import type { ToolInput } from "../../core/io/input-types";
import type { ToolResult } from "../../core/io/output-types";
import type { ToolContext } from "../../core/plugins/plugin-types";
import type { TimestampOptions } from "./index";

export async function runTimestampConverter(
  input: ToolInput,
  options: TimestampOptions,
  context?: ToolContext
): Promise<ToolResult> {
  void context;

  const text = (input.text || "").trim();
  if (!text) {
    throw new Error("No input provided.");
  }

  if (options.mode === "timestamp-to-date") {
    let ts = Number(text);
    if (isNaN(ts)) {
      throw new Error("Invalid timestamp. Enter a numeric Unix timestamp.");
    }

    if (options.unit === "seconds") {
      ts = ts * 1000;
    }

    const date = new Date(ts);
    if (isNaN(date.getTime())) {
      throw new Error("Invalid timestamp value.");
    }

    return {
      type: "json",
      value: {
        input: text,
        iso: date.toISOString(),
        utc: date.toUTCString(),
        local: date.toLocaleString(),
        date: date.toISOString().split("T")[0],
        time: date.toISOString().split("T")[1].replace("Z", ""),
        unixSeconds: Math.floor(date.getTime() / 1000),
        unixMillis: date.getTime(),
        dayOfWeek: date.toLocaleDateString("en-US", { weekday: "long" }),
      },
    };
  } else {
    let date: Date;
    if (/^\d{4}-\d{2}-\d{2}(T|\s)/.test(text)) {
      date = new Date(text);
    } else {
      date = new Date(text);
    }

    if (isNaN(date.getTime())) {
      throw new Error("Invalid date string. Use ISO 8601 format like 2024-01-15T12:00:00Z.");
    }

    const unixSeconds = Math.floor(date.getTime() / 1000);
    const unixMillis = date.getTime();

    return {
      type: "json",
      value: {
        input: text,
        iso: date.toISOString(),
        utc: date.toUTCString(),
        unixSeconds: options.unit === "seconds" ? unixSeconds : undefined,
        unixMillis: options.unit === "milliseconds" ? unixMillis : undefined,
        both: {
          seconds: unixSeconds,
          milliseconds: unixMillis,
        },
      },
    };
  }
}