#!/usr/bin/env node
'use strict';

const fs = require('fs');
const path = require('path');

const REQUIRED_CHART_PROPS = [
  'chartType', 'interpolation', 'category', 'categoryType',
  'xAxisType', 'xAxisPropertyType', 'yAxisProperty', 'yAxisPropertyType',
  'action', 'width', 'height', 'colors',
];

const CHANNEL_PREFIXES = ['cmd:', 'evt:', 'setup:'];

function lintFlow(flowPath) {
  const findings = [];
  let nodes;
  try {
    const raw = fs.readFileSync(flowPath, 'utf8');
    nodes = JSON.parse(raw);
  } catch (err) {
    findings.push({ rule: 'PARSE', severity: 'error', msg: `JSON parse failed: ${err.message}` });
    return findings;
  }
  if (!Array.isArray(nodes)) {
    findings.push({ rule: 'SHAPE', severity: 'error', msg: 'Top-level must be an array of nodes.' });
    return findings;
  }
  const byId = new Map(nodes.filter((n) => n && n.id).map((n) => [n.id, n]));
  for (const n of nodes) {
    if (!n || typeof n.type !== 'string') continue;
    checkUiNodeXY(n, findings);
    checkUiChart(n, findings);
    checkInject(n, findings);
    checkLinkPair(n, byId, findings);
    checkDebugLog(n, findings);
    checkBackwardWires(n, findings);
  }
  checkGroupWidths(nodes, findings);
  return findings;
}

const UI_CONFIG_TYPES = new Set(['ui-base', 'ui-theme', 'ui-page', 'ui-group', 'ui-spacer', 'ui-control']);

function checkUiNodeXY(n, findings) {
  if (!n.type.startsWith('ui-')) return;
  if (UI_CONFIG_TYPES.has(n.type)) return;
  if ((!n.x && !n.y) || (n.x === 0 && n.y === 0)) {
    findings.push({
      rule: 'UI_XY',
      severity: 'error',
      node: n.id,
      msg: `${n.type} "${n.name || n.id}" has no editor position (x/y both 0 or missing) — will pile up at canvas origin.`,
    });
  }
}

function checkUiChart(n, findings) {
  if (n.type !== 'ui-chart') return;
  const missing = REQUIRED_CHART_PROPS.filter((p) => n[p] === undefined || n[p] === null || n[p] === '');
  for (const m of missing) {
    if (m === 'xAxisProperty' || m === 'xAxisFormat') continue;
    findings.push({
      rule: 'UI_CHART_PROP',
      severity: 'error',
      node: n.id,
      msg: `ui-chart "${n.name || n.id}" missing required property: ${m}`,
    });
  }
  if (typeof n.width === 'string') {
    findings.push({ rule: 'UI_CHART_TYPE', severity: 'warn', node: n.id, msg: `ui-chart width should be number, got string "${n.width}"` });
  }
  if (typeof n.height === 'string') {
    findings.push({ rule: 'UI_CHART_TYPE', severity: 'warn', node: n.id, msg: `ui-chart height should be number, got string "${n.height}"` });
  }
  if (Array.isArray(n.colors) && n.colors.length < 3) {
    findings.push({ rule: 'UI_CHART_PALETTE', severity: 'warn', node: n.id, msg: 'ui-chart palette has <3 colors; series may collide.' });
  }
}

function checkInject(n, findings) {
  if (n.type !== 'inject') return;
  if (n.payloadType !== 'json') return;
  if (!Array.isArray(n.props) || n.props.length === 0) {
    findings.push({
      rule: 'INJECT_JSON_PROPS',
      severity: 'error',
      node: n.id,
      msg: `inject "${n.name || n.id}" has payloadType=json but no props[] — Node-RED will silently treat payload as string.`,
    });
    return;
  }
  const payloadProp = n.props.find((p) => p && p.p === 'payload');
  if (payloadProp && payloadProp.vt && payloadProp.vt !== 'json') {
    findings.push({
      rule: 'INJECT_JSON_PROPS',
      severity: 'warn',
      node: n.id,
      msg: `inject "${n.name || n.id}" has payloadType=json but props.payload.vt=${payloadProp.vt}.`,
    });
  }
}

function checkLinkPair(n, byId, findings) {
  if (n.type !== 'link out' && n.type !== 'link in') return;
  if (n.name && !CHANNEL_PREFIXES.some((p) => n.name.startsWith(p))) {
    findings.push({
      rule: 'LINK_CHANNEL_NAME',
      severity: 'warn',
      node: n.id,
      msg: `${n.type} "${n.name}" should start with cmd: / evt: / setup: (channel naming convention).`,
    });
  }
  if (!Array.isArray(n.links)) return;
  for (const linkedId of n.links) {
    const other = byId.get(linkedId);
    if (!other) {
      findings.push({
        rule: 'LINK_BROKEN',
        severity: 'error',
        node: n.id,
        msg: `${n.type} "${n.name || n.id}" points at non-existent node id "${linkedId}".`,
      });
      continue;
    }
    const otherType = n.type === 'link out' ? 'link in' : 'link out';
    if (other.type !== otherType) {
      findings.push({
        rule: 'LINK_PAIR_TYPE',
        severity: 'error',
        node: n.id,
        msg: `${n.type} "${n.name || n.id}" pairs with non-${otherType} "${other.type}".`,
      });
      continue;
    }
    if (Array.isArray(other.links) && !other.links.includes(n.id)) {
      findings.push({
        rule: 'LINK_PAIR_ASYMMETRIC',
        severity: 'error',
        node: n.id,
        msg: `${n.type} "${n.name || n.id}" → ${otherType} "${other.name || other.id}" — partner does not link back.`,
      });
    }
  }
}

function checkDebugLog(n, findings) {
  if (n.enableLog === 'debug') {
    findings.push({
      rule: 'DEBUG_LOG_IN_FLOW',
      severity: 'warn',
      node: n.id,
      msg: `${n.type} "${n.name || n.id}" has enableLog:"debug" — fills container log in seconds; remove before commit.`,
    });
  }
}

function checkBackwardWires(n, findings) {
  if (!Array.isArray(n.wires) || typeof n.x !== 'number') return;
  for (const portWires of n.wires) {
    if (!Array.isArray(portWires)) continue;
    for (const targetId of portWires) {
      if (targetId === n.id) {
        findings.push({
          rule: 'SELF_LOOP',
          severity: 'error',
          node: n.id,
          msg: `${n.type} "${n.name || n.id}" wires to itself — will fire >250k msg/s.`,
        });
      }
    }
  }
}

function checkGroupWidths(nodes, findings) {
  const pages = new Map();
  for (const n of nodes) {
    if (!n || n.type !== 'ui-group') continue;
    if (typeof n.width !== 'number' || !n.page) continue;
    const arr = pages.get(n.page) || [];
    arr.push({ id: n.id, name: n.name, width: n.width });
    pages.set(n.page, arr);
  }
  for (const [pageId, groups] of pages) {
    const total = groups.reduce((s, g) => s + g.width, 0);
    if (total % 12 !== 0) {
      findings.push({
        rule: 'GROUP_WIDTH_SUM',
        severity: 'warn',
        msg: `ui-page "${pageId}" has groups summing to width=${total}; should be a multiple of 12 (12-column grid).`,
      });
    }
  }
}

function findFlows(repoRoot) {
  const out = [];
  function walk(dir) {
    if (!fs.existsSync(dir)) return;
    for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
      const full = path.join(dir, entry.name);
      if (entry.isDirectory()) {
        if (entry.name === 'node_modules' || entry.name.startsWith('.')) continue;
        walk(full);
      } else if (entry.isFile() && /\.flow\.json$|\d+.*\.json$/.test(entry.name) && /examples?/.test(full)) {
        out.push(full);
      }
    }
  }
  walk(path.join(repoRoot, 'nodes'));
  walk(path.join(repoRoot, 'examples'));
  return out;
}

function report(flowPath, findings, json) {
  if (json) {
    process.stdout.write(JSON.stringify({ flow: flowPath, findings }) + '\n');
    return findings.some((f) => f.severity === 'error');
  }
  if (findings.length === 0) {
    process.stdout.write(`OK  ${flowPath}\n`);
    return false;
  }
  const errs = findings.filter((f) => f.severity === 'error').length;
  const warns = findings.filter((f) => f.severity === 'warn').length;
  process.stdout.write(`\n${errs ? 'FAIL' : 'WARN'}  ${flowPath}  (${errs} err, ${warns} warn)\n`);
  for (const f of findings) {
    const tag = f.severity === 'error' ? 'ERR ' : 'WARN';
    const nodeRef = f.node ? `[${f.node}] ` : '';
    process.stdout.write(`  ${tag} ${f.rule}: ${nodeRef}${f.msg}\n`);
  }
  return errs > 0;
}

function main() {
  const args = process.argv.slice(2);
  const json = args.includes('--json');
  const positional = args.filter((a) => !a.startsWith('--'));
  const repoRoot = path.resolve(__dirname, '../../..');
  const targets = positional.length === 0
    ? findFlows(repoRoot)
    : positional.flatMap((p) => {
      const full = path.resolve(p);
      if (fs.existsSync(full) && fs.statSync(full).isDirectory()) return findFlows(full);
      return [full];
    });
  if (targets.length === 0) {
    process.stderr.write('No flow files found.\n');
    process.exit(2);
  }
  let fail = false;
  for (const flowPath of targets) {
    const findings = lintFlow(flowPath);
    const flowFail = report(flowPath, findings, json);
    if (flowFail) fail = true;
  }
  process.exit(fail ? 1 : 0);
}

if (require.main === module) main();

module.exports = { lintFlow };