package main

import (
	"crypto/hmac"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"sync"
	"time"
)

const (
	domainsDir = "/docker/web-hosts/domains"
	logsDir    = "/docker/web-hosts/logs"
)

var (
	deployMutex  sync.Mutex
	lastDeploys  = make(map[string]time.Time)
	domainConfig = make(map[string]DomainConfig)
)

type DomainConfig struct {
	Secret       string
	TargetBranch string
	DeployScript string
}

type GiteaPayload struct {
	Ref        string `json:"ref"`
	Repository struct {
		Name     string `json:"name"`
		FullName string `json:"full_name"`
	} `json:"repository"`
	Pusher struct {
		Username string `json:"username"`
	} `json:"pusher"`
}

func loadConfig() {
	// Load domain configurations from environment
	// Format: WEBHOOK_<DOMAIN_UNDERSCORE>_SECRET, WEBHOOK_<DOMAIN_UNDERSCORE>_BRANCH
	// e.g., WEBHOOK_TEST_COPPERTONE_TECH_SECRET

	domains := []string{
		"test.coppertone.tech",
		"chuckie.coppertone.tech",
		"dev.coppertone.tech",
		"games.coppertone.tech",
		"coppertone.tech",
	}

	globalSecret := os.Getenv("WEBHOOK_SECRET")

	for _, domain := range domains {
		envKey := strings.ReplaceAll(strings.ReplaceAll(domain, ".", "_"), "-", "_")
		envKey = strings.ToUpper(envKey)

		secret := os.Getenv("WEBHOOK_" + envKey + "_SECRET")
		if secret == "" {
			secret = globalSecret
		}

		branch := os.Getenv("WEBHOOK_" + envKey + "_BRANCH")
		if branch == "" {
			branch = "main"
		}

		deployScript := filepath.Join(domainsDir, domain, "deploy.sh")
		if _, err := os.Stat(deployScript); os.IsNotExist(err) {
			altDeploy := filepath.Join(domainsDir, domain, "scripts", "deploy.sh")
			if _, altErr := os.Stat(altDeploy); altErr == nil {
				deployScript = altDeploy
			}
		}

		domainConfig[domain] = DomainConfig{
			Secret:       secret,
			TargetBranch: branch,
			DeployScript: deployScript,
		}

		log.Printf("Configured domain: %s (branch: %s, secret: %v)", domain, branch, secret != "")
	}
}

func main() {
	port := os.Getenv("WEBHOOK_PORT")
	if port == "" {
		port = "9090"
	}

	loadConfig()

	http.HandleFunc("/health", healthHandler)
	http.HandleFunc("/deploy/", deployHandler)
	http.HandleFunc("/", rootHandler)

	log.Printf("Webhook service listening on :%s", port)
	log.Fatal(http.ListenAndServe("127.0.0.1:"+port, nil))
}

func rootHandler(w http.ResponseWriter, r *http.Request) {
	log.Printf("[REQUEST] %s %s from %s", r.Method, r.URL.Path, r.RemoteAddr)

	if r.URL.Path == "/" {
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"service": "web-hosts-webhook",
			"status":  "running",
			"domains": getDomainList(),
		})
		return
	}

	http.NotFound(w, r)
}

func healthHandler(w http.ResponseWriter, r *http.Request) {
	w.Write([]byte("OK"))
}

func deployHandler(w http.ResponseWriter, r *http.Request) {
	// Extract domain from path: /deploy/<domain>
	path := strings.TrimPrefix(r.URL.Path, "/deploy/")
	domain := strings.TrimSuffix(path, "/")

	log.Printf("[DEPLOY] Request for domain: %s from %s", domain, r.RemoteAddr)
	log.Printf("[HEADERS] %v", r.Header)

	config, exists := domainConfig[domain]
	if !exists {
		log.Printf("[ERROR] Unknown domain: %s", domain)
		http.Error(w, "Unknown domain", http.StatusNotFound)
		return
	}

	// Check deploy script exists
	if _, err := os.Stat(config.DeployScript); os.IsNotExist(err) {
		log.Printf("[ERROR] Deploy script not found: %s", config.DeployScript)
		http.Error(w, "Deploy script not found", http.StatusNotFound)
		return
	}

	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	body, err := io.ReadAll(r.Body)
	if err != nil {
		log.Printf("[ERROR] Failed to read body: %v", err)
		http.Error(w, "Failed to read body", http.StatusBadRequest)
		return
	}

	log.Printf("[PAYLOAD] %s", string(body))

	// Verify signature if secret is configured
	if config.Secret != "" {
		sig := r.Header.Get("X-Gitea-Signature")
		if sig == "" {
			sig = r.Header.Get("X-Hub-Signature-256")
			if sig != "" {
				sig = strings.TrimPrefix(sig, "sha256=")
			}
		}
		if !verifySignature(body, sig, config.Secret) {
			log.Printf("[REJECTED] Invalid signature for %s", domain)
			http.Error(w, "Invalid signature", http.StatusUnauthorized)
			return
		}
	}

	// Parse payload
	var payload GiteaPayload
	if len(body) > 0 {
		if err := json.Unmarshal(body, &payload); err != nil {
			log.Printf("[WARN] Failed to parse payload: %v", err)
		}
	}

	// Check branch
	force := r.URL.Query().Get("force") == "true"
	expectedRef := "refs/heads/" + config.TargetBranch
	if payload.Ref != "" && payload.Ref != expectedRef && !force {
		log.Printf("[SKIP] Branch %s != %s for %s", payload.Ref, expectedRef, domain)
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]string{
			"status":  "skipped",
			"message": fmt.Sprintf("Not %s branch", config.TargetBranch),
		})
		return
	}

	// Rate limit per domain
	deployMutex.Lock()
	if last, ok := lastDeploys[domain]; ok && time.Since(last) < 30*time.Second {
		deployMutex.Unlock()
		log.Printf("[RATE_LIMITED] %s - last deploy %v ago", domain, time.Since(last))
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]string{
			"status":  "rate_limited",
			"message": "Please wait before deploying again",
		})
		return
	}
	lastDeploys[domain] = time.Now()
	deployMutex.Unlock()

	log.Printf("[DEPLOY] Triggering deploy for %s (repo: %s, pusher: %s)",
		domain, payload.Repository.FullName, payload.Pusher.Username)

	// Run deploy in background
	go runDeploy(domain, config)

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]string{
		"status":  "success",
		"message": fmt.Sprintf("Deployment triggered for %s", domain),
	})
}

func runDeploy(domain string, config DomainConfig) {
	logFile := filepath.Join(logsDir, domain+"-webhook.log")

	cmd := exec.Command(config.DeployScript)
	cmd.Dir = filepath.Dir(config.DeployScript)

	output, err := cmd.CombinedOutput()
	if err != nil {
		log.Printf("[DEPLOY_FAILED] %s: %v\n%s", domain, err, output)
	} else {
		log.Printf("[DEPLOY_SUCCESS] %s:\n%s", domain, output)
	}

	// Append to log file
	f, _ := os.OpenFile(logFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if f != nil {
		fmt.Fprintf(f, "\n=== Deploy %s ===\n%s\n", time.Now().Format(time.RFC3339), output)
		f.Close()
	}
}

func verifySignature(payload []byte, signature, secret string) bool {
	if signature == "" {
		return false
	}
	mac := hmac.New(sha256.New, []byte(secret))
	mac.Write(payload)
	expected := hex.EncodeToString(mac.Sum(nil))
	return hmac.Equal([]byte(expected), []byte(signature))
}

func getDomainList() []string {
	domains := make([]string, 0, len(domainConfig))
	for d := range domainConfig {
		domains = append(domains, d)
	}
	return domains
}