package page

import (
	"fmt"
	"math"

	"github.com/go-gl/gl/v3.3-core/gl"
	"github.com/go-gl/mathgl/mgl32"
	"github.com/veandco/go-sdl2/sdl"
	"rhemawavetech.com/rhemawave/internal/colors"
	"rhemawavetech.com/rhemawave/internal/db"
	"rhemawavetech.com/rhemawave/internal/fontManager"
	"rhemawavetech.com/rhemawave/internal/logger"
	"rhemawavetech.com/rhemawave/internal/mixer"
	"rhemawavetech.com/rhemawave/internal/shaderManager"
)

// focusToggle is the sentinel focusState value meaning the audio on/off toggle
// row has keyboard focus. Device indices (0..n-1) are used for everything below.
const focusToggle = -1

// AudioFileList is kept as the canonical seed data for the audio_files table.
// Track selection UI no longer lives on this page, but other parts of the
// app still read these rows from the database.
var AudioFileList = []db.AudioFile{
	{ID: 14, Name: "Original Audio", Path: "OriginalAudio.wav", Selected: false, Order: 1},
	{ID: 1, Name: "174 Hz", Path: "174Hz.wav", Selected: false, Order: 2},
	{ID: 2, Name: "396 Hz", Path: "396Hz.wav", Selected: false, Order: 3},
	{ID: 3, Name: "417 Hz", Path: "417Hz.wav", Selected: false, Order: 4},
	{ID: 4, Name: "432 Hz", Path: "432Hz.wav", Selected: false, Order: 5},
	{ID: 5, Name: "639 Hz", Path: "639Hz.wav", Selected: false, Order: 6},
	{ID: 6, Name: "741 Hz", Path: "741Hz.wav", Selected: false, Order: 7},
	{ID: 7, Name: "852 Hz", Path: "852Hz.wav", Selected: false, Order: 8},
	{ID: 8, Name: "963 Hz", Path: "963Hz.wav", Selected: false, Order: 9},
	{ID: 9, Name: "1111 Hz", Path: "1111Hz.wav", Selected: false, Order: 10},
	{ID: 10, Name: "14 Hz Binaural Beat", Path: "14Hz_Binaural.wav", Selected: false, Order: 11},
	{ID: 11, Name: "40 Hz Binaural Beat", Path: "40Hz_Binaural.wav", Selected: false, Order: 12},
	{ID: 12, Name: "Alpha Waves", Path: "AlphaWaves.wav", Selected: false, Order: 13},
	{ID: 13, Name: "Pineal Gland", Path: "PinealGland.wav", Selected: false, Order: 14},
}

const triangleSize = float32(16)

type AudioDevice struct {
	Label string
	ID    uint32
	index int
}

type AudioOptions struct {
	// Page Attributes
	Base
	font        *fontManager.FontEntry
	textShader  *shaderManager.Shader
	solidShader *shaderManager.Shader
	CfgPtr      *db.AppConfig

	// Page Textures
	title  StringItem
	prompt StringItem

	// Layout
	verticalMargin int32
	ItemScale      float32

	// Audio toggle
	AudioStatusToggle StringItem

	// Audio Devices
	activeDeviceIndex   int
	NumAudioDevices     int
	AudioDevices        []AudioDevice
	AudioDeviceTextures []StringItem

	// Volume row
	VolumeLabel   StringItem
	volumePercent StringItem
	volumeBarX    int32
	volumeBarY    int32
	volumeBarW    int32
	volumeBarH    int32

	// Triangle cursor
	triVAO      uint32
	triVBO      uint32
	triX        float32
	triCenterY  float32
	spinElapsed float32

	// Focus: focusToggle (-1) = toggle row, 0..n-1 = device at that index
	focusState int
}

// ── Init ──────────────────────────────────────────────────────────────────────

func (p *AudioOptions) Init(ctx *PageCtx) error {
	var err error
	p.verticalMargin = int32(20)
	p.focusState = focusToggle

	// Font
	fm := fontManager.Get()
	font, ok := fm.GetFont("SpaceMonoNerdFont-Regular")
	if !ok {
		return fmt.Errorf("failed to get font: %w", sdl.GetError())
	}
	p.font = font

	// Shaders
	sm := shaderManager.Get()
	p.textShader, ok = sm.Get("text")
	if !ok {
		return fmt.Errorf("failed to get text shader: %w", sdl.GetError())
	}
	p.solidShader, ok = sm.Get("solid_color")
	if !ok {
		return fmt.Errorf("failed to get solid_color shader: %w", sdl.GetError())
	}

	if err = p.Base.Init(ctx); err != nil {
		return fmt.Errorf("base init failed: %w", err)
	}

	config, err := db.GetConfig(p.Context.DbPtr)
	if err != nil {
		panic(err)
	}

	baseFontSize := config.StandardFontSize
	titleScale := float32(64) / float32(baseFontSize)
	p.ItemScale = float32(32) / float32(baseFontSize)

	// Title
	p.title, err = NewStringItem("Audio Options", p.font, colors.White)
	if err != nil {
		return fmt.Errorf("creating title: %w", err)
	}
	p.title.Scale(titleScale)

	// Prompt
	p.prompt, err = NewStringItem(
		"Enter to select  --  Up/Down to navigate  --  Left/Right to change volume  --  Backspace to go back",
		p.font, colors.White,
	)
	if err != nil {
		return fmt.Errorf("creating prompt: %w", err)
	}
	p.prompt.Scale(p.ItemScale)

	// Volume row
	p.VolumeLabel, err = NewStringItem("Volume", p.font, colors.White)
	if err != nil {
		return fmt.Errorf("creating volume label: %w", err)
	}
	p.VolumeLabel.Scale(p.ItemScale)
	if err = p.CreateVolumePercentItem(); err != nil {
		logger.Error("failed to create VolumePercentItem in AudioOptions.Init()")
	}

	// Audio toggle
	if err = p.CreateAudioStatusItem(); err != nil {
		logger.Error("failed to create AudioStatusItem in AudioOptions.Init()")
	}

	// Audio output devices
	if err = p.GetAudioDevices(); err != nil {
		logger.Error("failed to enumerate audio devices: %v", err)
	}

	// Set active device index based on mixer's current device
	currentName := mixer.CurrentDevice()
	config, err = db.GetConfig(p.Context.DbPtr)
	if err != nil {
		panic(err)
	}
	p.activeDeviceIndex = -1 // default to not found
	for i, dev := range p.AudioDevices {
		if dev.Label == currentName {
			p.activeDeviceIndex = i
			break
		}
	}
	// If not found and current device is default (""), check saved config
	if p.activeDeviceIndex == -1 && currentName == "" && config.SelectedAudioDevice == "default" {
		// Default device is selected - first device in SDL list is typically the default
		if len(p.AudioDevices) > 0 {
			p.activeDeviceIndex = 0
		}
	}

	// Make sure the audio_files table is populated.
	if err = p.seedAudioFiles(); err != nil {
		logger.Error("failed to seed audio files: %v", err)
	}

	// Triangle cursor VAO/VBO — stride is vec2 only, no tex coords
	triVerts := []float32{
		0.5, 0.0,
		-0.5, 0.5,
		-0.5, -0.5,
	}
	gl.GenVertexArrays(1, &p.triVAO)
	gl.GenBuffers(1, &p.triVBO)
	gl.BindVertexArray(p.triVAO)
	gl.BindBuffer(gl.ARRAY_BUFFER, p.triVBO)
	gl.BufferData(gl.ARRAY_BUFFER, len(triVerts)*4, gl.Ptr(triVerts), gl.STATIC_DRAW)
	gl.EnableVertexAttribArray(0)
	gl.VertexAttribPointerWithOffset(0, 2, gl.FLOAT, false, 2*4, 0)
	gl.BindBuffer(gl.ARRAY_BUFFER, 0)
	gl.BindVertexArray(0)

	p.layout()
	return nil
}

// seedAudioFiles ensures the audio_files table has its default rows.
func (p *AudioOptions) seedAudioFiles() error {
	var existing []db.AudioFile
	if err := p.Context.DbPtr.Find(&existing).Error; err != nil {
		return err
	}
	if len(existing) == 0 {
		return p.Context.DbPtr.Save(&AudioFileList).Error
	}
	return nil
}

// ── Audio status toggle ───────────────────────────────────────────────────────

func (p *AudioOptions) CreateAudioStatusItem() error {
	config, err := db.GetConfig(p.Context.DbPtr)
	if err != nil {
		panic(err)
	}
	on := config.AudioEnabled
	statusString := "Turn Audio On"
	color := colors.Green
	if on {
		statusString = "Turn Audio Off"
		color = colors.Red
	}
	item, err := NewStringItem(statusString, p.font, color)
	if err != nil {
		return fmt.Errorf("failed to create '%s' string item: %v", statusString, err)
	}
	item.Scale(p.ItemScale)
	p.AudioStatusToggle = item
	return nil
}

// ── Audio Output Devices ──────────────────────────────────────────────────────

func (p *AudioOptions) GetAudioDevices() error {
	numAudioDevices := sdl.GetNumAudioDevices(false)
	if numAudioDevices == 0 {
		return nil
	}

	// Pre-allocate with zero length so append doesn't produce leading zero-value
	// elements (the old code used make([]AudioDevice, n) then appended, which
	// doubled the slice length with n zero-value entries at the front).
	audioDevices := make([]AudioDevice, 0, numAudioDevices)
	for i := range numAudioDevices {
		label := sdl.GetAudioDeviceName(i, false)
		audioDevices = append(audioDevices, AudioDevice{Label: label, ID: uint32(i)})
	}
	p.AudioDevices = audioDevices

	for i := range audioDevices {
		item, err := NewStringItem(p.AudioDevices[i].Label, p.font, colors.White)
		if err != nil {
			return err
		}
		item.Scale(p.ItemScale)
		p.AudioDeviceTextures = append(p.AudioDeviceTextures, item)
	}
	p.NumAudioDevices = numAudioDevices
	return nil
}

// SelectAudioDevice is called when the user confirms a device from the list.
// The device-switching implementation goes here; for now we just log the choice.
func (p *AudioOptions) SelectAudioDevice(deviceIndex int) error {
	if deviceIndex < 0 || deviceIndex >= len(p.AudioDevices) {
		return fmt.Errorf("invalid device index: %d", deviceIndex)
	}
	device := p.AudioDevices[deviceIndex]

	config, err := db.GetConfig(p.Context.DbPtr)
	if err != nil {
		return fmt.Errorf("failed to get config for device switch: %w", err)
	}

	if err := mixer.SwitchDevice(device.Label, config); err != nil {
		return fmt.Errorf("failed to switch to device %s: %w", device.Label, err)
	}

	// Persist the selected device to the database
	config.SelectedAudioDevice = device.Label
	if err := p.Context.DbPtr.Save(config).Error; err != nil {
		logger.Error("failed to persist device selection: %v", err)
	}

	p.activeDeviceIndex = deviceIndex
	return nil
}

// ── Volume ────────────────────────────────────────────────────────────────────

func (p *AudioOptions) CreateVolumePercentItem() error {
	if p.volumePercent.ID != 0 {
		gl.DeleteTextures(1, &p.volumePercent.ID)
	}
	config, err := db.GetConfig(p.Context.DbPtr)
	if err != nil {
		panic(err)
	}
	pct := int(config.SavedVolume * 100)
	item, err := NewStringItem(fmt.Sprintf("%d%%", pct), p.font, colors.White)
	if err != nil {
		return fmt.Errorf("failed to create volume percent item: %v", err)
	}
	item.Scale(p.ItemScale)
	p.volumePercent = item
	return nil
}

func (p *AudioOptions) UpdateVolume(level int) {
	config, err := db.GetConfig(p.Context.DbPtr)
	if err != nil {
		panic(err)
	}
	newVol := mixer.ConvertVolume(level) + config.SavedVolume
	if newVol < 0.0 || newVol > 1.0 {
		return
	}
	if newVol > .99 {
		newVol = 1.0
	}
	config.SavedVolume = newVol
	p.Context.DbPtr.Save(&config)
	if err := mixer.SetAllSinkVolumes(newVol); err != nil {
		logger.Error("Error setting allSinkVolumes: %v", err)
	}
	if err := p.CreateVolumePercentItem(); err != nil {
		logger.Error("failed to refresh volume percent item: %v", err)
	}
	gap := int32(12)
	p.volumePercent.X = p.volumeBarX + p.volumeBarW + gap
	p.volumePercent.Y = p.volumeBarY + (p.volumeBarH-p.volumePercent.H)/2
}

// ── Layout ────────────────────────────────────────────────────────────────────

func (p *AudioOptions) layout() {
	config, err := db.GetConfig(p.Context.DbPtr)
	if err != nil {
		panic(err)
	}

	// Title
	p.title.X = p.ScreenCenterX - p.title.W/2
	p.title.Y = p.ScreenHeight - p.title.H - p.verticalMargin*2

	// Prompt
	p.prompt.X = p.ScreenCenterX - p.prompt.W/2
	p.prompt.Y = p.title.Y - p.verticalMargin - p.prompt.H

	// Volume row
	barH := int32(float32(config.StandardFontSize) * p.ItemScale)
	barW := int32(float32(p.ScreenWidth) * 0.30)
	barX := p.ScreenCenterX - barW/2
	barY := p.prompt.Y - p.verticalMargin*2 - barH

	p.volumeBarX = barX
	p.volumeBarY = barY
	p.volumeBarW = barW
	p.volumeBarH = barH

	p.VolumeLabel.X = barX - p.VolumeLabel.W - 20
	p.VolumeLabel.Y = barY + (barH-p.VolumeLabel.H)/2

	gap := int32(12)
	p.volumePercent.X = barX + barW + gap
	p.volumePercent.Y = barY + (barH-p.volumePercent.H)/2

	// Audio toggle — centred below the volume row
	p.AudioStatusToggle.X = p.ScreenCenterX - p.AudioStatusToggle.W/2
	p.AudioStatusToggle.Y = barY - p.verticalMargin*3 - p.AudioStatusToggle.H

	// Device list — each item centred and stacked below the toggle
	nextY := p.AudioStatusToggle.Y - p.verticalMargin
	for i := range p.AudioDeviceTextures {
		item := &p.AudioDeviceTextures[i]
		item.X = p.ScreenCenterX - item.W/2
		item.Y = nextY - item.H
		nextY = item.Y - p.verticalMargin
	}

	// Reposition the triangle cursor for whatever row currently has focus
	p.updateCursorPosition()
}

// updateCursorPosition moves triX / triCenterY to sit just left of the
// focused row. Call this any time focusState changes or layout() reruns.
func (p *AudioOptions) updateCursorPosition() {
	cursorGap := int32(12)

	var item *StringItem
	switch {
	case p.focusState == focusToggle:
		item = &p.AudioStatusToggle
	case p.focusState >= 0 && p.focusState < len(p.AudioDeviceTextures):
		item = &p.AudioDeviceTextures[p.focusState]
	default:
		return
	}

	p.triX = float32(item.X) - triangleSize - float32(cursorGap)
	p.triCenterY = float32(item.Y) + float32(item.H)/2
}

// ── Toggle ────────────────────────────────────────────────────────────────────

func (p *AudioOptions) ToggleAudio() {
	config, err := db.GetConfig(p.Context.DbPtr)
	if err != nil {
		logger.Error("panic! Cannot query database for configuration")
		panic(err)
	}
	config.AudioEnabled = !config.AudioEnabled
	p.Context.DbPtr.Save(config)
	p.CreateAudioStatusItem()
	p.layout()
}

// ── Events ────────────────────────────────────────────────────────────────────

func (p *AudioOptions) HandleEvent(event *sdl.Event) error {
	e, ok := (*event).(*sdl.KeyboardEvent)
	if !ok || e.Type != sdl.KEYDOWN {
		return nil
	}

	switch e.Keysym.Sym {
	case sdl.K_RETURN:
		if p.focusState == focusToggle {
			p.ToggleAudio()
		} else if p.focusState >= 0 && p.focusState < len(p.AudioDevices) {
			if err := p.SelectAudioDevice(p.focusState); err != nil {
				logger.Error("SelectAudioDevice: %v", err)
			}
		}

	case sdl.K_DOWN:
		if p.focusState == focusToggle {
			if len(p.AudioDeviceTextures) > 0 {
				p.focusState = 0
				p.updateCursorPosition()
			}
		} else if p.focusState < len(p.AudioDeviceTextures)-1 {
			p.focusState++
			p.updateCursorPosition()
		}

	case sdl.K_UP:
		if p.focusState == 0 {
			p.focusState = focusToggle
			p.updateCursorPosition()
		} else if p.focusState > 0 {
			p.focusState--
			p.updateCursorPosition()
		}

	case sdl.K_RIGHT:
		p.UpdateVolume(10)

	case sdl.K_LEFT:
		p.UpdateVolume(-10)

	case sdl.K_BACKSPACE:
		p.Context.NavigateTo(SETTINGS)
	}

	return nil
}

// ── Update ────────────────────────────────────────────────────────────────────

func (p *AudioOptions) Update(dt float32) error {
	p.spinElapsed += dt
	if p.spinElapsed >= 1.0 {
		p.spinElapsed -= 1.0
	}
	return nil
}

// ── Render helpers ────────────────────────────────────────────────────────────

func (p *AudioOptions) renderVolumeBar() error {
	config, err := db.GetConfig(p.Context.DbPtr)
	if err != nil {
		panic(err)
	}
	vol := config.SavedVolume

	fillW := float32(p.volumeBarW) * float32(vol)
	if fillW > 0 {
		if err := p.RenderSolidColorQuad(
			p.solidShader,
			mgl32.Vec2{float32(p.volumeBarX), float32(p.volumeBarY)},
			mgl32.Vec2{fillW, float32(p.volumeBarH)},
			colors.White,
		); err != nil {
			return fmt.Errorf("rendering volume fill: %w", err)
		}
	}

	thickness := float32(2)
	bx := float32(p.volumeBarX)
	by := float32(p.volumeBarY)
	bw := float32(p.volumeBarW)
	bh := float32(p.volumeBarH)

	outlineRects := [4][2]mgl32.Vec2{
		{{bx, by}, {bw, thickness}},
		{{bx, by + bh - thickness}, {bw, thickness}},
		{{bx, by}, {thickness, bh}},
		{{bx + bw - thickness, by}, {thickness, bh}}, // fix: was missing `by` as Y component
	}
	for _, r := range outlineRects {
		if err := p.RenderSolidColorQuad(p.solidShader, r[0], r[1], colors.Green); err != nil {
			return fmt.Errorf("rendering volume outline: %w", err)
		}
	}
	return nil
}

// renderCursor draws the spinning triangle cursor next to the focused row.
func (p *AudioOptions) renderCursor() error {
	scaleY := float32(math.Cos(2 * math.Pi * float64(p.spinElapsed)))

	model := mgl32.Ident4()
	model = model.Mul4(mgl32.Translate3D(p.triX+triangleSize/2, p.triCenterY, 0))
	model = model.Mul4(mgl32.Scale3D(triangleSize, triangleSize*scaleY, 1))
	mvp := p.Projection.Mul4(model)

	gl.UseProgram(p.solidShader.ProgramID)
	gl.UniformMatrix4fv(p.solidShader.LocMVPMatrix, 1, false, &mvp[0])
	gl.Uniform4f(
		p.solidShader.LocColor,
		float32(colors.White.R)/255.0,
		float32(colors.White.G)/255.0,
		float32(colors.White.B)/255.0,
		float32(colors.White.A)/255.0,
	)

	gl.BindVertexArray(p.triVAO)
	gl.DrawArrays(gl.TRIANGLES, 0, 3)
	gl.BindVertexArray(0)
	gl.UseProgram(0)

	return nil
}

// ── Render ────────────────────────────────────────────────────────────────────

func (p *AudioOptions) Render() error {
	if err := p.RenderTexture(p.textShader, p.title.ID, p.title.Position(), p.title.RawDimensions(), p.title.Color); err != nil {
		return fmt.Errorf("render title: %w", err)
	}
	if err := p.RenderTexture(p.textShader, p.prompt.ID, p.prompt.Position(), p.prompt.RawDimensions(), p.prompt.Color); err != nil {
		return fmt.Errorf("render prompt: %w", err)
	}

	// Volume row
	if err := p.RenderTexture(p.textShader, p.VolumeLabel.ID, p.VolumeLabel.Position(), p.VolumeLabel.RawDimensions(), p.VolumeLabel.Color); err != nil {
		return fmt.Errorf("render volume label: %w", err)
	}
	if err := p.renderVolumeBar(); err != nil {
		return fmt.Errorf("render volume bar: %w", err)
	}
	if err := p.RenderTexture(p.textShader, p.volumePercent.ID, p.volumePercent.Position(), p.volumePercent.RawDimensions(), p.volumePercent.Color); err != nil {
		return fmt.Errorf("render volume percent: %w", err)
	}

	// Toggle
	if err := p.RenderTexture(p.textShader, p.AudioStatusToggle.ID, p.AudioStatusToggle.Position(), p.AudioStatusToggle.RawDimensions(), p.AudioStatusToggle.Color); err != nil {
		return fmt.Errorf("render audio toggle: %w", err)
	}

	// Device list
	for i := range p.AudioDeviceTextures {
		item := &p.AudioDeviceTextures[i]
		color := colors.White
		if i == p.activeDeviceIndex {
			color = colors.Green
		}
		if err := p.RenderTexture(p.textShader, item.ID, item.Position(), item.RawDimensions(), color); err != nil {
			return fmt.Errorf("render audio device %d: %w", i, err)
		}
	}

	// Spinning triangle cursor — always on top
	if err := p.renderCursor(); err != nil {
		return fmt.Errorf("render cursor: %w", err)
	}

	return nil
}

// ── Destroy ───────────────────────────────────────────────────────────────────

func (p *AudioOptions) Destroy() error {
	gl.DeleteTextures(1, &p.title.ID)
	gl.DeleteTextures(1, &p.prompt.ID)
	gl.DeleteTextures(1, &p.VolumeLabel.ID)
	gl.DeleteTextures(1, &p.volumePercent.ID)
	gl.DeleteTextures(1, &p.AudioStatusToggle.ID)
	for i := range p.AudioDeviceTextures {
		gl.DeleteTextures(1, &p.AudioDeviceTextures[i].ID)
	}
	gl.DeleteBuffers(1, &p.triVBO)
	gl.DeleteVertexArrays(1, &p.triVAO)
	return nil
}