// Root-cause + scope of the 608 missing staged units (READ-ONLY) for the report to John.
// Hypothesis: importer serial/date regex requires a leading digit, so hex-encoded
// (leading-letter) serials in the .DAT are never matched -> records dropped.
const fs = require('fs');
const path = require('path');
const db = require('./database/db');

const STAGE = 'C:/Shares/test/STAGE';
const STRICT = /^"(\d+-\d+[A-Za-z]?)","(\d{2}-\d{2}-\d{4})"$/;   // current importer regex
const LOOSE  = /^"([^"]+)","(\d{2}-\d{2}-\d{4})"$/;              // any serial before a date
const decode = sn => /^[A-Za-z]\d/.test(sn) ? String(sn.toUpperCase().charCodeAt(0) - 55) + sn.slice(1) : sn;

function walk(dir, re, out) { let it=[]; try{it=fs.readdirSync(dir,{withFileTypes:true})}catch{return out;}
  for(const e of it){const p=path.join(dir,e.name); if(e.isDirectory()) walk(p,re,out); else if(re.test(e.name)) out.push(p);} return out; }

(async () => {
  // ---- staged .TXT inventory ----
  const txts = walk(STAGE, /\.txt$/i, []);
  const staged = [];
  for (const f of txts) { let t; try{t=fs.readFileSync(f,'utf8')}catch{continue;}
    const sn=(t.match(/^\s*SN:\s*(\S+)/m)||[])[1]; if(!sn) continue;
    const model=(t.match(/^\s*Model:\s*(\S+)/m)||[])[1]||'';
    const date=(t.match(/^\s*Date:\s*(\d{2}-\d{2}-\d{4})/m)||[])[1]||'';
    const station=(f.match(/STAGE[\\\/]([^\\\/]+)/)||[])[1]||'';
    staged.push({ sn, dec: decode(sn), model, date, station, file: f });
  }

  // ---- which staged decoded serials are in DB ----
  const decs=[...new Set(staged.map(s=>s.dec))]; const inDb=new Set();
  for(let i=0;i<decs.length;i+=1000){ const rows=await db.query('SELECT serial_number FROM test_records WHERE serial_number = ANY($1)',[decs.slice(i,i+1000)]); for(const r of rows) inDb.add(r.serial_number); }
  const missing = staged.filter(s=>!inDb.has(s.dec));

  // ---- scan ALL .DAT sources: which serial tokens appear, strict vs letter-prefixed ----
  let dats=[]; walk('C:/Shares/test/Ate/HISTLOGS', /\.dat$/i, dats);
  let stations=[]; try{stations=fs.readdirSync('C:/Shares/test',{withFileTypes:true}).filter(d=>d.isDirectory()&&/^TS-\d+[LR]?$/i.test(d.name)).map(d=>d.name);}catch{}
  for(const s of stations) walk(path.join('C:/Shares/test',s,'LOGS'), /\.dat$/i, dats);

  const looseSet=new Set(); const letterSet=new Set(); let letterRecs=0; const letterModels=new Set();
  let fi=0;
  for(const f of dats){ fi++; if(fi%5000===0) console.log('  scan '+fi+'/'+dats.length);
    let lines; try{lines=fs.readFileSync(f,'utf8').split('\n')}catch{continue;}
    let lastModel='';
    for(const l of lines){ const t=l.trim();
      const mm=t.match(/^"([A-Z0-9][A-Z0-9 \-]*)"$/i); if(mm && !/PASS|FAIL/.test(t) && !t.includes(',')) { lastModel=mm[1].trim(); continue; }
      const m=t.match(LOOSE); if(m){ const sn=m[1]; looseSet.add(sn);
        if(/^[A-Za-z]\d/.test(sn) && !STRICT.test(t)){ letterSet.add(sn); letterRecs++; if(lastModel) letterModels.add(lastModel); } }
    }
  }

  // ---- categorize the missing ----
  const cat = { parserDrop: [], absent: [], decInDbButMiss: [] };
  for(const s of missing){
    if(letterSet.has(s.sn) || (/^[A-Za-z]\d/.test(s.sn) && looseSet.has(s.sn))) cat.parserDrop.push(s);
    else if(!looseSet.has(s.sn) && !looseSet.has(s.dec)) cat.absent.push(s);
    else cat.decInDbButMiss.push(s);
  }
  const by=(arr,k)=>{const m={};for(const x of arr){const v=(x[k]||'?');m[v]=(m[v]||0)+1;}return Object.entries(m).sort((a,b)=>b[1]-a[1]);};

  // ---- full letter-prefixed population in .DAT and how much is absent from DB ----
  const letterDecs=[...letterSet].map(decode); const letterInDb=new Set();
  for(let i=0;i<letterDecs.length;i+=1000){ const rows=await db.query('SELECT serial_number FROM test_records WHERE serial_number = ANY($1)',[letterDecs.slice(i,i+1000)]); for(const r of rows) letterInDb.add(r.serial_number); }
  const letterMissingDistinct=letterDecs.filter(d=>!letterInDb.has(d)).length;

  const out=[]; const L=s=>{out.push(s);console.log(s);};
  L('========== MISSING-UNITS ROOT CAUSE & SCOPE ==========');
  L('Staged .TXT with SN            : '+staged.length);
  L('Staged units MISSING from DB   : '+missing.length);
  L('');
  L('ROOT-CAUSE CATEGORIES (of the missing):');
  L('  Parser-drop (encoded serial w/ leading letter present in .DAT, regex rejects): '+cat.parserDrop.length);
  L('  Source .DAT has no record for this unit (data absent)                        : '+cat.absent.length);
  L('  Other (decoded present, still missing - investigate)                         : '+cat.decInDbButMiss.length);
  L('');
  L('PARSER-DROP breakdown by leading char: '+by(cat.parserDrop, 'sn').slice(0,1).length? '' : '');
  const lead=k=>{const m={};for(const x of cat.parserDrop){const c=x.sn[0].toUpperCase();m[c]=(m[c]||0)+1;}return Object.entries(m).sort((a,b)=>b[1]-a[1]);};
  L('  by leading letter: '+lead().map(([c,n])=>c+'='+n).join(', '));
  L('  by station       : '+by(cat.parserDrop,'station').map(([c,n])=>c+'='+n).join(', '));
  L('  by model (top 12): '+by(cat.parserDrop,'model').slice(0,12).map(([c,n])=>c+'='+n).join(', '));
  L('  date range       : '+(()=>{const ds=cat.parserDrop.map(s=>s.date).filter(Boolean).sort();return ds[0]+' .. '+ds[ds.length-1];})());
  L('  samples          :'); cat.parserDrop.slice(0,12).forEach(s=>L('    '+s.sn+' -> '+s.dec+'  '+s.model+'  '+s.date+'  '+s.station));
  if(cat.absent.length){ L(''); L('DATA-ABSENT samples:'); cat.absent.slice(0,10).forEach(s=>L('    '+s.sn+' -> '+s.dec+'  '+s.model+'  '+s.date+'  '+s.station)); }
  if(cat.decInDbButMiss.length){ L(''); L('OTHER samples:'); cat.decInDbButMiss.slice(0,10).forEach(s=>L('    '+s.sn+' -> '+s.dec+'  '+s.model+'  '+s.date+'  '+s.station)); }
  L('');
  L('FULL .DAT BLIND SPOT (all letter-prefixed serials the importer skips, not just staged):');
  L('  distinct letter-prefixed serials in .DAT : '+letterSet.size);
  L('  total letter-prefixed records (dropped)  : '+letterRecs);
  L('  distinct models affected                 : '+letterModels.size);
  L('  of those serials, DECODED form absent from DB: '+letterMissingDistinct+' / '+letterSet.size);

  if(process.argv[2]) fs.writeFileSync(process.argv[2], out.join('\n')+'\n');
  await db.close();
})().catch(e=>{console.error(e);process.exit(1);});