//! Official JP resource download execution.

use crate::official_pull::OfficialResourcePullPlan;
use bat_adapters::official::yostar_jp::is_official_yostar_jp_url;
use std::fs;
use std::path::{Path, PathBuf};
use std::process::Command;

/// One downloaded official resource.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct OfficialResourcePullItem {
    /// Original URL.
    pub url: String,
    /// Local destination path under the output root.
    pub destination: PathBuf,
    /// Downloaded byte count.
    pub bytes: u64,
}

/// Download report for one executed pull plan.
#[derive(Debug, Clone, Default, PartialEq, Eq)]
pub struct OfficialResourcePullReport {
    /// Downloaded resources in execution order.
    pub items: Vec<OfficialResourcePullItem>,
}

impl OfficialResourcePullReport {
    /// Returns the total downloaded byte count.
    pub fn total_bytes(&self) -> u64 {
        self.items.iter().map(|item| item.bytes).sum()
    }
}

/// Executes an official pull plan with the system `curl` command.
#[derive(Debug, Clone)]
pub struct OfficialResourcePullService {
    output_root: PathBuf,
    curl_command: PathBuf,
}

impl OfficialResourcePullService {
    /// Creates a pull service that uses `curl` from `PATH`.
    pub fn new(output_root: impl Into<PathBuf>) -> Self {
        Self::with_curl_command(output_root, "curl")
    }

    /// Creates a pull service with an explicit `curl` binary path.
    pub fn with_curl_command(
        output_root: impl Into<PathBuf>,
        curl_command: impl Into<PathBuf>,
    ) -> Self {
        Self {
            output_root: output_root.into(),
            curl_command: curl_command.into(),
        }
    }

    /// Returns the output root used for downloaded files.
    pub fn output_root(&self) -> &Path {
        &self.output_root
    }

    /// Executes the plan and downloads every official URL to disk.
    pub fn pull(
        &self,
        plan: &OfficialResourcePullPlan,
    ) -> Result<OfficialResourcePullReport, String> {
        fs::create_dir_all(&self.output_root).map_err(|error| {
            format!(
                "Failed to create output root {}: {error}",
                self.output_root.display()
            )
        })?;

        let mut items = Vec::new();
        for url in plan.all_urls()? {
            if !is_official_yostar_jp_url(&url) {
                return Err(format!("Refusing to download non-official URL: {url}"));
            }

            let destination = self.destination_for_url(&url)?;
            if let Some(parent) = destination.parent() {
                fs::create_dir_all(parent).map_err(|error| {
                    format!(
                        "Failed to create destination directory {}: {error}",
                        parent.display()
                    )
                })?;
            }

            self.download_one(&url, &destination)?;
            let bytes = fs::metadata(&destination)
                .map_err(|error| {
                    format!(
                        "Downloaded file missing at {}: {error}",
                        destination.display()
                    )
                })?
                .len();

            items.push(OfficialResourcePullItem {
                url,
                destination,
                bytes,
            });
        }

        Ok(OfficialResourcePullReport { items })
    }

    /// Fetches an official URL into memory.
    ///
    /// This is intended for small discovery inputs such as `server-info`,
    /// `TableCatalog.bytes`, `BundlePackingInfo.bytes`, and
    /// `MediaCatalog.bytes`.
    pub fn fetch_bytes(&self, url: &str) -> Result<Vec<u8>, String> {
        if !is_official_yostar_jp_url(url) {
            return Err(format!("Refusing to fetch non-official URL: {url}"));
        }

        let output = Command::new(&self.curl_command)
            .arg("--fail")
            .arg("--location")
            .arg("--silent")
            .arg("--show-error")
            .arg("--url")
            .arg(url)
            .output()
            .map_err(|error| {
                format!(
                    "Failed to launch curl command {}: {error}",
                    self.curl_command.display()
                )
            })?;

        if !output.status.success() {
            let stderr = String::from_utf8_lossy(&output.stderr);
            return Err(format!("curl failed for {url}: {}", stderr.trim()));
        }

        Ok(output.stdout)
    }

    fn download_one(&self, url: &str, destination: &Path) -> Result<(), String> {
        let output = Command::new(&self.curl_command)
            .arg("--fail")
            .arg("--location")
            .arg("--silent")
            .arg("--show-error")
            .arg("--output")
            .arg(destination)
            .arg("--url")
            .arg(url)
            .output()
            .map_err(|error| {
                format!(
                    "Failed to launch curl command {}: {error}",
                    self.curl_command.display()
                )
            })?;

        if !output.status.success() {
            let stderr = String::from_utf8_lossy(&output.stderr);
            return Err(format!(
                "curl failed for {url} -> {}: {}",
                destination.display(),
                stderr.trim()
            ));
        }

        Ok(())
    }

    fn destination_for_url(&self, url: &str) -> Result<PathBuf, String> {
        if !is_official_yostar_jp_url(url) {
            return Err(format!("URL is not an official JP host: {url}"));
        }

        let rest = url
            .strip_prefix("https://")
            .ok_or_else(|| format!("Official URL must use https: {url}"))?;
        let (host, path) = rest
            .split_once('/')
            .ok_or_else(|| format!("Official URL has no path: {url}"))?;

        let mut destination = PathBuf::from(sanitize_segment(host));
        for segment in path.split('/') {
            if segment.is_empty() {
                continue;
            }
            if segment == "." || segment == ".." {
                return Err(format!("Official URL has unsafe path segment: {url}"));
            }

            let segment = segment.split(['?', '#']).next().unwrap_or(segment);
            if segment.is_empty() {
                continue;
            }
            destination.push(sanitize_segment(segment));
        }

        Ok(self.output_root.join(destination))
    }
}

fn sanitize_segment(segment: &str) -> String {
    segment
        .chars()
        .map(|ch| {
            if matches!(ch, ':' | '*' | '?' | '"' | '<' | '>' | '|') {
                '_'
            } else {
                ch
            }
        })
        .collect()
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::official_pull::{
        build_official_pull_plan, build_official_pull_plan_for_platforms, OfficialResourcePullPlan,
    };
    use bat_adapters::official::inventory::{
        YostarJpDownloadInventory, YostarJpPlatformDownloadInventory,
    };
    use bat_adapters::official::yostar_jp::{
        PatchPlatform, YostarJpResourceDiscoveryPlan, YostarJpResourceEndpoint,
        YostarJpResourceEndpointKind,
    };
    use std::fs;
    use tempfile::TempDir;

    fn discovery_plan() -> YostarJpResourceDiscoveryPlan {
        YostarJpResourceDiscoveryPlan {
            connection_group_name: "Prod-Audit".to_string(),
            app_version: "1.70.0".to_string(),
            bundle_version: Some("s8tloc7lo3".to_string()),
            addressables_root:
                "https://prod-clientpatch.bluearchiveyostar.com/r93_token".to_string(),
            endpoints: vec![
                YostarJpResourceEndpoint {
                    kind: YostarJpResourceEndpointKind::TableCatalog,
                    platform: None,
                    url: "https://prod-clientpatch.bluearchiveyostar.com/r93_token/TableBundles/TableCatalog.bytes".to_string(),
                },
                YostarJpResourceEndpoint {
                    kind: YostarJpResourceEndpointKind::TableCatalogHash,
                    platform: None,
                    url: "https://prod-clientpatch.bluearchiveyostar.com/r93_token/TableBundles/TableCatalog.hash".to_string(),
                },
            ],
        }
    }

    fn inventory() -> YostarJpDownloadInventory {
        YostarJpDownloadInventory::from_catalog_bytes(
            b"FullPatch_000.zip",
            b"ExcelDB.db",
            b"JP_Airi.zip",
        )
    }

    fn platform_inventory() -> YostarJpPlatformDownloadInventory {
        YostarJpPlatformDownloadInventory::from_shared_inventory(
            inventory(),
            &[PatchPlatform::Windows],
        )
    }

    fn fake_curl_script() -> &'static str {
        r#"#!/bin/sh
set -eu
out=""
url=""
while [ "$#" -gt 0 ]; do
    case "$1" in
        --output)
            out="$2"
            shift 2
            ;;
        --url)
            url="$2"
            shift 2
            ;;
        *)
            shift
            ;;
    esac
done
if [ -n "$out" ]; then
    mkdir -p "$(dirname "$out")"
    printf '%s' "$url" > "$out"
else
    printf '%s' "$url"
fi
"#
    }

    fn write_fake_curl(path: &Path) {
        fs::write(path, fake_curl_script()).unwrap();
        #[cfg(unix)]
        {
            use std::os::unix::fs::PermissionsExt;
            let mut permissions = fs::metadata(path).unwrap().permissions();
            permissions.set_mode(0o755);
            fs::set_permissions(path, permissions).unwrap();
        }
    }

    #[test]
    fn downloads_verified_pull_plan_to_disk() {
        let out_dir = TempDir::new().unwrap();
        let bin_dir = TempDir::new().unwrap();
        let curl_path = bin_dir.path().join("curl");
        write_fake_curl(&curl_path);

        let service = OfficialResourcePullService::with_curl_command(out_dir.path(), &curl_path);
        let plan = build_official_pull_plan(discovery_plan(), inventory());
        let report = service.pull(&plan).unwrap();

        assert_eq!(report.items.len(), 7);
        assert!(report.total_bytes() > 0);
        assert_eq!(report.items[0].url, plan.discovery.endpoints[0].url);
        for item in &report.items {
            assert!(item.destination.exists());
            assert_eq!(fs::read_to_string(&item.destination).unwrap(), item.url);
        }
    }

    #[test]
    fn custom_platform_selection_is_supported() {
        let out_dir = TempDir::new().unwrap();
        let bin_dir = TempDir::new().unwrap();
        let curl_path = bin_dir.path().join("curl");
        write_fake_curl(&curl_path);

        let service = OfficialResourcePullService::with_curl_command(out_dir.path(), &curl_path);
        let plan = build_official_pull_plan_for_platforms(
            discovery_plan(),
            inventory(),
            &[PatchPlatform::Windows, PatchPlatform::Android],
        );
        let report = service.pull(&plan).unwrap();

        assert_eq!(report.items.len(), 7);
        assert!(report
            .items
            .iter()
            .any(|item| item.url.contains("Android_PatchPack")));
    }

    #[test]
    fn fetches_official_seed_bytes_with_curl() {
        let out_dir = TempDir::new().unwrap();
        let bin_dir = TempDir::new().unwrap();
        let curl_path = bin_dir.path().join("curl");
        write_fake_curl(&curl_path);

        let service = OfficialResourcePullService::with_curl_command(out_dir.path(), &curl_path);
        let bytes = service
            .fetch_bytes(
                "https://prod-clientpatch.bluearchiveyostar.com/r93_token/TableBundles/TableCatalog.bytes",
            )
            .unwrap();

        assert_eq!(
            String::from_utf8(bytes).unwrap(),
            "https://prod-clientpatch.bluearchiveyostar.com/r93_token/TableBundles/TableCatalog.bytes"
        );
    }

    #[test]
    fn rejects_non_official_urls() {
        let service = OfficialResourcePullService::new("/tmp/unused");
        let plan = OfficialResourcePullPlan {
            discovery: YostarJpResourceDiscoveryPlan {
                connection_group_name: "Prod-Audit".to_string(),
                app_version: "1.70.0".to_string(),
                bundle_version: None,
                addressables_root:
                    "https://prod-clientpatch.bluearchiveyostar.com/r93_token".to_string(),
                endpoints: vec![YostarJpResourceEndpoint {
                    kind: YostarJpResourceEndpointKind::TableCatalog,
                    platform: None,
                    url: "https://prod-clientpatch.bluearchive.cafe/r93_token/TableBundles/TableCatalog.bytes".to_string(),
                }],
            },
            inventory: platform_inventory(),
            platforms: vec![PatchPlatform::Windows],
        };

        assert!(service.pull(&plan).is_err());
    }
}