package store

import (
	"context"
	"database/sql"
	"fmt"
	"strings"
	"time"

	"plumber/internal/store/sqlc"
)

// DiscordLink is the bot-owned mapping from a site post to a Discord message.
type DiscordLink struct {
	PostID    string
	MessageID string
	ThreadID  string
	CreatedAt string
}

// DiscordLinkStore is the mapping table used only by the Discord subscriber.
// It is not part of Store.
type DiscordLinkStore interface {
	GetByPostID(ctx context.Context, postID string) (*DiscordLink, error)
	GetByMessageID(ctx context.Context, messageID string) (*DiscordLink, error)
	GetRootByThreadID(ctx context.Context, threadID string) (*DiscordLink, error)
	Upsert(ctx context.Context, link DiscordLink) error
}

// DiscordLinks implements DiscordLinkStore against Postgres.
type DiscordLinks struct {
	db *sql.DB
}

// NewDiscordLinks wraps db. It is independent of Store.
func NewDiscordLinks(db *sql.DB) *DiscordLinks {
	return &DiscordLinks{db: db}
}

// GetByPostID returns the link for a site post.
func (d *DiscordLinks) GetByPostID(ctx context.Context, postID string) (*DiscordLink, error) {
	if d == nil || d.db == nil {
		return nil, fmt.Errorf("discord links: no database")
	}
	row, err := sqlc.New(d.db).GetDiscordPostLinkByPostID(ctx, strings.TrimSpace(postID))
	if err != nil {
		return nil, err
	}
	return discordLinkFromRow(row), nil
}

// GetByMessageID returns the link for a Discord message.
func (d *DiscordLinks) GetByMessageID(ctx context.Context, messageID string) (*DiscordLink, error) {
	if d == nil || d.db == nil {
		return nil, fmt.Errorf("discord links: no database")
	}
	row, err := sqlc.New(d.db).GetDiscordPostLinkByMessageID(ctx, strings.TrimSpace(messageID))
	if err != nil {
		return nil, err
	}
	return discordLinkFromRow(row), nil
}

// GetRootByThreadID returns the root link for a Discord thread.
func (d *DiscordLinks) GetRootByThreadID(ctx context.Context, threadID string) (*DiscordLink, error) {
	if d == nil || d.db == nil {
		return nil, fmt.Errorf("discord links: no database")
	}
	row, err := sqlc.New(d.db).GetDiscordPostLinkByThreadID(ctx, strings.TrimSpace(threadID))
	if err != nil {
		return nil, err
	}
	return discordLinkFromRow(row), nil
}

// Upsert inserts or replaces the Discord IDs for a post.
func (d *DiscordLinks) Upsert(ctx context.Context, link DiscordLink) error {
	if d == nil || d.db == nil {
		return fmt.Errorf("discord links: no database")
	}
	link.PostID = strings.TrimSpace(link.PostID)
	link.MessageID = strings.TrimSpace(link.MessageID)
	link.ThreadID = strings.TrimSpace(link.ThreadID)
	if link.PostID == "" || link.MessageID == "" {
		return fmt.Errorf("discord links: post and message ids are required")
	}
	if link.CreatedAt == "" {
		link.CreatedAt = time.Now().UTC().Format(time.RFC3339Nano)
	}
	return sqlc.New(d.db).UpsertDiscordPostLink(ctx, sqlc.UpsertDiscordPostLinkParams{
		PostID:           link.PostID,
		DiscordMessageID: link.MessageID,
		DiscordThreadID:  link.ThreadID,
		CreatedAt:        link.CreatedAt,
	})
}

func discordLinkFromRow(row sqlc.DiscordPostLink) *DiscordLink {
	return &DiscordLink{
		PostID:    row.PostID,
		MessageID: row.DiscordMessageID,
		ThreadID:  row.DiscordThreadID,
		CreatedAt: row.CreatedAt,
	}
}