/**
 * Agent Forum v4 - Historian Agent
 *
 * Role: Prevent regression and historical repetition.
 * Inputs: sqlite-vec, Git Notes
 * Outputs: Contextual injection (passing historical context to other agents/pipeline)
 */

import { parseArgs } from "https://deno.land/std@0.224.0/cli/parse_args.ts";
import { Database } from "jsr:@db/sqlite";
import * as sqliteVec from "npm:sqlite-vec";

async function runCommand(
  cmd: string,
  args: string[],
): Promise<{ code: number; stdout: string; stderr: string }> {
  const command = new Deno.Command(cmd, {
    args,
    stdout: "piped",
    stderr: "piped",
  });
  const { code, stdout, stderr } = await command.output();
  const decoder = new TextDecoder();
  return {
    code,
    stdout: decoder.decode(stdout).trim(),
    stderr: decoder.decode(stderr).trim(),
  };
}

/**
 * Fetches Git Notes for a specific namespace across the git history.
 */
async function fetchGitNotes(namespace: string): Promise<string[]> {
  console.log(`   Fetching Git Notes for namespace: ${namespace}...`);
  // Use git log to show notes for the specified namespace
  const cmd = await runCommand("git", [
    "log",
    `--show-notes=${namespace}`,
    "--pretty=format:%N",
  ]);

  if (cmd.code !== 0 || !cmd.stdout) {
    return [];
  }

  // Split by newlines and filter out empty lines (since %N can return empty if no note)
  const lines = cmd.stdout.split("\n").filter((line) => line.trim() !== "");
  return lines;
}

async function gatherHistoricalContext() {
  console.log("-> Historian Agent: Gathering historical context...");

  // 1. Construct search string from file changes
  const diffCmd = await runCommand("git", ["diff", "--name-only", "HEAD~1", "HEAD"]);
  const searchVectorString = diffCmd.stdout.split("\n").filter(Boolean).join(" ");
  console.log(`   Search vector string derived from diff: "${searchVectorString}"`);

  // 2. Fetch from Vector DB
  console.log("   Extracting SQLite databases from meta-state branch...");

  const extractedVectors: string[] = [];
  try {
    const checkDocs = await runCommand("git", ["ls-tree", "meta-state", "docs_graph.sqlite"]);
    const checkTelemetry = await runCommand("git", ["ls-tree", "meta-state", "telemetry_graph.sqlite"]);

    // Dummy vector string based on search string for PoC query, normally we would generate an embedding for searchVectorString
    const dummyVector = new Uint8Array(new Float32Array([0,0,0]).buffer);

    if (checkDocs.code === 0 && checkDocs.stdout.trim() !== "") {
      const tempDbPath = await Deno.makeTempFile({ suffix: ".sqlite" });
      const dbFile = await Deno.open(tempDbPath, { write: true });
      const cmd = new Deno.Command("git", {
        args: ["show", "meta-state:docs_graph.sqlite"],
        stdout: "piped"
      });
      const output = await cmd.output();
      await dbFile.write(output.stdout);
      dbFile.close();

      const db = new Database(tempDbPath);
      db.enableLoadExtension = true;
      sqliteVec.load(db);
      db.enableLoadExtension = false;

      try {
        const results = db.prepare("SELECT text, vec_distance_cosine(embedding, ?) as similarity FROM docs ORDER BY similarity DESC LIMIT 3").all(dummyVector);
        for (const row of results) {
          extractedVectors.push(`Doc2Vec: ${row.text}`);
        }
      } catch (e) {
        console.warn("   ⚠️ Could not query docs_graph.sqlite:", e);
      }
      db.close();
      await Deno.remove(tempDbPath);
    }

    if (checkTelemetry.code === 0 && checkTelemetry.stdout.trim() !== "") {
      const tempDbPath = await Deno.makeTempFile({ suffix: ".sqlite" });
      const dbFile = await Deno.open(tempDbPath, { write: true });
      const cmd = new Deno.Command("git", {
        args: ["show", "meta-state:telemetry_graph.sqlite"],
        stdout: "piped"
      });
      const output = await cmd.output();
      await dbFile.write(output.stdout);
      dbFile.close();

      const db = new Database(tempDbPath);
      db.enableLoadExtension = true;
      sqliteVec.load(db);
      db.enableLoadExtension = false;

      try {
        // Assume telemetry table for PoC purposes
        const results = db.prepare("SELECT text, vec_distance_cosine(embedding, ?) as similarity FROM telemetry ORDER BY similarity DESC LIMIT 3").all(dummyVector);
        for (const row of results) {
          extractedVectors.push(`Telemetry2Vec: ${row.text}`);
        }
      } catch (e) {
        console.warn("   ⚠️ Could not query telemetry_graph.sqlite:", e);
      }
      db.close();
      await Deno.remove(tempDbPath);
    }
  } catch (e) {
     console.warn("   ⚠️ Failed to query sqlite db:", e);
  }

  // 3. Fetch Git Notes (Reasoning, Telemetry, etc.)
  const reasoningNotes = await fetchGitNotes("reasoning");
  const aiNotes = await fetchGitNotes("ai");

  const combinedContext = {
    agent: "Historian",
    timestamp: Date.now(),
    extractedVectors: extractedVectors.length ? extractedVectors : ["No historical vector matches found."],
    historicalNotes: [...reasoningNotes, ...aiNotes],
    directive: "Ensure new Coder implementations avoid previously failed architectural patterns.",
  };

  console.log("-> Historian Agent: Context gathered successfully.");

  // Provide contextual injection (e.g., via writing to a specific Git Note for the Coder)
  const jsonString = JSON.stringify(combinedContext);
  const ref = `refs/notes/historical_context`;

  const cmd = await runCommand("git", [
    "notes",
    "--ref",
    ref,
    "add",
    "-f",
    "-m",
    jsonString,
    "HEAD",
  ]);

  if (cmd.code !== 0) {
    console.error(
      `⚠️ Failed to inject historical context to Git Notes:`,
      cmd.stderr,
    );
  } else {
    console.log(
      "-> Contextual injection written to Git Notes (refs/notes/historical_context).",
    );
  }
}

async function main() {
  const args = parseArgs(Deno.args, {
    boolean: ["run"],
  });

  if (args["run"]) {
    await gatherHistoricalContext();
  } else {
    console.log("Historian Agent installed. Run with --run flag.");
  }
}

if (import.meta.main) {
  await main();
}