package tui

import (
	"fmt"
	"os"
	"path/filepath"

	"dirmd/internal/config"
	"dirmd/internal/drive"
	"dirmd/internal/renderer"
	"dirmd/internal/walker"
)

type GenerateResult struct {
	Files    []string
	Uploaded bool
	Error    error
}

func Generate(cfg *config.Config) GenerateResult {
	result := GenerateResult{}

	abs, err := filepath.Abs(cfg.InputPath)
	if err != nil {
		result.Error = fmt.Errorf("resolve input path: %w", err)
		return result
	}
	cfg.AbsRoot = abs

	var outputBase string

	if cfg.AppendMode || cfg.SingleFile {
		absOutput, err := filepath.Abs(cfg.OutputPath)
		if err != nil {
			result.Error = fmt.Errorf("resolve output path: %w", err)
			return result
		}

		if !cfg.AppendMode {
			if _, err := os.Stat(absOutput); err == nil && !cfg.Force {
				result.Error = fmt.Errorf("output %s exists (enable force or append)", absOutput)
				return result
			}
		}

		dir := filepath.Dir(absOutput)
		if err := os.MkdirAll(dir, 0755); err != nil {
			result.Error = fmt.Errorf("create output dir: %w", err)
			return result
		}

		outputBase = absOutput
	} else {
		absOutput, err := filepath.Abs(cfg.OutputPath)
		if err != nil {
			result.Error = fmt.Errorf("resolve output path: %w", err)
			return result
		}
		absOutput = filepath.Join(filepath.Dir(absOutput), filepath.Base(absOutput)+"_dirmd")

		if !cfg.AppendMode {
			if _, err := os.Stat(absOutput); err == nil && !cfg.Force {
				result.Error = fmt.Errorf("output %s exists (enable force)", absOutput)
				return result
			}
		}

		if err := os.MkdirAll(absOutput, 0755); err != nil {
			result.Error = fmt.Errorf("create output dir: %w", err)
			return result
		}

		cfg.OutputPath = absOutput
		outputBase = absOutput
	}

	walkResult, err := walker.Run(cfg)
	if err != nil {
		result.Error = err
		return result
	}

	if len(walkResult.Entries) == 0 {
		result.Error = fmt.Errorf("no readable files in %s", cfg.AbsRoot)
		return result
	}

	repoName := filepath.Base(cfg.AbsRoot)

	if cfg.VerticalSlices {
		generated, err := renderer.WriteSlices(walkResult, cfg.OutputPath, repoName)
		if err != nil {
			result.Error = err
			return result
		}
		result.Files = generated
	} else {
		indexPath := cfg.OutputPath
		if err := renderer.Write(walkResult, indexPath, cfg.AppendMode, cfg.SingleFile); err != nil {
			result.Error = err
			return result
		}
		result.Files = []string{indexPath}
	}

	if cfg.ProtonDrive {
		remoteDir := cfg.DrivePath
		if remoteDir == "" {
			remoteDir = "/my-files/md/" + filepath.Base(outputBase)
		}

		if err := drive.CheckAuth(); err != nil {
			result.Error = fmt.Errorf("drive auth: %w", err)
			return result
		}

		if cfg.VerticalSlices {
			if err := drive.UploadDir(cfg.OutputPath, remoteDir); err != nil {
				result.Error = fmt.Errorf("drive upload: %w", err)
				return result
			}
		} else {
			indexPath := cfg.OutputPath
			if err := drive.Upload(indexPath, remoteDir); err != nil {
				result.Error = fmt.Errorf("drive upload: %w", err)
				return result
			}
		}
		result.Uploaded = true
	}

	return result
}