package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"os"
	"strings"
)

var (
	conf_f         = flag.String("c", "", "Path to the configuration file.")
	template_dir_f = flag.String("d", ".", "Template directory.")
	template_f     = flag.String("f", "", "Templates to render, a comma separated list.")
	ext_f          = flag.String("e", ".tmpl", "Extension of template files")
	is_html_f      = flag.Bool("html", false, "Enable HTML context sensitivy.")
)

func main() {
	flag.Parse()

	if *template_f == "" {
		fmt.Println("Please provide a template to render with the -f option.")
		os.Exit(1)
	}

	// Reading config from environment if not set (case insensitive)
	*conf_f = GetVarFromEnv(*conf_f, "config")
	*template_dir_f = GetVarFromEnv(*template_dir_f, "template_directory")
	*template_f = GetVarFromEnv(*template_f, "templates")

	// Read configuration file with the template data
	data := NewConfiguration(*conf_f)

	// Splits the templates
	var templates []string
	if strings.Contains(*template_f, ",") {
		templates = strings.Split(*template_f, ",")
	} else {
		templates = strings.Split(*template_f, " ")
	}

	// Clean out the filenames if they start with the template dirname (shell globbing)
	for index, template := range templates {
		if strings.HasPrefix(template, *template_dir_f+"/") {
			templates[index] = strings.TrimPrefix(template, *template_dir_f+"/")
		} else {
			templates[index] = strings.TrimPrefix(template, *template_dir_f)
		}
	}

	// Enable HTML context sensitivy on demand
	if *is_html_f {
		ParseHTML(templates, data)
	} else {
		ParseText(templates, data)
	}
}

func NewConfiguration(path string) interface{} {
	if path == "" {
		return nil
	}
	file, err := os.Open(path)
	if err != nil {
		log.Print("INFO: Error opening config file. Is it a valid file?")
		return nil
	}

	fi, err := file.Stat()
	if err != nil {
		log.Fatal(err)
	}

	data := make([]byte, int64(fi.Size()))
	file.Read(data)

	var json_data interface{}
	json.Unmarshal(data, &json_data)

	return json_data
}

func GetVarFromEnv(s, key string) string {
	if s == "" {
		s = os.Getenv(key)
	}
	if s == "" {
		s = os.Getenv(strings.ToUpper(key))
	}
	return s
}