/**
 * Builds structured scan reports for LLM Agent consumption.
 * Output is a readable markdown text that the Agent can analyze and act on.
 */
import type { BacktestRow, StrategyRow } from "../db/repositories.js";
import type { ScanReport, StrategyScanEntry, SymbolNewsResult } from "./types.js";

/**
 * Build a scan report from strategies, news results, and backtest history.
 * The report is structured for LLM consumption with clear sections.
 */
export function buildScanReport(
  scanId: string,
  strategies: StrategyRow[],
  newsResults: SymbolNewsResult[],
  backtestMap: Map<string, BacktestRow[]>,
): ScanReport {
  const newsLookup = new Map<string, SymbolNewsResult>();
  for (const nr of newsResults) {
    newsLookup.set(nr.symbol, nr);
  }

  const entries: StrategyScanEntry[] = [];

  for (const strategy of strategies) {
    const symbols = parseJsonArray(strategy.symbols);
    if (symbols.length === 0) continue;

    const symbolData: SymbolNewsResult[] = [];
    let significantNewsCount = 0;

    for (const sym of symbols) {
      const nr = newsLookup.get(sym);
      if (nr) {
        symbolData.push(nr);
        significantNewsCount += nr.news.length;
      } else {
        symbolData.push({ symbol: sym, market: "crypto", news: [] });
      }
    }

    const backtests = backtestMap.get(strategy.id) ?? [];
    const latest = backtests[0];

    entries.push({
      strategyId: strategy.id,
      strategyName: strategy.name,
      level: strategy.level ?? "L0",
      symbols,
      lastBacktest: latest
        ? {
            totalReturn: latest.total_return ?? undefined,
            sharpe: latest.sharpe ?? undefined,
            maxDrawdown: latest.max_drawdown ?? undefined,
          }
        : undefined,
      symbolData,
      significantNewsCount,
    });
  }

  return {
    scanId,
    scannedAt: new Date().toISOString(),
    strategiesScanned: entries.length,
    totalNewsFound: entries.reduce((sum, e) => sum + e.significantNewsCount, 0),
    entries,
  };
}

/** Format a ScanReport as readable markdown for the LLM Agent. */
export function formatScanReportMarkdown(report: ScanReport): string {
  const lines: string[] = [];
  const date = report.scannedAt.slice(0, 10);

  lines.push(`## 每日策略扫描报告 — ${date}`);
  lines.push("");
  lines.push(
    `共扫描 ${report.strategiesScanned} 个策略，发现 ${report.totalNewsFound} 条相关新闻。`,
  );
  lines.push("");

  if (report.entries.length === 0) {
    lines.push("暂无活跃策略。请先通过 skill_fork 或手动创建策略。");
    return lines.join("\n");
  }

  for (const entry of report.entries) {
    lines.push(`### ${entry.strategyName} (${entry.level})`);
    lines.push(`- 标的: ${entry.symbols.join(", ")}`);

    if (entry.lastBacktest) {
      const bt = entry.lastBacktest;
      const parts: string[] = [];
      if (bt.totalReturn != null) parts.push(`总收益 ${(bt.totalReturn * 100).toFixed(1)}%`);
      if (bt.sharpe != null) parts.push(`夏普 ${bt.sharpe.toFixed(2)}`);
      if (bt.maxDrawdown != null) parts.push(`最大回撤 ${(bt.maxDrawdown * 100).toFixed(1)}%`);
      if (parts.length > 0) lines.push(`- 最近回测: ${parts.join(", ")}`);
    }

    for (const sd of entry.symbolData) {
      if (sd.currentPrice != null) {
        const change =
          sd.priceChange24h != null
            ? ` (24h ${sd.priceChange24h >= 0 ? "+" : ""}${sd.priceChange24h.toFixed(1)}%)`
            : "";
        lines.push(`- ${sd.symbol} 当前价格: $${sd.currentPrice.toFixed(2)}${change}`);
      }

      if (sd.news.length > 0) {
        lines.push(`- 相关新闻 (${sd.symbol}):`);
        for (const n of sd.news.slice(0, 5)) {
          const sentiment = n.sentiment ? `[${n.sentiment}] ` : "";
          const age = formatAge(n.publishedAt);
          lines.push(`  ${sentiment}${n.title} (${n.source}, ${age})`);
        }
      }
    }

    if (entry.significantNewsCount === 0) {
      lines.push("- 无重大新闻");
    }

    lines.push("");
  }

  // Summary section
  const strategiesWithNews = report.entries.filter((e) => e.significantNewsCount > 0);
  if (strategiesWithNews.length > 0) {
    lines.push("### 需要关注的策略");
    for (const e of strategiesWithNews) {
      lines.push(
        `- ${e.strategyName}: ${e.significantNewsCount} 条相关新闻，建议分析影响并考虑是否需要优化`,
      );
    }
  } else {
    lines.push("### 汇总");
    lines.push("所有策略标的无重大新闻变动，无需调整。");
  }

  return lines.join("\n");
}

// ── Helpers ───────────────────────────────────────────────────────────────

function parseJsonArray(json: string | null | undefined): string[] {
  if (!json) return [];
  try {
    const arr = JSON.parse(json);
    return Array.isArray(arr) ? arr.filter((v): v is string => typeof v === "string") : [];
  } catch {
    return [];
  }
}

function formatAge(isoDate: string): string {
  const ms = Date.now() - new Date(isoDate).getTime();
  const hours = Math.floor(ms / 3_600_000);
  if (hours < 1) return `${Math.floor(ms / 60_000)}m ago`;
  if (hours < 24) return `${hours}h ago`;
  return `${Math.floor(hours / 24)}d ago`;
}