'use strict';
const path = require('path');
const Database = require('better-sqlite3');

const DB_PATH = process.env.DB_PATH || path.join(__dirname, 'data', 'datahub.db');
const db = new Database(DB_PATH);
db.pragma('journal_mode = WAL');
db.pragma('foreign_keys = ON');

function init() {
  db.exec(`
    CREATE TABLE IF NOT EXISTS users (
      id            INTEGER PRIMARY KEY AUTOINCREMENT,
      username      TEXT UNIQUE NOT NULL,
      email         TEXT UNIQUE NOT NULL CHECK (length(trim(email)) > 0),
      password_hash TEXT NOT NULL,
      role          TEXT NOT NULL DEFAULT 'user',      -- 'admin' | 'user'
      mfa_enabled   INTEGER NOT NULL DEFAULT 0,
      mfa_secret    TEXT,
      avatar        TEXT,               -- stored filename of the user's picture
      avatar_mime   TEXT,
      created_at    TEXT NOT NULL DEFAULT (datetime('now'))
    );

    CREATE TABLE IF NOT EXISTS folders (
      id            INTEGER PRIMARY KEY AUTOINCREMENT,
      name          TEXT NOT NULL,
      parent_id     INTEGER REFERENCES folders(id) ON DELETE CASCADE,
      -- Date the material in this folder was recorded (YYYY-MM-DD).
      -- "Legal Validity" is derived from it: recorded date + 30 days.
      recorded_date TEXT,
      created_by    INTEGER REFERENCES users(id),
      created_at    TEXT NOT NULL DEFAULT (datetime('now'))
    );

    CREATE TABLE IF NOT EXISTS files (
      id            INTEGER PRIMARY KEY AUTOINCREMENT,
      name          TEXT NOT NULL,             -- display name
      stored_name   TEXT NOT NULL,             -- name on disk
      size          INTEGER NOT NULL DEFAULT 0,
      mime          TEXT,
      folder_id     INTEGER REFERENCES folders(id) ON DELETE CASCADE,
      uploaded_by   INTEGER REFERENCES users(id),
      created_at    TEXT NOT NULL DEFAULT (datetime('now'))
    );

    CREATE TABLE IF NOT EXISTS access_requests (
      id            INTEGER PRIMARY KEY AUTOINCREMENT,
      user_id       INTEGER NOT NULL REFERENCES users(id),
      target_type   TEXT NOT NULL,             -- 'file' | 'folder'
      target_id     INTEGER NOT NULL,
      target_name   TEXT NOT NULL,
      status        TEXT NOT NULL DEFAULT 'pending', -- pending | approved | denied
      decided_by    INTEGER REFERENCES users(id),
      -- How long the approval lasts ('24h' | '15d' | '30d' | 'forever')
      -- and when it runs out. NULL expiry means it never expires.
      access_duration   TEXT,
      access_expires_at TEXT,
      created_at    TEXT NOT NULL DEFAULT (datetime('now')),
      decided_at    TEXT
    );

    CREATE TABLE IF NOT EXISTS email_templates (
      key          TEXT PRIMARY KEY,           -- 'request_to_admin' | 'approval_to_user' | 'denial_to_user'
      subject      TEXT NOT NULL,
      body_html    TEXT NOT NULL,
      updated_at   TEXT NOT NULL DEFAULT (datetime('now'))
    );

    CREATE TABLE IF NOT EXISTS brand_images (
      id           INTEGER PRIMARY KEY AUTOINCREMENT,
      label        TEXT NOT NULL,
      stored_name  TEXT NOT NULL,
      mime         TEXT,
      created_at   TEXT NOT NULL DEFAULT (datetime('now'))
    );

    CREATE TABLE IF NOT EXISTS logs (
      id          INTEGER PRIMARY KEY AUTOINCREMENT,
      ts          TEXT NOT NULL DEFAULT (datetime('now')),
      actor       TEXT,                         -- username or 'system'
      actor_id    INTEGER,
      action      TEXT NOT NULL,                -- e.g. FILE_UPLOAD
      page        TEXT,                         -- 'Data Management' | 'View Data' | ...
      detail      TEXT,
      ip          TEXT
    );

    CREATE TABLE IF NOT EXISTS settings (
      key   TEXT PRIMARY KEY,
      value TEXT
    );

    -- Entries shown on the "Version Control" page (managed from Data Management)
    CREATE TABLE IF NOT EXISTS version_entries (
      id           INTEGER PRIMARY KEY AUTOINCREMENT,
      version      TEXT NOT NULL,
      title        TEXT,
      released_on  TEXT,
      notes        TEXT,
      sort_order   INTEGER NOT NULL DEFAULT 0,
      created_by   INTEGER REFERENCES users(id),
      created_at   TEXT NOT NULL DEFAULT (datetime('now')),
      updated_at   TEXT
    );
    -- Entries shown on the "Legislation" page (managed from Data Management)
    CREATE TABLE IF NOT EXISTS legislation_entries (
      id           INTEGER PRIMARY KEY AUTOINCREMENT,
      reference    TEXT,
      title        TEXT NOT NULL,
      effective_date TEXT,
      summary      TEXT,
      link_url     TEXT,
      sort_order   INTEGER NOT NULL DEFAULT 0,
      created_by   INTEGER REFERENCES users(id),
      created_at   TEXT NOT NULL DEFAULT (datetime('now')),
      updated_at   TEXT
    );

    -- Every message the system sends (and any inbound message that is
    -- recorded), independent of the general audit log.
    CREATE TABLE IF NOT EXISTS mail_log (
      id           INTEGER PRIMARY KEY AUTOINCREMENT,
      ts           TEXT NOT NULL DEFAULT (datetime('now')),
      direction    TEXT NOT NULL DEFAULT 'sent',   -- 'sent' | 'received'
      status       TEXT NOT NULL,                  -- 'delivered' | 'queued' | 'failed'
      from_addr    TEXT,
      to_addr      TEXT,
      subject      TEXT,
      body_preview TEXT,
      attachments  TEXT,
      error        TEXT,
      context      TEXT,
      actor        TEXT
    );
  `);
}

/**
 * Add columns introduced after a database was first created.
 * SQLite's ALTER TABLE ADD COLUMN is safe and non-destructive: existing rows
 * simply get NULL for the new column.
 */
function migrate() {
  const folderCols = db.prepare('PRAGMA table_info(folders)').all().map((c) => c.name);
  if (!folderCols.includes('recorded_date')) {
    db.exec('ALTER TABLE folders ADD COLUMN recorded_date TEXT');
    console.log('[ISDSS] Added folders.recorded_date (existing folders have no date yet).');
  }

  const userCols = db.prepare('PRAGMA table_info(users)').all().map((c) => c.name);
  if (!userCols.includes('avatar')) {
    db.exec('ALTER TABLE users ADD COLUMN avatar TEXT');
    db.exec('ALTER TABLE users ADD COLUMN avatar_mime TEXT');
    console.log('[ISDSS] Added users.avatar (existing users have no picture yet).');
  }

  const reqCols = db.prepare('PRAGMA table_info(access_requests)').all().map((c) => c.name);
  if (!reqCols.includes('access_duration')) {
    db.exec("ALTER TABLE access_requests ADD COLUMN access_duration TEXT");
    // Approvals granted before this release had no expiry, so they are
    // permanent. Marking them explicitly keeps existing access working.
    db.exec("UPDATE access_requests SET access_duration = 'forever' WHERE status = 'approved'");
    console.log('[ISDSS] Added access_requests.access_duration (existing approvals kept as permanent).');
  }
  if (!reqCols.includes('access_expires_at')) {
    db.exec('ALTER TABLE access_requests ADD COLUMN access_expires_at TEXT');
    console.log('[ISDSS] Added access_requests.access_expires_at.');
  }
}

/**
 * Accounts with no email address cannot receive approval notifications.
 * New databases block this outright (CHECK constraint above); databases created
 * by earlier releases keep their original schema, so report any offenders at
 * startup instead of failing silently.
 */
function reportMissingEmails() {
  try {
    const rows = db.prepare(
      "SELECT username FROM users WHERE email IS NULL OR length(trim(email)) = 0"
    ).all();
    if (rows.length) {
      console.warn(
        `[ISDSS] ${rows.length} account(s) have no email address: ` +
        `${rows.map((r) => r.username).join(', ')}. ` +
        'Email is now mandatory — set one in Data Management → Users.'
      );
    }
    return rows.length;
  } catch (_) { return 0; }
}

module.exports = { db, init, migrate, DB_PATH, reportMissingEmails };