/* Copyright (C) 2019, 2020, 2021, 2022, 2023, 2024, 2025 Dnote contributors
 *
 * This file is part of Dnote.
 *
 * Dnote is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Dnote is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Dnote.  If not, see <https://www.gnu.org/licenses/>.
 */

// Command schema generates the CLI database schema.sql file.
package main

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

	"github.com/dnote/dnote/pkg/cli/config"
	"github.com/dnote/dnote/pkg/cli/context"
	"github.com/dnote/dnote/pkg/cli/database"
	"github.com/dnote/dnote/pkg/cli/infra"
	"github.com/dnote/dnote/pkg/cli/migrate"
)

func main() {
	tmpDir, err := os.MkdirTemp("", "dnote-schema-gen-*")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
		os.Exit(1)
	}
	defer os.RemoveAll(tmpDir)

	schemaPath := filepath.Join("pkg", "cli", "database", "schema.sql")

	if err := run(tmpDir, schemaPath); err != nil {
		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
		os.Exit(1)
	}
}

func run(tmpDir, outputPath string) error {
	schema, err := generateSchema(tmpDir)
	if err != nil {
		return err
	}

	if err := os.WriteFile(outputPath, []byte(schema), 0644); err != nil {
		return fmt.Errorf("writing schema file: %w", err)
	}

	fmt.Printf("Schema generated successfully at %s\n", outputPath)
	return nil
}

// generateSchema creates a fresh database, runs all migrations, and extracts the schema
func generateSchema(tmpDir string) (string, error) {
	// Create dnote directory structure in temp dir
	dnoteDir := filepath.Join(tmpDir, "dnote")
	if err := os.MkdirAll(dnoteDir, 0755); err != nil {
		return "", fmt.Errorf("creating dnote dir: %w", err)
	}

	// Use a file-based database
	dbPath := filepath.Join(tmpDir, "schema.db")

	// Create context
	ctx := context.DnoteCtx{
		Paths: context.Paths{
			Home:   tmpDir,
			Config: tmpDir,
			Data:   tmpDir,
			Cache:  tmpDir,
		},
		Version: "schema-gen",
	}

	// Open database
	db, err := database.Open(dbPath)
	if err != nil {
		return "", fmt.Errorf("opening database: %w", err)
	}
	defer db.Close()
	ctx.DB = db

	// Initialize database with base tables
	if err := infra.InitDB(ctx); err != nil {
		return "", fmt.Errorf("initializing database: %w", err)
	}

	// Initialize system data
	if err := infra.InitSystem(ctx); err != nil {
		return "", fmt.Errorf("initializing system: %w", err)
	}

	// Create minimal config file
	if err := config.Write(ctx, config.Config{}); err != nil {
		return "", fmt.Errorf("writing initial config: %w", err)
	}

	// Run all local migrations
	if err := migrate.Run(ctx, migrate.LocalSequence, migrate.LocalMode); err != nil {
		return "", fmt.Errorf("running migrations: %w", err)
	}

	// Extract schema before closing database
	schema, err := extractSchema(db)
	if err != nil {
		return "", fmt.Errorf("extracting schema: %w", err)
	}

	return schema, nil
}

// extractSchema extracts the complete schema by querying sqlite_master
func extractSchema(db *database.DB) (string, error) {
	// Query sqlite_master for all schema objects, excluding FTS shadow tables
	// FTS shadow tables are internal tables automatically created by FTS virtual tables
	rows, err := db.Conn.Query(`SELECT sql FROM sqlite_master
		WHERE sql IS NOT NULL
		AND name NOT LIKE 'sqlite_%'
		AND (type != 'table'
		OR (type = 'table' AND name NOT IN (
			SELECT m1.name FROM sqlite_master m1
			JOIN sqlite_master m2 ON m1.name LIKE m2.name || '_%'
			WHERE m2.type = 'table' AND m2.sql LIKE '%VIRTUAL TABLE%'
		)))`)
	if err != nil {
		return "", fmt.Errorf("querying sqlite_master: %w", err)
	}
	defer rows.Close()

	var schemas []string
	for rows.Next() {
		var sql string
		if err := rows.Scan(&sql); err != nil {
			return "", fmt.Errorf("scanning row: %w", err)
		}
		schemas = append(schemas, sql)
	}

	if err := rows.Err(); err != nil {
		return "", fmt.Errorf("iterating rows: %w", err)
	}

	// Add autogenerated header comment
	header := `-- This is the final state of the CLI database after all migrations.
-- Auto-generated by generate-schema.go. Do not edit manually.
`
	return header + strings.Join(schemas, ";\n") + ";\n", nil
}