import { Injectable } from '@nestjs/common';
import { randomUUID } from 'node:crypto';
import { isDeepStrictEqual } from 'node:util';

import type {
  TbankInstrumentLookup as MetadataLookupRow,
  TbankInstrument as MetadataRow,
  Prisma,
} from '../../../generated/prisma/client';
import type { TbankInstrument } from './tbank.client';

import { PrismaService } from '../../prisma/prisma.service';
import { isJoinableRunningAttempt, type TbankSyncAttempt } from './tbank-access.service';
import { TbankErrorCode } from './tbank-error-code';
import { claimSyncWork, lockConnectionGeneration } from './tbank-sync-claim';

const FIRST_BATCH_OFFSET = 0;
const UNCHANGED_REVISION_INCREMENT = 0;
const REVISION_INCREMENT = 1;
const MISSING_DATA_REVISION = 0;

export type MetadataIdentity = {
  figi?: null | string;
  instrumentUid?: null | string;
};
export type MetadataLookup = {
  data: null | TbankInstrument;
  id: string;
  type: 'figi' | 'uid';
};
const provider = 'tbank';
// Keep IN lists below the SQLite/Prisma parameter limit, including fixed predicates.
const metadataReadBatchSize = 400;
export function metadataKey(identity: MetadataIdentity) {
  return JSON.stringify([
    identity.instrumentUid?.trim() || null,
    identity.figi?.trim() || null,
  ]);
}

@Injectable()
export class InstrumentMetadataRepository {
  constructor(private readonly prisma: PrismaService) {}

  async readMany(identities: MetadataIdentity[]) {
    const identifiers = identities.flatMap((identity) => [
      ...(identity.instrumentUid?.trim()
        ? [{ identifierType: 'uid', identifier: identity.instrumentUid.trim() }]
        : []),
      ...(identity.figi?.trim()
        ? [{ identifierType: 'figi', identifier: identity.figi.trim() }]
        : []),
    ]);
    if (!identifiers.length) {
      return new Map<string, ReturnType<typeof selectMetadata>>();
    }
    return this.prisma.$transaction(async (tx) => {
      const lookups: MetadataLookupRow[] = [];
      for (const identifierType of ['uid', 'figi']) {
        const values = [
          ...new Set(
            identifiers
              .filter((entry) => entry.identifierType === identifierType)
              .map((entry) => entry.identifier),
          ),
        ];
        for (
          let offset = FIRST_BATCH_OFFSET;
          offset < values.length;
          offset += metadataReadBatchSize
        ) {
          lookups.push(
            ...(await tx.tbankInstrumentLookup.findMany({
              where: {
                provider,
                identifierType,
                identifier: {
                  in: values.slice(offset, offset + metadataReadBatchSize),
                },
              },
            })),
          );
        }
      }
      const uids = [
        ...new Set(lookups.flatMap((row) => row.matchedUids as string[])),
      ];
      const instruments: MetadataRow[] = [];
      for (
        let offset = FIRST_BATCH_OFFSET;
        offset < uids.length;
        offset += metadataReadBatchSize
      ) {
        instruments.push(
          ...(await tx.tbankInstrument.findMany({
            where: {
              provider,
              uid: { in: uids.slice(offset, offset + metadataReadBatchSize) },
            },
          })),
        );
      }
      const byIdentifier = new Map(
        lookups.map((row) => [`${row.identifierType}:${row.identifier}`, row]),
      );
      const byUid = new Map(instruments.map((row) => [row.uid, row]));
      return new Map(
        identities.map((identity) => [
          metadataKey(identity),
          selectMetadata(identity, byIdentifier, byUid),
        ]),
      );
    });
  }

  async reserve(
    attemptOwner: { revision: string; userId: string },
    identity: MetadataIdentity,
    runId: string,
    active: ReadonlySet<string>,
  ) {
    return this.prisma.$transaction(async (tx) => {
      const valid = await lockConnectionGeneration(tx, attemptOwner);
      if (!valid) return null;
      const scope = {
        ...attemptOwner,
        scopeKey: `metadata:${metadataKey(identity)}`,
      };
      const previous = await tx.tbankSyncWork.findUnique({
        where: { userId_revision_scopeKey: scope },
      });
      if (isJoinableRunningAttempt(previous, runId, active)) {
        return { work: previous, launch: false };
      }
      const data = {
        attemptId: randomUUID(),
        processRunId: runId,
        state: 'running',
        priority: 1,
        intent: { source: 'metadata', ...identity },
        progress: {},
        errorCode: null,
      };
      const work = await tx.tbankSyncWork.upsert({
        where: { userId_revision_scopeKey: scope },
        create: { ...scope, ...data, id: randomUUID() },
        update: data,
      });
      return { work, launch: true };
    });
  }

  work(userId: string, revision: string, identity: MetadataIdentity) {
    return this.prisma.tbankSyncWork.findUnique({
      where: {
        userId_revision_scopeKey: {
          userId,
          revision,
          scopeKey: `metadata:${metadataKey(identity)}`,
        },
      },
      select: { id: true, state: true, errorCode: true },
    });
  }

  publish(attempt: TbankSyncAttempt, results: MetadataLookup[], now: Date) {
    return this.prisma.$transaction(async (tx) => {
      const claimed = await claimSyncWork(tx, attempt, {
        state: 'complete',
        progress: {},
      });
      if (!claimed) return false;
      const aliases = new Map(
        results.map((result) => [`${result.type}:${result.id}`, result]),
      );
      for (const result of results) {
        if (!result.data) continue;
        const uid =
          result.data.uid?.trim() || (result.type === 'uid' ? result.id : null);
        const figi =
          result.data.figi?.trim() ||
          (result.type === 'figi' ? result.id : null);
        for (const [type, id] of [
          ['uid', uid],
          ['figi', figi],
        ] as const) {
          if (id && uid && !aliases.has(`${type}:${id}`)) {
            aliases.set(`${type}:${id}`, {
              type,
              id,
              data: { ...result.data, uid },
            });
          }
        }
      }
      for (const result of aliases.values()) {
        const instrument = result.data;
        const uid =
          instrument?.uid?.trim() || (result.type === 'uid' ? result.id : null);
        // FIGI is an alias, never a fabricated provider UID.
        if (instrument && !uid) {
          throw new Error('Metadata response has no instrument UID');
        }
        if (instrument && uid) {
          const key = { provider, uid };
          const previous = await tx.tbankInstrument.findUnique({
            where: { provider_uid: key },
          });
          const payload = JSON.parse(
            JSON.stringify(instrument),
          ) as Prisma.InputJsonObject;
          const data = {
            metadata: payload,
            figi:
              instrument.figi ?? (result.type === 'figi' ? result.id : null),
            ticker: instrument.ticker ?? null,
            instrumentType: instrument.instrumentType ?? '',
            fetchedAt: now,
          };
          await tx.tbankInstrument.upsert({
            where: { provider_uid: key },
            create: { ...key, ...data },
            update: {
              ...data,
              dataRevision: {
                increment: isDeepStrictEqual(previous?.metadata, payload)
                  ? UNCHANGED_REVISION_INCREMENT
                  : REVISION_INCREMENT,
              },
            },
          });
        }
        const key = {
          provider,
          identifierType: result.type,
          identifier: result.id,
        };
        const matchedUids = instrument && uid ? [uid] : [];
        const previous = await tx.tbankInstrumentLookup.findUnique({
          where: { provider_identifierType_identifier: key },
        });
        await tx.tbankInstrumentLookup.upsert({
          where: { provider_identifierType_identifier: key },
          create: { ...key, matchedUids, fetchedAt: now },
          update: {
            matchedUids,
            fetchedAt: now,
            dataRevision: {
              increment: isDeepStrictEqual(previous?.matchedUids, matchedUids)
                ? UNCHANGED_REVISION_INCREMENT
                : REVISION_INCREMENT,
            },
          },
        });
      }
      return true;
    });
  }

  async finishObserver(attempt: TbankSyncAttempt, success: boolean) {
    await claimSyncWork(
      this.prisma,
      attempt,
      {
        state: success ? 'complete' : 'failed',
        errorCode: success ? null : TbankErrorCode.Unavailable,
      },
      { withoutConnectionFence: !success },
    );
    if (success) {
      // Fails sibling attempts whose connection was invalidated mid-flight.
      await this.prisma.tbankSyncWork.updateMany({
        where: {
          ...attempt,
          state: 'running',
          connection: { invalidToken: true },
        },
        data: { state: 'failed', errorCode: TbankErrorCode.InvalidToken },
      });
    }
  }
}

function selectMetadata(
  identity: MetadataIdentity,
  lookups: ReadonlyMap<string, MetadataLookupRow>,
  instruments: ReadonlyMap<string, MetadataRow>,
) {
  const resolve = (type: string, id: null | string | undefined) => {
    const lookup = lookups.get(`${type}:${id?.trim()}`);
    const uid = (lookup?.matchedUids as string[] | undefined)?.[0];
    const instrument = uid ? instruments.get(uid) : undefined;
    const data = instrument ? (instrument.metadata as TbankInstrument) : null;
    return { lookup, instrument, data };
  };
  const instrumentUid = identity.instrumentUid?.trim();
  const instrumentFigi = identity.figi?.trim();
  const uid = resolve('uid', instrumentUid);
  const figi = resolve('figi', instrumentFigi);
  const usefulUid = Boolean(uid.data?.name?.trim() || uid.data?.ticker?.trim());
  const used =
    usefulUid || !instrumentFigi ? [uid] : instrumentUid ? [uid, figi] : [figi];
  const complete = used.every((row) => Boolean(row.lookup));
  const fetchedAt =
    used
      .flatMap((row) => (row.lookup ? [row.lookup.fetchedAt] : []))
      .sort((a, b) => a.valueOf() - b.valueOf())[0] ?? null;
  return {
    data: usefulUid ? uid.data : (figi.data ?? uid.data),
    complete,
    fresh: complete,
    fetchedAt,
    dataRevision: used
      .map(
        (row) =>
          `${row.lookup?.dataRevision ?? MISSING_DATA_REVISION}:${row.instrument?.dataRevision ?? MISSING_DATA_REVISION}`,
      )
      .join('/'),
  };
}