package handlers

import (
	"encoding/json"
	"net/http"

	"github.com/gin-gonic/gin"

	"armature/forms"
)

// FormsHandler provides REST endpoints for the standalone forms system.
type FormsHandler struct{}

// formsValidateRequest is the request body for POST /api/v1/forms/validate.
type formsValidateRequest struct {
	Template json.RawMessage        `json:"template"`
	Data     map[string]interface{} `json:"data"`
}

// formsValidateResponse is the response body for POST /api/v1/forms/validate.
type formsValidateResponse struct {
	Valid  bool              `json:"valid"`
	Errors []forms.FieldError `json:"errors"`
}

// Validate validates form data against a typed form template.
//
//	POST /api/v1/forms/validate
//	Body: { "template": {...}, "data": {...} }
//	Response: { "valid": true/false, "errors": [...] }
func (h *FormsHandler) Validate(c *gin.Context) {
	var req formsValidateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid request body"})
		return
	}

	if len(req.Template) == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "template is required"})
		return
	}

	tpl := forms.ParseTypedFormTemplate(req.Template)
	if tpl == nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "template is invalid or empty"})
		return
	}

	if req.Data == nil {
		req.Data = make(map[string]interface{})
	}

	errs := forms.ValidateFormData(tpl, req.Data)
	if errs == nil {
		errs = []forms.FieldError{}
	}

	c.JSON(http.StatusOK, formsValidateResponse{
		Valid:  len(errs) == 0,
		Errors: errs,
	})
}