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

const router = express.Router();

const CHAOS_MIN = 1;
const CHAOS_MAX = 9;

const listCampaigns = db.prepare(`
  SELECT campaigns.*, systems.name AS system_name, systems.slug AS system_slug
  FROM campaigns
  JOIN systems ON systems.id = campaigns.system_id
  ORDER BY campaigns.created_at DESC
`);

const getCampaignById = db.prepare(`
  SELECT campaigns.*, systems.name AS system_name, systems.slug AS system_slug
  FROM campaigns
  JOIN systems ON systems.id = campaigns.system_id
  WHERE campaigns.id = ?
`);

const getSystemById = db.prepare('SELECT id FROM systems WHERE id = ?');

const insertCampaign = db.prepare(`
  INSERT INTO campaigns (name, system_id)
  VALUES (@name, @system_id)
`);

const updateCampaignStmt = db.prepare(`
  UPDATE campaigns
  SET name = @name, chaos_factor = @chaos_factor, updated_at = datetime('now')
  WHERE id = @id
`);

const deleteCampaignCascade = db.transaction((id) => {
  const cairnCharacterIds = db
    .prepare('SELECT id FROM characters_cairn WHERE campaign_id = ?')
    .all(id)
    .map((row) => row.id);
  for (const characterId of cairnCharacterIds) {
    db.prepare('DELETE FROM cairn_inventory WHERE character_id = ?').run(characterId);
  }

  const ironswornCharacterIds = db
    .prepare('SELECT id FROM characters_ironsworn WHERE campaign_id = ?')
    .all(id)
    .map((row) => row.id);
  for (const characterId of ironswornCharacterIds) {
    db.prepare('DELETE FROM ironsworn_assets WHERE character_id = ?').run(characterId);
  }

  const shadowrunCharacterIds = db
    .prepare('SELECT id FROM characters_shadowrun WHERE campaign_id = ?')
    .all(id)
    .map((row) => row.id);
  for (const characterId of shadowrunCharacterIds) {
    db.prepare('DELETE FROM shadowrun_skills WHERE character_id = ?').run(characterId);
    db.prepare('DELETE FROM shadowrun_contacts WHERE character_id = ?').run(characterId);
    db.prepare('DELETE FROM shadowrun_qualities WHERE character_id = ?').run(characterId);
  }

  db.prepare('DELETE FROM characters_dnd5e WHERE campaign_id = ?').run(id);
  db.prepare('DELETE FROM characters_morkborg WHERE campaign_id = ?').run(id);
  db.prepare('DELETE FROM characters_cairn WHERE campaign_id = ?').run(id);
  db.prepare('DELETE FROM characters_chaalt WHERE campaign_id = ?').run(id);
  db.prepare('DELETE FROM characters_ironsworn WHERE campaign_id = ?').run(id);
  db.prepare('DELETE FROM characters_shadowrun WHERE campaign_id = ?').run(id);

  db.prepare('DELETE FROM ironsworn_vows WHERE campaign_id = ?').run(id);
  db.prepare('DELETE FROM threads WHERE campaign_id = ?').run(id);
  db.prepare('DELETE FROM npcs WHERE campaign_id = ?').run(id);
  db.prepare('DELETE FROM session_logs WHERE campaign_id = ?').run(id);
  db.prepare('DELETE FROM campaign_docs WHERE campaign_id = ?').run(id);
  db.prepare('DELETE FROM custom_tables WHERE campaign_id = ?').run(id);

  db.prepare('DELETE FROM campaigns WHERE id = ?').run(id);
});

function parseId(rawId, res) {
  const id = Number(rawId);
  if (!Number.isInteger(id)) {
    res.status(400).json({ error: 'id must be an integer' });
    return null;
  }
  return id;
}

router.get('/', (req, res) => {
  res.json(listCampaigns.all());
});

router.post('/', (req, res) => {
  const { name, system_id: systemId } = req.body;

  if (typeof name !== 'string' || !name.trim()) {
    return res.status(400).json({ error: 'name is required' });
  }
  if (!Number.isInteger(systemId)) {
    return res.status(400).json({ error: 'system_id is required' });
  }
  if (!getSystemById.get(systemId)) {
    return res.status(400).json({ error: 'system_id does not exist' });
  }

  const result = insertCampaign.run({ name: name.trim(), system_id: systemId });
  res.status(201).json(getCampaignById.get(result.lastInsertRowid));
});

router.get('/:id', (req, res) => {
  const id = parseId(req.params.id, res);
  if (id === null) return;

  const campaign = getCampaignById.get(id);
  if (!campaign) {
    return res.status(404).json({ error: 'campaign not found' });
  }
  res.json(campaign);
});

router.patch('/:id', (req, res) => {
  const id = parseId(req.params.id, res);
  if (id === null) return;

  const existing = getCampaignById.get(id);
  if (!existing) {
    return res.status(404).json({ error: 'campaign not found' });
  }

  let name = existing.name;
  if (req.body.name !== undefined) {
    name = String(req.body.name).trim();
    if (!name) {
      return res.status(400).json({ error: 'name cannot be empty' });
    }
  }

  let chaosFactor = existing.chaos_factor;
  if (req.body.chaos_factor !== undefined) {
    const parsed = Number(req.body.chaos_factor);
    if (!Number.isInteger(parsed)) {
      return res.status(400).json({ error: 'chaos_factor must be an integer' });
    }
    chaosFactor = Math.min(CHAOS_MAX, Math.max(CHAOS_MIN, parsed));
  }

  updateCampaignStmt.run({ id, name, chaos_factor: chaosFactor });
  res.json(getCampaignById.get(id));
});

router.delete('/:id', (req, res) => {
  const id = parseId(req.params.id, res);
  if (id === null) return;

  const existing = getCampaignById.get(id);
  if (!existing) {
    return res.status(404).json({ error: 'campaign not found' });
  }

  deleteCampaignCascade(id);
  res.status(204).end();
});

module.exports = router;