package postgres

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

	"git.gobha.me/xcaliber/chat-switchboard/models"
)

type WorkspaceStore struct{}

func NewWorkspaceStore() *WorkspaceStore { return &WorkspaceStore{} }

// ── columns ────────────────────────────────

const workspaceCols = `id, owner_type, owner_id, name, root_path, max_bytes, status, indexing_enabled, created_at, updated_at`
const workspaceFileCols = `id, workspace_id, path, is_directory, content_type, size_bytes, sha256, index_status, chunk_count, created_at, updated_at`

// ── scanners ───────────────────────────────

func scanWorkspace(row interface{ Scan(dest ...interface{}) error }) (*models.Workspace, error) {
	var w models.Workspace
	var maxBytes sql.NullInt64
	err := row.Scan(
		&w.ID, &w.OwnerType, &w.OwnerID, &w.Name,
		&w.RootPath, &maxBytes, &w.Status, &w.IndexingEnabled,
		&w.CreatedAt, &w.UpdatedAt,
	)
	if err != nil {
		return nil, err
	}
	if maxBytes.Valid {
		w.MaxBytes = &maxBytes.Int64
	}
	return &w, nil
}

func scanWorkspaceFile(row interface{ Scan(dest ...interface{}) error }) (*models.WorkspaceFile, error) {
	var f models.WorkspaceFile
	var contentType sql.NullString
	var sha256 sql.NullString
	var indexStatus sql.NullString
	err := row.Scan(
		&f.ID, &f.WorkspaceID, &f.Path, &f.IsDirectory,
		&contentType, &f.SizeBytes, &sha256,
		&indexStatus, &f.ChunkCount,
		&f.CreatedAt, &f.UpdatedAt,
	)
	if err != nil {
		return nil, err
	}
	if contentType.Valid {
		f.ContentType = contentType.String
	}
	if sha256.Valid {
		f.SHA256 = sha256.String
	}
	if indexStatus.Valid {
		f.IndexStatus = indexStatus.String
	}
	return &f, nil
}

// ── Workspace CRUD ─────────────────────────

func (s *WorkspaceStore) Create(ctx context.Context, w *models.Workspace) error {
	// Accept pre-generated ID or let Postgres generate one
	if w.ID != "" {
		return DB.QueryRowContext(ctx, `
			INSERT INTO workspaces (id, owner_type, owner_id, name, root_path, max_bytes, status)
			VALUES ($1, $2, $3, $4, $5, $6, $7)
			RETURNING created_at, updated_at`,
			w.ID, w.OwnerType, w.OwnerID, w.Name, w.RootPath,
			w.MaxBytes, w.Status,
		).Scan(&w.CreatedAt, &w.UpdatedAt)
	}
	return DB.QueryRowContext(ctx, `
		INSERT INTO workspaces (owner_type, owner_id, name, root_path, max_bytes, status)
		VALUES ($1, $2, $3, $4, $5, $6)
		RETURNING id, created_at, updated_at`,
		w.OwnerType, w.OwnerID, w.Name, w.RootPath,
		w.MaxBytes, w.Status,
	).Scan(&w.ID, &w.CreatedAt, &w.UpdatedAt)
}

func (s *WorkspaceStore) GetByID(ctx context.Context, id string) (*models.Workspace, error) {
	row := DB.QueryRowContext(ctx,
		`SELECT `+workspaceCols+` FROM workspaces WHERE id = $1`, id)
	return scanWorkspace(row)
}

func (s *WorkspaceStore) Update(ctx context.Context, id string, patch models.WorkspacePatch) error {
	b := NewUpdate("workspaces")
	if patch.Name != nil {
		b.Set("name", *patch.Name)
	}
	if patch.MaxBytes != nil {
		b.Set("max_bytes", *patch.MaxBytes)
	}
	if patch.Status != nil {
		b.Set("status", *patch.Status)
	}
	if patch.IndexingEnabled != nil {
		b.Set("indexing_enabled", *patch.IndexingEnabled)
	}
	if !b.HasSets() {
		return nil
	}
	b.Set("updated_at", time.Now().UTC())
	b.Where("id", id)
	_, err := b.Exec(DB)
	return err
}

func (s *WorkspaceStore) Delete(ctx context.Context, id string) error {
	_, err := DB.ExecContext(ctx, `DELETE FROM workspaces WHERE id = $1`, id)
	return err
}

// ── Ownership lookup ───────────────────────

func (s *WorkspaceStore) GetByOwner(ctx context.Context, ownerType, ownerID string) (*models.Workspace, error) {
	row := DB.QueryRowContext(ctx,
		`SELECT `+workspaceCols+` FROM workspaces
		 WHERE owner_type = $1 AND owner_id = $2 AND status != 'deleting'
		 ORDER BY created_at DESC LIMIT 1`,
		ownerType, ownerID)
	return scanWorkspace(row)
}

func (s *WorkspaceStore) ListByOwner(ctx context.Context, ownerType, ownerID string) ([]models.Workspace, error) {
	rows, err := DB.QueryContext(ctx,
		`SELECT `+workspaceCols+` FROM workspaces
		 WHERE owner_type = $1 AND owner_id = $2 AND status != 'deleting'
		 ORDER BY created_at DESC`,
		ownerType, ownerID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var out []models.Workspace
	for rows.Next() {
		w, err := scanWorkspace(rows)
		if err != nil {
			return nil, err
		}
		out = append(out, *w)
	}
	return out, rows.Err()
}

// ── File index ─────────────────────────────

func (s *WorkspaceStore) UpsertFile(ctx context.Context, f *models.WorkspaceFile) error {
	return DB.QueryRowContext(ctx, `
		INSERT INTO workspace_files (workspace_id, path, is_directory, content_type, size_bytes, sha256)
		VALUES ($1, $2, $3, $4, $5, $6)
		ON CONFLICT (workspace_id, path) DO UPDATE SET
			is_directory = EXCLUDED.is_directory,
			content_type = EXCLUDED.content_type,
			size_bytes   = EXCLUDED.size_bytes,
			sha256       = EXCLUDED.sha256,
			updated_at   = NOW()
		RETURNING id, created_at, updated_at`,
		f.WorkspaceID, f.Path, f.IsDirectory,
		models.NullString(&f.ContentType), f.SizeBytes,
		models.NullString(&f.SHA256),
	).Scan(&f.ID, &f.CreatedAt, &f.UpdatedAt)
}

func (s *WorkspaceStore) DeleteFile(ctx context.Context, workspaceID, path string) error {
	_, err := DB.ExecContext(ctx,
		`DELETE FROM workspace_files WHERE workspace_id = $1 AND path = $2`,
		workspaceID, path)
	return err
}

func (s *WorkspaceStore) DeleteFilesByPrefix(ctx context.Context, workspaceID, prefix string) error {
	_, err := DB.ExecContext(ctx,
		`DELETE FROM workspace_files WHERE workspace_id = $1 AND path LIKE $2`,
		workspaceID, prefix+"%")
	return err
}

func (s *WorkspaceStore) GetFile(ctx context.Context, workspaceID, path string) (*models.WorkspaceFile, error) {
	row := DB.QueryRowContext(ctx,
		`SELECT `+workspaceFileCols+` FROM workspace_files
		 WHERE workspace_id = $1 AND path = $2`,
		workspaceID, path)
	return scanWorkspaceFile(row)
}

func (s *WorkspaceStore) ListFiles(ctx context.Context, workspaceID, prefix string, recursive bool) ([]models.WorkspaceFile, error) {
	var query string
	var args []interface{}

	if recursive {
		// All files under prefix (recursive)
		if prefix == "" {
			query = `SELECT ` + workspaceFileCols + ` FROM workspace_files
				WHERE workspace_id = $1 ORDER BY path`
			args = []interface{}{workspaceID}
		} else {
			query = `SELECT ` + workspaceFileCols + ` FROM workspace_files
				WHERE workspace_id = $1 AND path LIKE $2 ORDER BY path`
			args = []interface{}{workspaceID, prefix + "%"}
		}
	} else {
		// Direct children only: match prefix but no additional slashes
		if prefix == "" {
			// Root level: no slash in path
			query = `SELECT ` + workspaceFileCols + ` FROM workspace_files
				WHERE workspace_id = $1 AND path NOT LIKE '%/%' ORDER BY path`
			args = []interface{}{workspaceID}
		} else {
			// Children of prefix: starts with prefix, no additional slash after prefix
			query = fmt.Sprintf(`SELECT `+workspaceFileCols+` FROM workspace_files
				WHERE workspace_id = $1 AND path LIKE $2
				AND substring(path FROM %d) NOT LIKE '%%/%%'
				ORDER BY path`, len(prefix)+1)
			args = []interface{}{workspaceID, prefix + "%"}
		}
	}

	rows, err := DB.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var out []models.WorkspaceFile
	for rows.Next() {
		f, err := scanWorkspaceFile(rows)
		if err != nil {
			return nil, err
		}
		out = append(out, *f)
	}
	return out, rows.Err()
}

func (s *WorkspaceStore) DeleteAllFiles(ctx context.Context, workspaceID string) error {
	_, err := DB.ExecContext(ctx,
		`DELETE FROM workspace_files WHERE workspace_id = $1`, workspaceID)
	return err
}

// ── Stats ──────────────────────────────────

func (s *WorkspaceStore) GetStats(ctx context.Context, workspaceID string) (*models.WorkspaceStats, error) {
	stats := &models.WorkspaceStats{WorkspaceID: workspaceID}
	err := DB.QueryRowContext(ctx, `
		SELECT
			COALESCE(SUM(CASE WHEN NOT is_directory THEN 1 ELSE 0 END), 0),
			COALESCE(SUM(CASE WHEN is_directory THEN 1 ELSE 0 END), 0),
			COALESCE(SUM(size_bytes), 0)
		FROM workspace_files WHERE workspace_id = $1`,
		workspaceID,
	).Scan(&stats.FileCount, &stats.DirCount, &stats.TotalBytes)
	if err != nil {
		return nil, err
	}

	// Fetch quota
	var maxBytes sql.NullInt64
	err = DB.QueryRowContext(ctx,
		`SELECT max_bytes FROM workspaces WHERE id = $1`, workspaceID,
	).Scan(&maxBytes)
	if err != nil && err != sql.ErrNoRows {
		return nil, err
	}
	if maxBytes.Valid {
		stats.MaxBytes = &maxBytes.Int64
	}

	return stats, nil
}

// ── Chunks (v0.21.2) ─────────────────────────

func (s *WorkspaceStore) InsertChunks(ctx context.Context, chunks []models.WorkspaceChunk) error {
	if len(chunks) == 0 {
		return nil
	}

	const cols = 8 // workspace_id, file_id, chunk_index, content, token_count, embedding, metadata, created_at
	valueParts := make([]string, 0, len(chunks))
	args := make([]interface{}, 0, len(chunks)*cols)

	for i, c := range chunks {
		base := i * cols
		valueParts = append(valueParts, fmt.Sprintf(
			"($%d, $%d, $%d, $%d, $%d, $%d::vector, $%d, NOW())",
			base+1, base+2, base+3, base+4, base+5, base+6, base+7,
		))
		args = append(args, c.WorkspaceID, c.FileID, c.ChunkIndex,
			c.Content, c.TokenCount, vectorToString(c.Embedding), ToJSON(c.Metadata))
	}

	q := fmt.Sprintf(`INSERT INTO workspace_chunks
		(workspace_id, file_id, chunk_index, content, token_count, embedding, metadata, created_at)
		VALUES %s`, strings.Join(valueParts, ", "))

	_, err := DB.ExecContext(ctx, q, args...)
	return err
}

func (s *WorkspaceStore) DeleteChunksByFile(ctx context.Context, fileID string) error {
	_, err := DB.ExecContext(ctx, `DELETE FROM workspace_chunks WHERE file_id = $1`, fileID)
	return err
}

func (s *WorkspaceStore) SimilaritySearch(ctx context.Context, workspaceID string, queryVec []float64, threshold float64, limit int) ([]models.WorkspaceChunkResult, error) {
	if len(queryVec) == 0 {
		return nil, nil
	}
	if limit <= 0 {
		limit = 10
	}

	rows, err := DB.QueryContext(ctx, `
		SELECT f.path, c.content,
			1 - (c.embedding <=> $1::vector) AS similarity,
			c.metadata
		FROM workspace_chunks c
		JOIN workspace_files f ON c.file_id = f.id
		WHERE c.workspace_id = $2
		  AND 1 - (c.embedding <=> $1::vector) > $3
		ORDER BY c.embedding <=> $1::vector
		LIMIT $4`,
		vectorToString(queryVec), workspaceID, threshold, limit,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var results []models.WorkspaceChunkResult
	for rows.Next() {
		var r models.WorkspaceChunkResult
		var metadataJSON []byte
		if err := rows.Scan(&r.FilePath, &r.Content, &r.Score, &metadataJSON); err != nil {
			return nil, err
		}
		ScanJSON(metadataJSON, &r.Metadata)
		if r.Metadata != nil {
			if lh, ok := r.Metadata["line_start"]; ok {
				if n, ok := lh.(float64); ok {
					r.LineHint = int(n)
				}
			}
		}
		results = append(results, r)
	}
	return results, rows.Err()
}

func (s *WorkspaceStore) UpdateFileIndexStatus(ctx context.Context, fileID, status string, chunkCount int) error {
	_, err := DB.ExecContext(ctx,
		`UPDATE workspace_files SET index_status = $1, chunk_count = $2, updated_at = NOW() WHERE id = $3`,
		status, chunkCount, fileID)
	return err
}