package app

import (
	"errors"
	"log/slog"
	"time"

	"github.com/gin-gonic/gin"

	"galo/internal/auth"
	"galo/internal/httpx"
	"galo/internal/logging"
)

const ctxRequestID = "logging.request_id"

// requestIDMiddleware assigns a request identifier, echoes it in the response
// header and stores it in the request context for downstream logging.
func requestIDMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		id := c.GetHeader("X-Request-ID")
		if !logging.ValidRequestID(id) {
			id = logging.NewRequestID()
		}
		c.Set(ctxRequestID, id)
		c.Header("X-Request-ID", id)
		c.Request = c.Request.WithContext(logging.WithRequestID(c.Request.Context(), id))
		c.Next()
	}
}

// accessLogMiddleware writes one debug-level line per completed request and
// logs collected errors. The query string, Authorization header and bodies are
// never logged.
func accessLogMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		start := time.Now()
		c.Next()

		if route := c.FullPath(); shouldLogAccess(route) {
			logRequest(c, start, route)
		}
		logErrors(c)
	}
}

func shouldLogAccess(route string) bool {
	return route != "" && route != "/api/health"
}

func logRequest(c *gin.Context, start time.Time, route string) {
	slog.Default().LogAttrs(c.Request.Context(), slog.LevelDebug, "http request",
		slog.String("method", c.Request.Method),
		slog.String("route", route),
		slog.Int("status", c.Writer.Status()),
		slog.Duration("latency", time.Since(start)),
		slog.Int("bytes", c.Writer.Size()),
		slog.String("client_ip", c.ClientIP()),
		slog.String("user_id", auth.UserID(c)),
		slog.String("request_id", logging.RequestID(c.Request.Context())),
	)
}

func logErrors(c *gin.Context) {
	for _, ginErr := range c.Errors {
		level := slog.LevelError
		var appErr *httpx.AppError
		if errors.As(ginErr.Err, &appErr) && appErr.Status < 500 {
			level = slog.LevelDebug
		}
		slog.Default().LogAttrs(c.Request.Context(), level, "request error",
			slog.String("error", ginErr.Err.Error()),
			slog.String("route", c.FullPath()),
			slog.String("request_id", logging.RequestID(c.Request.Context())),
		)
	}
}