import type { VariableConfig } from "../../lib/config/schema";

/** Splits each `name=value` pair and groups by name - repeats accumulate into an array, which is
 * how a `multiselect` variable is given more than one selection on the command line. */
export function parseVarFlags(pairs: string[]): Record<string, string[]> {
  const grouped: Record<string, string[]> = {};
  for (const pair of pairs) {
    const eq = pair.indexOf("=");
    if (eq === -1) {
      throw new Error(`--var ${pair} is missing '=' - expected --var name=value`);
    }
    const name = pair.slice(0, eq);
    const value = pair.slice(eq + 1);
    (grouped[name] ??= []).push(value);
  }
  return grouped;
}

/** Coerces raw `--var` strings into the JS type each variable expects, ready for
 * `buildVariableSchema(script).safeParse(...)` - the same schema the web form and the
 * `/api/scripts/:id/runs` route already validate against. Variables not present in `grouped`
 * are left out entirely (the caller fills those from `defaultValuesForScript` first). */
export function coerceVariables(
  variables: readonly VariableConfig[],
  grouped: Record<string, string[]>,
): Record<string, unknown> {
  const values: Record<string, unknown> = {};
  const known = new Set(variables.map((v) => v.name));

  for (const name of Object.keys(grouped)) {
    if (!known.has(name)) {
      throw new Error(`--var ${name}=... does not match any variable on this script`);
    }
  }

  for (const variable of variables) {
    const raw = grouped[variable.name];
    if (!raw) continue;

    if (variable.type === "multiselect") {
      values[variable.name] = raw;
      continue;
    }

    if (raw.length > 1) {
      throw new Error(
        `--var ${variable.name}=... was given ${raw.length} times, but '${variable.name}' is not a multiselect variable`,
      );
    }
    const value = raw[0];

    if (variable.type === "boolean") {
      if (value === "true") values[variable.name] = true;
      else if (value === "false") values[variable.name] = false;
      else throw new Error(`--var ${variable.name}=${value} must be 'true' or 'false'`);
    } else if (variable.type === "number") {
      const n = Number(value);
      if (Number.isNaN(n)) {
        throw new Error(`--var ${variable.name}=${value} is not a valid number`);
      }
      values[variable.name] = n;
    } else {
      values[variable.name] = value;
    }
  }

  return values;
}