/*
 *   Copyright (C) 2021 Arsen Musayelyan
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package main

import (
	"os"
	"regexp"
	"strconv"
)

// Attempt to match function in config to provided string
func getAction(c *Config, tts *string) (*Action, bool) {
	// For every action in config
	for _, action := range c.Actions {
		// Attempt to compile configured regular expression
		regex, err := regexp.Compile(action.Phrase)
		if err != nil {
			return nil, false
		}
		// Check if string matches action
		matched := regex.MatchString(*tts)
		if matched {
			return &action, true
		}
	}
	return nil, false
}

// Perform action with input
func performAction(a *Action, tts *string, plugins map[string]pluginFunc) (bool, error) {
	// Attempt to compile configured regular expression
	regex, err := regexp.Compile(a.Phrase)
	if err != nil {
		return false, err
	}
	// Find string submatches in string using regular expression
	match := regex.FindStringSubmatch(*tts)
	strExpanded := false
	// Expand instances of $var in action input
	retCmd := os.Expand(a.Input, func(in string) string {
		strExpanded = true
		// Attempt to convert string to integer
		inputInt, err := strconv.Atoi(in)
		// If successful
		if err == nil {
			// If index nonexistent, return empty string
			if len(match) <= inputInt {
				return ""
			}
			// Return match at index
			return match[inputInt]
		}

		// Get subexpression index for input string
		subIndex := regex.SubexpIndex(in)
		// If regex contains subexpression with specified name and match contains index
		if subIndex != -1 && len(match) >= subIndex {
			// Return string matched at index
			return match[subIndex]
		}
		// If nothing worked, put variable back
		return "$" + in
	})

	// If output remained the same and string was expanded
	if a.Input == retCmd && strExpanded {
		return false, nil
	}

	// If type of action is noop, do nothing and return
	if a.Type == "noop" {
		return true, nil
	}

	// Run plugin with input
	plugins[a.Type](retCmd, a.Data)
	return true, nil
}