// builds cross-company relationship graph from company_facts rows where type = 'relationship'

const https = require("https");
const http = require("http");

const VALID_TYPES = ["supplier", "customer", "competitor", "partner", "investor", "dependency"];

const KEYWORD_MAP = [
  ["manufactur", "supplier"],
  ["suppli", "supplier"],
  ["distribut", "supplier"],
  ["compet", "competitor"],
  ["rival", "competitor"],
  ["invest", "investor"],
  ["fund", "investor"],
  ["backer", "investor"],
  ["customer", "customer"],
  ["client", "customer"],
  ["depend", "dependency"],
  ["partner", "partner"],
  ["collaborat", "partner"],
  ["joint", "partner"],
];

const RECIPROCAL = {
  supplier: "customer",
  customer: "supplier",
  competitor: "competitor",
  partner: "partner",
  investor: "dependency",
  dependency: "investor",
};


function parseRelationshipType(rawType) {
  const t = (rawType || "").toLowerCase().trim();

  if (VALID_TYPES.includes(t)) return t;

  for (const [kw, mapped] of KEYWORD_MAP) {
    if (t.includes(kw)) return mapped;
  }

  return "partner";
}


function parseClaim(claim) {
  // format from consolidationWorker: "entity is a type"
  const parts = claim.split(" is a ");
  if (parts.length < 2) return null;

  const toEntity = parts[0].trim();
  const rawType = parts.slice(1).join(" is a ").trim();

  if (!toEntity || !rawType) return null;

  return {
    toEntity,
    relationshipType: parseRelationshipType(rawType),
  };
}


function normalizeName(s) {
  return (s || "").toLowerCase().replace(/\./g, "").replace(/\s+/g, " ").trim();
}


// stopwords to skip when building LIKE terms
const SKIP_WORDS = new Set(["the", "and", "of", "a", "an", "inc", "corp", "ltd", "llc", "co", "plus"]);


// ask LLM to match entity against a list of candidate company names
// returns the matched company name or null
async function llmResolveEntity(entity, candidates, llmConfig) {
  if (!candidates.length) return null;

  const list = candidates.map((c, i) => `${i + 1}. ${c.name}`).join("\n");

  const prompt = `Which of the following companies, if any, does "${entity}" refer to?

${list}

Reply with just the number of the match, or "none" if none apply. No explanation.`;

  const body = JSON.stringify({
    model: llmConfig.cheapModel || llmConfig.llmModel || llmConfig.model,
    messages: [{ role: "user", content: prompt }],
    temperature: 0,
  });

  const url = new URL("https://openrouter.ai/api/v1/chat/completions");
  let responseText;

  try {
    responseText = await httpPost(url, body, {
      "Content-Type": "application/json",
      "Authorization": `Bearer ${llmConfig.apiKey || ""}`,
    });
  } catch (err) {
    console.warn("[graph] LLM resolve failed:", err.message);
    return null;
  }

  let parsed;
  try { parsed = JSON.parse(responseText); } catch (_) { return null; }

  const content = (parsed.choices?.[0]?.message?.content || "").trim().toLowerCase();

  if (content === "none" || content === "0") return null;

  const idx = parseInt(content, 10);
  if (!isNaN(idx) && idx >= 1 && idx <= candidates.length) {
    return candidates[idx - 1];
  }

  return null;
}


// pre-resolves all unique unmatched entities via LIKE + LLM before the transaction
async function buildResolutionCache(facts, intelligenceDb, llmConfig) {

  const exactCache = new Map(); // entity -> company row (from exact match)
  const llmCache = new Map();   // entity -> company row or null (from LLM)

  const allCompanies = intelligenceDb.prepare("SELECT * FROM tracked_companies").all();

  // build a quick exact-match lookup
  const byNormalizedName = new Map();
  const byTicker = new Map();
  const byAlias = new Map();

  for (const co of allCompanies) {
    byNormalizedName.set(normalizeName(co.name), co);
    if (co.ticker) byTicker.set(co.ticker.toLowerCase(), co);

    let aliases = [];
    try { aliases = JSON.parse(co.aliases || "[]"); } catch (_) {}
    for (const alias of aliases) byAlias.set(normalizeName(alias), co);
  }

  const uniqueEntities = [...new Set(
    facts.map(f => parseClaim(f.claim)?.toEntity).filter(Boolean)
  )];

  const getCandidates = intelligenceDb.prepare(`
    SELECT * FROM tracked_companies WHERE name LIKE ? LIMIT 20
  `);

  for (const entity of uniqueEntities) {
    const needle = normalizeName(entity);

    // try exact match first
    const exact = byNormalizedName.get(needle) || byTicker.get(needle) || byAlias.get(needle);
    if (exact) {
      exactCache.set(entity, exact);
      continue;
    }

    // build candidate list via LIKE on each meaningful word
    const words = needle.split(" ").filter(w => w.length >= 3 && !SKIP_WORDS.has(w));
    if (!words.length) {
      llmCache.set(entity, null);
      continue;
    }

    const seen = new Map();
    for (const word of words) {
      const rows = getCandidates.all(`%${word}%`);
      for (const row of rows) {
        if (!seen.has(row.id)) seen.set(row.id, row);
      }
    }

    const candidates = [...seen.values()].slice(0, 20);

    const resolved = await llmResolveEntity(entity, candidates, llmConfig);
    llmCache.set(entity, resolved || null);

    if (resolved) {
      console.log(`[graph] LLM resolved "${entity}" -> ${resolved.name}`);
    }
  }

  return { exactCache, llmCache };
}


function resolveFromCache(entity, exactCache, llmCache) {
  return exactCache.get(entity) ?? llmCache.get(entity) ?? null;
}


function confidenceFromCount(count) {
  if (count >= 8) return "very_high";
  if (count >= 4) return "high";
  if (count >= 2) return "medium";
  return "low";
}


function mergeEventIds(existingJson, newJson) {
  let existing = [];
  let incoming = [];

  try { existing = JSON.parse(existingJson || "[]"); } catch (_) {}
  try { incoming = JSON.parse(newJson || "[]"); } catch (_) {}

  const merged = [...new Set([...existing, ...incoming])];
  return JSON.stringify(merged);
}


async function runGraphWorker(archiveDb, intelligenceDb, config) {
  const loopDelay = config.workers?.graphWorkerLoopDelayMs ?? 90000;
  const llmConfig = config.openRouter || {};

  const getRelationshipFacts = intelligenceDb.prepare(`
    SELECT * FROM company_facts WHERE type = 'relationship'
  `);

  const recordEvents = intelligenceDb.prepare(
    `INSERT INTO worker_events (worker) VALUES ('graph')`
  );
  const pruneEvents = intelligenceDb.prepare(
    `DELETE FROM worker_events WHERE worker = 'graph' AND completed_at < datetime('now', '-1 hour')`
  );

  const getCompanyById = intelligenceDb.prepare("SELECT * FROM tracked_companies WHERE id = ?");

  const getExistingRel = intelligenceDb.prepare(`
    SELECT * FROM company_relationships
    WHERE from_company_id = ? AND relationship_type = ? AND to_entity = ?
  `);

  const insertRel = intelligenceDb.prepare(`
    INSERT INTO company_relationships
      (from_company_id, relationship_type, to_entity, to_company_id, confidence, confirmation_count, first_seen_at, last_seen_at, supporting_event_ids)
    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
  `);

  const updateRel = intelligenceDb.prepare(`
    UPDATE company_relationships
    SET confirmation_count = ?,
        confidence = ?,
        last_seen_at = ?,
        supporting_event_ids = ?
    WHERE from_company_id = ? AND relationship_type = ? AND to_entity = ?
  `);

  const getExistingReciprocal = intelligenceDb.prepare(`
    SELECT id FROM company_relationships
    WHERE from_company_id = ? AND relationship_type = ? AND to_entity = ?
  `);

  const insertReciprocal = intelligenceDb.prepare(`
    INSERT OR IGNORE INTO company_relationships
      (from_company_id, relationship_type, to_entity, to_company_id, confidence, confirmation_count, first_seen_at, last_seen_at, supporting_event_ids)
    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
  `);


  while (true) {
    try {
      const facts = getRelationshipFacts.all();

      // resolve all entities before entering the transaction
      const { exactCache, llmCache } = await buildResolutionCache(facts, intelligenceDb, llmConfig);

      let upserted = 0;
      let reciprocals = 0;

      const processAll = intelligenceDb.transaction(() => {
        for (const fact of facts) {
          const parsed = parseClaim(fact.claim);
          if (!parsed) continue;

          const { toEntity, relationshipType } = parsed;

          const resolved = resolveFromCache(toEntity, exactCache, llmCache);
          const toCompanyId = resolved ? resolved.id : null;

          const existing = getExistingRel.get(fact.company_id, relationshipType, toEntity);
          const now = new Date().toISOString();

          let finalCount;
          let finalFirst;
          let finalLast;
          let finalEventIds;

          if (existing) {
            finalCount = fact.confirmation_count;
            finalFirst = existing.first_seen_at;
            finalLast = fact.last_seen_at || now;
            finalEventIds = mergeEventIds(existing.supporting_event_ids, fact.supporting_event_ids);

            updateRel.run(
              finalCount,
              confidenceFromCount(finalCount),
              finalLast,
              finalEventIds,
              fact.company_id,
              relationshipType,
              toEntity
            );
          } else {
            finalCount = fact.confirmation_count || 1;
            finalFirst = fact.first_seen_at || now;
            finalLast = fact.last_seen_at || now;
            finalEventIds = fact.supporting_event_ids || "[]";

            insertRel.run(
              fact.company_id,
              relationshipType,
              toEntity,
              toCompanyId,
              confidenceFromCount(finalCount),
              finalCount,
              finalFirst,
              finalLast,
              finalEventIds
            );
          }

          upserted++;


          // reciprocal edge — only where both companies are tracked
          if (toCompanyId) {
            const fromCompany = getCompanyById.get(fact.company_id);
            if (!fromCompany) continue;

            const recipType = RECIPROCAL[relationshipType] || "partner";
            const recipToEntity = fromCompany.name;

            const recipExists = getExistingReciprocal.get(toCompanyId, recipType, recipToEntity);

            if (!recipExists) {
              insertReciprocal.run(
                toCompanyId,
                recipType,
                recipToEntity,
                fact.company_id,
                confidenceFromCount(finalCount),
                finalCount,
                finalFirst,
                finalLast,
                finalEventIds
              );

              reciprocals++;
            }
          }
        }
      });

      processAll();

      if (upserted > 0) {
        const insertMany = intelligenceDb.transaction((n) => {
          for (let i = 0; i < n; i++) recordEvents.run();
        });
        insertMany(upserted);
        pruneEvents.run();
      }

      if (upserted > 0 || reciprocals > 0) {
        console.log(`[graph] cycle complete — ${upserted} edges upserted, ${reciprocals} reciprocals added`);
      } else {
        console.log("[graph] cycle complete — no new data");
      }

    } catch (err) {
      console.error("[graph] cycle error:", err.message);
    }

    await sleep(loopDelay);
  }
}


function httpPost(url, body, headers) {
  return new Promise((resolve, reject) => {
    const lib = url.protocol === "https:" ? https : http;

    const req = lib.request({
      hostname: url.hostname,
      port: url.port || (url.protocol === "https:" ? 443 : 80),
      path: url.pathname + url.search,
      method: "POST",
      headers: { ...headers, "Content-Length": Buffer.byteLength(body) },
    }, (res) => {
      let data = "";
      res.on("data", chunk => data += chunk);
      res.on("end", () => {
        if (res.statusCode >= 200 && res.statusCode < 300) resolve(data);
        else reject(new Error(`LLM ${res.statusCode}: ${data.slice(0, 300)}`));
      });
    });

    req.on("error", reject);
    req.write(body);
    req.end();
  });
}


function sleep(ms) {
  return new Promise(r => setTimeout(r, ms));
}

module.exports = { runGraphWorker };