import { Router } from 'express';
import { z } from 'zod';
import type { Database } from 'sql.js';
import { RecipeService } from '../services/RecipeService.js';
import { SearchIndex } from '../services/SearchIndex.js';
import { asyncHandler } from '../middleware.js';

const createRecipeSchema = z.object({
  title: z.string().min(1, 'Title is required'),
  description: z.string().optional(),
  servings: z.number().int().positive().optional(),
  prep_time_minutes: z.number().int().positive().optional(),
  cook_time_minutes: z.number().int().positive().optional(),
  source_url: z.string().url().optional().or(z.literal('')),
  image_url: z.string().url().optional().or(z.literal('')),
  ingredients: z.array(z.object({
    quantity: z.string().optional(),
    unit: z.string().optional(),
    item: z.string().min(1, 'Ingredient required'),
    notes: z.string().optional(),
  })).min(1, 'At least one ingredient is required'),
  steps: z.array(z.object({
    instruction: z.string().min(1, 'Instruction required'),
  })).min(1, 'At least one step is required'),
  tagIds: z.array(z.number().int().positive()).optional(),
});

const updateRecipeSchema = z.object({
  title: z.string().min(1).optional(),
  description: z.string().optional().nullable(),
  servings: z.number().int().positive().optional().nullable(),
  prep_time_minutes: z.number().int().positive().optional().nullable(),
  cook_time_minutes: z.number().int().positive().optional().nullable(),
  source_url: z.string().url().optional().nullable().or(z.literal('')),
  image_url: z.string().url().optional().nullable().or(z.literal('')),
  ingredients: z.array(z.object({
    quantity: z.string().optional(),
    unit: z.string().optional(),
    item: z.string().min(1).optional(),
    notes: z.string().optional(),
  })).optional(),
  steps: z.array(z.object({ instruction: z.string().min(1).optional() })).optional(),
  tagIds: z.array(z.number().int().positive()).optional(),
});

const recipeFiltersSchema = z.object({
  search: z.string().optional(),
  offset: z.coerce.number().int().nonnegative().optional(),
  limit: z.coerce.number().int().positive().max(100).optional(),
  tagId: z.coerce.number().int().positive().optional(),
  tagIds: z.preprocess(
    (value) => {
      if (typeof value === 'string') {
        if (!value.trim()) return [];
        return value
          .split(',')
          .map((part) => Number(part.trim()))
          .filter((num) => Number.isInteger(num) && num > 0);
      }
      if (Array.isArray(value)) {
        return value
          .map((part) => Number(part))
          .filter((num) => Number.isInteger(num) && num > 0);
      }
      return undefined;
    },
    z.array(z.number().int().positive()).optional(),
  ),
});

export function createRecipeRoutes(db: Database): Router {
  const router = Router();
  const searchIndex = SearchIndex.getInstance(db);
  // Initialize search index in the background (non-blocking)
  // Note: We don't await here to avoid delaying route setup; index will be ready soon
  searchIndex.initialize().catch(console.error);
  const recipeService = new RecipeService(db, searchIndex);

  router.get('/', asyncHandler(async (req, res) => {
    const parsedFilters = recipeFiltersSchema.parse(req.query);
    const normalizedTagIds = parsedFilters.tagIds && parsedFilters.tagIds.length > 0
      ? parsedFilters.tagIds
      : parsedFilters.tagId
        ? [parsedFilters.tagId]
        : undefined;

    const filters = {
      ...parsedFilters,
      tagIds: normalizedTagIds,
    };

    const result = recipeService.list(filters);
    const offset = filters.offset || 0;
    const limit = filters.limit || 50;
    const baseUrl = `${req.protocol}://${req.get('host')}${req.baseUrl}`;

    const meta: any = {
      total: result.total,
      offset,
      limit,
    };

    // Pagination links
    if (offset + limit < result.total) {
      meta.next = `${baseUrl}?offset=${offset + limit}&limit=${limit}`;
    }
    if (offset > 0) {
      meta.prev = `${baseUrl}?offset=${Math.max(0, offset - limit)}&limit=${limit}`;
    }

    res.json({
      success: true,
      data: result.recipes,
      meta,
      error: null,
    });
  }));

  router.get('/search', asyncHandler(async (req, res) => {
    const { q: query, offset = 0, limit = 20 } = req.query;
    if (!query || typeof query !== 'string' || query.trim().length === 0) {
      return res.status(400).json({
        success: false,
        data: null,
        error: 'Query parameter "q" is required',
      });
    }
    await searchIndex.initialize();

    const resultIds = searchIndex.search(query, Math.min(Number(limit) * 2, 100));
    const total = resultIds.length;
    const paginatedIds = resultIds.slice(Number(offset), Number(offset) + Number(limit));
    const hasMore = total > Number(offset) + Number(limit);

    const recipes = paginatedIds
      .map(id => recipeService.get(id))
      .filter((recipe): recipe is NonNullable<typeof recipe> => recipe !== null);

    const baseUrl = `${req.protocol}://${req.get('host')}${req.baseUrl}/search`;
    const meta: any = {
      total,
      offset: Number(offset),
      limit: Number(limit),
      has_more: hasMore,
      next: hasMore ? `${baseUrl}?q=${encodeURIComponent(query)}&offset=${Number(offset) + Number(limit)}&limit=${Number(limit)}` : null,
      prev: Number(offset) > 0 ? `${baseUrl}?q=${encodeURIComponent(query)}&offset=${Math.max(0, Number(offset) - Number(limit))}&limit=${Number(limit)}` : null,
    };

    res.json({ success: true, data: recipes, meta, error: null });
  }));

  router.get('/:id', asyncHandler(async (req, res) => {
    const id = parseInt(req.params.id, 10);
    if (isNaN(id)) {
      res.status(400).json({ success: false, data: null, error: 'Invalid recipe ID' });
      return;
    }
    const recipe = recipeService.get(id);
    if (!recipe) {
      res.status(404).json({ success: false, data: null, error: 'Recipe not found' });
      return;
    }
    res.json({ success: true, data: recipe, error: null });
  }));

  router.post('/', asyncHandler(async (req, res) => {
    const data = createRecipeSchema.parse(req.body);
    const recipe = recipeService.create(data);
    res.status(201).json({ success: true, data: recipe, error: null });
  }));

  router.put('/:id', asyncHandler(async (req, res) => {
    const id = parseInt(req.params.id, 10);
    if (isNaN(id)) {
      res.status(400).json({ success: false, data: null, error: 'Invalid recipe ID' });
      return;
    }
    const data = updateRecipeSchema.parse(req.body);
    const recipe = recipeService.update(id, data);
    if (!recipe) {
      res.status(404).json({ success: false, data: null, error: 'Recipe not found' });
      return;
    }
    res.json({ success: true, data: recipe, error: null });
  }));

  router.delete('/:id', asyncHandler(async (req, res) => {
    const id = parseInt(req.params.id, 10);
    if (isNaN(id)) {
      res.status(400).json({ success: false, data: null, error: 'Invalid recipe ID' });
      return;
    }
    const deleted = recipeService.delete(id);
    if (!deleted) {
      res.status(404).json({ success: false, data: null, error: 'Recipe not found' });
      return;
    }
    res.json({ success: true, data: true, error: null });
  }));

  return router;
}