import { createHash } from 'node:crypto';
import type { AssessorRepository } from '../../src/persistence/assessor-repository';
import { RepositoryNotFoundError, RepositoryValidationError } from '../../src/persistence/repository-errors';
import { canonicalJson } from '../../src/shared/canonical-json';
import type { MicrosoftSecurityBaselineRecord } from '../../src/domain/microsoft-security-baseline';
import type { StoredMicrosoftSecurityBaselineAnalysis, MicrosoftSecurityBaselineSetting } from '../../src/domain/microsoft-security-baseline-analysis';
import type { AggregatedPolicyState, EnvironmentProfile, StoredPolicySnapshotAggregation } from '../../src/domain/gpo-snapshot-aggregation';
import {
  POLICY_COMPARATOR_CATALOG,
  POLICY_DEPENDENCY_RULESET,
  POLICY_EVALUATION_ENGINE,
  POLICY_RISK_RULESET,
  storedPolicyEvaluationValidationErrors,
  type CreatePolicyEvaluationRequest,
  type PolicyComparatorOutcome,
  type PolicyEvaluationEvidence,
  type PolicyEvaluationResult,
  type StoredPolicyEvaluation
} from '../../src/domain/policy-evaluation';
import { comparePolicyValues } from '../../src/evaluation/policy-comparator';
import { selectBaselineTemplates } from '../../src/evaluation/baseline-template-context';
import {
  RELEASED_POLICY_EVALUATION_RULE_CATALOG,
  policyEvaluationRuleCatalogValidationErrors,
  type PolicyEvaluationRuleCatalog
} from '../../src/domain/policy-evaluation-rules';

function stableId(prefix: string, value: string): string {
  return prefix + '-' + createHash('sha256').update(value).digest('hex').slice(0, 32);
}

function sortedUnique(values: string[]): string[] {
  return [...new Set(values)].sort((left, right) => left.localeCompare(right));
}

interface EvaluationBuildInput {
  profile: EnvironmentProfile;
  aggregation: StoredPolicySnapshotAggregation;
  baselineRecords: MicrosoftSecurityBaselineRecord[];
  baselineAnalyses: StoredMicrosoftSecurityBaselineAnalysis[];
  startedAt: string;
  completedAt: string;
  ruleCatalog: PolicyEvaluationRuleCatalog;
}

interface EvaluationEvidenceInput {
  kind: PolicyEvaluationEvidence['kind'];
  sourceIds: string[];
}

function evidenceFor(resultId: string, inputs: EvaluationEvidenceInput[]): PolicyEvaluationEvidence[] {
  return inputs.flatMap(input => sortedUnique(input.sourceIds).map(sourceId => ({
    version: 1 as const,
    id: stableId('policy-evaluation-evidence', resultId + '\0' + input.kind + '\0' + sourceId),
    evaluationResultId: resultId,
    kind: input.kind,
    sourceId
  })));
}

function evaluateBaselineIdentity(
  runId: string,
  analysis: StoredMicrosoftSecurityBaselineAnalysis,
  baseline: MicrosoftSecurityBaselineRecord,
  candidates: MicrosoftSecurityBaselineSetting[],
  state: AggregatedPolicyState | undefined,
  profile: EnvironmentProfile
): { result: PolicyEvaluationResult; evidence: PolicyEvaluationEvidence[] } {
  const diagnostics = new Set<string>();
  const selection = selectBaselineTemplates(candidates, profile);
  const settings = selection.settings;
  if (selection.status === 'selected') diagnostics.add('policy-evaluation-template-context-selected');
  if (selection.status === 'no-match') diagnostics.add('policy-evaluation-template-context-no-match');
  const identity = settings[0].identity.status === 'resolved' ? settings[0].identity.identity : undefined;
  if (!identity) throw new RepositoryValidationError('Eine Baselinegruppe besitzt keine aufgeloeste technische Identitaet.');
  if (analysis.analysis.status !== 'complete' || analysis.analysis.admxCatalog.status !== 'complete') {
    diagnostics.add('policy-evaluation-baseline-incomplete');
  }
  const recommendationSignatures = new Set(settings.map(setting => canonicalJson(setting.observation.values[0])));
  if (recommendationSignatures.size > 1) diagnostics.add('policy-evaluation-baseline-consensus-conflict');
  if (recommendationSignatures.size > 1 && selection.status === 'unresolved') {
    diagnostics.add('policy-evaluation-template-context-required');
  }
  const customerSignatures = new Set(state?.values.map(value => canonicalJson(value)) ?? []);
  if (state && customerSignatures.size !== 1) diagnostics.add('policy-evaluation-customer-value-ambiguous');
  const customerState: PolicyEvaluationResult['customerState'] = !state || state.status === 'deleted'
    ? 'missing'
    : state.status === 'conflicted' ? 'conflicted'
      : state.status === 'indeterminate' ? 'indeterminate' : 'configured';
  if (customerState === 'conflicted') diagnostics.add('policy-evaluation-customer-conflict');
  if (customerState === 'indeterminate') diagnostics.add('policy-evaluation-customer-state-incomplete');
  let compared: PolicyComparatorOutcome = {
    version: 1,
    comparator: { kind: 'equality' },
    relation: customerState === 'missing' ? 'different' : 'incomparable',
    baseline: undefined,
    diagnosticCodes: []
  };
  if (selection.status !== 'no-match' && recommendationSignatures.size === 1 && customerState === 'missing') {
    compared = comparePolicyValues(undefined, settings[0].observation.values[0], { kind: 'equality' });
    if (compared.baseline !== undefined) {
      compared = { ...compared, relation: 'different', diagnosticCodes: [] };
    } else {
      compared.diagnosticCodes.forEach(code => diagnostics.add(code));
    }
  } else if (selection.status !== 'no-match' && recommendationSignatures.size === 1 && customerState === 'configured' && customerSignatures.size === 1 && state) {
    compared = comparePolicyValues(state.values[0], settings[0].observation.values[0], { kind: 'equality' });
    compared.diagnosticCodes.forEach(code => diagnostics.add(code));
  }
  const review = selection.status === 'no-match' || recommendationSignatures.size !== 1 || ['conflicted', 'indeterminate'].includes(customerState)
    || compared.relation === 'incomparable';
  const classification: PolicyEvaluationResult['classification'] = review
    ? 'review_required'
    : compared.relation === 'match' ? 'configured_match' : 'confirmed_configured_deviation';
  const resultId = stableId('policy-evaluation-result', runId + '\0' + analysis.analysis.id + '\0' + identity.id);
  const baselineAnalysisIds = [analysis.analysis.id];
  const baselineSettingIds = sortedUnique(settings.map(setting => setting.id));
  const result: PolicyEvaluationResult = {
    version: 1,
    id: resultId,
    evaluationRunId: runId,
    aggregationStateId: customerState === 'missing' ? undefined : state?.id,
    baselineAnalysisId: analysis.analysis.id,
    baselineId: baseline.id,
    baselineLabel: baseline.fileName.replace(/\.zip$/i, ''),
    customerState,
    identity,
    classification,
    baselineState: compared.diagnosticCodes.length ? 'unsupported-setting' : 'explicit-recommendation',
    comparator: compared,
    ruleIds: [],
    dependencyRuleIds: [],
    riskRuleIds: [],
    contextIds: sortedUnique([...selection.contextIds, ...(state?.applicableContextIds ?? [])]),
    observationIds: customerState === 'missing' ? [] : sortedUnique(state?.observationIds ?? []),
    backupInstanceIds: customerState === 'missing' ? [] : sortedUnique(state?.backupInstanceIds ?? []),
    baselineAnalysisIds,
    baselineSettingIds,
    baselineTemplateSelection: { status: selection.status, contextIds: selection.contextIds,
      candidateSettingIds: sortedUnique(candidates.map(setting => setting.id)) },
    findingEligibility: 'ineligible',
    effectiveState: 'unknown',
    diagnosticCodes: [...diagnostics].sort()
  };
  return {
    result,
    evidence: evidenceFor(resultId, [
      { kind: 'customer-observation', sourceIds: result.observationIds },
      { kind: 'gpo-backup', sourceIds: result.backupInstanceIds },
      { kind: 'baseline-setting', sourceIds: result.baselineTemplateSelection!.candidateSettingIds },
      { kind: 'baseline-analysis', sourceIds: baselineAnalysisIds },
      { kind: 'environment-context', sourceIds: result.contextIds }
    ])
  };
}

export function buildPolicyEvaluation(input: EvaluationBuildInput): StoredPolicyEvaluation {
  const ruleCatalogErrors = policyEvaluationRuleCatalogValidationErrors(input.ruleCatalog);
  if (ruleCatalogErrors.length) throw new RepositoryValidationError(ruleCatalogErrors.join(' '));
  const baselineAnalysisIds = sortedUnique(input.baselineAnalyses.map(record => record.analysis.id));
  const runId = stableId('policy-evaluation-run', [
    input.profile.projectId,
    input.aggregation.run.id,
    POLICY_EVALUATION_ENGINE.version,
    POLICY_COMPARATOR_CATALOG.version,
    POLICY_DEPENDENCY_RULESET.version,
    POLICY_RISK_RULESET.version,
    canonicalJson(input.ruleCatalog),
    ...baselineAnalysisIds
  ].join('\0'));
  const statesByIdentity = new Map(input.aggregation.states.map(state => [state.identity.id, state]));
  const baselinesById = new Map(input.baselineRecords.map(record => [record.id, record]));
  const built = input.baselineAnalyses.flatMap(analysis => {
    const baseline = baselinesById.get(analysis.analysis.baselineId);
    if (!baseline) throw new RepositoryValidationError('Eine Baselineanalyse verweist auf keinen Baselinekatalogeintrag.');
    const grouped = new Map<string, MicrosoftSecurityBaselineSetting[]>();
    for (const setting of analysis.analysis.settings) {
      if (setting.identity.status !== 'resolved') continue;
      // A structurally parsed baseline row without an actual Microsoft
      // recommendation is not a benchmark and must not produce PASS/FAIL.
      if (setting.observation.values[0] === undefined) continue;
      const id = setting.identity.identity.id;
      grouped.set(id, [...(grouped.get(id) ?? []), setting]);
    }
    return [...grouped.entries()].sort(([left], [right]) => left.localeCompare(right))
      .map(([identityId, settings]) => evaluateBaselineIdentity(runId, analysis, baseline, settings, statesByIdentity.get(identityId), input.profile));
  });
  const results = built.map(item => item.result).sort((left, right) => left.id.localeCompare(right.id));
  const evidence = built.flatMap(item => item.evidence).sort((left, right) => left.id.localeCompare(right.id));
  const diagnostics = sortedUnique([
    ...input.aggregation.run.diagnosticCodes,
    ...results.flatMap(result => result.diagnosticCodes)
  ]);
  const blocked = input.aggregation.run.status === 'blocked';
  const partial = blocked || results.some(result => result.classification === 'review_required');
  const record: StoredPolicyEvaluation = {
    version: 1,
    run: {
      version: 1,
      id: runId,
      projectId: input.profile.projectId,
      aggregationRunId: input.aggregation.run.id,
      environmentProfileId: input.profile.id,
      baselineAnalysisIds,
      evaluator: POLICY_EVALUATION_ENGINE,
      comparatorCatalog: POLICY_COMPARATOR_CATALOG,
      ruleCatalog: input.ruleCatalog,
      dependencyRules: POLICY_DEPENDENCY_RULESET,
      riskRules: POLICY_RISK_RULESET,
      status: blocked ? 'blocked' : partial ? 'partial' : 'complete',
      resultCount: results.length,
      notApplicableCount: results.filter(result => result.classification === 'not_applicable').length,
      matchCount: results.filter(result => result.classification === 'configured_match').length,
      deviationCount: results.filter(result => result.classification === 'confirmed_configured_deviation').length,
      reviewCount: results.filter(result => result.classification === 'review_required').length,
      projectedFindingCount: 0,
      diagnosticCodes: diagnostics,
      startedAt: input.startedAt,
      completedAt: input.completedAt
    },
    results,
    evidence
  };
  const errors = storedPolicyEvaluationValidationErrors(record);
  if (errors.length) throw new RepositoryValidationError(errors.join(' '));
  return record;
}

export class GpoPolicyEvaluationService {
  private readonly now: () => Date;
  private readonly ruleCatalog: PolicyEvaluationRuleCatalog;

  constructor(private readonly repository: AssessorRepository, options: {
    now?: () => Date;
    ruleCatalog?: PolicyEvaluationRuleCatalog;
  } = {}) {
    this.now = options.now ?? (() => new Date());
    this.ruleCatalog = structuredClone(options.ruleCatalog ?? RELEASED_POLICY_EVALUATION_RULE_CATALOG);
    const errors = policyEvaluationRuleCatalogValidationErrors(this.ruleCatalog);
    if (errors.length) throw new RepositoryValidationError(errors.join(' '));
  }

  async evaluate(projectId: string, request: CreatePolicyEvaluationRequest): Promise<StoredPolicyEvaluation> {
    if (!request || typeof request.aggregationRunId !== 'string' || !request.aggregationRunId.trim()
      || !Array.isArray(request.baselineAnalysisIds)
      || request.baselineAnalysisIds.some(id => typeof id !== 'string' || !id.trim())) {
      throw new RepositoryValidationError('Die Policy-Evaluation-Anfrage ist ungueltig.');
    }
    const baselineAnalysisIds = sortedUnique(request.baselineAnalysisIds);
    if (!baselineAnalysisIds.length || baselineAnalysisIds.length !== request.baselineAnalysisIds.length) {
      throw new RepositoryValidationError('Mindestens ein eindeutiger Baseline-Analysis-Run ist erforderlich.');
    }
    const aggregation = (await this.repository.listPolicySnapshotAggregations(projectId))
      .find(record => record.run.id === request.aggregationRunId);
    if (!aggregation) throw new RepositoryNotFoundError('Der Policy-Snapshot-Aggregationslauf ist im Projekt nicht vorhanden.');
    const profile = (await this.repository.listEnvironmentProfiles(projectId))
      .find(record => record.id === aggregation.run.environmentProfileId);
    if (!profile) throw new RepositoryNotFoundError('Das Environment Profile des Aggregationslaufs ist nicht vorhanden.');
    const allAnalyses = await this.repository.listMicrosoftSecurityBaselineAnalyses();
    const analyses = baselineAnalysisIds.map(id => allAnalyses.find(record => record.analysis.id === id));
    if (analyses.some(record => !record)) throw new RepositoryNotFoundError('Mindestens eine Baselineanalyse ist nicht vorhanden.');
    const selected = analyses as StoredMicrosoftSecurityBaselineAnalysis[];
    const expectedId = stableId('policy-evaluation-run', [
      projectId, aggregation.run.id, POLICY_EVALUATION_ENGINE.version, POLICY_COMPARATOR_CATALOG.version,
      POLICY_DEPENDENCY_RULESET.version, POLICY_RISK_RULESET.version, canonicalJson(this.ruleCatalog),
      ...baselineAnalysisIds
    ].join('\0'));
    const existing = (await this.repository.listPolicyEvaluations(projectId)).find(record => record.run.id === expectedId);
    if (existing) return existing;
    const baselineRecords = await this.repository.listMicrosoftSecurityBaselines();
    const startedAt = this.now().toISOString();
    const record = buildPolicyEvaluation({
      profile,
      aggregation,
      baselineRecords,
      baselineAnalyses: selected,
      ruleCatalog: this.ruleCatalog,
      startedAt,
      completedAt: this.now().toISOString()
    });
    await this.repository.savePolicyEvaluation(record);
    return record;
  }

  list(projectId: string): Promise<StoredPolicyEvaluation[]> {
    return this.repository.listPolicyEvaluations(projectId);
  }
  catalog(): PolicyEvaluationRuleCatalog {
    return structuredClone(this.ruleCatalog);
  }
}