Add Templates with Parsing

+ Changes NewComposer to return error.
+ Add lib to handle templates using "text/template".
+ Add -T option to following commands
    - compose.
    - reply
    - forward
+ Quoted replies using templates.
+ Forwards as body using templates
+ Default templates are installed similar to filters.
+ Templates Config in aerc.conf.
    - Required templates are parsed while loading config.
+ Add aerc-templates.7 manual for using template data.

4 files changed, 132 insertions, 126 deletions

diff --git a/commands/account/compose.go b/commands/account/compose.go
index 039eb923..24e460b3 100644
--- a/commands/account/compose.go
+++ b/commands/account/compose.go
@@ -24,13 +24,17 @@ func (Compose) Complete(aerc *widgets.Aerc, args []string) []string {
 }
 
 func (Compose) Execute(aerc *widgets.Aerc, args []string) error {
-	body, err := buildBody(args)
+	body, template, err := buildBody(args)
 	if err != nil {
 		return err
 	}
 	acct := aerc.SelectedAccount()
-	composer := widgets.NewComposer(aerc,
-		aerc.Config(), acct.AccountConfig(), acct.Worker(), nil)
+
+	composer, err := widgets.NewComposer(aerc,
+		aerc.Config(), acct.AccountConfig(), acct.Worker(), template, nil)
+	if err != nil {
+		return err
+	}
 	tab := aerc.NewTab(composer, "New email")
 	composer.OnHeaderChange("Subject", func(subject string) {
 		if subject == "" {
@@ -44,11 +48,11 @@ func (Compose) Execute(aerc *widgets.Aerc, args []string) error {
 	return nil
 }
 
-func buildBody(args []string) (string, error) {
-	var body, headers string
-	opts, optind, err := getopt.Getopts(args, "H:")
+func buildBody(args []string) (string, string, error) {
+	var body, template, headers string
+	opts, optind, err := getopt.Getopts(args, "H:T:")
 	if err != nil {
-		return "", err
+		return "", "", err
 	}
 	for _, opt := range opts {
 		switch opt.Option {
@@ -60,11 +64,13 @@ func buildBody(args []string) (string, error) {
 			} else {
 				headers += opt.Value + ":\n"
 			}
+		case 'T':
+			template = opt.Value
 		}
 	}
 	posargs := args[optind:]
 	if len(posargs) > 1 {
-		return "", errors.New("Usage: compose [-H] [body]")
+		return "", template, errors.New("Usage: compose [-H] [body]")
 	}
 	if len(posargs) == 1 {
 		body = posargs[0]
@@ -76,5 +82,5 @@ func buildBody(args []string) (string, error) {
 			body = headers + "\n\n"
 		}
 	}
-	return body, nil
+	return body, template, nil
 }
diff --git a/commands/msg/forward.go b/commands/msg/forward.go
index 494072d0..75701772 100644
--- a/commands/msg/forward.go
+++ b/commands/msg/forward.go
@@ -1,20 +1,21 @@
 package msg
 
 import (
-	"bufio"
+	"bytes"
 	"errors"
 	"fmt"
-	"git.sr.ht/~sircmpwn/aerc/lib"
-	"git.sr.ht/~sircmpwn/aerc/models"
-	"git.sr.ht/~sircmpwn/aerc/widgets"
-	"git.sr.ht/~sircmpwn/getopt"
-	"github.com/emersion/go-message"
-	"github.com/emersion/go-message/mail"
 	"io"
 	"io/ioutil"
 	"os"
 	"path"
 	"strings"
+
+	"github.com/emersion/go-message"
+	"github.com/emersion/go-message/mail"
+
+	"git.sr.ht/~sircmpwn/aerc/models"
+	"git.sr.ht/~sircmpwn/aerc/widgets"
+	"git.sr.ht/~sircmpwn/getopt"
 )
 
 type forward struct{}
@@ -32,15 +33,18 @@ func (forward) Complete(aerc *widgets.Aerc, args []string) []string {
 }
 
 func (forward) Execute(aerc *widgets.Aerc, args []string) error {
-	opts, optind, err := getopt.Getopts(args, "A")
+	opts, optind, err := getopt.Getopts(args, "AT:")
 	if err != nil {
 		return err
 	}
 	attach := false
+	template := ""
 	for _, opt := range opts {
 		switch opt.Option {
 		case 'A':
 			attach = true
+		case 'T':
+			template = opt.Value
 		}
 	}
 
@@ -69,10 +73,20 @@ func (forward) Execute(aerc *widgets.Aerc, args []string) error {
 		"To":      to,
 		"Subject": subject,
 	}
-	composer := widgets.NewComposer(aerc, aerc.Config(), acct.AccountConfig(),
-		acct.Worker(), defaults)
 
-	addTab := func() {
+	addTab := func() (*widgets.Composer, error) {
+		if template != "" {
+			defaults["OriginalFrom"] = models.FormatAddresses(msg.Envelope.From)
+			defaults["OriginalDate"] = msg.Envelope.Date.Format("Mon Jan 2, 2006 at 3:04 PM")
+		}
+
+		composer, err := widgets.NewComposer(aerc, aerc.Config(), acct.AccountConfig(),
+			acct.Worker(), template, defaults)
+		if err != nil {
+			aerc.PushError("Error: " + err.Error())
+			return nil, err
+		}
+
 		tab := aerc.NewTab(composer, subject)
 		if to == "" {
 			composer.FocusRecipient()
@@ -87,83 +101,68 @@ func (forward) Execute(aerc *widgets.Aerc, args []string) error {
 			}
 			tab.Content.Invalidate()
 		})
+		return composer, nil
 	}
 
 	if attach {
-		forwardAttach(store, composer, msg, addTab)
-	} else {
-		forwardBodyPart(store, composer, msg, addTab)
-	}
-	return nil
-}
-
-func forwardAttach(store *lib.MessageStore, composer *widgets.Composer,
-	msg *models.MessageInfo, addTab func()) {
-
-	store.FetchFull([]uint32{msg.Uid}, func(reader io.Reader) {
 		tmpDir, err := ioutil.TempDir("", "aerc-tmp-attachment")
 		if err != nil {
-			// TODO: Do something with the error
-			addTab()
-			return
+			return err
 		}
 		tmpFileName := path.Join(tmpDir,
 			strings.ReplaceAll(fmt.Sprintf("%s.eml", msg.Envelope.Subject), "/", "-"))
-		tmpFile, err := os.Create(tmpFileName)
-		if err != nil {
-			println(err)
-			// TODO: Do something with the error
-			addTab()
-			return
-		}
+		store.FetchFull([]uint32{msg.Uid}, func(reader io.Reader) {
+			tmpFile, err := os.Create(tmpFileName)
+			if err != nil {
+				println(err)
+				// TODO: Do something with the error
+				addTab()
+				return
+			}
 
-		defer tmpFile.Close()
-		io.Copy(tmpFile, reader)
-		composer.AddAttachment(tmpFileName)
-		composer.OnClose(func(composer *widgets.Composer) {
-			os.RemoveAll(tmpDir)
+			defer tmpFile.Close()
+			io.Copy(tmpFile, reader)
+			composer, err := addTab()
+			if err != nil {
+				return
+			}
+			composer.AddAttachment(tmpFileName)
+			composer.OnClose(func(composer *widgets.Composer) {
+				os.RemoveAll(tmpDir)
+			})
 		})
-		addTab()
-	})
-}
-
-func forwardBodyPart(store *lib.MessageStore, composer *widgets.Composer,
-	msg *models.MessageInfo, addTab func()) {
-	// TODO: something more intelligent than fetching the 1st part
-	// TODO: add attachments!
-	store.FetchBodyPart(msg.Uid, []int{1}, func(reader io.Reader) {
-		header := message.Header{}
-		header.SetText(
-			"Content-Transfer-Encoding", msg.BodyStructure.Encoding)
-		header.SetContentType(
-			msg.BodyStructure.MIMEType, msg.BodyStructure.Params)
-		header.SetText("Content-Description", msg.BodyStructure.Description)
-		entity, err := message.New(header, reader)
-		if err != nil {
-			// TODO: Do something with the error
-			addTab()
-			return
-		}
-		mreader := mail.NewReader(entity)
-		part, err := mreader.NextPart()
-		if err != nil {
-			// TODO: Do something with the error
-			addTab()
-			return
+	} else {
+		if template == "" {
+			template = aerc.Config().Templates.Forwards
 		}
 
-		pipeout, pipein := io.Pipe()
-		scanner := bufio.NewScanner(part.Body)
-		go composer.PrependContents(pipeout)
-		// TODO: Let user customize the date format used here
-		io.WriteString(pipein, fmt.Sprintf("Forwarded message from %s on %s:\n\n",
-			msg.Envelope.From[0].Name,
-			msg.Envelope.Date.Format("Mon Jan 2, 2006 at 3:04 PM")))
-		for scanner.Scan() {
-			io.WriteString(pipein, fmt.Sprintf("%s\n", scanner.Text()))
-		}
-		pipein.Close()
-		pipeout.Close()
-		addTab()
-	})
+		// TODO: something more intelligent than fetching the 1st part
+		// TODO: add attachments!
+		store.FetchBodyPart(msg.Uid, []int{1}, func(reader io.Reader) {
+			header := message.Header{}
+			header.SetText(
+				"Content-Transfer-Encoding", msg.BodyStructure.Encoding)
+			header.SetContentType(
+				msg.BodyStructure.MIMEType, msg.BodyStructure.Params)
+			header.SetText("Content-Description", msg.BodyStructure.Description)
+			entity, err := message.New(header, reader)
+			if err != nil {
+				// TODO: Do something with the error
+				addTab()
+				return
+			}
+			mreader := mail.NewReader(entity)
+			part, err := mreader.NextPart()
+			if err != nil {
+				// TODO: Do something with the error
+				addTab()
+				return
+			}
+			buf := new(bytes.Buffer)
+			buf.ReadFrom(part.Body)
+			defaults["Original"] = buf.String()
+			addTab()
+		})
+	}
+	return nil
 }
diff --git a/commands/msg/reply.go b/commands/msg/reply.go
index 9ef7a3b8..b13e254a 100644
--- a/commands/msg/reply.go
+++ b/commands/msg/reply.go
@@ -1,7 +1,7 @@
 package msg
 
 import (
-	"bufio"
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -32,16 +32,17 @@ func (reply) Complete(aerc *widgets.Aerc, args []string) []string {
 }
 
 func (reply) Execute(aerc *widgets.Aerc, args []string) error {
-	opts, optind, err := getopt.Getopts(args, "aq")
+	opts, optind, err := getopt.Getopts(args, "aqT:")
 	if err != nil {
 		return err
 	}
 	if optind != len(args) {
-		return errors.New("Usage: reply [-aq]")
+		return errors.New("Usage: reply [-aq -T <template>]")
 	}
 	var (
 		quote    bool
 		replyAll bool
+		template string
 	)
 	for _, opt := range opts {
 		switch opt.Option {
@@ -49,11 +50,14 @@ func (reply) Execute(aerc *widgets.Aerc, args []string) error {
 			replyAll = true
 		case 'q':
 			quote = true
+		case 'T':
+			template = opt.Value
 		}
 	}
 
 	widget := aerc.SelectedTab().(widgets.ProvidesMessage)
 	acct := widget.SelectedAccount()
+
 	if acct == nil {
 		return errors.New("No account selected")
 	}
@@ -116,14 +120,23 @@ func (reply) Execute(aerc *widgets.Aerc, args []string) error {
 		"In-Reply-To": msg.Envelope.MessageId,
 	}
 
-	composer := widgets.NewComposer(aerc, aerc.Config(),
-		acct.AccountConfig(), acct.Worker(), defaults)
+	addTab := func() error {
+		if template != "" {
+			defaults["OriginalFrom"] = models.FormatAddresses(msg.Envelope.From)
+			defaults["OriginalDate"] = msg.Envelope.Date.Format("Mon Jan 2, 2006 at 3:04 PM")
+		}
 
-	if args[0] == "reply" {
-		composer.FocusTerminal()
-	}
+		composer, err := widgets.NewComposer(aerc, aerc.Config(),
+			acct.AccountConfig(), acct.Worker(), template, defaults)
+		if err != nil {
+			aerc.PushError("Error: " + err.Error())
+			return err
+		}
+
+		if args[0] == "reply" {
+			composer.FocusTerminal()
+		}
 
-	addTab := func() {
 		tab := aerc.NewTab(composer, subject)
 		composer.OnHeaderChange("Subject", func(subject string) {
 			if subject == "" {
@@ -133,27 +146,21 @@ func (reply) Execute(aerc *widgets.Aerc, args []string) error {
 			}
 			tab.Content.Invalidate()
 		})
+
+		return nil
 	}
 
 	if quote {
-		var (
-			path []int
-			part *models.BodyStructure
-		)
-		if len(msg.BodyStructure.Parts) != 0 {
-			part, path = findPlaintext(msg.BodyStructure, path)
-		}
-		if part == nil {
-			part = msg.BodyStructure
-			path = []int{1}
+		if template == "" {
+			template = aerc.Config().Templates.QuotedReply
 		}
 
-		store.FetchBodyPart(msg.Uid, path, func(reader io.Reader) {
+		store.FetchBodyPart(msg.Uid, []int{1}, func(reader io.Reader) {
 			header := message.Header{}
 			header.SetText(
-				"Content-Transfer-Encoding", part.Encoding)
-			header.SetContentType(part.MIMEType, part.Params)
-			header.SetText("Content-Description", part.Description)
+				"Content-Transfer-Encoding", msg.BodyStructure.Encoding)
+			header.SetContentType(msg.BodyStructure.MIMEType, msg.BodyStructure.Params)
+			header.SetText("Content-Description", msg.BodyStructure.Description)
 			entity, err := message.New(header, reader)
 			if err != nil {
 				// TODO: Do something with the error
@@ -168,25 +175,15 @@ func (reply) Execute(aerc *widgets.Aerc, args []string) error {
 				return
 			}
 
-			pipeout, pipein := io.Pipe()
-			scanner := bufio.NewScanner(part.Body)
-			go composer.PrependContents(pipeout)
-			// TODO: Let user customize the date format used here
-			io.WriteString(pipein, fmt.Sprintf("On %s %s wrote:\n",
-				msg.Envelope.Date.Format("Mon Jan 2, 2006 at 3:04 PM"),
-				msg.Envelope.From[0].Name))
-			for scanner.Scan() {
-				io.WriteString(pipein, fmt.Sprintf("> %s\n", scanner.Text()))
-			}
-			pipein.Close()
-			pipeout.Close()
+			buf := new(bytes.Buffer)
+			buf.ReadFrom(part.Body)
+			defaults["Original"] = buf.String()
 			addTab()
 		})
+		return nil
 	} else {
-		addTab()
+		return addTab()
 	}
-
-	return nil
 }
 
 func findPlaintext(bs *models.BodyStructure,
diff --git a/commands/msg/unsubscribe.go b/commands/msg/unsubscribe.go
index 15a9411c..5ffec465 100644
--- a/commands/msg/unsubscribe.go
+++ b/commands/msg/unsubscribe.go
@@ -87,13 +87,17 @@ func unsubscribeMailto(aerc *widgets.Aerc, u *url.URL) error {
 		"To":      u.Opaque,
 		"Subject": u.Query().Get("subject"),
 	}
-	composer := widgets.NewComposer(
+	composer, err := widgets.NewComposer(
 		aerc,
 		aerc.Config(),
 		acct.AccountConfig(),
 		acct.Worker(),
+		"",
 		defaults,
 	)
+	if err != nil {
+		return err
+	}
 	composer.SetContents(strings.NewReader(u.Query().Get("body")))
 	tab := aerc.NewTab(composer, "unsubscribe")
 	composer.OnHeaderChange("Subject", func(subject string) {