package main

import "errors"

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

//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"
	//Python writes the virtual env name
	Python SegmentType = "python"
	//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"
	//Node writes which node version is currently active
	Node SegmentType = "node"
	//Os write os specific icon
	Os SegmentType = "os"
	//EnvVar writes the content of an environment variable
	EnvVar SegmentType = "envvar"
	//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 {
	segment.active = segment.writer.enabled()
	return segment.active
}

func (segment *Segment) getValue(property Property, defaultValue string) string {
	if value, ok := segment.Properties[property]; ok {
		return parseString(value, defaultValue)
	}
	return defaultValue
}

func (segment *Segment) hasValue(property Property, match string) bool {
	if value, ok := segment.Properties[property]; ok {
		list := parseStringArray(value)
		for _, element := range list {
			if element == match {
				return true
			}
		}
		return false
	}
	return false
}

func (segment *Segment) mapSegmentWithWriter(env environmentInfo) error {
	functions := map[SegmentType]SegmentWriter{
		Session:   &session{},
		Path:      &path{},
		Git:       &git{},
		Exit:      &exit{},
		Python:    &python{},
		Root:      &root{},
		Text:      &text{},
		Time:      &tempus{},
		Cmd:       &command{},
		Battery:   &batt{},
		Spotify:   &spotify{},
		ShellInfo: &shell{},
		Node:      &node{},
		Os:        &osInfo{},
		EnvVar:    &envvar{},
	}
	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
		segment.props = props
		return nil
	}
	return errors.New("Unable to map writer")
}