// MinIO Rust Library for Amazon S3 Compatible Cloud Storage
// Copyright 2022 MinIO, Inc.
//
// 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.

//! HTTP URL definitions

use super::utils::urlencode_object_key;
use crate::s3::client::DEFAULT_REGION;
use crate::s3::error::Error;
use crate::s3::utils::match_hostname;
use crate::s3::utils::{Multimap, to_query_string};
use derivative::Derivative;
use hyper::Uri;
use hyper::http::Method;
use lazy_static::lazy_static;
use regex::Regex;
use std::fmt;
use std::str::FromStr;

const AWS_S3_PREFIX: &str = r"^(((bucket\.|accesspoint\.)vpce(-[a-z_\d]+)+\.s3\.)|([a-z_\d-]{1,63}\.)s3-control(-[a-z_\d]+)*\.|(s3(-[a-z_\d]+)*\.))";

lazy_static! {
    static ref AWS_ELB_ENDPOINT_REGEX: Regex =
        Regex::new(r"^[a-z_\d-]{1,63}\.[a-z_\d-]{1,63}\.elb\.amazonaws\.com$").unwrap();
    static ref AWS_S3_PREFIX_REGEX: Regex = Regex::new(AWS_S3_PREFIX).unwrap();
}

#[derive(Derivative)]
#[derivative(Clone, Debug, Default)]
/// Represents HTTP URL
pub struct Url {
    #[derivative(Default(value = "true"))]
    pub https: bool,
    pub host: String,
    pub port: u16,
    pub path: String,
    pub query: Multimap,
}

impl Url {
    pub fn host_header_value(&self) -> String {
        if self.port > 0 {
            return format!("{}:{}", self.host, self.port);
        }
        self.host.clone()
    }
}

impl fmt::Display for Url {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        if self.host.is_empty() {
            return Err(std::fmt::Error);
        }

        if self.https {
            f.write_str("https://")?;
        } else {
            f.write_str("http://")?;
        }

        if self.port > 0 {
            f.write_str(format!("{}:{}", self.host, self.port).as_str())?;
        } else {
            f.write_str(&self.host)?;
        }

        if !self.path.starts_with('/') {
            f.write_str("/")?;
        }
        f.write_str(&self.path)?;

        if !self.query.is_empty() {
            f.write_str("?")?;
            f.write_str(&to_query_string(&self.query))?;
        }

        Ok(())
    }
}

pub fn match_aws_endpoint(value: &str) -> bool {
    lazy_static! {
        static ref AWS_ENDPOINT_REGEX: Regex = Regex::new(r".*\.amazonaws\.com(|\.cn)$").unwrap();
    }

    AWS_ENDPOINT_REGEX.is_match(value.to_lowercase().as_str())
}

pub fn match_aws_s3_endpoint(value: &str) -> bool {
    lazy_static! {
        static ref AWS_S3_ENDPOINT_REGEX: Regex = Regex::new(
            &(AWS_S3_PREFIX.to_string() + r"([a-z_\d-]{1,63}\.)*amazonaws\.com(|\.cn)$")
        )
        .unwrap();
    }

    let binding = value.to_lowercase();
    let lvalue = binding.as_str();

    if !AWS_S3_ENDPOINT_REGEX.is_match(lvalue) {
        return false;
    }

    for token in lvalue.split('.') {
        if token.starts_with('-')
            || token.starts_with('_')
            || token.ends_with('-')
            || token.ends_with('_')
            || token.starts_with("vpce-_")
            || token.starts_with("s3-control-_")
            || token.starts_with("s3-_")
        {
            return false;
        }
    }

    true
}

fn get_aws_info(
    host: &String,
    https: bool,
    region: &mut String,
    aws_s3_prefix: &mut String,
    aws_domain_suffix: &mut String,
    dualstack: &mut bool,
) -> Result<(), Error> {
    if !match_hostname(host.as_str()) {
        return Ok(());
    }

    if AWS_ELB_ENDPOINT_REGEX.is_match(host.as_str()) {
        let token = host
            .get(..host.rfind(".elb.amazonaws.com").unwrap() - 1)
            .unwrap();
        *region = token
            .get(token.rfind('.').unwrap() + 1..)
            .unwrap()
            .to_string();
        return Ok(());
    }

    if !match_aws_endpoint(host.as_str()) {
        return Ok(());
    }

    if !match_aws_s3_endpoint(host.as_str()) {
        return Err(Error::UrlBuildError(
            String::from("invalid Amazon AWS host ") + host,
        ));
    }

    let matcher = AWS_S3_PREFIX_REGEX.find(host.as_str()).unwrap();
    let s3_prefix = host.get(..matcher.end()).unwrap();

    if s3_prefix.contains("s3-accesspoint") && !https {
        return Err(Error::UrlBuildError(
            String::from("use HTTPS scheme for host ") + host,
        ));
    }

    let mut tokens: Vec<_> = host.get(matcher.len()..).unwrap().split('.').collect();
    *dualstack = tokens[0] == "dualstack";
    if *dualstack {
        tokens.remove(0);
    }

    let mut region_in_host = String::new();
    if tokens[0] != "vpce" && tokens[0] != "amazonaws" {
        region_in_host = tokens[0].to_string();
        tokens.remove(0);
    }

    let domain_suffix = tokens.join(".");

    if host == "s3-external-1.amazonaws.com" {
        region_in_host = DEFAULT_REGION.to_string();
    }
    if host == "s3-us-gov-west-1.amazonaws.com" || host == "s3-fips-us-gov-west-1.amazonaws.com" {
        region_in_host = "us-gov-west-1".to_string();
    }

    if domain_suffix.ends_with(".cn") && !s3_prefix.ends_with("s3-accelerate.") && region.is_empty()
    {
        return Err(Error::UrlBuildError(
            String::from("region missing in Amazon S3 China endpoint ") + host,
        ));
    }

    *region = region_in_host;
    *aws_s3_prefix = s3_prefix.to_string();
    *aws_domain_suffix = domain_suffix;

    Ok(())
}

#[derive(Derivative)]
#[derivative(Clone, Debug, Default)]
/// Represents Base URL of S3 endpoint
pub struct BaseUrl {
    #[derivative(Default(value = "true"))]
    pub https: bool,
    host: String,
    port: u16,
    pub region: String,
    aws_s3_prefix: String,
    aws_domain_suffix: String,
    pub dualstack: bool,
    pub virtual_style: bool,
}

impl FromStr for BaseUrl {
    type Err = Error;

    /// Convert a string to a BaseUrl.
    ///
    /// Enables use of [`str::parse`] method to create a [`BaseUrl`].
    ///
    /// # Examples
    ///
    /// ```
    /// use minio::s3::http::BaseUrl;
    /// use std::str::FromStr;
    ///
    /// // Get base URL from host name
    /// let base_url = "play.min.io".parse::<BaseUrl>().unwrap();
    /// let base_url = BaseUrl::from_str("play.min.io").unwrap();
    /// // Get base URL from host:port
    /// let base_url: BaseUrl = "play.minio.io:9000".parse().unwrap();
    /// // Get base URL from IPv4 address
    /// let base_url: BaseUrl = "http://192.168.124.63:9000".parse().unwrap();
    /// // Get base URL from IPv6 address
    /// let base_url: BaseUrl = "[0:0:0:0:0:ffff:c0a8:7c3f]:9000".parse().unwrap();
    /// ```
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let url = s.parse::<Uri>()?;

        let https = match url.scheme() {
            None => true,
            Some(scheme) => match scheme.as_str() {
                "http" => false,
                "https" => true,
                _ => {
                    return Err(Error::InvalidBaseUrl(String::from(
                        "scheme must be http or https",
                    )));
                }
            },
        };

        let mut host = match url.host() {
            Some(h) => h,
            _ => {
                return Err(Error::InvalidBaseUrl(String::from(
                    "valid host must be provided",
                )));
            }
        };

        let ipv6host = "[".to_string() + host + "]";
        if host.parse::<std::net::Ipv6Addr>().is_ok() {
            host = &ipv6host;
        }

        let mut port = match url.port() {
            Some(p) => p.as_u16(),
            _ => 0u16,
        };

        if (https && port == 443) || (!https && port == 80) {
            port = 0u16;
        }

        if url.path() != "/" && url.path() != "" {
            return Err(Error::InvalidBaseUrl(String::from(
                "path must be empty for base URL",
            )));
        }

        if url.query().is_some() {
            return Err(Error::InvalidBaseUrl(String::from(
                "query must be none for base URL",
            )));
        }

        let mut region = String::new();
        let mut aws_s3_prefix = String::new();
        let mut aws_domain_suffix = String::new();
        let mut dualstack: bool = false;
        get_aws_info(
            &host.to_string(),
            https,
            &mut region,
            &mut aws_s3_prefix,
            &mut aws_domain_suffix,
            &mut dualstack,
        )?;
        let virtual_style = !aws_domain_suffix.is_empty() || host.ends_with("aliyuncs.com");

        Ok(BaseUrl {
            https,
            host: host.to_string(),
            port,
            region,
            aws_s3_prefix,
            aws_domain_suffix,
            dualstack,
            virtual_style,
        })
    }
}

impl BaseUrl {
    /// Checks base URL is AWS host
    pub fn is_aws_host(&self) -> bool {
        !self.aws_domain_suffix.is_empty()
    }

    fn build_aws_url(
        &self,
        url: &mut Url,
        bucket_name: &str,
        enforce_path_style: bool,
        region: &str,
    ) -> Result<(), Error> {
        let mut host = String::from(&self.aws_s3_prefix);
        host.push_str(&self.aws_domain_suffix);
        if host == "s3-external-1.amazonaws.com"
            || host == "s3-us-gov-west-1.amazonaws.com"
            || host == "s3-fips-us-gov-west-1.amazonaws.com"
        {
            url.host = host;
            return Ok(());
        }

        host = String::from(&self.aws_s3_prefix);
        if self.aws_s3_prefix.contains("s3-accelerate") {
            if bucket_name.contains('.') {
                return Err(Error::UrlBuildError(String::from(
                    "bucket name with '.' is not allowed for accelerate endpoint",
                )));
            }

            if enforce_path_style {
                host = host.replacen("-accelerate", "", 1);
            }
        }

        if self.dualstack {
            host.push_str("dualstack.");
        }
        if !self.aws_s3_prefix.contains("s3-accelerate") {
            host.push_str(region);
            host.push('.');
        }
        host.push_str(&self.aws_domain_suffix);

        url.host = host;

        Ok(())
    }

    fn build_list_buckets_url(&self, url: &mut Url, region: &str) {
        if self.aws_domain_suffix.is_empty() {
            return;
        }

        let mut host = String::from(&self.aws_s3_prefix);
        host.push_str(&self.aws_domain_suffix);
        if host == "s3-external-1.amazonaws.com"
            || host == "s3-us-gov-west-1.amazonaws.com"
            || host == "s3-fips-us-gov-west-1.amazonaws.com"
        {
            url.host = host;
            return;
        }

        let mut s3_prefix = String::from(&self.aws_s3_prefix);
        let mut domain_suffix = String::from(&self.aws_domain_suffix);
        if s3_prefix.starts_with("s3.") || s3_prefix.starts_with("s3-") {
            s3_prefix = "s3.".to_string();
            domain_suffix = "amazonaws.com".to_string();
            if self.aws_domain_suffix.ends_with(".cn") {
                domain_suffix.push_str(".cn");
            }
        }
        url.host = s3_prefix + region + "." + &domain_suffix;
    }

    /// Builds URL from base URL for given parameters for S3 operation
    pub fn build_url(
        &self,
        method: &Method,
        region: &str,
        query: &Multimap,
        bucket_name: Option<&str>,
        object_name: Option<&str>,
    ) -> Result<Url, Error> {
        if !object_name.is_none_or(|v| v.is_empty()) && bucket_name.is_none_or(|v| v.is_empty()) {
            return Err(Error::UrlBuildError(String::from(
                "empty bucket name provided for object name",
            )));
        }

        let mut url = Url {
            https: self.https,
            host: self.host.clone(),
            port: self.port,
            path: String::from("/"),
            query: query.clone(),
        };

        if bucket_name.is_none() {
            self.build_list_buckets_url(&mut url, region);
            return Ok(url);
        }

        let bucket = bucket_name.unwrap();

        #[allow(clippy::nonminimal_bool)]
        let enforce_path_style = true &&
	// CreateBucket API requires path style in Amazon AWS S3.
	    (method == Method::PUT && object_name.is_none() && query.is_empty()) ||
	// GetBucketLocation API requires path style in Amazon AWS S3.
	    query.contains_key("location") ||
	// Use path style for bucket name containing '.' which causes
	// SSL certificate validation error.
	    (bucket.contains('.') && self.https);

        if !self.aws_domain_suffix.is_empty() {
            self.build_aws_url(&mut url, bucket, enforce_path_style, region)?;
        }

        let mut host = String::from(&url.host);
        let mut path = String::new();

        if enforce_path_style || !self.virtual_style {
            path.push('/');
            path.push_str(bucket);
        } else {
            host = format!("{}.{}", bucket, url.host);
        }

        if let Some(v) = object_name {
            if !v.starts_with('/') {
                path.push('/');
            }
            path.push_str(&urlencode_object_key(v));
        }

        url.host = host;
        url.path = path;

        Ok(url)
    }
}