package tui

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/cobr-ai/apex/internal/intake"
	"github.com/cobr-ai/apex/internal/store"

	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
)

const (
	TabIntake    = "Intake"
	TabScan      = "Scan"
	TabEvaluate  = "Evaluate"
	TabTracker   = "Tracker"
	TabPipeline  = "Pipeline"
	TabReports   = "Reports"
	TabSettings  = "Settings"
)

type tabbedModel interface {
	tea.Model
	Resize(width, height int)
}

type App struct {
	activeTab string
	cursorTab int
	tabs      []string
	models    map[string]tea.Model
	db        *store.DB
	dims      layoutDims
	showHelp  bool
	errBanner string
}

func NewApp() *App {
	app := &App{
		activeTab: TabIntake,
		tabs:      []string{TabIntake, TabScan, TabEvaluate, TabTracker, TabPipeline, TabReports, TabSettings},
		models:    make(map[string]tea.Model),
	}

	homeDir, err := os.UserHomeDir()
	if err != nil {
		homeDir = "/tmp"
	}
	dbPath := filepath.Join(homeDir, ".apex", "apex.db")
	os.MkdirAll(filepath.Dir(dbPath), 0755)

	db, err := store.NewDB(dbPath)
	if err != nil {
		app.errBanner = fmt.Sprintf("database init failed: %v", err)
		app.models[TabIntake] = NewPlaceholder("Intake — database unavailable")
		app.models[TabScan] = NewPlaceholder("Scan — database unavailable")
		app.models[TabEvaluate] = NewPlaceholder("Evaluate — database unavailable")
		app.models[TabTracker] = NewPlaceholder("Tracker — database unavailable")
		app.models[TabPipeline] = NewPlaceholder("Pipeline — database unavailable")
		app.models[TabReports] = NewPlaceholder("Reports — database unavailable")
		app.models[TabSettings] = NewPlaceholder("Settings — database unavailable")
		return app
	}
	app.db = db

	manager := intake.NewManager(db.Conn())
	app.models[TabIntake] = NewIntakeModel(manager)

	scanCfgPath := filepath.Join(findRepoRoot(), "internal", "scan", "adapters.yaml")
	app.models[TabScan] = NewScanModel(scanCfgPath, app.db.Conn())

	cvPath := filepath.Join(homeDir, ".apex", "cv.md")
	app.models[TabEvaluate] = NewEvalModel(app.db.Conn(), cvPath)

	app.models[TabTracker] = NewTrackerModel(app.db.Conn())
	app.models[TabPipeline] = NewPipelineModel(app.db.Conn())
	app.models[TabReports] = NewReportsModel(app.db.Conn())
	app.models[TabSettings] = NewSettingsModel(app.db.Conn(), scanCfgPath)

	return app
}

func (a *App) Run() error {
	p := tea.NewProgram(a, tea.WithAltScreen())
	_, err := p.Run()
	return err
}

func (a *App) Init() tea.Cmd {
	cmds := []tea.Cmd{}
	for _, m := range a.models {
		if m != nil {
			if c := m.Init(); c != nil {
				cmds = append(cmds, c)
			}
		}
	}
	return tea.Batch(cmds...)
}

func (a *App) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		a.dims = computeLayout(msg.Width, msg.Height)
		for _, name := range a.tabs {
			if tm, ok := a.models[name].(tabbedModel); ok {
				tm.Resize(a.dims.contentW, a.dims.contentH)
			}
		}
	case tea.KeyMsg:
		key := msg.String()
		if a.showHelp {
			switch key {
			case "?", "esc", "q":
				a.showHelp = false
				return a, nil
			}
			return a, nil
		}
		switch key {
		case "ctrl+c":
			return a, tea.Quit
		case "?":
			a.showHelp = true
			return a, nil
		case "tab", "down":
			a.cursorTab = (a.cursorTab + 1) % len(a.tabs)
			a.activeTab = a.tabs[a.cursorTab]
			return a, nil
		case "shift+tab", "up":
			a.cursorTab = (a.cursorTab - 1 + len(a.tabs)) % len(a.tabs)
			a.activeTab = a.tabs[a.cursorTab]
			return a, nil
		}
	}

	model, cmd := a.models[a.activeTab].Update(msg)
	a.models[a.activeTab] = model
	return a, cmd
}

func (a *App) View() string {
	if a.dims.termW == 0 {
		return "initializing…"
	}
	title := StyleTitle.Render("apex") + " " + StyleSubtitle.Render("// job-search platform")
	sidebar := a.renderSidebar()
	content := a.renderContent()
	body := lipgloss.JoinHorizontal(lipgloss.Top, sidebar, content)
	footer := a.renderFooter()
	view := lipgloss.JoinVertical(lipgloss.Left, title, body, footer)
	if a.showHelp {
		overlay := a.renderHelp()
		return placeOverlay(view, overlay, a.dims.termW, a.dims.termH)
	}
	return view
}

func (a *App) renderSidebar() string {
	var items []string
	for _, t := range a.tabs {
		if t == a.activeTab {
			items = append(items, StyleSidebarActive.Render("▌ "+t))
		} else {
			items = append(items, StyleSidebarItem.Render("  "+t))
		}
	}
	inner := lipgloss.JoinVertical(lipgloss.Left, items...)
	return StyleSidebarBox.
		Width(sidebarWidth).
		Height(a.dims.sidebarH).
		Render(inner)
}

func (a *App) renderContent() string {
	m := a.models[a.activeTab]
	body := ""
	if m != nil {
		body = m.View()
	}
	return StyleContentBox.
		Width(a.dims.contentW).
		Height(a.dims.contentH).
		Render(body)
}

func (a *App) renderFooter() string {
	parts := []string{}
	add := func(k, d string) {
		parts = append(parts, StyleKey.Render(k)+" "+StyleKeyDesc.Render(d))
	}
	add("↑/↓", "tab")
	add("j/k", "row")
	add("?", "help")
	add("q", "quit")
	if bindings, ok := a.activeTabBindings(); ok {
		parts = append(parts, StyleKeyDesc.Render("│"))
		for _, kb := range bindings {
			add(kb.Key, kb.Desc)
		}
	}
	line := strings.Join(parts, "  ")
	if a.errBanner != "" {
		line = StyleStatusErr.Render(a.errBanner) + "  " + line
	}
	return StyleFooter.Render(line)
}

func placeOverlay(bg, fg string, w, h int) string {
	bgLines := strings.Split(bg, "\n")
	fgLines := strings.Split(fg, "\n")
	fgH := len(fgLines)
	fgW := 0
	for _, l := range fgLines {
		if ll := lipgloss.Width(l); ll > fgW {
			fgW = ll
		}
	}
	top := (h - fgH) / 2
	left := (w - fgW) / 2
	if top < 0 {
		top = 0
	}
	if left < 0 {
		left = 0
	}
	out := make([]string, len(bgLines))
	copy(out, bgLines)
	for i, fl := range fgLines {
		y := top + i
		if y < 0 || y >= len(out) {
			continue
		}
		padded := padAnsiLeft(out[y], left) + fl
		out[y] = padded
	}
	return strings.Join(out, "\n")
}

func padAnsiLeft(s string, col int) string {
	w := lipgloss.Width(s)
	if w >= col {
		return truncDisplay(s, col)
	}
	return s + strings.Repeat(" ", col-w)
}

func truncDisplay(s string, n int) string {
	if lipgloss.Width(s) <= n {
		return s
	}
	runes := []rune(s)
	buf := strings.Builder{}
	width := 0
	for _, r := range runes {
		cell := 1
		if r > 0x2e80 {
			cell = 2
		}
		if width+cell > n {
			break
		}
		buf.WriteRune(r)
		width += cell
	}
	return buf.String()
}