package main

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strings"
)

type InstanceMetadata struct {
	Version    string                 `json:"Version"`
	ServerName string                 `json:"ServerName"`
	Port       int                    `json:"Port"`
	Config     map[string]interface{} `json:"config"`
}

func PrepareInstanceConfig(templateVersion string, instanceConfigPath string, meta InstanceMetadata, cfg *AppConfig) error {
	return SyncInstanceConfig(templateVersion, instanceConfigPath, meta, cfg)
}

func SyncInstanceConfig(templateVersion string, instanceConfigPath string, meta InstanceMetadata, cfg *AppConfig) error {
	templatePath := filepath.Join(cfg.Storage.ConfigTemplatesDir, templateVersion, "serverconfig.json")

	if err := ensureTemplateExists(templateVersion, templatePath, cfg); err != nil {
		return fmt.Errorf("failed ensuring configuration template availability: %w", err)
	}

	if _, err := os.Stat(instanceConfigPath); os.IsNotExist(err) {
		if err := os.MkdirAll(filepath.Dir(instanceConfigPath), 0755); err != nil {
			return fmt.Errorf("failed creating instance directory tree: %w", err)
		}

		source, err := os.Open(templatePath)
		if err != nil {
			return fmt.Errorf("failed opening baseline template file: %w", err)
		}
		defer source.Close()

		destination, err := os.Create(instanceConfigPath)
		if err != nil {
			return fmt.Errorf("failed creating target instance configuration: %w", err)
		}

		_, err = io.Copy(destination, source)
		destination.Close()
		if err != nil {
			return fmt.Errorf("failed cloning configuration template payload: %w", err)
		}
	}

	data, err := os.ReadFile(instanceConfigPath)
	if err != nil {
		return fmt.Errorf("failed reading configuration data: %w", err)
	}

	var rawConfig map[string]interface{}
	if err := json.Unmarshal(data, &rawConfig); err != nil {
		return fmt.Errorf("failed parsing configuration JSON payload: %w", err)
	}

	for key, value := range meta.Config {
		rawConfig[key] = value
	}

	rawConfig["ServerName"] = meta.ServerName
	rawConfig["Port"] = meta.Port

	instanceDir := filepath.Dir(instanceConfigPath)
	if worldConfig, ok := rawConfig["WorldConfig"].(map[string]interface{}); ok {
		worldConfig["SaveFileLocation"] = filepath.Join(instanceDir, "Saves", "default.vcdbs")
	}

	if modPaths, ok := rawConfig["ModPaths"].([]interface{}); ok {
		for i, pathVal := range modPaths {
			if strPath, ok := pathVal.(string); ok && (strings.Contains(strPath, "/vs-manager/instances/") || filepath.IsAbs(strPath)) && strPath != "Mods" {
				modPaths[i] = filepath.Join(instanceDir, "Mods")
			}
		}
	}

	updatedData, err := json.MarshalIndent(rawConfig, "", "  ")
	if err != nil {
		return fmt.Errorf("failed marshaling updated configuration adjustments: %w", err)
	}

	return os.WriteFile(instanceConfigPath, updatedData, 0644)
}

func ensureTemplateExists(version string, targetPath string, cfg *AppConfig) error {
	if _, err := os.Stat(targetPath); err == nil {
		return nil
	}

	fmt.Printf("Template for version %s not found locally. Fetching remote layout from git server...\n", version)

	if err := os.MkdirAll(filepath.Dir(targetPath), 0755); err != nil {
		return fmt.Errorf("failed to create local template cache directory: %w", err)
	}

	remoteURL := fmt.Sprintf("https://git.bellsworne.tech/chrisbell/vssm_config_templates/raw/branch/main/%s/serverconfig.json", version)

	resp, err := http.Get(remoteURL)
	if err != nil {
		return fmt.Errorf("network error attempting to pull config template: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode == http.StatusNotFound {
		return fmt.Errorf("version template '%s' does not exist in the remote git repository asset tree", version)
	} else if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("remote git mirror returned unexpected HTTP status: %s", resp.Status)
	}

	out, err := os.Create(targetPath)
	if err != nil {
		return fmt.Errorf("failed creating cache file hook on system storage: %w", err)
	}
	defer out.Close()

	_, err = io.Copy(out, resp.Body)
	if err != nil {
		return fmt.Errorf("failed stream-writing network payload cache frame to disk: %w", err)
	}

	fmt.Printf("Successfully cached configuration layout template for version %s\n", version)
	return nil
}