package repository

import (
	"context"
	"errors"

	dbgen "Yimaru-Backend/gen/db"
	"Yimaru-Backend/internal/domain"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgtype"
)

func int64PtrToPg8(p *int64) pgtype.Int8 {
	if p == nil {
		return pgtype.Int8{Valid: false}
	}
	return pgtype.Int8{Int64: *p, Valid: true}
}

func fromPgInt8ID(c pgtype.Int8) *int64 {
	if !c.Valid {
		return nil
	}
	v := c.Int64
	return &v
}

func lmsPracticeToDomain(p dbgen.LmsPractice) domain.Practice {
	out := domain.Practice{
		ID:            p.ID,
		Title:         p.Title,
		QuestionSetID: p.QuestionSetID,
	}
	if p.CourseID.Valid {
		out.ParentKind = domain.ParentKindCourse
		out.ParentID = p.CourseID.Int64
	} else if p.ModuleID.Valid {
		out.ParentKind = domain.ParentKindModule
		out.ParentID = p.ModuleID.Int64
	} else if p.LessonID.Valid {
		out.ParentKind = domain.ParentKindLesson
		out.ParentID = p.LessonID.Int64
	}
	out.StoryDescription = fromPgText(p.StoryDescription)
	out.StoryImage = fromPgText(p.StoryImage)
	out.QuickTips = fromPgText(p.QuickTips)
	out.PersonaID = fromPgInt8ID(p.PersonaID)
	out.CreatedAt = p.CreatedAt.Time
	if p.UpdatedAt.Valid {
		t := p.UpdatedAt.Time
		out.UpdatedAt = &t
	}
	return out
}

func lmsFromListRow(
	id, qid int64, title string,
	cid, mid, lid pgtype.Int8,
	sd, si, qt pgtype.Text, pid pgtype.Int8,
	ca, ua pgtype.Timestamptz,
) domain.Practice {
	return lmsPracticeToDomain(dbgen.LmsPractice{
		ID:               id,
		CourseID:         cid,
		ModuleID:         mid,
		LessonID:         lid,
		Title:            title,
		StoryDescription: sd,
		StoryImage:       si,
		PersonaID:        pid,
		QuestionSetID:    qid,
		QuickTips:        qt,
		CreatedAt:        ca,
		UpdatedAt:        ua,
	})
}

// CreateLmsPractice sets exactly one of courseID, moduleID, lessonID (non-nil).
func (s *Store) CreateLmsPractice(
	ctx context.Context,
	in domain.CreatePracticeInput,
	courseID, moduleID, lessonID *int64,
) (domain.Practice, error) {
	p, err := s.queries.CreateLmsPractice(ctx, dbgen.CreateLmsPracticeParams{
		CourseID:         int64PtrToPg8(courseID),
		ModuleID:         int64PtrToPg8(moduleID),
		LessonID:         int64PtrToPg8(lessonID),
		Title:            in.Title,
		StoryDescription: toPgText(in.StoryDescription),
		StoryImage:       toPgText(in.StoryImage),
		PersonaID:        int64PtrToPg8(in.PersonaID),
		QuestionSetID:    in.QuestionSetID,
		QuickTips:        toPgText(in.QuickTips),
	})
	if err != nil {
		return domain.Practice{}, err
	}
	return lmsPracticeToDomain(p), nil
}

func (s *Store) GetLmsPracticeByID(ctx context.Context, id int64) (domain.Practice, error) {
	p, err := s.queries.GetLmsPracticeByID(ctx, id)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return domain.Practice{}, pgx.ErrNoRows
		}
		return domain.Practice{}, err
	}
	return lmsPracticeToDomain(p), nil
}

func (s *Store) ListLmsPracticesByCourseID(ctx context.Context, courseID int64, limit, offset int32) ([]domain.Practice, int64, error) {
	rows, err := s.queries.ListLmsPracticesByCourseID(ctx, dbgen.ListLmsPracticesByCourseIDParams{
		CourseID: pgtype.Int8{Int64: courseID, Valid: true},
		Limit:    limit,
		Offset:   offset,
	})
	if err != nil {
		return nil, 0, err
	}
	if len(rows) == 0 {
		return []domain.Practice{}, 0, nil
	}
	var total int64
	out := make([]domain.Practice, 0, len(rows))
	for i, r := range rows {
		if i == 0 {
			total = r.TotalCount
		}
		out = append(out, lmsFromListRow(
			r.ID, r.QuestionSetID, r.Title,
			r.CourseID, r.ModuleID, r.LessonID,
			r.StoryDescription, r.StoryImage, r.QuickTips,
			r.PersonaID, r.CreatedAt, r.UpdatedAt,
		))
	}
	return out, total, nil
}

func (s *Store) ListLmsPracticesByModuleID(ctx context.Context, moduleID int64, limit, offset int32) ([]domain.Practice, int64, error) {
	rows, err := s.queries.ListLmsPracticesByModuleID(ctx, dbgen.ListLmsPracticesByModuleIDParams{
		ModuleID: pgtype.Int8{Int64: moduleID, Valid: true},
		Limit:    limit,
		Offset:   offset,
	})
	if err != nil {
		return nil, 0, err
	}
	if len(rows) == 0 {
		return []domain.Practice{}, 0, nil
	}
	var total int64
	out := make([]domain.Practice, 0, len(rows))
	for i, r := range rows {
		if i == 0 {
			total = r.TotalCount
		}
		out = append(out, lmsFromListRow(
			r.ID, r.QuestionSetID, r.Title,
			r.CourseID, r.ModuleID, r.LessonID,
			r.StoryDescription, r.StoryImage, r.QuickTips,
			r.PersonaID, r.CreatedAt, r.UpdatedAt,
		))
	}
	return out, total, nil
}

func (s *Store) ListLmsPracticesByLessonID(ctx context.Context, lessonID int64, limit, offset int32) ([]domain.Practice, int64, error) {
	rows, err := s.queries.ListLmsPracticesByLessonID(ctx, dbgen.ListLmsPracticesByLessonIDParams{
		LessonID: pgtype.Int8{Int64: lessonID, Valid: true},
		Limit:    limit,
		Offset:   offset,
	})
	if err != nil {
		return nil, 0, err
	}
	if len(rows) == 0 {
		return []domain.Practice{}, 0, nil
	}
	var total int64
	out := make([]domain.Practice, 0, len(rows))
	for i, r := range rows {
		if i == 0 {
			total = r.TotalCount
		}
		out = append(out, lmsFromListRow(
			r.ID, r.QuestionSetID, r.Title,
			r.CourseID, r.ModuleID, r.LessonID,
			r.StoryDescription, r.StoryImage, r.QuickTips,
			r.PersonaID, r.CreatedAt, r.UpdatedAt,
		))
	}
	return out, total, nil
}

func optionalInt8UpdateID(val *int64) pgtype.Int8 {
	if val == nil {
		return pgtype.Int8{Valid: false}
	}
	return pgtype.Int8{Int64: *val, Valid: true}
}

func (s *Store) UpdateLmsPractice(ctx context.Context, id int64, input domain.UpdatePracticeInput) (domain.Practice, error) {
	var titleText pgtype.Text
	if input.Title != nil {
		titleText = pgtype.Text{String: *input.Title, Valid: true}
	} else {
		titleText = pgtype.Text{Valid: false}
	}
	qs := optionalInt8UpdateID(input.QuestionSetID)
	p, err := s.queries.UpdateLmsPractice(ctx, dbgen.UpdateLmsPracticeParams{
		ID:               id,
		Title:            titleText,
		StoryDescription: optionalTextUpdate(input.StoryDescription),
		StoryImage:       optionalTextUpdate(input.StoryImage),
		PersonaID:        optionalInt8UpdateID(input.PersonaID),
		QuestionSetID:    qs,
		QuickTips:        optionalTextUpdate(input.QuickTips),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return domain.Practice{}, pgx.ErrNoRows
		}
		return domain.Practice{}, err
	}
	return lmsPracticeToDomain(p), nil
}

func (s *Store) DeleteLmsPractice(ctx context.Context, id int64) error {
	return s.queries.DeleteLmsPractice(ctx, id)
}