package page

import (
	"fmt"
	"strconv"
	"strings"

	"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/db"
	"rhemawavetech.com/rhemawave/internal/fontManager"
	"rhemawavetech.com/rhemawave/internal/shaderManager"
)

type LogViewerPage struct {
	Base

	titleTextureID     uint32
	titleTextureWidth  int32
	titleTextureHeight int32

	lines              []string
	lineTextureIDs     []uint32
	lineTextureWidths  []int32
	lineTextureHeights []int32

	hintTextureID     uint32
	hintTextureWidth  int32
	hintTextureHeight int32

	scrollOffset    int32
	maxScrollOffset int32
	lineHeight      int32
	visibleHeight   int32
}

func (p *LogViewerPage) Init(app ApplicationInterface) error {
	if err := p.Base.Init(app); err != nil {
		return fmt.Errorf("failed base page initialization: %w", err)
	}

	logs, err := db.GetLogs(1000)
	if err != nil {
		return fmt.Errorf("failed to get logs: %w", err)
	}

	// Format and word-wrap each log entry
	for _, entry := range logs {
		formatted := fmt.Sprintf("[%s] [%s] %s", entry.Timestamp, entry.Level, entry.Message)
		wrapped := wrapText(formatted, 100)
		p.lines = append(p.lines, strings.Split(wrapped, "\n")...)
	}

	applicationFont, err := db.GetConfigValue("application_font")
	if err != nil {
		return fmt.Errorf("retrieving application_font from db: %w", err)
	}

	fm := fontManager.Get()
	textShader, ok := shaderManager.Get().Get("text")
	if !ok {
		return fmt.Errorf("unable to fetch text shader")
	}

	// Title texture
	titleID, titleW, titleH, err := fm.CreateStringTexture(applicationFont, "Application Logs", textShader)
	if err != nil {
		return fmt.Errorf("failed to create title texture: %w", err)
	}
	p.titleTextureID = titleID
	p.titleTextureWidth = titleW
	p.titleTextureHeight = titleH

	// Line textures
	p.lineTextureIDs = make([]uint32, len(p.lines))
	p.lineTextureWidths = make([]int32, len(p.lines))
	p.lineTextureHeights = make([]int32, len(p.lines))

	for i, line := range p.lines {
		if strings.TrimSpace(line) == "" {
			continue
		}
		texID, w, h, err := fm.CreateStringTexture(applicationFont, line, textShader)
		if err != nil {
			return fmt.Errorf("failed to create line texture: %w", err)
		}
		p.lineTextureIDs[i] = texID
		p.lineTextureWidths[i] = w
		p.lineTextureHeights[i] = h
	}

	// Hint texture
	hintText := "Arrow Keys / PgUp/PgDn to scroll | F1|2|3 to Exit"
	hintID, hintW, hintH, err := fm.CreateStringTexture(applicationFont, hintText, textShader)
	if err != nil {
		return fmt.Errorf("failed to create hint texture: %w", err)
	}
	p.hintTextureID = hintID
	p.hintTextureWidth = hintW
	p.hintTextureHeight = hintH

	return nil
}

func (p *LogViewerPage) HandleEvent(event *sdl.Event) error {
	switch e := (*event).(type) {
	case *sdl.KeyboardEvent:
		if e.Type == sdl.KEYDOWN {
			switch e.Keysym.Sym {
			case sdl.K_BACKSPACE:
				p.App.SchedulePop()
			case sdl.K_UP:
				p.scrollOffset -= p.lineHeight
				if p.scrollOffset < 0 {
					p.scrollOffset = 0
				}
			case sdl.K_DOWN:
				p.scrollOffset += p.lineHeight
				if p.scrollOffset > p.maxScrollOffset {
					p.scrollOffset = p.maxScrollOffset
				}
			case sdl.K_PAGEUP:
				p.scrollOffset -= p.visibleHeight
				if p.scrollOffset < 0 {
					p.scrollOffset = 0
				}
			case sdl.K_PAGEDOWN:
				p.scrollOffset += p.visibleHeight
				if p.scrollOffset > p.maxScrollOffset {
					p.scrollOffset = p.maxScrollOffset
				}
			case sdl.K_HOME:
				p.scrollOffset = 0
			case sdl.K_END:
				p.scrollOffset = p.maxScrollOffset
			}
		}
	case *sdl.MouseWheelEvent:
		p.scrollOffset -= e.Y * p.lineHeight * 3
		if p.scrollOffset < 0 {
			p.scrollOffset = 0
		}
		if p.scrollOffset > p.maxScrollOffset {
			p.scrollOffset = p.maxScrollOffset
		}
	}
	return nil
}

func (p *LogViewerPage) Update(dt float32) error {
	return nil
}

func (p *LogViewerPage) Render() error {
	baseFontSizeStr, err := db.GetConfigValue("init_font_size")
	if err != nil {
		return fmt.Errorf("retrieving init_font_size from db: %w", err)
	}
	baseFontSize, err := strconv.Atoi(baseFontSizeStr)
	if err != nil {
		return fmt.Errorf("parsing init_font_size: %w", err)
	}

	sm := shaderManager.Get()
	textShader, _ := sm.Get("text")

	white := sdl.Color{R: 255, G: 255, B: 255, A: 255}
	grey := sdl.Color{R: 180, G: 180, B: 180, A: 255}

	titleFontSize := int32(48)
	titleScale := float32(titleFontSize) / float32(baseFontSize)
	contentFontSize := int32(24)
	contentScale := float32(contentFontSize) / float32(baseFontSize)
	hintFontSize := int32(20)
	hintScale := float32(hintFontSize) / float32(baseFontSize)

	margin := int32(40)
	lineSpacing := int32(4)
	p.lineHeight = contentFontSize + lineSpacing

	contentColumnWidth := int32(float32(p.Base.ScreenWidth) * 0.55)
	contentLeftX := p.Base.ScreenCenterX - contentColumnWidth/2

	// Title
	titleH := float32(p.titleTextureHeight) * titleScale
	titleW := float32(p.titleTextureWidth) * titleScale
	titleX := p.Base.ScreenCenterX - int32(titleW/2)
	titleY := p.Base.ScreenHeight - margin - int32(titleH)
	p.Base.RenderTexture(textShader, p.titleTextureID, mgl32.Vec2{float32(titleX), float32(titleY)}, mgl32.Vec2{titleW, titleH}, white)

	// Hint at bottom
	hintH := float32(p.hintTextureHeight) * hintScale
	hintW := float32(p.hintTextureWidth) * hintScale
	hintX := p.Base.ScreenCenterX - int32(hintW/2)
	hintY := margin
	p.Base.RenderTexture(textShader, p.hintTextureID, mgl32.Vec2{float32(hintX), float32(hintY)}, mgl32.Vec2{hintW, hintH}, grey)

	// Content area bounds
	contentTop := titleY - margin
	contentBottom := hintY + int32(hintH) + margin
	p.visibleHeight = contentTop - contentBottom

	// Total content height
	totalContentHeight := int32(len(p.lines)) * p.lineHeight
	p.maxScrollOffset = totalContentHeight - p.visibleHeight
	if p.maxScrollOffset < 0 {
		p.maxScrollOffset = 0
	}

	// Render visible lines
	currentY := contentTop - p.lineHeight + p.scrollOffset

	for i, line := range p.lines {
		if strings.TrimSpace(line) == "" {
			currentY -= p.lineHeight
			continue
		}

		if p.lineTextureIDs[i] == 0 {
			currentY -= p.lineHeight
			continue
		}

		if currentY > contentTop || currentY+p.lineHeight < contentBottom {
			currentY -= p.lineHeight
			continue
		}

		lineW := float32(p.lineTextureWidths[i]) * contentScale
		lineH := float32(p.lineTextureHeights[i]) * contentScale

		p.Base.RenderTexture(textShader, p.lineTextureIDs[i], mgl32.Vec2{float32(contentLeftX), float32(currentY)}, mgl32.Vec2{lineW, lineH}, white)
		currentY -= p.lineHeight
	}

	return nil
}

func (p *LogViewerPage) Destroy() error {
	gl.DeleteTextures(1, &p.titleTextureID)
	gl.DeleteTextures(1, &p.hintTextureID)

	for _, texID := range p.lineTextureIDs {
		if texID != 0 {
			gl.DeleteTextures(1, &texID)
		}
	}

	return p.Base.Destroy()
}