package modlist

import (
	"encoding/json"
	"os"
	"regexp"
	"strings"

	"github.com/charmbracelet/log"
)

// fileRegex matches
const fileRegex string = "([\\w\\s-]+)_([0-9.]+)\\.zip"

/// Modlist types and related functions.

// Mod holds data about a single mod.
type Mod struct {
	Name    string `json:"name"`
	Enabled bool   `json:"enabled"`
}

// Modlist holds a slice of mods.
type Modlist struct {
	dir  string
	Mods []Mod `json:"mods"`
}

/// Non exported functions

func (modlist *Modlist) setModStatus(name string, status bool) {
	for i := range modlist.Mods {
		mod := &modlist.Mods[i]
		if mod.Name == name && mod.Enabled != status {
			mod.Enabled = status
			log.Debugf("Setting status of mod %s to %v", mod.Name, mod.Enabled)
		}
	}
}

func (modlist *Modlist) setAllStatus(status bool) {
	for i := range modlist.Mods {
		mod := &modlist.Mods[i]
		mod.Enabled = status
		log.Debugf("Setting status of mod %s to %v", mod.Name, mod.Enabled)
	}
}

// EnableMod enables the given mod.
func (modlist *Modlist) EnableMod(name string) {
	modlist.setModStatus(name, true)
}

// EnableMods enables the given mods.
func (modlist *Modlist) EnableMods(names ...string) {
	for _, name := range names {
		modlist.EnableMod(name)
	}
}

// DisableMod disables the given mod.
func (modlist *Modlist) DisableMod(name string) {
	modlist.setModStatus(name, false)
}

// DisableMods disables the given mods.
func (modlist *Modlist) DisableMods(names ...string) {
	for _, name := range names {
		modlist.DisableMod(name)
	}
}

// EnableAll enables all mods.
func (modlist *Modlist) EnableAll() {
	modlist.setAllStatus(true)
}

// DisableAll disables all mods.
func (modlist *Modlist) DisableAll() {
	modlist.setAllStatus(false)
}

// HasMod reports if a modlist has a mod with name `s`
func (modlist *Modlist) HasMod(s string) bool {
	for _, mod := range modlist.Mods {
		if mod.Name == s {
			return true
		}
	}
	return false
}

// HasMod reports if a modlist has an enabled mod with name `s`
func (modlist *Modlist) HasModEnabled(s string) bool {
	for _, mod := range modlist.Mods {
		if mod.Name == s && mod.Enabled {
			return true
		}
	}
	return false
}

// Print out each mod and its status.
func (modlist *Modlist) Print(prefix string) {
	log.Info(prefix + ": {")
	for _, mod := range modlist.Mods {
		var endis string
		// I wish go had a ternary so this could all be in one line
		if mod.Enabled {
			endis = "en"
		} else {
			endis = "dis"
		}
		log.Infof("\t%s: %sabled,", mod.Name, endis)
	}
	log.Info("}")
}

func (modlist *Modlist) String() {
	modlist.Print("mods")
}

// AddModsNotInList finds mod archives in the mod folder that aren't in the modlist, and adds them.
func (modlist *Modlist) AddModsNotInList(state bool) error {
	r := regexp.MustCompile(fileRegex)

	files, err := os.ReadDir(modlist.dir)
	if err != nil {
		return err
	}

	for _, file := range files {
		if strings.HasSuffix(file.Name(), ".zip") && !file.IsDir() {
			groups := r.FindAllStringSubmatch(file.Name(), -1)
			name := groups[0][1]
			version := groups[0][2]

			if !modlist.HasMod(name) {
				log.Infof("Found %s not in modlist, adding v%s in disabled state.", name, version)
				modlist.Mods = append(modlist.Mods, Mod{
					Name:    name,
					Enabled: state,
				})
			}
		}
	}

	return nil
}

// RemoveModsNotInFolder removes mods from the modlist if a corresponding
// zip file cannot be found in the mods dir.
func (modlist *Modlist) RemoveModsNotInFolder() error {
	for i, mod := range modlist.Mods {
		in, err := isModInFolder(mod.Name, modlist.dir)
		if !in && err == nil {
			log.Warnf("Zip file for %s could not be found, removing!", mod.Name)
			// mods.Mods[i] = nil
			modlist.Mods = append(modlist.Mods[:i], modlist.Mods[i+1:]...)
		} else if err != nil {
			return err
		}
	}

	return nil
}

/// Functions related to the modlist but that shouldn't be attached to the types

func isModInFolder(modname, modsdir string) (bool, error) {
	if modname == "base" {
		return true, nil
	}

	// TODO: try for less O(n)
	files, err := os.ReadDir(modsdir)
	if err != nil {
		return false, err
	}

	for _, file := range files {
		if strings.HasPrefix(file.Name(), modname) {
			return true, nil
		}
	}

	return false, nil
}

// WriteToFile writes the modlist to the given filename.
func WriteToFile(filename string, mods *Modlist) error {
	data, err := json.MarshalIndent(&mods, "", "  ")
	if err != nil {
		return err
	}

	os.WriteFile(filename, data, os.FileMode(0744))
	log.Infof("Wrote modlist to file %s.", filename)
	return nil
}

// ReadFromFile reads the modlist from the given filename.
func ReadFromFile(filename, modsdir string) (Modlist, error) {
	var mods Modlist = Modlist{
		dir: modsdir,
	}

	data, err := os.ReadFile(filename)
	if err != nil {
		return Modlist{}, err
	}

	err = json.Unmarshal(data, &mods)
	if err != nil {
		return Modlist{}, err
	}

	log.Infof("Read modlist from file %s.", filename)
	return mods, nil
}