package main

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"git.ipao.vip/rogee/creator-hub/internal/creator"
)

const maxCreatorMaterialBytes int64 = 512 << 20

func processCreatorMaterial(ctx context.Context, store *creator.Store, workID string) (creator.MaterialJob, error) {
	if store == nil || workID == "" || filepath.Base(workID) != workID {
		return creator.MaterialJob{}, creator.ErrInvalid
	}
	work, err := store.GetWork(ctx, workID)
	if err != nil {
		return creator.MaterialJob{}, err
	}
	job, err := store.GetMaterial(ctx, workID)
	if err != nil {
		return creator.MaterialJob{}, err
	}
	if !job.Selected {
		return creator.MaterialJob{}, creator.ErrConflict
	}
	root := os.Getenv("CREATOR_MEDIA_DIR")
	if root == "" {
		root = "/var/lib/creatorhub/materials"
	}
	root = filepath.Clean(root)
	dir := filepath.Join(root, workID)
	if err := os.MkdirAll(dir, 0o700); err != nil {
		return creator.MaterialJob{}, fmt.Errorf("create material directory: %w", err)
	}
	videoPath := filepath.Join(dir, "source")
	videoReference := filepath.Join(workID, "source")
	if job.DownloadStatus != "succeeded" || !fileExists(videoPath) {
		if _, err := store.SetMaterialStep(ctx, workID, "download", "running", "", ""); err != nil {
			return creator.MaterialJob{}, err
		}
		if err := downloadCreatorMaterial(ctx, work.OriginalURL, videoPath); err != nil {
			return setMaterialFailure(ctx, store, workID, "download", err)
		}
		job, err = store.SetMaterialStep(ctx, workID, "download", "succeeded", videoReference, "")
		if err != nil {
			return creator.MaterialJob{}, err
		}
	}

	audioPath := filepath.Join(dir, "audio.wav")
	audioReference := filepath.Join(workID, "audio.wav")
	if job.AudioStatus != "succeeded" && job.AudioStatus != "no_audio" {
		if _, err := store.SetMaterialStep(ctx, workID, "audio", "running", "", ""); err != nil {
			return creator.MaterialJob{}, err
		}
		hasAudio, err := creatorMaterialHasAudio(ctx, videoPath)
		if err != nil {
			return setMaterialFailure(ctx, store, workID, "audio", err)
		}
		if !hasAudio {
			job, err = store.SetMaterialStep(ctx, workID, "audio", "no_audio", "", "视频没有音轨")
			if err != nil {
				return creator.MaterialJob{}, err
			}
		} else if err := extractCreatorAudio(ctx, videoPath, audioPath); err != nil {
			return setMaterialFailure(ctx, store, workID, "audio", err)
		} else {
			job, err = store.SetMaterialStep(ctx, workID, "audio", "succeeded", audioReference, "")
			if err != nil {
				return creator.MaterialJob{}, err
			}
		}
	}

	if job.TranscriptionStatus != "succeeded" && job.TranscriptionStatus != "no_speech" {
		if job.AudioStatus == "no_audio" {
			job, err = store.SetMaterialStep(ctx, workID, "transcription", "no_speech", "", "没有可转写的音轨")
		} else {
			if _, err = store.SetMaterialStep(ctx, workID, "transcription", "running", "", ""); err == nil {
				transcript, transcribeErr := transcribeCreatorAudio(ctx, audioPath)
				if transcribeErr != nil {
					job, err = setMaterialFailure(ctx, store, workID, "transcription", transcribeErr)
				} else if strings.TrimSpace(transcript) == "" {
					job, err = store.SetMaterialStep(ctx, workID, "transcription", "no_speech", "", "转写未检测到语音")
				} else {
					transcriptPath := filepath.Join(dir, "transcript.txt")
					if writeErr := os.WriteFile(transcriptPath, []byte(transcript), 0o600); writeErr != nil {
						job, err = setMaterialFailure(ctx, store, workID, "transcription", writeErr)
					} else {
						job, err = store.SetMaterialStep(ctx, workID, "transcription", "succeeded", filepath.Join(workID, "transcript.txt"), "")
					}
				}
			}
		}
		if err != nil {
			return creator.MaterialJob{}, err
		}
	}
	return job, nil
}

func downloadCreatorMaterial(ctx context.Context, rawURL, destination string) error {
	parsed, err := http.NewRequestWithContext(ctx, http.MethodGet, rawURL, nil)
	if err != nil || (parsed.URL.Scheme != "http" && parsed.URL.Scheme != "https") || parsed.URL.Host == "" {
		return creator.ErrInvalid
	}
	client := &http.Client{Timeout: 2 * time.Minute}
	response, err := client.Do(parsed)
	if err != nil {
		return fmt.Errorf("download material: %w", err)
	}
	defer response.Body.Close()
	if response.StatusCode < 200 || response.StatusCode >= 300 {
		return fmt.Errorf("download material: HTTP %s", response.Status)
	}
	if response.ContentLength > maxCreatorMaterialBytes {
		return fmt.Errorf("download material exceeds size limit")
	}
	temporary := destination + ".tmp"
	defer os.Remove(temporary)
	file, err := os.OpenFile(temporary, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0o600)
	if err != nil {
		return fmt.Errorf("create material file: %w", err)
	}
	written, copyErr := io.Copy(file, io.LimitReader(response.Body, maxCreatorMaterialBytes+1))
	closeErr := file.Close()
	if copyErr != nil {
		return fmt.Errorf("write material: %w", copyErr)
	}
	if closeErr != nil {
		return fmt.Errorf("close material file: %w", closeErr)
	}
	if written > maxCreatorMaterialBytes {
		return fmt.Errorf("download material exceeds size limit")
	}
	if err := os.Rename(temporary, destination); err != nil {
		return fmt.Errorf("publish material: %w", err)
	}
	return nil
}

func creatorMaterialHasAudio(ctx context.Context, videoPath string) (bool, error) {
	if _, err := exec.LookPath("ffprobe"); err != nil {
		return false, fmt.Errorf("ffprobe is unavailable: %w", err)
	}
	command := exec.CommandContext(ctx, "ffprobe", "-v", "error", "-select_streams", "a:0", "-show_entries", "stream=index", "-of", "csv=p=0", videoPath)
	output, err := command.Output()
	if err != nil {
		return false, fmt.Errorf("inspect audio stream: %w", err)
	}
	return strings.TrimSpace(string(output)) != "", nil
}

func extractCreatorAudio(ctx context.Context, videoPath, audioPath string) error {
	if _, err := exec.LookPath("ffmpeg"); err != nil {
		return fmt.Errorf("ffmpeg is unavailable: %w", err)
	}
	temporary := audioPath + ".tmp"
	defer os.Remove(temporary)
	command := exec.CommandContext(ctx, "ffmpeg", "-nostdin", "-v", "error", "-y", "-i", videoPath, "-vn", "-ac", "1", "-ar", "16000", temporary)
	if output, err := command.CombinedOutput(); err != nil {
		return fmt.Errorf("extract audio: %w: %s", err, strings.TrimSpace(string(output)))
	}
	if !fileExists(temporary) {
		return fmt.Errorf("extract audio produced no file")
	}
	if err := os.Rename(temporary, audioPath); err != nil {
		return fmt.Errorf("publish audio: %w", err)
	}
	return nil
}

func transcribeCreatorAudio(ctx context.Context, audioPath string) (string, error) {
	binary := os.Getenv("CREATOR_TRANSCRIPTION_BIN")
	if binary == "" {
		return "", fmt.Errorf("transcription provider is not configured")
	}
	if _, err := exec.LookPath(binary); err != nil {
		return "", fmt.Errorf("transcription provider is unavailable: %w", err)
	}
	output, err := exec.CommandContext(ctx, binary, audioPath).Output()
	if err != nil {
		return "", fmt.Errorf("transcribe audio: %w", err)
	}
	if len(output) > 1<<20 {
		return "", fmt.Errorf("transcript exceeds size limit")
	}
	return string(output), nil
}

func setMaterialFailure(ctx context.Context, store *creator.Store, workID, step string, cause error) (creator.MaterialJob, error) {
	job, err := store.SetMaterialStep(ctx, workID, step, "failed", "", cause.Error())
	if err != nil {
		return creator.MaterialJob{}, fmt.Errorf("record %s failure: %w", step, err)
	}
	return job, nil
}

func fileExists(path string) bool {
	info, err := os.Stat(path)
	return err == nil && info.Mode().IsRegular() && info.Size() > 0
}