package codex

import (
  "fmt"
  "strconv"
)

type CodexBitmap struct {
  id      string
  fields  []Codex 
}

func (c *CodexBitmap) init(cfg map[string]interface{}) {
  if v, ok := cfg["id"].(string); ok {
    c.id = v
  } else {
    panic(fmt.Sprintf("Invalid CodexBitmap.ID %+v", cfg))
  }
  if v, ok := cfg["fields"].([]interface{}); ok {
    c.fields = make([]Codex, len(v))
    for i,f := range v {
      if fm, ok := f.(map[string]interface{}); ok {
        c.fields[i] = parseType(fm)
      } else {
        panic(fmt.Sprintf("Invalid field %d %+v", i, f))
      }
    }
  } else {
    panic(fmt.Sprintf("Invalid CodexBitmap.Fields %+v", cfg))
  }
}

func (c *CodexBitmap) ID() string {
  return c.id
}

func (c *CodexBitmap) Decode(data []byte, pos int, value interface{}) (int, error) {
  ppos := pos + 16
  if len(data) < ppos {
    return pos, fmt.Errorf("incomplete packet %d %d", len(data), ppos)
  }
  var err error
  bi := 0
  var bitmap [128]bool
  for i := pos; i<ppos; i++ {
    bbi, err := strconv.ParseInt(string(data[i:i+1]), 16, 32)
    if err != nil {
      panic(err)
    }
    ba := int64(8)
    for j := 1; j <= 4; j++ {
      bitmap[bi] = (bbi & ba) != 0
      ba >>= 1
      bi++
    }
  }
  if bitmap[0] {
    ppos1 := ppos
    ppos = ppos + 16
    if len(data) < ppos {
      return pos, fmt.Errorf("incomplete packet %d %d", len(data), ppos)
    }
    for i := ppos1; i<ppos; i++ {
      bbi, err := strconv.ParseInt(string(data[i:i+1]), 16, 32)
      if err != nil {
        panic(err)
      }
      ba := int64(8)
      for j := 1; j <= 4; j++ {
        bitmap[bi] = (bbi & ba) != 0
        ba >>= 1
        bi++
      }
    }
  }
  for i := 0; i < 127; i++ {
    if bitmap[i+1] {
      ppos, err = c.fields[i].Decode(data, ppos, value)
      if err != nil {
        return pos, err
      }
    }
  }
  return ppos, nil
}

func (c *CodexBitmap) Encode(data []byte, pos int, value interface{}) (int, error) {
  if vm, ok := value.(map[string]interface{}); ok {
    ppos := pos
    var bitmap [128]bool
    for i, f := range c.fields {
      bitmap[i+1] = vm[f.ID()] != nil
    }
    for i := 64; i<128; i++ {
      if bitmap[i] {
        bitmap[0] = true
        break
      }
    }
    bi := 0
    for i := 0; i<16; i++ {
      b := byte(0)
      ba := byte(8)
      for j := 1; j <= 4; j++ {
        if bitmap[bi] {
          b |= ba
        }
        ba >>= 1
        bi += 1
      }
      if b > 9 {
        data[ppos] = 38 + b
      } else {
        data[ppos] = 48 + b
      }
      ppos +=1
    }
    if bitmap[0] {
      for i := 0; i<16; i++ {
        b := byte(0)
        ba := byte(8)
        for j := 1; j <= 4; j++ {
          if bitmap[bi] {
            b |= ba
          }
          ba >>= 1
          bi += 1
        }
        if b > 9 {
          data[ppos] = 38 + b
        } else {
          data[ppos] = 48 + b
        }
        ppos +=1
      }
    }
    var err error
    for i, f := range c.fields {
      if bitmap[i+1] {
        ppos, err = f.Encode(data, ppos, value)
        if err != nil {
          return pos, err
        }
      }
    }
    return ppos, nil
  }
  panic(fmt.Sprintf("Invalid value type [%s] %+v", c.id, value))
}