/*
 * db.h — SQLite storage for sovereign_browser
 *
 * Provides persistent local storage for Nostr events and misc data.
 * The database lives at ~/.sovereign_browser/browser.db.
 *
 * Tables:
 *   events      — Nostr events (id, pubkey, kind, created_at, content, sig, raw_json)
 *   event_tags  — Tag rows for querying by tag name/value
 *   key_value   — Simple key-value store for misc settings/cache
 *
 * Thread safety: the database is opened with SQLITE_OPEN_FULLMUTEX, so
 * calls from multiple threads are safe (serialized by SQLite's mutex).
 */

#ifndef DB_H
#define DB_H

#include <glib.h>

/* cJSON is in the vendored nostr_core_lib */
#include "../nostr_core_lib/cjson/cJSON.h"

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Initialize the database at ~/.sovereign_browser/browser.db.
 * Creates tables and indexes if they don't exist.
 * Kept for compatibility; prefer db_init_with_path() for per-user dbs.
 *
 * Returns 0 on success, -1 on error.
 */
int  db_init(void);

/*
 * Initialize the global database at ~/.sovereign_browser/global.db.
 * Used at startup for global settings + shortcuts, before login.
 * Creates tables and indexes if they don't exist.
 *
 * Returns 0 on success, -1 on error.
 */
int  db_init_global(void);

/*
 * Open a SQLite database at the given path with the standard schema.
 * Closes any currently-open database first (so you can switch from
 * global.db to a per-user browser.db after login).
 *
 * Returns 0 on success, -1 on error.
 */
int  db_init_with_path(const char *path);

/*
 * Close the database. Call at shutdown, or before switching to a
 * different database via db_init_with_path().
 */
void db_close(void);

/* ── Events ────────────────────────────────────────────────────────── */

/*
 * Store a Nostr event (upsert — replaces if same event_id exists).
 * Parses the cJSON event and stores it in the events + event_tags tables.
 *
 *   event — a cJSON object representing a Nostr event with at least:
 *           id, pubkey, kind, created_at, content, sig, tags
 *
 * Returns 0 on success, -1 on error.
 */
int  db_store_event(const cJSON *event);

/*
 * Fetch the most recent event of a given kind for a pubkey.
 *
 * Returns a newly allocated cJSON event (parsed from raw_json), or NULL
 * if not found. Caller must cJSON_Delete() the result.
 */
cJSON *db_get_latest_event(const char *pubkey_hex, int kind);

/*
 * Fetch all events of a given kind for a pubkey, newest first.
 *
 *   limit — max number of events (0 = no limit)
 *
 * Returns a cJSON array of event objects. Caller must cJSON_Delete().
 * Returns NULL on error.
 */
cJSON *db_get_events(const char *pubkey_hex, int kind, int limit);

/*
 * Count events of a given kind for a pubkey.
 * Returns the count, or -1 on error.
 */
int  db_count_events(const char *pubkey_hex, int kind);

/*
 * Fetch all events of a given kind from ALL authors (no pubkey filter),
 * newest first. Used for public events like kind 31123 skills that are
 * authored by anyone.
 *
 *   limit — max number of events (0 = no limit)
 *
 * Returns a cJSON array of event objects. Caller must cJSON_Delete().
 * Returns NULL on error.
 */
cJSON *db_get_events_by_kind(int kind, int limit);

/*
 * Delete a single event by its event id (and its tags, via cascade).
 * Returns 0 on success, -1 on error.
 */
int  db_delete_event(const char *event_id);

/* ── Key-Value store ───────────────────────────────────────────────── */

/*
 * Set a key-value pair (upsert) in the currently-open database.
 * Returns 0 on success, -1 on error.
 */
int  db_kv_set(const char *key, const char *value);

/*
 * Set a key-value pair in a specific database file, opening a separate
 * short-lived connection. Used to save global settings to global.db
 * while the per-user browser.db is the main open database. Creates the
 * key_value table if it doesn't exist.
 * Returns 0 on success, -1 on error.
 */
int  db_kv_set_to_file(const char *path, const char *key, const char *value);

/*
 * Get a value by key.
 * Returns a pointer to the value string, or NULL if not found.
 * The pointer is valid until the next db_kv_get() call (uses a static
 * buffer). Call db_kv_get_copy() if you need a persistent copy.
 */
const char *db_kv_get(const char *key);

/*
 * Get a value by key, returning a newly allocated copy.
 * Caller must g_free() the result. Returns NULL if not found.
 */
char *db_kv_get_copy(const char *key);

/* ── History ───────────────────────────────────────────────────────── */

/*
 * Add a URL to the history (UPSERT — increments visit_count and updates
 * visited_at if the URL already exists).
 *   url   — the URL to record
 *   title — optional page title (NULL or "" for none)
 * Returns 0 on success, -1 on error.
 */
int  db_history_add(const char *url, const char *title);

/*
 * Get recent history entries (most-recent-first).
 *   limit — max number of entries (0 = default 50)
 *
 * Fills urls_out and titles_out with parallel arrays of newly allocated
 * strings. Caller must free each string and the arrays themselves.
 * Returns the number of entries, or -1 on error.
 */
int  db_history_get(char ***urls_out, char ***titles_out,
                     int *count_out, int limit);

/*
 * Clear all history entries.
 * Returns 0 on success, -1 on error.
 */
int  db_history_clear(void);

/*
 * Search history entries by URL or title substring.
 *   query     — substring to search for (case-insensitive)
 *   limit     — max number of entries (0 = default 10)
 *
 * Results are ranked by visit_count DESC, then visited_at DESC — so
 * frequently-visited and recently-visited sites appear first.
 *
 * Fills urls_out and titles_out with parallel arrays of newly allocated
 * strings. Caller must free each string and the arrays themselves.
 * Returns the number of entries, or -1 on error.
 */
int  db_history_search(const char *query,
                        char ***urls_out, char ***titles_out,
                        int *count_out, int limit);

/* ── Session ───────────────────────────────────────────────────────── */

/*
 * Save the current session (open tab URLs) to the database.
 * Clears the session table first, then inserts the given URLs in order.
 *   urls    — array of URL strings
 *   titles  — array of title strings (can be NULL for no titles)
 *   count   — number of tabs
 * Returns 0 on success, -1 on error.
 */
int  db_session_save(const char **urls, const char **titles, int count);

/*
 * Load the saved session from the database.
 * Fills urls_out and titles_out with parallel arrays (tab_index order).
 * Caller must free each string and the arrays.
 * Returns the number of tabs, or -1 on error / no session.
 */
int  db_session_load(char ***urls_out, char ***titles_out, int *count_out);

/*
 * Clear the saved session.
 * Returns 0 on success, -1 on error.
 */
int  db_session_clear(void);

/* ── Agent chat sessions ───────────────────────────────────────────── */

/*
 * Create a new chat session. Returns the session ID (newly allocated string,
 * caller must g_free). Returns NULL on error.
 */
char *db_agent_session_create(const char *title);

/*
 * Get the most recent chat session ID. Returns a newly allocated string,
 * or NULL if no sessions exist. Caller must g_free.
 */
char *db_agent_session_get_latest(void);

/*
 * Update a session's title and updated_at timestamp.
 * Returns 0 on success, -1 on error.
 */
int  db_agent_session_update(const char *session_id, const char *title);

/*
 * List all chat sessions, newest first. Fills arrays with session IDs and
 * titles. Caller must free each string and the arrays.
 * Returns the number of sessions, or -1 on error.
 */
int  db_agent_session_list(char ***ids_out, char ***titles_out,
                           int *count_out);

/*
 * Add a message to a chat session.
 *   role         — "user", "assistant", "tool", or "system"
 *   content      — message text (may be NULL for assistant msgs with only tool_calls)
 *   tool_calls   — JSON string of tool calls array (may be NULL)
 *   tool_call_id — for role="tool", the ID of the tool call this responds to (may be NULL)
 * Returns the message row ID (>0) on success, -1 on error.
 */
int  db_agent_message_add(const char *session_id, const char *role,
                          const char *content, const char *tool_calls,
                          const char *tool_call_id);

/*
 * Load all messages for a session, ordered by created_at (oldest first).
 * Returns a cJSON array of message objects, each with:
 *   {"id":N, "role":"...", "content":"...", "tool_calls":"...", "tool_call_id":"..."}
 * Returns NULL on error. Caller must cJSON_Delete().
 */
cJSON *db_agent_message_list(const char *session_id);

/*
 * Delete a chat session and all its messages.
 * Returns 0 on success, -1 on error.
 */
int  db_agent_session_delete(const char *session_id);

#ifdef __cplusplus
}
#endif

#endif /* DB_H */