import { classifyGatewayStaleInstall } from "../../gateway/stale-install.js";
import { emitAgentEvent } from "../../infra/agent-events.js";
import { formatErrorMessageForDisplay } from "../../infra/error-diagnostics.js";
import { formatErrorMessage } from "../../infra/errors.js";
import { createSubsystemLogger } from "../../logging/subsystem.js";
import { normalizeAgentRunTerminalDeliverySnapshot } from "../agent-run-terminal-delivery.js";
import type { AgentRunTerminalOutcome } from "../agent-run-terminal-outcome.js";
import { normalizeAgentRunTerminalReceipt } from "../agent-run-terminal-receipt.js";
import type { EmbeddedAgentRunEntryTerminal } from "../embedded-agent-runner/run-entry.js";
import { getFailoverErrorCode } from "../failover/error.js";
import { renderFailoverCodeUserCopy } from "../failover/user-copy.js";
import {
  AGENT_RUN_SUPERSEDED_STOP_REASON,
  resolveAgentRunAbortLifecycleFields,
  resolveAgentRunErrorLifecycleFields,
} from "../run-termination.js";
import type { AgentAttemptLifecycleState } from "./attempt-callbacks.js";
import type { AgentAttemptResult } from "./runtime-loaders.js";

const log = createSubsystemLogger("agents/agent-command");

const formatLifecycleError = (error: unknown): string => {
  const staleInstall = classifyGatewayStaleInstall(error);
  return staleInstall
    ? staleInstall.error.message
    : formatErrorMessageForDisplay(error, renderFailoverCodeUserCopy(getFailoverErrorCode(error)));
};

function resolveTerminalLogLevel(
  outcome: AgentRunTerminalOutcome,
): "info" | "warn" | "error" | undefined {
  if (!outcome.stopReason || outcome.stopReason === "end_turn") {
    return undefined;
  }
  if (outcome.reason === "completed") {
    return "info";
  }
  return outcome.status === "timeout" ? "warn" : "error";
}

export function applyAgentRunAbortMetadata<T extends { meta: object }>(
  result: T,
  signal: AbortSignal | undefined,
): T {
  const abortFields = resolveAgentRunAbortLifecycleFields(signal);
  if (abortFields.aborted !== true) {
    return result;
  }
  return {
    ...result,
    meta: {
      ...result.meta,
      ...abortFields,
    },
  };
}

export function createAgentCommandLifecycle(params: {
  runId: string;
  lifecycleGeneration: () => string;
  startedAt: number;
  abortSignal?: AbortSignal;
  state: AgentAttemptLifecycleState;
}) {
  let lifecycleFinishingEmitted = false;
  const resolveResultError = (runResult: AgentAttemptResult, includeErrorPayload: boolean) =>
    params.state.lifecycleError ??
    (includeErrorPayload
      ? runResult.payloads?.find(
          (payload) => payload.isError === true && typeof payload.text === "string",
        )?.text
      : undefined) ??
    (runResult.meta.error ? runResult.meta.error.message.trim() || "Agent run failed" : undefined);
  const resolveTerminalError = (
    runResult: AgentAttemptResult,
    fallbackExhausted: boolean,
    terminal: EmbeddedAgentRunEntryTerminal,
  ) =>
    params.state.lifecycleError ??
    (terminal.outcome.status === "timeout"
      ? terminal.outcome.error
      : resolveResultError(runResult, fallbackExhausted)) ??
    (fallbackExhausted ? "All model fallback candidates failed" : "Agent run failed");
  const emitTerminalPhase = (
    phase: "finishing" | "end" | "error",
    terminal: EmbeddedAgentRunEntryTerminal,
    error = terminal.outcome.status === "timeout" ? terminal.outcome.error : undefined,
  ) => {
    const { aborted, yielded, replayInvalid, terminalReply } = terminal.metadata;
    const terminalDelivery = normalizeAgentRunTerminalDeliverySnapshot(
      terminal.metadata.terminalDelivery,
    );
    const terminalReceipt = normalizeAgentRunTerminalReceipt(terminal.metadata.terminalReceipt);
    const { stopReason, livenessState, timeoutPhase, providerStarted } = terminal.outcome;
    const abortFields = resolveAgentRunAbortLifecycleFields(params.abortSignal);
    emitAgentEvent({
      runId: params.runId,
      lifecycleGeneration: params.lifecycleGeneration(),
      stream: "lifecycle",
      data: {
        phase,
        startedAt: params.startedAt,
        endedAt: Date.now(),
        aborted: typeof aborted === "boolean" ? aborted : false,
        stopReason,
        ...(yielded === true ? { yielded } : {}),
        ...(replayInvalid === true ? { replayInvalid } : {}),
        ...(livenessState ? { livenessState } : {}),
        ...(timeoutPhase ? { timeoutPhase } : {}),
        ...(providerStarted !== undefined ? { providerStarted } : {}),
        ...(error ? { error: formatErrorMessage(error) } : {}),
        ...(error && params.state.lifecycleErrorObservation
          ? { errorObservation: params.state.lifecycleErrorObservation }
          : {}),
        // Finishing is an attempt fence, not the outer execution's final publication.
        ...(phase !== "finishing" ? { executionSettled: true } : {}),
        ...(terminalDelivery ? { terminalDelivery } : {}),
        ...(terminalReceipt ? { terminalReceipt } : {}),
        ...(terminalReply ? { terminalReply } : {}),
        ...(stopReason === AGENT_RUN_SUPERSEDED_STOP_REASON
          ? { aborted: true, stopReason }
          : abortFields),
      },
    });
  };

  return {
    emitBasicError(error: unknown, extraData?: Record<string, unknown>) {
      if (params.state.lifecycleEnded) {
        return;
      }
      params.state.lifecycleEnded = true;
      emitAgentEvent({
        runId: params.runId,
        lifecycleGeneration: params.lifecycleGeneration(),
        stream: "lifecycle",
        data: {
          phase: "error",
          startedAt: params.startedAt,
          endedAt: Date.now(),
          error: formatLifecycleError(error),
          ...(params.state.lifecycleErrorObservation
            ? { errorObservation: params.state.lifecycleErrorObservation }
            : {}),
          ...extraData,
          executionSettled: true,
        },
      });
    },
    emitFinishing(terminal: EmbeddedAgentRunEntryTerminal) {
      if (
        params.state.lifecycleEnded ||
        params.state.lifecycleFinishing ||
        lifecycleFinishingEmitted
      ) {
        return;
      }
      lifecycleFinishingEmitted = true;
      params.state.lifecycleFinishing = true;
      emitTerminalPhase("finishing", terminal);
    },
    emitEnd(terminal: EmbeddedAgentRunEntryTerminal) {
      if (params.state.lifecycleEnded) {
        return;
      }
      params.state.lifecycleEnded = true;
      const stopReason = terminal.outcome.stopReason;
      const logLevel = resolveTerminalLogLevel(terminal.outcome);
      if (logLevel) {
        log[logLevel](`[agent] run ${params.runId} ended with stopReason=${stopReason}`);
      }
      emitTerminalPhase("end", terminal);
    },
    resolveResultError,
    resolveTerminalError,
    emitResultError(
      runResult: AgentAttemptResult,
      fallbackExhausted: boolean,
      terminal: EmbeddedAgentRunEntryTerminal,
    ) {
      if (params.state.lifecycleEnded) {
        return;
      }
      params.state.lifecycleEnded = true;
      const error = resolveTerminalError(runResult, fallbackExhausted, terminal);
      emitTerminalPhase("error", terminal, error);
    },
    emitPostTurnError(error: unknown, terminal: EmbeddedAgentRunEntryTerminal) {
      if (params.state.lifecycleEnded) {
        return;
      }
      params.state.lifecycleEnded = true;
      const terminalDelivery = normalizeAgentRunTerminalDeliverySnapshot(
        terminal.metadata.terminalDelivery,
      );
      emitAgentEvent({
        runId: params.runId,
        lifecycleGeneration: params.lifecycleGeneration(),
        stream: "lifecycle",
        data: {
          phase: "error",
          startedAt: params.startedAt,
          endedAt: Date.now(),
          error: formatLifecycleError(error),
          ...(terminalDelivery ? { terminalDelivery } : {}),
          ...resolveAgentRunErrorLifecycleFields(error, params.abortSignal),
          executionSettled: true,
        },
      });
    },
  };
}