package main

import (
	"encoding/csv"
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"html"
	"log"
	"os"
	"path/filepath"
	"strings"

	"github.com/themoeway/jmdict-go"
)

type (
	StoryEntry struct {
		Author        string `json:"author"`
		Content       string `json:"content"`
		ModifiedDate  string `json:"modifiedDate"`
		StarredCount  int    `json:"starredCount"`
		ReportedCount int    `json:"reportedCount"`
	}

	KanjiEntry struct {
		Character   string       `json:"character"`
		Reading     string       `json:"reading"`
		FrameNumber int          `json:"frameNumber"`
		StrokeCount int          `json:"strokeCount"`
		Story       string       `json:"story"`
		Stories     []StoryEntry `json:"stories"`
	}

	TableRow = []string
	Table    = []TableRow
)

func wrapSpan(content, class string) string {
	return fmt.Sprintf("<span class='%s'>%s</span>", class, html.EscapeString(content))
}

func injectStories(table Table, path string, heisigIndex int) error {
	fp, err := os.Open(path)
	if err != nil {
		return err
	}
	defer fp.Close()

	decoder := json.NewDecoder(fp)

	var characters []KanjiEntry
	if err := decoder.Decode(&characters); err != nil {
		return err
	}

	for i, row := range table {
		for _, character := range characters {
			if character.Character != row[heisigIndex] {
				continue
			}

			var stories strings.Builder
			for _, story := range character.Stories {
				content := strings.ReplaceAll(story.Content, "\n", " ")
				stories.WriteString(wrapSpan(content, "rtk-story"))
			}

			row = append(row, stories.String())
			table[i] = row
		}
	}

	return nil
}

func injectKanjidic(table Table, path string, heisigIndex int) error {
	fp, err := os.Open(path)
	if err != nil {
		return err
	}
	defer fp.Close()

	kd, err := jmdict.LoadKanjidic(fp)
	if err != nil {
		return err
	}

	for i, row := range table {
		var found bool
		for _, character := range kd.Characters {
			if character.Literal != row[heisigIndex] {
				continue
			}

			var (
				meanings strings.Builder
				kunyomi  strings.Builder
				onyomi   strings.Builder
			)

			for _, reading := range character.ReadingMeaning.Readings {
				switch reading.Type {
				case "ja_on":
					onyomi.WriteString(wrapSpan(reading.Value, "rtk-onyomi"))
				case "ja_kun":
					kunyomi.WriteString(wrapSpan(reading.Value, "rtk-kunyomi"))
				}
			}

			for _, meaning := range character.ReadingMeaning.Meanings {
				if meaning.Language == nil {
					meanings.WriteString(wrapSpan(meaning.Meaning, "rtk-meaning"))
				}
			}

			row = append(row, meanings.String())
			row = append(row, kunyomi.String())
			row = append(row, onyomi.String())

			table[i] = row
			found = true
		}

		if !found {
			return errors.New("character not found")
		}
	}

	return nil
}

func loadTable(path string, heisigIndex, columnLimit int) (Table, error) {
	fp, err := os.Open(path)
	if err != nil {
		return nil, err
	}
	defer fp.Close()

	reader := csv.NewReader(fp)
	reader.Comment = '#'
	reader.Comma = '\t'

	table, err := reader.ReadAll()
	if err != nil {
		return nil, err
	}

	for i := range table {
		table[i] = table[i][:columnLimit]
		if len(table[i]) < heisigIndex {
			return nil, errors.New("unexpected heisig index")
		}
	}

	return table, nil
}

func saveTable(path string, table Table) error {
	fp, err := os.Create(path)
	if err != nil {
		return err
	}
	defer fp.Close()

	writer := csv.NewWriter(fp)
	writer.Comma = '\t'
	if err := writer.WriteAll(table); err != nil {
		return err
	}

	return nil
}

func main() {
	var (
		storiesPath  = flag.String("stories", "", "path for stories JSON")
		kanjidicPath = flag.String("kanjidic", "", "path for KANJIDIC")
		heisigIndex  = flag.Int("heisig", 0, "heisig index column index")
		columnLimit  = flag.Int("columns", 3, "column trim value")
	)

	flag.Usage = func() {
		fmt.Fprintf(os.Stderr, "Usage: %s [options] <notes_in.txt> <notes_out.txt>\n", filepath.Base(os.Args[0]))
		fmt.Fprintln(os.Stderr, "Options:")
		flag.PrintDefaults()
	}

	flag.Parse()

	args := flag.Args()
	if len(args) != 2 {
		flag.Usage()
		os.Exit(2)
	}

	table, err := loadTable(args[0], *heisigIndex, *columnLimit)
	if err != nil {
		log.Fatal(err)
	}

	if len(*kanjidicPath) > 0 {
		if err := injectKanjidic(table, *kanjidicPath, *heisigIndex); err != nil {
			log.Fatal(err)
		}
	}

	if len(*storiesPath) > 0 {
		if err := injectStories(table, *storiesPath, *heisigIndex); err != nil {
			log.Fatal(err)
		}
	}

	if err := saveTable(args[1], table); err != nil {
		log.Fatal(err)
	}
}