package editor

import (
	"moose/internal/layout"
	"moose/internal/buffer"
	"moose/internal/util"
	"fmt"
	"strings"
	"strconv"
	"github.com/gdamore/tcell/v3/color"
)

func (m *Model) Draw() {
	screen := layout.RectFromScren(m.Screen)
	main := layout.Rect{
		X: screen.X,
		Y: screen.Y,
		Width: screen.Width,
		Height: screen.Height - 2,
	}
	palette := layout.Rect{
		X: screen.X,
		Y: main.Height,
		Width: screen.Width,
		Height: 2,
	}

	copy := m.LM.Workspaces[m.LM.ActiveIdx]
	m.DrawWorkspace(&copy, main)
	m.DrawPalette(palette)	
}

func (m *Model) DrawPalette(rect layout.Rect) {
	for col := 0; col < rect.Width; col++ {
		m.Screen.SetContent(rect.X + col, rect.Y, ' ', nil, m.Style.Background(color.Black))
	}

	modeStr := m.Mode.String()
	if m.Mode == ModePalette {
		if strings.HasPrefix(m.BM.PaletteBuffer.String(), "/") {
			modeStr += " (command)"
		} else if strings.HasPrefix(m.BM.PaletteBuffer.String(), "?") {
			modeStr += " (find)"
		} else if strings.HasPrefix(m.BM.PaletteBuffer.String(), "=") {
			modeStr += " (replace)"
		}
	}

	m.Screen.PutStrStyled(rect.Width - (len(modeStr) + 1), rect.Y, strings.ToUpper(modeStr), m.Style.Background(color.Black))
	
	logStr := m.DebugLog + ", " + strings.Join(m.AM.CM.Recorded, "+") + ", " + strconv.FormatBool(m.AM.CM.Recording)
	m.Screen.PutStrStyled(1, rect.Y, logStr, m.Style.Background(color.Black))

	if m.Mode == ModePalette {
		m.Screen.PutStrStyled(0, rect.Y + 1, m.BM.PaletteBuffer.String(), m.Style)

		for _, cur := range m.BM.PaletteBuffer.CM.Cursors {
			line, col := buffer.LineCol(&m.BM.PaletteBuffer, cur.Offset)
			if line + rect.Y != rect.Y { continue }
			if col + 1 > rect.Width { continue }

			ch := buffer.RuneAt(&m.BM.PaletteBuffer, cur.Offset)

			m.Screen.SetContent(col, rect.Y + 1, ch, nil, m.Style.Reverse(true))
		}
	} else if strings.HasPrefix(m.BM.PaletteBuffer.String(), "moose.info:") {
		m.Screen.PutStrStyled(0, rect.Y + 1, string([]rune(m.BM.PaletteBuffer.String())[11:]), m.Style.Foreground(color.LightGray))
	} else if strings.HasPrefix(m.BM.PaletteBuffer.String(), "moose.warn:") {
		m.Screen.PutStrStyled(0, rect.Y + 1, string([]rune(m.BM.PaletteBuffer.String())[11:]), m.Style.Foreground(color.Orange))
	} else if strings.HasPrefix(m.BM.PaletteBuffer.String(), "moose.error:") {
		m.Screen.PutStrStyled(0, rect.Y + 1, string([]rune(m.BM.PaletteBuffer.String())[12:]), m.Style.Foreground(color.Red))
	}
}

func (m *Model) DrawWorkspace(w *layout.Workspace, rect layout.Rect) {
	m.DrawContainer(&w.RootContainer, rect)
}

func (m *Model) DrawContainer(c *layout.Container, rect layout.Rect) {
	length := util.NonNilLen(c.Children[:])
	if length == 0 {
		return
	}
	
	rect = layout.Rect{
		X: rect.X,
		Y: rect.Y,
		Width: rect.Width,
		Height: rect.Height,
	}
	rect = layout.RectDivide(rect, c.Split, length)

	for i, child := range c.Children {
		main := layout.RectDisplace(rect, c.Split, i)
		switch child.(type) {
		case layout.ContainerBuffers: {
			cb := child.(layout.ContainerBuffers)
			tabs := layout.Rect{
				X: main.X,
				Y: main.Y - 1,
				Width: main.Width,
				Height: 1,
			}
			
			m.DrawContainerTabs(&cb, tabs)
			m.DrawContainerBuffers(&cb, main)
		}
		case layout.Container: {
			c := child.(layout.Container)
			m.DrawContainer(&c, main)
		}
		}
	}
}

func (m *Model) DrawContainerTabs(c *layout.ContainerBuffers, rect layout.Rect) {
	tabs := []string{}
	for _, bufIdx := range c.Buffers {
		buf := m.BM.Buffers[bufIdx]
		if buf.Path == "" {
			tabs = append(tabs, "Buffer " + strconv.Itoa(bufIdx))
		} else {
			tabs = append(tabs, buf.Path)
		}		
	}

	length := 0
	for _, tab := range tabs {
		if length + len(tab) + 2 > rect.Width {
			m.Screen.PutStrStyled(rect.X + length, rect.Y, ">", m.Style.Foreground(color.White))
			return
		}

		m.Screen.PutStrStyled(rect.X + length, rect.Y, tab, m.Style.Background(color.Black).Foreground(color.White))
		length += len(tab) + 1
	}
}

func (m *Model) DrawContainerBuffers(c *layout.ContainerBuffers, rect layout.Rect) {
	m.DrawBuffer(&m.BM.Buffers[c.Buffers[c.ActiveIdx]], c.Buffers[c.ActiveIdx] == m.BM.CurrentIdx, rect)
}

func (m *Model) DrawBuffer(buf *buffer.Buffer, isActive bool, rect layout.Rect) {
	primary := buf.CM.Cursors[buf.CM.PrimaryIdx]
	curLine, _ := buffer.LineCol(buf, primary.Offset)
	buf.ScrollToShow(curLine, rect.Height)

	startOffset := buffer.OffsetForLine(buf, buf.TopLine)
	endOffset := buf.Rope.Len()
	if endLine := buf.TopLine + rect.Height; endLine < buffer.LineCount(buf) {
		endOffset = buffer.OffsetForLine(buf, endLine)
	}

	visible := string(buf.Rope.Slice(startOffset, endOffset))
	table := strings.SplitAfter(visible, "\n")
	for j, line := range table {
		if j + 1 > rect.Height { break }

		nums := fmt.Sprintf("%4d ", j + buf.TopLine)
		r := []rune(nums + expandTabs(line))
		if len(r) + 1 > rect.Width {
			r = r[:rect.Width]
		}

		m.Screen.PutStrStyled(rect.X, rect.Y + j, string(r), m.Style)
	}

	if isActive {
		for _, cur := range buf.CM.Cursors {
			line, col := buffer.LineCol(buf, cur.Offset)
			screenLine := line - buf.TopLine
			if screenLine < 0 || screenLine + 1 > rect.Height { continue }

			visCol := visualCol(buffer.LineText(buf, line), col)
			if visCol + 1 > rect.Width { continue }

			ch := buffer.RuneAt(buf, cur.Offset)

			if m.Mode == ModeWrite {
				m.Screen.SetContent(rect.X + visCol + 5, rect.Y + screenLine, ch, nil, m.Style.Reverse(true))
			} else {
				m.Screen.SetContent(rect.X + visCol + 5, rect.Y + screenLine, ch, nil, m.Style.Reverse(true).Foreground(color.Gray))	
			}
		}
	}
}

const tabWidth = 4

func expandTabs(s string) string {
	var b strings.Builder
	col := 0
	for _, r := range s {
		if r == '\t' {
			spaces := tabWidth - (col % tabWidth)
			b.WriteString(strings.Repeat(" ", spaces))
			col += spaces
		} else {
			b.WriteRune(r)
			col++
		}
	}
	return b.String()
}

func visualCol(lineText string, runeCol int) int {
	col := 0
	n := 0
	for _, r := range lineText {
		if n >= runeCol {
			break
		}
		if r == '\t' {
			col += tabWidth - (col % tabWidth)
		} else {
			col++
		}
		n++
	}
	return col
}