package lib

import (
	"errors"
	"fmt"
	"strings"
	"unicode"

	"git.sr.ht/~sircmpwn/aerc/config"
	"git.sr.ht/~sircmpwn/aerc/models"
)

func ParseIndexFormat(conf *config.AercConfig, number int,
	msg *models.MessageInfo) (string, []interface{}, error) {

	format := conf.Ui.IndexFormat
	retval := make([]byte, 0, len(format))
	var args []interface{}

	var c rune
	for i, ni := 0, 0; i < len(format); {
		ni = strings.IndexByte(format[i:], '%')
		if ni < 0 {
			ni = len(format)
			retval = append(retval, []byte(format[i:ni])...)
			break
		}
		ni += i + 1
		// Check for fmt flags
		if ni == len(format) {
			goto handle_end_error
		}
		c = rune(format[ni])
		if c == '+' || c == '-' || c == '#' || c == ' ' || c == '0' {
			ni++
		}

		// Check for precision and width
		if ni == len(format) {
			goto handle_end_error
		}
		c = rune(format[ni])
		for unicode.IsDigit(c) {
			ni++
			c = rune(format[ni])
		}
		if c == '.' {
			ni++
			c = rune(format[ni])
			for unicode.IsDigit(c) {
				ni++
				c = rune(format[ni])
			}
		}

		retval = append(retval, []byte(format[i:ni])...)
		// Get final format verb
		if ni == len(format) {
			goto handle_end_error
		}
		c = rune(format[ni])
		switch c {
		case '%':
			retval = append(retval, '%')
		case 'a':
			if len(msg.Envelope.From) == 0 {
				return "", nil, errors.New("found no address for sender")
			}
			addr := msg.Envelope.From[0]
			retval = append(retval, 's')
			args = append(args, fmt.Sprintf("%s@%s", addr.Mailbox, addr.Host))
		case 'A':
			var addr *models.Address
			if len(msg.Envelope.ReplyTo) == 0 {
				if len(msg.Envelope.From) == 0 {
					return "", nil,
						errors.New("found no address for sender or reply-to")
				} else {
					addr = msg.Envelope.From[0]
				}
			} else {
				addr = msg.Envelope.ReplyTo[0]
			}
			retval = append(retval, 's')
			args = append(args, fmt.Sprintf("%s@%s", addr.Mailbox, addr.Host))
		case 'C':
			retval = append(retval, 'd')
			args = append(args, number)
		case 'd':
			retval = append(retval, 's')
			args = append(args, msg.InternalDate.Format(conf.Ui.TimestampFormat))
		case 'D':
			retval = append(retval, 's')
			args = append(args, msg.InternalDate.Local().Format(conf.Ui.TimestampFormat))
		case 'f':
			if len(msg.Envelope.From) == 0 {
				return "", nil, errors.New("found no address for sender")
			}
			addr := msg.Envelope.From[0].Format()
			retval = append(retval, 's')
			args = append(args, addr)
		case 'F':
			if len(msg.Envelope.From) == 0 {
				return "", nil, errors.New("found no address for sender")
			}
			addr := msg.Envelope.From[0]
			// TODO: handle case when sender is current user. Then
			// use recipient's name
			var val string
			if addr.Name != "" {
				val = addr.Name
			} else {
				val = fmt.Sprintf("%s@%s", addr.Mailbox, addr.Host)
			}
			retval = append(retval, 's')
			args = append(args, val)

		case 'i':
			retval = append(retval, 's')
			args = append(args, msg.Envelope.MessageId)
		case 'n':
			if len(msg.Envelope.From) == 0 {
				return "", nil, errors.New("found no address for sender")
			}
			addr := msg.Envelope.From[0]
			var val string
			if addr.Name != "" {
				val = addr.Name
			} else {
				val = fmt.Sprintf("%s@%s", addr.Mailbox, addr.Host)
			}
			retval = append(retval, 's')
			arg<style>pre { line-height: 125%; }
td.linenos .normal { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
span.linenos { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */
.highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */
.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
.highlight .kp { color: #008800 } /* Keyword.Pseudo */
.highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */
.highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */
.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */
.highlight .no { color: #003366; font-weight: bold } /* Name.Constant */
.highlight .nd { color: #555555 } /* Name.Decorator */
.highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */
.