// Package project 内的 repository.go 是 sqlc 生成层之上的薄包装：把
// pgtype.* 与领域类型互转，把 pgx.ErrNoRows 翻译成 errs.NotFound，把
// pg unique_violation（编号竞争）暴露为可识别的 error 让 service 决定重试。
package project

import (
	"context"
	"errors"
	"time"

	"github.com/google/uuid"
	"github.com/jackc/pgerrcode"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgconn"
	"github.com/jackc/pgx/v5/pgtype"
	"github.com/jackc/pgx/v5/pgxpool"

	"github.com/yan1h/agent-coding-workflow/internal/infra/errs"
	projectsqlc "github.com/yan1h/agent-coding-workflow/internal/project/sqlc"
)

// Repository 是 project 模块对 PG 的全部依赖。所有方法都接受 context 并返回
// 领域类型。Service 层的单元测试通过手写 fakeRepo 满足该接口。
type Repository interface {
	// Project
	CreateProject(ctx context.Context, p *Project) (*Project, error)
	GetProjectBySlug(ctx context.Context, slug string) (*Project, error)
	GetProjectByID(ctx context.Context, id uuid.UUID) (*Project, error)
	ListProjects(ctx context.Context, includeArchived bool) ([]*Project, error)
	UpdateProject(ctx context.Context, p *Project) (*Project, error)
	ArchiveProject(ctx context.Context, id uuid.UUID) error
	UnarchiveProject(ctx context.Context, id uuid.UUID) error

	// Requirement
	CreateRequirement(ctx context.Context, r *Requirement) (*Requirement, error)
	GetRequirementByNumber(ctx context.Context, projectID uuid.UUID, number int) (*Requirement, error)
	GetRequirementByID(ctx context.Context, id uuid.UUID) (*Requirement, error)
	ListRequirements(ctx context.Context, projectID uuid.UUID, phase Phase, status Status) ([]*Requirement, error)
	UpdateRequirement(ctx context.Context, r *Requirement) (*Requirement, error)
	UpdateRequirementPhase(ctx context.Context, id uuid.UUID, to Phase) (*Requirement, error)
	CloseRequirement(ctx context.Context, id uuid.UUID) error
	ReopenRequirement(ctx context.Context, id uuid.UUID) error

	// Issue
	CreateIssue(ctx context.Context, i *Issue) (*Issue, error)
	GetIssueByNumber(ctx context.Context, projectID uuid.UUID, number int) (*Issue, error)
	ListIssues(ctx context.Context, projectID uuid.UUID, filter IssueFilter, requirementID *uuid.UUID) ([]*Issue, error)
	ListIssuesByRequirement(ctx context.Context, requirementID uuid.UUID) ([]*Issue, error)
	UpdateIssueCore(ctx context.Context, id uuid.UUID, title, description string, requirementID *uuid.UUID) (*Issue, error)
	UpdateIssueAssignee(ctx context.Context, id uuid.UUID, assignee *uuid.UUID) (*Issue, error)
	CloseIssue(ctx context.Context, id uuid.UUID) error
	ReopenIssue(ctx context.Context, id uuid.UUID) error
}

// IsUniqueViolation 报告 err 是否为 PG 唯一约束冲突。Service 层在 Create*
// 时碰到此 error 会重试 1 次（编号自增竞争）。
func IsUniqueViolation(err error) bool {
	var pg *pgconn.PgError
	return errors.As(err, &pg) && pg.Code == pgerrcode.UniqueViolation
}

type pgRepo struct{ q *projectsqlc.Queries }

// NewPostgresRepository 用现有的 pgxpool 构造 Repository。
func NewPostgresRepository(pool *pgxpool.Pool) Repository {
	return &pgRepo{q: projectsqlc.New(pool)}
}

// ===== 类型转换 helper =====

func toPgUUID(u uuid.UUID) pgtype.UUID { return pgtype.UUID{Bytes: u, Valid: true} }
func toPgUUIDPtr(u *uuid.UUID) pgtype.UUID {
	if u == nil {
		return pgtype.UUID{Valid: false}
	}
	return pgtype.UUID{Bytes: *u, Valid: true}
}
func fromPgUUID(p pgtype.UUID) uuid.UUID {
	if !p.Valid {
		return uuid.Nil
	}
	return uuid.UUID(p.Bytes)
}
func fromPgUUIDPtr(p pgtype.UUID) *uuid.UUID {
	if !p.Valid {
		return nil
	}
	u := uuid.UUID(p.Bytes)
	return &u
}
func fromPgTimePtr(t pgtype.Timestamptz) *time.Time {
	if !t.Valid {
		return nil
	}
	v := t.Time
	return &v
}

// ===== Project =====

func rowToProject(row projectsqlc.Project) *Project {
	return &Project{
		ID:          fromPgUUID(row.ID),
		Slug:        row.Slug,
		Name:        row.Name,
		Description: row.Description,
		Visibility:  Visibility(row.Visibility),
		OwnerID:     fromPgUUID(row.OwnerID),
		ArchivedAt:  fromPgTimePtr(row.ArchivedAt),
		CreatedAt:   row.CreatedAt.Time,
		UpdatedAt:   row.UpdatedAt.Time,
	}
}

func (r *pgRepo) CreateProject(ctx context.Context, p *Project) (*Project, error) {
	row, err := r.q.CreateProject(ctx, projectsqlc.CreateProjectParams{
		ID:          toPgUUID(p.ID),
		Slug:        p.Slug,
		Name:        p.Name,
		Description: p.Description,
		Visibility:  string(p.Visibility),
		OwnerID:     toPgUUID(p.OwnerID),
	})
	if err != nil {
		if IsUniqueViolation(err) {
			return nil, errs.New(errs.CodeProjectSlugTaken, "slug 已被使用")
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "create project")
	}
	return rowToProject(row), nil
}

func (r *pgRepo) GetProjectBySlug(ctx context.Context, slug string) (*Project, error) {
	row, err := r.q.GetProjectBySlug(ctx, slug)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, errs.New(errs.CodeNotFound, "project 不存在")
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "get project by slug")
	}
	return rowToProject(row), nil
}

func (r *pgRepo) GetProjectByID(ctx context.Context, id uuid.UUID) (*Project, error) {
	row, err := r.q.GetProjectByID(ctx, toPgUUID(id))
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, errs.New(errs.CodeNotFound, "project 不存在")
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "get project by id")
	}
	return rowToProject(row), nil
}

func (r *pgRepo) ListProjects(ctx context.Context, includeArchived bool) ([]*Project, error) {
	rows, err := r.q.ListProjects(ctx, includeArchived)
	if err != nil {
		return nil, errs.Wrap(err, errs.CodeInternal, "list projects")
	}
	out := make([]*Project, 0, len(rows))
	for _, row := range rows {
		out = append(out, rowToProject(row))
	}
	return out, nil
}

func (r *pgRepo) UpdateProject(ctx context.Context, p *Project) (*Project, error) {
	row, err := r.q.UpdateProject(ctx, projectsqlc.UpdateProjectParams{
		ID:          toPgUUID(p.ID),
		Name:        p.Name,
		Description: p.Description,
		Visibility:  string(p.Visibility),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, errs.New(errs.CodeNotFound, "project 不存在")
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "update project")
	}
	return rowToProject(row), nil
}

func (r *pgRepo) ArchiveProject(ctx context.Context, id uuid.UUID) error {
	if err := r.q.ArchiveProject(ctx, toPgUUID(id)); err != nil {
		return errs.Wrap(err, errs.CodeInternal, "archive project")
	}
	return nil
}

func (r *pgRepo) UnarchiveProject(ctx context.Context, id uuid.UUID) error {
	if err := r.q.UnarchiveProject(ctx, toPgUUID(id)); err != nil {
		return errs.Wrap(err, errs.CodeInternal, "unarchive project")
	}
	return nil
}

// ===== Requirement =====

func rowToRequirement(row projectsqlc.Requirement) *Requirement {
	return &Requirement{
		ID:          fromPgUUID(row.ID),
		ProjectID:   fromPgUUID(row.ProjectID),
		Number:      int(row.Number),
		Title:       row.Title,
		Description: row.Description,
		Phase:       Phase(row.Phase),
		Status:      Status(row.Status),
		OwnerID:     fromPgUUID(row.OwnerID),
		ClosedAt:    fromPgTimePtr(row.ClosedAt),
		CreatedAt:   row.CreatedAt.Time,
		UpdatedAt:   row.UpdatedAt.Time,
	}
}

func (r *pgRepo) CreateRequirement(ctx context.Context, in *Requirement) (*Requirement, error) {
	row, err := r.q.CreateRequirement(ctx, projectsqlc.CreateRequirementParams{
		ID:          toPgUUID(in.ID),
		ProjectID:   toPgUUID(in.ProjectID),
		Title:       in.Title,
		Description: in.Description,
		OwnerID:     toPgUUID(in.OwnerID),
	})
	if err != nil {
		if IsUniqueViolation(err) {
			return nil, err // service 层据此重试一次
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "create requirement")
	}
	return rowToRequirement(row), nil
}

func (r *pgRepo) GetRequirementByNumber(ctx context.Context, projectID uuid.UUID, number int) (*Requirement, error) {
	row, err := r.q.GetRequirementByNumber(ctx, projectsqlc.GetRequirementByNumberParams{
		ProjectID: toPgUUID(projectID),
		Number:    int32(number),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, errs.New(errs.CodeNotFound, "requirement 不存在")
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "get requirement by number")
	}
	return rowToRequirement(row), nil
}

func (r *pgRepo) GetRequirementByID(ctx context.Context, id uuid.UUID) (*Requirement, error) {
	row, err := r.q.GetRequirementByID(ctx, toPgUUID(id))
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, errs.New(errs.CodeNotFound, "requirement 不存在")
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "get requirement by id")
	}
	return rowToRequirement(row), nil
}

func (r *pgRepo) ListRequirements(ctx context.Context, projectID uuid.UUID, phase Phase, status Status) ([]*Requirement, error) {
	var phasePtr, statusPtr *string
	if phase != "" {
		s := string(phase)
		phasePtr = &s
	}
	if status != "" {
		s := string(status)
		statusPtr = &s
	}
	rows, err := r.q.ListRequirements(ctx, projectsqlc.ListRequirementsParams{
		ProjectID: toPgUUID(projectID),
		Phase:     phasePtr,
		Status:    statusPtr,
	})
	if err != nil {
		return nil, errs.Wrap(err, errs.CodeInternal, "list requirements")
	}
	out := make([]*Requirement, 0, len(rows))
	for _, row := range rows {
		out = append(out, rowToRequirement(row))
	}
	return out, nil
}

func (r *pgRepo) UpdateRequirement(ctx context.Context, in *Requirement) (*Requirement, error) {
	row, err := r.q.UpdateRequirement(ctx, projectsqlc.UpdateRequirementParams{
		ID:          toPgUUID(in.ID),
		Title:       in.Title,
		Description: in.Description,
		OwnerID:     toPgUUID(in.OwnerID),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, errs.New(errs.CodeNotFound, "requirement 不存在")
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "update requirement")
	}
	return rowToRequirement(row), nil
}

func (r *pgRepo) UpdateRequirementPhase(ctx context.Context, id uuid.UUID, to Phase) (*Requirement, error) {
	row, err := r.q.UpdateRequirementPhase(ctx, projectsqlc.UpdateRequirementPhaseParams{
		ID:    toPgUUID(id),
		Phase: string(to),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, errs.New(errs.CodeNotFound, "requirement 不存在")
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "update requirement phase")
	}
	return rowToRequirement(row), nil
}

func (r *pgRepo) CloseRequirement(ctx context.Context, id uuid.UUID) error {
	if err := r.q.CloseRequirement(ctx, toPgUUID(id)); err != nil {
		return errs.Wrap(err, errs.CodeInternal, "close requirement")
	}
	return nil
}

func (r *pgRepo) ReopenRequirement(ctx context.Context, id uuid.UUID) error {
	if err := r.q.ReopenRequirement(ctx, toPgUUID(id)); err != nil {
		return errs.Wrap(err, errs.CodeInternal, "reopen requirement")
	}
	return nil
}

// ===== Issue =====

func rowToIssue(row projectsqlc.Issue) *Issue {
	return &Issue{
		ID:            fromPgUUID(row.ID),
		ProjectID:     fromPgUUID(row.ProjectID),
		RequirementID: fromPgUUIDPtr(row.RequirementID),
		Number:        int(row.Number),
		Title:         row.Title,
		Description:   row.Description,
		Status:        Status(row.Status),
		AssigneeID:    fromPgUUIDPtr(row.AssigneeID),
		CreatedBy:     fromPgUUID(row.CreatedBy),
		ClosedAt:      fromPgTimePtr(row.ClosedAt),
		CreatedAt:     row.CreatedAt.Time,
		UpdatedAt:     row.UpdatedAt.Time,
	}
}

func (r *pgRepo) CreateIssue(ctx context.Context, in *Issue) (*Issue, error) {
	row, err := r.q.CreateIssue(ctx, projectsqlc.CreateIssueParams{
		ID:            toPgUUID(in.ID),
		ProjectID:     toPgUUID(in.ProjectID),
		RequirementID: toPgUUIDPtr(in.RequirementID),
		Title:         in.Title,
		Description:   in.Description,
		AssigneeID:    toPgUUIDPtr(in.AssigneeID),
		CreatedBy:     toPgUUID(in.CreatedBy),
	})
	if err != nil {
		if IsUniqueViolation(err) {
			return nil, err
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "create issue")
	}
	return rowToIssue(row), nil
}

func (r *pgRepo) GetIssueByNumber(ctx context.Context, projectID uuid.UUID, number int) (*Issue, error) {
	row, err := r.q.GetIssueByNumber(ctx, projectsqlc.GetIssueByNumberParams{
		ProjectID: toPgUUID(projectID),
		Number:    int32(number),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, errs.New(errs.CodeNotFound, "issue 不存在")
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "get issue by number")
	}
	return rowToIssue(row), nil
}

func (r *pgRepo) ListIssues(ctx context.Context, projectID uuid.UUID, filter IssueFilter, requirementID *uuid.UUID) ([]*Issue, error) {
	var statusPtr, reqFilter *string
	if filter.Status != "" {
		s := string(filter.Status)
		statusPtr = &s
	}
	switch {
	case filter.Requirement == nil:
		reqFilter = nil
	case *filter.Requirement == 0:
		s := "none"
		reqFilter = &s
	default:
		s := "id"
		reqFilter = &s
	}
	rows, err := r.q.ListIssues(ctx, projectsqlc.ListIssuesParams{
		ProjectID:         toPgUUID(projectID),
		Status:            statusPtr,
		RequirementFilter: reqFilter,
		RequirementID:     toPgUUIDPtr(requirementID),
		AssigneeID:        toPgUUIDPtr(filter.AssigneeID),
	})
	if err != nil {
		return nil, errs.Wrap(err, errs.CodeInternal, "list issues")
	}
	out := make([]*Issue, 0, len(rows))
	for _, row := range rows {
		out = append(out, rowToIssue(row))
	}
	return out, nil
}

func (r *pgRepo) ListIssuesByRequirement(ctx context.Context, requirementID uuid.UUID) ([]*Issue, error) {
	rows, err := r.q.ListIssuesByRequirement(ctx, toPgUUID(requirementID))
	if err != nil {
		return nil, errs.Wrap(err, errs.CodeInternal, "list issues by requirement")
	}
	out := make([]*Issue, 0, len(rows))
	for _, row := range rows {
		out = append(out, rowToIssue(row))
	}
	return out, nil
}

func (r *pgRepo) UpdateIssueCore(ctx context.Context, id uuid.UUID, title, description string, requirementID *uuid.UUID) (*Issue, error) {
	row, err := r.q.UpdateIssueCore(ctx, projectsqlc.UpdateIssueCoreParams{
		ID:            toPgUUID(id),
		Title:         title,
		Description:   description,
		RequirementID: toPgUUIDPtr(requirementID),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, errs.New(errs.CodeNotFound, "issue 不存在")
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "update issue core")
	}
	return rowToIssue(row), nil
}

func (r *pgRepo) UpdateIssueAssignee(ctx context.Context, id uuid.UUID, assignee *uuid.UUID) (*Issue, error) {
	row, err := r.q.UpdateIssueAssignee(ctx, projectsqlc.UpdateIssueAssigneeParams{
		ID:         toPgUUID(id),
		AssigneeID: toPgUUIDPtr(assignee),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, errs.New(errs.CodeNotFound, "issue 不存在")
		}
		return nil, errs.Wrap(err, errs.CodeInternal, "update issue assignee")
	}
	return rowToIssue(row), nil
}

func (r *pgRepo) CloseIssue(ctx context.Context, id uuid.UUID) error {
	if err := r.q.CloseIssue(ctx, toPgUUID(id)); err != nil {
		return errs.Wrap(err, errs.CodeInternal, "close issue")
	}
	return nil
}

func (r *pgRepo) ReopenIssue(ctx context.Context, id uuid.UUID) error {
	if err := r.q.ReopenIssue(ctx, toPgUUID(id)); err != nil {
		return errs.Wrap(err, errs.CodeInternal, "reopen issue")
	}
	return nil
}