// Package modules implements all the modules.
// Copyright (C) 2022 Kevin Lyda <kevin@lyda.ie>
package modules

import (
	"fmt"
	"math"
	"time"

	"github.com/distatus/battery"
)

type battTS struct {
	charge float64
	point  time.Time
}

// BatteryMod module parameters for the battery module.
type BatteryMod struct {
	name       string
	onclick    string
	battStats  []battTS
	Battery    int    `yaml:"battery"`
	StatusEmp  string `yaml:"status-chr"`
	StatusChr  string `yaml:"status-chr"`
	StatusBat  string `yaml:"status-bat"`
	StatusUnk  string `yaml:"status-unk"`
	StatusFull string `yaml:"status-full"`
	OnError    string `yaml:"on-error"`
	ColorOK    string `yaml:"color-ok"`
	Color20    string `yaml:"color-20"`
	Color10    string `yaml:"color-10"`
	ColorError string `yaml:"color-error"`
}

// NewBattery creates a BatteryMod instance.
func NewBattery(m *Module) *BatteryMod {
	b := &BatteryMod{
		name:    m.Name,
		onclick: m.OnClick,
	}
	if b.name == "" {
		b.name = "battery"
	}
	return b
}

// SetDefaults sets defaults.
func (b *BatteryMod) SetDefaults() {
	if b.StatusEmp == "" {
		b.StatusEmp = "---"
	}
	if b.StatusChr == "" {
		b.StatusChr = "CHR"
	}
	if b.StatusBat == "" {
		b.StatusBat = "BAT"
	}
	if b.StatusUnk == "" {
		b.StatusUnk = "UNK"
	}
	if b.StatusFull == "" {
		b.StatusFull = "FULL"
	}
	if b.OnError == "" {
		b.OnError = "No BAT"
	}
	if b.ColorOK == "" {
		b.ColorOK = "#11ff11"
	}
	if b.Color20 == "" {
		b.Color20 = "#ffa500"
	}
	if b.Color10 == "" {
		b.Color10 = "#ffff00"
	}
	if b.ColorError == "" {
		b.ColorError = "#ff1111"
	}
}

// Name returns the name setting for the module.
func (b *BatteryMod) Name() string {
	return b.name
}

// OnClick returns the on-click setting for the module.
func (b *BatteryMod) OnClick() string {
	return b.onclick
}

// Render renders the module.
func (b *BatteryMod) Render() string {
	// TODO: Alerting.

	now := time.Now()
	batt, err := battery.Get(b.Battery)
	if err != nil {
		return fmt.Sprintf(`{"name": "%s", "full_text": "%s", "color": "%s"}`, b.name, b.OnError, b.ColorError)
	}
	left := "(?)"
	if len(b.battStats) >= 1 {
		delta := now.Sub(b.battStats[0].point)
		if delta >= (60 * time.Second) {
			discharge := math.Abs(batt.Current - b.battStats[0].charge)
			if discharge > 0 {
				timeLeft := time.Duration((batt.Full-batt.Current)/discharge) * delta
				left = fmt.Sprintf("%dh%dm", int64(timeLeft.Hours()), int64(timeLeft.Minutes()-(timeLeft.Hours()*60)))
				b.battStats = b.battStats[1:]
			} else {
				left = "0h0m"
			}
		}
	}
	b.battStats = append(b.battStats, battTS{
		charge: batt.Current,
		point:  now,
	})

	states := [...]string{
		battery.Unknown:     b.StatusUnk,
		battery.Empty:       b.StatusEmp,
		battery.Full:        b.StatusFull,
		battery.Charging:    b.StatusChr,
		battery.Discharging: b.StatusBat,
	}

	color := b.ColorOK
	percent := 100 * (batt.Current / batt.Design)
	if percent < 20 {
		color = b.Color20
	}
	if percent < 10 {
		color = b.Color10
	}

	if b.Battery > 0 {
		return fmt.Sprintf(`{"name": "%s", "full_text": "%s%d %.1f%% %s", "color": "%s"}`, b.name, states[batt.State], b.Battery, percent, left, color)
	}
	return fmt.Sprintf(`{"name": "%s", "full_text": "%s %.1f%% %s", "color": "%s"}`, b.name, states[batt.State], percent, left, color)
}