package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"os"
)

// -------------------------------
// Data structures
// -------------------------------

type Stack struct {
	ID         int       `json:"Id"`
	Name       string    `json:"Name"`
	EndpointId int       `json:"EndpointId"`
	GitConfig  GitConfig `json:"gitConfig"`
}

type GitConfig struct {
	URL            string `json:"url"`
	ReferenceName  string `json:"referenceName"`
	ConfigFilePath string `json:"configFilePath"`
}

type EnvVar struct {
	Name  string `json:"name"`
	Value string `json:"value"`
}

// -------------------------------
// Environment-driven configuration
// -------------------------------

var (
	portainerURL      = os.Getenv("PORTAINER_URL")       // e.g. https://portainer.example.com/api
	portainerToken    = os.Getenv("PORTAINER_TOKEN")     // API access token
	endpointID        = os.Getenv("PORTAINER_ENDPOINT")  // Portainer endpoint ID
	stackName         = os.Getenv("STACK_NAME")          // Name of stack to create/redeploy
	repoURL           = os.Getenv("REPO_URL")            // Git repo URL
	repoRef           = os.Getenv("REPO_REF")            // e.g. refs/heads/main
	repoComposeFile   = os.Getenv("REPO_COMPOSE_FILE")   // e.g. docker-compose.yml
	repoUsername      = os.Getenv("REPO_USERNAME")       // Git username (if needed)
	repoPassword      = os.Getenv("REPO_PASSWORD")       // Git password/token (if needed)
	tlsSkipVerify     = os.Getenv("TLS_SKIP_VERIFY")     // "true" / "false"
)

// -------------------------------
// Helpers
// -------------------------------

func request(client *http.Client, method, url string, body interface{}) (*http.Response, error) {
	var buf io.Reader
	if body != nil {
		data, _ := json.Marshal(body)
		buf = bytes.NewBuffer(data)
	}
	req, err := http.NewRequest(method, url, buf)
	if err != nil {
		return nil, err
	}
	req.Header.Set("Authorization", "Bearer "+portainerToken)
	req.Header.Set("Content-Type", "application/json")
	return client.Do(req)
}

// -------------------------------
// Main logic
// -------------------------------

func main() {
	if portainerURL == "" || portainerToken == "" || endpointID == "" || repoURL == "" || repoRef == "" || repoComposeFile == "" || stackName == "" {
		fmt.Println("Missing required environment variables.")
		os.Exit(1)
	}

	client := &http.Client{}

	// 1. Fetch existing stacks
	resp, err := request(client, "GET", fmt.Sprintf("%s/stacks", portainerURL), nil)
	if err != nil {
		panic(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		fmt.Printf("Error fetching stacks: %s\n", string(body))
		os.Exit(1)
	}

	var stacks []Stack
	if err := json.NewDecoder(resp.Body).Decode(&stacks); err != nil {
		panic(err)
	}

	// 2. Find existing stack from same repo + name
	var existing *Stack
	for _, s := range stacks {
		if s.GitConfig.URL == repoURL && s.Name == stackName {
			existing = &s
			break
		}
	}

	if existing == nil {
		// 3. Create new stack
		payload := map[string]interface{}{
			"composeFile":             repoComposeFile,
			"env":                     []EnvVar{},
			"fromAppTemplate":         false,
			"name":                    stackName,
			"repositoryAuthentication": repoUsername != "" && repoPassword != "",
			"repositoryUsername":      repoUsername,
			"repositoryPassword":      repoPassword,
			"repositoryReferenceName": repoRef,
			"repositoryURL":           repoURL,
			"tlsskipVerify":           tlsSkipVerify == "true",
		}

		url := fmt.Sprintf("%s/stacks/create/standalone/repository?endpointId=%s", portainerURL, endpointID)
		resp, err = request(client, "POST", url, payload)
		if err != nil {
			panic(err)
		}
		defer resp.Body.Close()

		if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated {
			body, _ := io.ReadAll(resp.Body)
			fmt.Printf("Error creating stack: %s\n", string(body))
			os.Exit(1)
		}

		fmt.Printf("✅ Stack %s deployed successfully.\n", stackName)
	} else {
		// 4. Redeploy stack
		payload := map[string]interface{}{
			"env":                        []EnvVar{},
			"prune":                      true,
			"pullImage":                  true,
			"repositoryAuthentication":   repoUsername != "" && repoPassword != "",
			"repositoryAuthorizationType": 0,
			"repositoryUsername":         repoUsername,
			"repositoryPassword":         repoPassword,
			"repositoryReferenceName":    repoRef,
			"stackName":                  stackName,
		}

		url := fmt.Sprintf("%s/stacks/%d/git/redeploy?endpointId=%s", portainerURL, existing.ID, endpointID)
		resp, err = request(client, "PUT", url, payload)
		if err != nil {
			panic(err)
		}
		defer resp.Body.Close()

		if resp.StatusCode != http.StatusOK {
			body, _ := io.ReadAll(resp.Body)
			fmt.Printf("Error redeploying stack: %s\n", string(body))
			os.Exit(1)
		}

		fmt.Printf("♻️ Stack %s redeployed successfully.\n", stackName)
	}
}