package pigo

import (
	"errors"
	"io/ioutil"
	"math"
	"path/filepath"
	"sync"
)

// FlpCascade holds the binary representation of the facial landmark points cascade files
type FlpCascade struct {
	*PuplocCascade
	error
}

var flplocPool = sync.Pool{
	New: func() interface{} {
		return &Puploc{}
	},
}

// UnpackFlp unpacks the facial landmark points cascade file.
// This will return the binary representation of the cascade file.
func (plc *PuplocCascade) UnpackFlp(cf string) (*PuplocCascade, error) {
	flpc, err := ioutil.ReadFile(cf)
	if err != nil {
		return nil, err
	}
	return plc.UnpackCascade(flpc)
}

// GetLandmarkPoint retrieves the facial landmark point based on the pupil localization results.
func (plc *PuplocCascade) GetLandmarkPoint(leftEye, rightEye *Puploc, img ImageParams, perturb int, flipV bool) *Puploc {
	dx := (leftEye.Row - rightEye.Row) * (leftEye.Row - rightEye.Row)
	dy := (leftEye.Col - rightEye.Col) * (leftEye.Col - rightEye.Col)
	dist := math.Sqrt(float64(dx + dy))

	row := float64(leftEye.Row+rightEye.Row)/2.0 + 0.25*dist
	col := float64(leftEye.Col+rightEye.Col)/2.0 + 0.15*dist
	scale := 3.0 * dist

	flploc := flplocPool.Get().(*Puploc)
	defer flplocPool.Put(flploc)

	flploc.Row = int(row)
	flploc.Col = int(col)
	flploc.Scale = float32(scale)
	flploc.Perturbs = perturb

	if flipV {
		return plc.RunDetector(*flploc, img, 0.0, true)
	}
	return plc.RunDetector(*flploc, img, 0.0, false)
}

// ReadCascadeDir reads the facial landmark points cascade files from the provided directory.
func (plc *PuplocCascade) ReadCascadeDir(path string) (map[string][]*FlpCascade, error) {
	cascades, err := ioutil.ReadDir(path)
	if err != nil {
		return nil, err
	}

	if len(cascades) == 0 {
		return nil, errors.New("the provided directory is empty")
	}

	flpcs := make(map[string][]*FlpCascade, len(cascades))

	for _, cascade := range cascades {
		cf, err := filepath.Abs(path + "/" + cascade.Name())
		if err != nil {
			return nil, err
		}
		flpc, err := plc.UnpackFlp(cf)
		flpcs[cascade.Name()] = append(flpcs[cascade.Name()], &FlpCascade{flpc, err})
	}
	return flpcs, err
}