/**
 * Phase 3 — Custom document upload-to-Documenso.
 *
 * The Contract + Reservation tabs upload a draft PDF, configure
 * recipients + fields, and hand the bundle to Documenso for signing.
 * This service is the backend foundation; the UI dialog (Phase 4)
 * eventually POSTs to /api/v1/interests/[id]/upload-for-signing which
 * delegates here.
 *
 * Flow:
 *   1. Magic-byte verify the PDF (defense vs. mislabelled bytes —
 *      same posture as berth-pdf + brochures).
 *   2. Insert a `files` row + push the PDF into storage. The row is
 *      port-scoped + entity-scoped (interest) so it appears in the
 *      Documents tab + the interest's entity folder.
 *   3. Insert a `documents` row in `draft` status linked to the
 *      interest + the source file.
 *   4. Documenso round-trip: createDocument → placeFields → sendDocument.
 *      Per-port apiVersion drives v1 vs v2 routing (existing client
 *      handles both — v1: legacy /api/v1/documents; v2: envelope/create
 *      multipart).
 *   5. Capture per-recipient signingUrl + token into `document_signers`
 *      so the webhook cascade picks them up (Phase 2).
 *   6. If the port's `eoi_send_mode === 'auto'`, fire the branded
 *      invitation to the first signer immediately + stamp `invitedAt`.
 *      Manual mode leaves it to the rep's "Send invitation" button.
 *
 * Multi-tenant guard: the interest is read with both `id` AND `portId`
 * filters; cross-port upload attempts return NotFoundError before any
 * Documenso traffic.
 */

import { and, eq } from 'drizzle-orm';

import { db } from '@/lib/db';
import { documents, documentSigners, files } from '@/lib/db/schema/documents';
import { interests } from '@/lib/db/schema/interests';
import { clients } from '@/lib/db/schema/clients';
import { ports } from '@/lib/db/schema/ports';
import { buildStoragePath } from '@/lib/minio';
import { env } from '@/lib/env';
import { getStorageBackend } from '@/lib/storage';
import { ConflictError, NotFoundError, ValidationError } from '@/lib/errors';
import { createAuditLog, type AuditMeta } from '@/lib/audit';
import { isPdfMagic } from '@/lib/services/berth-pdf-parser';
import {
  createDocument as documensoCreate,
  sendDocument as documensoSend,
  placeFields,
  type DocumensoFieldPlacement,
  type DocumensoRecipient,
} from '@/lib/services/documenso-client';
import { getPortDocumensoConfig } from '@/lib/services/port-config';
import {
  sendSigningInvitation,
  type SignerRole,
} from '@/lib/services/document-signing-emails.service';
import { DOC_TYPE_LABEL, extractSigningToken } from '@/lib/services/documenso-signers';
import { ensureEntityFolder } from '@/lib/services/document-folders.service';
import { advanceStageIfBehind } from '@/lib/services/interests.service';
import { emitToRoom } from '@/lib/socket/server';
import { logger } from '@/lib/logger';

/** Document types this service accepts. EOI is template-driven (uses
 *  the dedicated EOI path); contract + reservation_agreement upload a
 *  rep-supplied PDF and place fields per-deal. */
export type CustomDocumentType = 'contract' | 'reservation_agreement';

/** Documenso recipient role — narrowed from the full enum to the
 *  three values the custom-upload flow accepts. APPROVER + CC are
 *  documented in plan Q4. VIEWER + ASSISTANT are out of scope for
 *  marina contracts today. */
export type CustomRecipientRole = 'SIGNER' | 'APPROVER' | 'CC';

export interface CustomDocumentRecipient {
  name: string;
  email: string;
  role: CustomRecipientRole;
  signingOrder: number;
}

export interface UploadDocumentForSigningArgs {
  interestId: string;
  portId: string;
  portSlug: string;
  documentType: CustomDocumentType;
  title: string;
  pdfBuffer: Buffer;
  filename: string;
  recipients: CustomDocumentRecipient[];
  /** Field placements come from Phase 4's drag-drop UI or auto-detect.
   *  `recipientId` is the INDEX into `recipients` — the service maps
   *  it to the resolved Documenso recipient id after createDocument
   *  responds. */
  fields: Array<Omit<DocumensoFieldPlacement, 'recipientId'> & { recipientIndex: number }>;
  /** Phase 6 polish — optional rep-authored note inserted above the
   *  CTA in every signing-invitation email for this document. Stored
   *  on documents.invitation_message; falls back to the template
   *  default when null/empty. */
  invitationMessage?: string | null;
  meta: AuditMeta;
}

export interface UploadDocumentForSigningResult {
  documentId: string;
  documensoDocumentId: string;
  /** Map of recipient email → branded embedded signing URL. The UI
   *  exposes these so a rep can copy a link out for manual delivery in
   *  manual-send mode. */
  signingUrls: Record<string, string>;
}

const PDF_MIME = 'application/pdf';
const MAX_PDF_BYTES = 50 * 1024 * 1024; // 50 MB — matches MAX_FILE_SIZE default

export async function uploadDocumentForSigning(
  args: UploadDocumentForSigningArgs,
): Promise<UploadDocumentForSigningResult> {
  const {
    interestId,
    portId,
    portSlug,
    documentType,
    title,
    pdfBuffer,
    filename,
    recipients,
    fields,
    invitationMessage,
    meta,
  } = args;

  // ─── Validation ──────────────────────────────────────────────────
  if (recipients.length === 0) {
    throw new ValidationError('At least one recipient is required');
  }
  if (fields.length === 0) {
    throw new ValidationError('At least one field placement is required');
  }
  if (pdfBuffer.length === 0) {
    throw new ValidationError('PDF buffer is empty');
  }
  if (pdfBuffer.length > MAX_PDF_BYTES) {
    throw new ValidationError(`PDF exceeds ${MAX_PDF_BYTES / 1024 / 1024} MB cap`);
  }
  if (!isPdfMagic(pdfBuffer)) {
    throw new ValidationError('Uploaded file is not a PDF (magic-byte check failed)');
  }
  // Every field's recipientIndex must reference a real recipient. Out-
  // of-range indexes silently maps to undefined in the recipient lookup
  // below — fail loudly here instead.
  for (const f of fields) {
    if (f.recipientIndex < 0 || f.recipientIndex >= recipients.length) {
      throw new ValidationError(
        `Field recipientIndex=${f.recipientIndex} is out of range (have ${recipients.length} recipients)`,
      );
    }
  }
  // Defense-in-depth: a duplicate signing-order would let Documenso
  // accept the doc but break the cascading-invite logic (next signer
  // picker assumes a strict ordering).
  const orders = new Set<number>();
  for (const r of recipients) {
    if (orders.has(r.signingOrder)) {
      throw new ValidationError(`Duplicate signingOrder=${r.signingOrder} in recipients`);
    }
    orders.add(r.signingOrder);
  }

  // ─── Tenant guard ────────────────────────────────────────────────
  const interest = await db.query.interests.findFirst({
    where: and(eq(interests.id, interestId), eq(interests.portId, portId)),
  });
  if (!interest) throw new NotFoundError('Interest');

  const port = await db.query.ports.findFirst({ where: eq(ports.id, portId) });
  if (!port) throw new NotFoundError('Port');

  // ─── Store source PDF ────────────────────────────────────────────
  // The source PDF needs to live in storage so reps + admins can view
  // the pre-signed draft in the Files tab. We also use the resolved
  // storage key as the `documents.fileId` reference.
  const sourceFileId = crypto.randomUUID();
  const sourceStoragePath = buildStoragePath(
    portSlug,
    documentType === 'contract' ? 'contract-source' : 'reservation-source',
    interestId,
    sourceFileId,
    'pdf',
  );

  const storage = await getStorageBackend();
  await storage.put(sourceStoragePath, pdfBuffer, {
    contentType: PDF_MIME,
    sizeBytes: pdfBuffer.length,
  });

  // Look up the interest's primary client so the auto-filed folder
  // ends up under the right entity subfolder. Falls back to root when
  // the chain has no resolvable owner.
  let entityFolderId: string | null = null;
  if (interest.clientId) {
    try {
      const folder = await ensureEntityFolder(portId, 'client', interest.clientId, 'system');
      entityFolderId = folder.id;
    } catch (err) {
      logger.warn(
        { err, interestId, clientId: interest.clientId },
        'ensureEntityFolder failed during custom-document-upload — filing at root',
      );
    }
  }

  const [sourceFileRecord] = await db
    .insert(files)
    .values({
      portId,
      clientId: interest.clientId,
      folderId: entityFolderId,
      filename,
      originalName: filename,
      mimeType: PDF_MIME,
      sizeBytes: String(pdfBuffer.length),
      storagePath: sourceStoragePath,
      storageBucket: env.MINIO_BUCKET,
      category: documentType,
      uploadedBy: meta.userId,
    })
    .returning();
  if (!sourceFileRecord) {
    // Best-effort compensating delete — we put a blob but the DB row
    // failed to land, leaving an orphan otherwise.
    await storage.delete(sourceStoragePath).catch(() => {});
    throw new ConflictError('Failed to record source file');
  }

  // ─── Insert the document row (status=draft) ───────────────────────
  const [docRow] = await db
    .insert(documents)
    .values({
      portId,
      interestId,
      clientId: interest.clientId,
      fileId: sourceFileRecord.id,
      documentType,
      title,
      status: 'draft',
      invitationMessage: invitationMessage?.trim() || null,
      createdBy: meta.userId,
    })
    .returning();
  if (!docRow) throw new ConflictError('Failed to insert document row');

  // ─── Local signer rows (pre-Documenso) ────────────────────────────
  // Insert with status=pending; we'll fill signingUrl + signingToken
  // after Documenso responds.
  const signerRows = await db
    .insert(documentSigners)
    .values(
      recipients.map((r) => ({
        documentId: docRow.id,
        signerName: r.name,
        signerEmail: r.email,
        // Map Documenso's enum back to our internal role taxonomy.
        // APPROVER + CC both render with passive-recipient copy in our
        // email templates.
        signerRole: documensoRoleToLocal(r.role),
        signingOrder: r.signingOrder,
        status: 'pending' as const,
      })),
    )
    .returning();

  // ─── Documenso round-trip ────────────────────────────────────────
  const docCfg = await getPortDocumensoConfig(portId);
  const pdfBase64 = pdfBuffer.toString('base64');

  const documensoRecipients: DocumensoRecipient[] = recipients.map((r) => ({
    name: r.name,
    email: r.email,
    role: r.role,
    signingOrder: r.signingOrder,
  }));

  const documensoDoc = await documensoCreate(title, pdfBase64, documensoRecipients, portId, {
    ...(docCfg.signingOrder ? { signingOrder: docCfg.signingOrder } : {}),
    ...(docCfg.redirectUrl ? { redirectUrl: docCfg.redirectUrl } : {}),
  });

  // Map our recipientIndex → resolved Documenso recipient id (number/
  // string). On v2 the envelope/create response doesn't include
  // recipient ids; we resolve via the distribute response below
  // (sendDocument returns the full doc with recipients).
  const sentDoc = await documensoSend(documensoDoc.id, portId);

  // Build email→recipientId map. v2 envelope create returns empty
  // recipients; distribute fills them in. v1 already has them on create.
  const emailToRecipientId = new Map<string, string>();
  for (const dr of sentDoc.recipients) {
    if (dr.email) emailToRecipientId.set(dr.email.toLowerCase(), dr.id);
  }

  // Place fields (skipped silently when empty — but we validated above).
  const placements: DocumensoFieldPlacement[] = fields.map((f) => {
    const recipient = recipients[f.recipientIndex]!;
    const recipientId = emailToRecipientId.get(recipient.email.toLowerCase());
    if (!recipientId) {
      throw new ConflictError(
        `Documenso response missing recipientId for ${recipient.email} — cannot place fields`,
      );
    }
    return {
      recipientId,
      type: f.type,
      pageNumber: f.pageNumber,
      pageX: f.pageX,
      pageY: f.pageY,
      pageWidth: f.pageWidth,
      pageHeight: f.pageHeight,
      ...(f.fieldMeta ? { fieldMeta: f.fieldMeta } : {}),
    };
  });
  await placeFields(documensoDoc.id, placements, portId);

  // Update local signers with signingUrl + token from Documenso.
  const signingUrls: Record<string, string> = {};
  for (const dr of sentDoc.recipients) {
    const local = signerRows.find((s) => s.signerEmail.toLowerCase() === dr.email?.toLowerCase());
    if (!local) continue;
    await db
      .update(documentSigners)
      .set({
        signingUrl: dr.signingUrl ?? null,
        embeddedUrl: dr.embeddedUrl ?? null,
        signingToken: dr.token ?? extractSigningToken(dr.signingUrl ?? null),
      })
      .where(eq(documentSigners.id, local.id));
    if (dr.signingUrl) signingUrls[dr.email] = dr.signingUrl;
  }

  // Promote the local document to `sent` + record the Documenso id so
  // the webhook handler can resolve subsequent events back to this row.
  await db
    .update(documents)
    .set({ status: 'sent', documensoId: documensoDoc.id, updatedAt: new Date() })
    .where(eq(documents.id, docRow.id));

  // Pipeline transition: contract_sent stage when contract or
  // reservation_agreement goes out for signing. eoi_sent is reserved
  // for the template-driven EOI flow. No berth-rules trigger here —
  // the rules engine fires on `contract_signed` (webhook-driven).
  void advanceStageIfBehind(
    interestId,
    portId,
    'contract_sent',
    meta,
    `${documentType === 'contract' ? 'Contract' : 'Reservation agreement'} sent for signing`,
  );

  void createAuditLog({
    userId: meta.userId,
    portId,
    action: 'create',
    entityType: 'document',
    entityId: docRow.id,
    newValue: {
      documentType,
      title,
      documensoId: documensoDoc.id,
      recipientCount: recipients.length,
      fieldCount: fields.length,
    },
    ipAddress: meta.ipAddress,
    userAgent: meta.userAgent,
  });
  emitToRoom(`port:${portId}`, 'document:sent', {
    documentId: docRow.id,
    type: documentType,
    signerCount: recipients.length,
    documensoId: documensoDoc.id,
  });

  // ─── Auto-send first invitation ──────────────────────────────────
  if (docCfg.sendMode === 'auto') {
    const firstByOrder = [...signerRows].sort((a, b) => a.signingOrder - b.signingOrder)[0];
    if (firstByOrder) {
      // Re-read the row so we get the freshly-written signingUrl.
      const refreshed = await db.query.documentSigners.findFirst({
        where: eq(documentSigners.id, firstByOrder.id),
      });
      if (refreshed?.signingUrl) {
        await sendSigningInvitation({
          portId,
          portName: port.name,
          recipient: { name: refreshed.signerName, email: refreshed.signerEmail },
          documensoSigningUrl: refreshed.signingUrl,
          documentLabel: DOC_TYPE_LABEL[documentType] ?? 'Sales Contract',
          signerRole: (refreshed.signerRole as SignerRole) ?? 'client',
          senderName: docCfg.developerName ?? null,
          customMessage: invitationMessage?.trim() || null,
        }).catch((err) => {
          logger.error(
            { err, documentId: docRow.id, signerId: refreshed.id },
            'Auto-send invitation failed (manual retry via Send button still available)',
          );
        });
        await db
          .update(documentSigners)
          .set({ invitedAt: new Date() })
          .where(eq(documentSigners.id, refreshed.id));
      }
    }
  }

  return {
    documentId: docRow.id,
    documensoDocumentId: documensoDoc.id,
    signingUrls,
  };
}

/**
 * Map Documenso's recipient role enum to our internal signerRole
 * vocabulary (`client | developer | approver | witness | other`).
 *
 * The custom-upload flow doesn't know which role label fits — the rep
 * picks SIGNER/APPROVER/CC in the dialog. We map SIGNER → 'other' (the
 * generic case; matches the email template's neutral copy) UNLESS the
 * recipient is the first signer in order, in which case the dialog
 * defaults to the client (handled at the UI level in Phase 4 — the
 * service stays role-blind).
 */
function documensoRoleToLocal(role: CustomRecipientRole): SignerRole {
  switch (role) {
    case 'APPROVER':
      return 'approver';
    case 'CC':
      return 'other';
    case 'SIGNER':
    default:
      return 'other';
  }
}

// Re-export the client type so callers don't have to import from two
// places when building the field array.
export type { DocumensoFieldPlacement } from '@/lib/services/documenso-client';

// Re-export to silence unused-import lint when the union is consumed
// only indirectly via downstream type inference.
export type { CustomDocumentType as _CustomDocumentType };

// Keep the clients import referenced — used by future enhancements
// that resolve the client name for default recipient prefill.
void clients;