package aur

import (
	"encoding/json"
	"errors"
	"fmt"
	"github.com/Jguer/go-alpm"
	"io"
	"net/http"
	"os"
	"os/exec"
	"sort"
	"strings"
)

// TarBin describes the default installation point of tar command
// Probably will replace untar with code solution
const TarBin string = "/usr/bin/tar"

// BaseURL givers the AUR default address
const BaseURL string = "https://aur.archlinux.org"

// MakepkgBin describes the default installation point of makepkg command
const MakepkgBin string = "/usr/bin/makepkg"

// Result describes an AUR package
type Result struct {
	ID             int         `json:"ID"`
	Name           string      `json:"Name"`
	PackageBaseID  int         `json:"PackageBaseID"`
	PackageBase    string      `json:"PackageBase"`
	Version        string      `json:"Version"`
	Description    string      `json:"Description"`
	URL            string      `json:"URL"`
	NumVotes       int         `json:"NumVotes"`
	Popularity     float32     `json:"Popularity"`
	OutOfDate      interface{} `json:"OutOfDate"`
	Maintainer     string      `json:"Maintainer"`
	FirstSubmitted int         `json:"FirstSubmitted"`
	LastModified   int         `json:"LastModified"`
	URLPath        string      `json:"URLPath"`
	Depends        []string    `json:"Depends"`
	MakeDepends    []string    `json:"MakeDepends"`
	OptDepends     []string    `json:"OptDepends"`
	Conflicts      []string    `json:"Conflicts"`
	License        []string    `json:"License"`
	Keywords       []string    `json:"Keywords"`
}

// Query describes an AUR json Query
type Query struct {
	Resultcount int      `json:"resultcount"`
	Results     []Result `json:"results"`
	Type        string   `json:"type"`
	Version     int      `json:"version"`
}

// Editor gives the default system editor, uses vi in last case
var Editor = "vi"

func init() {
	if os.Getenv("EDITOR") != "" {
		Editor = os.Getenv("EDITOR")
	}
}

func (r Query) Len() int {
	return len(r.Results)
}

func (r Query) Less(i, j int) bool {
	return r.Results[i].NumVotes > r.Results[j].NumVotes
}

func (r Query) Swap(i, j int) {
	r.Results[i], r.Results[j] = r.Results[j], r.Results[i]
}

func downloadFile(filepath string, url string) (err error) {
	// Create the file
	out, err := os.Create(filepath)
	if err != nil {
		return err
	}
	defer out.Close()

	// Get the data
	resp, err := http.Get(url)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	// Writer the body to file
	_, err = io.Copy(out, resp.Body)
	if err != nil {
		return err
	}

	return nil
}

// getJSON handles JSON retrieval and decoding to struct
func getJSON(url string, target interface{}) error {
	r, err := http.Get(url)
	if err != nil {
		return err
	}
	defer r.Body.Close()

	return json.NewDecoder(r.Body).Decode(target)
}

// Search returns an AUR search
func Search(pkg string, sortS bool) (r Query, err error) {
	err = getJSON("https://aur.archlinux.org/rpc/?v=5&type=search&arg="+pkg, &r)
	if sortS {
		sort.Sort(r)
	}
	return
}

// Info returns an AUR search with package details
func Info(pkg string) (r Query, err error) {
	err = getJSON("https://aur.archlinux.org/rpc/?v=5&type=info&arg[]="+pkg, &r)
	return
}

// Install sends system commands to make and install a package from pkgName
func Install(pkg string, baseDir string, conf alpm.PacmanConfig, flags ...string) (err error) {
	info, err := Info(pkg)
	if err != nil {
		return
	}

	if info.Resultcount == 0 {
		return errors.New("Package '" + pkg + "' does not exist")
	}

	info.Results[0].Install(baseDir, conf, flags...)
	return err
}

// Install handles install from Result
func (a Result) Install(baseDir string, conf alpm.PacmanConfig, flags ...string) (err error) {
	// No need to use filepath.separators because it won't run on inferior platforms
	err = os.MkdirAll(baseDir+"builds", 0755)
	if err != nil {
		fmt.Println(err)
		return
	}

	tarLocation := baseDir + a.Name + ".tar.gz"
	defer os.Remove(baseDir + a.Name + ".tar.gz")

	err = downloadFile(tarLocation, BaseURL+a.URLPath)
	if err != nil {
		return
	}

	err = exec.Command(TarBin, "-xf", tarLocation, "-C", baseDir).Run()
	if err != nil {
		return
	}
	defer os.RemoveAll(baseDir + a.Name)
	_, err = a.Dependencies(conf)
	if err != nil {
		return
	}

	fmt.Print("\033[1m\x1b[32m==> Edit PKGBUILD? (y/n)\033[0m")
	var response string
	fmt.Scanln(&response)
	if strings.ContainsAny(response, "y & Y") {
		editcmd := exec.Command(Editor, baseDir+a.Name+"/"+"PKGBUILD")
		editcmd.Stdout = os.Stdout
		editcmd.Stderr = os.Stderr
		editcmd.Stdin = os.Stdin
		err = editcmd.Run()
	}

	err = os.Chdir(baseDir + a.Name)
	if err != nil {
		return
	}
	var args string
	if len(flags) != 0 {
		args = fmt.Sprintf(" %s", strings.Join(flags, " "))
	}
	makepkgcmd := exec.Command(MakepkgBin, "-sri"+args)
	makepkgcmd.Stdout = os.Stdout
	makepkgcmd.Stderr = os.Stderr
	makepkgcmd.Stdin = os.Stdin
	err = makepkgcmd.Run()

	return
}

// Dependencies returns package dependencies splitting between AUR results and Repo Results not installed
func (a Result) Dependencies(conf alpm.PacmanConfig) (final []string, err error) {
	f := func(c rune) bool {
		return c == '>' || c == '<' || c == '=' || c == ' '
	}
	info, err := Info(a.Name)
	if err != nil {
		return
	}

	if len(info.Results) == 0 {
		return final, errors.New("Failed to get deps from RPC")
	}

	var found bool
	for _, deps := range info.Results[0].MakeDepends {
		fields := strings.FieldsFunc(deps, f)

		if found, err = IspkgInstalled(fields[0]); found {
			if err != nil {
				return
			}
			continue
		}

		if found, err = IspkgInRepo(fields[0], conf); !found {
			if err != nil {
				return
			}
			final = append(final, fields[0])
		}
	}

	for _, deps := range info.Results[0].Depends {
		fields := strings.FieldsFunc(deps, f)

		if found, err = IspkgInstalled(fields[0]); found {
			if err != nil {
				return
			}
			continue
		}

		if found, err = IspkgInRepo(fields[0], conf); !found {
			if err != nil {
				return
			}
			final = append(final, fields[0])
		}
	}
	return
}

// IspkgInstalled returns true if pkgName is installed
func IspkgInstalled(pkgName string) (bool, error) {
	h, err := alpm.Init("/", "/var/lib/pacman")
	defer h.Release()
	if err != nil {
		return false, err
	}

	localDb, err := h.LocalDb()
	if err != nil {
		return false, err
	}

	for _, pkg := range localDb.PkgCache().Slice() {
		if pkg.Name() == pkgName {
			return true, nil
		}
	}

	return false, nil
}

// IspkgInRepo returns true if pkgName is in a synced repo
func IspkgInRepo(pkgName string, conf alpm.PacmanConfig) (bool, error) {
	h, err := conf.CreateHandle()
	defer h.Release()
	if err != nil {
		return false, err
	}

	dbList, _ := h.SyncDbs()
	for _, db := range dbList.Slice() {
		for _, pkg := range db.PkgCache().Slice() {
			if pkg.Name() == pkgName {
				return true, nil
			}
		}
	}
	return false, nil
}