import { normalizeRateDisplay } from "../../shared/rate-normalizer";
import { escapeCsvCell } from "../../shared/csv";
import type { MarketRecord } from "./types";

type CsvColumn = {
  header: string;
  readValue: (record: MarketRecord) => string;
};

const FALLBACK_BASE_COLUMNS: CsvColumn[] = [
  {
    header: "达人ID",
    readValue: (record: MarketRecord) => record.authorId
  },
  {
    header: "达人名称",
    readValue: (record: MarketRecord) => record.authorName
  },
  {
    header: "地区",
    readValue: (record: MarketRecord) => record.location ?? ""
  },
  {
    header: "21-60s报价",
    readValue: (record: MarketRecord) => record.price21To60s ?? ""
  }
];

const RATE_COLUMNS: CsvColumn[] = [
  {
    header: "单视频看后搜率",
    readValue: (record: MarketRecord) =>
      record.rates?.singleVideoAfterSearchRate
        ? normalizeRateDisplay(record.rates.singleVideoAfterSearchRate)
        : ""
  },
  {
    header: "个人视频看后搜率",
    readValue: (record: MarketRecord) =>
      record.rates?.personalVideoAfterSearchRate
        ? normalizeRateDisplay(record.rates.personalVideoAfterSearchRate)
        : ""
  }
];

export function buildMarketCsv(records: MarketRecord[]): string {
  const baseColumns = buildBaseColumns(records);
  const csvColumns = [...baseColumns, ...RATE_COLUMNS];
  const headerLine = csvColumns.map((column) => column.header).join(",");
  const rowLines = records.map((record) =>
    csvColumns.map((column) => escapeCsvCell(column.readValue(record))).join(",")
  );

  return [headerLine, ...rowLines].join("\n");
}

function buildBaseColumns(records: MarketRecord[]): CsvColumn[] {
  const orderedHeaders: string[] = [];
  const seenHeaders = new Set<string>();

  records.forEach((record) => {
    Object.keys(record.exportFields ?? {}).forEach((header) => {
      if (seenHeaders.has(header)) {
        return;
      }

      seenHeaders.add(header);
      orderedHeaders.push(header);
    });
  });

  if (orderedHeaders.length === 0) {
    return FALLBACK_BASE_COLUMNS;
  }

  return orderedHeaders.map((header) => ({
    header,
    readValue: (record: MarketRecord) => record.exportFields?.[header] ?? ""
  }));
}