import * as z from 'zod';
import { renamePrompt } from '~~/prompts';
import { generateText } from 'ai';
import { GatewayFetchError, getProviderDetails, type ModelGateway } from '~~/server/utils/ai-provider';
import { addPendingRename } from '~~/server/utils/renames';
import { userEvents } from '~~/server/utils/events';
import { db } from '~~/server/lib/db';
import { type Model } from '~/composables/useModels';
import { topics } from '~~/drizzle/schema';
import { eq } from 'drizzle-orm';

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(),
                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 firstMessage = await db.query.messages.findFirst({
        where: {
            topicId,
            userId,
        },
        orderBy: {
            createdAt: 'asc',
        },
        with: {
            parts: true,
        },
    });

    if (firstMessage === undefined) {
        throw createError({
            statusCode: 400,
            statusMessage: 'Invalid topic',
            data: {
                code: 'INVALID_TOPIC',
                ok: false,
            }
        });
    }

    if (firstMessage.role !== 'user') {
        throw createError({
            statusCode: 400,
            statusMessage: 'Unimplemented',
            data: {
                code: 'INVALID_TOPIC',
                ok: false,
            }
        });
    }

    const { modelId, providerApiKey } = result.data;

    const topic = await db.query.topics.findFirst({
        where: {
            id: topicId,
            userId,
        },
    });

    if (topic === undefined || topic.userId !== userId) {
        throw createError({
            statusCode: 400,
            statusMessage: 'Invalid topic',
            data: {
                code: 'INVALID_TOPIC',
                ok: false,
            }
        });
    }

    if (topic.renaming) {
        throw createError({
            statusCode: 400,
            statusMessage: 'Already renaming',
            data: {
                code: 'ALREADY_RENAMING',
                ok: false,
            }
        });
    }

    const model = await db.query.models.findFirst({
        where: {
            id: modelId,
            userId,
        },
        with: {
            provider: true,
        },
    });

    if (model === undefined || model.userId !== userId) {
        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 abortController = addPendingRename(topicId);
    event.waitUntil(autoRename(topicId, abortController, { gateway: gateway.gateway, model }, gateway.textTransformer, firstMessage.content!, userId));

    return {
        ok: true,
    };
});

const autoRename = async (
    topicId: string,
    abortController: AbortController,
    model: {
        gateway: ModelGateway,
        model: Model,
    },
    textTransformer: ((text: string) => string) | ((text: string) => string)[] | undefined,
    prompt: string,
    userId: string,
) => {
    try {
        await db.update(topics).set({
            renaming: true,
        }).where(eq(topics.id, topicId));
        userEvents.emit(model.model.userId, 'topics', {
            op: 'update',
            payload: {
                topicId,
                renaming: true,
            },
        });

        const response = await generateText({
            model: model.gateway(model.model.externalId),
            providerOptions: {
                openrouter: {
                    user: userId,
                }
            },
            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 db.update(topics).set({
            renaming: false,
            name: text,
        }).where(eq(topics.id, topicId));
        userEvents.emit(model.model.userId, 'topics', {
            op: 'update',
            payload: {
                topicId,
                name: text,
                renaming: false,
            },
        });
        topicEvents.emit(topicId, {
            type: 'topic_updated',
            payload: {
                topicId,
                name: text,
                renaming: false,
            },
        });
    } catch (error) {
        console.error('Failed to auto-rename:', error);
        await db.update(topics).set({
            renaming: false,
        }).where(eq(topics.id, topicId));
        userEvents.emit(model.model.userId, 'topics', {
            op: 'update',
            payload: {
                topicId,
                renaming: false,
            },
        });
        topicEvents.emit(topicId, {
            type: 'topic_updated',
            payload: {
                topicId,
                renaming: false,
            },
        });
    } finally {
        completeRename(topicId);
    }
}