use crate::notebook::testing::types::{Cell, CoverageReport};

/// Coverage tracking for notebook tests
pub struct CoverageTracker {
    lines_covered: usize,
    total_lines: usize,
}

/// Instrumented cell with coverage probes
pub struct InstrumentedCell {
    cell: Cell,
    probes: Vec<usize>,
}

impl Default for CoverageTracker {
    fn default() -> Self {
        Self::new()
    }
}

impl CoverageTracker {
    /// # Examples
    ///
    /// ```
    /// use ruchy::notebook::testing::coverage::CoverageTracker;
    ///
    /// let instance = CoverageTracker::new();
    /// // Verify behavior
    /// ```
    pub fn new() -> Self {
        Self {
            lines_covered: 0,
            total_lines: 0,
        }
    }
    /// # Examples
    ///
    /// ```
    /// use ruchy::notebook::testing::coverage::CoverageTracker;
    ///
    /// let mut instance = CoverageTracker::new();
    /// let result = instance.instrument_cell();
    /// // Verify behavior
    /// ```
    pub fn instrument_cell(&self, cell: &Cell) -> InstrumentedCell {
        InstrumentedCell {
            cell: cell.clone(),
            probes: vec![1, 2, 3], // Stub probe positions
        }
    }
    /// # Examples
    ///
    /// ```
    /// use ruchy::notebook::testing::coverage::CoverageTracker;
    ///
    /// let mut instance = CoverageTracker::new();
    /// let result = instance.execute_instrumented();
    /// // Verify behavior
    /// ```
    pub fn execute_instrumented(&self, _instrumented: &InstrumentedCell, _code: &str) {
        // Stub implementation for Sprint 0
    }
    /// # Examples
    ///
    /// ```ignore
    /// use ruchy::notebook::testing::coverage::report_coverage;
    ///
    /// let result = report_coverage(());
    /// assert_eq!(result, Ok(()));
    /// ```
    pub fn report_coverage(&self) -> CoverageReport {
        CoverageReport {
            line_coverage: 0.5,   // Stub value
            branch_coverage: 0.3, // Stub value
            uncovered_sections: Vec::new(),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::notebook::testing::types::{CellMetadata, CellType};

    fn create_test_cell() -> Cell {
        Cell {
            id: "test_cell".to_string(),
            source: "println('test')".to_string(),
            cell_type: CellType::Code,
            metadata: CellMetadata::default(),
        }
    }

    #[test]
    fn test_coverage_tracker_new() {
        let tracker = CoverageTracker::new();
        assert_eq!(tracker.lines_covered, 0);
        assert_eq!(tracker.total_lines, 0);
    }

    #[test]
    fn test_coverage_tracker_default() {
        let tracker = CoverageTracker::default();
        assert_eq!(tracker.lines_covered, 0);
        assert_eq!(tracker.total_lines, 0);
    }

    #[test]
    fn test_instrument_cell() {
        let tracker = CoverageTracker::new();
        let cell = create_test_cell();
        let instrumented = tracker.instrument_cell(&cell);

        assert_eq!(instrumented.cell.id, "test_cell");
        assert_eq!(instrumented.cell.source, "println('test')");
        assert_eq!(instrumented.probes, vec![1, 2, 3]);
    }

    #[test]
    fn test_execute_instrumented() {
        let tracker = CoverageTracker::new();
        let cell = create_test_cell();
        let instrumented = tracker.instrument_cell(&cell);

        // Should not panic
        tracker.execute_instrumented(&instrumented, "test code");
    }

    #[test]
    fn test_report_coverage() {
        let tracker = CoverageTracker::new();
        let report = tracker.report_coverage();

        assert_eq!(report.line_coverage, 0.5);
        assert_eq!(report.branch_coverage, 0.3);
        assert!(report.uncovered_sections.is_empty());
    }

    #[test]
    fn test_instrumented_cell_creation() {
        let cell = create_test_cell();
        let instrumented = InstrumentedCell {
            cell: cell.clone(),
            probes: vec![1, 5, 10],
        };

        assert_eq!(instrumented.cell.id, cell.id);
        assert_eq!(instrumented.cell.source, cell.source);
        assert_eq!(instrumented.probes, vec![1, 5, 10]);
    }

    #[test]
    fn test_multiple_instrumented_cells() {
        let tracker = CoverageTracker::new();
        let cell1 = Cell {
            id: "cell1".to_string(),
            source: "x = 1".to_string(),
            cell_type: CellType::Code,
            metadata: CellMetadata::default(),
        };
        let cell2 = Cell {
            id: "cell2".to_string(),
            source: "y = 2".to_string(),
            cell_type: CellType::Code,
            metadata: CellMetadata::default(),
        };

        let instrumented1 = tracker.instrument_cell(&cell1);
        let instrumented2 = tracker.instrument_cell(&cell2);

        assert_eq!(instrumented1.cell.id, "cell1");
        assert_eq!(instrumented2.cell.id, "cell2");
        assert_eq!(instrumented1.probes, vec![1, 2, 3]);
        assert_eq!(instrumented2.probes, vec![1, 2, 3]);
    }

    #[test]
    fn test_coverage_with_empty_code() {
        let tracker = CoverageTracker::new();
        let cell = Cell {
            id: "empty_cell".to_string(),
            source: String::new(),
            cell_type: CellType::Code,
            metadata: CellMetadata::default(),
        };

        let instrumented = tracker.instrument_cell(&cell);
        tracker.execute_instrumented(&instrumented, "");

        let report = tracker.report_coverage();
        assert!(report.line_coverage >= 0.0);
        assert!(report.branch_coverage >= 0.0);
    }

    #[test]
    fn test_coverage_tracker_state_unchanged() {
        let tracker = CoverageTracker::new();
        let initial_covered = tracker.lines_covered;
        let initial_total = tracker.total_lines;

        let cell = create_test_cell();
        let instrumented = tracker.instrument_cell(&cell);
        tracker.execute_instrumented(&instrumented, "test");
        let _report = tracker.report_coverage();

        // State should remain unchanged (immutable operations)
        assert_eq!(tracker.lines_covered, initial_covered);
        assert_eq!(tracker.total_lines, initial_total);
    }
}
