package main

import (
	"context"
	"database/sql"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"strings"
	"time"

	"ddns-manager/db"
	"ddns-manager/templates"

	"github.com/cloudflare/cloudflare-go"
	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
	_ "github.com/mattn/go-sqlite3" // SQLite driver
	"github.com/robfig/cron/v3"
)

type DNSRecord struct {
	ID        string `json:"id"`
	Type      string `json:"type"`
	Name      string `json:"name"`
	Content   string `json:"content"`
	TTL       int    `json:"ttl"`
	Proxied   bool   `json:"proxied"`
	CreatedOn string `json:"created_on"`
}

type UpdateFrequency struct {
	Label string `json:"label"`
	Value string `json:"value"`
}

type ErrorResponse struct {
	Error string `json:"error"`
}

var (
	api       *cloudflare.API
	scheduler *cron.Cron
	lastIP    string
	jobID     cron.EntryID
	queries   *db.Queries
)

func initDatabase() (*sql.DB, error) {
	dbPath := os.Getenv("DB_PATH")
	if dbPath == "" {
		dbPath = "./ddns.db"
	}

	log.Printf("Using database path: %s", dbPath)

	sqlDB, err := sql.Open("sqlite3", dbPath)
	if err != nil {
		return nil, fmt.Errorf("failed to open database: %w", err)
	}

	if err := db.InitSchema(sqlDB); err != nil {
		return nil, fmt.Errorf("failed to initialize schema: %w", err)
	}

	queries = db.New(sqlDB)

	return sqlDB, nil
}

func initCloudflare(apiToken, zoneID string) error {
	if apiToken == "" || zoneID == "" {
		return nil
	}

	var err error
	api, err = cloudflare.NewWithAPIToken(apiToken)
	if err != nil {
		return fmt.Errorf("failed to initialize Cloudflare API: %w", err)
	}

	return nil
}

func getCurrentIP() (string, error) {
	resp, err := http.Get("https://api.ipify.org")
	if err != nil {
		return "", fmt.Errorf("failed to get current IP: %w", err)
	}
	defer resp.Body.Close()

	ip, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", fmt.Errorf("failed to read IP response: %w", err)
	}

	return string(ip), nil
}

func getDNSRecords(zoneID string) ([]DNSRecord, error) {
	if api == nil {
		return nil, fmt.Errorf("cloudflare API not initialized")
	}

	ctx := context.Background()
	rc := cloudflare.ZoneIdentifier(zoneID)

	recs, _, err := api.ListDNSRecords(ctx, rc, cloudflare.ListDNSRecordsParams{})
	if err != nil {
		return nil, fmt.Errorf("failed to get DNS records: %w", err)
	}

	var records []DNSRecord
	for _, rec := range recs {
		records = append(records, DNSRecord{
			ID:        rec.ID,
			Type:      rec.Type,
			Name:      rec.Name,
			Content:   rec.Content,
			TTL:       rec.TTL,
			Proxied:   *rec.Proxied,
			CreatedOn: rec.CreatedOn.Format(time.RFC3339),
		})
	}

	return records, nil
}

func createDNSRecord(zoneID, domain, name, recordType, content string, ttl int, proxied bool) error {
	if api == nil {
		return fmt.Errorf("cloudflare API not initialized")
	}

	if !strings.HasSuffix(name, domain) && name != "@" {
		name = name + "." + domain
	}

	if name == "@" {
		name = domain
	}

	ctx := context.Background()
	rc := cloudflare.ZoneIdentifier(zoneID)

	_, err := api.CreateDNSRecord(ctx, rc, cloudflare.CreateDNSRecordParams{
		Type:    recordType,
		Name:    name,
		Content: content,
		TTL:     ttl,
		Proxied: &proxied,
	})
	if err != nil {
		return fmt.Errorf("failed to create DNS record: %w", err)
	}

	return nil
}

func updateDNSRecord(zoneID, id, name, recordType, content string, ttl int, proxied bool) error {
	if api == nil {
		return fmt.Errorf("cloudflare API not initialized")
	}

	ctx := context.Background()
	rc := cloudflare.ZoneIdentifier(zoneID)

	_, err := api.UpdateDNSRecord(ctx, rc, cloudflare.UpdateDNSRecordParams{
		ID:      id,
		Type:    recordType,
		Name:    name,
		Content: content,
		TTL:     ttl,
		Proxied: &proxied,
	})
	if err != nil {
		return fmt.Errorf("failed to update DNS record: %w", err)
	}

	return nil
}

func deleteDNSRecord(zoneID, id string) error {
	if api == nil {
		return fmt.Errorf("cloudflare API not initialized")
	}

	ctx := context.Background()
	rc := cloudflare.ZoneIdentifier(zoneID)

	err := api.DeleteDNSRecord(ctx, rc, id)
	if err != nil {
		return fmt.Errorf("failed to delete DNS record: %w", err)
	}

	return nil
}

func updateAllRecordsWithCurrentIP(zoneID string) error {
	if api == nil {
		return fmt.Errorf("cloudflare API not initialized")
	}

	currentIP, err := getCurrentIP()
	if err != nil {
		return err
	}

	if currentIP == lastIP {
		log.Println("IP hasn't changed, no updates needed")
		return nil
	}

	lastIP = currentIP

	ctx := context.Background()
	rc := cloudflare.ZoneIdentifier(zoneID)

	records, _, err := api.ListDNSRecords(ctx, rc, cloudflare.ListDNSRecordsParams{
		Type: "A",
	})
	if err != nil {
		return fmt.Errorf("failed to get DNS records: %w", err)
	}

	for _, rec := range records {
		if rec.Content != currentIP {
			proxied := rec.Proxied
			_, err := api.UpdateDNSRecord(ctx, rc, cloudflare.UpdateDNSRecordParams{
				ID:      rec.ID,
				Type:    rec.Type,
				Name:    rec.Name,
				Content: currentIP,
				TTL:     rec.TTL,
				Proxied: proxied,
			})
			if err != nil {
				log.Printf("Failed to update record %s: %v", rec.Name, err)
			} else {
				log.Printf("Updated record %s to %s", rec.Name, currentIP)
			}
		}
	}

	return nil
}

func scheduleUpdates(zoneID, updatePeriod string) error {
	if jobID != 0 {
		scheduler.Remove(jobID)
	}

	if updatePeriod == "" {
		log.Println("Automatic updates disabled")
		return nil
	}

	var err error
	jobID, err = scheduler.AddFunc(updatePeriod, func() {
		log.Println("Running scheduled IP update")
		if err := updateAllRecordsWithCurrentIP(zoneID); err != nil {
			log.Printf("Scheduled update failed: %v", err)
		}
	})
	if err != nil {
		return fmt.Errorf("failed to schedule updates: %w", err)
	}

	log.Printf("Scheduled IP updates with cron: %s", updatePeriod)
	return nil
}

func main() {
	sqlDB, err := initDatabase()
	if err != nil {
		log.Fatalf("Failed to initialize database: %v", err)
	}
	defer sqlDB.Close()

	config, err := queries.GetConfig(context.Background())
	if err != nil {
		log.Printf("Warning: Failed to load configuration: %v", err)
		config = db.Config{
			Domain:       "mz.uy",
			UpdatePeriod: "0 */6 * * *",
		}
	}

	if err := initCloudflare(config.ApiToken, config.ZoneID); err != nil {
		log.Printf("Warning: Cloudflare initialization failed: %v", err)
	}

	scheduler = cron.New()
	scheduler.Start()
	defer scheduler.Stop()

	if config.ApiToken != "" && config.ZoneID != "" && config.UpdatePeriod != "" {
		if err := scheduleUpdates(config.ZoneID, config.UpdatePeriod); err != nil {
			log.Printf("Warning: Failed to schedule updates: %v", err)
		}
	}

	e := echo.New()
	e.Use(middleware.Logger())
	e.Use(middleware.Recover())
	e.Static("/assets", "assets")

	apiGroup := e.Group("/api")
	{
		apiGroup.GET("/config", func(c echo.Context) error {
			configStatus := struct {
				IsConfigured bool   `json:"is_configured"`
				ZoneID       string `json:"zone_id"`
				Domain       string `json:"domain"`
				UpdatePeriod string `json:"update_period"`
			}{
				IsConfigured: config.ApiToken != "" && config.ZoneID != "",
				ZoneID:       config.ZoneID,
				Domain:       config.Domain,
				UpdatePeriod: config.UpdatePeriod,
			}
			return c.JSON(http.StatusOK, configStatus)
		})

		apiGroup.POST("/config", func(c echo.Context) error {
			var newConfig struct {
				APIToken     string `json:"api_token"`
				ZoneID       string `json:"zone_id"`
				Domain       string `json:"domain"`
				UpdatePeriod string `json:"update_period"`
			}

			if err := c.Bind(&newConfig); err != nil {
				return c.JSON(http.StatusBadRequest, ErrorResponse{Error: "Invalid request"})
			}

			err := queries.UpsertConfig(context.Background(), db.UpsertConfigParams{
				ApiToken:     newConfig.APIToken,
				ZoneID:       newConfig.ZoneID,
				Domain:       newConfig.Domain,
				UpdatePeriod: newConfig.UpdatePeriod,
			})
			if err != nil {
				return c.JSON(http.StatusInternalServerError, ErrorResponse{Error: fmt.Sprintf("Failed to save configuration: %v", err)})
			}

			config.ApiToken = newConfig.APIToken
			config.ZoneID = newConfig.ZoneID
			config.Domain = newConfig.Domain
			config.UpdatePeriod = newConfig.UpdatePeriod

			if err := initCloudflare(config.ApiToken, config.ZoneID); err != nil {
				return c.JSON(http.StatusInternalServerError, ErrorResponse{Error: fmt.Sprintf("Failed to initialize Cloudflare client: %v", err)})
			}

			if err := scheduleUpdates(config.ZoneID, config.UpdatePeriod); err != nil {
				return c.JSON(http.StatusInternalServerError, ErrorResponse{Error: fmt.Sprintf("Failed to schedule updates: %v", err)})
			}

			return c.JSON(http.StatusOK, map[string]string{"message": "Configuration updated successfully"})
		})

		apiGroup.GET("/update-frequencies", func(c echo.Context) error {
			frequencies := []UpdateFrequency{
				{Label: "Every 1 minutes", Value: "*/1 * * * *"},
				{Label: "Every 5 minutes", Value: "*/5 * * * *"},
				{Label: "Every 30 minutes", Value: "*/30 * * * *"},
				{Label: "Hourly", Value: "0 * * * *"},
				{Label: "Every 6 hours", Value: "0 */6 * * *"},
				{Label: "Daily", Value: "0 0 * * *"},
				{Label: "Never (manual only)", Value: ""},
			}
			return c.JSON(http.StatusOK, frequencies)
		})

		apiGroup.GET("/current-ip", func(c echo.Context) error {
			ip, err := getCurrentIP()
			if err != nil {
				return c.JSON(http.StatusInternalServerError, ErrorResponse{Error: fmt.Sprintf("Failed to get current IP: %v", err)})
			}
			return c.JSON(http.StatusOK, map[string]string{"ip": ip})
		})

		apiGroup.GET("/records", func(c echo.Context) error {
			if config.ApiToken == "" || config.ZoneID == "" {
				return c.JSON(http.StatusBadRequest, ErrorResponse{Error: "API not configured"})
			}

			records, err := getDNSRecords(config.ZoneID)
			if err != nil {
				return c.JSON(http.StatusInternalServerError, ErrorResponse{Error: fmt.Sprintf("Failed to get DNS records: %v", err)})
			}
			return c.JSON(http.StatusOK, records)
		})

		apiGroup.POST("/records", func(c echo.Context) error {
			if config.ApiToken == "" || config.ZoneID == "" {
				return c.JSON(http.StatusBadRequest, ErrorResponse{Error: "API not configured"})
			}

			var record struct {
				Name    string `json:"name"`
				Type    string `json:"type"`
				Content string `json:"content"`
				TTL     int    `json:"ttl"`
				Proxied bool   `json:"proxied"`
				UseMyIP bool   `json:"use_my_ip"`
			}

			if err := c.Bind(&record); err != nil {
				return c.JSON(http.StatusBadRequest, ErrorResponse{Error: "Invalid request"})
			}

			if record.UseMyIP {
				ip, err := getCurrentIP()
				if err != nil {
					return c.JSON(http.StatusInternalServerError, ErrorResponse{Error: fmt.Sprintf("Failed to get current IP: %v", err)})
				}
				record.Content = ip
			}

			if err := createDNSRecord(config.ZoneID, config.Domain, record.Name, record.Type, record.Content, record.TTL, record.Proxied); err != nil {
				return c.JSON(http.StatusInternalServerError, ErrorResponse{Error: fmt.Sprintf("Failed to create DNS record: %v", err)})
			}

			return c.JSON(http.StatusOK, map[string]string{"message": "DNS record created successfully"})
		})

		apiGroup.PUT("/records/:id", func(c echo.Context) error {
			if config.ApiToken == "" || config.ZoneID == "" {
				return c.JSON(http.StatusBadRequest, ErrorResponse{Error: "API not configured"})
			}

			id := c.Param("id")
			var record struct {
				Name    string `json:"name"`
				Type    string `json:"type"`
				Content string `json:"content"`
				TTL     int    `json:"ttl"`
				Proxied bool   `json:"proxied"`
				UseMyIP bool   `json:"use_my_ip"`
			}

			if err := c.Bind(&record); err != nil {
				return c.JSON(http.StatusBadRequest, ErrorResponse{Error: "Invalid request"})
			}

			if record.UseMyIP {
				ip, err := getCurrentIP()
				if err != nil {
					return c.JSON(http.StatusInternalServerError, ErrorResponse{Error: fmt.Sprintf("Failed to get current IP: %v", err)})
				}
				record.Content = ip
			}

			if err := updateDNSRecord(config.ZoneID, id, record.Name, record.Type, record.Content, record.TTL, record.Proxied); err != nil {
				return c.JSON(http.StatusInternalServerError, ErrorResponse{Error: fmt.Sprintf("Failed to update DNS record: %v", err)})
			}

			return c.JSON(http.StatusOK, map[string]string{"message": "DNS record updated successfully"})
		})

		apiGroup.DELETE("/records/:id", func(c echo.Context) error {
			if config.ApiToken == "" || config.ZoneID == "" {
				return c.JSON(http.StatusBadRequest, ErrorResponse{Error: "API not configured"})
			}

			id := c.Param("id")
			if err := deleteDNSRecord(config.ZoneID, id); err != nil {
				return c.JSON(http.StatusInternalServerError, ErrorResponse{Error: fmt.Sprintf("Failed to delete DNS record: %v", err)})
			}

			return c.JSON(http.StatusOK, map[string]string{"message": "DNS record deleted successfully"})
		})

		apiGroup.POST("/update-all", func(c echo.Context) error {
			if config.ApiToken == "" || config.ZoneID == "" {
				return c.JSON(http.StatusBadRequest, ErrorResponse{Error: "API not configured"})
			}

			if err := updateAllRecordsWithCurrentIP(config.ZoneID); err != nil {
				return c.JSON(http.StatusInternalServerError, ErrorResponse{Error: fmt.Sprintf("Failed to update records: %v", err)})
			}

			return c.JSON(http.StatusOK, map[string]string{"message": "All A records updated with current IP"})
		})
	}

	e.GET("/", func(c echo.Context) error {
		component := templates.Index(templates.IndexProps{
			Title: "mz.uy DNS Manager",
		})
		return templates.Render(c.Response(), component)
	})

	log.Println("Starting server on http://localhost:3000")
	log.Fatal(e.Start(":3000"))
}