package main

import (
	"bufio"
	"fmt"
	"io"
	"io/fs"
	"math"
	"os"
	"time"

	"errors"
	"os/exec"
	"strings"

	"github.com/goccy/go-yaml"
	"github.com/jwalton/gchalk"
	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
	"github.com/spf13/pflag"
	"github.com/thoas/go-funk"
)

type PackageManager struct {
	Name string
}

func (pm *PackageManager) List() (packages []string, err error) {
	switch pm.Name {
	case "pacman":
		out, err := exec.Command("pacman", "-Sql").Output()
		if err != nil {
			return nil, err
		}
		return strings.Split(string(out), "\n"), nil

	case "apt-get":
		out, err := exec.Command("apt-cache", "pkgnames", "-g").Output()
		if err != nil {
			return nil, err
		}
		return strings.Split(string(out), "\n"), nil

	case "tdnf", "dnf", "yum":
		out, err := exec.Command(pm.Name, "list", "available").Output()
		if err != nil {
			return nil, err
		}
		return funk.Map(strings.Split(string(out), "\n"), func(p string) string {
			return strings.SplitN(p, " ", 1)[0]
		}).([]string), nil

	case "brew": // please no
		out, err := exec.Command("brew", "formulae").Output()
		if err != nil {
			return nil, err
		}
		return strings.Split(string(out), "\n"), nil

	default:
		return nil, errors.New("Unknown package manager " + pm.Name)
	}
}

func (pm *PackageManager) ListInstalled() (packages []string, err error) {
	switch pm.Name {
	case "pacman":
		out, err := exec.Command("pacman", "-Qq").Output()
		if err != nil {
			return nil, err
		}
		return strings.Split(string(out), "\n"), nil

	case "apt-get":
		out, err := exec.Command("dpkg-query", "-f", "${Package}\n", "-W").Output()
		if err != nil {
			return nil, err
		}
		return strings.Split(string(out), "\n"), nil

	case "tdnf", "dnf", "yum":
		out, err := exec.Command(pm.Name, "list", "installed").Output()
		if err != nil {
			return nil, err
		}
		return funk.Map(strings.Split(string(out), "\n"), func(p string) string {
			return strings.SplitN(p, " ", 1)[0]
		}).([]string), nil

	case "brew": // please no
		out, err := exec.Command("brew", "list", "--formula").Output()
		if err != nil {
			return nil, err
		}
		return strings.Split(string(out), "\n"), nil

	default:
		return nil, errors.New("Unknown package manager " + pm.Name)
	}
}

func (pm *PackageManager) Install(pkg string) error {
	switch pm.Name {
	case "pacman":
		return executeCommandWithFormatting("pacman", "-S", "--noconfirm", pkg)

	case "apt-get":
		return executeCommandWithFormatting("apt-get", "install", "-y", pkg)

	case "tdnf", "dnf", "yum":
		return executeCommandWithFormatting(pm.Name, "install", "-y", pkg)

	case "brew": // please no
		return executeCommandWithFormatting("brew", "install", pkg)

	default:
		return errors.New("Unknown package manager " + pm.Name)
	}
}

func (pm *PackageManager) Remove(pkg string) error {
	switch pm.Name {
	case "pacman":
		exec.Command("pacman", "-R", pkg).Run()

	case "apt-get":
		err := exec.Command("apt-get", "remove", pkg).Run()
		if err != nil {
			return err
		}

	case "tdnf", "dnf", "yum":
		err := exec.Command(pm.Name, "remove", pkg).Run()
		if err != nil {
			return err
		}

	case "brew": // please no
		err := exec.Command("brew", "remove", pkg).Run()
		if err != nil {
			return err
		}

	default:
		return errors.New("Unknown package manager " + pm.Name)
	}
	return nil
}

func executeCommandWithFormatting(command string, args ...string) error {
	cmd := exec.Command(command, args...)
	cmd.Env = append(cmd.Env, "LC_ALL=C.UTF-8")
	stdout, err := cmd.StdoutPipe()
	checkError(err)
	stderr, err := cmd.StderrPipe()
	checkError(err)
	stdoutReader := bufio.NewReader(stdout)
	stderrReader := bufio.NewReader(stderr)
	ch := make(chan uint8)
	go func() {
		for {
			line, err := stdoutReader.ReadString('\n')
			if err == io.EOF {
				break
			} else {
				checkError(err)
			}
			delim := gchalk.Gray("│") + gchalk.Blue("   |")
			fmt.Println(delim, strings.TrimSpace(line))
		}
		ch <- 0
	}()
	go func() {
		for {
			line, err := stderrReader.ReadString('\n')
			if err == io.EOF {
				break
			} else {
				checkError(err)
			}
			delim := gchalk.Gray("│") + gchalk.Red("   |")
			fmt.Println(delim, strings.TrimSpace(line))
		}
		ch <- 0
	}()
	err = cmd.Start()
	if err != nil {
		return err
	}
	<-ch
	<-ch
	return cmd.Wait()
}

func commandExists(cmd string) bool {
	command := exec.Command(cmd)
	err := command.Start()
	return err == nil
}

func detectPackageManager() (manager string) {
	managers := []string{"pacman", "apt-get", "tdnf", "dnf", "yum", "brew"}
	for _, manager := range managers {
		if commandExists(manager) {
			return manager
		}
	}
	return ""
}

func terminateWithError(err error) {
	log.Fatal().Err(err).Msg("")
}

func checkUserError(err error) {
	if err != nil {
		terminateWithError(err)
	}
}

func checkError(err error) {
	if err != nil {
		log.Panic().Err(err).Msg("")
	}
}

func executeRunlevel(runlevel string, tasks []string, shell string) {
	fmt.Printf("# Running runlevel '%s'\n", runlevel)
	for _, task := range tasks {
		fmt.Println(gchalk.Gray("│ # Running task: " + task))
		checkUserError(executeCommandWithFormatting(shell, "-c", task))
	}
}

func main() {
	start := time.Now()
	log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
	var configData []byte
	if cfg := *pflag.StringP("config", "c", "", "Provide a path to an alternative config file"); cfg == "" {
		rawConfig, err := os.ReadFile("polymer.yml")
		if err == fs.ErrNotExist {
			rawConfig, err = os.ReadFile("polymer.yaml")
			if err == fs.ErrNotExist {
				log.Fatal().Msg("Neither polymer.yml or polymer.yaml were found. Aborting.")
			} else if err != nil {
				log.Panic().Err(err).Msg("")
			}
		} else if err != nil {
			log.Panic().Err(err).Msg("")
		}
		configData = rawConfig
	} else {
		rawConfig, err := os.ReadFile(cfg)
		if err == fs.ErrNotExist {
			log.Fatal().Msg("Config file " + cfg + " was not found. Aborting.")
		} else if err != nil {
			log.Panic().Err(err).Msg("")
		}
		configData = rawConfig
	}
	var tasks Config
	yaml.Unmarshal(configData, &tasks)
	if tasks.Shell == "" {
		tasks.Shell = "/bin/sh"
	}
	pmName := ""
	if len(tasks.Packages) > 0 {
		pmName = detectPackageManager()
		if pmName == "" {
			log.Fatal().Msg("No supported package manager (pacman, apt-get, yum, dnf, tdnf, brew) was found!")
		}
	}
	executeRunlevel("init", tasks.Execute.Init, tasks.Shell)
	pm := PackageManager{Name: pmName}
	fmt.Printf("\n# Installing packages: '%s'\n", strings.Join(tasks.Packages, ", "))
	fmt.Println(gchalk.Gray("│ # Invoking " + pmName))
	checkUserError(pm.Install(strings.Join(tasks.Packages, "")))
	fmt.Printf(
		gchalk.Green("# Finished with 0 errors in %g seconds!\n"),
		math.Round(time.Since(start).Seconds()*1000)/1000,
	)
}

type Services struct {
	Stop        []string `yaml:"stop"`
	Start       []string `yaml:"start"`
	Enable      []string `yaml:"enable"`
	Disable     []string `yaml:"disable"`
	EnableStart []string `yaml:"startup"`
	DisableStop []string `yaml:"disableAndStop"`
}

type Runlevels struct {
	Init         []string `yaml:"init"`
	WithPackages []string `yaml:"withPackages"`
	WithServices []string `yaml:"withServices"`
	Final        []string `yaml:"final"`
}

type Config struct {
	Shell    string    `yaml:"shell"`
	Packages []string  `yaml:"packages"`
	Systemd  Services  `yaml:"systemd"`
	OpenRC   Services  `yaml:"openrc"`
	Firewall []string  `yaml:"firewall"`
	IPtables []string  `yaml:"iptables"`
	Execute  Runlevels `yaml:"runlevels"`
}