package importer

import (
	"bufio"
	"bytes"
	"context"
	"fmt"
	"io"
	"math"
	"os"
	"strings"

	"github.com/urfave/cli/v2"

	"git.gabrielgio.me/dict/db"
)

var ImportCommand = &cli.Command{
	Name:  "import",
	Usage: "convert dict.cc dictionary into a queryable sqlite format.",
	Flags: []cli.Flag{
		&cli.StringFlag{
			Name:  "output",
			Value: "main.dict",
			Usage: "Dictionary database location",
		},
		&cli.StringFlag{
			Name:  "input",
			Value: "dict.txt",
			Usage: "Dict.cc txt dictionary file",
		},
	},
	Action: func(cCtx *cli.Context) error {
		input := cCtx.String("input")
		output := cCtx.String("output")
		return Import(context.Background(), input, output)
	},
}

func Import(ctx context.Context, txtInput, sqliteOutput string) error {
	db, err := db.Open(":memory:")
	if err != nil {
		return err
	}
	err = db.Migrate(ctx)
	if err != nil {
		return err
	}

	file, err := os.Open(txtInput)
	if err != nil {
		return err
	}
	defer file.Close()

	count := 0
	total, err := lineCounter(file)
	if err != nil {
		return err
	}

	_, err = file.Seek(0, 0)
	if err != nil {
		return err
	}

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		if strings.HasPrefix(scanner.Text(), "#") || scanner.Text() == "" {
			continue
		}

		var (
			p    = strings.SplitN(scanner.Text(), "\t", 2)
			word = p[0]
			line = strings.ReplaceAll(p[1], "\t", " ")
		)

		if err := db.InsertLine(ctx, word, line); err != nil {
			return err
		}
		count++

		if (count % 1234) == 0 {
			fmt.Print("\033[G\033[K") // move the cursor left and clear the line
			per := math.Ceil((float64(count) / float64(total)) * 100.0)
			fmt.Printf("%d/%d (%.0f%%)", count, total, per)
		}
	}

	fmt.Printf("Consolidating")
	err = db.Consolidade(ctx)
	if err != nil {
		return err
	}

	err = db.Backup(ctx, sqliteOutput)
	if err != nil {
		return err
	}
	return nil
}

func lineCounter(r io.Reader) (int, error) {
	var count int
	const lineBreak = '\n'

	buf := make([]byte, bufio.MaxScanTokenSize)

	for {
		bufferSize, err := r.Read(buf)
		if err != nil && err != io.EOF {
			return 0, err
		}

		var buffPosition int
		for {
			i := bytes.IndexByte(buf[buffPosition:], lineBreak)
			if i == -1 || bufferSize == buffPosition {
				break
			}
			buffPosition += i + 1
			count++
		}
		if err == io.EOF {
			break
		}
	}

	return count, nil
}