package main

import (
	"errors"
	"log"
	"net/http"
	"os"

	"github.com/gin-contrib/cors"
	"github.com/gin-gonic/gin"
	"github.com/glebarez/sqlite"
	"github.com/joho/godotenv"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"

	"log101-blog-services/middleware"
)

var db *gorm.DB

// Emoji counts for each post are retrieved in this format
type PostReaction struct {
	Emoji      string
	TotalCount int
}

// Gorm model
type EmojiReaction struct {
	UserAnonIp string `gorm:"index:idx_anon,unqiue"`
	PostId     string `gorm:"index:idx_anon,unique"`
	Emoji      string
}

// Get the emoji counts foe a given post id
func countEmojis(postId string) (map[string]int, error) {
	postReactions := []PostReaction{}

	// Get the emoji counts for each emoji
	rows := db.Model(&EmojiReaction{}).Where("post_id = ?", postId).Select([]string{"emoji", "COUNT(*) as total_count"}).Group("emoji").Find(&postReactions)
	if rows.Error != nil {
		return nil, errors.New("couldn't get emoji counts")
	}

	// Transform rows to map
	result := make(map[string]int)
	for _, reaction := range postReactions {
		result[reaction.Emoji] = reaction.TotalCount
	}

	return result, nil
}

func main() {
	// Load environment variables
	err := godotenv.Load()
	if err != nil {
		log.Println("Error loading .env file")
	}

	dbPath := os.Getenv("DB_PATH")
	db, err = gorm.Open(sqlite.Open(dbPath), &gorm.Config{})
	if err != nil {
		panic("failed to connect database")
	}

	db.AutoMigrate(&EmojiReaction{})

	r := gin.Default()
	r.LoadHTMLGlob("templates/*")

	// CORS configuration
	corsConfig := cors.DefaultConfig()
	corsConfig.AllowOrigins = []string{"https://log101.dev", "http://blog.log101.local", "https://blog.log101.dev"}

	ginMode := gin.Mode()
	if ginMode == gin.DebugMode {
		corsConfig.AllowOrigins = append(corsConfig.AllowOrigins, "http://localhost:4321")
	}

	corsConfig.AllowHeaders = []string{"hx-current-url", "hx-request", "hx-target", "hx-trigger"}

	// Middlewares
	r.Use(cors.New(corsConfig))
	r.Use(middleware.AnonymizeIPMiddleware())

	blogForm := r.Group("/blog/api/")
	{
		// Get the emoji form, you must provide postId query parameter
		blogForm.GET("/forms/emoji", func(c *gin.Context) {
			postId := c.Query("postId")

			// get emoji counts for each emoji
			emojiCounter, err := countEmojis(postId)
			if err != nil {
				c.HTML(http.StatusOK, "emoji_form.tmpl", gin.H{"error": "error getting the emoji counts"})
				return
			}

			// Return the html template
			c.HTML(http.StatusOK, "emoji_form.tmpl", gin.H{
				"results": emojiCounter,
			})
		})

		// Update the user's reaction to post, this handler will
		// add a new entry to the database with anonymized ip
		// updates if user reacted before
		blogForm.POST("/forms/emoji/post", func(c *gin.Context) {
			reactedPostId := c.PostForm("postId")
			reaction := c.PostForm("emojiInput")

			// Check if parameters are missing
			if reactedPostId == "" || reaction == "" {
				c.HTML(http.StatusOK, "emoji_form.tmpl", gin.H{"error": "missing parameters"})
				return
			}

			// Add the new emoji reaction to the database
			result := db.Clauses(clause.OnConflict{
				DoUpdates: clause.AssignmentColumns([]string{"emoji"}),
			}).Create(&EmojiReaction{UserAnonIp: c.Request.RemoteAddr, Emoji: reaction, PostId: reactedPostId})
			if result.Error != nil {
				c.HTML(http.StatusOK, "emoji_form.tmpl", gin.H{"error": "error writing to database"})
				return
			}

			// get emoji counts for each emoji
			emojiCounter, err := countEmojis(reactedPostId)
			if err != nil {
				c.HTML(http.StatusOK, "emoji_form.tmpl", gin.H{"error": "error getting the emoji counts"})
				return
			}

			// Return the html with the updated emoji counter
			c.HTML(http.StatusOK, "emoji_form.tmpl", gin.H{"results": emojiCounter})
		})
	}

	r.Run(":8000")
}