import fs from "node:fs/promises";
import path from "node:path";
import os from "node:os";
import crypto from "node:crypto";

const HOOK_KEY = "task-board-realtime";
const DEFAULT_API_BASE = "http://127.0.0.1:3001";
const DEFAULT_MAX_REMEMBERED = 3000;
const DEFAULT_ADMIN_TOKEN = "dev-task-board-token";
const SESSION_TAIL_BYTES = 2 * 1024 * 1024;
const SESSION_USER_SCAN_LIMIT = 80;
const DEFERRED_RECONCILE_DELAYS_MS = [1600, 4800];

function nowIso() {
  return new Date().toISOString();
}

function safeTrim(value) {
  return typeof value === "string" ? value.trim() : "";
}

function oneLine(text) {
  return safeTrim(text).replace(/\s+/g, " ");
}

function truncate(text, maxChars) {
  if (!text) return "";
  if (text.length <= maxChars) return text;
  return `${text.slice(0, Math.max(1, maxChars - 1))}...`;
}

function stableHash(input) {
  return crypto.createHash("sha1").update(input).digest("hex").slice(0, 12);
}

function resolveStateDir() {
  const explicit = safeTrim(process.env.OPENCLAW_STATE_DIR);
  if (explicit) return explicit;
  return path.join(os.homedir(), ".openclaw");
}

function resolveConfigPath(stateDir) {
  const explicit = safeTrim(process.env.OPENCLAW_CONFIG_PATH);
  if (explicit) return explicit;
  return path.join(stateDir, "openclaw.json");
}

async function readJson(filePath, fallback) {
  try {
    const raw = await fs.readFile(filePath, "utf8");
    return JSON.parse(raw);
  } catch {
    return fallback;
  }
}

async function writeJsonAtomic(filePath, payload) {
  await fs.mkdir(path.dirname(filePath), { recursive: true });
  const tempPath = `${filePath}.${process.pid}.${Date.now()}.tmp`;
  await fs.writeFile(tempPath, `${JSON.stringify(payload, null, 2)}\n`, "utf8");
  await fs.rename(tempPath, filePath);
}

async function appendLog(stateDir, message) {
  try {
    const logPath = path.join(stateDir, "logs", "task-board-realtime.log");
    await fs.mkdir(path.dirname(logPath), { recursive: true });
    await fs.appendFile(logPath, `[${nowIso()}] ${message}\n`, "utf8");
  } catch {
    // Never fail hook execution on logging errors.
  }
}

function resolveHookConfig(config, stateDir) {
  const workspaceDir =
    safeTrim(config?.agents?.defaults?.workspace) ||
    safeTrim(config?.workspace?.dir) ||
    path.join(stateDir, "workspace");

  const cfg = config?.hooks?.internal?.entries?.[HOOK_KEY] ?? {};
  const apiBaseUrl =
    safeTrim(cfg.apiBaseUrl) ||
    safeTrim(process.env.TASK_BOARD_API_BASE) ||
    DEFAULT_API_BASE;
  const adminToken =
    safeTrim(cfg.adminToken) ||
    safeTrim(process.env.TASK_BOARD_ADMIN_TOKEN) ||
    DEFAULT_ADMIN_TOKEN;
  const stateFileRaw = safeTrim(cfg.stateFile);
  const stateFile = stateFileRaw
    ? path.isAbsolute(stateFileRaw)
      ? stateFileRaw
      : path.join(workspaceDir, stateFileRaw)
    : path.join(workspaceDir, "task-board", ".sync-state.json");

  const maxRemembered = Number.isFinite(cfg.maxRememberedMessages)
    ? Math.max(200, Math.floor(cfg.maxRememberedMessages))
    : DEFAULT_MAX_REMEMBERED;

  return {
    workspaceDir,
    apiBaseUrl: apiBaseUrl.replace(/\/+$/, ""),
    stateFile,
    adminToken,
    ignoreSlashCommands: cfg.ignoreSlashCommands !== false,
    maxRemembered,
  };
}

function normalizeState(state) {
  const safe = state && typeof state === "object" ? state : {};
  return {
    version: 1,
    sessions: safe.sessions && typeof safe.sessions === "object" ? safe.sessions : {},
    counters: safe.counters && typeof safe.counters === "object" ? safe.counters : {},
    messages: safe.messages && typeof safe.messages === "object" ? safe.messages : {},
    updatedAt: safeTrim(safe.updatedAt) || nowIso(),
  };
}

function cleanupSeenMessages(state, maxRemembered) {
  const entries = Object.entries(state.messages).sort((a, b) => {
    const ta = Date.parse(a[1]) || 0;
    const tb = Date.parse(b[1]) || 0;
    return tb - ta;
  });
  if (entries.length <= maxRemembered) return;
  for (const [key] of entries.slice(maxRemembered)) {
    delete state.messages[key];
  }
}

function toIsoFromEvent(event) {
  const contextTs = Number(event?.context?.timestamp);
  if (Number.isFinite(contextTs)) {
    return new Date(contextTs).toISOString();
  }
  if (event?.timestamp instanceof Date && Number.isFinite(event.timestamp.getTime())) {
    return event.timestamp.toISOString();
  }
  return nowIso();
}

async function requestJson(apiBaseUrl, urlPath, method = "GET", payload, extraHeaders = {}) {
  const controller = new AbortController();
  const timer = setTimeout(() => controller.abort(), 8000);

  try {
    const response = await fetch(`${apiBaseUrl}${urlPath}`, {
      method,
      headers: {
        "Content-Type": "application/json",
        ...extraHeaders,
      },
      body: payload === undefined ? undefined : JSON.stringify(payload),
      signal: controller.signal,
    });
    const data = await response.json().catch(() => ({}));
    if (!response.ok) {
      throw new Error(`${method} ${urlPath} failed: ${response.status} ${data.error || ""}`.trim());
    }
    return data;
  } finally {
    clearTimeout(timer);
  }
}

function buildMessageDedupKey(event, content, isoAt) {
  const sessionKey = safeTrim(event?.sessionKey) || "unknown-session";
  const messageId = safeTrim(event?.context?.messageId);
  if (messageId) {
    return `${sessionKey}::${messageId}`;
  }
  return `${sessionKey}::${stableHash(`${content}::${isoAt}`)}`;
}

function resolveAgentId(event) {
  const fromContext = safeTrim(event?.context?.agentId);
  const fromSessionKey = safeTrim(event?.sessionKey).split(":")[1] || "";
  return fromContext || fromSessionKey || "main";
}

async function resolveSessionIdFromRegistry(stateDir, event) {
  const sessionKey = safeTrim(event?.sessionKey);
  if (!sessionKey) return "";

  const agentId = resolveAgentId(event);
  const registryPath = path.join(stateDir, "agents", agentId, "sessions", "sessions.json");
  const registry = await readJson(registryPath, {});

  const direct = registry?.[sessionKey];
  if (safeTrim(direct?.sessionId)) return safeTrim(direct.sessionId);

  const lowered = sessionKey.toLowerCase();
  const loweredMatch = registry?.[lowered];
  if (safeTrim(loweredMatch?.sessionId)) return safeTrim(loweredMatch.sessionId);

  return "";
}

async function resolveSessionTranscriptPath(stateDir, event) {
  const explicitSessionId = safeTrim(event?.context?.sessionId);
  const sessionId = explicitSessionId || (await resolveSessionIdFromRegistry(stateDir, event));
  if (!sessionId) return "";

  const agentId = resolveAgentId(event);
  const sessionsDir = path.join(stateDir, "agents", agentId, "sessions");
  const exactPath = path.join(sessionsDir, `${sessionId}.jsonl`);

  try {
    const entries = await fs.readdir(sessionsDir, { withFileTypes: true });
    const prefixed = entries
      .filter((entry) => entry.isFile())
      .map((entry) => entry.name)
      .filter((name) => name.startsWith(`${sessionId}-`) && name.endsWith(".jsonl"));

    const candidates = [path.basename(exactPath), ...prefixed];
    if (!candidates.length) return "";

    const withStats = await Promise.all(
      candidates.map(async (name) => {
        const fullPath = path.join(sessionsDir, name);
        try {
          const stat = await fs.stat(fullPath);
          return { fullPath, mtimeMs: Number(stat.mtimeMs) || 0 };
        } catch {
          return null;
        }
      }),
    );
    const existing = withStats.filter(Boolean);
    if (!existing.length) return "";
    existing.sort((a, b) => b.mtimeMs - a.mtimeMs);
    return existing[0].fullPath;
  } catch {
    return "";
  }
}

function extractTextFromMessageContent(content) {
  if (!Array.isArray(content)) return "";
  const parts = [];
  for (const chunk of content) {
    if (!chunk || typeof chunk !== "object") continue;
    if (chunk.type === "text" && typeof chunk.text === "string") {
      parts.push(chunk.text);
    }
  }
  return oneLine(parts.join("\n"));
}

async function readFileTail(filePath, maxBytes) {
  const stat = await fs.stat(filePath);
  const size = Number(stat.size) || 0;
  const start = Math.max(0, size - maxBytes);
  const bytesToRead = size - start;
  if (bytesToRead <= 0) return "";

  const file = await fs.open(filePath, "r");
  try {
    const buffer = Buffer.alloc(bytesToRead);
    await file.read(buffer, 0, bytesToRead, start);
    return buffer.toString("utf8");
  } finally {
    await file.close();
  }
}

async function extractUserMessagesFromTranscript(stateDir, event) {
  const transcriptPath = await resolveSessionTranscriptPath(stateDir, event);
  if (!transcriptPath) return [];

  try {
    const text = await readFileTail(transcriptPath, SESSION_TAIL_BYTES);
    const lines = text.split("\n").map((line) => line.trim()).filter(Boolean);
    const messages = [];
    const seen = new Set();

    for (let i = 0; i < lines.length; i += 1) {
      const line = lines[i];
      let row;
      try {
        row = JSON.parse(line);
      } catch {
        continue;
      }

      if (row?.type !== "message") continue;
      if (row?.message?.role !== "user") continue;

      const content = extractTextFromMessageContent(row?.message?.content);
      if (!content) continue;

      const timestamp = Date.parse(row.timestamp || "");
      const id = safeTrim(row.id);
      const fallbackId = stableHash(`${safeTrim(row.timestamp)}::${content}`);
      const messageId = id || `bootstrap-${fallbackId}`;
      if (seen.has(messageId)) continue;
      seen.add(messageId);

      messages.push({
        messageId,
        content,
        timestamp: Number.isFinite(timestamp) ? timestamp : Date.now(),
      });
    }

    if (messages.length <= SESSION_USER_SCAN_LIMIT) {
      return messages;
    }
    return messages.slice(messages.length - SESSION_USER_SCAN_LIMIT);
  } catch (error) {
    await appendLog(stateDir, `WARN transcript parse failed: ${String(error.message || error)}`);
  }

  return [];
}

async function closeConversationIfPresent(event, runtime, state) {
  const sessionKey = safeTrim(event?.sessionKey);
  if (!sessionKey) return false;

  const sessionState = state.sessions[sessionKey];
  if (!sessionState?.rootTaskId) return false;

  const endTime = toIsoFromEvent(event);
  try {
    await requestJson(
      runtime.apiBaseUrl,
      `/api/admin/nodes/${encodeURIComponent(sessionState.rootTaskId)}`,
      "PUT",
      {
      status: "completed",
      timestamps: {
        completed: endTime,
      },
      notes: oneLine(`${safeTrim(sessionState.notes) || ""} Conversation closed by /${event.action}.`),
      },
      {
        Authorization: `Bearer ${runtime.adminToken}`,
      },
    );
  } catch (error) {
    await appendLog(runtime.stateDir, `WARN close root failed session=${sessionKey}: ${String(error.message || error)}`);
  }

  const lastIndex = Number(sessionState.index) || Number(state.counters[sessionKey]) || 0;
  state.counters[sessionKey] = Math.max(1, lastIndex);
  delete state.sessions[sessionKey];
  state.updatedAt = nowIso();
  return true;
}

async function ensureRootTask(event, runtime, state) {
  const sessionKey = safeTrim(event?.sessionKey);
  if (!sessionKey) return null;

  const existing = state.sessions[sessionKey];
  if (existing?.rootTaskId) {
    return existing;
  }

  const index = (Number(state.counters[sessionKey]) || 0) + 1;
  const preview = truncate(oneLine(event?.context?.content || ""), 26) || "new conversation";
  const rootName = `Conversation #${index} · ${preview}`;
  const startedAt = toIsoFromEvent(event);

  const created = await requestJson(
    runtime.apiBaseUrl,
    "/api/admin/nodes",
    "POST",
    {
      conversationId: sessionKey,
    name: rootName,
      nodeType: "prompt",
    status: "in-progress",
      content: oneLine(event?.context?.content || ""),
      timestamps: {
        created: startedAt,
        started: startedAt,
      },
    plannedApproach: "Auto-synced from OpenClaw conversation events.",
    notes: `sessionKey=${sessionKey}`,
    },
    {
      Authorization: `Bearer ${runtime.adminToken}`,
    },
  );

  const sessionState = {
    rootTaskId: String(created.id),
    index,
    startedAt,
    notes: `sessionKey=${sessionKey}`,
  };
  state.sessions[sessionKey] = sessionState;
  state.updatedAt = nowIso();
  return sessionState;
}

async function appendMessageChild(event, runtime, state, sessionState) {
  const content = oneLine(event?.context?.content || "");
  if (!content) return false;
  if (runtime.ignoreSlashCommands && content.startsWith("/")) return false;

  const atIso = toIsoFromEvent(event);
  const dedupKey = buildMessageDedupKey(event, content, atIso);
  if (state.messages[dedupKey]) return false;

  const channelId = safeTrim(event?.context?.channelId) || "unknown";
  const messageId = safeTrim(event?.context?.messageId) || "n/a";
  const childName = `Turn · ${truncate(content, 36)}`;
  const notes = [
    `content=${content}`,
    `messageId=${messageId}`,
    `channelId=${channelId}`,
    `sessionKey=${safeTrim(event?.sessionKey) || "unknown"}`,
  ].join("\n");

  await requestJson(
    runtime.apiBaseUrl,
    "/api/admin/nodes",
    "POST",
    {
      conversationId: safeTrim(event?.sessionKey) || "unknown-session",
    name: childName,
    parentId: sessionState.rootTaskId,
      nodeType: "thought",
    status: "completed",
      content,
      timestamps: {
        created: atIso,
        started: atIso,
        completed: atIso,
      },
    notes,
    },
    {
      Authorization: `Bearer ${runtime.adminToken}`,
    },
  );

  state.messages[dedupKey] = nowIso();
  cleanupSeenMessages(state, runtime.maxRemembered);
  state.updatedAt = nowIso();
  return true;
}

async function reconcileTranscriptMessages(event, runtime, state, stateDir) {
  let createdAny = false;
  const transcriptMessages = await extractUserMessagesFromTranscript(stateDir, event);
  if (!transcriptMessages.length) return false;

  for (const item of transcriptMessages) {
    const syntheticEvent = {
      ...event,
      type: "message",
      action: "received",
      context: {
        ...(event?.context || {}),
        content: item.content,
        messageId: item.messageId,
        timestamp: item.timestamp,
        channelId: "agent-bootstrap",
      },
    };

    const sessionState = await ensureRootTask(syntheticEvent, runtime, state);
    if (!sessionState) continue;

    const created = await appendMessageChild(syntheticEvent, runtime, state, sessionState);
    createdAny = createdAny || created;
  }

  return createdAny;
}

function scheduleDeferredReconcile(event, runtime) {
  if (event?.context?._taskBoardDeferred) return;

  for (const delayMs of DEFERRED_RECONCILE_DELAYS_MS) {
    const timer = setTimeout(() => {
      void (async () => {
        try {
          const deferredState = normalizeState(await readJson(runtime.stateFile, {}));
          const deferredEvent = {
            ...event,
            context: {
              ...(event?.context || {}),
              _taskBoardDeferred: true,
            },
          };
          const createdAny = await reconcileTranscriptMessages(deferredEvent, runtime, deferredState, runtime.stateDir);
          if (createdAny) {
            await writeJsonAtomic(runtime.stateFile, deferredState);
          }
        } catch (error) {
          const message = error instanceof Error ? error.message : String(error);
          await appendLog(runtime.stateDir, `WARN deferred reconcile failed: ${message}`);
        }
      })();
    }, delayMs);
    if (typeof timer?.unref === "function") {
      timer.unref();
    }
  }
}

export default async function taskBoardRealtimeHook(event) {
  const stateDir = resolveStateDir();
  const configPath = resolveConfigPath(stateDir);
  const config = await readJson(configPath, {});
  const runtime = resolveHookConfig(config, stateDir);
  runtime.stateDir = stateDir;

  const state = normalizeState(await readJson(runtime.stateFile, {}));

  try {
    if (event?.type === "command" && (event?.action === "new" || event?.action === "reset")) {
      const changed = await closeConversationIfPresent(event, runtime, state);
      if (changed) {
        await writeJsonAtomic(runtime.stateFile, state);
      }
      return;
    }

    const isMessageReceived = event?.type === "message" && event?.action === "received";
    const shouldScanTranscript =
      (event?.type === "agent" && event?.action === "bootstrap") ||
      (event?.type === "message" && event?.action === "sent") ||
      (event?.type === "command" && event?.action === "stop");

    if (!isMessageReceived) {
      if (!shouldScanTranscript) {
        return;
      }

      const createdAny = await reconcileTranscriptMessages(event, runtime, state, stateDir);
      if (createdAny) {
        await writeJsonAtomic(runtime.stateFile, state);
      }
      scheduleDeferredReconcile(event, runtime);
      return;
    }

    const sessionState = await ensureRootTask(event, runtime, state);
    if (!sessionState) return;

    const created = await appendMessageChild(event, runtime, state, sessionState);
    if (created) {
      await writeJsonAtomic(runtime.stateFile, state);
    }
  } catch (error) {
    const message = error instanceof Error ? error.message : String(error);
    await appendLog(stateDir, `ERROR event=${event?.type || "unknown"}:${event?.action || "unknown"} ${message}`);
  }
}