//go:build darwin && !cgo

package platform

import (
	"fmt"
	"runtime"
	"strings"

	"gitgud.io/mike/mpv-manager/pkg/log"
)

func detectCodecSupportDarwin() ([]string, error) {
	if runtime.GOOS != "darwin" {
		return nil, fmt.Errorf("not running on macOS")
	}

	log.Info("Using model-based codec detection")
	return detectCodecSupportDarwinForGPU(detectGPUDarwin())
}

func detectCodecSupportDarwinForGPU(info *GPUInfo) ([]string, error) {
	if info == nil || len(info.Models) == 0 {
		// Probe failure is uncertainty, not evidence of AV1 support.
		return []string{"hevc", "avc"}, nil
	}

	cpuModel := strings.ToLower(info.Models[0])

	return getCodecsForModel(cpuModel)
}

func getCodecsForModel(cpuModel string) ([]string, error) {
	// Intel Macs report a GPU name (e.g. "Intel Iris Plus Graphics 655"), not
	// an Apple chip; they hardware-decode AVC and HEVC only. Check before the
	// Apple-silicon defaults so they don't falsely claim AV1.
	if strings.Contains(strings.ToLower(cpuModel), "intel") {
		return []string{"avc", "hevc"}, nil
	}

	modelNum := extractModelNumber(cpuModel)

	if strings.HasPrefix(modelNum, "m1") {
		return []string{"hevc", "avc", "prores"}, nil
	}

	if strings.HasPrefix(modelNum, "m2") {
		return []string{"hevc", "avc", "vp9", "prores"}, nil
	}

	if strings.HasPrefix(modelNum, "m3") {
		return []string{"hevc", "avc", "vp9", "av1", "prores"}, nil
	}

	if strings.HasPrefix(modelNum, "m4") {
		return []string{"hevc", "avc", "vp9", "av1", "prores"}, nil
	}

	if strings.HasPrefix(modelNum, "m5") {
		return []string{"hevc", "avc", "vp9", "av1", "prores"}, nil
	}

	// Unknown/future model strings fail conservatively. Runtime probing can
	// add newer codecs when it is available; a model parse failure must not.
	return []string{"hevc", "avc"}, nil
}

func extractModelNumber(cpuModel string) string {
	cpuModel = strings.ToLower(cpuModel)

	if strings.Contains(cpuModel, "m1") {
		return "m1"
	}
	if strings.Contains(cpuModel, "m2") {
		return "m2"
	}
	if strings.Contains(cpuModel, "m3") {
		return "m3"
	}
	if strings.Contains(cpuModel, "m4") {
		return "m4"
	}
	if strings.Contains(cpuModel, "m5") {
		return "m5"
	}

	return ""
}