use std::borrow::Cow;

use fancy_regex::{escape, Regex};
use sonic_rs::{Deserialize, Serialize};

use crate::matcher::{MatchResultTrait, TextMatcherTrait};
#[cfg(feature = "serde")]
use crate::util::serde::{serde_regex, serde_regex_list};

/// Enumeration representing different types of regex match algorithms used in text matching.
///
/// The [RegexMatchType] enum provides a way to distinguish between various match algorithms
/// that can be applied during regex pattern matching. Each variant defines a specific matching
/// strategy, allowing for flexible and tailored text matching operations.
///
/// # Variants
///
/// * [SimilarChar](RegexMatchType::Regex) - Represents a matching strategy that identifies matches based on character similarity. This type of matching is useful for finding text that is similar in character composition but not necessarily identical.
/// * [Acrostic](RegexMatchType::Acrostic) - Represents a matching strategy that identifies acrostic matches, where the matching portion of the text forms an acrostic pattern. This type of matching is particularly useful for specific types of literary analysis or word games.
/// * [Regex](RegexMatchType::Regex) - Represents a standard regex matching strategy, utilizing regular expressions to identify precise patterns within the text. This type of matching is widely used for its flexibility and power in text processing.
///
/// This enum is used within various text matching applications to specify the match type to be applied,
/// enabling the application to execute the appropriate algorithm for the desired matching criteria.
#[derive(Serialize, Deserialize, Clone, Copy, Debug, PartialEq)]
#[serde(rename_all = "snake_case")]
pub enum RegexMatchType {
    SimilarChar,
    Acrostic,
    Regex,
}

/// Represents a table containing regex patterns and their associated metadata for text matching operations.
///
/// The [RegexTable] struct is designed to encapsulate a collection of regex patterns along with relevant
/// identifiers and match type information. This structure is utilized in regex-based text matching processes
/// to organize and manage various sets of regex patterns efficiently.
///
/// # Fields
///
/// * `table_id` - A unique identifier for the regex table. This field is used to distinguish between different regex tables.
/// * `match_id` - An identifier that corresponds to the specific match operation associated with this regex table. This helps in tracking and categorizing match results.
/// * `regex_match_type` - The type of regex match algorithm being used, represented by the [RegexMatchType] enum. This field defines the matching strategy applied by the regex patterns in the table.
/// * `word_list` - A reference to a vector of string slices (`&'a Vec<&'a str>`) that represents the list of words or patterns that the regex in this table aims to match against. This collection allows the regex operations to process and match text efficiently.
///
/// # Example
///
/// ```rust
/// use matcher_rs::{RegexTable, RegexMatchType};
///
/// let word_list = vec!["example", "test", "sample"];
/// let regex_table = RegexTable {
///     table_id: 1,
///     match_id: 42,
///     regex_match_type: RegexMatchType::Regex,
///     word_list: &word_list,
/// };
///
/// println!("{:?}", regex_table);
/// ```
///
/// The example above demonstrates how to create a [RegexTable] instance, populate it with a list of words,
/// and print the structure for debugging or logging purposes.
///
/// This struct is primarily used in advanced text matching applications, where the organization and efficient
/// management of regex patterns are crucial for the performance and accuracy of the matching process.
#[derive(Debug, Clone)]
pub struct RegexTable<'a> {
    pub table_id: u32,
    pub match_id: u32,
    pub regex_match_type: RegexMatchType,
    pub word_list: &'a Vec<&'a str>,
}

/// Enum representing different types of regex pattern tables used in the [RegexMatcher].
///
/// The `RegexType` enum is utilized within `RegexPatternTable` to define the structure and behavior of the regex
/// patterns stored in each table. It supports two types of regex patterns: `StandardRegex` and `ListRegex`.
///
/// # Variants
///
/// * `StandardRegex` - Represents a table that holds a single compiled regex pattern.
///   - `regex` ([Regex]): The compiled regex pattern used for matching text.
///
/// * `ListRegex` - Represents a table that holds a list of compiled regex patterns and their corresponding words.
///   - `regex_list` ([`Vec<Regex>`]): A list of compiled regex patterns used for matching text.
///   - `word_list` ([`Vec<String>`]): A list of words corresponding to each regex pattern in `regex_list`.
///
/// # Usage
///
/// This enum enables the [RegexMatcher] to distinguish between tables that use a singular regex pattern and those
/// that use multiple patterns stored in a list. The associated data for each variant ensures that the [RegexMatcher]
/// can accurately process match operations and return results based on the specific table type.
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
enum RegexType {
    StandardRegex {
        #[cfg_attr(feature = "serde", serde(with = "serde_regex"))]
        regex: Regex,
    },
    ListRegex {
        #[cfg_attr(feature = "serde", serde(with = "serde_regex_list"))]
        regex_list: Vec<Regex>,
        word_list: Vec<String>,
    },
}

/// A structure representing a table of regex patterns used for text matching.
///
/// The `RegexPatternTable` struct is designed to hold compiled regex patterns and associated metadata,
/// allowing the [RegexMatcher] to efficiently organize and manage different sets of patterns for matching
/// text. Each `RegexPatternTable` instance corresponds to a specific regex table and contains details
/// such as a unique identifier, match identifier, and the type of regex patterns stored.
///
/// # Fields
///
/// * `table_id` - A unique identifier for the regex pattern table. This identifier distinguishes the table from other regex tables.
/// * `match_id` - A unique identifier for the match, which corresponds to the `match_id` of the [RegexTable] that contains the regex pattern.
/// * `regex_type` - The type of regex pattern table, represented by the `RegexType` enum. This field determines the structure and behavior of the regex patterns stored in the table.
///
/// The `RegexPatternTable` struct is utilized internally by the [RegexMatcher] to categorize and execute regex-based text matching operations.
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
struct RegexPatternTable {
    table_id: u32,
    match_id: u32,
    regex_type: RegexType,
}

/// Represents a result from a regex matching operation, containing metadata about the match.
///
/// The `RegexResult` structure is designed to encapsulate information about a particular regex match,
/// including the matched word or pattern, the table identifier from which the match originated, and
/// the match identifier associated with the match.
///
/// # Fields
///
/// * `word` - A [Cow<'a, str>] that holds the matched word or pattern. This field can either be a
///   borrowed string slice or an owned [String], offering flexibility in how the match result is stored.
///
/// * `table_id` - A [u32] representing the unique identifier of the regex table that produced the match result.
///   This helps in distinguishing which regex table contributed to the result, facilitating organized processing
///   and categorization of matches.
///
/// * `match_id` - A [u32] that serves as an identifier for the match. This identifier
///   is used to differentiate between match results originating from different regex tables, allowing
///   for more detailed and organized match results.
///
/// This structure is primarily utilized in text matching applications where regex patterns are used
/// to identify specific words or patterns within the target text, and the results need to be tracked
/// and processed accordingly.
#[derive(Debug, Clone)]
pub struct RegexResult<'a> {
    pub word: Cow<'a, str>,
    pub table_id: u32,
    pub match_id: u32,
}

impl MatchResultTrait<'_> for RegexResult<'_> {
    fn table_id(&self) -> u32 {
        self.table_id
    }
    fn word(&self) -> &str {
        self.word.as_ref()
    }
}

/// A structure responsible for managing and handling regex pattern tables for text matching.
///
/// The [RegexMatcher] stores a list of `RegexPatternTable` structures, each of which contains
/// regex patterns and associated metadata used for efficient text matching operations. The struct
/// provides methods to create a new instance from a list of [RegexTable] structures, as well as
/// to check for matches and process the text to produce a list of match results.
///
/// # Fields
///
/// * `regex_pattern_table_list` - A vector of `RegexPatternTable` structures that hold regex patterns
///   and associated metadata for text matching.
///
/// # Usage
///
/// This structure is used within the [RegexMatcher] to efficiently manage multiple regex patterns
/// and their corresponding match tables. It enables the [RegexMatcher] to perform text matching
/// operations and return results based on the provided regex tables.
///
/// # Example
///
/// ```
/// use matcher_rs::{RegexMatcher, RegexTable, RegexMatchType, TextMatcherTrait};
///
/// let regex_table = RegexTable {
///     table_id: 1,
///     match_id: 1,
///     regex_match_type: RegexMatchType::SimilarChar,
///     word_list: &vec!["1,一", "2,二"],
/// };
///
/// let regex_matcher = RegexMatcher::new(&vec![regex_table]);
/// assert!(regex_matcher.is_match("12"));
/// assert!(regex_matcher.is_match("一2"));
/// assert!(regex_matcher.is_match("1二"));
/// ```
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct RegexMatcher {
    regex_pattern_table_list: Vec<RegexPatternTable>,
}

impl RegexMatcher {
    /// Constructs a new [RegexMatcher] instance from a list of [RegexTable] structures.
    ///
    /// This function initializes a [RegexMatcher] by processing the provided `regex_table_list` and
    /// compiling the necessary regex patterns based on the [MatchTableType](crate::MatchTableType) for each table. The resulting
    /// [RegexMatcher] contains a list of `RegexPatternTable` structures that store compiled regex patterns
    /// and related metadata for efficient text matching operations.
    ///
    /// # Arguments
    ///
    /// * `regex_table_list` - A reference to a vector of [RegexTable] structures, each representing a table
    ///   of words or patterns along with associated metadata and match table type.
    ///
    /// # Returns
    ///
    /// A [RegexMatcher] instance containing compiled regex patterns and metadata for performing text matching
    /// based on the provided [RegexTable] structures.
    ///
    /// # Match Table Types
    ///
    /// The function handles different [RegexMatchType] variants within the [RegexTable]:
    ///
    /// * [SimilarChar](RegexMatchType::SimilarChar) - Creates a combined regex pattern by escaping each word in the word list and joining
    ///   them with a `.?` separator. The resulting pattern is stored as a `StandardRegex` type in a new
    ///   `RegexPatternTable` entry.
    ///
    /// * [Acrostic](RegexMatchType::Acrostic) - Iterates through each word in the word list, creating corresponding regex patterns to
    ///   match acrostic patterns in the text. Each pattern is prefixed with `(?:^|[\s\pP]+?)` to support
    ///   case-insensitive matching at the start of words or after punctuation. The resulting patterns and
    ///   words are stored as a `ListRegex` type in a new `RegexPatternTable` entry.
    ///
    /// * [Regex](RegexMatchType::Regex) - Treats each word in the word list as a full regex pattern and compiles it accordingly.
    ///   The compiled regex patterns and corresponding words are stored as a `ListRegex` type in a new
    ///   `RegexPatternTable` entry.
    ///
    /// # Panics
    ///
    /// This function may panic if the regex compilation fails for any of the provided patterns. Such cases
    /// should be rare, as the input is typically pre-validated to ensure proper regex syntax.
    ///
    /// # Examples
    ///
    /// ```
    /// use matcher_rs::{RegexMatcher, RegexTable, RegexMatchType, TextMatcherTrait};
    ///
    /// let regex_table = RegexTable {
    ///     table_id: 1,
    ///     match_id: 1,
    ///     regex_match_type: RegexMatchType::SimilarChar,
    ///     word_list: &vec!["1,一", "2,二"],
    /// };
    ///
    /// let regex_matcher = RegexMatcher::new(&vec![regex_table]);
    ///
    /// assert!(regex_matcher.is_match("12"));
    /// assert!(regex_matcher.is_match("一2"));
    /// assert!(regex_matcher.is_match("1二"));
    /// ```
    pub fn new(regex_table_list: &[RegexTable]) -> RegexMatcher {
        let mut regex_pattern_table_list = Vec::with_capacity(regex_table_list.len());

        for regex_table in regex_table_list {
            let size = regex_table.word_list.len();

            match regex_table.regex_match_type {
                RegexMatchType::SimilarChar => {
                    let pattern = regex_table
                        .word_list
                        .iter()
                        .map(|charstr| format!("({})", escape(charstr).replace(',', "|")))
                        .collect::<Vec<String>>()
                        .join(".?");

                    regex_pattern_table_list.push(RegexPatternTable {
                        table_id: regex_table.table_id,
                        match_id: regex_table.match_id,
                        regex_type: RegexType::StandardRegex {
                            regex: Regex::new(&pattern).unwrap(),
                        },
                    });
                }
                RegexMatchType::Acrostic => {
                    let mut word_list = Vec::with_capacity(size);
                    let mut regex_list = Vec::with_capacity(size);

                    for &word in regex_table.word_list.iter() {
                        let pattern = format!(
                            r"(?i)(?:^|[\s\pP]+?){}",
                            escape(word).replace(',', r".*?[\s\pP]+?")
                        );

                        word_list.push(word.to_owned());
                        regex_list.push(Regex::new(&pattern).unwrap());
                    }

                    regex_pattern_table_list.push(RegexPatternTable {
                        table_id: regex_table.table_id,
                        match_id: regex_table.match_id,
                        regex_type: RegexType::ListRegex {
                            regex_list,
                            word_list,
                        },
                    });
                }
                RegexMatchType::Regex => {
                    let word_list = regex_table
                        .word_list
                        .iter()
                        .map(|&word| word.to_owned())
                        .collect::<Vec<String>>();

                    regex_pattern_table_list.push(RegexPatternTable {
                        table_id: regex_table.table_id,
                        match_id: regex_table.match_id,
                        regex_type: RegexType::ListRegex {
                            regex_list: word_list
                                .iter()
                                .filter_map(|word| Regex::new(word).ok())
                                .collect(),
                            word_list,
                        },
                    });
                }
            };
        }

        RegexMatcher {
            regex_pattern_table_list,
        }
    }
}

impl<'a> TextMatcherTrait<'a, RegexResult<'a>> for RegexMatcher {
    /// Determines if the provided text matches any of the regex patterns stored in the match tables.
    ///
    /// This function iterates through all the `RegexPatternTable` instances in `regex_pattern_table_list`
    /// and checks if the provided text matches any of the regex patterns based on the `RegexType` of each table.
    ///
    /// # Arguments
    ///
    /// * `self` - A reference to the [RegexMatcher] instance.
    /// * `text` - A string slice (`&str`) containing the text to be checked for matches against the regex patterns.
    ///
    /// # Returns
    ///
    /// * `bool` - Returns `true` if the text matches any of the regex patterns, otherwise returns `false`.
    ///
    /// # Match Checking
    ///
    /// The function handles different `RegexType` variants within the `RegexPatternTable`:
    ///
    /// * `StandardRegex` - Checks if the text matches the single compiled regex pattern stored in the table.
    ///   If a match is found, the function returns `true`.
    ///
    /// * `ListRegex` - Iterates through the list of compiled regex patterns and checks if the text matches
    ///   any of them. If a match is found, the function returns `true`.
    ///
    /// If no matches are found after checking all regex patterns in all tables, the function returns `false`.
    ///
    /// # Examples
    ///
    /// ```
    /// use matcher_rs::{RegexMatcher, RegexTable, RegexMatchType, TextMatcherTrait};
    ///
    /// let regex_table = RegexTable {
    ///     table_id: 1,
    ///     match_id: 1,
    ///     regex_match_type: RegexMatchType::SimilarChar,
    ///     word_list: &vec!["1,一", "2,二"],
    /// };
    ///
    /// let regex_matcher = RegexMatcher::new(&vec![regex_table]);
    ///
    /// assert!(regex_matcher.is_match("12"));
    /// assert!(regex_matcher.is_match("一2"));
    /// assert!(regex_matcher.is_match("1二"));
    /// ```
    fn is_match(&self, text: &str) -> bool {
        for regex_table in &self.regex_pattern_table_list {
            match &regex_table.regex_type {
                RegexType::StandardRegex { regex } => {
                    if regex.is_match(text).unwrap() {
                        return true;
                    }
                }
                RegexType::ListRegex { regex_list, .. } => {
                    if regex_list.iter().any(|regex| regex.is_match(text).unwrap()) {
                        return true;
                    }
                }
            }
        }

        false
    }

    /// Processes the given text and returns a list of `RegexResult` instances for matches found.
    ///
    /// This function iterates through all the regex tables stored in `regex_pattern_table_list` and checks
    /// the provided text against the regex patterns based on the `RegexType` of each table. If a match is found,
    /// a corresponding `RegexResult` instance is created and added to the result list.
    ///
    /// # Arguments
    ///
    /// * `self` - A reference to the [RegexMatcher] instance.
    /// * `text` - A string slice (`&str`) containing the text to be processed and searched for matches.
    ///
    /// # Returns
    ///
    /// * [Vec<RegexResult<'a>>] - A vector of `RegexResult` instances, each representing a match found in the text.
    ///
    /// # Match Processing
    ///
    /// The function handles different `RegexType` variants within the `RegexPatternTable`:
    ///
    /// * `StandardRegex` - For each match found, the captured groups (except the full match) are concatenated
    ///   to form the matched word, which is stored in a `RegexResult` instance.
    ///
    /// * `ListRegex` - If the text matches any regex pattern in the list, the corresponding word from `word_list`
    ///   is stored in a `RegexResult` instance.
    ///
    /// # Examples
    ///
    /// ```
    /// use matcher_rs::{RegexMatcher, RegexTable, RegexMatchType, TextMatcherTrait};
    /// use std::borrow::Cow;
    ///
    /// let regex_table = RegexTable {
    ///     table_id: 1,
    ///     match_id: 1,
    ///     regex_match_type: RegexMatchType::SimilarChar,
    ///     word_list: &vec!["1,一", "2,二"],
    /// };
    ///
    /// let regex_matcher = RegexMatcher::new(&vec![regex_table]);
    ///
    /// let results = regex_matcher.process("12");
    /// for result in results {
    ///     println!("Matched word: {}", result.word);
    ///     println!("Table ID: {}", result.table_id);
    ///     println!("Match ID: {}", result.match_id);
    /// }
    /// ```
    fn process(&'a self, text: &str) -> Vec<RegexResult<'a>> {
        let mut result_list = Vec::new();

        for regex_table in &self.regex_pattern_table_list {
            match &regex_table.regex_type {
                RegexType::StandardRegex { regex } => {
                    for caps in regex.captures_iter(text).map(|caps| caps.unwrap()) {
                        result_list.push(RegexResult {
                            word: Cow::Owned(
                                caps.iter()
                                    .skip(1)
                                    .filter_map(|m| m.map(|match_char| match_char.as_str()))
                                    .collect::<Vec<&str>>()
                                    .join(""),
                            ),
                            table_id: regex_table.table_id,
                            match_id: regex_table.match_id,
                        });
                    }
                }
                RegexType::ListRegex {
                    regex_list,
                    word_list,
                } => {
                    for (index, regex) in regex_list.iter().enumerate() {
                        if regex.is_match(text).unwrap() {
                            result_list.push(RegexResult {
                                word: Cow::Borrowed(&word_list[index]),
                                table_id: regex_table.table_id,
                                match_id: regex_table.match_id,
                            });
                        }
                    }
                }
            }
        }

        result_list
    }
}
