package main

import (
	"fmt"
	"os"
	"os/exec"
	"path"
	"strings"
	"text/template"

	"github.com/hjson/hjson-go/v4"
	"github.com/ghodss/yaml"
	"dario.cat/mergo"
)

type Config struct {
	System		SystemConfig
	Networking	NetworkingConfig
	Services	map[string]ServiceConfig
}

type SystemConfig struct {
	Base		string
	Packages	[]string
}

type NetworkingConfig struct {
}

type ServiceConfig struct {
	Enable		string

	Config		map[string]interface{}
	ExtraConfig	string

	Src		string
	Ports		[]string
	Volumes		[]string

	Provider	string
	Packages	[]string
	ConfigFiles	[]string
}

func main() {
	var err error
	var config Config
	var systemConfig Config

	// Read user config file
	file, err := os.ReadFile("goolinux.json")
	if err != nil {
		fmt.Println("Cannot read user config file")
		fmt.Println(err)
		return
	}

	err = hjson.Unmarshal(file, &config)
	if err != nil {
		fmt.Println(err)
		return
	}

	// Read system "base" config file if it exists
	if config.System.Base != "" {
		path := "services/" + config.System.Base + ".json"
		file, err = os.ReadFile(path)
		if err != nil {
			fmt.Println("Cannot read system base config file")
			fmt.Println(err)
			return
		}

		err = hjson.Unmarshal(file, &systemConfig)
		if err != nil {
			fmt.Println(err)
			return
		}

		// Merge base system config layer
		mergo.Merge(&config, systemConfig, mergo.WithOverride)
	}

	// Parse services
	for name, service := range config.Services {
		var b strings.Builder
		var s ServiceConfig
		fmt.Printf("Service: %s\n", name)

		// Read service config file
		if service.Provider == "" { service.Provider = "system" }
		fmt.Fprintf(&b, "services/%s/%s.json", name, service.Provider)
		c, err := os.ReadFile(b.String())
		if err != nil {
			fmt.Println("Unknown service: ", err)
			return
		}

		// Parse service config
		err = hjson.Unmarshal(c, &s)
		if err != nil {
			fmt.Println("Error parsing config file")
			fmt.Println(err)
			return
		}
		mergo.Merge(&s, service, mergo.WithOverride)
		config.Services[name] = s

		fmt.Printf(" %v\n", s)

		// Add service packages to the global list
		config.System.Packages = append(config.System.Packages, s.Packages...)

		// Generate a config file
		for _, f := range s.ConfigFiles {
			var b strings.Builder
			f := strings.Split(f, ":")

			// Read service template file
			fmt.Fprintf(&b, "services/%s/%s", name, f[0])
			t, err := os.ReadFile(b.String())
			if err != nil {
				fmt.Println("No template for service: ", err)
				return
			}

			tmpl, err := template.New(name).Parse(string(t))
			if err != nil {
				fmt.Println("Error reading template")
				fmt.Println(err)
				return
			}

			err = os.MkdirAll("/config" + path.Dir(f[1]), 0555)
			if err != nil {
				fmt.Println("Error creating config directory.")
				fmt.Println(err)
				return
			}

			fd, err := os.Create("/config" + f[1])
			defer fd.Close()
			if err != nil {
				fmt.Println(err)
				fmt.Println("No permission to create config file")
				return
			}
			fd.Chmod(0444)

			err = tmpl.Execute(fd, s)
			if err != nil {
				fmt.Println(err)
				return
			}
		}
	}

	// Convert service configs from JSON to YAML
	fmt.Println("Converting docker service configs to YAML")
	servicesPath := "/config/services/docker/"
	dirents, err := os.ReadDir(servicesPath)
	for _, d := range dirents {
		if d.IsDir() == true { continue }
		if strings.HasSuffix(d.Name(), ".json") != true { continue }
		f := servicesPath + d.Name()

		j, err := os.ReadFile(f)
		if err != nil {
			fmt.Println(err)
			return
		}

		y, err := yaml.JSONToYAML(j)
		if err != nil {
			fmt.Println(err)
			return
		}

		fd, _ := os.Create(strings.TrimSuffix(f, ".json") + ".yaml")
		defer fd.Close()
		fd.Chmod(0444)
		fd.Write(y)
	}

	// Parse package list

	// Add extra packages needed
	// ...

	// Install packages
	fmt.Println("Installing packages")
	var installString = []string{"add", "--no-interactive", "--no-progress"}
	var testArgs, args []string
	var out []byte
	testArgs = append(installString, "-s")
	testArgs = append(testArgs, config.System.Packages...)
	out, err = exec.Command("/sbin/apk", testArgs...).CombinedOutput()
	if err != nil {
		fmt.Println("===")
		fmt.Println(err)
		fmt.Println(string(out))
		fmt.Println("===")
		fmt.Println("Error preparing packages")
		return
	}

	args = append(installString, config.System.Packages...)
	out, err = exec.Command("/sbin/apk", args...).CombinedOutput()
	if err != nil {
		fmt.Println("===")
		fmt.Println(err)
		fmt.Println(string(out))
		fmt.Println("===")
		fmt.Println("Error installing packages")
		return
	}

	// (Re)start services

	// Handle docker services
	fmt.Println("Starting docker services")
	servicesPath = "/config/services/docker/"
	dirents, err = os.ReadDir(servicesPath)
	for _, d := range dirents {
		if d.IsDir() == true { continue }
		if strings.HasSuffix(d.Name(), ".yaml") != true { continue }
		f := servicesPath + d.Name()

		fmt.Println(" Starting:", d.Name())
		var cmd = "/usr/bin/podman-compose"
		var args = []string{"-f", f, "up", "-d"}
		out, err := exec.Command(cmd, args...).CombinedOutput()
		if err != nil {
			fmt.Println("===")
			fmt.Println(err)
			fmt.Println(string(out))
			fmt.Println("===")
			fmt.Println("Error starting service:" + d.Name())
			return
		}
	}
}