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

const router = express.Router({ mergeParams: true });

const ALIVE_STATUSES = ['alive', 'dead', 'unknown', 'missing'];

const OPTIONAL_TEXT_FIELDS = [
  'description',
  'notes',
  'motivations',
  'appearance',
  'age',
  'gender',
  'pronouns',
  'voice',
  'distinguishing_features',
  'faction',
  'occupation',
  'social_status',
  'relationship_to_pc',
  'loyalty',
  'personality_traits',
  'fears',
  'desires',
  'secrets',
  'first_encountered',
  'last_seen',
  'current_location',
  'current_goal',
  'role_in_threads',
  'disposition',
];

const getCampaignByIdStmt = db.prepare('SELECT id FROM campaigns WHERE id = ?');
const listNpcsStmt = db.prepare('SELECT * FROM npcs WHERE campaign_id = ? ORDER BY created_at DESC');
const getNpcStmt = db.prepare('SELECT * FROM npcs WHERE id = ? AND campaign_id = ?');

const insertNpcStmt = db.prepare(`
  INSERT INTO npcs (
    campaign_id, name, description, notes, motivations, appearance, age,
    gender, pronouns, voice, distinguishing_features, faction, occupation,
    social_status, relationship_to_pc, loyalty, personality_traits, fears,
    desires, secrets, first_encountered, last_seen, current_location,
    current_goal, role_in_threads, alive_status, disposition
  ) VALUES (
    @campaign_id, @name, @description, @notes, @motivations, @appearance, @age,
    @gender, @pronouns, @voice, @distinguishing_features, @faction, @occupation,
    @social_status, @relationship_to_pc, @loyalty, @personality_traits, @fears,
    @desires, @secrets, @first_encountered, @last_seen, @current_location,
    @current_goal, @role_in_threads, @alive_status, @disposition
  )
`);

const updateNpcStmt = db.prepare(`
  UPDATE npcs SET
    name = @name,
    description = @description,
    notes = @notes,
    motivations = @motivations,
    appearance = @appearance,
    age = @age,
    gender = @gender,
    pronouns = @pronouns,
    voice = @voice,
    distinguishing_features = @distinguishing_features,
    faction = @faction,
    occupation = @occupation,
    social_status = @social_status,
    relationship_to_pc = @relationship_to_pc,
    loyalty = @loyalty,
    personality_traits = @personality_traits,
    fears = @fears,
    desires = @desires,
    secrets = @secrets,
    first_encountered = @first_encountered,
    last_seen = @last_seen,
    current_location = @current_location,
    current_goal = @current_goal,
    role_in_threads = @role_in_threads,
    alive_status = @alive_status,
    disposition = @disposition
  WHERE id = @id AND campaign_id = @campaign_id
`);

const deleteNpcStmt = db.prepare('DELETE FROM npcs WHERE id = ? AND campaign_id = ?');

function parsePositiveInt(raw, res, label) {
  const value = Number(raw);
  if (!Number.isInteger(value) || value <= 0) {
    res.status(400).json({ error: `${label} must be a positive integer` });
    return null;
  }
  return value;
}

function loadCampaignId(req, res) {
  const campaignId = parsePositiveInt(req.params.campaignId, res, 'campaign_id');
  if (campaignId === null) return null;

  if (!getCampaignByIdStmt.get(campaignId)) {
    res.status(404).json({ error: 'campaign not found' });
    return null;
  }
  return campaignId;
}

// Shared by create and update — PUT sends the full form, so both treat
// name/alive_status the same way rather than supporting partial patches.
function parseNpcPayload(body, res) {
  const name = typeof body.name === 'string' ? body.name.trim() : '';
  if (!name) {
    res.status(400).json({ error: 'name is required' });
    return null;
  }

  const aliveStatus = body.alive_status === undefined ? 'alive' : body.alive_status;
  if (!ALIVE_STATUSES.includes(aliveStatus)) {
    res.status(400).json({ error: `alive_status must be one of: ${ALIVE_STATUSES.join(', ')}` });
    return null;
  }

  const payload = { name, alive_status: aliveStatus };

  for (const field of OPTIONAL_TEXT_FIELDS) {
    if (field === 'disposition') continue;
    const value = body[field];
    if (value === undefined || value === null) {
      payload[field] = null;
    } else if (typeof value === 'string') {
      payload[field] = value;
    } else {
      res.status(400).json({ error: `${field} must be a string or null` });
      return null;
    }
  }

  const disposition = body.disposition;
  if (disposition === undefined) {
    payload.disposition = 'unknown';
  } else if (disposition === null || typeof disposition === 'string') {
    payload.disposition = disposition;
  } else {
    res.status(400).json({ error: 'disposition must be a string or null' });
    return null;
  }

  return payload;
}

function withErrorHandling(handler) {
  return (req, res) => {
    try {
      handler(req, res);
    } catch (err) {
      console.error(err);
      res.status(500).json({ error: 'unexpected server error' });
    }
  };
}

router.get('/', withErrorHandling((req, res) => {
  const campaignId = loadCampaignId(req, res);
  if (campaignId === null) return;

  res.json({ data: listNpcsStmt.all(campaignId) });
}));

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

  const id = parsePositiveInt(req.params.id, res, 'id');
  if (id === null) return;

  const npc = getNpcStmt.get(id, campaignId);
  if (!npc) {
    return res.status(404).json({ error: 'npc not found' });
  }
  res.json({ data: npc });
}));

router.post('/', withErrorHandling((req, res) => {
  const campaignId = loadCampaignId(req, res);
  if (campaignId === null) return;

  const payload = parseNpcPayload(req.body, res);
  if (payload === null) return;

  const result = insertNpcStmt.run({ ...payload, campaign_id: campaignId });
  res.status(201).json({ data: getNpcStmt.get(result.lastInsertRowid, campaignId) });
}));

router.put('/:id', withErrorHandling((req, res) => {
  const campaignId = loadCampaignId(req, res);
  if (campaignId === null) return;

  const id = parsePositiveInt(req.params.id, res, 'id');
  if (id === null) return;

  if (!getNpcStmt.get(id, campaignId)) {
    return res.status(404).json({ error: 'npc not found' });
  }

  const payload = parseNpcPayload(req.body, res);
  if (payload === null) return;

  updateNpcStmt.run({ ...payload, id, campaign_id: campaignId });
  res.json({ data: getNpcStmt.get(id, campaignId) });
}));

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

  const id = parsePositiveInt(req.params.id, res, 'id');
  if (id === null) return;

  if (!getNpcStmt.get(id, campaignId)) {
    return res.status(404).json({ error: 'npc not found' });
  }

  deleteNpcStmt.run(id, campaignId);
  res.json({ data: { id } });
}));

module.exports = router;