import { DatabaseSync } from 'node:sqlite';
import { mkdirSync, chmodSync } from 'node:fs';
import path from 'node:path';
import { randomUUID, createHash } from 'node:crypto';

const hash = value => createHash('sha256').update(value).digest('hex');
export function briefWeekKey(now = new Date()) {
  const date = new Date(now.getTime() + 3 * 3600000);
  date.setUTCDate(date.getUTCDate() - (date.getUTCDay()+6)%7);
  return date.toISOString().slice(0,10);
}

/** A claimed message is never blindly replayed after an interrupted provider call. */
export function createBriefOutbox(directory) {
  function transaction(work) {
    mkdirSync(directory,{recursive:true,mode:0o700});
    const file=path.join(directory,'brief.sqlite');
    const db = new DatabaseSync(file);
    try {
      chmodSync(file,0o600);
      db.exec(`PRAGMA busy_timeout=5000; PRAGMA journal_mode=WAL; PRAGMA synchronous=FULL;
        CREATE TABLE IF NOT EXISTS brief_batches(id TEXT PRIMARY KEY,week TEXT NOT NULL,email TEXT NOT NULL,manifest TEXT NOT NULL);
        CREATE TABLE IF NOT EXISTS brief_messages(batch TEXT NOT NULL,position INTEGER NOT NULL,state TEXT NOT NULL,lease TEXT,lease_until INTEGER,receipt TEXT,error TEXT,PRIMARY KEY(batch,position));
        CREATE TABLE IF NOT EXISTS brief_reviews(batch TEXT NOT NULL,position INTEGER NOT NULL,actor TEXT NOT NULL,action TEXT NOT NULL,note TEXT NOT NULL,reviewed_at TEXT NOT NULL,PRIMARY KEY(batch,position));`);
      db.exec('BEGIN IMMEDIATE');
      const result=work(db);
      db.exec('COMMIT');
      return result;
    } catch(error) { try { db.exec('ROLLBACK'); } catch {} throw error; }
    finally { db.close(); }
  }
  return {
    prepare(week,email,messages) {
      const id=hash(JSON.stringify([week,email])),manifest=JSON.stringify(messages);
      return transaction(db=>{
        const row=db.prepare('SELECT manifest FROM brief_batches WHERE id=?').get(id);
        if(row) {
          const remaining=db.prepare("SELECT COUNT(*) AS count FROM brief_messages WHERE batch=? AND state NOT IN ('accepted','skipped')").get(id).count;
          if(!remaining)return {id,closed:true,count:db.prepare('SELECT COUNT(*) AS count FROM brief_messages WHERE batch=?').get(id).count};
          const changed=row.manifest!==manifest;
          if(changed) db.prepare("UPDATE brief_messages SET state='uncertain',error=? WHERE batch=? AND state='pending'")
            .run('Haftalık özet içeriği veya alıcı kanalı değişti; yeniden gönderim öncesi inceleme gerekli.',id);
          return {id,changed};
        }
        db.prepare('INSERT INTO brief_batches VALUES (?,?,?,?)').run(id,week,email,manifest);
        const insert=db.prepare("INSERT INTO brief_messages(batch,position,state) VALUES (?,?,'pending')");
        messages.forEach((_,i)=>insert.run(id,i));
        return {id,changed:false};
      });
    },
    claim(batch,position,clock=Date.now()) {
      return transaction(db=>{
        const row=db.prepare('SELECT * FROM brief_messages WHERE batch=? AND position=?').get(batch,position);
        if(!row)throw new Error('Özet teslimat kaydı bulunamadı.');
        if(row.state==='accepted'||row.state==='skipped')return {state:row.state};
        if(row.state==='uncertain')return {state:'uncertain'};
        if(row.state==='sending') {
          if(row.lease_until>clock)return {state:'busy'};
          db.prepare("UPDATE brief_messages SET state='uncertain',error=? WHERE batch=? AND position=?").run('Kesintiye uğrayan gönderim; sağlayıcı kaydı incelenmeli.',batch,position);
          return {state:'uncertain'};
        }
        const lease=randomUUID();
        db.prepare("UPDATE brief_messages SET state='sending',lease=?,lease_until=? WHERE batch=? AND position=?").run(lease,clock+120000,batch,position);
        return {state:'sending',batch,position,lease};
      });
    },
    accept(claim,receipt) {
      if(typeof receipt!=='string'||!receipt.trim())throw new Error('Gönderim kabul kaydı gerekli.');
      return transaction(db=>{
        const result=db.prepare("UPDATE brief_messages SET state='accepted',receipt=?,error=NULL WHERE batch=? AND position=? AND lease=? AND state='sending'")
          .run(receipt,claim.batch,claim.position,claim.lease);
        if(result.changes!==1)throw new Error('Özet gönderim kaydı değişti.');
      });
    },
    hold(claim,error) {
      return transaction(db=>db.prepare("UPDATE brief_messages SET state='uncertain',error=? WHERE batch=? AND position=? AND lease=? AND state='sending'")
        .run(String(error?.message || error),claim.batch,claim.position,claim.lease).changes===1);
    },
    queue(clock=Date.now()) {
      return transaction(db=>{
        db.prepare("UPDATE brief_messages SET state='uncertain',error=? WHERE state='sending' AND lease_until<=?")
          .run('Kesintiye uğrayan gönderim; sağlayıcı kaydı incelenmeli.',clock);
        return db.prepare(`SELECT b.week,b.email,b.manifest,m.*,r.actor,r.action,r.note,r.reviewed_at
          FROM brief_messages m JOIN brief_batches b ON b.id=m.batch
          LEFT JOIN brief_reviews r ON r.batch=m.batch AND r.position=m.position
          WHERE m.state!='accepted' OR r.action IS NOT NULL
          ORDER BY b.week DESC,b.email,m.position`).all().map(row=>{
          const message=JSON.parse(row.manifest)[row.position];
          return {id:`${row.batch}:${row.position}`,to:message.to || row.email,
            subject:`Haftalık özet · ${row.week} · ${message.channel === 'telegram' ? 'Telegram' : 'E-posta'} · Mesaj ${row.position+1}`,
            state:row.action==='confirmed_sent'?'sent_manual':row.state,error:row.error,providerId:row.receipt,
            review:row.action?{actor:row.actor,action:row.action,note:row.note,at:row.reviewed_at}:null};
        });
      });
    },
    resolve(id,actor,input) {
      const match=typeof id==='string' && /^([a-f0-9]{64}):(\d+)$/.exec(id);
      if(!match || !Number.isSafeInteger(Number(match[2])) || typeof actor!=='string' || !actor.trim() ||
        !['confirmed_sent','skip'].includes(input?.action) || typeof input.note!=='string' || input.note.trim().length<20 || input.note.length>2000)
        throw new Error('Karar ve en az 20 karakterlik kontrol açıklaması gerekli.');
      const sent=input.action==='confirmed_sent';
      if(sent && (input.confirmed!==true || typeof input.providerId!=='string' || !input.providerId.trim() || input.providerId.length>200))
        throw new Error('Sağlayıcı gönderim kimliği ve kontrol onayı gerekli.');
      const batch=match[1],position=Number(match[2]);
      return transaction(db=>{
        const row=db.prepare("SELECT state FROM brief_messages WHERE batch=? AND position=?").get(batch,position);
        if(row?.state!=='uncertain')throw Object.assign(new Error('Kayıt artık inceleme beklemiyor. Listeyi yenileyin.'),{status:409});
        db.prepare('INSERT INTO brief_reviews VALUES (?,?,?,?,?,?)').run(batch,position,actor,input.action,input.note.trim(),new Date().toISOString());
        db.prepare('UPDATE brief_messages SET state=?,receipt=?,error=NULL WHERE batch=? AND position=?')
          .run(sent?'accepted':'skipped',sent?input.providerId.trim():null,batch,position);
        return {id,state:sent?'sent_manual':'skipped'};
      });
    },
    inspect() {
      return transaction(db=>db.prepare('SELECT b.week,b.email,m.* FROM brief_messages m JOIN brief_batches b ON b.id=m.batch ORDER BY b.week DESC,b.email,m.position').all());
    },
  };
}