const { getDatabase, runInTransaction } = require('../models/database');
const {
  listIncidentsOrdered,
  getIncidentById: getIncidentRecordById,
  listIncidentEndpoints,
  getLatestIncidentUpdate,
  listIncidentUpdates,
  createIncidentRecord,
  linkIncidentEndpoint,
  createIncidentUpdate,
  updateIncidentCore,
  deleteIncidentLinksExceptSource,
  deleteAllIncidentLinks,
  markIncidentResolved,
  setIncidentAdminManaged,
  setIncidentStatus,
  getIncidentUpdateById,
  reopenIncidentRecord,
  setIncidentPostMortem,
  deleteIncidentRecord,
} = require('../data/incidentData');
const { queueIncidentNotification } = require('../services/notificationService');

// Helpers

async function enrichIncident(incident, { includeUpdates = false } = {}) {
  incident.endpoints = await listIncidentEndpoints(incident.id);

  // Always include the latest update for preview
  incident.latest_update = await getLatestIncidentUpdate(incident.id);

  if (includeUpdates) {
    incident.updates = await listIncidentUpdates(incident.id);
  }

  return incident;
}

// Public

async function getAllIncidents(req, res) {
  try {
    const incidents = await listIncidentsOrdered();

    for (const incident of incidents) {
      await enrichIncident(incident);
    }

    res.json(incidents);
  } catch (error) {
    console.error('Get incidents error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

async function getIncidentById(req, res) {
  try {
    const incident = await getIncidentRecordById(req.params.id);
    if (!incident) return res.status(404).json({ error: 'Incident not found' });

    await enrichIncident(incident, { includeUpdates: true });
    res.json(incident);
  } catch (error) {
    console.error('Get incident error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

// Admin CRUD

async function createIncident(req, res) {
  try {
    const {
      title,
      description,
      severity = 'degraded',
      status = 'investigating',
      source = 'manual',
      endpoint_ids = [],
      initial_message,
      created_by = 'admin'
    } = req.body;

    if (!title || !severity) {
      return res.status(400).json({ error: 'Title and severity are required' });
    }

    const incidentId = await runInTransaction(async () => {
      const result = await createIncidentRecord({
        title,
        description: description || '',
        severity,
        status,
        source,
      });

      for (const endpointId of endpoint_ids) {
        await linkIncidentEndpoint(result.lastID, endpointId);
      }

      if (initial_message) {
        await createIncidentUpdate(result.lastID, initial_message, status, created_by);
      }

      return result.lastID;
    });

    const incident = await getIncidentRecordById(incidentId);
    await enrichIncident(incident, { includeUpdates: true });
    await queueIncidentNotification('incident_created', incident.id, initial_message || incident.description || 'New incident created.');
    res.status(201).json(incident);
  } catch (error) {
    console.error('Create incident error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

async function updateIncident(req, res) {
  try {
    const { title, description, severity, status, endpoint_ids = [] } = req.body;
    const existing = await getIncidentRecordById(req.params.id);
    if (!existing) return res.status(404).json({ error: 'Incident not found' });

    // Mark as admin-managed if a human is editing an auto-created incident
    const adminManaged = existing.auto_created ? 1 : (existing.admin_managed || 0);

    await runInTransaction(async () => {
      await updateIncidentCore(req.params.id, {
        title,
        description: description || '',
        severity,
        status,
        admin_managed: adminManaged,
      });

      if (existing.auto_created && existing.source_endpoint_id) {
        await deleteIncidentLinksExceptSource(req.params.id, existing.source_endpoint_id);
        for (const endpointId of endpoint_ids) {
          await linkIncidentEndpoint(req.params.id, endpointId, true);
        }
        await linkIncidentEndpoint(req.params.id, existing.source_endpoint_id, true);
      } else {
        await deleteAllIncidentLinks(req.params.id);
        for (const endpointId of endpoint_ids) {
          await linkIncidentEndpoint(req.params.id, endpointId);
        }
      }
    });

    const incident = await getIncidentRecordById(req.params.id);
    await enrichIncident(incident, { includeUpdates: true });
    await queueIncidentNotification('incident_updated', incident.id, 'Incident details were updated.');
    res.json(incident);
  } catch (error) {
    console.error('Update incident error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

async function resolveIncident(req, res) {
  try {
    const { message, created_by = 'admin' } = req.body;
    const existing = await getIncidentRecordById(req.params.id);
    if (!existing) return res.status(404).json({ error: 'Incident not found' });

    // Resolving an auto-incident manually marks it as admin-managed
    const adminManaged = existing.auto_created ? 1 : (existing.admin_managed || 0);

    const closingMessage = message || 'This incident has been resolved.';
    await runInTransaction(async () => {
      await markIncidentResolved(req.params.id, adminManaged);
      await createIncidentUpdate(req.params.id, closingMessage, 'resolved', created_by);
    });

    const incident = await getIncidentRecordById(req.params.id);
    await enrichIncident(incident, { includeUpdates: true });
    await queueIncidentNotification('incident_resolved', incident.id, closingMessage);
    res.json(incident);
  } catch (error) {
    console.error('Resolve incident error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

async function deleteIncident(req, res) {
  try {
    await deleteIncidentRecord(req.params.id);
    res.json({ success: true });
  } catch (error) {
    console.error('Delete incident error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

// Incident Updates (timeline)

async function addIncidentUpdate(req, res) {
  try {
    const { message, status_label, created_by = 'admin' } = req.body;

    if (!message) {
      return res.status(400).json({ error: 'Message is required' });
    }

    const incident = await getIncidentRecordById(req.params.id);
    if (!incident) return res.status(404).json({ error: 'Incident not found' });

    const updateId = await runInTransaction(async () => {
      if (incident.auto_created && !incident.admin_managed) {
        await setIncidentAdminManaged(req.params.id, 1);
      }

      const result = await createIncidentUpdate(req.params.id, message, status_label || null, created_by);
      if (status_label) {
        await setIncidentStatus(req.params.id, status_label);
      }
      return result.lastID;
    });

    const update = await getIncidentUpdateById(updateId);
    await queueIncidentNotification('incident_updated', req.params.id, message);
    res.status(201).json(update);
  } catch (error) {
    console.error('Add incident update error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

// Maintenance Windows

async function getAllMaintenance(req, res) {
  try {
    const db = getDatabase();
    const windows = await db.all(`
      SELECT mw.*, e.name AS endpoint_name
      FROM maintenance_windows mw
      LEFT JOIN endpoints e ON e.id = mw.endpoint_id
      ORDER BY mw.start_time DESC
    `);
    res.json(windows);
  } catch (error) {
    console.error('Get maintenance error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

async function createMaintenance(req, res) {
  try {
    const { title, description, endpoint_id, start_time, end_time } = req.body;

    if (!title || !start_time || !end_time) {
      return res.status(400).json({ error: 'Title, start_time, and end_time are required' });
    }

    const db = getDatabase();
    const result = await db.run(
      `INSERT INTO maintenance_windows (title, description, endpoint_id, start_time, end_time)
       VALUES (?, ?, ?, ?, ?)`,
      [title, description || '', endpoint_id || null, start_time, end_time]
    );

    const window = await db.get('SELECT * FROM maintenance_windows WHERE id = ?', [result.lastID]);
    res.status(201).json(window);
  } catch (error) {
    console.error('Create maintenance error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

async function updateMaintenance(req, res) {
  try {
    const { title, description, endpoint_id, start_time, end_time } = req.body;
    const db = getDatabase();

    await db.run(
      `UPDATE maintenance_windows
       SET title = ?, description = ?, endpoint_id = ?, start_time = ?, end_time = ?,
           updated_at = CURRENT_TIMESTAMP
       WHERE id = ?`,
      [title, description || '', endpoint_id || null, start_time, end_time, req.params.id]
    );

    const window = await db.get('SELECT * FROM maintenance_windows WHERE id = ?', [req.params.id]);
    res.json(window);
  } catch (error) {
    console.error('Update maintenance error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

async function deleteMaintenance(req, res) {
  try {
    const db = getDatabase();
    await db.run('DELETE FROM maintenance_windows WHERE id = ?', [req.params.id]);
    res.json({ success: true });
  } catch (error) {
    console.error('Delete maintenance error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

// Reopen

async function reopenIncident(req, res) {
  try {
    const incident = await getIncidentRecordById(req.params.id);
    if (!incident) return res.status(404).json({ error: 'Incident not found' });

    if (!incident.resolved_at) {
      return res.status(400).json({ error: 'Incident is not resolved' });
    }

    // Admins may re-open within 7 days of resolution
    const REOPEN_WINDOW_DAYS = 7;
    const resolvedAt = new Date(incident.resolved_at.replace(' ', 'T') + 'Z');
    const ageMs = Date.now() - resolvedAt.getTime();
    const ageDays = ageMs / (1000 * 60 * 60 * 24);

    if (ageDays > REOPEN_WINDOW_DAYS) {
      return res.status(403).json({
        error: `This incident can no longer be re-opened. The ${REOPEN_WINDOW_DAYS}-day re-open window has expired.`,
        expired: true,
      });
    }

    const { message = '', created_by = 'admin' } = req.body;
    await runInTransaction(async () => {
      await reopenIncidentRecord(req.params.id);
      await createIncidentUpdate(
        req.params.id,
        message || 'This incident has been re-opened by an administrator.',
        'investigating',
        created_by
      );
    });

    const updated = await getIncidentRecordById(req.params.id);
    await enrichIncident(updated, { includeUpdates: true });
    await queueIncidentNotification('incident_updated', updated.id, message || 'Incident re-opened by administrator.');
    res.json(updated);
  } catch (error) {
    console.error('Reopen incident error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

// Post-mortem

async function setPostMortem(req, res) {
  try {
    const { post_mortem } = req.body;
    const incident = await getIncidentRecordById(req.params.id);
    if (!incident) return res.status(404).json({ error: 'Incident not found' });

    await setIncidentPostMortem(req.params.id, post_mortem || null);

    const updated = await getIncidentRecordById(req.params.id);
    await enrichIncident(updated, { includeUpdates: true });
    res.json(updated);
  } catch (error) {
    console.error('Set post-mortem error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
}

module.exports = {
  getAllIncidents,
  getIncidentById,
  createIncident,
  updateIncident,
  resolveIncident,
  deleteIncident,
  addIncidentUpdate,
  reopenIncident,
  setPostMortem,
  getAllMaintenance,
  createMaintenance,
  updateMaintenance,
  deleteMaintenance,
};