//! QuickDraw PICT format loader.

use crate::durandal::{bin::*, err::*, image::*};
use generic_array::*;

/// Reads a `PixMap` header.
fn read_pm_header<'a>(b: &'a [u8],
                      pack: bool,
                      clip: bool,
                      im: &Image8)
                      -> ResultS<(&'a [u8], Header)>
{
   read_data! {
      36, BE in b =>
      pt_fl  = u16[0];
      top    = u16[2] as usize;
      left   = u16[4] as usize;
      bottom = u16[6] as usize;
      right  = u16[8] as usize;
      pack_t = u16[12];
      depth  = u16[28];
   }

   let pack_t = PackType::from_repr(pack_t)?;

   if pt_fl & 0x8000 == 0 {
      bail!("PICT1 not supported");
   }

   if right - left != im.w() || bottom - top != im.h() {
      bail!("image bounds are incorrect");
   }

   let mut p = 46;

   // get CLUT if packed
   let clut = if pack {
      let (clut, sz) = get_clut(&b[p..])?;
      p += sz;
      Some(clut)
   } else {
      None
   };

   p += 18; // srcRect, dstRect, mode

   if clip {
      p += u16b(&b[p..]) as usize; // maskRgn
   }

   let rle = pack_t == PackType::Default ||
             pack_t == PackType::Rle16 && depth == 16 ||
             pack_t == PackType::Rle32 && depth == 32;

   let pitch = (pt_fl & 0x3FFF) as usize;

   Ok((&b[p..], Header{pitch, pack_t, depth, clut, rle}))
}

/// Reads an indexed `PixMap`.
fn read_pm_ind(mut im: Image8, b: &[u8], hdr: Header) -> ResultS<Image8>
{
   let clut = ok!(hdr.clut, "no CLUT in indexed mode")?;
   let mut p = 0;

   if hdr.pitch < 8 && hdr.depth == 8 {
      // uncompressed 8-bit colormap indices
      for _ in 0..im.h() {
         for _ in 0..im.w() {
            let idx = b[p] as usize;
            im.cr.push(ok!(clut.get(idx), "invalid index")?.clone());
            p += 1;
         }
      }

      Ok(im)
   } else if hdr.rle {
      // RLE compressed 1, 2, 4 or 8 bit colormap indices
      for _ in 0..im.h() {
         let (d, pp) = read_rle(&b[p..], hdr.pitch, false)?;
         let d = if hdr.depth < 8 {
            expand_data(d, hdr.depth)?
         } else {
            d
         };

         p += pp;

         for &idx in &d {
            im.cr
              .push(ok!(clut.get(idx as usize), "invalid index")?.clone());
         }
      }

      Ok(im)
   } else {
      bail!("invalid configuration")
   }
}

/// Reads a R5G5B5 `PixMap`.
fn read_pm_16(mut im: Image8, b: &[u8], hdr: Header) -> ResultS<Image8>
{
   let mut p = 0;

   if hdr.pitch < 8 || hdr.pack_t == PackType::None {
      // uncompressed R5G5B5
      for _ in 0..im.h() {
         for _ in 0..im.w() {
            let cr = u16b(&b[p..]);
            im.cr.push(r5g5b5_to_rgb8(cr));
            p += 2;
         }
      }

      Ok(im)
   } else if hdr.rle {
      // RLE compressed R5G5B5
      for _ in 0..im.h() {
         let (d, pp) = read_rle(&b[p..], hdr.pitch, true)?;

         p += pp;

         for x in 0..im.w() {
            let cr = u16b(&d[x * 2..]);
            im.cr.push(r5g5b5_to_rgb8(cr));
         }
      }

      Ok(im)
   } else {
      bail!("invalid configuration")
   }
}

/// Reads a RGB8 `PixMap`.
fn read_pm_32(mut im: Image8, b: &[u8], hdr: Header) -> ResultS<Image8>
{
   let mut p = 0;

   if hdr.pitch < 8 ||
      hdr.pack_t == PackType::None ||
      hdr.pack_t == PackType::NoPad
   {
      // uncompressed RGB8 or XRGB8
      for _ in 0..im.h() {
         for _ in 0..im.w() {
            if hdr.pack_t != PackType::NoPad {
               p += 1;
            }

            read_data! {
               p + 3, BE in b =>
               r = u8[p];
               g = u8[p + 1];
               b = u8[p + 2];
            }

            im.cr.push(Color8::new(r, g, b));

            p += 3;
         }
      }

      Ok(im)
   } else if hdr.rle {
      // RLE compressed RGB8
      let pitch = hdr.pitch - im.w(); // remove padding byte from pitch
      for _ in 0..im.h() {
         let (d, pp) = read_rle(&b[p..], pitch, false)?;

         p += pp;

         for x in 0..im.w() {
            let r = d[x + im.w()];
            let g = d[x + im.w() * 2];
            let b = d[x + im.w() * 3];
            im.cr.push(Color8::new(r, g, b));
         }
      }

      Ok(im)
   } else {
      bail!("invalid configuration")
   }
}

/// Process a `CopyBits` operation.
fn read_pm_area(im: Image8, b: &[u8], pack: bool, clip: bool)
                -> ResultS<Image8>
{
   let p = if pack {0} else {4};
   let (b, hdr) = read_pm_header(&b[p..], pack, clip, &im)?;

   match hdr.depth {
      1 | 2 | 4 | 8 => read_pm_ind(im, b, hdr),
      16 => read_pm_16(im, b, hdr),
      32 => read_pm_32(im, b, hdr),
      _ => bail!("invalid bit depth"),
   }
}

/// Load a `PICT` image.
pub fn load_pict(b: &[u8]) -> ResultS<Image8>
{
   read_data! {
      10, BE in b =>
      h = u16[6] as usize;
      w = u16[8] as usize;
   }

   let im = Image8::new(w, h);

   let mut p = 10; // size of header

   while p < b.len() {
      read_data! {
         p + 2, BE in b =>
         op = u16[p];
      }

      p += 2;

      match op {
         0x0098 => {
            // PackBitsRect
            return read_pm_area(im, &b[p..], true, false);
         }
         0x0099 => {
            // PackBitsRgn
            return read_pm_area(im, &b[p..], true, true);
         }
         0x009a => {
            // DirectBitsRect
            return read_pm_area(im, &b[p..], false, false);
         }
         0x009b => {
            // DirectBitsRgn
            return read_pm_area(im, &b[p..], false, true);
         }
         0x8200 => {
            // CompressedQuickTime
            unimplemented!();
         }
         0x00ff => {
            // OpEndPic
            break;
         }
         // help i'm trapped in an awful metafile format from the 80s
         0x0000 |           // NoOp
         0x001c |           // HiliteMode
         0x001e |           // DefHilite
         0x0038 |           // FrameSameRect
         0x0039 |           // PaintSameRect
         0x003a |           // EraseSameRect
         0x003b |           // InvertSameRect
         0x003c |           // FillSameRect
         0x8000 |           // Reserved
         0x8100 => (),      // Reserved
         0x0003 |           // TxFont
         0x0004 |           // TxFace
         0x0005 |           // TxMode
         0x0008 |           // PnMode
         0x000d |           // TxSize
         0x0011 |           // VersionOp
         0x0015 |           // PnLocHFrac
         0x0016 |           // ChExtra
         0x0023 |           // ShortLineFrom
         0x00a0 => p += 2,  // ShortComment
         0x0006 |           // SpExtra
         0x0007 |           // PnSize
         0x000b |           // OvSize
         0x000c |           // Origin
         0x000e |           // FgCol
         0x000f |           // BkCol
         0x0021 => p += 4,  // LineFrom
         0x001a |           // RGBFgCol
         0x001b |           // RGBBkCol
         0x001d |           // TxRatio
         0x0022 => p += 6,  // ShortLine
         0x0002 |           // BkPat
         0x0009 |           // PnPat
         0x0010 |           // TxRatio
         0x0020 |           // Line
         0x002e |           // GlyphState
         0x0030 |           // FrameRect
         0x0031 |           // PaintRect
         0x0032 |           // EraseRect
         0x0033 |           // InvertRect
         0x0034 => p += 8,  // FillRect
         0x002d => p += 10, // LineJustify
         0x0001 => p += (u16b(&b[p..  ]) & !1) as usize,     // Clip
         0x00a1 => p += (u16b(&b[p+2..]) & !1) as usize + 2, // LongComment
         0x100..=
         0x7fff => p += (op >> 8) as usize * 2, // Reserved
         _      => {
            bail!("invalid op in PICT");
         }
      }
   }

   Err(err_msg("no image in data"))
}

/// Read a `ColorTable` structure.
pub fn get_clut(b: &[u8]) -> ResultS<(Vec<Color8>, usize)>
{
   read_data! {
      8, BE in b =>
      dev = u16[4];
      num = u16[6] as usize;
   }

   let dev = dev & 0x8000 != 0;
   let num = num + 1;

   let mut p = 8;
   let mut clut = vec![Color8::new(0, 0, 0); num];

   for i in 0..num {
      read_data! {
         p + 8, BE in b =>
         n = u16[p] as usize;
         r = u8[p + 2];
         g = u8[p + 4];
         b = u8[p + 6];
      }

      // with device mapping, we ignore the index entirely
      let n = if dev {i} else {n};

      *ok!(clut.get_mut(n), "invalid index")? = Color8::new(r, g, b);

      p += 8;
   }

   Ok((clut, p))
}

/// Read run-length encoded data.
pub fn read_rle(b: &[u8], pitch: usize, ln: bool) -> ResultS<(Vec<u8>, usize)>
{
   let mut p = 0;
   let mut o = Vec::with_capacity(pitch);

   let sz = if pitch > 250 {
      (u16b(b) as usize + 2, p += 2).0
   } else {
      (b[0] as usize + 1, p += 1).0
   };

   while p < sz {
      let szf = b[p];
      let cmp = szf & 0x80 != 0;
      let len = if cmp {!szf + 2} else {szf + 1} as usize;

      p += 1;
      o.reserve(len);

      if ln {
         read_rle_data(cmp, len, &mut o, || (arr![u8; b[p], b[p+1]], p += 2).0);
      } else {
         read_rle_data(cmp, len, &mut o, || (arr![u8; b[p]        ], p += 1).0);
      }
   }

   if o.len() == pitch {
      Ok((o, p))
   } else {
      Err(err_msg("incorrect size for compressed scanline"))
   }
}

/// Read a sequence of packed RLE data.
fn read_rle_data<F, N>(cmp: bool, len: usize, out: &mut Vec<u8>, mut read: F)
   where F: FnMut() -> GenericArray<u8, N>,
         N: ArrayLength<u8>
{
   if cmp {
      let d = read();
      for _ in 0..len {
         for v in d.iter() {
            out.push(*v);
         }
      }
   } else {
      for _ in 0..len {
         let d = read();
         for v in d.iter() {
            out.push(*v);
         }
      }
   }
}

/// Expand packed pixel data based on bit depth.
pub fn expand_data(b: Vec<u8>, depth: u16) -> ResultS<Vec<u8>>
{
   let mut o = Vec::with_capacity(match depth {
                                     4 => b.len() * 2,
                                     2 => b.len() * 4,
                                     1 => b.len() * 8,
                                     _ => bail!("invalid bit depth"),
                                  });

   for ch in b {
      match depth {
         4 => {for i in (0..=1).rev() {o.push(ch >> (i * 4) & 0xF_u8);}}
         2 => {for i in (0..=3).rev() {o.push(ch >> (i * 2) & 0x3_u8);}}
         1 => {for i in (0..=7).rev() {o.push(ch >>  i      & 0x1_u8);}}
         _ => bail!("invalid bit depth"),
      }
   }

   Ok(o)
}

struct Header
{
   pitch:  usize,
   pack_t: PackType,
   depth:  u16,
   clut:   Option<Vec<Color8>>,
   rle:    bool,
}

c_enum! {
   #[derive(PartialEq)]
   enum PackType: u16
   {
      0 => Default,
      1 => None,
      2 => NoPad,
      3 => Rle16,
      4 => Rle32,
   }
}

// EOF