import * as z from 'zod';
import { httpClient } from '~~/server/lib/triplit';
import { renamePrompt } from '~~/prompts';
import { schema } from '~~/triplit/schema';
import { type Entity } from '@triplit/client';
import { generateText } from 'ai';
import { GatewayFetchError, getProviderDetails, type ModelGateway } from '~~/server/utils/ai-provider';
import { addPendingRename } from '~~/server/utils/renames';
import { assert } from '~~/utils/assert';

export default defineEventHandler(async (event) => {
    await protectRoute(event);

    const userId = event.context.user!.id;
    const topicId = getRouterParam(event, 'topicId')!;

    const result = await readValidatedBody(event, (body) =>
        z
            .object({
                modelId: z.string(),
                prompt: z.string(),
                providerApiKey: z.string().optional(),
            })
            .safeParse(body),
    );
    if (!result.success) {
        throw createError({
            statusCode: 400,
            message: result.error.issues[0]!.message,
            data: {
                code: 'INVALID_BODY',
                ok: false,
            }
        });
    }

    const { modelId, prompt, providerApiKey } = result.data;

    const model = await httpClient.fetchOne(httpClient.query('models').Where('id', '=', modelId).Include('provider'));
    if (model === null || model.providerId !== model.providerId || model.userId !== userId || model.provider === null) {
        throw createError({
            statusCode: 400,
            statusMessage: 'Invalid model',
            data: {
                code: 'INVALID_MODEL',
                ok: false,
            }
        });
    }

    const providerDetails = await getProviderDetails(model.provider, providerApiKey, model);
    if (!providerDetails.ok) {
        switch (providerDetails.error) {
            case GatewayFetchError.NoProviderApiKey: {
                setResponseStatus(event, 400, "No provider API key");
                throw createError({
                    statusCode: 400,
                    statusMessage: `${model.provider.type} provider requires an API key`,
                    data: {
                        code: 'NO_PROVIDER_API_KEY',
                        ok: false,
                    }
                });
            }
            case GatewayFetchError.NoProviderBaseUrl: {
                throw createError({
                    statusCode: 400,
                    statusMessage: 'Invalid provider URL',
                    data: {
                        code: 'BAD_PROVIDER_URL',
                        ok: false,
                    }
                });
            }
        }
    }

    const { gateway } = providerDetails.data;
    if (gateway === null) {
        throw createError({
            statusCode: 500,
            statusMessage: 'Invalid gateway',
            data: {
                code: 'INVALID_GATEWAY',
                ok: false,
            }
        });
    }

    const [renameId, pendingRename] = addPendingRename(topicId);
    event.waitUntil(autoRename(topicId, renameId, pendingRename.abortController, { gateway: gateway.gateway, model }, gateway.textTransformer, prompt));

    return {
        renameId,
        ok: true,
    };
});

const autoRename = async (
    topicId: string,
    renameId: string,
    abortController: AbortController,
    model: {
        gateway: ModelGateway,
        model: Entity<typeof schema, 'models'>,
    },
    textTransformer: ((text: string) => string) | ((text: string) => string)[] | undefined,
    prompt: string,
) => {
    try {
        const response = await generateText({
            model: model.gateway(model.model.externalId),
            system: renamePrompt,
            prompt,
            timeout: 90 * 1000,
            abortSignal: abortController.signal,
        })

        let text = response.text;

        if (textTransformer !== undefined) {
            if (Array.isArray(textTransformer)) {
                for (const transformer of textTransformer) {
                    text = transformer(text);
                }
            } else {
                text = textTransformer(text);
            }
        }

        await httpClient.update('topics', topicId, {
            name: text,
        });
    } catch (error) {
        console.error('Failed to auto-rename:', error);
    } finally {
        completeRename(renameId);
        await httpClient.update('topics', topicId, {
            renaming: false
        });
    }
}