// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! SQL Abstract Syntax Tree (AST) types

mod data_type;
mod ddl;
mod expression;
mod operator;
mod query;
mod statement;
mod value;
#[cfg(not(feature = "std"))]
use alloc::{
    boxed::Box,
    string::{String, ToString},
    vec::Vec,
};
use core::fmt;
pub use ddl::*;
pub use expression::*;
pub use statement::*;

#[cfg(feature = "serde")]
use serde::{Deserialize, Serialize};

pub use self::data_type::DataType;
pub use self::ddl::{
    AlterTableOperation, ColumnDef, ColumnOption, ColumnOptionDef, ReferentialAction,
    TableConstraint,
};
pub use self::operator::{BinaryOperator, UnaryOperator};
pub use self::query::{
    Cte, Fetch, Join, JoinConstraint, JoinOperator, LateralView, Offset, OffsetRows, OrderByExpr,
    Query, Select, SelectItem, SetExpr, SetOperator, TableAlias, TableFactor, TableWithJoins, Top,
    Values, With,
};
pub use self::value::{DateTimeField, TrimWhereField, Value};

struct DisplaySeparated<'a, T>
where
    T: fmt::Display,
{
    slice: &'a [T],
    sep: &'static str,
}

impl<'a, T> fmt::Display for DisplaySeparated<'a, T>
where
    T: fmt::Display,
{
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let mut delim = "";
        for t in self.slice {
            write!(f, "{}", delim)?;
            delim = self.sep;
            write!(f, "{}", t)?;
        }
        Ok(())
    }
}

fn display_separated<'a, T>(slice: &'a [T], sep: &'static str) -> DisplaySeparated<'a, T>
where
    T: fmt::Display,
{
    DisplaySeparated { slice, sep }
}

fn display_comma_separated<T>(slice: &[T]) -> DisplaySeparated<'_, T>
where
    T: fmt::Display,
{
    DisplaySeparated { slice, sep: ", " }
}

/// An identifier, decomposed into its value or character data and the quote style.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct Ident {
    /// The value of the identifier without quotes.
    pub value: String,
    /// The starting quote if any. Valid quote characters are the single quote,
    /// double quote, backtick, and opening square bracket.
    pub quote_style: Option<char>,
}

impl Ident {
    /// Create a new identifier with the given value and no quotes.
    pub fn new<S>(value: S) -> Self
    where
        S: Into<String>,
    {
        Ident {
            value: value.into(),
            quote_style: None,
        }
    }

    /// Create a new quoted identifier with the given quote and value. This function
    /// panics if the given quote is not a valid quote character.
    pub fn with_quote<S>(quote: char, value: S) -> Self
    where
        S: Into<String>,
    {
        assert!(quote == '\'' || quote == '"' || quote == '`' || quote == '[');
        Ident {
            value: value.into(),
            quote_style: Some(quote),
        }
    }
}

impl From<&str> for Ident {
    fn from(value: &str) -> Self {
        Ident {
            value: value.to_string(),
            quote_style: None,
        }
    }
}

impl fmt::Display for Ident {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self.quote_style {
            Some(q) if q == '"' || q == '\'' || q == '`' => write!(f, "{}{}{}", q, self.value, q),
            Some(q) if q == '[' => write!(f, "[{}]", self.value),
            None => f.write_str(&self.value),
            _ => panic!("unexpected quote style"),
        }
    }
}

/// A name of a table, view, custom type, etc., possibly multi-part, i.e. db.schema.obj
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct ObjectName(pub Vec<Ident>);

impl fmt::Display for ObjectName {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", display_separated(&self.0, "."))
    }
}

/// A window specification (i.e. `OVER (PARTITION BY .. ORDER BY .. etc.)`)
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct WindowSpec {
    pub partition_by: Vec<Expr>,
    pub order_by: Vec<OrderByExpr>,
    pub window_frame: Option<WindowFrame>,
}

impl fmt::Display for WindowSpec {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let mut delim = "";
        if !self.partition_by.is_empty() {
            delim = " ";
            write!(
                f,
                "PARTITION BY {}",
                display_comma_separated(&self.partition_by)
            )?;
        }
        if !self.order_by.is_empty() {
            f.write_str(delim)?;
            delim = " ";
            write!(f, "ORDER BY {}", display_comma_separated(&self.order_by))?;
        }
        if let Some(window_frame) = &self.window_frame {
            if let Some(end_bound) = &window_frame.end_bound {
                f.write_str(delim)?;
                write!(
                    f,
                    "{} BETWEEN {} AND {}",
                    window_frame.units, window_frame.start_bound, end_bound
                )?;
            } else {
                f.write_str(delim)?;
                write!(f, "{} {}", window_frame.units, window_frame.start_bound)?;
            }
        }
        Ok(())
    }
}

/// Specifies the data processed by a window function, e.g.
/// `RANGE UNBOUNDED PRECEDING` or `ROWS BETWEEN 5 PRECEDING AND CURRENT ROW`.
///
/// Note: The parser does not validate the specified bounds; the caller should
/// reject invalid bounds like `ROWS UNBOUNDED FOLLOWING` before execution.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct WindowFrame {
    pub units: WindowFrameUnits,
    pub start_bound: WindowFrameBound,
    /// The right bound of the `BETWEEN .. AND` clause. The end bound of `None`
    /// indicates the shorthand form (e.g. `ROWS 1 PRECEDING`), which must
    /// behave the same as `end_bound = WindowFrameBound::CurrentRow`.
    pub end_bound: Option<WindowFrameBound>,
    // TBD: EXCLUDE
}

impl Default for WindowFrame {
    /// returns default value for window frame
    ///
    /// see https://www.sqlite.org/windowfunctions.html#frame_specifications
    fn default() -> Self {
        Self {
            units: WindowFrameUnits::Range,
            start_bound: WindowFrameBound::Preceding(None),
            end_bound: None,
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum WindowFrameUnits {
    Rows,
    Range,
    Groups,
}

impl fmt::Display for WindowFrameUnits {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.write_str(match self {
            WindowFrameUnits::Rows => "ROWS",
            WindowFrameUnits::Range => "RANGE",
            WindowFrameUnits::Groups => "GROUPS",
        })
    }
}

/// Specifies [WindowFrame]'s `start_bound` and `end_bound`
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum WindowFrameBound {
    /// `CURRENT ROW`
    CurrentRow,
    /// `<N> PRECEDING` or `UNBOUNDED PRECEDING`
    Preceding(Option<u64>),
    /// `<N> FOLLOWING` or `UNBOUNDED FOLLOWING`.
    Following(Option<u64>),
}

impl fmt::Display for WindowFrameBound {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            WindowFrameBound::CurrentRow => f.write_str("CURRENT ROW"),
            WindowFrameBound::Preceding(None) => f.write_str("UNBOUNDED PRECEDING"),
            WindowFrameBound::Following(None) => f.write_str("UNBOUNDED FOLLOWING"),
            WindowFrameBound::Preceding(Some(n)) => write!(f, "{} PRECEDING", n),
            WindowFrameBound::Following(Some(n)) => write!(f, "{} FOLLOWING", n),
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum AddDropSync {
    ADD,
    DROP,
    SYNC,
}

impl fmt::Display for AddDropSync {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            AddDropSync::SYNC => f.write_str("SYNC PARTITIONS"),
            AddDropSync::DROP => f.write_str("DROP PARTITIONS"),
            AddDropSync::ADD => f.write_str("ADD PARTITIONS"),
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum ShowCreateObject {
    Event,
    Function,
    Procedure,
    Table,
    Trigger,
}

impl fmt::Display for ShowCreateObject {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            ShowCreateObject::Event => f.write_str("EVENT"),
            ShowCreateObject::Function => f.write_str("FUNCTION"),
            ShowCreateObject::Procedure => f.write_str("PROCEDURE"),
            ShowCreateObject::Table => f.write_str("TABLE"),
            ShowCreateObject::Trigger => f.write_str("TRIGGER"),
        }
    }
}

/// SQL assignment `foo = expr` as used in SQLUpdate
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct Assignment {
    pub id: Ident,
    pub value: Expr,
}

impl fmt::Display for Assignment {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{} = {}", self.id, self.value)
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum FunctionArg {
    Named { name: Ident, arg: Expr },
    Unnamed(Expr),
}

impl fmt::Display for FunctionArg {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            FunctionArg::Named { name, arg } => write!(f, "{} => {}", name, arg),
            FunctionArg::Unnamed(unnamed_arg) => write!(f, "{}", unnamed_arg),
        }
    }
}

/// A function call
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct Function {
    pub name: ObjectName,
    pub args: Vec<FunctionArg>,
    pub over: Option<WindowSpec>,
    // aggregate functions may specify eg `COUNT(DISTINCT x)`
    pub distinct: bool,
}

impl fmt::Display for Function {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(
            f,
            "{}({}{})",
            self.name,
            if self.distinct { "DISTINCT " } else { "" },
            display_comma_separated(&self.args),
        )?;
        if let Some(o) = &self.over {
            write!(f, " OVER ({})", o)?;
        }
        Ok(())
    }
}

/// External table's available file format
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum FileFormat {
    TEXTFILE,
    SEQUENCEFILE,
    ORC,
    PARQUET,
    AVRO,
    RCFILE,
    JSONFILE,
}

impl fmt::Display for FileFormat {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use self::FileFormat::*;
        f.write_str(match self {
            TEXTFILE => "TEXTFILE",
            SEQUENCEFILE => "SEQUENCEFILE",
            ORC => "ORC",
            PARQUET => "PARQUET",
            AVRO => "AVRO",
            RCFILE => "RCFILE",
            JSONFILE => "JSONFILE",
        })
    }
}

/// A `LISTAGG` invocation `LISTAGG( [ DISTINCT ] <expr>[, <separator> ] [ON OVERFLOW <on_overflow>] ) )
/// [ WITHIN GROUP (ORDER BY <within_group1>[, ...] ) ]`
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct ListAgg {
    pub distinct: bool,
    pub expr: Box<Expr>,
    pub separator: Option<Box<Expr>>,
    pub on_overflow: Option<ListAggOnOverflow>,
    pub within_group: Vec<OrderByExpr>,
}

impl fmt::Display for ListAgg {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(
            f,
            "LISTAGG({}{}",
            if self.distinct { "DISTINCT " } else { "" },
            self.expr
        )?;
        if let Some(separator) = &self.separator {
            write!(f, ", {}", separator)?;
        }
        if let Some(on_overflow) = &self.on_overflow {
            write!(f, "{}", on_overflow)?;
        }
        write!(f, ")")?;
        if !self.within_group.is_empty() {
            write!(
                f,
                " WITHIN GROUP (ORDER BY {})",
                display_comma_separated(&self.within_group)
            )?;
        }
        Ok(())
    }
}

/// The `ON OVERFLOW` clause of a LISTAGG invocation
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum ListAggOnOverflow {
    /// `ON OVERFLOW ERROR`
    Error,

    /// `ON OVERFLOW TRUNCATE [ <filler> ] WITH[OUT] COUNT`
    Truncate {
        filler: Option<Box<Expr>>,
        with_count: bool,
    },
}

impl fmt::Display for ListAggOnOverflow {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, " ON OVERFLOW")?;
        match self {
            ListAggOnOverflow::Error => write!(f, " ERROR"),
            ListAggOnOverflow::Truncate { filler, with_count } => {
                write!(f, " TRUNCATE")?;
                if let Some(filler) = filler {
                    write!(f, " {}", filler)?;
                }
                if *with_count {
                    write!(f, " WITH")?;
                } else {
                    write!(f, " WITHOUT")?;
                }
                write!(f, " COUNT")
            }
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum ObjectType {
    Table,
    View,
    Index,
    Schema,
}

impl fmt::Display for ObjectType {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.write_str(match self {
            ObjectType::Table => "TABLE",
            ObjectType::View => "VIEW",
            ObjectType::Index => "INDEX",
            ObjectType::Schema => "SCHEMA",
        })
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum HiveDistributionStyle {
    PARTITIONED {
        columns: Vec<ColumnDef>,
    },
    CLUSTERED {
        columns: Vec<Ident>,
        sorted_by: Vec<ColumnDef>,
        num_buckets: i32,
    },
    SKEWED {
        columns: Vec<ColumnDef>,
        on: Vec<ColumnDef>,
        stored_as_directories: bool,
    },
    NONE,
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum HiveRowFormat {
    SERDE { class: String },
    DELIMITED,
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum HiveIOFormat {
    IOF {
        input_format: Expr,
        output_format: Expr,
    },
    FileFormat {
        format: FileFormat,
    },
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct HiveFormat {
    pub row_format: Option<HiveRowFormat>,
    pub storage: Option<HiveIOFormat>,
    pub location: Option<String>,
}

impl Default for HiveFormat {
    fn default() -> Self {
        HiveFormat {
            row_format: None,
            location: None,
            storage: None,
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct SqlOption {
    pub name: Ident,
    pub value: Value,
}

impl fmt::Display for SqlOption {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{} = {}", self.name, self.value)
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum TransactionMode {
    AccessMode(TransactionAccessMode),
    IsolationLevel(TransactionIsolationLevel),
}

impl fmt::Display for TransactionMode {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use TransactionMode::*;
        match self {
            AccessMode(access_mode) => write!(f, "{}", access_mode),
            IsolationLevel(iso_level) => write!(f, "ISOLATION LEVEL {}", iso_level),
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum TransactionAccessMode {
    ReadOnly,
    ReadWrite,
}

impl fmt::Display for TransactionAccessMode {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use TransactionAccessMode::*;
        f.write_str(match self {
            ReadOnly => "READ ONLY",
            ReadWrite => "READ WRITE",
        })
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum TransactionIsolationLevel {
    ReadUncommitted,
    ReadCommitted,
    RepeatableRead,
    Serializable,
}

impl fmt::Display for TransactionIsolationLevel {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use TransactionIsolationLevel::*;
        f.write_str(match self {
            ReadUncommitted => "READ UNCOMMITTED",
            ReadCommitted => "READ COMMITTED",
            RepeatableRead => "REPEATABLE READ",
            Serializable => "SERIALIZABLE",
        })
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum ShowStatementFilter {
    Like(String),
    ILike(String),
    Where(Expr),
}

impl fmt::Display for ShowStatementFilter {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use ShowStatementFilter::*;
        match self {
            Like(pattern) => write!(f, "LIKE '{}'", value::escape_single_quote_string(pattern)),
            ILike(pattern) => write!(f, "ILIKE {}", value::escape_single_quote_string(pattern)),
            Where(expr) => write!(f, "WHERE {}", expr),
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum SetVariableValue {
    Ident(Ident),
    Literal(Value),
}

impl fmt::Display for SetVariableValue {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use SetVariableValue::*;
        match self {
            Ident(ident) => write!(f, "{}", ident),
            Literal(literal) => write!(f, "{}", literal),
        }
    }
}

/// Sqlite specific syntax
///
/// https://sqlite.org/lang_conflict.html
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum SqliteOnConflict {
    Rollback,
    Abort,
    Fail,
    Ignore,
    Replace,
}

impl fmt::Display for SqliteOnConflict {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use SqliteOnConflict::*;
        match self {
            Rollback => write!(f, "ROLLBACK"),
            Abort => write!(f, "ABORT"),
            Fail => write!(f, "FAIL"),
            Ignore => write!(f, "IGNORE"),
            Replace => write!(f, "REPLACE"),
        }
    }
}

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

    #[test]
    fn test_window_frame_default() {
        let window_frame = WindowFrame::default();
        assert_eq!(WindowFrameBound::Preceding(None), window_frame.start_bound);
    }
}