import Definitions from './lib/option-definitions.mjs'
import ArgvParser from './lib/argv-parser.mjs'
import Option from './lib/option.mjs'
import OutputGrouped from './lib/output-grouped.mjs'
import Output from './lib/output.mjs'

/**
 * @module command-line-args
 */

/**
 * Returns an object containing all option values set on the command line. By default it parses the global  [`process.argv`](https://nodejs.org/api/process.html#process_process_argv) array.
 *
 * Parsing is strict by default - an exception is thrown if the user sets a singular option more than once or sets an unknown value or option (one without a valid [definition](https://github.com/75lb/command-line-args/blob/master/doc/option-definition.md)). To be more permissive, enabling [partial](https://github.com/75lb/command-line-args/wiki/Partial-mode-example) or [stopAtFirstUnknown](https://github.com/75lb/command-line-args/wiki/stopAtFirstUnknown) modes will return known options in the usual manner while collecting unknown arguments in a separate `_unknown` property.
 *
 * @param {module:definition[]} - An array of [OptionDefinition](https://github.com/75lb/command-line-args/blob/master/doc/option-definition.md) objects
 * @param {object} [options] - Options.
 * @param {string[]} [options.argv] - An array of strings which, if present will be parsed instead  of `process.argv`.
 * @param {boolean} [options.partial] - If `true`, an array of unknown arguments is returned in the `_unknown` property of the output.
 * @param {boolean} [options.stopAtFirstUnknown] - If `true`, parsing will stop at the first unknown argument and the remaining arguments returned in `_unknown`. When set, `partial: true` is also implied.
 * @param {boolean} [options.camelCase] - If `true`, options with hypenated names (e.g. `move-to`) will be returned in camel-case (e.g. `moveTo`).
 * @returns {object}
 * @throws `UNKNOWN_OPTION` If `options.partial` is false and the user set an undefined option. The `err.optionName` property contains the arg that specified an unknown option, e.g. `--one`.
 * @throws `UNKNOWN_VALUE` If `options.partial` is false and the user set a value unaccounted for by an option definition. The `err.value` property contains the unknown value, e.g. `5`.
 * @throws `ALREADY_SET` If a user sets a singular, non-multiple option more than once. The `err.optionName` property contains the option name that has already been set, e.g. `one`.
 * @throws `INVALID_DEFINITIONS`
 *   - If an option definition is missing the required `name` property
 *   - If an option definition has a `type` value that's not a function
 *   - If an alias is numeric, a hyphen or a length other than 1
 *   - If an option definition name was used more than once
 *   - If an option definition alias was used more than once
 *   - If more than one option definition has `defaultOption: true`
 *   - If a `Boolean` option is also set as the `defaultOption`.
 * @alias module:command-line-args
 */
function commandLineArgs (optionDefinitions, options) {
  options = options || {}
  if (options.stopAtFirstUnknown) options.partial = true
  optionDefinitions = Definitions.from(optionDefinitions)

  const parser = new ArgvParser(optionDefinitions, {
    argv: options.argv,
    stopAtFirstUnknown: options.stopAtFirstUnknown
  })

  const OutputClass = optionDefinitions.isGrouped() ? OutputGrouped : Output
  const output = new OutputClass(optionDefinitions)

  /* Iterate the parser setting each known value to the output. Optionally, throw on unknowns. */
  for (const argInfo of parser) {
    const arg = argInfo.subArg || argInfo.arg
    if (!options.partial) {
      if (argInfo.event === 'unknown_value') {
        const err = new Error(`Unknown value: ${arg}`)
        err.name = 'UNKNOWN_VALUE'
        err.value = arg
        throw err
      } else if (argInfo.event === 'unknown_option') {
        const err = new Error(`Unknown option: ${arg}`)
        err.name = 'UNKNOWN_OPTION'
        err.optionName = arg
        throw err
      }
    }

    let option
    if (output.has(argInfo.name)) {
      option = output.get(argInfo.name)
    } else {
      option = Option.create(argInfo.def)
      output.set(argInfo.name, option)
    }

    if (argInfo.name === '_unknown') {
      option.set(arg)
    } else {
      option.set(argInfo.value)
    }
  }

  return output.toObject({ skipUnknown: !options.partial, camelCase: options.camelCase })
}

export default commandLineArgs
