package templating

import (
	"farga/config"
	"farga/db/types"
	"farga/lib/mime"
	"html/template"
	"io/fs"
	"log"
	"maps"
	"net/http"
	"path/filepath"
	"strings"

	"farga/lib"

	"embed"

	"github.com/gorilla/csrf"
)

//go:embed views
var templatesFS embed.FS

var FuncMap = template.FuncMap{
	"GetMime":     mime.Type,
	"IsImage":     mime.IsImage,
	"IsVideo":     mime.IsVideo,
	"IsText":      mime.IsText,
	"Src":         mime.Src,
	"Str":         mime.ToStr,
	"RepoRoot":    lib.RepoRoot,
	"SizeOf":      lib.Size,
	"SizeLen":     lib.SizeLen,
	"IsRangeable": lib.IsRangeable,
	"TruncateStr": lib.TruncateString,
	"SplitLines":  lib.SplitLines,
}

func findAndParseTemplates(fsys fs.FS, root string, funcMap template.FuncMap) (*template.Template, error) {
	rootTmpl := template.New("").Funcs(funcMap)

	err := fs.WalkDir(fsys, root, func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}

		if d.IsDir() || !strings.HasSuffix(path, ".html") {
			return nil
		}

		b, err := fs.ReadFile(fsys, path)
		if err != nil {
			return err
		}

		name := strings.TrimPrefix(path, root+"/")

		_, err = rootTmpl.New(name).Parse(string(b))
		return err
	})

	if err != nil {
		return nil, err
	}

	return rootTmpl, nil
}

var templates *template.Template

func init() {
	var err error
	templates, err = findAndParseTemplates(templatesFS, ".", FuncMap)
	if err != nil {
		log.Fatal(err)
	}
}

// Renders a template inside a given layout. You can also pass it any data.
func Render(w http.ResponseWriter, r *http.Request, layout, page string, data ...any) {
	var td = make(map[string]any)
	if len(data) > 0 {
		if m, ok := data[0].(map[string]any); ok {
			maps.Copy(td, m)
		} else {
			// if data was something else, store it under "data"
			td["data"] = data[0]
		}
	}

	tmpl, err := templates.Clone()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	tmpl, err = tmpl.ParseFiles(filepath.Join("templating", "views", page+".html"))
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	if v := r.Context().Value(lib.ErrorKey); v != nil {
		td["error"] = v
	}

	if v := r.Context().Value(lib.MessageKey); v != nil {
		if s, ok := v.(string); ok && s != "" {
			td["message"] = s
		}
	}

	user, ok := r.Context().Value(lib.UserKey).(*types.User)
	if ok {
		td["user"] = user
		td["loggedIn"] = true
	} else {
		td["loggedIn"] = false // no user = not logged in.
	}

	td["sshDomain"] = config.C.Domain
	td["sshPort"] = config.C.SSHPort

	td["csrfField"] = csrf.TemplateField(r) // append {{ .csrfField }} to every form.

	err = tmpl.ExecuteTemplate(w, layout, td)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}