package genmodels

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

	"gorm.io/gen"
	"gorm.io/gen/field"
	"gorm.io/gorm"
)

const GENERATED_FILES_FOLDER = "./app/model/prestadb"
const GENERATED_MODEL_PKG = "prestadb"

type GormGenModels struct {
	db *gorm.DB
}

func New(db *gorm.DB) *GormGenModels {
	return &GormGenModels{
		db: db,
	}
}

func (m *GormGenModels) GormGenModels(ctx context.Context) error {
	// Use gorm gen to generate models
	g := gen.NewGenerator(gen.Config{
		OutPath:      GENERATED_FILES_FOLDER,
		ModelPkgPath: GENERATED_MODEL_PKG,
		Mode:         gen.WithoutContext,
	})

	g.UseDB(m.db)

	// Get all table names from the database and filter for 'ps_' prefix
	tableNames, err := m.db.Migrator().GetTables()
	if err != nil {
		return fmt.Errorf("failed to get table list: %w", err)
	}

	// Generate models only for tables with 'ps_' prefix
	// Use gen.FieldRelateModel to add foreign key relations
	for _, tableName := range tableNames {
		if strings.HasPrefix(tableName, "ps_") {
			g.GenerateModel(tableName, gen.FieldRelateModel(field.BelongsTo, "*", nil, &field.RelateConfig{}))
		}
	}

	g.Execute()

	// Post-process: remove query/DO files and keep only model files
	if err := m.cleanupGeneratedFiles(); err != nil {
		return fmt.Errorf("failed to cleanup generated files: %w", err)
	}

	return nil
}

func (m *GormGenModels) cleanupGeneratedFiles() error {
	// Files to remove (query/DO code)
	filesToRemove := []string{
		"gen.go",
		"do.go",
		"_gen.go",
	}

	// Directory to clean
	dir := GENERATED_FILES_FOLDER
	if !strings.HasPrefix(dir, "./") {
		dir = "./" + dir
	}

	// Get absolute path if needed
	absDir, err := filepath.Abs(dir)
	if err != nil {
		return err
	}

	// Remove query files
	for _, fileName := range filesToRemove {
		filePath := filepath.Join(absDir, fileName)
		if _, err := os.Stat(filePath); err == nil {
			if err := os.Remove(filePath); err != nil {
				return fmt.Errorf("failed to remove %s: %w", filePath, err)
			}
			fmt.Printf("Removed: %s\n", filePath)
		}
	}

	// Rename ps_*.gen.go to *.go (e.g., ps_category.gen.go -> category.go)
	files, err := os.ReadDir(absDir)
	if err != nil {
		return err
	}

	for _, file := range files {
		name := file.Name()
		// Check if it's a generated model file like ps_category.gen.go
		if strings.HasSuffix(name, ".gen.go") && strings.HasPrefix(name, "ps_") {
			oldPath := filepath.Join(absDir, name)
			// Extract name: ps_category.gen.go -> category
			baseName := strings.TrimSuffix(name, ".gen.go")
			baseName, _ = strings.CutPrefix(baseName, "ps_")
			newPath := filepath.Join(absDir, baseName+".go")

			// Read file content
			content, err := os.ReadFile(oldPath)
			if err != nil {
				return err
			}

			// Remove package prestadb imports that reference generated DO
			// and clean up the code
			content = m.cleanModelContent(content)

			// Write to new file
			if err := os.WriteFile(newPath, content, 0644); err != nil {
				return err
			}

			// Remove old file
			if err := os.Remove(oldPath); err != nil {
				return err
			}

			fmt.Printf("Renamed: %s -> %s\n", oldPath, newPath)
		}
	}

	return nil
}

func (m *GormGenModels) cleanModelContent(content []byte) []byte {
	result := string(content)

	// Remove imports that are only needed for query code
	// Keep "gorm.io/gorm/schema" for TableName method
	lines := strings.Split(result, "\n")
	var newLines []string
	importStarted := false
	importEnded := false

	for _, line := range lines {
		trimmed := strings.TrimSpace(line)

		// Track import block
		if trimmed == "import (" {
			importStarted = true
			newLines = append(newLines, line)
			continue
		}
		if importStarted && trimmed == ")" {
			importEnded = true
			importStarted = false
			newLines = append(newLines, line)
			continue
		}

		// Inside import block, remove query-related imports
		if importStarted && !importEnded {
			// Skip these imports as they're only for query code
			if strings.Contains(trimmed, "\"gorm.io/gen\"") ||
				strings.Contains(trimmed, "\"gorm.io/gen/field\"") ||
				strings.Contains(trimmed, "\"gorm.io/plugin/dbresolver\"") ||
				strings.Contains(trimmed, "gen.DO") {
				continue
			}
		}

		// Remove DO (Data Object) type definitions
		if strings.Contains(trimmed, "type psCategoryDo struct") ||
			strings.HasPrefix(trimmed, "func (p psCategoryDo)") {
			continue
		}

		newLines = append(newLines, line)
	}

	result = strings.Join(newLines, "\n")

	// Also remove the psCategoryDo references in methods
	result = strings.ReplaceAll(result, "psCategoryDo", "")

	return []byte(result)
}