const db = require('../../config/db');

const ensureSchema = async () => {
  await db.execute(`
    CREATE TABLE IF NOT EXISTS invitation_flows (
      id INT AUTO_INCREMENT PRIMARY KEY,
      document_id INT NOT NULL,
      owner_user_id INT NOT NULL,
      base_signature_id INT NOT NULL,
      status VARCHAR(32) NOT NULL DEFAULT 'active',
      current_signed_filename VARCHAR(255) NOT NULL,
      current_signed_path VARCHAR(500) NOT NULL,
      signature_style VARCHAR(32) NOT NULL DEFAULT 'qr',
      qr_position VARCHAR(16) NULL,
      qr_background VARCHAR(16) NULL,
      qr_border VARCHAR(16) NULL,
      signature_image_base64 MEDIUMTEXT NULL,
      total_invites INT NOT NULL DEFAULT 0,
      completed_invites INT NOT NULL DEFAULT 0,
      created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
      updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
      INDEX idx_invitation_flows_document_owner (document_id, owner_user_id),
      INDEX idx_invitation_flows_status (status)
    )
  `);

  await db.execute(`
    CREATE TABLE IF NOT EXISTS invitation_signers (
      id INT AUTO_INCREMENT PRIMARY KEY,
      flow_id INT NOT NULL,
      owner_user_id INT NOT NULL,
      document_id INT NOT NULL,
      order_index INT NOT NULL,
      invitee_name VARCHAR(160) NOT NULL,
      invitee_email VARCHAR(255) NOT NULL,
      token VARCHAR(255) NOT NULL,
      token_expires DATETIME NOT NULL,
      status VARCHAR(32) NOT NULL DEFAULT 'queued',
      legal_accepted_at DATETIME NULL,
      viewed_at DATETIME NULL,
      sent_at DATETIME NULL,
      signed_at DATETIME NULL,
      signed_filename VARCHAR(255) NULL,
      signed_path VARCHAR(500) NULL,
      certificate_subject_cn VARCHAR(255) NULL,
      certificate_issuer_cn VARCHAR(255) NULL,
      verification_code VARCHAR(100) NULL,
      verification_url VARCHAR(500) NULL,
      created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
      updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
      UNIQUE KEY uq_invitation_signers_token (token),
      UNIQUE KEY uq_invitation_signers_flow_order (flow_id, order_index),
      INDEX idx_invitation_signers_document_owner (document_id, owner_user_id),
      INDEX idx_invitation_signers_status (status)
    )
  `);
};

const createFlow = async ({
  documentId,
  ownerUserId,
  baseSignatureId,
  currentSignedFilename,
  currentSignedPath,
  signatureStyle,
  qrPosition,
  qrBackground,
  qrBorder,
  signatureImageBase64,
  totalInvites,
}) => {
  const [result] = await db.execute(
    `INSERT INTO invitation_flows
      (document_id, owner_user_id, base_signature_id, current_signed_filename, current_signed_path,
       signature_style, qr_position, qr_background, qr_border, signature_image_base64, total_invites)
     VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
    [
      documentId,
      ownerUserId,
      baseSignatureId,
      currentSignedFilename,
      currentSignedPath,
      signatureStyle,
      qrPosition || null,
      qrBackground || null,
      qrBorder || null,
      signatureImageBase64 || null,
      totalInvites,
    ]
  );
  return result.insertId;
};

const createInvitation = async ({
  flowId,
  ownerUserId,
  documentId,
  orderIndex,
  inviteeName,
  inviteeEmail,
  token,
  tokenExpires,
  status,
}) => {
  const [result] = await db.execute(
    `INSERT INTO invitation_signers
      (flow_id, owner_user_id, document_id, order_index, invitee_name, invitee_email, token, token_expires, status)
     VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`,
    [flowId, ownerUserId, documentId, orderIndex, inviteeName, inviteeEmail, token, tokenExpires, status]
  );
  return result.insertId;
};

const findFlowByDocumentOwner = async (documentId, ownerUserId) => {
  const [rows] = await db.execute(
    'SELECT * FROM invitation_flows WHERE document_id = ? AND owner_user_id = ? ORDER BY id DESC LIMIT 1',
    [documentId, ownerUserId]
  );
  return rows[0] || null;
};

const findFlowById = async (id) => {
  const [rows] = await db.execute('SELECT * FROM invitation_flows WHERE id = ?', [id]);
  return rows[0] || null;
};

const listInvitationsByFlow = async (flowId) => {
  const [rows] = await db.execute(
    'SELECT * FROM invitation_signers WHERE flow_id = ? ORDER BY order_index ASC',
    [flowId]
  );
  return rows;
};

const getMaxOrderIndex = async (flowId) => {
  const [rows] = await db.execute(
    `SELECT COALESCE(MAX(order_index), 0) AS maxOrder
     FROM invitation_signers
     WHERE flow_id = ?`,
    [flowId]
  );
  return Number(rows[0]?.maxOrder || 0);
};

const findInvitationByIdForOwner = async (id, ownerUserId) => {
  const [rows] = await db.execute(
    `SELECT i.*, f.status as flow_status, f.current_signed_filename, f.current_signed_path,
            f.signature_style, f.qr_position, f.qr_background, f.qr_border, f.signature_image_base64,
            f.base_signature_id, f.total_invites, f.completed_invites,
            d.title as document_title, d.filename as document_filename,
            u.name as owner_name, u.email as owner_email
     FROM invitation_signers i
     JOIN invitation_flows f ON f.id = i.flow_id
     JOIN documents d ON d.id = i.document_id
     JOIN users u ON u.id = i.owner_user_id
     WHERE i.id = ? AND i.owner_user_id = ?
     LIMIT 1`,
    [id, ownerUserId]
  );
  return rows[0] || null;
};

const findInvitationByToken = async (token) => {
  const [rows] = await db.execute(
    `SELECT i.*, f.status as flow_status, f.current_signed_filename, f.current_signed_path,
            f.signature_style, f.qr_position, f.qr_background, f.qr_border, f.signature_image_base64,
            f.base_signature_id, f.total_invites, f.completed_invites,
            d.title as document_title, d.filename as document_filename,
            u.name as owner_name, u.email as owner_email
     FROM invitation_signers i
     JOIN invitation_flows f ON f.id = i.flow_id
     JOIN documents d ON d.id = i.document_id
     JOIN users u ON u.id = i.owner_user_id
     WHERE i.token = ?
     LIMIT 1`,
    [token]
  );
  return rows[0] || null;
};

const markInvitationSent = async (id) => {
  await db.execute(
    `UPDATE invitation_signers
     SET status = 'sent',
         sent_at = COALESCE(sent_at, NOW())
     WHERE id = ?`,
    [id]
  );
};

const markInvitationViewed = async (id) => {
  await db.execute(
    `UPDATE invitation_signers
     SET status = CASE WHEN status = 'sent' THEN 'opened' ELSE status END,
         viewed_at = COALESCE(viewed_at, NOW())
     WHERE id = ?`,
    [id]
  );
};

const markInvitationTermsAccepted = async (id) => {
  await db.execute(
    `UPDATE invitation_signers
     SET legal_accepted_at = COALESCE(legal_accepted_at, NOW())
     WHERE id = ?`,
    [id]
  );
};

const markInvitationSigned = async ({
  id,
  signedFilename,
  signedPath,
  certificateSubjectCn,
  certificateIssuerCn,
  verificationCode,
  verificationUrl,
}) => {
  await db.execute(
    `UPDATE invitation_signers
     SET status = 'signed',
         signed_at = NOW(),
         signed_filename = ?,
         signed_path = ?,
         certificate_subject_cn = ?,
         certificate_issuer_cn = ?,
         verification_code = ?,
         verification_url = ?
     WHERE id = ?`,
    [signedFilename, signedPath, certificateSubjectCn || null, certificateIssuerCn || null, verificationCode || null, verificationUrl || null, id]
  );
};

const invalidateInvitationToken = async (id, replacementToken) => {
  await db.execute(
    `UPDATE invitation_signers
     SET token = ?, token_expires = NOW()
     WHERE id = ?`,
    [replacementToken, id]
  );
};

const activateInvitation = async (id) => {
  await db.execute(
    `UPDATE invitation_signers
     SET status = 'sent',
         sent_at = COALESCE(sent_at, NOW())
     WHERE id = ?`,
    [id]
  );
};

const updateFlowProgress = async ({ flowId, currentSignedFilename, currentSignedPath, completedInvites, status }) => {
  await db.execute(
    `UPDATE invitation_flows
     SET current_signed_filename = ?,
         current_signed_path = ?,
         completed_invites = ?,
         status = ?
     WHERE id = ?`,
    [currentSignedFilename, currentSignedPath, completedInvites, status, flowId]
  );
};

const findNextInvitation = async (flowId) => {
  const [rows] = await db.execute(
    `SELECT * FROM invitation_signers
     WHERE flow_id = ? AND status = 'queued'
     ORDER BY order_index ASC
     LIMIT 1`,
    [flowId]
  );
  return rows[0] || null;
};

const countSignedInvitations = async (flowId) => {
  const [rows] = await db.execute(
    `SELECT COUNT(*) AS total
     FROM invitation_signers
     WHERE flow_id = ? AND status = 'signed'`,
    [flowId]
  );
  return Number(rows[0]?.total || 0);
};

const countInvitations = async (flowId) => {
  const [rows] = await db.execute(
    `SELECT COUNT(*) AS total
     FROM invitation_signers
     WHERE flow_id = ?`,
    [flowId]
  );
  return Number(rows[0]?.total || 0);
};

const updateFlowCounts = async ({ flowId, totalInvites, completedInvites, status }) => {
  await db.execute(
    `UPDATE invitation_flows
     SET total_invites = ?,
         completed_invites = ?,
         status = ?
     WHERE id = ?`,
    [totalInvites, completedInvites, status, flowId]
  );
};

const removeInvitation = async (id) => {
  await db.execute('DELETE FROM invitation_signers WHERE id = ?', [id]);
};

module.exports = {
  ensureSchema,
  createFlow,
  createInvitation,
  findFlowByDocumentOwner,
  findFlowById,
  listInvitationsByFlow,
  getMaxOrderIndex,
  findInvitationByIdForOwner,
  findInvitationByToken,
  markInvitationSent,
  markInvitationViewed,
  markInvitationTermsAccepted,
  markInvitationSigned,
  invalidateInvitationToken,
  activateInvitation,
  updateFlowProgress,
  findNextInvitation,
  countSignedInvitations,
  countInvitations,
  updateFlowCounts,
  removeInvitation,
};