## termimg demo — full visual showcase of every rendering path.
##
## Usage:
##   nim c -r --path:src examples/demo.nim
##
## Shows: scanner pattern, rainbow gradient, target circles,
## gallery layout (3 across), column layout (3 densities stacked),
## fit-mode comparison grid, and individual renders for each protocol.

import std/[strutils, math]
import termimg

# ── Pattern generators ──────────────────────────────────────────
proc checkerboard(w, h, csize: int): seq[uint8] =
  result = newSeq[uint8](w * h * 4)
  for y in 0 ..< h:
    for x in 0 ..< w:
      let off = (y * w + x) * 4
      let bright = if ((x div csize) + (y div csize)) mod 2 == 0: 220 else: 40
      result[off + 0] = uint8(bright)
      result[off + 1] = uint8(bright)
      result[off + 2] = uint8(bright)
      result[off + 3] = 255

proc rainbowBars(w, h: int): seq[uint8] =
  result = newSeq[uint8](w * h * 4)
  for y in 0 ..< h:
    for x in 0 ..< w:
      let off = (y * w + x) * 4
      let band = float(x) / float(w) * 6.0
      let iband = int(band)
      let frac = band - float(iband)
      var r, g, b: float
      case iband
      of 0: (r, g, b) = (1.0, frac, 0.0)
      of 1: (r, g, b) = (1.0 - frac, 1.0, 0.0)
      of 2: (r, g, b) = (0.0, 1.0, frac)
      of 3: (r, g, b) = (0.0, 1.0 - frac, 1.0)
      of 4: (r, g, b) = (frac, 0.0, 1.0)
      else: (r, g, b) = (1.0, 0.0, 1.0 - frac)
      let ymul = 0.6 + 0.4 * float(y) / float(h)
      result[off + 0] = uint8(clamp(int(r * 255.0 * ymul), 0, 255))
      result[off + 1] = uint8(clamp(int(g * 255.0 * ymul), 0, 255))
      result[off + 2] = uint8(clamp(int(b * 255.0 * ymul), 0, 255))
      result[off + 3] = 255

proc targetCircle(w, h: int): seq[uint8] =
  result = newSeq[uint8](w * h * 4)
  let cx = float(w) / 2.0
  let cy = float(h) / 2.0
  let maxR = min(cx, cy)
  for y in 0 ..< h:
    for x in 0 ..< w:
      let off = (y * w + x) * 4
      let dx = float(x) - cx
      let dy = float(y) - cy
      let r = sqrt(dx * dx + dy * dy)
      let ring = int(r / (maxR / 5.0)) mod 2
      if ring == 0:
        result[off + 0] = 200; result[off + 1] = 50; result[off + 2] = 50
      else:
        result[off + 0] = 255; result[off + 1] = 255; result[off + 2] = 255
      result[off + 3] = 255

proc warmGlow(w, h: int): seq[uint8] =
  result = newSeq[uint8](w * h * 4)
  let cx = float(w) / 2.0
  let cy = float(h) / 2.0
  # maxR intentionally omitted: warmGlow normalizes by cx,cy directly
  for y in 0 ..< h:
    for x in 0 ..< w:
      let off = (y * w + x) * 4
      let dx = (float(x) - cx) / cx
      let dy = (float(y) - cy) / cy
      let dist = sqrt(dx * dx + dy * dy)
      let glow = clamp(int(255.0 * exp(-dist * 2.5)), 0, 255)
      result[off + 0] = uint8(glow)
      result[off + 1] = uint8(glow * 3 div 5)
      result[off + 2] = uint8(glow div 3)
      result[off + 3] = 255

# ── Side-by-side render helper ─────────────────────────────────
proc renderSideBySide(images: openArray[seq[uint8]],
                      widths: openArray[int],
                      heights: openArray[int],
                      caps: TerminalCapabilities,
                      opts: RenderOptions,
                      gap: int = 2): string =
  ## Renders N images at the same geometry and stitches them row-by-row.
  let geo = computeGeometry(widths[0], heights[0], caps, opts)
  var parts = newSeq[(seq[string], int)]()  # (lines, frames_consumed)
  for i in 0 ..< images.len:
    let outStr = renderHalfBlock(
      ImageData(width: widths[i], height: heights[i], data: images[i]),
      opts.backgroundRgb, geo.columns, geo.sampleHeight)
    parts.add (outStr.split('\n'), 0)
  let maxRows = min(min(parts[0][0].len, parts[1][0].len),
                    (if parts.len > 2: parts[2][0].len else: parts[1][0].len))
  for row in 0 ..< maxRows:
    for i in 0 ..< parts.len:
      if row < parts[i][0].len:
        result.add parts[i][0][row]
      if i < parts.len - 1:
        result.add spaces(gap)
    result.add "\n"

when isMainModule:
  echo ""
  echo "╭──────────────────────────────────────────────╮"
  echo "│         termimg — Full Demo                  │"
  echo "╰──────────────────────────────────────────────╯"
  echo ""

  let caps = detectCapabilities()

  echo "Terminal: ", caps.columns, "x", caps.rows, " cells"
  echo "Cell:     ", caps.cell.width, "x", caps.cell.height, " px"
  echo ""

  echo "Detected protocols:"
  for proto in [ptKitty, ptIterm2, ptSixel, ptQuarterBlock, ptHalfBlock]:
    let mark = if caps.supports(proto): " ✓" else: " ✗"
    echo "  ", ($proto).align(14), mark
  echo ""

  # ── Pattern generation ──────────────────────────────────────────
  const patternW = 64
  const patternH = 48
  let chk = checkerboard(patternW, patternH, 8)
  let rnb = rainbowBars(patternW, patternH)
  let tgt = targetCircle(patternW, patternH)
  let glow = warmGlow(patternW, patternH)

  # ── 1. Gallery: 3 patterns side-by-side ─────────────────────────
  echo "── Gallery: 3 patterns side-by-side ──"
  var optsGal = defaultOptions()
  optsGal.maxWidth = (caps.columns - 4) div 3
  optsGal.fit = fmWidth
  stdout.write(renderSideBySide([chk, rnb, tgt], [patternW, patternW, patternW],
                                 [patternH, patternH, patternH], caps, optsGal))
  echo ""

  # ── 2. All four patterns in a column (thumbnail pipeline) ──────
  echo "── All four patterns (thumbnail pipeline) ──"
  let thumbOpts = thumbnailOptions()
  for (name, pix) in [("Checkerboard", chk), ("Rainbow bars", rnb),
                       ("Target circles", tgt), ("Warm glow", glow)]:
    echo "  ", name, ":"
    let outStr = renderImageRgba(pix, patternW, patternH, caps, thumbOpts)
    stdout.write(outStr)
    stdout.write("\n")
  echo ""

  # ── 3. Column layout: rainbow at 3 densities for comparison ────
  echo "── Column layout: rainbow at 3 block densities ──"
  let colW = caps.columns - 2
  for density in [bdFull, bdHalf, bdQuarter]:
    var opts = defaultOptions()
    opts.density = density
    opts.maxWidth = colW
    opts.fit = fmWidth
    let geo = computeGeometry(patternW, patternH, caps, opts)
    let outStr = renderHalfBlock(
      ImageData(width: patternW, height: patternH, data: rnb),
      opts.backgroundRgb, geo.columns, geo.sampleHeight)
    stdout.write(outStr)
    stdout.write("\n")
    echo "  ($1 — $2 cols x $3 samples)" % [$density, $geo.columns, $geo.sampleHeight]
    echo ""
  echo ""

  # ── 4. Fit-mode comparison grid (quarter-block, dithered) ──────
  echo "── Fit-mode grid: target circles at 4 fit modes ──"
  let halfW = caps.columns div 2 - 1
  for fit in [fmContain, fmWidth, fmOriginal, fmStretch]:
    var opts = defaultOptions()
    opts.fit = fit
    opts.maxWidth = halfW
    opts.density = bdQuarter
    let geo = computeGeometry(patternW, patternH, caps, opts)
    let outStr = renderQuarterBlock(
      ImageData(width: patternW, height: patternH, data: tgt),
      opts.backgroundRgb, geo.columns, geo.sampleHeight, dither = true)
    stdout.write(outStr)
    stdout.write("\n")
    echo "  ($1 — $2 px, $3 cols x $4 samples)" % [
      $fit, $geo.pixelWidth & "x" & $geo.pixelHeight,
      $geo.columns, $geo.sampleHeight]
    echo ""
  echo ""

  # ── 5. Individual renders per protocol ──────────────────────────
  echo "── Default render (half-block, contain fit) ──"
  let out1 = renderImageRgba(chk, patternW, patternH, caps, defaultOptions())
  stdout.write(out1)
  stdout.write("\n")
  echo ""

  echo "── Quarter-block thumbnail (40 cols, dithered) ──"
  let out2 = renderImageRgba(rnb, patternW, patternH, caps, thumbnailOptions())
  stdout.write(out2)
  stdout.write("\n")
  echo ""

  # ── 6. Extreme aspect-ratio demo ────────────────────────────────
  echo "── Wide vs tall: checkerboard at extreme ratios ──"
  var optsW = defaultOptions()
  optsW.maxWidth = caps.columns - 2
  optsW.fit = fmWidth
  let geoW = computeGeometry(patternW, patternH, caps, optsW)
  let outW = renderHalfBlock(
    ImageData(width: patternW, height: patternH, data: chk),
    optsW.backgroundRgb, geoW.columns, geoW.sampleHeight)
  stdout.write(outW)
  echo "  (wide: $1 cols x $2 samples)" % [$geoW.columns, $geoW.sampleHeight]
  echo ""

  let tallPixels = checkerboard(patternH, patternW, 6)  # 48x64
  var optsT = defaultOptions()
  optsT.maxHeight = caps.rows - 4
  optsT.fit = fmContain
  let geoT = computeGeometry(patternH, patternW, caps, optsT)
  let outT = renderHalfBlock(
    ImageData(width: patternH, height: patternW, data: tallPixels),
    optsT.backgroundRgb, geoT.columns, geoT.sampleHeight)
  stdout.write(outT)
  echo "  (tall: $1 cols x $2 samples)" % [$geoT.columns, $geoT.sampleHeight]
  echo ""

  echo "╭──────────────────────────────────────────────╮"
  echo "│        Demo complete. All renders done.      │"
  echo "╰──────────────────────────────────────────────╯"