import fs from "node:fs/promises";
import type { ThinkLevel } from "../../auto-reply/thinking.js";
import { enqueueCommandInLane } from "../../process/command-queue.js";
import { resolveUserPath } from "../../utils.js";
import { isMarkdownCapableMessageChannel } from "../../utils/message-channel.js";
import { resolveClawdbotAgentDir } from "../agent-paths.js";
import {
  markAuthProfileFailure,
  markAuthProfileGood,
  markAuthProfileUsed,
} from "../auth-profiles.js";
import {
  CONTEXT_WINDOW_HARD_MIN_TOKENS,
  CONTEXT_WINDOW_WARN_BELOW_TOKENS,
  evaluateContextWindowGuard,
  resolveContextWindowInfo,
} from "../context-window-guard.js";
import { DEFAULT_CONTEXT_TOKENS, DEFAULT_MODEL, DEFAULT_PROVIDER } from "../defaults.js";
import { FailoverError, resolveFailoverStatus } from "../failover-error.js";
import {
  ensureAuthProfileStore,
  getApiKeyForModel,
  resolveAuthProfileOrder,
} from "../model-auth.js";
import { ensureClawdbotModelsJson } from "../models-config.js";
import {
  classifyFailoverReason,
  formatAssistantErrorText,
  isAuthAssistantError,
  isCompactionFailureError,
  isContextOverflowError,
  isFailoverAssistantError,
  isFailoverErrorMessage,
  isRateLimitAssistantError,
  isTimeoutErrorMessage,
  pickFallbackThinkingLevel,
} from "../pi-embedded-helpers.js";
import { normalizeUsage, type UsageLike } from "../usage.js";

import { resolveGlobalLane, resolveSessionLane } from "./lanes.js";
import { log } from "./logger.js";
import { resolveModel } from "./model.js";
import { runEmbeddedAttempt } from "./run/attempt.js";
import type { RunEmbeddedPiAgentParams } from "./run/params.js";
import { buildEmbeddedRunPayloads } from "./run/payloads.js";
import type { EmbeddedPiAgentMeta, EmbeddedPiRunResult } from "./types.js";
import { describeUnknownError } from "./utils.js";

type ApiKeyInfo = {
  apiKey: string;
  profileId?: string;
  source: string;
};

export async function runEmbeddedPiAgent(
  params: RunEmbeddedPiAgentParams,
): Promise<EmbeddedPiRunResult> {
  const sessionLane = resolveSessionLane(params.sessionKey?.trim() || params.sessionId);
  const globalLane = resolveGlobalLane(params.lane);
  const enqueueGlobal =
    params.enqueue ?? ((task, opts) => enqueueCommandInLane(globalLane, task, opts));
  const channelHint = params.messageChannel ?? params.messageProvider;
  const resolvedToolResultFormat =
    params.toolResultFormat ??
    (channelHint
      ? isMarkdownCapableMessageChannel(channelHint)
        ? "markdown"
        : "plain"
      : "markdown");

  return enqueueCommandInLane(sessionLane, () =>
    enqueueGlobal(async () => {
      const started = Date.now();
      const resolvedWorkspace = resolveUserPath(params.workspaceDir);
      const prevCwd = process.cwd();

      const provider = (params.provider ?? DEFAULT_PROVIDER).trim() || DEFAULT_PROVIDER;
      const modelId = (params.model ?? DEFAULT_MODEL).trim() || DEFAULT_MODEL;
      const agentDir = params.agentDir ?? resolveClawdbotAgentDir();
      await ensureClawdbotModelsJson(params.config, agentDir);

      const { model, error, authStorage, modelRegistry } = resolveModel(
        provider,
        modelId,
        agentDir,
        params.config,
      );
      if (!model) {
        throw new Error(error ?? `Unknown model: ${provider}/${modelId}`);
      }

      const ctxInfo = resolveContextWindowInfo({
        cfg: params.config,
        provider,
        modelId,
        modelContextWindow: model.contextWindow,
        defaultTokens: DEFAULT_CONTEXT_TOKENS,
      });
      const ctxGuard = evaluateContextWindowGuard({
        info: ctxInfo,
        warnBelowTokens: CONTEXT_WINDOW_WARN_BELOW_TOKENS,
        hardMinTokens: CONTEXT_WINDOW_HARD_MIN_TOKENS,
      });
      if (ctxGuard.shouldWarn) {
        log.warn(
          `low context window: ${provider}/${modelId} ctx=${ctxGuard.tokens} (warn<${CONTEXT_WINDOW_WARN_BELOW_TOKENS}) source=${ctxGuard.source}`,
        );
      }
      if (ctxGuard.shouldBlock) {
        log.error(
          `blocked model (context window too small): ${provider}/${modelId} ctx=${ctxGuard.tokens} (min=${CONTEXT_WINDOW_HARD_MIN_TOKENS}) source=${ctxGuard.source}`,
        );
        throw new FailoverError(
          `Model context window too small (${ctxGuard.tokens} tokens). Minimum is ${CONTEXT_WINDOW_HARD_MIN_TOKENS}.`,
          { reason: "unknown", provider, model: modelId },
        );
      }

      const authStore = ensureAuthProfileStore(agentDir, { allowKeychainPrompt: false });
      const explicitProfileId = params.authProfileId?.trim();
      const profileOrder = resolveAuthProfileOrder({
        cfg: params.config,
        store: authStore,
        provider,
        preferredProfile: explicitProfileId,
      });
      if (explicitProfileId && !profileOrder.includes(explicitProfileId)) {
        throw new Error(`Auth profile "${explicitProfileId}" is not configured for ${provider}.`);
      }
      const profileCandidates = profileOrder.length > 0 ? profileOrder : [undefined];
      let profileIndex = 0;

      const initialThinkLevel = params.thinkLevel ?? "off";
      let thinkLevel = initialThinkLevel;
      const attemptedThinking = new Set<ThinkLevel>();
      let apiKeyInfo: ApiKeyInfo | null = null;
      let lastProfileId: string | undefined;

      const resolveApiKeyForCandidate = async (candidate?: string) => {
        return getApiKeyForModel({
          model,
          cfg: params.config,
          profileId: candidate,
          store: authStore,
          agentDir,
        });
      };

      const applyApiKeyInfo = async (candidate?: string): Promise<void> => {
        apiKeyInfo = await resolveApiKeyForCandidate(candidate);
        if (model.provider === "github-copilot") {
          const { resolveCopilotApiToken } =
            await import("../../providers/github-copilot-token.js");
          const copilotToken = await resolveCopilotApiToken({
            githubToken: apiKeyInfo.apiKey,
          });
          authStorage.setRuntimeApiKey(model.provider, copilotToken.token);
        } else {
          authStorage.setRuntimeApiKey(model.provider, apiKeyInfo.apiKey);
        }
        lastProfileId = apiKeyInfo.profileId;
      };

      const advanceAuthProfile = async (): Promise<boolean> => {
        let nextIndex = profileIndex + 1;
        while (nextIndex < profileCandidates.length) {
          const candidate = profileCandidates[nextIndex];
          try {
            await applyApiKeyInfo(candidate);
            profileIndex = nextIndex;
            thinkLevel = initialThinkLevel;
            attemptedThinking.clear();
            return true;
          } catch (err) {
            if (candidate && candidate === explicitProfileId) throw err;
            nextIndex += 1;
          }
        }
        return false;
      };

      try {
        await applyApiKeyInfo(profileCandidates[profileIndex]);
      } catch (err) {
        if (profileCandidates[profileIndex] === explicitProfileId) throw err;
        const advanced = await advanceAuthProfile();
        if (!advanced) throw err;
      }

      try {
        while (true) {
          attemptedThinking.add(thinkLevel);
          await fs.mkdir(resolvedWorkspace, { recursive: true });

          const attempt = await runEmbeddedAttempt({
            sessionId: params.sessionId,
            sessionKey: params.sessionKey,
            messageChannel: params.messageChannel,
            messageProvider: params.messageProvider,
            agentAccountId: params.agentAccountId,
            currentChannelId: params.currentChannelId,
            currentThreadTs: params.currentThreadTs,
            replyToMode: params.replyToMode,
            hasRepliedRef: params.hasRepliedRef,
            sessionFile: params.sessionFile,
            workspaceDir: params.workspaceDir,
            agentDir,
            config: params.config,
            skillsSnapshot: params.skillsSnapshot,
            prompt: params.prompt,
            images: params.images,
            provider,
            modelId,
            model,
            authStorage,
            modelRegistry,
            thinkLevel,
            verboseLevel: params.verboseLevel,
            reasoningLevel: params.reasoningLevel,
            toolResultFormat: resolvedToolResultFormat,
            bashElevated: params.bashElevated,
            timeoutMs: params.timeoutMs,
            runId: params.runId,
            abortSignal: params.abortSignal,
            shouldEmitToolResult: params.shouldEmitToolResult,
            shouldEmitToolOutput: params.shouldEmitToolOutput,
            onPartialReply: params.onPartialReply,
            onAssistantMessageStart: params.onAssistantMessageStart,
            onBlockReply: params.onBlockReply,
            onBlockReplyFlush: params.onBlockReplyFlush,
            blockReplyBreak: params.blockReplyBreak,
            blockReplyChunking: params.blockReplyChunking,
            onReasoningStream: params.onReasoningStream,
            onToolResult: params.onToolResult,
            onAgentEvent: params.onAgentEvent,
            extraSystemPrompt: params.extraSystemPrompt,
            ownerNumbers: params.ownerNumbers,
            enforceFinalTag: params.enforceFinalTag,
          });

          const { aborted, promptError, timedOut, sessionIdUsed, lastAssistant } = attempt;

          if (promptError && !aborted) {
            const errorText = describeUnknownError(promptError);
            if (isContextOverflowError(errorText)) {
              const kind = isCompactionFailureError(errorText)
                ? "compaction_failure"
                : "context_overflow";
              return {
                payloads: [
                  {
                    text:
                      "Context overflow: prompt too large for the model. " +
                      "Try again with less input or a larger-context model.",
                    isError: true,
                  },
                ],
                meta: {
                  durationMs: Date.now() - started,
                  agentMeta: {
                    sessionId: sessionIdUsed,
                    provider,
                    model: model.id,
                  },
                  systemPromptReport: attempt.systemPromptReport,
                  error: { kind, message: errorText },
                },
              };
            }
            // Handle role ordering errors with a user-friendly message
            if (/incorrect role information|roles must alternate/i.test(errorText)) {
              return {
                payloads: [
                  {
                    text:
                      "Message ordering conflict - please try again. " +
                      "If this persists, use /new to start a fresh session.",
                    isError: true,
                  },
                ],
                meta: {
                  durationMs: Date.now() - started,
                  agentMeta: {
                    sessionId: sessionIdUsed,
                    provider,
                    model: model.id,
                  },
                  systemPromptReport: attempt.systemPromptReport,
                  error: { kind: "role_ordering", message: errorText },
                },
              };
            }
            const promptFailoverReason = classifyFailoverReason(errorText);
            if (promptFailoverReason && promptFailoverReason !== "timeout" && lastProfileId) {
              await markAuthProfileFailure({
                store: authStore,
                profileId: lastProfileId,
                reason: promptFailoverReason,
                cfg: params.config,
                agentDir: params.agentDir,
              });
            }
            if (
              isFailoverErrorMessage(errorText) &&
              promptFailoverReason !== "timeout" &&
              (await advanceAuthProfile())
            ) {
              continue;
            }
            const fallbackThinking = pickFallbackThinkingLevel({
              message: errorText,
              attempted: attemptedThinking,
            });
            if (fallbackThinking) {
              log.warn(
                `unsupported thinking level for ${provider}/${modelId}; retrying with ${fallbackThinking}`,
              );
              thinkLevel = fallbackThinking;
              continue;
            }
            // FIX: Throw FailoverError for prompt errors when fallbacks configured
            // This enables model fallback for quota/rate limit errors during prompt submission
            const promptFallbackConfigured =
              (params.config?.agents?.defaults?.model?.fallbacks?.length ?? 0) > 0;
            if (promptFallbackConfigured && isFailoverErrorMessage(errorText)) {
              throw new FailoverError(errorText, {
                reason: promptFailoverReason ?? "unknown",
                provider,
                model: modelId,
                profileId: lastProfileId,
                status: resolveFailoverStatus(promptFailoverReason ?? "unknown"),
              });
            }
            throw promptError;
          }

          const fallbackThinking = pickFallbackThinkingLevel({
            message: lastAssistant?.errorMessage,
            attempted: attemptedThinking,
          });
          if (fallbackThinking && !aborted) {
            log.warn(
              `unsupported thinking level for ${provider}/${modelId}; retrying with ${fallbackThinking}`,
            );
            thinkLevel = fallbackThinking;
            continue;
          }

          const fallbackConfigured =
            (params.config?.agents?.defaults?.model?.fallbacks?.length ?? 0) > 0;
          const authFailure = isAuthAssistantError(lastAssistant);
          const rateLimitFailure = isRateLimitAssistantError(lastAssistant);
          const failoverFailure = isFailoverAssistantError(lastAssistant);
          const assistantFailoverReason = classifyFailoverReason(lastAssistant?.errorMessage ?? "");
          const cloudCodeAssistFormatError = attempt.cloudCodeAssistFormatError;

          // Treat timeout as potential rate limit (Antigravity hangs on rate limit)
          const shouldRotate = (!aborted && failoverFailure) || timedOut;

          if (shouldRotate) {
            if (lastProfileId) {
              const reason =
                timedOut || assistantFailoverReason === "timeout"
                  ? "timeout"
                  : (assistantFailoverReason ?? "unknown");
              await markAuthProfileFailure({
                store: authStore,
                profileId: lastProfileId,
                reason,
                cfg: params.config,
                agentDir: params.agentDir,
              });
              if (timedOut) {
                log.warn(
                  `Profile ${lastProfileId} timed out (possible rate limit). Trying next account...`,
                );
              }
              if (cloudCodeAssistFormatError) {
                log.warn(
                  `Profile ${lastProfileId} hit Cloud Code Assist format error. Tool calls will be sanitized on retry.`,
                );
              }
            }

            const rotated = await advanceAuthProfile();
            if (rotated) continue;

            if (fallbackConfigured) {
              // Prefer formatted error message (user-friendly) over raw errorMessage
              const message =
                (lastAssistant
                  ? formatAssistantErrorText(lastAssistant, {
                      cfg: params.config,
                      sessionKey: params.sessionKey ?? params.sessionId,
                    })
                  : undefined) ||
                lastAssistant?.errorMessage?.trim() ||
                (timedOut
                  ? "LLM request timed out."
                  : rateLimitFailure
                    ? "LLM request rate limited."
                    : authFailure
                      ? "LLM request unauthorized."
                      : "LLM request failed.");
              const status =
                resolveFailoverStatus(assistantFailoverReason ?? "unknown") ??
                (isTimeoutErrorMessage(message) ? 408 : undefined);
              throw new FailoverError(message, {
                reason: assistantFailoverReason ?? "unknown",
                provider,
                model: modelId,
                profileId: lastProfileId,
                status,
              });
            }
          }

          const usage = normalizeUsage(lastAssistant?.usage as UsageLike);
          const agentMeta: EmbeddedPiAgentMeta = {
            sessionId: sessionIdUsed,
            provider: lastAssistant?.provider ?? provider,
            model: lastAssistant?.model ?? model.id,
            usage,
          };

          const payloads = buildEmbeddedRunPayloads({
            assistantTexts: attempt.assistantTexts,
            toolMetas: attempt.toolMetas,
            lastAssistant: attempt.lastAssistant,
            config: params.config,
            sessionKey: params.sessionKey ?? params.sessionId,
            verboseLevel: params.verboseLevel,
            reasoningLevel: params.reasoningLevel,
            toolResultFormat: resolvedToolResultFormat,
            inlineToolResultsAllowed: !params.onPartialReply && !params.onToolResult,
          });

          log.debug(
            `embedded run done: runId=${params.runId} sessionId=${params.sessionId} durationMs=${Date.now() - started} aborted=${aborted}`,
          );
          if (lastProfileId) {
            await markAuthProfileGood({
              store: authStore,
              provider,
              profileId: lastProfileId,
            });
            await markAuthProfileUsed({
              store: authStore,
              profileId: lastProfileId,
            });
          }
          return {
            payloads: payloads.length ? payloads : undefined,
            meta: {
              durationMs: Date.now() - started,
              agentMeta,
              aborted,
              systemPromptReport: attempt.systemPromptReport,
            },
            didSendViaMessagingTool: attempt.didSendViaMessagingTool,
            messagingToolSentTexts: attempt.messagingToolSentTexts,
            messagingToolSentTargets: attempt.messagingToolSentTargets,
          };
        }
      } finally {
        process.chdir(prevCwd);
      }
    }),
  );
}