source: code/trunk/zs.go@ 33

package main

import (
        "bytes"
        "fmt"
        "io"
        "io/ioutil"
        "log"
        "os"
        "os/exec"
        "path"
        "path/filepath"
        "strings"
        "text/template"
        "time"

        "github.com/eknkc/amber"
        "github.com/russross/blackfriday"
        "github.com/yosssi/gcss"
)

const (
        ZSDIR  = ".zs"
        PUBDIR = ".pub"
)

type Vars map[string]string

func renameExt(path, from, to string) string {
        if from == "" {
                from = filepath.Ext(path)
        }
        if strings.HasSuffix(path, from) {
                return strings.TrimSuffix(path, from) + to
        } else {
                return path
        }
}

func globals() Vars {
        vars := Vars{}
        for _, e := range os.Environ() {
                pair := strings.Split(e, "=")
                if strings.HasPrefix(pair[0], "ZS_") {
                        vars[strings.ToLower(pair[0][3:])] = pair[1]
                }
        }
        return vars
}

// Converts zs markdown variables into environment variables
func env(vars Vars) []string {
        env := []string{"ZS=" + os.Args[0], "ZS_OUTDIR=" + PUBDIR}
        env = append(env, os.Environ()...)
        if vars != nil {
                for k, v := range vars {
                        env = append(env, "ZS_"+strings.ToUpper(k)+"="+v)
                }
        }
        return env
}

// Runs command with given arguments and variables, intercepts stderr and
// redirects stdout into the given writer
func run(cmd string, args []string, vars Vars, output io.Writer) error {
        var errbuf bytes.Buffer
        c := exec.Command(cmd, args...)
        c.Env = env(vars)
        c.Stdout = output
        c.Stderr = &errbuf

        err := c.Run()

        if errbuf.Len() > 0 {
                log.Println("ERROR:", errbuf.String())
        }

        if err != nil {
                return err
        }
        return nil
}

// Splits a string in exactly two parts by delimiter
// If no delimiter is found - the second string is be empty
func split2(s, delim string) (string, string) {
        parts := strings.SplitN(s, delim, 2)
        if len(parts) == 2 {
                return parts[0], parts[1]
        } else {
                return parts[0], ""
        }
}

// Parses markdown content. Returns parsed header variables and content
func md(path string, globals Vars) (Vars, string, error) {
        b, err := ioutil.ReadFile(path)
        if err != nil {
                return nil, "", err
        }
        s := string(b)
        url := path[:len(path)-len(filepath.Ext(path))] + ".html"
        v := Vars{
                "title":       "",
                "description": "",
                "keywords":    "",
        }
        for name, value := range globals {
                v[name] = value
        }
        if _, err := os.Stat(filepath.Join(ZSDIR, "layout.amber")); err == nil {
                v["layout"] = "layout.amber"
        } else {
                v["layout"] = "layout.html"
        }
        v["file"] = path
        v["url"] = url
        v["output"] = filepath.Join(PUBDIR, url)

        if strings.Index(s, "\n\n") == -1 {
                return v, s, nil
        }
        header, body := split2(s, "\n\n")
        for _, line := range strings.Split(header, "\n") {
                key, value := split2(line, ":")
                v[strings.ToLower(strings.TrimSpace(key))] = strings.TrimSpace(value)
        }
        if strings.HasPrefix(v["url"], "./") {
                v["url"] = v["url"][2:]
        }
        return v, body, nil
}

// Use standard Go templates
func render(s string, vars Vars) (string, error) {
        tmpl, err := template.New("").Parse(s)
        if err != nil {
                return "", err
        }
        out := &bytes.Buffer{}
        if err := tmpl.Execute(out, vars); err != nil {
                return "", err
        }
        return string(out.Bytes()), nil
}

// Renders markdown with the given layout into html expanding all the macros
func buildMarkdown(path string, w io.Writer, vars Vars) error {
        v, body, err := md(path, vars)
        if err != nil {
                return err
        }
        content, err := render(body, v)
        if err != nil {
                return err
        }
        v["content"] = string(blackfriday.MarkdownCommon([]byte(content)))
        if w == nil {
                out, err := os.Create(filepath.Join(PUBDIR, renameExt(path, "", ".html")))
                if err != nil {
                        return err
                }
                defer out.Close()
                w = out
        }
        if strings.HasSuffix(v["layout"], ".amber") {
                return buildAmber(filepath.Join(ZSDIR, v["layout"]), w, v)
        } else {
                return buildHTML(filepath.Join(ZSDIR, v["layout"]), w, v)
        }
}

// Renders text file expanding all variable macros inside it
func buildHTML(path string, w io.Writer, vars Vars) error {
        b, err := ioutil.ReadFile(path)
        if err != nil {
                return err
        }
        content, err := render(string(b), vars)
        if err != nil {
                return err
        }
        if w == nil {
                f, err := os.Create(filepath.Join(PUBDIR, path))
                if err != nil {
                        return err
                }
                defer f.Close()
                w = f
        }
        _, err = io.WriteString(w, content)
        return err
}

// Renders .amber file into .html
func buildAmber(path string, w io.Writer, vars Vars) error {
        a := amber.New()
        err := a.ParseFile(path)
        if err != nil {
                return err
        }

        data := map[string]interface{}{}
        for k, v := range vars {
                data[k] = v
        }

        t, err := a.Compile()
        if err != nil {
                return err
        }
        if w == nil {
                f, err := os.Create(filepath.Join(PUBDIR, renameExt(path, ".amber", ".html")))
                if err != nil {
                        return err
                }
                defer f.Close()
                w = f
        }
        return t.Execute(w, data)
}

// Compiles .gcss into .css
func buildGCSS(path string, w io.Writer) error {
        f, err := os.Open(path)
        if err != nil {
                return err
        }
        defer f.Close()

        if w == nil {
                s := strings.TrimSuffix(path, ".gcss") + ".css"
                css, err := os.Create(filepath.Join(PUBDIR, s))
                if err != nil {
                        return err
                }
                defer css.Close()
                w = css
        }
        _, err = gcss.Compile(w, f)
        return err
}

// Copies file as is from path to writer
func buildRaw(path string, w io.Writer) error {
        in, err := os.Open(path)
        if err != nil {
                return err
        }
        defer in.Close()
        if w == nil {
                if out, err := os.Create(filepath.Join(PUBDIR, path)); err != nil {
                        return err
                } else {
                        defer out.Close()
                        w = out
                }
        }
        _, err = io.Copy(w, in)
        return err
}

func build(path string, w io.Writer, vars Vars) error {
        ext := filepath.Ext(path)
        if ext == ".md" || ext == ".mkd" {
                return buildMarkdown(path, w, vars)
        } else if ext == ".html" || ext == ".xml" {
                return buildHTML(path, w, vars)
        } else if ext == ".amber" {
                return buildAmber(path, w, vars)
        } else if ext == ".gcss" {
                return buildGCSS(path, w)
        } else {
                return buildRaw(path, w)
        }
}

func buildAll(watch bool) {
        lastModified := time.Unix(0, 0)
        modified := false

        vars := globals()
        for {
                os.Mkdir(PUBDIR, 0755)
                err := filepath.Walk(".", func(path string, info os.FileInfo, err error) error {
                        // ignore hidden files and directories
                        if filepath.Base(path)[0] == '.' || strings.HasPrefix(path, ".") {
                                return nil
                        }
                        // inform user about fs walk errors, but continue iteration
                        if err != nil {
                                log.Println("ERROR:", err)
                                return nil
                        }

                        if info.IsDir() {
                                os.Mkdir(filepath.Join(PUBDIR, path), 0755)
                                return nil
                        } else if info.ModTime().After(lastModified) {
                                if !modified {
                                        // About to be modified, so run pre-build hook
                                        // FIXME on windows it might not work well
                                        run(filepath.Join(ZSDIR, "pre"), []string{}, nil, nil)
                                        modified = true
                                }
                                log.Println("build: ", path)
                                return build(path, nil, vars)
                        }
                        return nil
                })
                if err != nil {
                        log.Println("ERROR:", err)
                }
                if modified {
                        // Something was modified, so post-build hook
                        // FIXME on windows it might not work well
                        run(filepath.Join(ZSDIR, "post"), []string{}, nil, nil)
                        modified = false
                }
                if !watch {
                        break
                }
                lastModified = time.Now()
                time.Sleep(1 * time.Second)
        }
}

func main() {
        if len(os.Args) == 1 {
                fmt.Println(os.Args[0], "<command> [args]")
                return
        }
        cmd := os.Args[1]
        args := os.Args[2:]
        switch cmd {
        case "build":
                if len(args) == 0 {
                        buildAll(false)
                } else if len(args) == 1 {
                        if err := build(args[0], os.Stdout, globals()); err != nil {
                                fmt.Println("ERROR: " + err.Error())
                        }
                } else {
                        fmt.Println("ERROR: too many arguments")
                }
        case "watch":
                buildAll(true)
        case "var":
                if len(args) == 0 {
                        fmt.Println("var: filename expected")
                } else {
                        s := ""
                        if vars, _, err := md(args[0], globals()); err != nil {
                                fmt.Println("var: " + err.Error())
                        } else {
                                if len(args) > 1 {
                                        for _, a := range args[1:] {
                                                s = s + vars[a] + "\n"
                                        }
                                } else {
                                        for k, v := range vars {
                                                s = s + k + ":" + v + "\n"
                                        }
                                }
                        }
                        fmt.Println(strings.TrimSpace(s))
                }
        default:
                err := run(path.Join(ZSDIR, cmd), args, globals(), os.Stdout)
                if err != nil {
                        log.Println("ERROR:", err)
                }
        }
}