import { LanguageModelV1 } from "ai";
import { createOpenAI } from "@ai-sdk/openai";
import { createGoogleGenerativeAI as createGoogle } from "@ai-sdk/google";
import { createAnthropic } from "@ai-sdk/anthropic";
import { createOpenRouter } from "@openrouter/ai-sdk-provider";
import { createOllama } from "ollama-ai-provider";
import { createOpenAICompatible } from "@ai-sdk/openai-compatible";
import type { LargeLanguageModel, UserSettings } from "../../lib/schemas";
import { getEnvVar } from "./read_env";
import log from "electron-log";
import { getLanguageModelProviders } from "../shared/language_model_helpers";
import { LanguageModelProvider } from "../ipc_types";
import { llmErrorStore } from "@/main/llm_error_store";
import { createDyadEngine } from "./llm_engine_provider";
import { findLanguageModel } from "./findLanguageModel";
import { LM_STUDIO_BASE_URL } from "./lm_studio_utils";

const dyadLocalEngine = process.env.DYAD_LOCAL_ENGINE;
const dyadGatewayUrl = process.env.DYAD_GATEWAY_URL;

const AUTO_MODELS = [
  {
    provider: "google",
    name: "gemini-2.5-flash-preview-05-20",
  },
  {
    provider: "anthropic",
    name: "claude-3-7-sonnet-latest",
  },
  {
    provider: "openai",
    name: "gpt-4.1",
  },
];

export interface ModelClient {
  model: LanguageModelV1;
  builtinProviderId?: string;
}

interface File {
  path: string;
  content: string;
}

const logger = log.scope("getModelClient");
export async function getModelClient(
  model: LargeLanguageModel,
  settings: UserSettings,
  files?: File[],
): Promise<{
  modelClient: ModelClient;
  backupModelClients: ModelClient[];
  isEngineEnabled?: boolean;
}> {
  const allProviders = await getLanguageModelProviders();

  const dyadApiKey = settings.providerSettings?.auto?.apiKey?.value;
  // Handle 'auto' provider by trying each model in AUTO_MODELS until one works
  if (model.provider === "auto") {
    for (const autoModel of AUTO_MODELS) {
      const providerInfo = allProviders.find(
        (p) => p.id === autoModel.provider,
      );
      const envVarName = providerInfo?.envVarName;

      const apiKey =
        dyadApiKey ||
        settings.providerSettings?.[autoModel.provider]?.apiKey?.value ||
        (envVarName ? getEnvVar(envVarName) : undefined);

      if (apiKey) {
        logger.log(
          `Using provider: ${autoModel.provider} model: ${autoModel.name}`,
        );
        // Recursively call with the specific model found
        return await getModelClient(
          {
            provider: autoModel.provider,
            name: autoModel.name,
          },
          settings,
          files,
        );
      }
    }
    // If no models have API keys, throw an error
    throw new Error(
      "No API keys available for any model supported by the 'auto' provider.",
    );
  }

  // --- Handle specific provider ---
  const providerConfig = allProviders.find((p) => p.id === model.provider);

  if (!providerConfig) {
    throw new Error(`Configuration not found for provider: ${model.provider}`);
  }

  // Handle Dyad Pro override
  if (dyadApiKey && settings.enableDyadPro) {
    // Check if the selected provider supports Dyad Pro (has a gateway prefix) OR
    // we're using local engine.
    // IMPORTANT: some providers like OpenAI have an empty string gateway prefix,
    // so we do a nullish and not a truthy check here.
    if (providerConfig.gatewayPrefix != null || dyadLocalEngine) {
      const languageModel = await findLanguageModel(model);
      const engineProMode =
        settings.enableProSmartFilesContextMode ||
        settings.enableProLazyEditsMode;
      // Currently engine is only used for turbo edits.
      const isEngineEnabled = Boolean(
        engineProMode &&
          languageModel?.type === "cloud" &&
          languageModel?.supportsTurboEdits,
      );
      const provider = isEngineEnabled
        ? createDyadEngine({
            apiKey: dyadApiKey,
            baseURL: dyadLocalEngine ?? "https://engine.dyad.sh/v1",
            dyadOptions: {
              enableLazyEdits: settings.enableProLazyEditsMode,
              enableSmartFilesContext: settings.enableProSmartFilesContextMode,
            },
          })
        : createOpenAICompatible({
            name: "dyad-gateway",
            apiKey: dyadApiKey,
            baseURL: dyadGatewayUrl ?? "https://llm-gateway.dyad.sh/v1",
          });

      logger.info(`Using Dyad Pro API key. engine_enabled=${isEngineEnabled}`);
      // Do not use free variant (for openrouter).
      const modelName = model.name.split(":free")[0];
      const autoModelClient = {
        model: provider(
          `${providerConfig.gatewayPrefix || ""}${modelName}`,
          engineProMode
            ? {
                files,
              }
            : undefined,
        ),
        builtinProviderId: "auto",
      };
      const googleSettings = settings.providerSettings?.google;

      // Budget saver mode logic (all must be true):
      // 1. Pro Saver Mode is enabled
      // 2. Provider is Google
      // 3. API Key is set
      // 4. Has no recent errors
      if (
        settings.enableProSaverMode &&
        providerConfig.id === "google" &&
        googleSettings &&
        googleSettings.apiKey?.value &&
        llmErrorStore.modelHasNoRecentError({
          model: model.name,
          provider: providerConfig.id,
        })
      ) {
        return {
          modelClient: getRegularModelClient(
            {
              provider: providerConfig.id,
              name: model.name,
            },
            settings,
            providerConfig,
          ).modelClient,
          backupModelClients: [autoModelClient],
          isEngineEnabled,
        };
      } else {
        return {
          modelClient: autoModelClient,
          backupModelClients: [],
          isEngineEnabled,
        };
      }
    } else {
      logger.warn(
        `Dyad Pro enabled, but provider ${model.provider} does not have a gateway prefix defined. Falling back to direct provider connection.`,
      );
      // Fall through to regular provider logic if gateway prefix is missing
    }
  }
  return getRegularModelClient(model, settings, providerConfig);
}

function getRegularModelClient(
  model: LargeLanguageModel,
  settings: UserSettings,
  providerConfig: LanguageModelProvider,
) {
  // Get API key for the specific provider
  const apiKey =
    settings.providerSettings?.[model.provider]?.apiKey?.value ||
    (providerConfig.envVarName
      ? getEnvVar(providerConfig.envVarName)
      : undefined);

  const providerId = providerConfig.id;
  // Create client based on provider ID or type
  switch (providerId) {
    case "openai": {
      const provider = createOpenAI({ apiKey });
      return {
        modelClient: {
          model: provider(model.name),
          builtinProviderId: providerId,
        },
        backupModelClients: [],
      };
    }
    case "anthropic": {
      const provider = createAnthropic({ apiKey });
      return {
        modelClient: {
          model: provider(model.name),
          builtinProviderId: providerId,
        },
        backupModelClients: [],
      };
    }
    case "google": {
      const provider = createGoogle({ apiKey });
      return {
        modelClient: {
          model: provider(model.name),
          builtinProviderId: providerId,
        },
        backupModelClients: [],
      };
    }
    case "openrouter": {
      const provider = createOpenRouter({ apiKey });
      return {
        modelClient: {
          model: provider(model.name),
          builtinProviderId: providerId,
        },
        backupModelClients: [],
      };
    }
    case "ollama": {
      // Ollama typically runs locally and doesn't require an API key in the same way
      const provider = createOllama({
        baseURL: process.env.OLLAMA_HOST,
      });
      return {
        modelClient: {
          model: provider(model.name),
        },
        backupModelClients: [],
      };
    }
    case "lmstudio": {
      // LM Studio uses OpenAI compatible API
      const baseURL = providerConfig.apiBaseUrl || LM_STUDIO_BASE_URL + "/v1";
      const provider = createOpenAICompatible({
        name: "lmstudio",
        baseURL,
      });
      return {
        modelClient: {
          model: provider(model.name),
        },
        backupModelClients: [],
      };
    }
    default: {
      // Handle custom providers
      if (providerConfig.type === "custom") {
        if (!providerConfig.apiBaseUrl) {
          throw new Error(
            `Custom provider ${model.provider} is missing the API Base URL.`,
          );
        }
        // Assume custom providers are OpenAI compatible for now
        const provider = createOpenAICompatible({
          name: providerConfig.id,
          baseURL: providerConfig.apiBaseUrl,
          apiKey,
        });
        return {
          modelClient: {
            model: provider(model.name),
          },
          backupModelClients: [],
        };
      }
      // If it's not a known ID and not type 'custom', it's unsupported
      throw new Error(`Unsupported model provider: ${model.provider}`);
    }
  }
}
