package app

import (
	"errors"
	"net/http"

	"{{GO_MODULE}}/pkg/httperror"
	"{{GO_MODULE}}/pkg/httpresponse"
	"{{GO_MODULE}}/pkg/httpvalidation"
)

// Bind decodes JSON from the request body into v.
// Returns an HTTPError on failure that can be returned directly from a HandlerFunc.
//
// Usage:
//
//	func CreateUser(w http.ResponseWriter, r *http.Request) error {
//	    var req CreateUserRequest
//	    if err := app.Bind(r, &req); err != nil {
//	        return err // Returns typed HTTPError
//	    }
//	    // req is now decoded
//	}
func Bind(r *http.Request, v any) error {
	if err := httpresponse.DecodeJSON(r, v); err != nil {
		if errors.Is(err, httpresponse.ErrEmptyBody) {
			return httperror.BadRequest("request body is required")
		}
		return httperror.BadRequest("invalid request body")
	}
	return nil
}

// BindStrict decodes JSON from the request body with strict field checking.
// Unknown fields in the JSON will cause an error.
func BindStrict(r *http.Request, v any) error {
	if err := httpresponse.DecodeJSONStrict(r, v); err != nil {
		if errors.Is(err, httpresponse.ErrEmptyBody) {
			return httperror.BadRequest("request body is required")
		}
		if errors.Is(err, httpresponse.ErrUnknownFields) {
			return httperror.BadRequest("unknown fields in request body")
		}
		return httperror.BadRequest("invalid request body")
	}
	return nil
}

// BindAndValidate decodes JSON and validates using httpvalidation.
// Returns a validation error with field-level details if validation fails.
//
// Usage:
//
//	type CreateUserRequest struct {
//	    Name  string `json:"name" validate:"required,min=1,max=100"`
//	    Email string `json:"email" validate:"required,email"`
//	}
//
//	func CreateUser(w http.ResponseWriter, r *http.Request) error {
//	    var req CreateUserRequest
//	    if err := app.BindAndValidate(r, &req); err != nil {
//	        return err
//	    }
//	    // req is decoded and validated
//	}
func BindAndValidate(r *http.Request, v any) error {
	// Decode JSON
	if err := Bind(r, v); err != nil {
		return err
	}

	// Validate struct
	if details := httpvalidation.ValidateStruct(v); len(details) > 0 {
		return httperror.WithDetails(httperror.Validation("validation failed"), details)
	}

	return nil
}

// BindAndValidateStrict decodes JSON with strict field checking and validates.
func BindAndValidateStrict(r *http.Request, v any) error {
	// Decode JSON strictly
	if err := BindStrict(r, v); err != nil {
		return err
	}

	// Validate struct
	if details := httpvalidation.ValidateStruct(v); len(details) > 0 {
		return httperror.WithDetails(httperror.Validation("validation failed"), details)
	}

	return nil
}
