package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"io/ioutil"
	"os"

	"github.com/fatih/color"
	"gitlab.com/EternalWanderer/dice-roller/Dice"
)

var (
	path, skillString, saveString, statString      string
	modifier, diceThrows, surfaces                 int
	X, Y                                           int
	char                                           Character
	skillMap                                       = make(map[string]int)
	statMap                                        = make(map[string]int)
	advantage, disadvantage, stat_list, skill_list bool
)

func parseFlags() {
	flag.StringVar(&path, "file", "stats.json", "Used to point to character sheet")
	flag.StringVar(&path, "f", "stats.json", "Used to point to character sheet")
	flag.StringVar(&skillString, "skill", "", "Skill to parse")
	flag.StringVar(&statString, "stat", "", "Stat check")
	flag.StringVar(&saveString, "save", "", "Saving throw to... throw")

	flag.BoolVar(&advantage, "advantage", advantage, "Roll with advantage")
	flag.BoolVar(&disadvantage, "disadvantage", disadvantage, "Roll with disadvantage")

	flag.BoolVar(&stat_list, "stat-list", false, "Print list of stats, can also be used with -save flag")
	flag.BoolVar(&skill_list, "skill-list", false, "Print list of skills to be used in combination with the -skill flag")

	flag.Parse()
}

func isError(err error) bool {
	if err != nil {
		fmt.Println(err.Error())
	}
	return (err != nil)
}

func readJson() {
	fmt.Println("Opening file:", path)
	var file, err = os.Open(path)
	if isError(err) {
		return
	}
	defer file.Close()

	byteValue, _ := ioutil.ReadAll(file)
	json.Unmarshal(byteValue, &char)
}

func initMaps() {
	for i := 0; i < len(char.Skills); i++ {
		skillMap[char.Skills[i].SkillName] = i
	}

	for i := 0; i < len(char.Stats); i++ {
		statMap[char.Stats[i].StatName] = i
	}
}

func main() {
	parseFlags()
	readJson()
	initMaps()

	switch {
	case stat_list:
		for i := 0; i < len(char.Stats); i++ {
			fmt.Println(char.Stats[i].StatName)
		}
	case skill_list:
		for i := 0; i < len(char.Skills); i++ {
			fmt.Println(char.Skills[i].SkillName)
		}
	case advantage && disadvantage:
		fmt.Println("You can't roll with both advantage and disadvantage")
		os.Exit(1)
	case len(saveString) > 0:
		result := savingThrow(getStat(saveString))
		if advantage {
			color.Yellow("Rolling %s saving throw with advantage...", saveString)
			fmt.Printf("x: %d\ty: %d\n", X, Y)
			color.Green("%d\n", result)
		} else if disadvantage {
			color.Yellow("Rolling %s saving throw with disadvantage...", saveString)
			fmt.Printf("x: %d\ty: %d\n", X, Y)
			color.Red("%d\n", result)
		} else {
			color.Yellow("Rolling %s saving throw...", saveString)
			color.Green("%d\n", result)
		}

	case len(skillString) > 0:
		result := skillCheck(getSkill(skillString))
		if advantage {
			color.Yellow("Rolling %s saving throw with advantage...", skillString)
			fmt.Printf("x: %d\ty: %d\n", X, Y)
			color.Green("%d\n", result)
		} else if disadvantage {
			color.Yellow("Rolling %s saving throw with disadvantage...", skillString)
			fmt.Printf("x: %d\ty: %d\n", X, Y)
			color.Red("%d\n", result)
		} else {
			color.Yellow("Rolling %s check...", skillString)
			color.Green("%d\n", result)
		}

	case len(statString) > 0:
		result := statCheck(getStat(statString))
		if advantage {
			color.Yellow("Rolling %s check with advantage...", statString)
			fmt.Printf("x: %d\ty: %d\n", X, Y)
			color.Green("%d\n", result)
		} else if disadvantage {
			color.Yellow("Rolling %s check with disadvantage...", statString)
			fmt.Printf("x: %d\ty: %d\n", X, Y)
			color.Red("%d\n", result)
		} else {
			color.Yellow("Rolling %s check...", statString)
			color.Green("%d\n", result)
		}

	default:
		flag.Usage()
	}
}

func getProficiency() int {
	// https://worldbuildersjunction.com/what-is-proficiency-bonus-in-dd-5e-how-it-works-calculated/
	return (char.Misc.Level-1)/4 + 2
}

func getSkill(skillName string) Skill {
	return char.Skills[skillMap[skillName]]
}

func getStat(statName string) Stat {
	return char.Stats[statMap[statName]]
}

func getModifier(stat Stat) int {
	// https://worldbuildersjunction.com/dungeon-and-dragons-ability-scores-explained-for-beginners/
	return (stat.Score - 10) / 2
}

func rollDice() int {
	var die int
	switch {
	case advantage:
		die, X, Y = Dice.Advantage()
	case disadvantage:
		die, X, Y = Dice.Disadvantage()
	default:
		die = Dice.SimpleCast()
	}
	switch die {
	case 20:
		color.Magenta("Natural 20!\n")
	case 1:
		color.Magenta("Natural 1!\n")
	}
	return die
}

func statCheck(stat Stat) int {
	return rollDice() + getModifier(stat)

}

func savingThrow(stat Stat) int {
	die := rollDice()

	if stat.Proficient {
		die += getProficiency()
	}
	return die + getModifier(stat)
}

func skillCheck(skill Skill) int {
	var die int
	die = rollDice()

	die += getModifier(getStat(skill.BaseStat))

	switch {
	case skill.Expertise:
		die += getProficiency() * 2
	case skill.Proficient:
		die += getProficiency()
	}
	return die
}