import { Injectable, Optional } from '@nestjs/common';

import { Models } from '../../../models';
import type { AiActionRunStatus } from '../../../models/copilot-action-run';
import {
  type NativeActionEvent,
  type NativeActionRuntimeInput,
  runNativeActionRecipePreparedStream,
} from '../../../native';
import type {
  CopilotImageOptions,
  CopilotProviderType,
  CopilotStructuredOptions,
  PromptMessage,
} from '../providers/types';
import type { ChatSession } from '../session';
import {
  projectActionResultToAssistantTurn,
  summarizeActionResult,
} from './action-output-projector';
import {
  buildStructuredResponseFromSchemaJson,
  type RequiredStructuredOutputContract,
} from './contracts';
import { ExecutionPlanBuilder } from './execution-plan';
import { TurnPersistence } from './hosts/turn-persistence';

type ActionRuntimeBridgeNativeInput = Omit<
  NativeActionRuntimeInput,
  'recipeId' | 'recipeVersion'
>;

export type ActionRuntimeBridgeInput = {
  userId: string;
  workspaceId: string;
  docId?: string | null;
  session?: ChatSession;
  userMessageId?: string | null;
  compatSubmissionId?: string | null;
  actionId: string;
  actionVersion: string;
  attempt?: number;
  retryOf?: string | null;
  inputSnapshot?: unknown;
  nativeInput?: ActionRuntimeBridgeNativeInput;
  onRunCreated?: (
    context: ActionRuntimeBridgeRunContext
  ) => Promise<void> | void;
  prepareStructuredRoutes?: {
    stepId?: string;
    modelId?: string;
    messages: PromptMessage[];
    options?: CopilotStructuredOptions;
    prefer?: CopilotProviderType;
    responseSchemaJson?: Record<string, unknown>;
    responseContract?: RequiredStructuredOutputContract;
  };
  prepareImageRoutes?: {
    stepId?: string;
    modelId?: string;
    messages: PromptMessage[];
    options?: CopilotImageOptions;
    prefer?: CopilotProviderType;
  };
  persistAttachment?: (attachment: unknown) => Promise<unknown> | unknown;
  signal?: AbortSignal;
};

export type ActionRuntimeBridgeEvent = NativeActionEvent & {
  runId: string;
};

export type ActionRuntimeBridgeRunContext = {
  runId: string;
  attempt: number;
};

function extractResultArtifacts(result: unknown) {
  if (!result || typeof result !== 'object') {
    return [];
  }
  const value = result as { artifacts?: unknown; attachments?: unknown };
  if (Array.isArray(value.artifacts)) {
    return value.artifacts;
  }
  if (Array.isArray(value.attachments)) {
    return value.attachments;
  }
  return [];
}

function resolveFinalStatus(
  event: NativeActionEvent | undefined,
  signal?: AbortSignal
): Extract<AiActionRunStatus, 'succeeded' | 'failed' | 'aborted'> {
  if (signal?.aborted || event?.status === 'aborted') {
    return 'aborted';
  }
  if (event?.type === 'action_done' && event.status === 'succeeded') {
    return 'succeeded';
  }
  return 'failed';
}

@Injectable()
export class ActionRuntimeBridge {
  constructor(
    private readonly models: Models,
    private readonly turnPersistence: TurnPersistence,
    @Optional() private readonly plans?: ExecutionPlanBuilder
  ) {}

  protected runNativeStream(
    input: NativeActionRuntimeInput,
    signal?: AbortSignal
  ) {
    return runNativeActionRecipePreparedStream(input, signal);
  }

  private async prepareNativeInput(
    input: ActionRuntimeBridgeInput
  ): Promise<ActionRuntimeBridgeNativeInput & { input: unknown }> {
    const nativeInput = {
      ...input.nativeInput,
      input: input.nativeInput?.input ?? {},
    };
    const structured = input.prepareStructuredRoutes;
    const image = input.prepareImageRoutes;
    if (!structured && !image) {
      return nativeInput;
    }
    if (!this.plans) {
      throw new Error('Action route preparation is not available');
    }
    const state =
      nativeInput.input && typeof nativeInput.input === 'object'
        ? { ...(nativeInput.input as Record<string, unknown>) }
        : {};

    if (structured) {
      const responseContract =
        structured.responseContract ??
        (buildStructuredResponseFromSchemaJson(
          structured.responseSchemaJson ?? { type: 'object' }
        ) as RequiredStructuredOutputContract);
      const plan = await this.plans.buildStructuredPlan(
        { modelId: structured.modelId },
        structured.messages,
        structured.options,
        structured.prefer ? { prefer: structured.prefer } : undefined,
        responseContract
      );
      const preparedRoutes = plan.nativeDispatch?.structured?.routes;
      if (!preparedRoutes?.length) {
        throw new Error('No native structured provider route prepared');
      }

      const existingPreparedRoutes =
        state.preparedRoutes &&
        typeof state.preparedRoutes === 'object' &&
        !Array.isArray(state.preparedRoutes)
          ? (state.preparedRoutes as Record<string, unknown>)
          : {};
      state.preparedRoutes = {
        ...existingPreparedRoutes,
        [structured.stepId ?? 'generate']: preparedRoutes,
      };
    }

    if (image) {
      const plan = await this.plans.buildImagePlan(
        { modelId: image.modelId },
        image.messages,
        image.options,
        image.prefer ? { prefer: image.prefer } : undefined
      );
      const preparedRoutes = plan.nativeDispatch?.image?.routes;
      if (!preparedRoutes?.length) {
        throw new Error('No native image provider route prepared');
      }

      const existingPreparedRoutes =
        state.preparedRoutes &&
        typeof state.preparedRoutes === 'object' &&
        !Array.isArray(state.preparedRoutes)
          ? (state.preparedRoutes as Record<string, unknown>)
          : {};
      state.preparedRoutes = {
        ...existingPreparedRoutes,
        [image.stepId ?? 'generate-image']: preparedRoutes,
      };
    }

    return {
      ...nativeInput,
      input: state,
    };
  }

  private async projectAssistantResult(
    input: ActionRuntimeBridgeInput,
    result: unknown,
    artifacts: unknown[],
    wasAborted: boolean
  ) {
    if (!input.session) return null;
    const turn = projectActionResultToAssistantTurn({
      session: input.session,
      actionId: input.actionId,
      result,
      artifacts,
      wasAborted,
    });
    if (!turn) return null;
    return await this.turnPersistence.persistProjectedResult(
      input.session,
      turn,
      wasAborted
    );
  }

  private async resolveAttempt(input: ActionRuntimeBridgeInput) {
    if (!input.retryOf) {
      return input.attempt ?? 1;
    }

    const previous = await this.models.copilotActionRun.get(input.retryOf);
    if (!previous) {
      throw new Error('Retry source action run not found');
    }
    if (
      previous.userId !== input.userId ||
      previous.workspaceId !== input.workspaceId ||
      previous.actionId !== input.actionId ||
      previous.actionVersion !== input.actionVersion ||
      previous.sessionId !== (input.session?.config.sessionId ?? null)
    ) {
      throw new Error('Retry source action run does not match current action');
    }
    if (input.attempt && input.attempt <= previous.attempt) {
      throw new Error('Retry attempt must be greater than source action run');
    }
    if (input.attempt) {
      return input.attempt;
    }
    return (previous?.attempt ?? 1) + 1;
  }

  async *runStream(
    input: ActionRuntimeBridgeInput
  ): AsyncIterableIterator<ActionRuntimeBridgeEvent> {
    const attempt = await this.resolveAttempt(input);
    const run = await this.models.copilotActionRun.create({
      userId: input.userId,
      workspaceId: input.workspaceId,
      docId: input.docId,
      sessionId: input.session?.config.sessionId,
      userMessageId: input.userMessageId,
      compatSubmissionId: input.compatSubmissionId,
      actionId: input.actionId,
      actionVersion: input.actionVersion,
      attempt,
      retryOf: input.retryOf,
      inputSnapshot: input.inputSnapshot,
    });
    await this.models.copilotActionRun.markRunning(run.id);
    await input.onRunCreated?.({
      runId: run.id,
      attempt,
    });

    let finalEvent: NativeActionEvent | undefined;
    const attachments: unknown[] = [];
    try {
      const nativeInput = await this.prepareNativeInput({
        ...input,
      });
      for await (const event of this.runNativeStream(
        {
          ...nativeInput,
          recipeId: input.actionId,
          recipeVersion: input.actionVersion,
        },
        input.signal
      )) {
        finalEvent = event;
        let projectedEvent = event;
        if (event.type === 'attachment') {
          const attachment = input.persistAttachment
            ? await input.persistAttachment(event.attachment)
            : event.attachment;
          attachments.push(attachment);
          projectedEvent = { ...event, attachment };
        }
        yield { ...projectedEvent, runId: run.id };
      }
    } catch (error) {
      finalEvent = {
        type: 'error',
        actionId: input.actionId,
        actionVersion: input.actionVersion,
        status: input.signal?.aborted ? 'aborted' : 'failed',
        errorCode: input.signal?.aborted
          ? 'action_aborted'
          : 'action_bridge_stream_error',
        errorMessage:
          error instanceof Error ? error.message : 'action stream failed',
      };
      yield { ...finalEvent, runId: run.id };
    } finally {
      let status = resolveFinalStatus(finalEvent, input.signal);
      const result = finalEvent?.result;
      const artifacts =
        status === 'succeeded'
          ? [...attachments, ...extractResultArtifacts(result)]
          : undefined;
      let assistantMessageId: string | null = null;
      let errorCode = status === 'succeeded' ? null : finalEvent?.errorCode;
      if (status === 'succeeded' || status === 'aborted') {
        try {
          assistantMessageId =
            (await this.projectAssistantResult(
              input,
              result,
              artifacts ?? [],
              status === 'aborted'
            )) ?? null;
        } catch {
          status = 'failed';
          errorCode = 'action_output_projection_failed';
        }
      }

      await this.models.copilotActionRun.complete(run.id, {
        status,
        result: status === 'succeeded' ? result : undefined,
        artifacts: status === 'succeeded' ? artifacts : undefined,
        resultSummary:
          status === 'succeeded' ? summarizeActionResult(result) : null,
        errorCode,
        trace: finalEvent?.trace ?? undefined,
        assistantMessageId,
      });
    }
  }
}