use crate::store::STORE_TABLE;
use redb::{Database, ReadableTable};
use std::path::Path;
use std::sync::Arc;

pub fn init_redb(base: &Path) -> Arc<Database> {
    let redb_path = base.join("mcp_store.redb");
    let db = Arc::new(redb::Database::create(&redb_path).expect("Failed to create redb database"));

    // Ensure the table exists and migrate legacy JSON files
    let write_txn = db.begin_write().expect("Failed to begin write txn on redb");
    {
        let mut table = write_txn
            .open_table(STORE_TABLE)
            .expect("Failed to open STORE_TABLE");

        let stores = vec![
            ("knowledge_graph_master", "knowledge_graph_master.json"),
            ("audit_ledger", "audit_ledger.json"),
            ("sticky_notes", "sticky_notes.json"),
            ("tasks", "tasks.json"),
            ("snippets", "snippets.json"),
            ("adrs", "adrs.json"),
            ("preferences", "preferences.json"),
            ("error_fixes", "error_fixes.json"),
            ("pinned_files", "pinned_files.json"),
            ("session_summaries", "session_summaries.json"),
            ("handoff_memos", "handoff_memos.json"),
            ("env_fingerprints", "env_fingerprints.json"),
            ("env_requirements", "env_requirements.json"),
            ("milestones", "milestones.json"),
            ("environments", "environments.json"),
            ("pr_checklists", "pr_checklists.json"),
            ("tech_debts", "tech_debts.json"),
            ("gates", "gates.json"),
            ("context_workspaces", "context_workspaces.json"),
        ];

        for (key, file_name) in stores.iter() {
            if table
                .get(*key)
                .expect("Failed to read from table")
                .is_none()
            {
                let json_path = base.join(file_name);
                if json_path.exists()
                    && let Ok(data) = std::fs::read(&json_path)
                    && serde_json::from_slice::<serde_json::Value>(&data).is_ok()
                {
                    table
                        .insert(*key, data.as_slice())
                        .expect("Failed to insert migrated data");
                    let _ = std::fs::rename(&json_path, json_path.with_extension("json.migrated"));
                }
            }
        }
    }
    write_txn.commit().expect("Failed to commit db migration");

    db
}