package router

import (
	"fmt"
	"log/slog"
	"net/http"
	"runtime/debug"
	"strings"
	"time"
)

import (
	"github.com/gin-gonic/gin"
)

import (
	"auth-server/common"
	"auth-server/logger"
)

func InitMiddleware(r *gin.Engine) {
	// NoCache is a middleware function that appends headers
	r.Use(NoCache)
	// 跨域处理
	r.Use(Options)
	// Secure is a middleware function that appends security
	r.Use(Secure)
	// Use Slog Logger
	r.Use(GinLogger(logger.WithGroup("gin")))
	// Global Recover
	r.Use(GinRecovery(logger.WithGroup("ginRecovery")))
	// check header
	r.Use(CheckLanguage)
	r.Use(CheckSource)
	r.Use(CheckProduct)
	// check token
	r.Use(CheckAuth)
}

// NoCache is a middleware function that appends headers
// to prevent the client from caching the HTTP response.
func NoCache(c *gin.Context) {
	c.Header("Cache-Control", "no-cache, no-store, max-age=0, must-revalidate, value")
	c.Header("Expires", "Thu, 01 Jan 1970 00:00:00 GMT")
	c.Header("Last-Modified", time.Now().UTC().Format(http.TimeFormat))
	c.Next()
}

// Options is a middleware function that appends headers
// for options requests and aborts then exits the middleware
// chain and ends the request.
func Options(c *gin.Context) {
	if c.Request.Method != "OPTIONS" {
		c.Next()
	} else {
		c.Header("Access-Control-Allow-Origin", "*")
		c.Header("Access-Control-Allow-Methods", "GET,POST,PUT,PATCH,DELETE,OPTIONS")
		c.Header("Access-Control-Allow-Headers", "authorization, origin, content-type, accept")
		c.Header("Allow", "HEAD,GET,POST,PUT,PATCH,DELETE,OPTIONS")
		c.Header("Content-Type", "application/json")
		c.AbortWithStatus(200)
	}
}

// Secure is a middleware function that appends security
// and resource access headers.
func Secure(c *gin.Context) {
	c.Header("Access-Control-Allow-Origin", "*")
	//c.Header("X-Frame-Options", "DENY")
	c.Header("X-Content-Type-Options", "nosniff")
	c.Header("X-XSS-Protection", "1; mode=block")
	if c.Request.TLS != nil {
		c.Header("Strict-Transport-Security", "max-age=31536000")
	}

	// Also consider adding Content-Security-Policy headers
	// c.Header("Content-Security-Policy", "script-src 'self' https://cdnjs.cloudflare.com")
}

func CheckLanguage(c *gin.Context) {
	if strings.Contains(c.FullPath(), "/api/v1/auth") {
		ok := false
		language := c.Request.Header.Get("Language")
		for _, l := range common.MetadataConfig.GetLanguages() {
			if language == l.ToString() {
				ok = true
			}
		}
		if !ok {
			c.AbortWithStatusJSON(200, common.ErrToH(common.InvalidLanguage, c.GetHeader("Language")))
		} else {
			c.Set("language", language)
		}
	}
	c.Next()
}

func CheckSource(c *gin.Context) {
	if strings.Contains(c.FullPath(), "/api/v1/auth") {
		source := c.Request.Header.Get("Source")
		ok := false
		for _, s := range common.MetadataConfig.GetSources() {
			if source == s.ToString() {
				ok = true
			}
		}
		if !ok {
			c.AbortWithStatusJSON(200, common.ErrToH(common.InvalidSource, c.GetHeader("Source")))
		} else {
			c.Set("source", source)
		}
	}
	c.Next()
}

func CheckProduct(c *gin.Context) {
	if strings.Contains(c.FullPath(), "/api/v1/auth") {
		product := c.Request.Header.Get("Product")
		if strings.ToUpper(product) != common.MetadataConfig.GetProduct().ToString() {
			c.AbortWithStatusJSON(200, common.ErrToH(common.InvalidProduct, product))
		} else {
			c.Set("product", product)
		}
	}
	c.Next()
}

func CheckAuth(c *gin.Context) {
	if strings.Contains(c.FullPath(), "/api/v1/auth") {
		token := c.Request.Header.Get("Authorization")
		uid, username, err := common.ParseToken(strings.TrimPrefix(token, "Bearer "))
		if err != nil {
			c.AbortWithStatusJSON(200, common.ErrToH(common.InvalidToken, c.GetHeader("locale")))
		}
		c.Set("uid", uid)
		c.Set("username", username)
	}
	c.Next()
}

func GinLogger(logger *slog.Logger) gin.HandlerFunc {
	return func(c *gin.Context) {
		start := time.Now()
		path := c.Request.URL.Path
		if len(c.Request.URL.RawQuery) > 0 {
			path += "?" + c.Request.URL.RawQuery
		}
		c.Next()

		cost := time.Since(start)
		logger.Info(fmt.Sprintf("[%s]%s, header[%s-%s-%s] ip[%s], resp[%d] %s errors[%s]",
			c.Request.Method,
			path,
			c.GetHeader("Product"),
			c.GetHeader("Source"),
			c.GetHeader("Language"),
			c.ClientIP(),
			c.Writer.Status(),
			cost.String(),
			c.Errors.ByType(gin.ErrorTypePrivate).String(),
		))
	}
}

func GinRecovery(logger *slog.Logger) gin.HandlerFunc {
	return gin.CustomRecovery(func(c *gin.Context, recovered interface{}) {
		logger.Error("Recovery from panic", "recoverd", recovered, "stack", string(debug.Stack()))
		common.HttpErr(c, common.Unknown)
		c.AbortWithStatus(http.StatusOK)
	})
}