package edid

import (
	"fmt"
	"os"

	"github.com/anoopengineer/edidparser/edid"
)

// EDID represents a display's extended display identification data:
// https://wikipedia.org/wiki/Extended_Display_Identification_Data.
type EDID struct {
	*edid.Edid
	bytes []byte
}

// "ManufacturerID-ProductCode" from EDID data.
func (edid *EDID) String() string {
	if edid == nil {
		return ""
	}
	return fmt.Sprintf("%s-%d", edid.ManufacturerId, edid.ProductCode)
}

// Raw EDID bytes.
func (edid *EDID) Bytes() []byte {
	if edid == nil {
		return nil
	}
	return edid.bytes
}

// Whether EDID matches a target EDID. False if either are nil.
func (edid *EDID) Matches(target *EDID) bool {
	if edid == nil || target == nil {
		return false
	}
	return Matches(*edid, *target)
}

// Parses EDID from byte data.
func NewFromBytes(bytes []byte) (*EDID, error) {
	edid, err := edid.NewEdid(bytes)
	if err != nil {
		return nil, fmt.Errorf("failed to parse EDID data: %w", err)
	}
	return &EDID{
		Edid:  edid,
		bytes: bytes,
	}, nil
}

// Parses EDID from the byte data in the file.
func NewFromFile(path string) (*EDID, error) {
	bytes, err := os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("failed to read file %s: %w", path, err)
	}

	if string(bytes) == "" {
		return nil, fmt.Errorf("EDID file is empty")
	}

	return NewFromBytes(bytes)
}

// A and B match if they have the same (non-empty) manufacturer ID and product code.
func Matches(a, b EDID) bool {
	if a.ManufacturerId == "" || b.ManufacturerId == "" {
		return false
	} else if a.ManufacturerId != b.ManufacturerId {
		return false
	}

	if a.ProductCode == 0 || b.ProductCode == 0 {
		return false
	} else if a.ProductCode != b.ProductCode {
		return false
	}

	return true
}