// Copyright (c) 2025-2026 Probo Inc <hello@getprobo.com>.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

package coredata

import (
	"context"
	"errors"
	"fmt"
	"time"

	"github.com/jackc/pgx/v5"
	"go.gearno.de/kit/pg"
	"go.probo.inc/probo/pkg/gid"
	"go.probo.inc/probo/pkg/mail"
)

type (
	Email struct {
		ID                  gid.GID     `db:"id"`
		RecipientEmail      string      `db:"recipient_email"`
		RecipientName       string      `db:"recipient_name"`
		SenderName          *string     `db:"sender_name"`
		ReplyTo             *mail.Addr  `db:"reply_to"`
		UnsubscribeURL      *string     `db:"unsubscribe_url"`
		MailingListUpdateID *gid.GID    `db:"mailing_list_update_id"`
		Subject             string      `db:"subject"`
		TextBody            string      `db:"text_body"`
		HtmlBody            *string     `db:"html_body"`
		Status              EmailStatus `db:"status"`
		ProcessingStartedAt *time.Time  `db:"processing_started_at"`
		AttemptCount        int         `db:"attempt_count"`
		MaxAttempts         int         `db:"max_attempts"`
		LastAttemptedAt     *time.Time  `db:"last_attempted_at"`
		LastError           *string     `db:"last_error"`
		CreatedAt           time.Time   `db:"created_at"`
		UpdatedAt           time.Time   `db:"updated_at"`
		SentAt              *time.Time  `db:"sent_at"`
	}

	Emails []*Email

	EmailOptions struct {
		SenderName          *string
		ReplyTo             *mail.Addr
		UnsubscribeURL      *string
		MailingListUpdateID *gid.GID
	}
)

var (
	ErrNoUnsentEmail = errors.New("no unsent email found")
)

// AuthorizationAttributes returns the authorization attributes for policy evaluation.
// Email is identity-scoped (not org-scoped), so it returns an empty map.
func (e *Email) AuthorizationAttributes(ctx context.Context, conn pg.Querier) (map[string]string, error) {
	return map[string]string{}, nil
}

func NewEmail(
	recipientName string,
	recipientEmail mail.Addr,
	subject string,
	textBody string,
	htmlBody *string,
	opts *EmailOptions,
) *Email {
	now := time.Now()
	e := &Email{
		ID:             gid.New(gid.NilTenant, EmailEntityType),
		RecipientName:  recipientName,
		RecipientEmail: recipientEmail.String(),
		Subject:        subject,
		TextBody:       textBody,
		HtmlBody:       htmlBody,
		Status:         EmailStatusPending,
		AttemptCount:   0,
		MaxAttempts:    10,
		CreatedAt:      now,
		UpdatedAt:      now,
	}

	if opts != nil {
		e.SenderName = opts.SenderName
		e.ReplyTo = opts.ReplyTo
		e.UnsubscribeURL = opts.UnsubscribeURL
		e.MailingListUpdateID = opts.MailingListUpdateID
	}

	return e
}

func (e *Email) Insert(
	ctx context.Context,
	conn pg.Tx,
) error {
	q := `
INSERT INTO emails (
	id,
	recipient_email,
	recipient_name,
	sender_name,
	reply_to,
	unsubscribe_url,
	mailing_list_update_id,
	subject,
	text_body,
	html_body,
	status,
	attempt_count,
	max_attempts,
	created_at,
	updated_at
)
VALUES (
	@id,
	@recipient_email,
	@recipient_name,
	@sender_name,
	@reply_to,
	@unsubscribe_url,
	@mailing_list_update_id,
	@subject,
	@text_body,
	@html_body,
	@status,
	@attempt_count,
	@max_attempts,
	@created_at,
	@updated_at
)
`

	args := pgx.StrictNamedArgs{
		"id":                     e.ID,
		"recipient_email":        e.RecipientEmail,
		"recipient_name":         e.RecipientName,
		"sender_name":            e.SenderName,
		"reply_to":               e.ReplyTo,
		"unsubscribe_url":        e.UnsubscribeURL,
		"mailing_list_update_id": e.MailingListUpdateID,
		"subject":                e.Subject,
		"text_body":              e.TextBody,
		"html_body":              e.HtmlBody,
		"status":                 e.Status,
		"attempt_count":          e.AttemptCount,
		"max_attempts":           e.MaxAttempts,
		"created_at":             e.CreatedAt,
		"updated_at":             e.UpdatedAt,
	}

	_, err := conn.Exec(ctx, q, args)
	return err
}

func (emails Emails) BulkInsert(
	ctx context.Context,
	conn pg.Querier,
) error {
	if len(emails) == 0 {
		return nil
	}

	rows := make([][]any, 0, len(emails))
	for _, e := range emails {
		rows = append(rows, []any{
			e.ID,
			e.RecipientEmail,
			e.RecipientName,
			e.SenderName,
			e.ReplyTo,
			e.UnsubscribeURL,
			e.MailingListUpdateID,
			e.Subject,
			e.TextBody,
			e.HtmlBody,
			e.CreatedAt,
			e.UpdatedAt,
		})
	}

	_, err := conn.CopyFrom(
		ctx,
		pgx.Identifier{"emails"},
		[]string{"id", "recipient_email", "recipient_name", "sender_name", "reply_to", "unsubscribe_url", "mailing_list_update_id", "subject", "text_body", "html_body", "created_at", "updated_at"},
		pgx.CopyFromRows(rows),
	)
	return err
}

func (e *Email) LoadNextPendingForUpdateSkipLocked(
	ctx context.Context,
	conn pg.Tx,
) error {
	q := `
SELECT
	id, recipient_email, recipient_name, sender_name, reply_to, unsubscribe_url, mailing_list_update_id, subject, text_body, html_body,
	status, processing_started_at, attempt_count, max_attempts,
	last_attempted_at, last_error, created_at, updated_at, sent_at
FROM emails
WHERE status = 'PENDING' AND attempt_count < max_attempts
ORDER BY created_at ASC
LIMIT 1
FOR UPDATE SKIP LOCKED
	`

	rows, err := conn.Query(ctx, q)
	if err != nil {
		return err
	}

	email, err := pgx.CollectExactlyOneRow(rows, pgx.RowToStructByName[Email])
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return ErrNoUnsentEmail
		}

		return fmt.Errorf("cannot collect email: %w", err)
	}

	*e = email

	return nil
}

func (e *Email) Update(
	ctx context.Context,
	conn pg.Tx,
) error {
	q := `
UPDATE emails
SET
	status = @status,
	processing_started_at = @processing_started_at,
	attempt_count = @attempt_count,
	last_attempted_at = @last_attempted_at,
	last_error = @last_error,
	sent_at = @sent_at,
	updated_at = @updated_at
WHERE id = @id
	`

	args := pgx.StrictNamedArgs{
		"id":                    e.ID,
		"status":                e.Status,
		"processing_started_at": e.ProcessingStartedAt,
		"attempt_count":         e.AttemptCount,
		"last_attempted_at":     e.LastAttemptedAt,
		"last_error":            e.LastError,
		"sent_at":               e.SentAt,
		"updated_at":            e.UpdatedAt,
	}

	_, err := conn.Exec(ctx, q, args)
	return err
}

func ResetStaleProcessingEmails(
	ctx context.Context,
	conn pg.Querier,
	staleAfter time.Duration,
) error {
	q := `
UPDATE emails
SET status = 'PENDING', processing_started_at = NULL, updated_at = NOW()
WHERE status = 'PROCESSING'
	AND processing_started_at < NOW() - $1::interval
`
	_, err := conn.Exec(ctx, q, staleAfter)
	if err != nil {
		return fmt.Errorf("cannot reset stale processing emails: %w", err)
	}

	return nil
}