// Package orchestrator implements multi-phase university crawling with queue management
package orchestrator

import (
	"context"
	"encoding/json"
	"fmt"
	"time"

	"github.com/google/uuid"
)

// Audience represents a target audience filter configuration
type Audience struct {
	ID              uuid.UUID        `json:"id"`
	Name            string           `json:"name"`
	Description     string           `json:"description,omitempty"`
	Filters         AudienceFilters  `json:"filters"`
	MemberCount     int              `json:"member_count"`
	LastCountUpdate *time.Time       `json:"last_count_update,omitempty"`
	CreatedBy       string           `json:"created_by,omitempty"`
	IsActive        bool             `json:"is_active"`
	CreatedAt       time.Time        `json:"created_at"`
	UpdatedAt       time.Time        `json:"updated_at"`
}

// AudienceFilters defines the filter criteria for an audience
type AudienceFilters struct {
	PositionTypes []string    `json:"position_types,omitempty"` // professor, researcher, lecturer
	SubjectAreas  []uuid.UUID `json:"subject_areas,omitempty"`  // Subject area UUIDs
	States        []string    `json:"states,omitempty"`         // BW, BY, etc.
	UniTypes      []string    `json:"uni_types,omitempty"`      // UNI, PH, HAW
	Universities  []uuid.UUID `json:"universities,omitempty"`   // University UUIDs
	HasEmail      *bool       `json:"has_email,omitempty"`
	IsActive      *bool       `json:"is_active,omitempty"`
	Keywords      []string    `json:"keywords,omitempty"` // Keywords in name/research
}

// AudienceExport tracks exports of audience data
type AudienceExport struct {
	ID          uuid.UUID  `json:"id"`
	AudienceID  uuid.UUID  `json:"audience_id"`
	ExportType  string     `json:"export_type"` // csv, json, email_list
	RecordCount int        `json:"record_count"`
	FilePath    string     `json:"file_path,omitempty"`
	ExportedBy  string     `json:"exported_by,omitempty"`
	Purpose     string     `json:"purpose,omitempty"`
	CreatedAt   time.Time  `json:"created_at"`
}

// AudienceMember represents a staff member in an audience preview
type AudienceMember struct {
	ID             uuid.UUID `json:"id"`
	Name           string    `json:"name"`
	Email          string    `json:"email,omitempty"`
	Position       string    `json:"position,omitempty"`
	University     string    `json:"university"`
	Department     string    `json:"department,omitempty"`
	SubjectArea    string    `json:"subject_area,omitempty"`
	PublicationCount int     `json:"publication_count"`
}

// AudienceRepository extends Repository with audience operations
type AudienceRepository interface {
	// Audience CRUD
	CreateAudience(ctx context.Context, audience *Audience) error
	GetAudience(ctx context.Context, id uuid.UUID) (*Audience, error)
	ListAudiences(ctx context.Context, activeOnly bool) ([]Audience, error)
	UpdateAudience(ctx context.Context, audience *Audience) error
	DeleteAudience(ctx context.Context, id uuid.UUID) error

	// Audience members
	GetAudienceMembers(ctx context.Context, id uuid.UUID, limit, offset int) ([]AudienceMember, int, error)
	UpdateAudienceCount(ctx context.Context, id uuid.UUID) (int, error)

	// Exports
	CreateExport(ctx context.Context, export *AudienceExport) error
	ListExports(ctx context.Context, audienceID uuid.UUID) ([]AudienceExport, error)
}

// ============================================================================
// POSTGRES IMPLEMENTATION
// ============================================================================

// CreateAudience creates a new audience
func (r *PostgresRepository) CreateAudience(ctx context.Context, audience *Audience) error {
	filtersJSON, err := json.Marshal(audience.Filters)
	if err != nil {
		return fmt.Errorf("failed to marshal filters: %w", err)
	}

	query := `
		INSERT INTO audiences (name, description, filters, created_by, is_active)
		VALUES ($1, $2, $3, $4, $5)
		RETURNING id, member_count, created_at, updated_at
	`

	return r.pool.QueryRow(ctx, query,
		audience.Name,
		audience.Description,
		filtersJSON,
		audience.CreatedBy,
		audience.IsActive,
	).Scan(&audience.ID, &audience.MemberCount, &audience.CreatedAt, &audience.UpdatedAt)
}

// GetAudience retrieves an audience by ID
func (r *PostgresRepository) GetAudience(ctx context.Context, id uuid.UUID) (*Audience, error) {
	query := `
		SELECT id, name, description, filters, member_count, last_count_update,
		       created_by, is_active, created_at, updated_at
		FROM audiences
		WHERE id = $1
	`

	var audience Audience
	var filtersJSON []byte

	err := r.pool.QueryRow(ctx, query, id).Scan(
		&audience.ID, &audience.Name, &audience.Description, &filtersJSON,
		&audience.MemberCount, &audience.LastCountUpdate,
		&audience.CreatedBy, &audience.IsActive,
		&audience.CreatedAt, &audience.UpdatedAt,
	)
	if err != nil {
		return nil, err
	}

	if err := json.Unmarshal(filtersJSON, &audience.Filters); err != nil {
		return nil, fmt.Errorf("failed to unmarshal filters: %w", err)
	}

	return &audience, nil
}

// ListAudiences lists all audiences
func (r *PostgresRepository) ListAudiences(ctx context.Context, activeOnly bool) ([]Audience, error) {
	query := `
		SELECT id, name, description, filters, member_count, last_count_update,
		       created_by, is_active, created_at, updated_at
		FROM audiences
	`
	if activeOnly {
		query += ` WHERE is_active = TRUE`
	}
	query += ` ORDER BY created_at DESC`

	rows, err := r.pool.Query(ctx, query)
	if err != nil {
		return nil, fmt.Errorf("failed to query audiences: %w", err)
	}
	defer rows.Close()

	var audiences []Audience
	for rows.Next() {
		var audience Audience
		var filtersJSON []byte

		if err := rows.Scan(
			&audience.ID, &audience.Name, &audience.Description, &filtersJSON,
			&audience.MemberCount, &audience.LastCountUpdate,
			&audience.CreatedBy, &audience.IsActive,
			&audience.CreatedAt, &audience.UpdatedAt,
		); err != nil {
			return nil, fmt.Errorf("failed to scan audience: %w", err)
		}

		if err := json.Unmarshal(filtersJSON, &audience.Filters); err != nil {
			return nil, fmt.Errorf("failed to unmarshal filters: %w", err)
		}

		audiences = append(audiences, audience)
	}

	return audiences, rows.Err()
}

// UpdateAudience updates an existing audience
func (r *PostgresRepository) UpdateAudience(ctx context.Context, audience *Audience) error {
	filtersJSON, err := json.Marshal(audience.Filters)
	if err != nil {
		return fmt.Errorf("failed to marshal filters: %w", err)
	}

	query := `
		UPDATE audiences
		SET name = $2, description = $3, filters = $4, is_active = $5, updated_at = NOW()
		WHERE id = $1
		RETURNING updated_at
	`

	return r.pool.QueryRow(ctx, query,
		audience.ID,
		audience.Name,
		audience.Description,
		filtersJSON,
		audience.IsActive,
	).Scan(&audience.UpdatedAt)
}

// DeleteAudience soft-deletes an audience (sets is_active = false)
func (r *PostgresRepository) DeleteAudience(ctx context.Context, id uuid.UUID) error {
	query := `UPDATE audiences SET is_active = FALSE, updated_at = NOW() WHERE id = $1`
	_, err := r.pool.Exec(ctx, query, id)
	return err
}

// GetAudienceMembers retrieves members matching the audience filters
func (r *PostgresRepository) GetAudienceMembers(ctx context.Context, id uuid.UUID, limit, offset int) ([]AudienceMember, int, error) {
	// First get the audience filters
	audience, err := r.GetAudience(ctx, id)
	if err != nil {
		return nil, 0, fmt.Errorf("failed to get audience: %w", err)
	}

	// Build dynamic query based on filters
	query, args := r.buildAudienceMemberQuery(audience.Filters, limit, offset, false)
	countQuery, countArgs := r.buildAudienceMemberQuery(audience.Filters, 0, 0, true)

	// Get total count
	var totalCount int
	if err := r.pool.QueryRow(ctx, countQuery, countArgs...).Scan(&totalCount); err != nil {
		return nil, 0, fmt.Errorf("failed to count members: %w", err)
	}

	// Get members
	rows, err := r.pool.Query(ctx, query, args...)
	if err != nil {
		return nil, 0, fmt.Errorf("failed to query members: %w", err)
	}
	defer rows.Close()

	var members []AudienceMember
	for rows.Next() {
		var m AudienceMember
		if err := rows.Scan(
			&m.ID, &m.Name, &m.Email, &m.Position,
			&m.University, &m.Department, &m.SubjectArea, &m.PublicationCount,
		); err != nil {
			return nil, 0, fmt.Errorf("failed to scan member: %w", err)
		}
		members = append(members, m)
	}

	return members, totalCount, rows.Err()
}

// buildAudienceMemberQuery constructs a SQL query for audience members
func (r *PostgresRepository) buildAudienceMemberQuery(filters AudienceFilters, limit, offset int, countOnly bool) (string, []interface{}) {
	var args []interface{}
	argNum := 1

	var selectClause string
	if countOnly {
		selectClause = "SELECT COUNT(*)"
	} else {
		selectClause = `
			SELECT
				s.id,
				COALESCE(s.title || ' ', '') || s.first_name || ' ' || s.last_name as name,
				COALESCE(s.email, '') as email,
				COALESCE(s.position_type, '') as position,
				u.name as university,
				COALESCE(d.name, '') as department,
				COALESCE(sa.name, '') as subject_area,
				(SELECT COUNT(*) FROM staff_publications sp WHERE sp.staff_id = s.id) as publication_count
		`
	}

	query := selectClause + `
		FROM university_staff s
		JOIN universities u ON s.university_id = u.id
		LEFT JOIN departments d ON s.department_id = d.id
		LEFT JOIN subject_areas sa ON s.subject_area_id = sa.id
		WHERE 1=1
	`

	// Position types filter
	if len(filters.PositionTypes) > 0 {
		query += fmt.Sprintf(" AND s.position_type = ANY($%d)", argNum)
		args = append(args, filters.PositionTypes)
		argNum++
	}

	// Subject areas filter
	if len(filters.SubjectAreas) > 0 {
		query += fmt.Sprintf(" AND s.subject_area_id = ANY($%d)", argNum)
		args = append(args, filters.SubjectAreas)
		argNum++
	}

	// States filter
	if len(filters.States) > 0 {
		query += fmt.Sprintf(" AND u.state = ANY($%d)", argNum)
		args = append(args, filters.States)
		argNum++
	}

	// Uni types filter
	if len(filters.UniTypes) > 0 {
		query += fmt.Sprintf(" AND u.uni_type = ANY($%d)", argNum)
		args = append(args, filters.UniTypes)
		argNum++
	}

	// Universities filter
	if len(filters.Universities) > 0 {
		query += fmt.Sprintf(" AND s.university_id = ANY($%d)", argNum)
		args = append(args, filters.Universities)
		argNum++
	}

	// Has email filter
	if filters.HasEmail != nil && *filters.HasEmail {
		query += " AND s.email IS NOT NULL AND s.email != ''"
	}

	// Is active filter
	if filters.IsActive != nil && *filters.IsActive {
		query += " AND s.is_active = TRUE"
	}

	// Keywords filter (search in name and research_areas)
	if len(filters.Keywords) > 0 {
		for _, keyword := range filters.Keywords {
			query += fmt.Sprintf(" AND (s.first_name ILIKE $%d OR s.last_name ILIKE $%d OR s.research_areas ILIKE $%d)", argNum, argNum, argNum)
			args = append(args, "%"+keyword+"%")
			argNum++
		}
	}

	if !countOnly {
		query += " ORDER BY s.last_name, s.first_name"

		if limit > 0 {
			query += fmt.Sprintf(" LIMIT $%d", argNum)
			args = append(args, limit)
			argNum++
		}

		if offset > 0 {
			query += fmt.Sprintf(" OFFSET $%d", argNum)
			args = append(args, offset)
		}
	}

	return query, args
}

// UpdateAudienceCount updates the cached member count for an audience
func (r *PostgresRepository) UpdateAudienceCount(ctx context.Context, id uuid.UUID) (int, error) {
	// Get the audience filters
	audience, err := r.GetAudience(ctx, id)
	if err != nil {
		return 0, fmt.Errorf("failed to get audience: %w", err)
	}

	// Count members
	countQuery, countArgs := r.buildAudienceMemberQuery(audience.Filters, 0, 0, true)
	var count int
	if err := r.pool.QueryRow(ctx, countQuery, countArgs...).Scan(&count); err != nil {
		return 0, fmt.Errorf("failed to count members: %w", err)
	}

	// Update the cached count
	updateQuery := `
		UPDATE audiences
		SET member_count = $2, last_count_update = NOW(), updated_at = NOW()
		WHERE id = $1
	`
	if _, err := r.pool.Exec(ctx, updateQuery, id, count); err != nil {
		return 0, fmt.Errorf("failed to update count: %w", err)
	}

	return count, nil
}

// CreateExport creates a new export record
func (r *PostgresRepository) CreateExport(ctx context.Context, export *AudienceExport) error {
	query := `
		INSERT INTO audience_exports (audience_id, export_type, record_count, file_path, exported_by, purpose)
		VALUES ($1, $2, $3, $4, $5, $6)
		RETURNING id, created_at
	`

	return r.pool.QueryRow(ctx, query,
		export.AudienceID,
		export.ExportType,
		export.RecordCount,
		export.FilePath,
		export.ExportedBy,
		export.Purpose,
	).Scan(&export.ID, &export.CreatedAt)
}

// ListExports lists exports for an audience
func (r *PostgresRepository) ListExports(ctx context.Context, audienceID uuid.UUID) ([]AudienceExport, error) {
	query := `
		SELECT id, audience_id, export_type, record_count, file_path, exported_by, purpose, created_at
		FROM audience_exports
		WHERE audience_id = $1
		ORDER BY created_at DESC
	`

	rows, err := r.pool.Query(ctx, query, audienceID)
	if err != nil {
		return nil, fmt.Errorf("failed to query exports: %w", err)
	}
	defer rows.Close()

	var exports []AudienceExport
	for rows.Next() {
		var e AudienceExport
		if err := rows.Scan(
			&e.ID, &e.AudienceID, &e.ExportType, &e.RecordCount,
			&e.FilePath, &e.ExportedBy, &e.Purpose, &e.CreatedAt,
		); err != nil {
			return nil, fmt.Errorf("failed to scan export: %w", err)
		}
		exports = append(exports, e)
	}

	return exports, rows.Err()
}