lowfat-core 0.3.2

use anyhow::Result;
use rusqlite::Connection;
use std::path::Path;

/// SQLite tracking database. Same schema as the bash version.
pub struct Db {
    conn: Connection,
}

/// A single tracked command execution.
pub struct TrackRecord {
    pub original_cmd: String,
    pub lowfat_cmd: String,
    pub raw: String,
    pub filtered: String,
    pub exec_time_ms: u64,
    pub project_path: String,
}

/// Summary row from gain report.
#[derive(Debug)]
pub struct GainSummary {
    pub commands: u64,
    pub input_tokens: u64,
    pub output_tokens: u64,
    pub saved_tokens: u64,
    pub savings_pct: f64,
}

/// Top command row from gain report.
#[derive(Debug)]
pub struct TopCommand {
    pub command: String,
    pub runs: u64,
    pub saved: i64,
    pub avg_pct: f64,
}

/// Session summary.
#[derive(Debug)]
pub struct SessionSummary {
    pub commands: u64,
    pub input_tokens: u64,
    pub output_tokens: u64,
    pub saved_tokens: i64,
    pub savings_pct: f64,
    pub total_time_ms: u64,
}

impl Db {
    /// Open (or create) the tracking database.
    pub fn open(data_dir: &Path) -> Result<Self> {
        std::fs::create_dir_all(data_dir)?;
        let db_path = data_dir.join("history.db");
        let conn = Connection::open(&db_path)?;
        conn.execute_batch(
            "CREATE TABLE IF NOT EXISTS commands (
                id INTEGER PRIMARY KEY,
                timestamp TEXT NOT NULL,
                original_cmd TEXT NOT NULL,
                lowfat_cmd TEXT NOT NULL,
                input_tokens INTEGER NOT NULL,
                output_tokens INTEGER NOT NULL,
                saved_tokens INTEGER NOT NULL,
                savings_pct REAL NOT NULL,
                exec_time_ms INTEGER DEFAULT 0,
                project_path TEXT DEFAULT ''
            );
            CREATE INDEX IF NOT EXISTS idx_timestamp ON commands(timestamp);
            CREATE INDEX IF NOT EXISTS idx_project ON commands(project_path, timestamp);

            CREATE TABLE IF NOT EXISTS audit (
                id INTEGER PRIMARY KEY,
                timestamp TEXT NOT NULL,
                plugin_name TEXT NOT NULL,
                runtime_type TEXT NOT NULL,
                command TEXT NOT NULL,
                action TEXT NOT NULL,
                checksum TEXT DEFAULT '',
                details TEXT DEFAULT ''
            );
            CREATE INDEX IF NOT EXISTS idx_audit_ts ON audit(timestamp);",
        )?;
        Ok(Db { conn })
    }

    /// Record a command execution.
    pub fn track(&self, record: &TrackRecord) -> Result<()> {
        let in_tok = crate::tokens::estimate_tokens(&record.raw);
        let out_tok = crate::tokens::estimate_tokens(&record.filtered);
        let saved = in_tok as i64 - out_tok as i64;
        let pct = if in_tok > 0 {
            (saved as f64 / in_tok as f64) * 100.0
        } else {
            0.0
        };

        self.conn.execute(
            "INSERT INTO commands(timestamp, original_cmd, lowfat_cmd, input_tokens, output_tokens, saved_tokens, savings_pct, exec_time_ms, project_path)
             VALUES(datetime('now'), ?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8)",
            rusqlite::params![
                record.original_cmd,
                record.lowfat_cmd,
                in_tok as i64,
                out_tok as i64,
                saved,
                pct,
                record.exec_time_ms as i64,
                record.project_path,
            ],
        )?;
        Ok(())
    }

    /// Lifetime gain summary.
    pub fn gain_summary(&self) -> Result<GainSummary> {
        let mut stmt = self.conn.prepare(
            "SELECT COUNT(*), COALESCE(SUM(input_tokens),0), COALESCE(SUM(output_tokens),0),
                    COALESCE(SUM(saved_tokens),0),
                    CASE WHEN SUM(input_tokens)>0
                      THEN ROUND(100.0*SUM(saved_tokens)/SUM(input_tokens),1) ELSE 0 END
             FROM commands",
        )?;
        let row = stmt.query_row([], |row| {
            Ok(GainSummary {
                commands: row.get::<_, i64>(0)? as u64,
                input_tokens: row.get::<_, i64>(1)? as u64,
                output_tokens: row.get::<_, i64>(2)? as u64,
                saved_tokens: row.get::<_, i64>(3)? as u64,
                savings_pct: row.get(4)?,
            })
        })?;
        Ok(row)
    }

    /// Top commands by tokens saved.
    pub fn top_commands(&self, limit: usize) -> Result<Vec<TopCommand>> {
        let mut stmt = self.conn.prepare(
            "SELECT original_cmd, COUNT(*), SUM(saved_tokens), ROUND(AVG(savings_pct),1)
             FROM commands GROUP BY original_cmd ORDER BY SUM(saved_tokens) DESC LIMIT ?1",
        )?;
        let rows = stmt.query_map([limit as i64], |row| {
            Ok(TopCommand {
                command: row.get(0)?,
                runs: row.get::<_, i64>(1)? as u64,
                saved: row.get(2)?,
                avg_pct: row.get(3)?,
            })
        })?;
        rows.collect::<Result<Vec<_>, _>>().map_err(Into::into)
    }

    /// Session summary since a given timestamp.
    pub fn session_summary(&self, since: &str) -> Result<SessionSummary> {
        let mut stmt = self.conn.prepare(
            "SELECT COUNT(*),
                    COALESCE(SUM(input_tokens),0),
                    COALESCE(SUM(output_tokens),0),
                    COALESCE(SUM(saved_tokens),0),
                    CASE WHEN SUM(input_tokens)>0
                      THEN ROUND(100.0*SUM(saved_tokens)/SUM(input_tokens),1) ELSE 0 END,
                    COALESCE(SUM(exec_time_ms),0)
             FROM commands WHERE timestamp >= ?1",
        )?;
        let row = stmt.query_row([since], |row| {
            Ok(SessionSummary {
                commands: row.get::<_, i64>(0)? as u64,
                input_tokens: row.get::<_, i64>(1)? as u64,
                output_tokens: row.get::<_, i64>(2)? as u64,
                saved_tokens: row.get(3)?,
                savings_pct: row.get(4)?,
                total_time_ms: row.get::<_, i64>(5)? as u64,
            })
        })?;
        Ok(row)
    }

    /// Record an audit event (plugin load, security check, etc.).
    pub fn audit(
        &self,
        plugin_name: &str,
        runtime_type: &str,
        command: &str,
        action: &str,
        checksum: &str,
        details: &str,
    ) -> Result<()> {
        self.conn.execute(
            "INSERT INTO audit(timestamp, plugin_name, runtime_type, command, action, checksum, details)
             VALUES(datetime('now'), ?1, ?2, ?3, ?4, ?5, ?6)",
            rusqlite::params![plugin_name, runtime_type, command, action, checksum, details],
        )?;
        Ok(())
    }

    /// Get recent audit entries.
    pub fn audit_log(&self, limit: usize) -> Result<Vec<AuditEntry>> {
        let mut stmt = self.conn.prepare(
            "SELECT timestamp, plugin_name, runtime_type, command, action, checksum, details
             FROM audit ORDER BY id DESC LIMIT ?1",
        )?;
        let rows = stmt.query_map([limit as i64], |row| {
            Ok(AuditEntry {
                timestamp: row.get(0)?,
                plugin_name: row.get(1)?,
                runtime_type: row.get(2)?,
                command: row.get(3)?,
                action: row.get(4)?,
                checksum: row.get(5)?,
                details: row.get(6)?,
            })
        })?;
        rows.collect::<Result<Vec<_>, _>>().map_err(Into::into)
    }
}

/// Audit log entry.
#[derive(Debug)]
pub struct AuditEntry {
    pub timestamp: String,
    pub plugin_name: String,
    pub runtime_type: String,
    pub command: String,
    pub action: String,
    pub checksum: String,
    pub details: String,
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn db_create_and_track() {
        let tmp = tempfile::tempdir().unwrap();
        let db = Db::open(tmp.path()).unwrap();

        let record = TrackRecord {
            original_cmd: "git status".to_string(),
            lowfat_cmd: "lowfat git status".to_string(),
            raw: "a".repeat(100), // 25 tokens
            filtered: "a".repeat(40), // 10 tokens
            exec_time_ms: 50,
            project_path: "/tmp/test".to_string(),
        };
        db.track(&record).unwrap();

        let summary = db.gain_summary().unwrap();
        assert_eq!(summary.commands, 1);
        assert_eq!(summary.input_tokens, 25);
        assert_eq!(summary.output_tokens, 10);
        assert_eq!(summary.saved_tokens, 15);
    }

    #[test]
    fn top_commands() {
        let tmp = tempfile::tempdir().unwrap();
        let db = Db::open(tmp.path()).unwrap();

        for _ in 0..3 {
            db.track(&TrackRecord {
                original_cmd: "git diff".to_string(),
                lowfat_cmd: "lowfat git diff".to_string(),
                raw: "a".repeat(100),
                filtered: "a".repeat(20),
                exec_time_ms: 10,
                project_path: "/tmp".to_string(),
            }).unwrap();
        }

        let top = db.top_commands(10).unwrap();
        assert_eq!(top.len(), 1);
        assert_eq!(top[0].command, "git diff");
        assert_eq!(top[0].runs, 3);
    }
}