// Filename: internal/pongo/renderer.go

package pongo

import (
	"fmt"
	"net/http"

	"github.com/flosch/pongo2/v6"
	"github.com/gin-gonic/gin"
	"github.com/gin-gonic/gin/render"
)

type Renderer struct {
	Context pongo2.Context
	tplSet  *pongo2.TemplateSet
}

func New(directory string, isDebug bool) *Renderer {
	loader := pongo2.MustNewLocalFileSystemLoader(directory)
	tplSet := pongo2.NewSet("gin-pongo-templates", loader)
	tplSet.Debug = isDebug
	return &Renderer{Context: make(pongo2.Context), tplSet: tplSet}
}

// Instance returns a new render.HTML instance for a single request.
func (p *Renderer) Instance(name string, data interface{}) render.Render {
	var glob pongo2.Context
	if p.Context != nil {
		glob = p.Context
	}

	var context pongo2.Context
	if data != nil {
		if ginContext, ok := data.(gin.H); ok {
			context = pongo2.Context(ginContext)
		} else if pongoContext, ok := data.(pongo2.Context); ok {
			context = pongoContext
		} else if m, ok := data.(map[string]interface{}); ok {
			context = m
		} else {
			context = make(pongo2.Context)
		}
	} else {
		context = make(pongo2.Context)
	}

	for k, v := range glob {
		if _, ok := context[k]; !ok {
			context[k] = v
		}
	}

	tpl, err := p.tplSet.FromCache(name)
	if err != nil {
		panic(fmt.Sprintf("Failed to load template '%s': %v", name, err))
	}

	return &HTML{
		p:        p,
		Template: tpl,
		Name:     name,
		Data:     context,
	}
}

type HTML struct {
	p        *Renderer
	Template *pongo2.Template
	Name     string
	Data     pongo2.Context
}

func (h *HTML) Render(w http.ResponseWriter) error {
	h.WriteContentType(w)
	bytes, err := h.Template.ExecuteBytes(h.Data)
	if err != nil {
		return err
	}
	_, err = w.Write(bytes)
	return err
}

func (h *HTML) WriteContentType(w http.ResponseWriter) {
	header := w.Header()
	if val := header["Content-Type"]; len(val) == 0 {
		header["Content-Type"] = []string{"text/html; charset=utf-8"}
	}
}

func C(ctx *gin.Context) pongo2.Context {
	p, exists := ctx.Get("pongo2")
	if exists {
		if pCtx, ok := p.(pongo2.Context); ok {
			return pCtx
		}
	}
	pCtx := make(pongo2.Context)
	ctx.Set("pongo2", pCtx)
	return pCtx
}