sqlrite-engine 0.1.8

use crate::error::{Result, SQLRiteError};
use crate::sql::db::secondary_index::{IndexOrigin, SecondaryIndex};
use crate::sql::parser::create::CreateQuery;
use std::collections::{BTreeMap, HashMap};
use std::fmt;
use std::sync::{Arc, Mutex};

use prettytable::{Cell as PrintCell, Row as PrintRow, Table as PrintTable};

/// SQLRite data types
/// Mapped after SQLite Data Type Storage Classes and SQLite Affinity Type
/// (Datatypes In SQLite Version 3)[https://www.sqlite.org/datatype3.html]
#[derive(PartialEq, Debug, Clone)]
pub enum DataType {
    Integer,
    Text,
    Real,
    Bool,
    None,
    Invalid,
}

impl DataType {
    pub fn new(cmd: String) -> DataType {
        match cmd.to_lowercase().as_ref() {
            "integer" => DataType::Integer,
            "text" => DataType::Text,
            "real" => DataType::Real,
            "bool" => DataType::Bool,
            "none" => DataType::None,
            _ => {
                eprintln!("Invalid data type given {}", cmd);
                DataType::Invalid
            }
        }
    }
}

impl fmt::Display for DataType {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            DataType::Integer => f.write_str("Integer"),
            DataType::Text => f.write_str("Text"),
            DataType::Real => f.write_str("Real"),
            DataType::Bool => f.write_str("Boolean"),
            DataType::None => f.write_str("None"),
            DataType::Invalid => f.write_str("Invalid"),
        }
    }
}

/// The schema for each SQL Table is represented in memory by
/// following structure.
///
/// `rows` is `Arc<Mutex<...>>` rather than `Rc<RefCell<...>>` so `Table`
/// (and by extension `Database`) is `Send + Sync` — the Tauri desktop
/// app holds the engine in shared state behind a `Mutex<Database>`, and
/// Tauri's state container requires its contents to be thread-safe.
#[derive(Debug)]
pub struct Table {
    /// Name of the table
    pub tb_name: String,
    /// Schema for each column, in declaration order.
    pub columns: Vec<Column>,
    /// Per-column row storage, keyed by column name. Every column's
    /// `Row::T(BTreeMap)` is keyed by rowid, so all columns share the same
    /// keyset after each write.
    pub rows: Arc<Mutex<HashMap<String, Row>>>,
    /// Secondary indexes on this table (Phase 3e). One auto-created entry
    /// per UNIQUE or PRIMARY KEY column; explicit `CREATE INDEX` statements
    /// add more. Looking up an index: iterate by column name, or by index
    /// name via `Table::index_by_name`.
    pub secondary_indexes: Vec<SecondaryIndex>,
    /// ROWID of most recent insert.
    pub last_rowid: i64,
    /// PRIMARY KEY column name, or "-1" if the table has no PRIMARY KEY.
    pub primary_key: String,
}

impl Table {
    pub fn new(create_query: CreateQuery) -> Self {
        let table_name = create_query.table_name;
        let mut primary_key: String = String::from("-1");
        let columns = create_query.columns;

        let mut table_cols: Vec<Column> = vec![];
        let table_rows: Arc<Mutex<HashMap<String, Row>>> = Arc::new(Mutex::new(HashMap::new()));
        let mut secondary_indexes: Vec<SecondaryIndex> = Vec::new();
        for col in &columns {
            let col_name = &col.name;
            if col.is_pk {
                primary_key = col_name.to_string();
            }
            table_cols.push(Column::new(
                col_name.to_string(),
                col.datatype.to_string(),
                col.is_pk,
                col.not_null,
                col.is_unique,
            ));

            let dt = DataType::new(col.datatype.to_string());
            let row_storage = match dt {
                DataType::Integer => Row::Integer(BTreeMap::new()),
                DataType::Real => Row::Real(BTreeMap::new()),
                DataType::Text => Row::Text(BTreeMap::new()),
                DataType::Bool => Row::Bool(BTreeMap::new()),
                DataType::Invalid | DataType::None => Row::None,
            };
            table_rows
                .lock()
                .expect("Table row storage mutex poisoned")
                .insert(col.name.to_string(), row_storage);

            // Auto-create an index for every UNIQUE / PRIMARY KEY column,
            // but only for types we know how to index. Real / Bool UNIQUE
            // columns fall back to the linear scan path in
            // validate_unique_constraint — same behavior as before 3e.
            if (col.is_pk || col.is_unique) && matches!(dt, DataType::Integer | DataType::Text) {
                let name = SecondaryIndex::auto_name(&table_name, &col.name);
                match SecondaryIndex::new(
                    name,
                    table_name.clone(),
                    col.name.clone(),
                    &dt,
                    true,
                    IndexOrigin::Auto,
                ) {
                    Ok(idx) => secondary_indexes.push(idx),
                    Err(_) => {
                        // Unreachable given the matches! guard above, but
                        // the builder returns Result so we keep the arm.
                    }
                }
            }
        }

        Table {
            tb_name: table_name,
            columns: table_cols,
            rows: table_rows,
            secondary_indexes,
            last_rowid: 0,
            primary_key,
        }
    }

    /// Deep-clones a `Table` for transaction snapshots (Phase 4f).
    ///
    /// The normal `Clone` derive would shallow-clone the `Arc<Mutex<_>>`
    /// wrapping our row storage, leaving both copies sharing the same
    /// inner map — mutating the snapshot would corrupt the live table
    /// and vice versa. Instead we lock, clone the inner `HashMap`, and
    /// wrap it in a fresh `Arc<Mutex<_>>`. Columns and indexes derive
    /// `Clone` directly (all their fields are plain data).
    pub fn deep_clone(&self) -> Self {
        let cloned_rows: HashMap<String, Row> = {
            let guard = self.rows.lock().expect("row mutex poisoned");
            guard.clone()
        };
        Table {
            tb_name: self.tb_name.clone(),
            columns: self.columns.clone(),
            rows: Arc::new(Mutex::new(cloned_rows)),
            secondary_indexes: self.secondary_indexes.clone(),
            last_rowid: self.last_rowid,
            primary_key: self.primary_key.clone(),
        }
    }

    /// Finds an auto- or explicit-index entry for a given column. Returns
    /// `None` if the column isn't indexed.
    pub fn index_for_column(&self, column: &str) -> Option<&SecondaryIndex> {
        self.secondary_indexes
            .iter()
            .find(|i| i.column_name == column)
    }

    fn index_for_column_mut(&mut self, column: &str) -> Option<&mut SecondaryIndex> {
        self.secondary_indexes
            .iter_mut()
            .find(|i| i.column_name == column)
    }

    /// Finds a secondary index by its own name (e.g., `sqlrite_autoindex_users_email`
    /// or a user-provided CREATE INDEX name). Used by Phase 3e.2 to look up
    /// explicit indexes when DROP INDEX lands.
    #[allow(dead_code)]
    pub fn index_by_name(&self, name: &str) -> Option<&SecondaryIndex> {
        self.secondary_indexes.iter().find(|i| i.name == name)
    }

    /// Returns a `bool` informing if a `Column` with a specific name exists or not
    ///
    pub fn contains_column(&self, column: String) -> bool {
        self.columns.iter().any(|col| col.column_name == column)
    }

    /// Returns the list of column names in declaration order.
    pub fn column_names(&self) -> Vec<String> {
        self.columns.iter().map(|c| c.column_name.clone()).collect()
    }

    /// Returns all rowids currently stored in the table, in ascending order.
    /// Every column's BTreeMap has the same keyset, so we just read from the first column.
    pub fn rowids(&self) -> Vec<i64> {
        let Some(first) = self.columns.first() else {
            return vec![];
        };
        let rows = self.rows.lock().expect("rows mutex poisoned");
        rows.get(&first.column_name)
            .map(|r| r.rowids())
            .unwrap_or_default()
    }

    /// Reads a single cell at `(column, rowid)`.
    pub fn get_value(&self, column: &str, rowid: i64) -> Option<Value> {
        let rows = self.rows.lock().expect("rows mutex poisoned");
        rows.get(column).and_then(|r| r.get(rowid))
    }

    /// Removes the row identified by `rowid` from every column's storage and
    /// from every secondary index entry.
    pub fn delete_row(&mut self, rowid: i64) {
        // Snapshot the values we're about to delete so we can strip them
        // from secondary indexes by (value, rowid) before the row storage
        // disappears.
        let per_column_values: Vec<(String, Option<Value>)> = self
            .columns
            .iter()
            .map(|c| (c.column_name.clone(), self.get_value(&c.column_name, rowid)))
            .collect();

        // Remove from row storage.
        {
            let rows_clone = Arc::clone(&self.rows);
            let mut row_data = rows_clone.lock().expect("rows mutex poisoned");
            for col in &self.columns {
                if let Some(r) = row_data.get_mut(&col.column_name) {
                    match r {
                        Row::Integer(m) => {
                            m.remove(&rowid);
                        }
                        Row::Text(m) => {
                            m.remove(&rowid);
                        }
                        Row::Real(m) => {
                            m.remove(&rowid);
                        }
                        Row::Bool(m) => {
                            m.remove(&rowid);
                        }
                        Row::None => {}
                    }
                }
            }
        }

        // Strip secondary-index entries. Non-indexed columns just don't
        // show up in secondary_indexes and are no-ops here.
        for (col_name, value) in per_column_values {
            if let Some(idx) = self.index_for_column_mut(&col_name) {
                if let Some(v) = value {
                    idx.remove(&v, rowid);
                }
            }
        }
    }

    /// Replays a single row at `rowid` when loading a table from disk. Takes
    /// one typed value per column (in declaration order); `None` means the
    /// stored cell carried a NULL for that column. Unlike `insert_row` this
    /// trusts the on-disk state and does *not* re-check UNIQUE — we're
    /// rebuilding a state that was already consistent when it was saved.
    pub fn restore_row(&mut self, rowid: i64, values: Vec<Option<Value>>) -> Result<()> {
        if values.len() != self.columns.len() {
            return Err(SQLRiteError::Internal(format!(
                "cell has {} values but table '{}' has {} columns",
                values.len(),
                self.tb_name,
                self.columns.len()
            )));
        }

        let column_names: Vec<String> =
            self.columns.iter().map(|c| c.column_name.clone()).collect();

        for (i, value) in values.into_iter().enumerate() {
            let col_name = &column_names[i];

            // Write into the per-column row storage first (scoped borrow so
            // the secondary-index update below doesn't fight over `self`).
            {
                let rows_clone = Arc::clone(&self.rows);
                let mut row_data = rows_clone.lock().expect("rows mutex poisoned");
                let cell = row_data.get_mut(col_name).ok_or_else(|| {
                    SQLRiteError::Internal(format!("Row storage missing for column '{col_name}'"))
                })?;

                match (cell, &value) {
                    (Row::Integer(map), Some(Value::Integer(v))) => {
                        map.insert(rowid, *v as i32);
                    }
                    (Row::Integer(_), None) => {
                        return Err(SQLRiteError::Internal(format!(
                            "Integer column '{col_name}' cannot store NULL — corrupt cell?"
                        )));
                    }
                    (Row::Text(map), Some(Value::Text(s))) => {
                        map.insert(rowid, s.clone());
                    }
                    (Row::Text(map), None) => {
                        // Matches the on-insert convention: NULL in Text
                        // storage is represented by the literal "Null"
                        // sentinel and not added to the index.
                        map.insert(rowid, "Null".to_string());
                    }
                    (Row::Real(map), Some(Value::Real(v))) => {
                        map.insert(rowid, *v as f32);
                    }
                    (Row::Real(_), None) => {
                        return Err(SQLRiteError::Internal(format!(
                            "Real column '{col_name}' cannot store NULL — corrupt cell?"
                        )));
                    }
                    (Row::Bool(map), Some(Value::Bool(v))) => {
                        map.insert(rowid, *v);
                    }
                    (Row::Bool(_), None) => {
                        return Err(SQLRiteError::Internal(format!(
                            "Bool column '{col_name}' cannot store NULL — corrupt cell?"
                        )));
                    }
                    (row, v) => {
                        return Err(SQLRiteError::Internal(format!(
                            "Type mismatch restoring column '{col_name}': storage {row:?} vs value {v:?}"
                        )));
                    }
                }
            }

            // Maintain the secondary index (if any). NULL values are skipped
            // by `insert`, matching the "NULL is not indexed" convention.
            if let Some(v) = &value {
                if let Some(idx) = self.index_for_column_mut(col_name) {
                    idx.insert(v, rowid)?;
                }
            }
        }

        if rowid > self.last_rowid {
            self.last_rowid = rowid;
        }
        Ok(())
    }

    /// Extracts a row as an ordered `Vec<Option<Value>>` matching the column
    /// declaration order. Returns `None` entries for columns that hold NULL.
    /// Used by `save_database` to turn a table's in-memory state into cells.
    pub fn extract_row(&self, rowid: i64) -> Vec<Option<Value>> {
        self.columns
            .iter()
            .map(|c| match self.get_value(&c.column_name, rowid) {
                Some(Value::Null) => None,
                Some(v) => Some(v),
                None => None,
            })
            .collect()
    }

    /// Overwrites the cell at `(column, rowid)` with `new_val`. Enforces the
    /// column's datatype and UNIQUE constraint, and updates any secondary
    /// index.
    ///
    /// Returns `Err` if the column doesn't exist, the value type is incompatible,
    /// or writing would violate UNIQUE.
    pub fn set_value(&mut self, column: &str, rowid: i64, new_val: Value) -> Result<()> {
        let col_index = self
            .columns
            .iter()
            .position(|c| c.column_name == column)
            .ok_or_else(|| SQLRiteError::General(format!("Column '{column}' not found")))?;

        // No-op write — keep storage exactly the same.
        let current = self.get_value(column, rowid);
        if current.as_ref() == Some(&new_val) {
            return Ok(());
        }

        // Enforce UNIQUE. Prefer an O(log N) index probe if we have one;
        // fall back to a full column scan otherwise (Real/Bool UNIQUE
        // columns, which don't get auto-indexed).
        if self.columns[col_index].is_unique && !matches!(new_val, Value::Null) {
            if let Some(idx) = self.index_for_column(column) {
                for other in idx.lookup(&new_val) {
                    if other != rowid {
                        return Err(SQLRiteError::General(format!(
                            "UNIQUE constraint violated for column '{column}'"
                        )));
                    }
                }
            } else {
                for other in self.rowids() {
                    if other == rowid {
                        continue;
                    }
                    if self.get_value(column, other).as_ref() == Some(&new_val) {
                        return Err(SQLRiteError::General(format!(
                            "UNIQUE constraint violated for column '{column}'"
                        )));
                    }
                }
            }
        }

        // Drop the old index entry before writing the new value, so the
        // post-write index insert doesn't clash with the previous state.
        if let Some(old) = current {
            if let Some(idx) = self.index_for_column_mut(column) {
                idx.remove(&old, rowid);
            }
        }

        // Write into the column's Row, type-checking against the declared DataType.
        let declared = &self.columns[col_index].datatype;
        {
            let rows_clone = Arc::clone(&self.rows);
            let mut row_data = rows_clone.lock().expect("rows mutex poisoned");
            let cell = row_data.get_mut(column).ok_or_else(|| {
                SQLRiteError::Internal(format!("Row storage missing for column '{column}'"))
            })?;

            match (cell, &new_val, declared) {
                (Row::Integer(m), Value::Integer(v), _) => {
                    m.insert(rowid, *v as i32);
                }
                (Row::Real(m), Value::Real(v), _) => {
                    m.insert(rowid, *v as f32);
                }
                (Row::Real(m), Value::Integer(v), _) => {
                    m.insert(rowid, *v as f32);
                }
                (Row::Text(m), Value::Text(v), _) => {
                    m.insert(rowid, v.clone());
                }
                (Row::Bool(m), Value::Bool(v), _) => {
                    m.insert(rowid, *v);
                }
                // NULL writes: store the sentinel "Null" string for Text; for other
                // types we leave storage as-is since those BTreeMaps can't hold NULL today.
                (Row::Text(m), Value::Null, _) => {
                    m.insert(rowid, "Null".to_string());
                }
                (_, new, dt) => {
                    return Err(SQLRiteError::General(format!(
                        "Type mismatch: cannot assign {} to column '{column}' of type {dt}",
                        new.to_display_string()
                    )));
                }
            }
        }

        // Maintain the secondary index, if any. NULL values are skipped by
        // insert per convention.
        if !matches!(new_val, Value::Null) {
            if let Some(idx) = self.index_for_column_mut(column) {
                idx.insert(&new_val, rowid)?;
            }
        }

        Ok(())
    }

    /// Returns an immutable reference of `sql::db::table::Column` if the table contains a
    /// column with the specified key as a column name.
    ///
    #[allow(dead_code)]
    pub fn get_column(&mut self, column_name: String) -> Result<&Column> {
        if let Some(column) = self
            .columns
            .iter()
            .filter(|c| c.column_name == column_name)
            .collect::<Vec<&Column>>()
            .first()
        {
            Ok(column)
        } else {
            Err(SQLRiteError::General(String::from("Column not found.")))
        }
    }

    /// Validates if columns and values being inserted violate the UNIQUE constraint.
    /// PRIMARY KEY columns are automatically UNIQUE. Uses the corresponding
    /// secondary index when one exists (O(log N) lookup); falls back to a
    /// linear scan for indexable-but-not-indexed situations (e.g. a Real
    /// UNIQUE column — Real isn't in the auto-indexed set).
    pub fn validate_unique_constraint(
        &mut self,
        cols: &Vec<String>,
        values: &Vec<String>,
    ) -> Result<()> {
        for (idx, name) in cols.iter().enumerate() {
            let column = self
                .columns
                .iter()
                .find(|c| &c.column_name == name)
                .ok_or_else(|| SQLRiteError::General(format!("Column '{name}' not found")))?;
            if !column.is_unique {
                continue;
            }
            let datatype = &column.datatype;
            let val = &values[idx];

            // Parse the string value into a runtime Value according to the
            // declared column type. If parsing fails the caller's insert
            // would also fail with the same error; surface it here so we
            // don't emit a misleading "unique OK" on bad input.
            let parsed = match datatype {
                DataType::Integer => val.parse::<i64>().map(Value::Integer).map_err(|_| {
                    SQLRiteError::General(format!(
                        "Type mismatch: expected INTEGER for column '{name}', got '{val}'"
                    ))
                })?,
                DataType::Text => Value::Text(val.clone()),
                DataType::Real => val.parse::<f64>().map(Value::Real).map_err(|_| {
                    SQLRiteError::General(format!(
                        "Type mismatch: expected REAL for column '{name}', got '{val}'"
                    ))
                })?,
                DataType::Bool => val.parse::<bool>().map(Value::Bool).map_err(|_| {
                    SQLRiteError::General(format!(
                        "Type mismatch: expected BOOL for column '{name}', got '{val}'"
                    ))
                })?,
                DataType::None | DataType::Invalid => {
                    return Err(SQLRiteError::Internal(format!(
                        "column '{name}' has an unsupported datatype"
                    )));
                }
            };

            if let Some(secondary) = self.index_for_column(name) {
                if secondary.would_violate_unique(&parsed) {
                    return Err(SQLRiteError::General(format!(
                        "UNIQUE constraint violated for column '{name}': value '{val}' already exists"
                    )));
                }
            } else {
                // No secondary index (Real / Bool UNIQUE). Linear scan.
                for other in self.rowids() {
                    if self.get_value(name, other).as_ref() == Some(&parsed) {
                        return Err(SQLRiteError::General(format!(
                            "UNIQUE constraint violated for column '{name}': value '{val}' already exists"
                        )));
                    }
                }
            }
        }
        Ok(())
    }

    /// Inserts all VALUES in its approprieta COLUMNS, using the ROWID an embedded INDEX on all ROWS
    /// Every `Table` keeps track of the `last_rowid` in order to facilitate what the next one would be.
    /// One limitation of this data structure is that we can only have one write transaction at a time, otherwise
    /// we could have a race condition on the last_rowid.
    ///
    /// Since we are loosely modeling after SQLite, this is also a limitation of SQLite (allowing only one write transcation at a time),
    /// So we are good. :)
    ///
    /// Returns `Err` (leaving the table unchanged) when the user supplies an
    /// incompatibly-typed value — no more panics on bad input.
    pub fn insert_row(&mut self, cols: &Vec<String>, values: &Vec<String>) -> Result<()> {
        let mut next_rowid = self.last_rowid + 1;

        // Auto-assign INTEGER PRIMARY KEY when the user omits it; otherwise
        // adopt the supplied value as the new rowid.
        if self.primary_key != "-1" {
            if !cols.iter().any(|col| col == &self.primary_key) {
                // Write the auto-assigned PK into row storage, then sync
                // the secondary index.
                let val = next_rowid as i32;
                let wrote_integer = {
                    let rows_clone = Arc::clone(&self.rows);
                    let mut row_data = rows_clone.lock().expect("rows mutex poisoned");
                    let table_col_data = row_data.get_mut(&self.primary_key).ok_or_else(|| {
                        SQLRiteError::Internal(format!(
                            "Row storage missing for primary key column '{}'",
                            self.primary_key
                        ))
                    })?;
                    match table_col_data {
                        Row::Integer(tree) => {
                            tree.insert(next_rowid, val);
                            true
                        }
                        _ => false, // non-integer PK: auto-assign is a no-op
                    }
                };
                if wrote_integer {
                    let pk = self.primary_key.clone();
                    if let Some(idx) = self.index_for_column_mut(&pk) {
                        idx.insert(&Value::Integer(val as i64), next_rowid)?;
                    }
                }
            } else {
                for i in 0..cols.len() {
                    if cols[i] == self.primary_key {
                        let val = &values[i];
                        next_rowid = val.parse::<i64>().map_err(|_| {
                            SQLRiteError::General(format!(
                                "Type mismatch: PRIMARY KEY column '{}' expects INTEGER, got '{val}'",
                                self.primary_key
                            ))
                        })?;
                    }
                }
            }
        }

        // For every table column, either pick the supplied value or pad with NULL
        // so that every column's BTreeMap keeps the same rowid keyset.
        let column_names = self
            .columns
            .iter()
            .map(|col| col.column_name.to_string())
            .collect::<Vec<String>>();
        let mut j: usize = 0;
        for i in 0..column_names.len() {
            let mut val = String::from("Null");
            let key = &column_names[i];

            if let Some(supplied_key) = cols.get(j) {
                if supplied_key == &column_names[i] {
                    val = values[j].to_string();
                    j += 1;
                } else if self.primary_key == column_names[i] {
                    // PK already stored in the auto-assign branch above.
                    continue;
                }
            } else if self.primary_key == column_names[i] {
                continue;
            }

            // Step 1: write into row storage and compute the typed Value
            // we'll hand to the secondary index (if any).
            let typed_value: Option<Value> = {
                let rows_clone = Arc::clone(&self.rows);
                let mut row_data = rows_clone.lock().expect("rows mutex poisoned");
                let table_col_data = row_data.get_mut(key).ok_or_else(|| {
                    SQLRiteError::Internal(format!("Row storage missing for column '{key}'"))
                })?;

                match table_col_data {
                    Row::Integer(tree) => {
                        let parsed = val.parse::<i32>().map_err(|_| {
                            SQLRiteError::General(format!(
                                "Type mismatch: expected INTEGER for column '{key}', got '{val}'"
                            ))
                        })?;
                        tree.insert(next_rowid, parsed);
                        Some(Value::Integer(parsed as i64))
                    }
                    Row::Text(tree) => {
                        tree.insert(next_rowid, val.to_string());
                        // "Null" sentinel stays out of the index — it isn't a
                        // real user value.
                        if val != "Null" {
                            Some(Value::Text(val.to_string()))
                        } else {
                            None
                        }
                    }
                    Row::Real(tree) => {
                        let parsed = val.parse::<f32>().map_err(|_| {
                            SQLRiteError::General(format!(
                                "Type mismatch: expected REAL for column '{key}', got '{val}'"
                            ))
                        })?;
                        tree.insert(next_rowid, parsed);
                        Some(Value::Real(parsed as f64))
                    }
                    Row::Bool(tree) => {
                        let parsed = val.parse::<bool>().map_err(|_| {
                            SQLRiteError::General(format!(
                                "Type mismatch: expected BOOL for column '{key}', got '{val}'"
                            ))
                        })?;
                        tree.insert(next_rowid, parsed);
                        Some(Value::Bool(parsed))
                    }
                    Row::None => {
                        return Err(SQLRiteError::Internal(format!(
                            "Column '{key}' has no row storage"
                        )));
                    }
                }
            };

            // Step 2: maintain the secondary index (if any). insert() is a
            // no-op for Value::Null and cheap for other value kinds.
            if let Some(v) = typed_value {
                if let Some(idx) = self.index_for_column_mut(key) {
                    idx.insert(&v, next_rowid)?;
                }
            }
        }
        self.last_rowid = next_rowid;
        Ok(())
    }

    /// Print the table schema to standard output in a pretty formatted way.
    ///
    /// # Example
    ///
    /// ```text
    /// let table = Table::new(payload);
    /// table.print_table_schema();
    ///
    /// Prints to standard output:
    ///    +-------------+-----------+-------------+--------+----------+
    ///    | Column Name | Data Type | PRIMARY KEY | UNIQUE | NOT NULL |
    ///    +-------------+-----------+-------------+--------+----------+
    ///    | id          | Integer   | true        | true   | true     |
    ///    +-------------+-----------+-------------+--------+----------+
    ///    | name        | Text      | false       | true   | false    |
    ///    +-------------+-----------+-------------+--------+----------+
    ///    | email       | Text      | false       | false  | false    |
    ///    +-------------+-----------+-------------+--------+----------+
    /// ```
    ///
    pub fn print_table_schema(&self) -> Result<usize> {
        let mut table = PrintTable::new();
        table.add_row(row![
            "Column Name",
            "Data Type",
            "PRIMARY KEY",
            "UNIQUE",
            "NOT NULL"
        ]);

        for col in &self.columns {
            table.add_row(row![
                col.column_name,
                col.datatype,
                col.is_pk,
                col.is_unique,
                col.not_null
            ]);
        }

        table.printstd();
        Ok(table.len() * 2 + 1)
    }

    /// Print the table data to standard output in a pretty formatted way.
    ///
    /// # Example
    ///
    /// ```text
    /// let db_table = db.get_table_mut(table_name.to_string()).unwrap();
    /// db_table.print_table_data();
    ///
    /// Prints to standard output:
    ///     +----+---------+------------------------+
    ///     | id | name    | email                  |
    ///     +----+---------+------------------------+
    ///     | 1  | "Jack"  | "jack@mail.com"        |
    ///     +----+---------+------------------------+
    ///     | 10 | "Bob"   | "bob@main.com"         |
    ///     +----+---------+------------------------+
    ///     | 11 | "Bill"  | "bill@main.com"        |
    ///     +----+---------+------------------------+
    /// ```
    ///
    pub fn print_table_data(&self) {
        let mut print_table = PrintTable::new();

        let column_names = self
            .columns
            .iter()
            .map(|col| col.column_name.to_string())
            .collect::<Vec<String>>();

        let header_row = PrintRow::new(
            column_names
                .iter()
                .map(|col| PrintCell::new(col))
                .collect::<Vec<PrintCell>>(),
        );

        let rows_clone = Arc::clone(&self.rows);
        let row_data = rows_clone.lock().expect("rows mutex poisoned");
        let first_col_data = row_data
            .get(&self.columns.first().unwrap().column_name)
            .unwrap();
        let num_rows = first_col_data.count();
        let mut print_table_rows: Vec<PrintRow> = vec![PrintRow::new(vec![]); num_rows];

        for col_name in &column_names {
            let col_val = row_data
                .get(col_name)
                .expect("Can't find any rows with the given column");
            let columns: Vec<String> = col_val.get_serialized_col_data();

            for i in 0..num_rows {
                if let Some(cell) = &columns.get(i) {
                    print_table_rows[i].add_cell(PrintCell::new(cell));
                } else {
                    print_table_rows[i].add_cell(PrintCell::new(""));
                }
            }
        }

        print_table.add_row(header_row);
        for row in print_table_rows {
            print_table.add_row(row);
        }

        print_table.printstd();
    }
}

/// The schema for each SQL column in every table.
///
/// Per-column index state moved to `Table::secondary_indexes` in Phase 3e —
/// a single `Column` describes the declared schema (name, type, constraints)
/// and nothing more.
#[derive(PartialEq, Debug, Clone)]
pub struct Column {
    pub column_name: String,
    pub datatype: DataType,
    pub is_pk: bool,
    pub not_null: bool,
    pub is_unique: bool,
}

impl Column {
    pub fn new(
        name: String,
        datatype: String,
        is_pk: bool,
        not_null: bool,
        is_unique: bool,
    ) -> Self {
        let dt = DataType::new(datatype);
        Column {
            column_name: name,
            datatype: dt,
            is_pk,
            not_null,
            is_unique,
        }
    }
}

/// The schema for each SQL row in every table is represented in memory
/// by following structure
///
/// This is an enum representing each of the available types organized in a BTreeMap
/// data structure, using the ROWID and key and each corresponding type as value
#[derive(PartialEq, Debug, Clone)]
pub enum Row {
    Integer(BTreeMap<i64, i32>),
    Text(BTreeMap<i64, String>),
    Real(BTreeMap<i64, f32>),
    Bool(BTreeMap<i64, bool>),
    None,
}

impl Row {
    fn get_serialized_col_data(&self) -> Vec<String> {
        match self {
            Row::Integer(cd) => cd.values().map(|v| v.to_string()).collect(),
            Row::Real(cd) => cd.values().map(|v| v.to_string()).collect(),
            Row::Text(cd) => cd.values().map(|v| v.to_string()).collect(),
            Row::Bool(cd) => cd.values().map(|v| v.to_string()).collect(),
            Row::None => panic!("Found None in columns"),
        }
    }

    fn count(&self) -> usize {
        match self {
            Row::Integer(cd) => cd.len(),
            Row::Real(cd) => cd.len(),
            Row::Text(cd) => cd.len(),
            Row::Bool(cd) => cd.len(),
            Row::None => panic!("Found None in columns"),
        }
    }

    /// Every column's BTreeMap is keyed by ROWID. All columns share the same keyset
    /// after an INSERT (missing columns are padded), so any column's keys are a valid
    /// iteration of the table's rowids.
    pub fn rowids(&self) -> Vec<i64> {
        match self {
            Row::Integer(m) => m.keys().copied().collect(),
            Row::Text(m) => m.keys().copied().collect(),
            Row::Real(m) => m.keys().copied().collect(),
            Row::Bool(m) => m.keys().copied().collect(),
            Row::None => vec![],
        }
    }

    pub fn get(&self, rowid: i64) -> Option<Value> {
        match self {
            Row::Integer(m) => m.get(&rowid).map(|v| Value::Integer(i64::from(*v))),
            // INSERT stores the literal string "Null" in Text columns that were omitted
            // from the query — re-map that back to a real NULL on read.
            Row::Text(m) => m.get(&rowid).map(|v| {
                if v == "Null" {
                    Value::Null
                } else {
                    Value::Text(v.clone())
                }
            }),
            Row::Real(m) => m.get(&rowid).map(|v| Value::Real(f64::from(*v))),
            Row::Bool(m) => m.get(&rowid).map(|v| Value::Bool(*v)),
            Row::None => None,
        }
    }
}

/// Runtime value produced by query execution. Separate from the on-disk `Row` enum
/// so the executor can carry typed values (including NULL) across operators.
#[derive(Debug, Clone, PartialEq)]
pub enum Value {
    Integer(i64),
    Text(String),
    Real(f64),
    Bool(bool),
    Null,
}

impl Value {
    pub fn to_display_string(&self) -> String {
        match self {
            Value::Integer(v) => v.to_string(),
            Value::Text(s) => s.clone(),
            Value::Real(f) => f.to_string(),
            Value::Bool(b) => b.to_string(),
            Value::Null => String::from("NULL"),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use sqlparser::dialect::SQLiteDialect;
    use sqlparser::parser::Parser;

    #[test]
    fn datatype_display_trait_test() {
        let integer = DataType::Integer;
        let text = DataType::Text;
        let real = DataType::Real;
        let boolean = DataType::Bool;
        let none = DataType::None;
        let invalid = DataType::Invalid;

        assert_eq!(format!("{}", integer), "Integer");
        assert_eq!(format!("{}", text), "Text");
        assert_eq!(format!("{}", real), "Real");
        assert_eq!(format!("{}", boolean), "Boolean");
        assert_eq!(format!("{}", none), "None");
        assert_eq!(format!("{}", invalid), "Invalid");
    }

    #[test]
    fn create_new_table_test() {
        let query_statement = "CREATE TABLE contacts (
            id INTEGER PRIMARY KEY,
            first_name TEXT NOT NULL,
            last_name TEXT NOT NULl,
            email TEXT NOT NULL UNIQUE,
            active BOOL,
            score REAL
        );";
        let dialect = SQLiteDialect {};
        let mut ast = Parser::parse_sql(&dialect, query_statement).unwrap();
        if ast.len() > 1 {
            panic!("Expected a single query statement, but there are more then 1.")
        }
        let query = ast.pop().unwrap();

        let create_query = CreateQuery::new(&query).unwrap();

        let table = Table::new(create_query);

        assert_eq!(table.columns.len(), 6);
        assert_eq!(table.last_rowid, 0);

        let id_column = "id".to_string();
        if let Some(column) = table
            .columns
            .iter()
            .filter(|c| c.column_name == id_column)
            .collect::<Vec<&Column>>()
            .first()
        {
            assert!(column.is_pk);
            assert_eq!(column.datatype, DataType::Integer);
        } else {
            panic!("column not found");
        }
    }

    #[test]
    fn print_table_schema_test() {
        let query_statement = "CREATE TABLE contacts (
            id INTEGER PRIMARY KEY,
            first_name TEXT NOT NULL,
            last_name TEXT NOT NULl
        );";
        let dialect = SQLiteDialect {};
        let mut ast = Parser::parse_sql(&dialect, query_statement).unwrap();
        if ast.len() > 1 {
            panic!("Expected a single query statement, but there are more then 1.")
        }
        let query = ast.pop().unwrap();

        let create_query = CreateQuery::new(&query).unwrap();

        let table = Table::new(create_query);
        let lines_printed = table.print_table_schema();
        assert_eq!(lines_printed, Ok(9));
    }
}