package main

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"time"

	_ "github.com/mattn/go-sqlite3"
)

const historyDBName = "history.db"

type EmailStatus string

const (
	StatusSent  EmailStatus = "sent"
	StatusDraft EmailStatus = "draft"
)

type EmailHistory struct {
	ID             int64
	From           string
	To             string
	Cc             string
	Bcc            string
	Subject        string
	BodyText       string
	BodyHTML       string
	Attachments    string
	Status         EmailStatus
	DeliveryMethod string
	CreatedAt      time.Time
	SentAt         *time.Time
}

func getHistoryDBPath() (string, error) {
	configDir, err := getConfigDir()
	if err != nil {
		return "", err
	}
	return filepath.Join(configDir, historyDBName), nil
}

func initHistoryDB() (*sql.DB, error) {
	dbPath, err := getHistoryDBPath()
	if err != nil {
		return nil, err
	}

	db, err := sql.Open("sqlite3", dbPath)
	if err != nil {
		return nil, err
	}

	_, err = db.Exec(`
		CREATE TABLE IF NOT EXISTS emails (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			from_addr TEXT NOT NULL,
			to_addrs TEXT NOT NULL,
			cc_addrs TEXT,
			bcc_addrs TEXT,
			subject TEXT NOT NULL,
			body_text TEXT,
			body_html TEXT,
			attachments TEXT,
			status TEXT NOT NULL,
			delivery_method TEXT,
			created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
			sent_at DATETIME
		)
	`)
	if err != nil {
		return nil, err
	}

	return db, nil
}

func SaveEmail(from, to, cc, bcc, subject, bodyText, bodyHTML, attachments, deliveryMethod string, status EmailStatus) (int64, error) {
	db, err := initHistoryDB()
	if err != nil {
		return 0, err
	}
	defer db.Close()

	stmt, err := db.Prepare(`
		INSERT INTO emails (from_addr, to_addrs, cc_addrs, bcc_addrs, subject, body_text, body_html, attachments, status, delivery_method, created_at, sent_at)
		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
	`)
	if err != nil {
		return 0, err
	}
	defer stmt.Close()

	now := time.Now()
	var sentAt *time.Time
	if status == StatusSent {
		sentAt = &now
	}
	result, err := stmt.Exec(from, to, cc, bcc, subject, bodyText, bodyHTML, attachments, status, deliveryMethod, now, sentAt)
	if err != nil {
		return 0, err
	}

	return result.LastInsertId()
}

func UpdateEmailStatus(id int64, status EmailStatus) error {
	db, err := initHistoryDB()
	if err != nil {
		return err
	}
	defer db.Close()

	_, err = db.Exec("UPDATE emails SET status = ?, sent_at = ? WHERE id = ?", status, time.Now(), id)
	return err
}

func GetEmailHistory(status EmailStatus) ([]EmailHistory, error) {
	db, err := initHistoryDB()
	if err != nil {
		return nil, err
	}
	defer db.Close()

	var query string
	var args []interface{}

	if status == "" {
		query = "SELECT id, from_addr, to_addrs, cc_addrs, bcc_addrs, subject, body_text, body_html, attachments, status, delivery_method, created_at, sent_at FROM emails ORDER BY created_at DESC"
	} else {
		query = "SELECT id, from_addr, to_addrs, cc_addrs, bcc_addrs, subject, body_text, body_html, attachments, status, delivery_method, created_at, sent_at FROM emails WHERE status = ? ORDER BY created_at DESC"
		args = []interface{}{status}
	}

	rows, err := db.Query(query, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var histories []EmailHistory
	for rows.Next() {
		var h EmailHistory
		var sentAt sql.NullTime
		err := rows.Scan(&h.ID, &h.From, &h.To, &h.Cc, &h.Bcc, &h.Subject, &h.BodyText, &h.BodyHTML, &h.Attachments, &h.Status, &h.DeliveryMethod, &h.CreatedAt, &sentAt)
		if err != nil {
			return nil, err
		}
		if sentAt.Valid {
			h.SentAt = &sentAt.Time
		}
		histories = append(histories, h)
	}

	return histories, nil
}

func GetEmailByID(id int64) (*EmailHistory, error) {
	db, err := initHistoryDB()
	if err != nil {
		return nil, err
	}
	defer db.Close()

	var h EmailHistory
	var sentAt sql.NullTime
	err = db.QueryRow("SELECT id, from_addr, to_addrs, cc_addrs, bcc_addrs, subject, body_text, body_html, attachments, status, delivery_method, created_at, sent_at FROM emails WHERE id = ?", id).Scan(
		&h.ID, &h.From, &h.To, &h.Cc, &h.Bcc, &h.Subject, &h.BodyText, &h.BodyHTML, &h.Attachments, &h.Status, &h.DeliveryMethod, &h.CreatedAt, &sentAt,
	)
	if err != nil {
		return nil, err
	}
	if sentAt.Valid {
		h.SentAt = &sentAt.Time
	}
	return &h, nil
}

func DeleteEmailHistory(id int64) error {
	db, err := initHistoryDB()
	if err != nil {
		return err
	}
	defer db.Close()

	_, err = db.Exec("DELETE FROM emails WHERE id = ?", id)
	return err
}

func getAttachmentsJSON(paths []string) string {
	if len(paths) == 0 {
		return "[]"
	}
	data, _ := json.Marshal(paths)
	return string(data)
}

func parseAttachmentsJSON(jsonStr string) []string {
	if jsonStr == "" || jsonStr == "[]" {
		return nil
	}
	var paths []string
	json.Unmarshal([]byte(jsonStr), &paths)
	return paths
}

func init() {
	dbPath, err := getHistoryDBPath()
	if err != nil {
		return
	}
	if _, err := os.Stat(dbPath); os.IsNotExist(err) {
		if _, err := initHistoryDB(); err != nil {
			fmt.Fprintf(os.Stderr, "Failed to initialize history DB: %v\n", err)
		}
	}
}