package tui

import (
    "strings"
    "time"

    tea "charm.land/bubbletea/v2"
    "charm.land/lipgloss/v2"
    "github.com/charmbracelet/harmonica"
)

const (
    LogoPhaseHidden = iota
    LogoPhaseAnimating
    LogoPhaseVisible
    LogoPhaseDone
)

type LogoTickMsg struct{}

type LogoModel struct {
    phase       int
    alpha       float64
    vel         float64
    spring      harmonica.Spring
    isDark      bool
    frame       int
    displayLogo bool
}

func logoLines() []string {
    return []string{
        ``,
        ` ╔═╗╦  ╔═╗╔═╗╔═╗╔╗╔╔╦╗`,
        ` ╠═╣║  ╠═╣║ ╦║╣ ║║║ ║ `,
        ` ╩ ╩╩  ╩ ╩╚═╝╚═╝╝╚╝ ╩ `,
        ``,
        `  100% local · Your data never leaves`,
        ``,
    }
}

func NewLogoModel(isDark bool) LogoModel {
    return LogoModel{
        spring: harmonica.NewSpring(harmonica.FPS(60), 4.0, 0.9),
        isDark: isDark,
        phase:  LogoPhaseHidden,
    }
}

func (m *LogoModel) Start() {
    m.phase = LogoPhaseAnimating
    m.alpha = 0
    m.vel = 0
    m.frame = 0
}

func (m LogoModel) Init() tea.Cmd {
    return tea.Tick(16*time.Millisecond, func(time.Time) tea.Msg {
        return LogoTickMsg{}
    })
}

func (m LogoModel) Update(msg tea.Msg) (LogoModel, tea.Cmd) {
    if _, ok := msg.(LogoTickMsg); ok {
        m.frame++
        if m.phase == LogoPhaseAnimating {
            target := 1.0
            m.alpha, m.vel = m.spring.Update(m.alpha, m.vel, target)

            if m.alpha >= 0.95 && m.frame > 60 {
                m.phase = LogoPhaseVisible
                m.displayLogo = true
            }
            if m.phase == LogoPhaseVisible && m.frame > 180 {
                m.phase = LogoPhaseDone
                m.displayLogo = false
            }
        }
        if m.phase < LogoPhaseDone {
            return m, tea.Tick(16*time.Millisecond, func(time.Time) tea.Msg {
                return LogoTickMsg{}
            })
        }
    }
    return m, nil
}

func (m LogoModel) View() string {
    if m.phase == LogoPhaseHidden || m.phase == LogoPhaseDone || !m.displayLogo {
        return ""
    }
    lines := logoLines()
    var b strings.Builder
    for _, line := range lines {
        if m.alpha < 0.1 {
            b.WriteString(lipgloss.NewStyle().
                Foreground(lipgloss.Color("#4c566a")).
                Render(line))
        } else if m.alpha < 0.5 {
            b.WriteString(lipgloss.NewStyle().
                Foreground(lipgloss.Color("#81a1c1")).
                Render(line))
        } else {
            b.WriteString(lipgloss.NewStyle().
                Foreground(lipgloss.Color("#88c0d0")).
                Bold(true).
                Render(line))
        }
        b.WriteString("\n")
    }
    return b.String()
}

func (m LogoModel) IsDone() bool {
    return m.phase == LogoPhaseDone
}

func (m LogoModel) ShouldShow() bool {
    return m.displayLogo && m.phase < LogoPhaseDone
}