/**
 * Persistence + runner for aggregate reports.
 *
 * Spec: docs/ticket-analyzer-phase2-spec.md → Sections D.4–D.6
 */

import postgresClient from '@/lib/services/postgres-client';
import {
  type AggregateFingerprint,
  type AggregateReduceResponse,
  type AggregateReportStatus,
  type StageExecutionRecord,
} from '@/lib/types/analyzer';
import { getITGlueClient } from '@/lib/services/itglue-client';
import { runAggregateReduceStage } from './stages/aggregate-reduce';

interface AggregateReportRow {
  id: string;
  generated_by_user_id: string | null;
  generated_at: Date;
  filter_criteria: unknown;
  analysis_ids: string[];
  ticket_count: number;
  include_itglue_context: boolean;
  report_title: string | null;
  category_distribution: Record<string, number> | null;
  client_distribution: Record<string, number> | null;
  resolution_path_distribution: Record<string, number> | null;
  root_cause_distribution: Record<string, number> | null;
  date_range_actual: { earliest: string | null; latest: string | null } | null;
  documentation_gaps: unknown;
  process_gaps: unknown;
  client_patterns: unknown;
  recurrence_clusters: unknown;
  systemic_observations: unknown;
  recommended_actions: unknown;
  narrative_summary: string | null;
  executive_summary: string | null;
  total_input_tokens: number | null;
  total_output_tokens: number | null;
  estimated_cost_usd: string | null;
  model_used: string | null;
  itglue_context_included: boolean | null;
  status: AggregateReportStatus;
  error_message: string | null;
  expected_ticket_numbers: string[] | null;
  triggered_by_ticket_number: string | null;
}

export interface AggregateReportSummary {
  id: string;
  generatedByUserId: string | null;
  generatedAt: string;
  filterCriteria: unknown;
  analysisIds: string[];
  ticketCount: number;
  includeItglueContext: boolean;
  reportTitle: string | null;
  status: AggregateReportStatus;
  errorMessage: string | null;
  // SQL outputs
  categoryDistribution: Record<string, number> | null;
  clientDistribution: Record<string, number> | null;
  resolutionPathDistribution: Record<string, number> | null;
  rootCauseDistribution: Record<string, number> | null;
  dateRangeActual: { earliest: string | null; latest: string | null } | null;
  // LLM outputs
  documentationGaps: unknown;
  processGaps: unknown;
  clientPatterns: unknown;
  recurrenceClusters: unknown;
  systemicObservations: unknown;
  recommendedActions: unknown;
  narrativeSummary: string | null;
  executiveSummary: string | null;
  // Cost
  totalInputTokens: number | null;
  totalOutputTokens: number | null;
  estimatedCostUsd: number | null;
  modelUsed: string | null;
  // Bundle (Phase 3)
  expectedTicketNumbers: string[] | null;
  triggeredByTicketNumber: string | null;
}

function rowToSummary(r: AggregateReportRow): AggregateReportSummary {
  return {
    id: r.id,
    generatedByUserId: r.generated_by_user_id,
    generatedAt: r.generated_at.toISOString(),
    filterCriteria: r.filter_criteria,
    analysisIds: r.analysis_ids,
    ticketCount: r.ticket_count,
    includeItglueContext: r.include_itglue_context,
    reportTitle: r.report_title,
    status: r.status,
    errorMessage: r.error_message,
    categoryDistribution: r.category_distribution,
    clientDistribution: r.client_distribution,
    resolutionPathDistribution: r.resolution_path_distribution,
    rootCauseDistribution: r.root_cause_distribution,
    dateRangeActual: r.date_range_actual,
    documentationGaps: r.documentation_gaps,
    processGaps: r.process_gaps,
    clientPatterns: r.client_patterns,
    recurrenceClusters: r.recurrence_clusters,
    systemicObservations: r.systemic_observations,
    recommendedActions: r.recommended_actions,
    narrativeSummary: r.narrative_summary,
    executiveSummary: r.executive_summary,
    totalInputTokens: r.total_input_tokens,
    totalOutputTokens: r.total_output_tokens,
    estimatedCostUsd: r.estimated_cost_usd === null ? null : Number(r.estimated_cost_usd),
    modelUsed: r.model_used,
    expectedTicketNumbers: r.expected_ticket_numbers,
    triggeredByTicketNumber: r.triggered_by_ticket_number,
  };
}

const REPORT_SELECT = `
  id::text                              AS id,
  generated_by_user_id, generated_at,
  filter_criteria, analysis_ids::text[] AS analysis_ids,
  ticket_count, include_itglue_context, report_title,
  category_distribution, client_distribution, resolution_path_distribution,
  root_cause_distribution, date_range_actual,
  documentation_gaps, process_gaps, client_patterns, recurrence_clusters,
  systemic_observations, recommended_actions,
  narrative_summary, executive_summary,
  total_input_tokens, total_output_tokens,
  estimated_cost_usd::text              AS estimated_cost_usd,
  model_used, itglue_context_included,
  status, error_message,
  expected_ticket_numbers, triggered_by_ticket_number
`;

export interface CreateAggregateReportInput {
  generatedByUserId: string | null;
  filterCriteria: unknown;
  analysisIds: string[];
  ticketCount: number;
  includeItglueContext: boolean;
  reportTitle: string | null;
  /**
   * Bundle mode (Phase 3): when set, the report is created in the
   * 'pending_analyses' state and the worker will transition it to 'pending'
   * once every expected ticket has a complete analysis. Leave undefined for
   * the legacy manual-multi-select flow.
   */
  expectedTicketNumbers?: string[];
  triggeredByTicketNumber?: string;
}

export async function createAggregateReport(
  input: CreateAggregateReportInput
): Promise<{ id: string }> {
  const isBundle =
    Array.isArray(input.expectedTicketNumbers) &&
    input.expectedTicketNumbers.length > 0;
  const initialStatus = isBundle ? 'pending_analyses' : 'pending';
  const res = await postgresClient.query<{ id: string }>(
    `INSERT INTO analyzer_aggregate_reports
       (generated_by_user_id, filter_criteria, analysis_ids,
        ticket_count, include_itglue_context, report_title, status,
        expected_ticket_numbers, triggered_by_ticket_number)
     VALUES ($1, $2::jsonb, $3::uuid[], $4, $5, $6, $7, $8::text[], $9)
     RETURNING id::text AS id`,
    [
      input.generatedByUserId,
      JSON.stringify(input.filterCriteria),
      input.analysisIds,
      input.ticketCount,
      input.includeItglueContext,
      input.reportTitle,
      initialStatus,
      input.expectedTicketNumbers ?? null,
      input.triggeredByTicketNumber ?? null,
    ]
  );
  return { id: res.rows[0].id };
}

/**
 * Worker chain-trigger.
 *
 * Called after a single-ticket analysis completes successfully. For each
 * pending_analyses report waiting on this ticket: append the analysis_id (if
 * not already present), and if all expected tickets now have a complete
 * analysis, transition status='pending' and fire runAggregateReport.
 *
 * Idempotent: safe to invoke multiple times for the same analysis (the
 * deduplicating UPDATE skips no-ops; the status transition is gated on the
 * full set being present so the second call is a no-op).
 */
export async function chainTriggerForCompletedAnalysis(
  ticketNumber: string,
  analysisId: string
): Promise<{ readyReportIds: string[]; touchedReportIds: string[] }> {
  const res = await postgresClient.query<{
    id: string;
    expected_ticket_numbers: string[];
    analysis_ids: string[];
  }>(
    `SELECT id::text AS id,
            expected_ticket_numbers,
            analysis_ids::text[] AS analysis_ids
       FROM analyzer_aggregate_reports
      WHERE status = 'pending_analyses'
        AND expected_ticket_numbers @> ARRAY[$1]::text[]`,
    [ticketNumber]
  );

  const touched: string[] = [];
  const ready: string[] = [];

  for (const r of res.rows) {
    if (!r.analysis_ids.includes(analysisId)) {
      await postgresClient.query(
        `UPDATE analyzer_aggregate_reports
            SET analysis_ids = analysis_ids || $2::uuid
          WHERE id = $1
            AND NOT (analysis_ids @> ARRAY[$2::uuid])`,
        [r.id, analysisId]
      );
      touched.push(r.id);
    }

    // Re-check whether the full set is now satisfied: every expected ticket
    // must have at least one complete analysis whose id is in analysis_ids.
    // Reads the latest analysis_ids (the UPDATE above isn't reflected in the
    // copy we loaded earlier).
    const ready_check = await postgresClient.query<{ satisfied: boolean }>(
      `SELECT (
         (SELECT COUNT(DISTINCT aa.ticket_number)
            FROM analyzer_analyses aa
            JOIN analyzer_aggregate_reports r ON r.id = $1
           WHERE aa.id = ANY(r.analysis_ids)
             AND aa.status = 'complete'
             AND aa.ticket_number = ANY(r.expected_ticket_numbers))
         =
         (SELECT array_length(expected_ticket_numbers, 1)
            FROM analyzer_aggregate_reports WHERE id = $1)
       ) AS satisfied`,
      [r.id]
    );

    if (ready_check.rows[0]?.satisfied) {
      const transition = await postgresClient.query<{ id: string }>(
        `UPDATE analyzer_aggregate_reports
            SET status = 'pending'
          WHERE id = $1
            AND status = 'pending_analyses'
          RETURNING id::text AS id`,
        [r.id]
      );
      if (transition.rowCount && transition.rowCount > 0) {
        ready.push(r.id);
      }
    }
  }

  return { readyReportIds: ready, touchedReportIds: touched };
}

export async function getAggregateReport(
  id: string
): Promise<AggregateReportSummary | null> {
  const res = await postgresClient.query<AggregateReportRow>(
    `SELECT ${REPORT_SELECT} FROM analyzer_aggregate_reports WHERE id = $1`,
    [id]
  );
  if (res.rowCount === 0) return null;
  return rowToSummary(res.rows[0]);
}

export async function listAggregateReports(opts: {
  limit?: number;
  offset?: number;
  generatedByUserId?: string;
}): Promise<AggregateReportSummary[]> {
  const limit = Math.min(opts.limit ?? 50, 200);
  const offset = opts.offset ?? 0;
  const params: unknown[] = [limit, offset];
  let userClause = '';
  if (opts.generatedByUserId) {
    params.push(opts.generatedByUserId);
    userClause = `WHERE generated_by_user_id = $${params.length}`;
  }
  const res = await postgresClient.query<AggregateReportRow>(
    `SELECT ${REPORT_SELECT}
       FROM analyzer_aggregate_reports
       ${userClause}
      ORDER BY generated_at DESC
      LIMIT $1 OFFSET $2`,
    params
  );
  return res.rows.map(rowToSummary);
}

interface FingerprintRow {
  id: string;
  ticket_number: string;
  aggregate_fingerprint: AggregateFingerprint;
  triggered_at: Date;
}

async function loadFingerprints(
  analysisIds: string[]
): Promise<{ ticket_number: string; fingerprint: AggregateFingerprint; triggered_at: Date }[]> {
  if (analysisIds.length === 0) return [];
  const res = await postgresClient.query<FingerprintRow>(
    `SELECT id::text AS id, ticket_number, aggregate_fingerprint, triggered_at
       FROM analyzer_analyses
      WHERE id = ANY($1::uuid[])
        AND aggregate_fingerprint IS NOT NULL
      ORDER BY ticket_number, analysis_version DESC`,
    [analysisIds]
  );
  return res.rows.map((r) => ({
    ticket_number: r.ticket_number,
    fingerprint: r.aggregate_fingerprint,
    triggered_at: r.triggered_at,
  }));
}

function bucketCount(items: string[]): Record<string, number> {
  const out: Record<string, number> = {};
  for (const i of items) out[i] = (out[i] ?? 0) + 1;
  return out;
}

async function fetchITGlueDocTitles(
  clientNames: string[]
): Promise<{ client_name: string; doc_titles: string[] }[]> {
  let client;
  try {
    client = getITGlueClient();
  } catch {
    return []; // not configured — caller should fall back gracefully
  }
  const result: { client_name: string; doc_titles: string[] }[] = [];
  for (const name of clientNames) {
    try {
      const org = await client.findOrganizationByName(name);
      if (!org) continue;
      const docs = await client.getFlexibleAssetsForOrganization(org.id);
      const titles = docs
        .map((d) => (d as { name?: string }).name)
        .filter((t): t is string => typeof t === 'string')
        .slice(0, 50);
      result.push({ client_name: name, doc_titles: titles });
    } catch {
      // Tolerate per-client failures.
    }
  }
  return result;
}

const ITGLUE_DOC_TITLE_CAP = 200;

export async function bulkInsertReportStageExecutions(
  reportId: string,
  records: StageExecutionRecord[]
): Promise<void> {
  if (records.length === 0) return;
  const values: unknown[] = [reportId];
  const tuples: string[] = [];
  for (const r of records) {
    const base = values.length;
    values.push(
      r.stage,
      r.stage_order,
      r.model_id,
      JSON.stringify(r.input_payload ?? {}),
      JSON.stringify(r.output_payload ?? {}),
      r.input_tokens,
      r.output_tokens,
      r.latency_ms,
      r.started_at,
      r.completed_at,
      r.error_message
    );
    tuples.push(
      `($1, $${base + 1}, $${base + 2}, $${base + 3}, $${base + 4}::jsonb, ` +
        `$${base + 5}::jsonb, $${base + 6}, $${base + 7}, $${base + 8}, ` +
        `$${base + 9}, $${base + 10}, $${base + 11})`
    );
  }
  await postgresClient.query(
    `INSERT INTO analyzer_stage_executions
       (aggregate_report_id, stage, stage_order, model_id,
        input_payload, output_payload,
        input_tokens, output_tokens, latency_ms,
        started_at, completed_at, error_message)
     VALUES ${tuples.join(', ')}`,
    values
  );
}

/**
 * Fire-and-forget runner. Intended to be invoked from the POST endpoint with
 * `void runAggregateReport(id)` — the route returns immediately, this updates
 * the row when work completes (or fails).
 */
export async function runAggregateReport(reportId: string): Promise<void> {
  const stageRecords: StageExecutionRecord[] = [];
  try {
    await postgresClient.query(
      `UPDATE analyzer_aggregate_reports SET status = 'running' WHERE id = $1`,
      [reportId]
    );

    const report = await getAggregateReport(reportId);
    if (!report) throw new Error('report row vanished');

    // ── Step 1: load fingerprints + compute SQL distributions ──
    const sqlStart = new Date();
    const fingerprints = await loadFingerprints(report.analysisIds);
    if (fingerprints.length === 0) {
      throw new Error('no analyses with fingerprints found for the given IDs');
    }
    const categories = bucketCount(fingerprints.map((f) => f.fingerprint.category));
    const clients = bucketCount(fingerprints.map((f) => f.fingerprint.client_name));
    const resolutionPaths = bucketCount(
      fingerprints.map((f) => f.fingerprint.resolution_path)
    );
    const rootCauses = bucketCount(
      fingerprints.map((f) => f.fingerprint.root_cause_class)
    );
    const dates = fingerprints.map((f) => f.triggered_at.getTime());
    const dateRange = {
      earliest: new Date(Math.min(...dates)).toISOString(),
      latest: new Date(Math.max(...dates)).toISOString(),
    };
    const sqlEnd = new Date();
    stageRecords.push({
      stage: 'analyze', // Reusing 'analyze' since CHECK constraint enumerates only stage names; a future migration could add 'aggregate_sql' / 'aggregate_reduce'.
      stage_order: 1,
      model_id: null,
      input_payload: { analysis_ids: report.analysisIds },
      output_payload: {
        category_distribution: categories,
        client_distribution: clients,
        resolution_path_distribution: resolutionPaths,
        root_cause_distribution: rootCauses,
        date_range_actual: dateRange,
        fingerprint_count: fingerprints.length,
      },
      input_tokens: null,
      output_tokens: null,
      latency_ms: sqlEnd.getTime() - sqlStart.getTime(),
      started_at: sqlStart,
      completed_at: sqlEnd,
      error_message: null,
    });

    // Persist partial results immediately so UI can show distributions.
    await postgresClient.query(
      `UPDATE analyzer_aggregate_reports
          SET category_distribution = $2::jsonb,
              client_distribution = $3::jsonb,
              resolution_path_distribution = $4::jsonb,
              root_cause_distribution = $5::jsonb,
              date_range_actual = $6::jsonb
        WHERE id = $1`,
      [
        reportId,
        JSON.stringify(categories),
        JSON.stringify(clients),
        JSON.stringify(resolutionPaths),
        JSON.stringify(rootCauses),
        JSON.stringify(dateRange),
      ]
    );

    // ── Step 2: IT Glue context (optional) ──
    let itglueDocTitles: { client_name: string; doc_titles: string[] }[] | undefined;
    let itglueIncluded = false;
    if (report.includeItglueContext) {
      const uniqueClients = Array.from(
        new Set(fingerprints.map((f) => f.fingerprint.client_name))
      );
      const itglueStart = new Date();
      itglueDocTitles = await fetchITGlueDocTitles(uniqueClients);
      // Cap to spec total (200 doc titles across all clients).
      let remaining = ITGLUE_DOC_TITLE_CAP;
      itglueDocTitles = itglueDocTitles.map((c) => {
        if (remaining <= 0) return { client_name: c.client_name, doc_titles: [] };
        const titles = c.doc_titles.slice(0, remaining);
        remaining -= titles.length;
        return { client_name: c.client_name, doc_titles: titles };
      });
      itglueIncluded = itglueDocTitles.some((c) => c.doc_titles.length > 0);
      const itglueEnd = new Date();
      stageRecords.push({
        stage: 'itglue',
        stage_order: 2,
        model_id: null,
        input_payload: { client_count: uniqueClients.length },
        output_payload: { doc_count: itglueDocTitles.reduce((a, c) => a + c.doc_titles.length, 0) },
        input_tokens: null,
        output_tokens: null,
        latency_ms: itglueEnd.getTime() - itglueStart.getTime(),
        started_at: itglueStart,
        completed_at: itglueEnd,
        error_message: null,
      });
    }

    // ── Step 3: reduce LLM call ──
    // Honour the provider the bundle was created with. Manual aggregate reports
    // (no provider in filter_criteria) default to anthropic.
    const reduceProvider: 'anthropic' | 'openrouter' =
      (report.filterCriteria as { provider?: string } | null)?.provider === 'openrouter'
        ? 'openrouter'
        : 'anthropic';
    const reduceStart = new Date();
    let reduceResult;
    try {
      reduceResult = await runAggregateReduceStage(
        {
          distributions: {
            category_distribution: categories,
            client_distribution: clients,
            resolution_path_distribution: resolutionPaths,
            root_cause_distribution: rootCauses,
            date_range_actual: dateRange,
          },
          fingerprints: fingerprints.map((f) => ({
            ticket_number: f.ticket_number,
            fingerprint: f.fingerprint,
          })),
          itglue_doc_titles: itglueDocTitles,
        },
        { provider: reduceProvider }
      );
    } catch (err) {
      const reduceEnd = new Date();
      stageRecords.push({
        stage: 'analyze',
        stage_order: 3,
        model_id: null,
        input_payload: { fingerprint_count: fingerprints.length },
        output_payload: {},
        input_tokens: null,
        output_tokens: null,
        latency_ms: reduceEnd.getTime() - reduceStart.getTime(),
        started_at: reduceStart,
        completed_at: reduceEnd,
        error_message: err instanceof Error ? err.message : String(err),
      });
      throw err;
    }
    const reduceEnd = new Date();
    stageRecords.push({
      stage: 'analyze',
      stage_order: 3,
      model_id: reduceResult.model_used,
      input_payload: { fingerprint_count: fingerprints.length },
      output_payload: reduceResult.data,
      input_tokens: reduceResult.usage.input_tokens,
      output_tokens: reduceResult.usage.output_tokens,
      latency_ms: reduceEnd.getTime() - reduceStart.getTime(),
      started_at: reduceStart,
      completed_at: reduceEnd,
      error_message: null,
    });

    // ── Step 4: persist outputs ──
    await postgresClient.query(
      `UPDATE analyzer_aggregate_reports
          SET documentation_gaps = $2::jsonb,
              process_gaps = $3::jsonb,
              client_patterns = $4::jsonb,
              recurrence_clusters = $5::jsonb,
              systemic_observations = $6::jsonb,
              recommended_actions = $7::jsonb,
              narrative_summary = $8,
              executive_summary = $9,
              total_input_tokens = $10,
              total_output_tokens = $11,
              estimated_cost_usd = $12,
              model_used = $13,
              itglue_context_included = $14,
              status = 'complete'
        WHERE id = $1`,
      [
        reportId,
        JSON.stringify(reduceResult.data.documentation_gaps),
        JSON.stringify(reduceResult.data.process_gaps),
        JSON.stringify(reduceResult.data.client_patterns),
        JSON.stringify(reduceResult.data.recurrence_clusters),
        JSON.stringify(reduceResult.data.systemic_observations),
        JSON.stringify(reduceResult.data.recommended_actions),
        reduceResult.data.narrative_summary,
        reduceResult.data.executive_summary,
        reduceResult.usage.input_tokens,
        reduceResult.usage.output_tokens,
        reduceResult.estimated_cost_usd,
        reduceResult.model_used,
        itglueIncluded,
      ]
    );

    await bulkInsertReportStageExecutions(reportId, stageRecords);
  } catch (err) {
    const message = err instanceof Error ? err.message : String(err);
    console.error(`[ANALYZER-REPORT] runAggregateReport ${reportId} failed:`, message);
    await postgresClient
      .query(
        `UPDATE analyzer_aggregate_reports
            SET status = 'failed', error_message = $2
          WHERE id = $1`,
        [reportId, message]
      )
      .catch(() => {});
    if (stageRecords.length > 0) {
      await bulkInsertReportStageExecutions(reportId, stageRecords).catch(() => {});
    }
  }
}