package game

import (
	"fmt"
	"math"
	"strconv"
	"strings"

	"thehouseoficarus/internal/casino"
	"thehouseoficarus/internal/color"
	"thehouseoficarus/internal/ui"
)

// The rectangle is drawn on a fixed pitch: eight lanes at x = 3+6k, pegs on
// the boundaries at x = 6+6k, and walls at both ends. Every scanline has the
// same width, so a drop prints one row per tick and the ball's path reads as a
// diagonal column of frames. The right wall sits one half-lane past the last
// lane, mirroring the left wall, so the outer slots have the same clearance on
// both sides.
const (
	pachinkoLanes  = 8
	pachinkoRows   = 20
	pachinkoPitch  = 6
	pachinkoWidth  = pachinkoLanes*pachinkoPitch + 1
	pachinkoBallX  = 3
	pachinkoPegGap = 6
)

// pachinkoLaneX is the fixed column of a lane on an even scanline; the prize
// row and the top labels use it so a settled ball lines up with its pocket.
func pachinkoLaneX(lane int) int { return pachinkoBallX + pachinkoPitch*lane }

// pachinkoDropX staggers the ball's column on odd rows so a ball that holds its
// lane visibly weaves between the pins instead of sliding down a static grid.
func pachinkoDropX(row, lane int) int {
	if row%2 == 0 {
		return pachinkoLaneX(lane)
	}
	return pachinkoPitch * (lane + 1)
}

// pachinkoGradientRGB gives the board a warm jewel ramp: deep violet walls,
// through blue and teal, to a golden-red right edge.
func pachinkoGradientRGB(x int) [3]int {
	stops := [5][3]int{{150, 80, 255}, {60, 170, 255}, {40, 230, 190}, {255, 210, 60}, {255, 90, 70}}
	distance := float64(x) / float64(pachinkoWidth-1)
	segment := min(3, int(distance*4))
	blend := distance*4 - float64(segment)
	var rgb [3]int
	for i := range rgb {
		rgb[i] = int(math.Round(float64(stops[segment][i])*(1-blend) + float64(stops[segment+1][i])*blend))
	}
	return rgb
}

func pachinkoColorAt(x int, scale float64) int {
	rgb := pachinkoGradientRGB(x)
	return color.NearestXterm256(
		max(0, min(255, int(float64(rgb[0])*scale))),
		max(0, min(255, int(float64(rgb[1])*scale))),
		max(0, min(255, int(float64(rgb[2])*scale))))
}

func pachinkoPegColor(x int) int    { return pachinkoColorAt(x, 0.45) }
func pachinkoWallColor(x int) int   { return pachinkoColorAt(x, 0.85) }
func pachinkoHeaderColor(x int) int { return pachinkoColorAt(x, 1.0) }

// pachinkoPocketColor maps a prize to a readable color; doubling shifts an
// already-valuable pocket hotter.
func pachinkoPocketColor(p casino.PachinkoPocket, doubling int) int {
	switch {
	case p.Double:
		if doubling > 0 {
			return 201 // bright magenta
		}
		return 198 // magenta
	case p.Value >= 100:
		return 51 // neon cyan
	case p.Value >= 10:
		if doubling > 0 {
			return 226
		}
		return 220 // gold
	case p.Value >= 5:
		return 208 // orange
	case p.Value >= 2:
		return 46 // green
	case p.Value >= 1:
		return 49 // teal: break-even and small fractions
	case p.Value > 0:
		return 245 // dim fraction
	default:
		return 240 // dim slate for 0x
	}
}

func pachinkoPocketBold(p casino.PachinkoPocket, doubling int) bool {
	return !p.Double && (p.Value >= 2 || doubling > 0)
}

type pachinkoCell struct {
	glyph rune
	fg    int
	bold  bool
}

type pachinkoLine [pachinkoWidth]pachinkoCell

func newPachinkoLine() pachinkoLine {
	var line pachinkoLine
	for x := range line {
		line[x] = pachinkoCell{glyph: ' ', fg: -1}
	}
	return line
}

func (line *pachinkoLine) put(x int, glyph rune, fg int) {
	if x >= 0 && x < len(line) {
		line[x] = pachinkoCell{glyph: glyph, fg: fg}
	}
}

func (line *pachinkoLine) putBold(x int, glyph rune, fg int) {
	if x >= 0 && x < len(line) {
		line[x] = pachinkoCell{glyph: glyph, fg: fg, bold: true}
	}
}

// centeredStart returns the first cell of a text of length n centered in the
// 6-wide lane k cell.
func pachinkoCenteredStart(lane, n int) int {
	if n > pachinkoPitch {
		n = pachinkoPitch
	}
	return pachinkoPitch*lane + (pachinkoPitch-n+1)/2
}

func (line pachinkoLine) render(mode string) string {
	var b strings.Builder
	for x := 0; x < len(line); {
		cell := line[x]
		end := x + 1
		for end < len(line) && line[end].fg == cell.fg && line[end].bold == cell.bold {
			end++
		}
		var text strings.Builder
		for _, c := range line[x:end] {
			text.WriteRune(c.glyph)
		}
		b.WriteString(color.Render(mode, color.ColorSpec{Fg: cell.fg, Bg: -1, Bold: cell.bold}, text.String()))
		x = end
	}
	return b.String()
}

func pachinkoGlyphs(unicode bool) (ball, peg rune) {
	if unicode {
		return '●', '·'
	}
	return 'o', '.'
}

// pachinkoScanline draws one staggered peg row, optionally with the ball in a
// lane.
func pachinkoScanline(row, ballLane int, mode string, unicode bool) string {
	ball, peg := pachinkoGlyphs(unicode)
	line := newPachinkoLine()
	line.put(0, '|', pachinkoWallColor(0))
	line.put(pachinkoWidth-1, '|', pachinkoWallColor(pachinkoWidth-1))
	if row%2 == 0 {
		for k := 0; k < pachinkoLanes-1; k++ {
			x := pachinkoPegGap + pachinkoPitch*k
			line.put(x, peg, pachinkoPegColor(x))
		}
	} else {
		for k := 0; k < pachinkoLanes; k++ {
			x := pachinkoBallX + pachinkoPitch*k
			line.put(x, peg, pachinkoPegColor(x))
		}
	}
	if ballLane >= 0 && ballLane < pachinkoLanes {
		line.putBold(pachinkoDropX(row, ballLane), ball, 231)
	}
	return line.render(mode)
}

// pachinkoPocketLabel is the text shown for a landed value after doublings.
func pachinkoPocketLabel(p casino.PachinkoPocket, doubling int) string {
	if p.Double {
		return "DBL"
	}
	value := p.Value
	for i := 0; i < doubling && i < 62; i++ {
		value *= 2
		if value > casino.MaxCredits {
			return "MAX"
		}
	}
	if value > casino.MaxCredits {
		return "MAX"
	}
	return strconv.FormatFloat(value, 'f', -1, 64) + "x"
}

// pachinkoPocketRow prints the prize row, marking the landed pocket.
func pachinkoPocketRow(s *casino.PachinkoSnapshot, mode string) string {
	var b strings.Builder
	for lane := 0; lane < pachinkoLanes; lane++ {
		pocket := s.Pockets[lane]
		label := pachinkoPocketLabel(pocket, s.Doubling)
		landed := s.Landing == lane && (s.Phase == "result" || s.Phase == "dropping")
		text := label
		if landed && len([]rune("["+label+"]")) <= pachinkoPitch {
			text = "[" + label + "]"
		}
		fg := pachinkoPocketColor(pocket, s.Doubling)
		bold := pachinkoPocketBold(pocket, s.Doubling)
		if landed {
			bold = true
			switch {
			case pocket.Double:
				fg = 201
			case pocket.Value >= 100:
				fg = 51
			default:
				fg = 226
			}
		}
		runes := []rune(text)
		if len(runes) > pachinkoPitch {
			runes = runes[:pachinkoPitch]
		}
		lead := pachinkoCenteredStart(lane, len(runes)) - pachinkoPitch*lane
		if lead < 0 {
			lead = 0
		}
		trail := pachinkoPitch - lead - len(runes)
		if trail < 0 {
			trail = 0
		}
		b.WriteString(strings.Repeat(" ", lead))
		b.WriteString(color.Render(mode, color.ColorSpec{Fg: fg, Bg: -1, Bold: bold}, string(runes)))
		b.WriteString(strings.Repeat(" ", trail))
	}
	// The cells span pachinkoLanes*pachinkoPitch; pad to the board width.
	b.WriteString(strings.Repeat(" ", pachinkoWidth-pachinkoLanes*pachinkoPitch))
	return b.String()
}

// renderPachinkoBoard draws the whole rectangle: the numbered top slots, the
// peg rows, and the prize row. The labels sit in the gaps of the first peg row
// (not on its pins) so they read as slots to drop the ball into. The first
// drawn row is the even entry row, whose pins bracket each slot number.
func renderPachinkoBoard(s *casino.PachinkoSnapshot, mode string, unicode bool) string {
	lines := make([]string, 0, pachinkoRows+3)
	header := newPachinkoLine()
	for lane := 0; lane < pachinkoLanes; lane++ {
		x := pachinkoLaneX(lane)
		header.put(x, rune('1'+lane), pachinkoHeaderColor(x))
	}
	lines = append(lines, header.render(mode))
	for row := 0; row <= pachinkoRows; row++ {
		lines = append(lines, pachinkoScanline(row, -1, mode, unicode))
	}
	lines = append(lines, pachinkoPocketRow(s, mode))
	return strings.Join(lines, "\n")
}

// pachinkoBlankPocketRow prints a prize row of question marks for the
// reference view, where no board has been dealt yet.
func pachinkoBlankPocketRow(mode string) string {
	var b strings.Builder
	for lane := 0; lane < pachinkoLanes; lane++ {
		x := pachinkoLaneX(lane)
		fg := pachinkoColorAt(x, 0.6)
		lead := pachinkoCenteredStart(lane, 1) - pachinkoPitch*lane
		if lead < 0 {
			lead = 0
		}
		trail := pachinkoPitch - lead - 1
		if trail < 0 {
			trail = 0
		}
		b.WriteString(strings.Repeat(" ", lead))
		b.WriteString(color.Render(mode, color.ColorSpec{Fg: fg, Bg: -1, Bold: true}, "?"))
		b.WriteString(strings.Repeat(" ", trail))
	}
	b.WriteString(strings.Repeat(" ", pachinkoWidth-pachinkoLanes*pachinkoPitch))
	return b.String()
}

// renderPachinkoBlankBoard draws the numbered top slots, the peg rows, and a
// row of question marks in place of the pockets.
func renderPachinkoBlankBoard(mode string, unicode bool) string {
	lines := make([]string, 0, pachinkoRows+3)
	header := newPachinkoLine()
	for lane := 0; lane < pachinkoLanes; lane++ {
		x := pachinkoLaneX(lane)
		header.put(x, rune('1'+lane), pachinkoHeaderColor(x))
	}
	lines = append(lines, header.render(mode))
	for row := 0; row <= pachinkoRows; row++ {
		lines = append(lines, pachinkoScanline(row, -1, mode, unicode))
	}
	lines = append(lines, pachinkoBlankPocketRow(mode))
	return strings.Join(lines, "\n")
}

// pachinkoOddsColor maps a prize tier to the color its label uses in the table.
func pachinkoOddsColor(label string) int {
	switch label {
	case "1.7x":
		return 49
	case "2x":
		return 46
	case "5x":
		return 208
	case "10x":
		return 220
	case "DOUBLE":
		return 198
	case "100x":
		return 51
	default:
		return 240
	}
}

// renderPachinkoOddsTable lays the board composition out as a bordered table.
// The chance column carries the exact percentages, so it is blanked unless the
// player carries a House Edge instrument.
func renderPachinkoOddsTable(odds []casino.PachinkoPrizeOdds, mode string, unicode, showOdds bool, precision int) string {
	rows := make([][]string, 0, len(odds))
	for _, odd := range odds {
		chance := "?"
		if showOdds {
			if odd.Chance > 0 {
				chance = strconv.FormatFloat(100*odd.Chance, 'f', precision, 64) + "%"
			} else {
				chance = "—"
			}
		}
		label := color.Render(mode, color.ColorSpec{Fg: pachinkoOddsColor(odd.Label), Bg: -1, Bold: odd.Label == "DOUBLE" || odd.Label == "100x"}, odd.Label)
		rows = append(rows, []string{label, chance, odd.Odds})
	}
	table := ui.Table{
		Title:   "Pachinko pay table",
		Columns: []string{"Prize", "Chance", "Odds"},
		Rows:    rows,
	}
	return strings.Join(table.Render(unicode, 0), "\n")
}

// pachinkoIntro is the framing text every player sees, whether they are just
// sitting down or reading the table reference. It is never gated by items.
func pachinkoIntro(mode string) string {
	return color.Render(mode, color.ColorSpec{Fg: 253, Bg: -1}, "You stand atop a giant peg board with 8 slots and 20 rows. Win multipliers are randomized as soon as you place a bet.")
}

// renderPachinkoReference is the table command's view: the framing text, a
// blank board, and the pay table. The RTP footer appears only with a House Edge
// instrument, matching the gated chance column.
func renderPachinkoReference(s *casino.PachinkoSnapshot, mode string, unicode, showOdds bool, precision int) string {
	parts := []string{
		pachinkoIntro(mode),
		"",
		renderPachinkoBlankBoard(mode, unicode),
		"",
		renderPachinkoOddsTable(s.Odds, mode, unicode, showOdds, precision),
	}
	if showOdds {
		format := func(v float64) string { return strconv.FormatFloat(v, 'f', precision, 64) + "%" }
		parts = append(parts, "", fmt.Sprintf("Best slot: %s RTP    Random slot: %s RTP", format(s.RTP), format(s.Uniform)))
	}
	return strings.Join(parts, "\n")
}

// renderPachinko renders the game view: two scanlines per tick while the ball
// falls, the full board while choosing, the prize row once it settles, and the
// blank board plus pay table for the table command. showOdds controls whether
// the exact percentages appear; precision is the House Edge instrument's
// rounding (0 or 2 decimal places).
func renderPachinko(s *casino.PachinkoSnapshot, mode string, unicode, showOdds bool, precision int) string {
	if s == nil {
		return ""
	}
	switch s.Phase {
	case "paytable":
		return renderPachinkoReference(s, mode, unicode, showOdds, precision)
	case "idle":
		// Sitting down shows the framing text and the menu, but not the blank
		// board or pay table; those wait for the table command.
		return pachinkoIntro(mode)
	case "dropping":
		return pachinkoScanline(s.Row, s.Lane, mode, unicode)
	case "result":
		// The ball path is already on screen; the settled view is just the
		// prize row so the multipliers land as the last line, with no repeated
		// board or number header.
		return pachinkoPocketRow(s, mode)
	default:
		return renderPachinkoBoard(s, mode, unicode)
	}
}