { autoConfig?: unknown; config?: unknown } | null | undefined
): Promise<ResolvedComboTarget[]> {
  const localAutoConfig =
    (combo?.autoConfig as Record<string, unknown> | undefined) ||
    (isRecord((combo?.config as Record<string, unknown>)?.auto)
      ? ((combo?.config as Record<string, unknown>).auto as Record<string, unknown>)
      : null) ||
    (combo?.config as Record<string, unknown> | undefined) ||
    {};

  if (Array.isArray(localAutoConfig?.candidatePool) && localAutoConfig.candidatePool.length > 0)
    return eligibleTargets;

  try {
    const allConnections = await getProviderConnections({ isActive: true });
    const providerIds = [
      ...new Set(
        (allConnections as Array<{ provider?: unknown }>)
          .map((c) => c.provider)
          .filter((p): p is string => typeof p === "string" && p.length > 0)
      ),
    ];
    for (const providerId of providerIds) {
      const providerModels = getProviderModels(providerId);
      for (const model of providerModels) {
        const modelStr = `${providerId}/${model.id}`;
        if (!eligibleTargets.some((t) => t.modelStr === modelStr)) {
          eligibleTargets.push({
            kind: "model",
            stepId: modelStr,
            executionKey: modelStr,
            provider: providerId,
            providerId: providerId,
            modelStr,
            weight: 1,
            connectionId: null,
            label: null,
          });
        }
      }
    }
  } catch {
    // Best-effort candidate expansion only: if loading active connections or
    // provider models fails, fall back to the explicitly-resolved targets
    // rather than aborting the combo. The push above is the only mutation,
    // so a throw leaves eligibleTargets exactly as explicit resolution built it.
  }

  return eligibleTargets;
}

/**
 * Derive a STABLE per-conversation session key for combo context-cache pinning when
 * the client did not provide an explicit session id (#3825).
 *
 * Most OpenAI-compatible clients send no session id, so the server-side pin added by
 * #3399 (gated on `relayOptions?.sessionId`) never engaged → combos rotated every turn,
 * causing upstream prompt-cache misses, cold high-reasoning starts and intermittent
 * 504s. We reuse `extractSessionAffinityKey(body)` (the same conversation fingerprint
 * used for codex failover affinity), which hashes the first user/system message — stable
 * across turns of the same conversation and identical on turn 2 of a continued chat.
 *
 * Returns null when no stable fingerprint is available (e.g. empty body), in which case
 * the caller falls back to NO pinning — preserving prior behavior rather than guessing.
 */
export function deriveComboSessionKey(body: Record<string, unknown>): string | null {
  try {
    return extractSessionAffinityKey(body) ?? null;
  } catch {
    return null;
  }
}