import { useCallback, useEffect, useMemo, useState } from "react";
import type { AppSnapshot } from "../../../types/domain";
import type { StoredScanResultEntry } from "../../../types/storage";
import {
  BUILD_FIT_PROFILE_CORPUS_VERSION,
  curatedBuildFitProfiles,
} from "../../../data/buildFitProfiles";
import {
  BUILD_FIT_COMBINATION_ASSESSMENT_VERSION,
  BUILD_FIT_CONTRACT_VERSION,
  BUILD_FIT_EVIDENCE_RANKING_VERSION,
  type BuildFitEvidenceRankingResultV1,
} from "../../../types/buildFit";
import {
  buildFitInputFromScanResult,
  rankBuildFitEvidence,
} from "../../../lib/buildFitContract";
import {
  aggregateContextKey,
  buildExplicitAggregateContexts,
  type BuildFitExplicitContextDraft,
} from "../../../lib/buildFitExplicitContext";
import { createRendererRepositories } from "../../../infrastructure/repositories/rendererBridgeRepositories";
import type { AppLocale } from "../../../i18n";
import { getBuildCopy } from "../buildsCopy";

const MAX_NATIVE_BUILD_FIT_RESULTS = 2400;

interface UseBuildsViewModelInput {
  snapshot: AppSnapshot;
  locale: AppLocale;
}

export interface BuildsViewModel {
  artifactCount: number;
  hasScanData: boolean;
  foundationLabel: string;
  foundationDetail: string;
  contractLabel: string;
  contractDetail: string;
  profileLabel: string;
  profileDetail: string;
  nativeRunDir: string;
  nativeResultCount: number;
  isLoadingBuildFit: boolean;
  buildFitLoadError: string;
  ranking: BuildFitEvidenceRankingResultV1;
  aggregateContextFields: BuildFitAggregateContextField[];
  setAggregateContextDraft: (
    profileId: string,
    targetKey: string,
    update: Partial<BuildFitExplicitContextDraft>,
  ) => void;
  refreshBuildFit: () => Promise<void>;
}

export interface BuildFitAggregateContextField {
  profileId: string;
  characterName: string;
  targetLabel: string;
  targetKey: string;
  stat: string;
  unit: "flat" | "percent";
  minimum?: number;
  maximum?: number;
  reason: string;
  value: string;
  confirmed: boolean;
  error: string;
}

export function useBuildsViewModel({ snapshot, locale }: UseBuildsViewModelInput): BuildsViewModel {
  const copy = getBuildCopy(locale);
  const repositories = useMemo(() => createRendererRepositories(), []);
  const [nativeResults, setNativeResults] = useState<StoredScanResultEntry[]>([]);
  const [nativeRunDir, setNativeRunDir] = useState("");
  const [nativeResultCount, setNativeResultCount] = useState(0);
  const [isLoadingBuildFit, setIsLoadingBuildFit] = useState(Boolean(repositories));
  const [buildFitLoadError, setBuildFitLoadError] = useState("");
  const [aggregateContextDrafts, setAggregateContextDrafts] = useState<Record<string, Record<string, BuildFitExplicitContextDraft>>>({});

  const refreshBuildFit = useCallback(async () => {
    if (!repositories?.automation) {
      setNativeResults([]);
      setNativeRunDir("");
      setNativeResultCount(0);
      setBuildFitLoadError(copy.noBridge);
      setIsLoadingBuildFit(false);
      return;
    }

    setIsLoadingBuildFit(true);
    setBuildFitLoadError("");
    try {
      const result = await repositories.automation.nativeScannerLoadResults({
        limit: MAX_NATIVE_BUILD_FIT_RESULTS,
      });
      if (!result.ok) {
        setNativeResults([]);
        setNativeRunDir("");
        setNativeResultCount(0);
        setBuildFitLoadError(result.error ?? copy.noCompleteRun);
        return;
      }
      setNativeResults(result.results);
      setNativeRunDir(result.runDir);
      setNativeResultCount(result.total);
    } catch (error) {
      setNativeResults([]);
      setNativeRunDir("");
      setNativeResultCount(0);
      setBuildFitLoadError(error instanceof Error ? error.message : copy.loadFailed);
    } finally {
      setIsLoadingBuildFit(false);
    }
  }, [copy.loadFailed, copy.noBridge, copy.noCompleteRun, repositories]);

  useEffect(() => {
    void refreshBuildFit();
  }, [refreshBuildFit]);

  const aggregateContextResults = useMemo(() => Object.fromEntries(
    curatedBuildFitProfiles.map((profile) => [
      profile.id,
      buildExplicitAggregateContexts(profile, aggregateContextDrafts[profile.id] ?? {}),
    ]),
  ) as Record<string, ReturnType<typeof buildExplicitAggregateContexts>>, [aggregateContextDrafts]);
  const aggregateContextByProfile = useMemo(() => Object.fromEntries(
    Object.entries(aggregateContextResults)
      .filter(([, result]) => result.contexts.length > 0)
      .map(([profileId, result]) => [profileId, result.contexts]),
  ), [aggregateContextResults]);
  const aggregateContextFields = useMemo(() => curatedBuildFitProfiles.flatMap((profile) => profile.aggregateTargets.map((target) => {
    const targetKey = aggregateContextKey(target);
    const draft = aggregateContextDrafts[profile.id]?.[targetKey] ?? { value: "", confirmed: false };
    return {
      profileId: profile.id,
      characterName: profile.character.name,
      targetLabel: profile.target.label,
      targetKey,
      stat: target.stat,
      unit: target.unit,
      ...(target.minimum === undefined ? {} : { minimum: target.minimum }),
      ...(target.maximum === undefined ? {} : { maximum: target.maximum }),
      reason: target.reason,
      value: draft.value,
      confirmed: draft.confirmed,
      error: aggregateContextResults[profile.id]?.issues[targetKey] ?? "",
    };
  })), [aggregateContextDrafts, aggregateContextResults]);
  const setAggregateContextDraft = useCallback((
    profileId: string,
    targetKey: string,
    update: Partial<BuildFitExplicitContextDraft>,
  ) => {
    setAggregateContextDrafts((current) => ({
      ...current,
      [profileId]: {
        ...current[profileId],
        [targetKey]: {
          value: current[profileId]?.[targetKey]?.value ?? "",
          confirmed: current[profileId]?.[targetKey]?.confirmed ?? false,
          ...update,
        },
      },
    }));
  }, []);

  const ranking = useMemo(() => rankBuildFitEvidence({
    version: BUILD_FIT_EVIDENCE_RANKING_VERSION,
    profiles: curatedBuildFitProfiles,
    artifacts: nativeResults
      .map((result) => buildFitInputFromScanResult(result))
      .filter((result): result is NonNullable<typeof result> => result !== null),
    aggregateContextByProfile,
  }), [aggregateContextByProfile, nativeResults]);
  const artifactCount = Math.max(snapshot.artifacts.length, nativeResultCount);
  const hasScanData = artifactCount > 0;
  const profileCount = curatedBuildFitProfiles.length;
  const suggestionCount = ranking.suggestions.length;

  return {
    artifactCount,
    hasScanData,
    foundationLabel: hasScanData ? copy.foundationReady : copy.foundationEmpty,
    foundationDetail: hasScanData
      ? copy.foundationReadyDetail(nativeResultCount || artifactCount)
      : copy.foundationEmptyDetail,
    contractLabel: copy.contractLabel,
    contractDetail: copy.contractDetail(
      BUILD_FIT_CONTRACT_VERSION,
      BUILD_FIT_COMBINATION_ASSESSMENT_VERSION,
      BUILD_FIT_EVIDENCE_RANKING_VERSION,
    ),
    profileLabel: suggestionCount > 0
      ? copy.profilesReady(suggestionCount)
      : copy.profilesChecked(profileCount),
    profileDetail: suggestionCount > 0
      ? copy.profilesReadyDetail(BUILD_FIT_PROFILE_CORPUS_VERSION)
      : copy.profilesBlockedDetail(BUILD_FIT_PROFILE_CORPUS_VERSION),
    nativeRunDir,
    nativeResultCount,
    isLoadingBuildFit,
    buildFitLoadError,
    ranking,
    aggregateContextFields,
    setAggregateContextDraft,
    refreshBuildFit,
  };
}