import postgres, { createPool, PgDb, withTenant } from "./pg.ts";
import { config } from "./config.ts";
import { evaluateDocumentValidity, freshnessRequired, type ImssStatus, type WorkerImssContext } from "./document_validity.ts";

export type Db = PgDb;

/**
 * panels_product, esquema core: negocio (empresas, personal, obras,
 * expedientes, presupuesto, nómina, gafetes). Aislado de `iam` a propósito
 * -- este módulo no debe importar iam_db.ts.
 */

let corePool: postgres.Sql | null = null;
let coreOwnerPool: postgres.Sql | null = null;

function getCorePool(): postgres.Sql {
  if (!corePool) {
    corePool = createPool(config.databaseUrlCore, { max: 20 });
  }
  return corePool;
}

function getCoreOwnerPool(): postgres.Sql {
  if (!coreOwnerPool) {
    coreOwnerPool = createPool(config.databaseUrlCoreOwner || config.databaseUrlCore, { max: 3 });
  }
  return coreOwnerPool;
}

export async function pingCoreDb(): Promise<void> {
  await getCorePool()`SELECT 1`;
}

/** El único camino "normal" para atender un request: abre una transacción
 * con app.tenant_id fijado (Row Level Security), y la cierra sola al
 * terminar `fn` (commit) o al lanzar (rollback). Ver api/pg.ts#withTenant
 * y las políticas en db/core/changesets/005-rls.sql. */
export async function withCoreTenant<T>(
  tenantId: number | null,
  fn: (db: Db) => Promise<T>,
): Promise<T> {
  return await withTenant(getCorePool(), tenantId, fn);
}

/** Conexión SIN RLS (rol _owner, dueño de las tablas) -- reservada para
 * scripts (bootstrap, ETL) y para resoluciones internas puntuales que
 * necesitan cruzar tenants a propósito (ej. auth.ts al enriquecer el login
 * con el nombre de la empresa). NO usar en handlers de request normales. */
export async function getCoreDb(): Promise<Db> {
  return new PgDb(getCoreOwnerPool());
}

export async function closeCoreDb(): Promise<void> {
  await corePool?.end({ timeout: 5 });
  await coreOwnerPool?.end({ timeout: 5 });
  corePool = null;
  coreOwnerPool = null;
}

export async function lastInsertId(database: Db): Promise<number> {
  return await database.lastInsertId();
}

export const PROJECT_STATUSES = ["activo", "pausado", "concluido", "cancelado"] as const;
export type ProjectStatus = (typeof PROJECT_STATUSES)[number];

export const PROJECT_STATUS_CATALOG = [
  { code: "activo", label: "Activo" },
  { code: "pausado", label: "Pausado" },
  { code: "concluido", label: "Concluido" },
  { code: "cancelado", label: "Cancelado" },
] as const;

export function isProjectStatus(value: string): value is ProjectStatus {
  return (PROJECT_STATUSES as readonly string[]).includes(value);
}

export async function nextProjectCode(database: Db): Promise<string> {
  const row = await database.prepare(
    `SELECT COALESCE(MAX(substring(code from 5)::integer), 0) + 1 AS n
     FROM projects WHERE code ~ '^PRY-[0-9]{4}' OR code ~ '^OBR-[0-9]{4}'`,
  ).get() as { n: number };
  return `PRY-${String(row.n).padStart(4, "0")}`;
}

export async function projectById(database: Db, id: number) {
  return await database.prepare("SELECT * FROM projects WHERE id = ?").get(id) as
    | { id: number; code: string; name: string; status: string }
    | undefined;
}

export function projectMustBe(
  project: { status: string } | undefined,
  allowed: readonly ProjectStatus[],
  closedMessage: string,
): { error: string; status: 400 | 404 } | null {
  if (!project) return { error: "Proyecto no encontrado", status: 404 };
  if (!allowed.includes(project.status as ProjectStatus)) {
    return { error: closedMessage, status: 400 };
  }
  return null;
}

export async function workerImssContext(database: Db, workerId: number): Promise<WorkerImssContext> {
  const w = await database.prepare(
    "SELECT imss_status, imss_alta_at, last_rehire_at FROM workers WHERE id = ?",
  ).get(workerId) as {
    imss_status: ImssStatus;
    imss_alta_at: string | null;
    last_rehire_at: string | null;
  } | undefined;
  const altaDoc = await database.prepare(
    `SELECT imss_alta_at, uploaded_at FROM documents
     WHERE worker_id = ? AND type_code = 'alta_imss' AND is_current = true
     LIMIT 1`,
  ).get(workerId) as { imss_alta_at: string | null; uploaded_at: string } | undefined;
  return {
    imss_status: (w?.imss_status as ImssStatus) || "sin_alta",
    last_rehire_at: w?.last_rehire_at ?? null,
    current_alta_at: altaDoc?.imss_alta_at || w?.imss_alta_at || altaDoc?.uploaded_at || null,
  };
}

/** Checklist con vigencia; contexto IMSS vía imssFlagsFor / checklistItemsFor.
 * tenantId (Fase 4d) resuelve la zona horaria del tenant para calcular
 * "hoy" de forma consistente con nómina -- antes esta función usaba
 * `new Date()` crudo (hora del servidor/UTC) sin relación con PAYROLL_TZ. */
export async function checklistItemsFor(database: Db, workerId: number, tenantId: number | null = null) {
  const tz = await tenantTimezone(database, tenantId);
  const today = todayInTimezone(tz);
  const types = await database.prepare(
    `SELECT code, label, required, validity_mode, freshness_days,
      requires_issued_at, requires_expires_at, category
     FROM document_types`,
  ).all() as {
    code: string;
    label: string;
    required: boolean;
    validity_mode: string;
    freshness_days: number | null;
    requires_issued_at: boolean;
    requires_expires_at: boolean;
    category: string;
  }[];
  const currentDocs = await database.prepare(
    `SELECT type_code, issued_at, expires_at, uploaded_at, imss_alta_at
     FROM documents WHERE worker_id = ? AND is_current = true`,
  ).all(workerId) as {
    type_code: string;
    issued_at: string | null;
    expires_at: string | null;
    uploaded_at: string;
    imss_alta_at: string | null;
  }[];
  const byType = new Map(currentDocs.map((d) => [d.type_code, d]));
  const ctx = await workerImssContext(database, workerId);

  return {
    ctx,
    freshness_required: freshnessRequired(ctx),
    items: types.map((t) => {
      const policy = {
        code: t.code,
        label: t.label,
        required: !!t.required,
        validity_mode: (t.validity_mode || "none") as "none" | "freshness" | "expiry",
        freshness_days: t.freshness_days,
        requires_issued_at: !!t.requires_issued_at,
        requires_expires_at: !!t.requires_expires_at,
      };
      const evaled = evaluateDocumentValidity(policy, byType.get(t.code), ctx, today);
      return {
        code: t.code,
        label: t.label,
        required: !!t.required,
        validity_mode: policy.validity_mode,
        freshness_days: t.freshness_days,
        requires_issued_at: policy.requires_issued_at,
        requires_expires_at: policy.requires_expires_at,
        category: t.category || "otro",
        present: evaled.present,
        valid: evaled.valid,
        validity_status: evaled.validity_status,
        issued_at: evaled.issued_at,
        expires_at: evaled.expires_at,
      };
    }),
  };
}

export async function imssFlagsFor(database: Db, workerId: number, tenantId: number | null = null) {
  const { ctx, freshness_required: needFresh, items } = await checklistItemsFor(database, workerId, tenantId);
  const requiredOk = items.filter((i) => i.required).every((i) => i.present && i.valid);
  const inProject = !!await database.prepare(
    "SELECT 1 FROM assignments WHERE worker_id = ? AND active = true LIMIT 1",
  ).get(workerId);
  const hasImss = ctx.imss_status === "alta";
  return {
    imss_status: ctx.imss_status,
    freshness_required: needFresh,
    imss_ready: requiredOk && !hasImss,
    in_project_without_imss: inProject && !hasImss,
    expediente_ok: requiredOk,
  };
}

export async function checklistFor(database: Db, workerId: number, tenantId: number | null = null) {
  return (await checklistItemsFor(database, workerId, tenantId)).items;
}

export async function refreshPipeline(database: Db, workerId: number, tenantId: number | null = null): Promise<void> {
  const w = await database.prepare("SELECT status FROM workers WHERE id = ?").get(workerId) as
    | { status: string }
    | undefined;
  if (!w) return;
  if (w.status === "baja") {
    await database.prepare("UPDATE workers SET pipeline_status = 'baja' WHERE id = ?").run(workerId);
    return;
  }
  const items = await checklistFor(database, workerId, tenantId);
  const photo = items.find((i) => i.code === "foto");
  const photoOk = photo?.present && photo?.valid;
  const requiredOk = items.filter((i) => i.required).every((i) => i.present && i.valid);
  const printed = await database.prepare(
    `SELECT 1 FROM badge_job_people p
     JOIN badge_jobs j ON j.id = p.job_id
     WHERE p.worker_id = ? LIMIT 1`,
  ).get(workerId);
  let pipeline = "incompleto";
  if (requiredOk && photoOk) pipeline = printed ? "impreso" : "listo_gafete";
  const assigned = await database.prepare(
    "SELECT 1 FROM assignments WHERE worker_id = ? AND active = true LIMIT 1",
  ).get(workerId);
  if (pipeline !== "incompleto" && assigned) {
    pipeline = printed ? "activo" : "listo_gafete";
  }
  await database.prepare("UPDATE workers SET pipeline_status = ? WHERE id = ?").run(pipeline, workerId);
}

export async function projectChecklistFor(database: Db, projectId: number) {
  const types = await database.prepare(
    "SELECT code, label, required, category FROM project_document_types",
  ).all() as { code: string; label: string; required: boolean; category: string }[];
  const current = await database.prepare(
    `SELECT type_code FROM project_documents WHERE project_id = ? AND is_current = true`,
  ).all(projectId) as { type_code: string }[];
  const have = new Set(current.map((c) => c.type_code));
  return types.map((t) => ({
    code: t.code,
    label: t.label,
    required: !!t.required,
    category: t.category || "otro",
    present: have.has(t.code),
  }));
}

export async function companyChecklistFor(database: Db, companyId: number) {
  const types = await database.prepare(
    "SELECT code, label, required, category FROM company_document_types",
  ).all() as { code: string; label: string; required: boolean; category: string }[];
  const current = await database.prepare(
    `SELECT type_code FROM company_documents WHERE company_id = ? AND is_current = true`,
  ).all(companyId) as { type_code: string }[];
  const have = new Set(current.map((c) => c.type_code));
  return types.map((t) => ({
    code: t.code,
    label: t.label,
    required: !!t.required,
    category: t.category || "otro",
    present: have.has(t.code),
  }));
}

/** Zona horaria del tenant (Fase 4d) -- reemplaza el PAYROLL_TZ
 * hardcodeado. Con default sensato si el tenant no la configuró. */
export async function tenantTimezone(database: Db, tenantId: number | null): Promise<string> {
  if (tenantId == null) return "America/Mexico_City";
  const row = await database.prepare(
    "SELECT timezone FROM tenant_settings WHERE tenant_id = ?",
  ).get(tenantId) as { timezone: string } | undefined;
  return row?.timezone || "America/Mexico_City";
}

/** "Hoy" en la zona horaria del tenant, formato ISO (YYYY-MM-DD). Usado por
 * nómina y por validación de vigencia de documentos -- antes eran dos
 * nociones de "hoy" distintas (PAYROLL_TZ vs. new Date() crudo); ahora es
 * una sola función parametrizada por tenant. */
export function todayInTimezone(timezone: string, now = new Date()): string {
  return now.toLocaleDateString("en-CA", { timeZone: timezone });
}