package main

import "errors"

//Segment represent a single segment and it's configuration
type Segment struct {
	Type            SegmentType              `json:"type"`
	Style           SegmentStyle             `json:"style"`
	Foreground      string                   `json:"foreground"`
	Background      string                   `json:"background"`
	LeadingDiamond  string                   `json:"leading_diamond"`
	TrailingDiamond string                   `json:"trailing_diamond"`
	Properties      map[Property]interface{} `json:"properties"`
	writer          SegmentWriter
}

//SegmentWriter is the interface used to define what and if to write to the prompt
type SegmentWriter interface {
	enabled() bool
	string() string
	init(props *properties, env environmentInfo)
}

//SegmentStyle the syle of segment, for more information, see the constants
type SegmentStyle string

//SegmentType the type of segment, for more information, see the constants
type SegmentType string

const (
	//Session represents the user info segment
	Session SegmentType = "session"
	//Path represents the current path segment
	Path SegmentType = "path"
	//Git represents the git status and information
	Git SegmentType = "git"
	//Exit writes the last exit code
	Exit SegmentType = "exit"
	//Venv writes the virtual env name
	Venv SegmentType = "virtualenv"
	//Root writes root symbol
	Root SegmentType = "root"
	//Time writes the current timestamp
	Time SegmentType = "time"
	//Text writes a text
	Text SegmentType = "text"
	//Cmd writes the output of a shell command
	Cmd SegmentType = "command"
	//Battery writes the battery percentage
	Battery SegmentType = "battery"
	//Spotify writes the Spotify status for Mac
	Spotify SegmentType = "spotify"
	//ShellInfo writes which shell we're currently in
	ShellInfo SegmentType = "shell"
	//NVM writes which node version is currently active using nvm
	NVM SegmentType = "nvm"
	//Powerline writes it Powerline style
	Powerline SegmentStyle = "powerline"
	//Plain writes it without ornaments
	Plain SegmentStyle = "plain"
	//Diamond writes the prompt shaped with a leading and trailing symbol
	Diamond SegmentStyle = "diamond"
)

func (segment *Segment) string() string {
	return segment.writer.string()
}

func (segment *Segment) enabled() bool {
	return segment.writer.enabled()
}

func (segment *Segment) mapSegmentWithWriter(env environmentInfo) (*properties, error) {
	functions := map[SegmentType]SegmentWriter{
		Session:   &session{},
		Path:      &path{},
		Git:       &git{},
		Exit:      &exit{},
		Venv:      &venv{},
		Root:      &root{},
		Text:      &text{},
		Time:      &tempus{},
		Cmd:       &command{},
		Battery:   &batt{},
		Spotify:   &spotify{},
		ShellInfo: &shell{},
		NVM:       &nvm{},
	}
	if writer, ok := functions[segment.Type]; ok {
		props := &properties{
			values:     segment.Properties,
			foreground: segment.Foreground,
			background: segment.Background,
		}
		writer.init(props, env)
		segment.writer = writer
		return props, nil
	}
	return nil, errors.New("Unable to map writer")
}