package db

import (
	"database/sql"
	"fmt"
)

var migrations = []struct {
	name string
	sql  string
}{
	{
		name: "001_initial_schema",
		sql: `
CREATE TABLE IF NOT EXISTS users (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    username      TEXT NOT NULL UNIQUE,
    password_hash TEXT NOT NULL,
    created_at    INTEGER NOT NULL,
    updated_at    INTEGER NOT NULL
);

CREATE TABLE IF NOT EXISTS webauthn_credentials (
    id              INTEGER PRIMARY KEY AUTOINCREMENT,
    user_id         INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    credential_id   BLOB NOT NULL UNIQUE,
    public_key      BLOB NOT NULL,
    name            TEXT NOT NULL,
    sign_count      INTEGER NOT NULL DEFAULT 0,
    created_at      INTEGER NOT NULL
);

CREATE TABLE IF NOT EXISTS notebooks (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    user_id       INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    remote_id     INTEGER NOT NULL,
    title         TEXT NOT NULL,
    page_size     TEXT NOT NULL,
    synced_at     INTEGER NOT NULL,
    UNIQUE(user_id, remote_id)
);

CREATE TABLE IF NOT EXISTS pages (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    notebook_id   INTEGER NOT NULL REFERENCES notebooks(id) ON DELETE CASCADE,
    remote_id     INTEGER NOT NULL,
    page_number   INTEGER NOT NULL,
    UNIQUE(notebook_id, remote_id)
);

CREATE TABLE IF NOT EXISTS strokes (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    page_id       INTEGER NOT NULL REFERENCES pages(id) ON DELETE CASCADE,
    pen_size      REAL NOT NULL,
    color         INTEGER NOT NULL,
    style         TEXT NOT NULL DEFAULT 'plain',
    point_data    BLOB NOT NULL,
    stroke_order  INTEGER NOT NULL
);

CREATE TABLE IF NOT EXISTS share_links (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    notebook_id   INTEGER NOT NULL REFERENCES notebooks(id) ON DELETE CASCADE,
    token         TEXT NOT NULL UNIQUE,
    expires_at    INTEGER,
    created_at    INTEGER NOT NULL
);

CREATE TABLE IF NOT EXISTS schema_migrations (
    name       TEXT PRIMARY KEY,
    applied_at INTEGER NOT NULL
);

CREATE INDEX IF NOT EXISTS idx_notebooks_user ON notebooks(user_id);
CREATE INDEX IF NOT EXISTS idx_pages_notebook ON pages(notebook_id);
CREATE INDEX IF NOT EXISTS idx_strokes_page ON strokes(page_id);
CREATE INDEX IF NOT EXISTS idx_share_links_token ON share_links(token);
CREATE INDEX IF NOT EXISTS idx_webauthn_user ON webauthn_credentials(user_id);
`,
	},
}

func Migrate(database *sql.DB) error {
	// Ensure schema_migrations table exists
	_, err := database.Exec(`CREATE TABLE IF NOT EXISTS schema_migrations (
		name TEXT PRIMARY KEY, applied_at INTEGER NOT NULL)`)
	if err != nil {
		return fmt.Errorf("create schema_migrations: %w", err)
	}

	for _, m := range migrations {
		var count int
		err := database.QueryRow("SELECT COUNT(*) FROM schema_migrations WHERE name = ?", m.name).Scan(&count)
		if err != nil {
			return fmt.Errorf("check migration %s: %w", m.name, err)
		}
		if count > 0 {
			continue
		}

		if _, err := database.Exec(m.sql); err != nil {
			return fmt.Errorf("apply migration %s: %w", m.name, err)
		}

		if _, err := database.Exec(
			"INSERT INTO schema_migrations (name, applied_at) VALUES (?, strftime('%s','now'))",
			m.name,
		); err != nil {
			return fmt.Errorf("record migration %s: %w", m.name, err)
		}
	}

	return nil
}