Phase 1: data layer (SQLite, migrations, models, seed)

2026-06-25 20:25:14 -07:00
parent e72d48d64e
commit 9c98e97030
7 changed files with 403 additions and 7 deletions
--- a/internal/db/db.go
+++ b/internal/db/db.go
@@ -0,0 +1,184 @@
+// Package db owns the SQLite connection, schema migrations, and the core data
+// models. It uses modernc.org/sqlite (pure Go, no cgo) so the app stays a
+// single static binary.
+package db
+
+import (
+	"database/sql"
+	"fmt"
+	"net/url"
+	"os"
+	"path/filepath"
+
+	_ "modernc.org/sqlite"
+)
+
+// LocalUserID is the id of the single hardcoded user the app runs as while auth
+// is deferred. The seeded row keeps foreign keys valid; real auth replaces it
+// later without a schema change.
+const LocalUserID = "local"
+
+// DB wraps the SQL handle. It's a thin alias today, leaving room for prepared
+// statements or helpers later without churning call sites.
+type DB struct {
+	*sql.DB
+}
+
+// Open initialises the database at path: it ensures the parent directory
+// exists, opens the connection with foreign keys and WAL enabled, runs all
+// pending migrations, and seeds the local user.
+func Open(path string) (*DB, error) {
+	if dir := filepath.Dir(path); dir != "" && dir != "." {
+		if err := os.MkdirAll(dir, 0o755); err != nil {
+			return nil, fmt.Errorf("create data dir: %w", err)
+		}
+	}
+
+	sqlDB, err := sql.Open("sqlite", dsn(path))
+	if err != nil {
+		return nil, fmt.Errorf("open sqlite: %w", err)
+	}
+	// SQLite is a single writer; one connection avoids "database is locked"
+	// churn while keeping WAL's concurrent readers.
+	sqlDB.SetMaxOpenConns(1)
+
+	if err := sqlDB.Ping(); err != nil {
+		_ = sqlDB.Close()
+		return nil, fmt.Errorf("ping sqlite: %w", err)
+	}
+
+	d := &DB{sqlDB}
+	if err := d.migrate(); err != nil {
+		_ = sqlDB.Close()
+		return nil, fmt.Errorf("migrate: %w", err)
+	}
+	if err := d.seed(); err != nil {
+		_ = sqlDB.Close()
+		return nil, fmt.Errorf("seed: %w", err)
+	}
+	return d, nil
+}
+
+// dsn builds the modernc.org/sqlite connection string with the pragmas we want
+// applied to every connection.
+func dsn(path string) string {
+	q := url.Values{}
+	q.Add("_pragma", "foreign_keys(1)")
+	q.Add("_pragma", "busy_timeout(5000)")
+	q.Add("_pragma", "journal_mode(WAL)")
+	return "file:" + path + "?" + q.Encode()
+}
+
+// migration is one ordered, idempotent schema step. Append new migrations to the
+// slice in migrate(); never edit or reorder an already-shipped one.
+type migration struct {
+	name string
+	stmt string
+}
+
+// migrate runs every migration not yet recorded in schema_migrations, inside a
+// transaction each, in order.
+func (d *DB) migrate() error {
+	if _, err := d.Exec(`CREATE TABLE IF NOT EXISTS schema_migrations (
+		name       TEXT PRIMARY KEY,
+		applied_at DATETIME DEFAULT CURRENT_TIMESTAMP
+	)`); err != nil {
+		return err
+	}
+
+	for _, m := range migrations() {
+		var exists bool
+		if err := d.QueryRow(
+			`SELECT EXISTS(SELECT 1 FROM schema_migrations WHERE name = ?)`, m.name,
+		).Scan(&exists); err != nil {
+			return err
+		}
+		if exists {
+			continue
+		}
+
+		tx, err := d.Begin()
+		if err != nil {
+			return err
+		}
+		if _, err := tx.Exec(m.stmt); err != nil {
+			_ = tx.Rollback()
+			return fmt.Errorf("migration %q: %w", m.name, err)
+		}
+		if _, err := tx.Exec(`INSERT INTO schema_migrations (name) VALUES (?)`, m.name); err != nil {
+			_ = tx.Rollback()
+			return fmt.Errorf("record migration %q: %w", m.name, err)
+		}
+		if err := tx.Commit(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// migrations returns the ordered schema history. The initial migration mirrors
+// the schema in petal-spec.md.
+func migrations() []migration {
+	return []migration{
+		{
+			name: "0001_initial_schema",
+			stmt: `
+CREATE TABLE users (
+    id           TEXT PRIMARY KEY,
+    email        TEXT NOT NULL,
+    display_name TEXT,
+    created_at   DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE TABLE documents (
+    id           TEXT PRIMARY KEY DEFAULT (lower(hex(randomblob(16)))),
+    user_id      TEXT NOT NULL REFERENCES users(id),
+    title        TEXT NOT NULL DEFAULT 'Untitled',
+    content      TEXT NOT NULL DEFAULT '{}',
+    content_text TEXT NOT NULL DEFAULT '',
+    word_count   INTEGER NOT NULL DEFAULT 0,
+    created_at   DATETIME DEFAULT CURRENT_TIMESTAMP,
+    updated_at   DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE TABLE suggestions (
+    id           TEXT PRIMARY KEY DEFAULT (lower(hex(randomblob(16)))),
+    doc_id       TEXT NOT NULL REFERENCES documents(id) ON DELETE CASCADE,
+    from_pos     INTEGER NOT NULL,
+    to_pos       INTEGER NOT NULL,
+    original     TEXT NOT NULL,
+    replacement  TEXT NOT NULL,
+    explanation  TEXT NOT NULL,
+    type         TEXT NOT NULL CHECK(type IN ('grammar','phrasing','idiom','clarity','voice')),
+    status       TEXT NOT NULL DEFAULT 'pending' CHECK(status IN ('pending','accepted','rejected')),
+    created_at   DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE TABLE plagiarism_reports (
+    id              TEXT PRIMARY KEY DEFAULT (lower(hex(randomblob(16)))),
+    doc_id          TEXT NOT NULL REFERENCES documents(id) ON DELETE CASCADE,
+    backend         TEXT NOT NULL DEFAULT 'copyleaks',
+    similarity_pct  REAL,
+    status          TEXT NOT NULL DEFAULT 'pending'
+                    CHECK(status IN ('pending','complete','error')),
+    result_json     TEXT,
+    created_at      DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE INDEX idx_suggestions_doc_id ON suggestions(doc_id);
+CREATE INDEX idx_plagiarism_doc_id ON plagiarism_reports(doc_id);
+`,
+		},
+	}
+}
+
+// seed inserts the hardcoded local user if it doesn't already exist. It's
+// idempotent, so it runs safely on every startup.
+func (d *DB) seed() error {
+	_, err := d.Exec(
+		`INSERT INTO users (id, email, display_name) VALUES (?, ?, ?)
+		 ON CONFLICT(id) DO NOTHING`,
+		LocalUserID, "local@petal.local", "Writer",
+	)
+	return err
+}