package main

import (
	"bufio"
	"database/sql"
	"fmt"
	"html/template"
	"log"
	"os"
	"strings"

	"github.com/goccy/go-json"
)

func setupDatabase() (*sql.DB, error) {
	db, err := sql.Open("sqlite3", dictionary)
	if err != nil {
		return nil, fmt.Errorf("opening DB '%s': %s", dictionary, err)
	}

	_, err = db.Exec("create table IF NOT EXISTS words (word text not null, definition text);")
	if err != nil {
		return nil, fmt.Errorf("creating table: %s", err)
	}

	row := db.QueryRow(`SELECT count(*) as count from words`)
	var count int
	err = row.Scan(&count)
	if err != nil {
		return nil, fmt.Errorf("counting rows: %s", err)
	}

	// Only populate the database if it is empty.
	if count > 0 {
		return db, nil
	}

	// Faster import performance.
	_, err = db.Exec("PRAGMA synchronous = OFF;")
	if err != nil {
		return nil, fmt.Errorf("setting risky writes: %s", err)
	}

	if err = populateDictionary(db); err != nil {
		return nil, fmt.Errorf("failed to prepare dictionary: %s", err)
	}
	return db, nil
}

type rawDictionaryEntry struct {
	Word      string   `json:"word"`
	LangCode  string   `json:"lang_code"`
	POS       string   `json:"pos_title"`
	Etymology []string `json:"etymology_texts"`
	Senses    []sense  `json:"senses"`
	Sounds    []sound  `json:"sounds"`
	Tags      []string `json:"tags"`
}

type sense struct {
	Glosses  []string  `json:"glosses"`
	Examples []example `json:"examples"`
}

type example struct {
	Text string `json:"text"`
}

type sound struct {
	IPA string `json:"ipa"`
}

type templateReadyDictionaryEntry struct {
	Word      string
	POS       string
	Etymology string
	Senses    []SenseForDictionaryEntry
	Sound     string
	Gender    string
}

type SenseForDictionaryEntry struct {
	Sense   string
	Example string
}

func populateDictionary(db *sql.DB) error {
	log.Printf("preparing list of dictionary words...")

	// Set up the template
	tmpl, err := template.New("entry").Parse(
		`<p>{{ .Word }} {{ .Sound }} <i>{{ .POS }} {{ .Gender }}</i></p>
<ol>{{ range .Senses}}
	<li>{{ .Sense }}<br>
	{{ if .Example }}
		<ul><li><i>{{ .Example }}</i></li></ul></li>
	{{ end }}
{{ end }}</ol>`)
	if err != nil {
		panic(err)
	}

	tx, err := db.Begin()
	if err != nil {
		return fmt.Errorf("starting transaction: %w", err)
	}

	// Set up a prepared statement
	stmt, err := tx.Prepare("insert into words(word, definition) values(?, ?)")
	if err != nil {
		return fmt.Errorf("preparing statement: %w", err)
	}
	defer stmt.Close()

	file, err := os.Open(rawDictionary)
	if err != nil {
		return fmt.Errorf("opening: %w", err)
	}
	defer file.Close()

	var wordsAdded int
	scanner := bufio.NewScanner(file)

	maxCapacity := 2_000_000
	buf := make([]byte, maxCapacity)
	scanner.Buffer(buf, maxCapacity)

	for scanner.Scan() {
		var result rawDictionaryEntry
		json.Unmarshal([]byte(scanner.Text()), &result)
		if result.LangCode != "fr" {
			continue
		}

		// Create the definition text.
		entry := templateReadyDictionaryEntry{
			Word: result.Word,
			POS:  strings.ToLower(result.POS),
		}
		if len(result.Etymology) > 0 {
			entry.Etymology = result.Etymology[0]
		}
		if len(result.Sounds) > 0 {
			entry.Sound = result.Sounds[0].IPA
		}
		for _, r := range result.Tags {
			var genders []string
			if r == "masculine" || r == "feminine" {
				genders = append(genders, r)
			}
			entry.Gender = strings.Join(genders, " / ")
		}
		for _, s := range result.Senses {
			var example string
			if len(s.Examples) > 0 {
				example = s.Examples[0].Text
			}
			sense := strings.Join(s.Glosses, "; ")
			entry.Senses = append(entry.Senses, SenseForDictionaryEntry{Sense: sense, Example: example})
		}

		formattedDefinition := strings.Builder{}
		err := tmpl.Execute(&formattedDefinition, entry)
		if err != nil {
			return fmt.Errorf("failed to render: %w", err)
		}

		// Insert the entry
		_, err = stmt.Exec(entry.Word, formattedDefinition.String())
		if err != nil {
			return fmt.Errorf("inserting '%s': %w", entry.Word, err)
		}

		wordsAdded++
		if wordsAdded%10_000 == 0 && wordsAdded > 1 {
			log.Printf("processed %d lines (most recent word was '%s')", wordsAdded, entry.Word)
		}

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

	if err := tx.Commit(); err != nil {
		return fmt.Errorf("committing: %w", err)
	}

	_, err = db.Exec("create index wordindex on words(word);")
	if err != nil {
		return fmt.Errorf("creating index: %s", err)
	}

	log.Printf("prepared %d dictionary entries", wordsAdded)

	return nil
}