source: code/trunk/zs.go@ 23

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

// 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{
                "file":   path,
                "url":    url,
                "output": filepath.Join(PUBDIR, url),
        }
        if _, err := os.Stat(filepath.Join(ZSDIR, "layout.amber")); err == nil {
                v["layout"] = "layout.amber"
        } else {
                v["layout"] = "layout.html"
        }

        if info, err := os.Stat(path); err == nil {
                v["date"] = info.ModTime().Format("02-01-2006")
        }
        for name, value := range globals {
                v[name] = value
        }
        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, funcs template.FuncMap, vars Vars) (string, error) {
        f := template.FuncMap{}
        for k, v := range funcs {
                f[k] = v
        }
        for k, v := range vars {
                f[k] = varFunc(v)
        }
        tmpl, err := template.New("").Funcs(f).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
}

// 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
}

// Expands macro: either replacing it with the variable value, or
// running the plugin command and replacing it with the command's output
func eval(cmd []string, vars Vars) (string, error) {
        outbuf := bytes.NewBuffer(nil)
        err := run(path.Join(ZSDIR, cmd[0]), cmd[1:], vars, outbuf)
        if err != nil {
                if _, ok := err.(*exec.ExitError); ok {
                        return "", err
                }
                outbuf = bytes.NewBuffer(nil)
                err := run(cmd[0], cmd[1:], vars, outbuf)
                // Return exit errors, but ignore if the command was not found
                if _, ok := err.(*exec.ExitError); ok {
                        return "", err
                }
        }
        return outbuf.String(), nil
}

// Renders markdown with the given layout into html expanding all the macros
func buildMarkdown(path string, funcs template.FuncMap, vars Vars) error {
        v, body, err := md(path, vars)
        if err != nil {
                return err
        }
        content, err := render(body, funcs, v)
        if err != nil {
                return err
        }
        v["content"] = string(blackfriday.MarkdownBasic([]byte(content)))
        if strings.HasSuffix(v["layout"], ".amber") {
                return buildAmber(filepath.Join(ZSDIR, v["layout"]),
                        renameExt(path, "", ".html"), funcs, v)
        } else {
                return buildPlain(filepath.Join(ZSDIR, v["layout"]),
                        renameExt(path, "", ".html"), funcs, v)
        }
}

// Renders text file expanding all variable macros inside it
func buildPlain(in, out string, funcs template.FuncMap, vars Vars) error {
        b, err := ioutil.ReadFile(in)
        if err != nil {
                return err
        }
        content, err := render(string(b), funcs, vars)
        if err != nil {
                return err
        }
        output := filepath.Join(PUBDIR, out)
        if s, ok := vars["output"]; ok {
                output = s
        }
        err = ioutil.WriteFile(output, []byte(content), 0666)
        if err != nil {
                return err
        }
        return nil
}

// Renders .amber file into .html
func buildAmber(in, out string, funcs template.FuncMap, vars Vars) error {
        a := amber.New()
        err := a.ParseFile(in)
        if err != nil {
                return err
        }
        t, err := a.Compile()
        if err != nil {
                return err
        }
        //amber.FuncMap = amber.FuncMap
        f, err := os.Create(filepath.Join(PUBDIR, out))
        if err != nil {
                return err
        }
        defer f.Close()
        return t.Execute(f, vars)
}

// Compiles .gcss into .css
func buildGCSS(path string) error {
        f, err := os.Open(path)
        if err != nil {
                return err
        }
        s := strings.TrimSuffix(path, ".gcss") + ".css"
        css, err := os.Create(filepath.Join(PUBDIR, s))
        if err != nil {
                return err
        }

        defer f.Close()
        defer css.Close()

        _, err = gcss.Compile(css, f)
        return err
}

// Copies file from working directory into public directory
func copyFile(path string) (err error) {
        var in, out *os.File
        if in, err = os.Open(path); err == nil {
                defer in.Close()
                if out, err = os.Create(filepath.Join(PUBDIR, path)); err == nil {
                        defer out.Close()
                        _, err = io.Copy(out, in)
                }
        }
        return err
}

func varFunc(s string) func() string {
        return func() string {
                return s
        }
}

func pluginFunc(cmd string) func() string {
        return func() string {
                return "Not implemented yet"
        }
}

func createFuncs() template.FuncMap {
        // Builtin functions
        funcs := template.FuncMap{
                "exec": func(s ...string) string {
                        // Run external command with arguments
                        return ""
                },
                "zs": func(args ...string) string {
                        // Run zs with arguments
                        return ""
                },
        }
        // Plugin functions
        files, _ := ioutil.ReadDir(ZSDIR)
        for _, f := range files {
                if !f.IsDir() {
                        name := f.Name()
                        if !strings.HasSuffix(name, ".html") && !strings.HasSuffix(name, ".amber") {
                                funcs[strings.TrimSuffix(name, filepath.Ext(name))] = pluginFunc(name)
                        }
                }
        }
        return funcs
}

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

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
}

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

        vars := globals()
        for {
                os.Mkdir(PUBDIR, 0755)
                funcs := createFuncs()
                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
                        }

                        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
                                }
                                ext := filepath.Ext(path)
                                if ext == ".md" || ext == ".mkd" {
                                        log.Println("md: ", path)
                                        return buildMarkdown(path, funcs, vars)
                                } else if ext == ".html" || ext == ".xml" {
                                        log.Println("html: ", path)
                                        return buildPlain(path, path, funcs, vars)
                                } else if ext == ".amber" {
                                        log.Println("html: ", path)
                                        return buildAmber(path, renameExt(path, ".amber", ".html"), funcs, vars)
                                } else if ext == ".gcss" {
                                        log.Println("css: ", path)
                                        return buildGCSS(path)
                                } else {
                                        log.Println("raw: ", path)
                                        return copyFile(path)
                                }
                        }
                        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
                }
                lastModified = time.Now()
                if once {
                        break
                }
                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":
                buildAll(true)
        case "watch":
                buildAll(false) // pass duration
        case "var":
                if len(args) == 0 {
                        log.Println("ERROR: filename expected")
                        return
                }
                if vars, _, err := md(args[0], globals()); err == nil {
                        if len(args) > 1 {
                                for _, a := range args[1:] {
                                        fmt.Println(vars[a])
                                }
                        } else {
                                for k, v := range vars {
                                        fmt.Println(k + ":" + v)
                                }
                        }
                } else {
                        log.Println("ERROR:", err)
                }
        default:
                err := run(path.Join(ZSDIR, cmd), args, Vars{}, os.Stdout)
                if err != nil {
                        log.Println("ERROR:", err)
                }
        }
}