package main

import (
	"context"
	"time"

	tea "github.com/charmbracelet/bubbletea"
)

// modelConfig is the static configuration the dashboard needs beyond the
// scanner.
type modelConfig struct {
	Interval time.Duration
	Title    string
	BaseURL  string
}

// tickMsg drives the clock and the scan countdown.
type tickMsg time.Time

// snapshotMsg carries a finished scan back into the model.
type snapshotMsg snapshot

type model struct {
	sc   *scanner
	cfg  modelConfig
	snap snapshot
	// scanErr is kept separately so a failed refresh does not erase the last
	// successful data from the display.
	scanErr error

	scanning   bool
	nextScanAt time.Time

	width, height int
	ready         bool
}

func newModel(sc *scanner, cfg modelConfig) model {
	return model{sc: sc, cfg: cfg, nextScanAt: time.Now()}
}

func (m model) Init() tea.Cmd {
	return tea.Batch(tickClock(), m.scanCmd())
}

func tickClock() tea.Cmd {
	return tea.Tick(time.Second, func(t time.Time) tea.Msg { return tickMsg(t) })
}

func (m *model) scanCmd() tea.Cmd {
	sc := m.sc
	return func() tea.Msg { return snapshotMsg(sc.Scan(context.Background(), time.Now())) }
}

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		m.width, m.height, m.ready = msg.Width, msg.Height, true
		return m, nil

	case tea.KeyMsg:
		switch msg.String() {
		case "q", "esc", "ctrl+c":
			return m, tea.Quit
		case "r":
			if !m.scanning {
				m.scanning = true
				return m, m.scanCmd()
			}
			return m, nil
		}
		return m, nil

	case tickMsg:
		now := time.Time(msg)
		cmd := tickClock()
		if !m.scanning && !now.Before(m.nextScanAt) {
			m.scanning = true
			return m, tea.Batch(cmd, m.scanCmd())
		}
		return m, cmd

	case snapshotMsg:
		snap := snapshot(msg)
		if snap.Err != nil {
			m.scanErr = snap.Err
		} else {
			m.snap = snap
			m.scanErr = nil
		}
		m.scanning = false
		m.nextScanAt = time.Now().Add(m.cfg.Interval)
		return m, nil
	}
	return m, nil
}

func (m model) View() string {
	return renderSnapshot(m.snap, snapshotOptions{
		Width: m.width, Height: m.height, Title: m.cfg.Title, BaseURL: m.cfg.BaseURL,
		Scanning: m.scanning, NextScanAt: m.nextScanAt, Now: time.Now(), ScanError: m.scanErr,
	})
}