package sqlite

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

	"inbox/internal/domain/taskgraph"
)

func (s *Store) CreateTaskGraphVersion(ctx context.Context, value taskgraph.Record) (taskgraph.Record, error) {
	if err := value.Validate(); err != nil {
		return taskgraph.Record{}, err
	}
	if value.ID == "" {
		id, err := s.newID("task-graph-version")
		if err != nil {
			return taskgraph.Record{}, err
		}
		value.ID = id
	}
	value.CreatedAt = coalesceString(value.CreatedAt, s.now())
	if _, err := s.db.ExecContext(ctx, `
		INSERT INTO task_graph_versions(
			id, topic_id, version, status, plan_json, plan_summary_markdown,
			created_by_role_name, created_at, confirmed_at, supersedes_graph_version_id
		)
		VALUES(?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
	`,
		value.ID,
		value.TopicID,
		value.Version,
		string(value.Status),
		value.PlanJSON,
		value.PlanSummaryMarkdown,
		value.CreatedByRoleName,
		value.CreatedAt,
		nullableString(value.ConfirmedAt),
		nullableString(value.SupersedesGraphVersionID),
	); err != nil {
		return taskgraph.Record{}, fmt.Errorf("create task graph version: %w", err)
	}
	return value, nil
}

func (s *Store) GetTaskGraphVersion(ctx context.Context, graphVersionID string) (taskgraph.Record, error) {
	row := s.db.QueryRowContext(ctx, `
		SELECT id, topic_id, version, status, plan_json, plan_summary_markdown,
		       created_by_role_name, created_at, confirmed_at, supersedes_graph_version_id
		FROM task_graph_versions
		WHERE id = ?
	`, graphVersionID)
	return scanTaskGraphVersion(row)
}

func (s *Store) ListTaskGraphVersionsByTopic(ctx context.Context, topicID string) ([]taskgraph.Record, error) {
	rows, err := s.db.QueryContext(ctx, `
		SELECT id, topic_id, version, status, plan_json, plan_summary_markdown,
		       created_by_role_name, created_at, confirmed_at, supersedes_graph_version_id
		FROM task_graph_versions
		WHERE topic_id = ?
		ORDER BY version DESC, created_at DESC
	`, topicID)
	if err != nil {
		return nil, fmt.Errorf("list task graph versions by topic: %w", err)
	}
	defer rows.Close()

	var out []taskgraph.Record
	for rows.Next() {
		item, err := scanTaskGraphVersion(rows)
		if err != nil {
			return nil, err
		}
		out = append(out, item)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("iterate task graph versions: %w", err)
	}
	return out, nil
}

func (s *Store) GetLatestTaskGraphVersionByTopic(ctx context.Context, topicID string) (taskgraph.Record, error) {
	row := s.db.QueryRowContext(ctx, `
		SELECT id, topic_id, version, status, plan_json, plan_summary_markdown,
		       created_by_role_name, created_at, confirmed_at, supersedes_graph_version_id
		FROM task_graph_versions
		WHERE topic_id = ?
		ORDER BY version DESC, created_at DESC
		LIMIT 1
	`, topicID)
	return scanTaskGraphVersion(row)
}

func (s *Store) UpdateTaskGraphVersion(ctx context.Context, value taskgraph.Record) (taskgraph.Record, error) {
	if value.ID == "" {
		return taskgraph.Record{}, fmt.Errorf("task graph version id is required")
	}
	before, err := s.GetTaskGraphVersion(ctx, value.ID)
	if err != nil {
		return taskgraph.Record{}, err
	}
	value.TopicID = before.TopicID
	value.Version = before.Version
	value.CreatedAt = before.CreatedAt
	if err := value.Validate(); err != nil {
		return taskgraph.Record{}, err
	}
	if _, err := s.db.ExecContext(ctx, `
		UPDATE task_graph_versions
		SET status = ?, plan_json = ?, plan_summary_markdown = ?, created_by_role_name = ?,
		    confirmed_at = ?, supersedes_graph_version_id = ?
		WHERE id = ?
	`,
		string(value.Status),
		value.PlanJSON,
		value.PlanSummaryMarkdown,
		value.CreatedByRoleName,
		nullableString(value.ConfirmedAt),
		nullableString(value.SupersedesGraphVersionID),
		value.ID,
	); err != nil {
		return taskgraph.Record{}, fmt.Errorf("update task graph version: %w", err)
	}
	return s.GetTaskGraphVersion(ctx, value.ID)
}

func scanTaskGraphVersion(s scanner) (taskgraph.Record, error) {
	var item taskgraph.Record
	var status string
	var confirmedAt sql.NullString
	var supersedesID sql.NullString
	if err := s.Scan(
		&item.ID,
		&item.TopicID,
		&item.Version,
		&status,
		&item.PlanJSON,
		&item.PlanSummaryMarkdown,
		&item.CreatedByRoleName,
		&item.CreatedAt,
		&confirmedAt,
		&supersedesID,
	); err != nil {
		return taskgraph.Record{}, err
	}
	item.Status = taskgraph.Status(status)
	if confirmedAt.Valid {
		item.ConfirmedAt = confirmedAt.String
	}
	if supersedesID.Valid {
		item.SupersedesGraphVersionID = supersedesID.String
	}
	return item, nil
}