// Package gin adapts Gin to GoOmni's transport-neutral router contract.
// Business packages should import httpx and app, not this package.
package gin

import (
	"net/http"

	"git.yuntuo.hk/k2safe/go-omni/httpx"
	ginlib "github.com/gin-gonic/gin"
)

// Router is the default Gin-backed GoOmni router.
type Router struct {
	engine *ginlib.Engine
}

// New creates a Gin router without Gin's default logger or recovery middleware.
func New(mode string) *Router {
	if mode != "" {
		ginlib.SetMode(mode)
	}
	return &Router{engine: ginlib.New()}
}

// NewWithEngine wraps an existing Gin engine for incremental migration.
func NewWithEngine(engine *ginlib.Engine) *Router { return &Router{engine: engine} }

// Engine exposes the underlying Gin engine to adapter-specific integrations.
func (r *Router) Engine() *ginlib.Engine { return r.engine }

func (r *Router) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
	r.engine.ServeHTTP(writer, request)
}

func (r *Router) Handle(method, path string, handler http.Handler) {
	r.engine.Handle(method, path, r.adapt(handler))
}

func (r *Router) Any(path string, handler http.Handler) { r.engine.Any(path, r.adapt(handler)) }

func (r *Router) Group(path string) httpx.RouterGroup {
	return &group{group: r.engine.Group(path)}
}

type group struct{ group *ginlib.RouterGroup }

func (g *group) Handle(method, path string, handler http.Handler) {
	g.group.Handle(method, path, adapt(handler))
}

func (g *group) Any(path string, handler http.Handler) { g.group.Any(path, adapt(handler)) }

func (g *group) Group(path string) httpx.RouterGroup {
	return &group{group: g.group.Group(path)}
}

func (r *Router) adapt(handler http.Handler) ginlib.HandlerFunc { return adapt(handler) }

func adapt(handler http.Handler) ginlib.HandlerFunc {
	return func(ctx *ginlib.Context) {
		params := make(map[string]string, len(ctx.Params))
		for _, param := range ctx.Params {
			params[param.Key] = param.Value
		}
		requestContext := httpx.WithRouteParams(ctx.Request.Context(), params)
		requestContext = httpx.WithRoutePattern(requestContext, ctx.FullPath())
		request := ctx.Request.WithContext(requestContext)
		handler.ServeHTTP(ctx.Writer, request)
	}
}