import { tool } from "@opencode-ai/plugin";
import path from "path";

const SCRIPTS_DIR = (ctx: { worktree: string }) =>
  path.join(ctx.worktree, "scripts");

async function runPython(
  ctx: { worktree: string },
  fn: string,
  args: Record<string, unknown>,
): Promise<string> {
  const scriptPath = path.join(SCRIPTS_DIR(ctx), "backtest_engine.py");
  const argsJson = JSON.stringify(args);
  const result = await Bun.$`python3 ${scriptPath} ${fn} ${argsJson}`.text();
  return result.trim();
}

export const run = tool({
  description: "Run a backtest for a trading strategy on specified stock universe and period",
  args: {
    strategy_name: tool.schema.string().optional().describe("Name of a predefined strategy, or omit to use custom rules"),
    entry_rule: tool.schema.string().optional().describe("Custom entry condition (Python expression using df columns like close, ma20, ma60, volume, etc.)"),
    exit_rule: tool.schema.string().optional().describe("Custom exit condition (Python expression) or 'stop_loss:0.05,take_profit:0.15,max_hold:20'"),
    universe: tool.schema.enum(["hs300", "zz500", "all", "custom"]).default("hs300").describe("Stock universe to test on"),
    symbols: tool.schema.string().optional().describe("Comma-separated stock codes for custom universe"),
    start_date: tool.schema.string().default("20210101").describe("Start date YYYYMMDD"),
    end_date: tool.schema.string().default("20251231").describe("End date YYYYMMDD"),
  },
  async execute(args, context) {
    return runPython(context, "run", args);
  },
});

export const predefined = tool({
  description: "List all predefined backtest strategies with descriptions",
  args: {},
  async execute(args, context) {
    return runPython(context, "predefined", args);
  },
});

export const compare = tool({
  description: "Compare multiple predefined strategies on the same universe and period",
  args: {
    strategies: tool.schema.string().describe("Comma-separated strategy names to compare"),
    universe: tool.schema.enum(["hs300", "zz500", "all"]).default("hs300").describe("Stock universe"),
    start_date: tool.schema.string().default("20210101").describe("Start date YYYYMMDD"),
    end_date: tool.schema.string().default("20251231").describe("End date YYYYMMDD"),
  },
  async execute(args, context) {
    return runPython(context, "compare", args);
  },
});