import type { ProductFilters, ProductSearchResult, SearchProductsResponse } from "./types.js";
import { extractWidthInches, formatWidthInches } from "./product-metrics.js";

export interface ResponseInput {
  query: string;
  filters: ProductFilters;
  limit: number;
  maxSearchPages: number;
  results: ProductSearchResult[];
  filteredOutCount: number;
  warnings: string[];
  now?: () => Date;
}

export function createResponse(input: ResponseInput): SearchProductsResponse {
  return {
    query: input.query,
    filters: input.filters,
    limit: input.limit,
    maxSearchPages: input.maxSearchPages,
    results: input.results,
    filteredOutCount: input.filteredOutCount,
    warnings: input.warnings,
    source: {
      site: "amazon.com",
      scrapedAt: (input.now ?? (() => new Date()))().toISOString(),
      automation: "web-automation/CloakBrowser"
    }
  };
}

function formatFilters(filters: ProductFilters): string {
  const parts = [
    filters.minRating !== undefined ? `rating ${filters.ratingComparison ?? "gte"} ${filters.minRating}` : "",
    filters.minReviews !== undefined ? `reviews ${filters.reviewCountComparison ?? "gte"} ${filters.minReviews}` : "",
    filters.maxPrice !== undefined ? `price <= $${filters.maxPrice}` : "",
    filters.maxUnitPrice !== undefined ? `unit price <= $${filters.maxUnitPrice}` : "",
    filters.minWidthInches !== undefined ? `width ${filters.widthComparison ?? "gte"} ${filters.minWidthInches} inches` : "",
    filters.requirePrime ? "Prime delivery" : "",
    filters.requireFreeDelivery ? "free delivery" : "",
    filters.deliveryBy ? `delivery by ${filters.deliveryBy}` : "",
    filters.sortBy === "price" ? "sort by price" : ""
  ].filter(Boolean);
  return parts.length > 0 ? parts.join(", ") : "none";
}

function compactText(value: string): string {
  return value.replace(/\s+/g, " ").trim();
}

function marker(passes: boolean | undefined, enabled: boolean): string {
  if (!enabled) {
    return "";
  }
  return passes ? " OK" : " NO";
}

function widthCell(product: ProductSearchResult, filters: ProductFilters): string {
  const width = extractWidthInches(product);
  const passes = width !== undefined && (filters.widthComparison === "gt" ? width > (filters.minWidthInches ?? 0) : width >= (filters.minWidthInches ?? 0));
  return `${formatWidthInches(width)}${marker(passes, filters.minWidthInches !== undefined)}`;
}

function primeCell(product: ProductSearchResult, filters: ProductFilters): string {
  if (product.delivery?.prime) {
    return `Prime${marker(true, Boolean(filters.requirePrime))}`;
  }
  return `not verified${marker(false, Boolean(filters.requirePrime))}`;
}

function deliveryCell(product: ProductSearchResult, filters: ProductFilters): string {
  const display = product.delivery?.display ?? "unknown";
  if (!filters.deliveryBy) {
    return display;
  }
  const normalized = display.toLowerCase();
  const passes = filters.deliveryBy === "today"
    ? /\btoday\b|same[- ]day/.test(normalized)
    : filters.deliveryBy === "tomorrow" || filters.deliveryBy === "overnight"
      ? /\btomorrow\b|overnight|next[- ]day|one[- ]day/.test(normalized)
      : normalized.includes(filters.deliveryBy.toLowerCase());
  return `${display}${marker(passes, true)}`;
}

function resultBlocks(products: ProductSearchResult[], filters: ProductFilters): string[] {
  return products.flatMap((product, index) => [
    `${index + 1}. ${compactText(product.title)}`,
    `Price: ${product.price?.display ?? "unknown"}`,
    `Rating: ${product.rating ?? "unknown"} stars`,
    `Reviews: ${product.reviewCount?.toLocaleString("en-US") ?? "unknown"}`,
    `Width: ${widthCell(product, filters)}`,
    `Prime: ${primeCell(product, filters)}`,
    `Delivery: ${compactText(deliveryCell(product, filters))}`,
    `Link: ${product.url}`,
    ""
  ]);
}

function metadataLines(products: ProductSearchResult[]): string[] {
  const lines: string[] = [];
  for (const product of products) {
    const notes = [
      product.missingFields.length > 0 ? `missing ${product.missingFields.join(", ")}` : "",
      product.isSponsored ? "sponsored" : "",
      product.extractionNotes.length > 0 ? product.extractionNotes.join("; ") : ""
    ].filter(Boolean);
    if (notes.length > 0) {
      lines.push(`- ${product.title}: ${notes.join("; ")}`);
    }
  }
  return lines;
}

export function createMarkdownReport(response: SearchProductsResponse): string {
  const lines = [
    `# Amazon Shopping Results`,
    "",
    `Query: ${response.query}`,
    `Filters: ${formatFilters(response.filters)}`,
    `Results returned: ${response.results.length} (filtered out: ${response.filteredOutCount})`,
    response.warnings.length > 0 ? `Warnings: ${response.warnings.join("; ")}` : "",
    "",
    "## Best Matches",
    "",
    response.results.length > 0 ? "" : "No products matched all requested filters.",
    ...resultBlocks(response.results, response.filters),
    "",
    ...metadataLines(response.results)
  ].filter((line) => line !== "");
  return `${lines.join("\n")}\n`;
}