package main

import (
    "bytes"
    "fmt"
    "github.com/namsral/flag"
    "golang.org/x/net/html"
    "golang.org/x/net/html/atom"
    "io"
    "io/ioutil"
    "os"
    "path/filepath"
    "strings"
)

var writeSuffix bool
var supportStyle bool

func main() {
    flag.BoolVar(&writeSuffix, "writeSuffix", false, "write '_gas' suffix to generated files")
    flag.BoolVar(&supportStyle, "supportStyle", false, "extract <style> to *filename*.*styles_type(default css)*")
    flag.Parse()

    goFile := os.Getenv("GOFILE")

    templates, err := filepath.Glob("*.gas")
    must(err)
    for _, file := range templates {
        parseFile(file, goFile)
    }
}

func parseFile(fileName string, gofile string) {
    fileBase := strings.TrimSuffix(fileName, ".gas")

    var filename string
    if writeSuffix {
        filename = fileBase + "_gas" + ".go"
    } else {
        filename = fileBase + ".go"
    }

    // Prevent overwriting the file calling gasx via go generate.
    if filename == gofile {
        panic(fmt.Errorf("file conflict on name: %s", filename))
    }

    // Open the .gas file.
    fileBytes, err := ioutil.ReadFile(fileName)
    must(err)

    // Read and .gas file.
    buf := bytes.NewBuffer(fileBytes)

    // Parse the .gas file file into html nodes.
    nodes := parse(buf)
    fileTags, err := parseTemplate(nodes)
    must(err)

    buf.Reset()
    must(html.Render(buf, firstChild(fileTags["template"])))

    template := executeEl(parseNode(buf.String()), true)

    // Write the source as a Go file.
    osFile, err := os.Create(filename)
    must(err)

    script  := textChild(fileTags["script"])
    varName := fileBase + "T"
    varI    := strings.Index(script, varName)
    script   = script[:varI] + template + script[varI+len(varName):] // replace varName to parsedTemplate

    writeString(osFile, fmt.Sprintf("// Code generated by gasx. DO NOT EDIT.\n// source: %s.gas", fileBase))
    writeString(osFile, script)

    style := fileTags["style"]
    if supportStyle && style != nil {
        styleType := getXAttr(style.Attr, "type")
        if len(styleType) == 0 {
            styleType = "css"
        }

        styleFile, err := os.Create(fileBase+"."+styleType)
        must(err)

        writeString(styleFile, textChild(style))
    }

    err = osFile.Close()
    must(err)
}