import { lookupContextTokens } from "../agents/context.js";
import { DEFAULT_CONTEXT_TOKENS, DEFAULT_MODEL, DEFAULT_PROVIDER } from "../agents/defaults.js";
import { resolveConfiguredModelRef } from "../agents/model-selection.js";
import { loadConfig } from "../config/config.js";
import {
  loadSessionStore,
  resolveMainSessionKey,
  resolveStorePath,
  type SessionEntry,
} from "../config/sessions.js";
import { listAgentsForGateway } from "../gateway/session-utils.js";
import { buildChannelSummary } from "../infra/channel-summary.js";
import { resolveHeartbeatSummaryForAgent } from "../infra/heartbeat-runner.js";
import { peekSystemEvents } from "../infra/system-events.js";
import { parseAgentSessionKey } from "../routing/session-key.js";
import { resolveLinkChannelContext } from "./status.link-channel.js";
import type { HeartbeatStatus, SessionStatus, StatusSummary } from "./status.types.js";

const classifyKey = (key: string, entry?: SessionEntry): SessionStatus["kind"] => {
  if (key === "global") return "global";
  if (key === "unknown") return "unknown";
  if (entry?.chatType === "group" || entry?.chatType === "channel") {
    return "group";
  }
  if (key.includes(":group:") || key.includes(":channel:")) {
    return "group";
  }
  return "direct";
};

const buildFlags = (entry?: SessionEntry): string[] => {
  if (!entry) return [];
  const flags: string[] = [];
  const think = entry?.thinkingLevel;
  if (typeof think === "string" && think.length > 0) flags.push(`think:${think}`);
  const verbose = entry?.verboseLevel;
  if (typeof verbose === "string" && verbose.length > 0) flags.push(`verbose:${verbose}`);
  const reasoning = entry?.reasoningLevel;
  if (typeof reasoning === "string" && reasoning.length > 0) flags.push(`reasoning:${reasoning}`);
  const elevated = entry?.elevatedLevel;
  if (typeof elevated === "string" && elevated.length > 0) flags.push(`elevated:${elevated}`);
  if (entry?.systemSent) flags.push("system");
  if (entry?.abortedLastRun) flags.push("aborted");
  const sessionId = entry?.sessionId as unknown;
  if (typeof sessionId === "string" && sessionId.length > 0) flags.push(`id:${sessionId}`);
  return flags;
};

export async function getStatusSummary(): Promise<StatusSummary> {
  const cfg = loadConfig();
  const linkContext = await resolveLinkChannelContext(cfg);
  const agentList = listAgentsForGateway(cfg);
  const heartbeatAgents: HeartbeatStatus[] = agentList.agents.map((agent) => {
    const summary = resolveHeartbeatSummaryForAgent(cfg, agent.id);
    return {
      agentId: agent.id,
      enabled: summary.enabled,
      every: summary.every,
      everyMs: summary.everyMs,
    } satisfies HeartbeatStatus;
  });
  const channelSummary = await buildChannelSummary(cfg, {
    colorize: true,
    includeAllowFrom: true,
  });
  const mainSessionKey = resolveMainSessionKey(cfg);
  const queuedSystemEvents = peekSystemEvents(mainSessionKey);

  const resolved = resolveConfiguredModelRef({
    cfg,
    defaultProvider: DEFAULT_PROVIDER,
    defaultModel: DEFAULT_MODEL,
  });
  const configModel = resolved.model ?? DEFAULT_MODEL;
  const configContextTokens =
    cfg.agents?.defaults?.contextTokens ??
    lookupContextTokens(configModel) ??
    DEFAULT_CONTEXT_TOKENS;

  const now = Date.now();
  const storeCache = new Map<string, Record<string, SessionEntry | undefined>>();
  const loadStore = (storePath: string) => {
    const cached = storeCache.get(storePath);
    if (cached) return cached;
    const store = loadSessionStore(storePath);
    storeCache.set(storePath, store);
    return store;
  };
  const buildSessionRows = (
    store: Record<string, SessionEntry | undefined>,
    opts: { agentIdOverride?: string } = {},
  ) =>
    Object.entries(store)
      .filter(([key]) => key !== "global" && key !== "unknown")
      .map(([key, entry]) => {
        const updatedAt = entry?.updatedAt ?? null;
        const age = updatedAt ? now - updatedAt : null;
        const model = entry?.model ?? configModel ?? null;
        const contextTokens =
          entry?.contextTokens ?? lookupContextTokens(model) ?? configContextTokens ?? null;
        const input = entry?.inputTokens ?? 0;
        const output = entry?.outputTokens ?? 0;
        const total = entry?.totalTokens ?? input + output;
        const remaining = contextTokens != null ? Math.max(0, contextTokens - total) : null;
        const pct =
          contextTokens && contextTokens > 0
            ? Math.min(999, Math.round((total / contextTokens) * 100))
            : null;
        const parsedAgentId = parseAgentSessionKey(key)?.agentId;
        const agentId = opts.agentIdOverride ?? parsedAgentId;

        return {
          agentId,
          key,
          kind: classifyKey(key, entry),
          sessionId: entry?.sessionId,
          updatedAt,
          age,
          thinkingLevel: entry?.thinkingLevel,
          verboseLevel: entry?.verboseLevel,
          reasoningLevel: entry?.reasoningLevel,
          elevatedLevel: entry?.elevatedLevel,
          systemSent: entry?.systemSent,
          abortedLastRun: entry?.abortedLastRun,
          inputTokens: entry?.inputTokens,
          outputTokens: entry?.outputTokens,
          totalTokens: total ?? null,
          remainingTokens: remaining,
          percentUsed: pct,
          model,
          contextTokens,
          flags: buildFlags(entry),
        } satisfies SessionStatus;
      })
      .sort((a, b) => (b.updatedAt ?? 0) - (a.updatedAt ?? 0));

  const paths = new Set<string>();
  const byAgent = agentList.agents.map((agent) => {
    const storePath = resolveStorePath(cfg.session?.store, { agentId: agent.id });
    paths.add(storePath);
    const store = loadStore(storePath);
    const sessions = buildSessionRows(store, { agentIdOverride: agent.id });
    return {
      agentId: agent.id,
      path: storePath,
      count: sessions.length,
      recent: sessions.slice(0, 10),
    };
  });

  const allSessions = Array.from(paths)
    .flatMap((storePath) => buildSessionRows(loadStore(storePath)))
    .sort((a, b) => (b.updatedAt ?? 0) - (a.updatedAt ?? 0));
  const recent = allSessions.slice(0, 10);
  const totalSessions = allSessions.length;

  return {
    linkChannel: linkContext
      ? {
          id: linkContext.plugin.id,
          label: linkContext.plugin.meta.label ?? "Channel",
          linked: linkContext.linked,
          authAgeMs: linkContext.authAgeMs,
        }
      : undefined,
    heartbeat: {
      defaultAgentId: agentList.defaultId,
      agents: heartbeatAgents,
    },
    channelSummary,
    queuedSystemEvents,
    sessions: {
      paths: Array.from(paths),
      count: totalSessions,
      defaults: {
        model: configModel ?? null,
        contextTokens: configContextTokens ?? null,
      },
      recent,
      byAgent,
    },
  };
}
