jira-core 0.1.0

use std::time::Duration;

use reqwest::{
    header::{HeaderMap, HeaderValue, AUTHORIZATION, CONTENT_TYPE},
    Client, Response, StatusCode,
};
use serde_json::{json, Value};
use tracing::{debug, warn};

use crate::{
    adf::markdown_to_adf,
    config::JiraConfig,
    error::{JiraError, Result},
    model::{
        attachment::Attachment,
        field::Field,
        issue::{
            CreateIssueRequest, CreateIssueRequestV2, Issue, RawIssue, RawSearchResponse,
            SearchResult, UpdateIssueRequest,
        },
    },
};

const PLATFORM_BASE: &str = "/rest/api/3";
const AGILE_BASE: &str = "/rest/agile/1.0";
const MAX_RETRIES: u32 = 3;

pub struct JiraClient {
    http: Client,
    config: JiraConfig,
}

impl JiraClient {
    pub fn new(config: JiraConfig) -> Self {
        let http = Client::builder()
            .timeout(Duration::from_secs(config.timeout_secs))
            .build()
            .expect("Failed to build HTTP client");

        Self { http, config }
    }

    fn platform_url(&self, path: &str) -> String {
        format!(
            "{}{}{}",
            self.config.base_url.trim_end_matches('/'),
            PLATFORM_BASE,
            path
        )
    }

    #[allow(dead_code)]
    fn agile_url(&self, path: &str) -> String {
        format!(
            "{}{}{}",
            self.config.base_url.trim_end_matches('/'),
            AGILE_BASE,
            path
        )
    }

    fn auth_headers(&self) -> Result<HeaderMap> {
        let token = self.config.token.as_deref().ok_or_else(|| {
            JiraError::Auth("No token configured. Run `jira auth login` first.".into())
        })?;

        let credentials = base64_encode(&format!("{}:{}", self.config.email, token));
        let auth_value = format!("Basic {credentials}");

        let mut headers = HeaderMap::new();
        headers.insert(
            AUTHORIZATION,
            HeaderValue::from_str(&auth_value)
                .map_err(|e| JiraError::Auth(format!("Invalid auth header: {e}")))?,
        );
        headers.insert(CONTENT_TYPE, HeaderValue::from_static("application/json"));

        Ok(headers)
    }

    /// Auth headers without Content-Type — required for multipart uploads.
    fn auth_headers_no_content_type(&self) -> Result<HeaderMap> {
        let token = self.config.token.as_deref().ok_or_else(|| {
            JiraError::Auth("No token configured. Run `jira auth login` first.".into())
        })?;

        let credentials = base64_encode(&format!("{}:{}", self.config.email, token));
        let auth_value = format!("Basic {credentials}");

        let mut headers = HeaderMap::new();
        headers.insert(
            AUTHORIZATION,
            HeaderValue::from_str(&auth_value)
                .map_err(|e| JiraError::Auth(format!("Invalid auth header: {e}")))?,
        );
        Ok(headers)
    }

    /// Core request method with rate-limit retry logic.
    async fn request<T>(&self, builder_fn: impl Fn() -> reqwest::RequestBuilder) -> Result<T>
    where
        T: serde::de::DeserializeOwned,
    {
        let mut attempt = 0u32;
        loop {
            attempt += 1;
            let req = builder_fn();
            let response = req.send().await?;

            if response.status() == StatusCode::TOO_MANY_REQUESTS {
                let retry_after = response
                    .headers()
                    .get("Retry-After")
                    .and_then(|v| v.to_str().ok())
                    .and_then(|v| v.parse::<u64>().ok())
                    .unwrap_or(60);

                warn!("Rate limited. Retrying after {}s", retry_after);

                if attempt >= MAX_RETRIES {
                    return Err(JiraError::RateLimit { retry_after });
                }

                tokio::time::sleep(Duration::from_secs(retry_after)).await;
                continue;
            }

            return handle_response(response).await;
        }
    }

    /// Core request method for responses with no body (204 No Content).
    async fn request_no_body(
        &self,
        builder_fn: impl Fn() -> reqwest::RequestBuilder,
    ) -> Result<()> {
        let mut attempt = 0u32;
        loop {
            attempt += 1;
            let req = builder_fn();
            let response = req.send().await?;

            if response.status() == StatusCode::TOO_MANY_REQUESTS {
                let retry_after = response
                    .headers()
                    .get("Retry-After")
                    .and_then(|v| v.to_str().ok())
                    .and_then(|v| v.parse::<u64>().ok())
                    .unwrap_or(60);

                warn!("Rate limited. Retrying after {}s", retry_after);

                if attempt >= MAX_RETRIES {
                    return Err(JiraError::RateLimit { retry_after });
                }

                tokio::time::sleep(Duration::from_secs(retry_after)).await;
                continue;
            }

            let status = response.status();
            if status.is_success() {
                return Ok(());
            }

            let body = response.text().await.unwrap_or_default();
            if status == StatusCode::NOT_FOUND {
                return Err(JiraError::NotFound(body));
            }
            return Err(JiraError::Api {
                status: status.as_u16(),
                message: body,
            });
        }
    }

    /// Multipart request with rate-limit retry (for attachment uploads).
    async fn request_multipart<T>(
        &self,
        builder_fn: impl Fn() -> reqwest::RequestBuilder,
    ) -> Result<T>
    where
        T: serde::de::DeserializeOwned,
    {
        let mut attempt = 0u32;
        loop {
            attempt += 1;
            let req = builder_fn();
            let response = req.send().await?;

            if response.status() == StatusCode::TOO_MANY_REQUESTS {
                let retry_after = response
                    .headers()
                    .get("Retry-After")
                    .and_then(|v| v.to_str().ok())
                    .and_then(|v| v.parse::<u64>().ok())
                    .unwrap_or(60);

                warn!("Rate limited. Retrying after {}s", retry_after);

                if attempt >= MAX_RETRIES {
                    return Err(JiraError::RateLimit { retry_after });
                }

                tokio::time::sleep(Duration::from_secs(retry_after)).await;
                continue;
            }

            return handle_response(response).await;
        }
    }

    /// Search issues using JQL with cursor-based pagination.
    pub async fn search_issues(
        &self,
        jql: &str,
        next_page_token: Option<&str>,
        max_results: Option<u32>,
    ) -> Result<SearchResult> {
        let headers = self.auth_headers()?;
        let url = self.platform_url("/search/jql");

        let mut body = json!({
            "jql": jql,
            "maxResults": max_results.unwrap_or(50),
            "fields": ["summary", "status", "assignee", "reporter", "priority",
                       "issuetype", "project", "created", "updated", "description"]
        });

        if let Some(token) = next_page_token {
            body["nextPageToken"] = json!(token);
        }

        debug!("Searching JQL: {}", jql);

        let http = &self.http;
        let raw: RawSearchResponse = self
            .request(|| http.post(&url).headers(headers.clone()).json(&body))
            .await?;

        Ok(SearchResult {
            issues: raw.issues.into_iter().map(|r| r.into_issue()).collect(),
            next_page_token: raw.next_page_token,
            total: raw.total,
        })
    }

    /// Fetch a single issue by key.
    pub async fn get_issue(&self, key: &str) -> Result<Issue> {
        let headers = self.auth_headers()?;
        let url = self.platform_url(&format!("/issue/{key}"));

        let http = &self.http;
        let raw: RawIssue = self
            .request(|| http.get(&url).headers(headers.clone()))
            .await?;

        Ok(raw.into_issue())
    }

    /// Create a new issue.
    pub async fn create_issue(&self, req: CreateIssueRequest) -> Result<Issue> {
        let headers = self.auth_headers()?;
        let url = self.platform_url("/issue");

        let description_adf = req.description.as_deref().map(markdown_to_adf);

        let mut fields = json!({
            "project": { "key": req.project_key },
            "summary": req.summary,
            "issuetype": { "name": req.issue_type }
        });

        if let Some(adf) = description_adf {
            fields["description"] = adf;
        }

        if let Some(assignee) = &req.assignee {
            fields["assignee"] = json!({ "emailAddress": assignee });
        }

        if let Some(priority) = &req.priority {
            fields["priority"] = json!({ "name": priority });
        }

        let body = json!({ "fields": fields });

        #[derive(serde::Deserialize)]
        struct CreateResponse {
            key: String,
        }

        let http = &self.http;
        let resp: CreateResponse = self
            .request(|| http.post(&url).headers(headers.clone()).json(&body))
            .await?;

        // Fetch the full issue after creation
        self.get_issue(&resp.key).await
    }

    /// Update an existing issue.
    pub async fn update_issue(&self, key: &str, req: UpdateIssueRequest) -> Result<()> {
        let headers = self.auth_headers()?;
        let url = self.platform_url(&format!("/issue/{key}"));

        let mut fields = json!({});

        if let Some(summary) = &req.summary {
            fields["summary"] = json!(summary);
        }

        if let Some(description) = &req.description {
            fields["description"] = markdown_to_adf(description);
        }

        if let Some(assignee) = &req.assignee {
            fields["assignee"] = json!({ "emailAddress": assignee });
        }

        if let Some(priority) = &req.priority {
            fields["priority"] = json!({ "name": priority });
        }

        let body = json!({ "fields": fields });

        let http = &self.http;
        self.request_no_body(|| http.put(&url).headers(headers.clone()).json(&body))
            .await
    }

    /// Delete an issue.
    pub async fn delete_issue(&self, key: &str) -> Result<()> {
        let headers = self.auth_headers()?;
        let url = self.platform_url(&format!("/issue/{key}"));

        let http = &self.http;
        self.request_no_body(|| http.delete(&url).headers(headers.clone()))
            .await
    }

    /// Get fields available for a project (runtime field resolution — no hardcoding).
    pub async fn get_project_fields(&self, project_key: &str) -> Result<Vec<Field>> {
        let headers = self.auth_headers()?;
        let url = self.platform_url(&format!("/issue/createmeta/{project_key}/issuetypes"));

        #[derive(serde::Deserialize)]
        struct IssueTypeMeta {
            #[serde(rename = "issueTypes")]
            issue_types: Vec<IssueTypeDetail>,
        }

        #[derive(serde::Deserialize)]
        struct IssueTypeDetail {
            fields: Option<std::collections::HashMap<String, FieldMeta>>,
        }

        #[derive(serde::Deserialize)]
        struct FieldMeta {
            name: String,
            required: bool,
            schema: Option<Value>,
        }

        let http = &self.http;
        let meta: IssueTypeMeta = self
            .request(|| http.get(&url).headers(headers.clone()))
            .await?;

        let mut fields: Vec<Field> = Vec::new();
        let mut seen = std::collections::HashSet::new();

        for it in meta.issue_types {
            if let Some(field_map) = it.fields {
                for (id, meta) in field_map {
                    if seen.insert(id.clone()) {
                        let field_type = meta
                            .schema
                            .as_ref()
                            .and_then(|s| s.get("type"))
                            .and_then(|v| v.as_str())
                            .unwrap_or("unknown")
                            .to_string();

                        fields.push(Field {
                            id,
                            name: meta.name,
                            field_type,
                            required: meta.required,
                            schema: meta.schema,
                            allowed_values: None,
                        });
                    }
                }
            }
        }

        Ok(fields)
    }

    /// Get server info (used to detect Jira tier).
    pub async fn get_server_info(&self) -> Result<Value> {
        let headers = self.auth_headers()?;
        let url = self.platform_url("/serverInfo");

        let http = &self.http;
        self.request(|| http.get(&url).headers(headers.clone()))
            .await
    }

    /// Transition an issue to a new status.
    pub async fn transition_issue(&self, key: &str, transition_id: &str) -> Result<()> {
        let headers = self.auth_headers()?;
        let url = self.platform_url(&format!("/issue/{key}/transitions"));

        let body = json!({
            "transition": { "id": transition_id }
        });

        let http = &self.http;
        self.request_no_body(|| http.post(&url).headers(headers.clone()).json(&body))
            .await
    }

    /// Get available transitions for an issue.
    pub async fn get_transitions(&self, key: &str) -> Result<Vec<Value>> {
        let headers = self.auth_headers()?;
        let url = self.platform_url(&format!("/issue/{key}/transitions"));

        #[derive(serde::Deserialize)]
        struct TransitionsResponse {
            transitions: Vec<Value>,
        }

        let http = &self.http;
        let resp: TransitionsResponse = self
            .request(|| http.get(&url).headers(headers.clone()))
            .await?;

        Ok(resp.transitions)
    }

    /// Get available issue types for a project (id + name).
    pub async fn get_issue_types(&self, project_key: &str) -> Result<Vec<IssueType>> {
        let headers = self.auth_headers()?;
        let url = self.platform_url(&format!("/issue/createmeta/{project_key}/issuetypes"));

        #[derive(serde::Deserialize)]
        struct MetaResponse {
            #[serde(rename = "issueTypes")]
            issue_types: Vec<IssueType>,
        }

        let http = &self.http;
        let resp: MetaResponse = self
            .request(|| http.get(&url).headers(headers.clone()))
            .await?;

        Ok(resp.issue_types)
    }

    /// Get fields for a specific issue type within a project (with allowed values).
    pub async fn get_fields_for_issue_type(
        &self,
        project_key: &str,
        issue_type_id: &str,
    ) -> Result<Vec<Field>> {
        let headers = self.auth_headers()?;
        let url = self.platform_url(&format!(
            "/issue/createmeta/{project_key}/issuetypes/{issue_type_id}"
        ));

        #[derive(serde::Deserialize)]
        struct FieldMetaResponse {
            fields: std::collections::HashMap<String, FieldMeta>,
        }

        #[derive(serde::Deserialize)]
        struct FieldMeta {
            name: String,
            required: bool,
            schema: Option<Value>,
            #[serde(rename = "allowedValues")]
            allowed_values: Option<Vec<Value>>,
        }

        let http = &self.http;
        let resp: FieldMetaResponse = self
            .request(|| http.get(&url).headers(headers.clone()))
            .await?;

        let fields = resp
            .fields
            .into_iter()
            .map(|(id, meta)| {
                let field_type = meta
                    .schema
                    .as_ref()
                    .and_then(|s| s.get("type"))
                    .and_then(|v| v.as_str())
                    .unwrap_or("unknown")
                    .to_string();

                Field {
                    id,
                    name: meta.name,
                    field_type,
                    required: meta.required,
                    schema: meta.schema,
                    allowed_values: meta.allowed_values,
                }
            })
            .collect();

        Ok(fields)
    }

    /// Search Jira users by query string (for User field autocomplete).
    pub async fn search_users(&self, query: &str) -> Result<Vec<Value>> {
        let headers = self.auth_headers()?;
        let url = self.platform_url("/user/search");

        let http = &self.http;
        let users: Vec<Value> = self
            .request(|| {
                http.get(&url)
                    .headers(headers.clone())
                    .query(&[("query", query), ("maxResults", "20")])
            })
            .await?;

        Ok(users)
    }

    /// Upload a file as an attachment to an issue.
    pub async fn upload_attachment(
        &self,
        issue_key: &str,
        file_path: &std::path::Path,
    ) -> Result<Vec<Attachment>> {
        use reqwest::{header::HeaderValue, multipart};

        let headers = self.auth_headers_no_content_type()?;
        let url = self.platform_url(&format!("/issue/{issue_key}/attachments"));

        let file_name = file_path
            .file_name()
            .and_then(|n| n.to_str())
            .unwrap_or("attachment")
            .to_string();

        let bytes = std::fs::read(file_path)?;

        let mime = mime_guess::from_path(file_path)
            .first_or_octet_stream()
            .to_string();

        let http = &self.http;
        let raw_attachments: Vec<Value> = self
            .request_multipart(|| {
                let part = multipart::Part::bytes(bytes.clone())
                    .file_name(file_name.clone())
                    .mime_str(&mime)
                    .expect("invalid mime type");
                let form = multipart::Form::new().part("file", part);

                let mut req_headers = headers.clone();
                req_headers.insert("X-Atlassian-Token", HeaderValue::from_static("no-check"));

                http.post(&url).headers(req_headers).multipart(form)
            })
            .await?;

        Ok(raw_attachments
            .iter()
            .filter_map(Attachment::from_value)
            .collect())
    }

    /// Create a new issue with dynamic custom fields.
    pub async fn create_issue_v2(&self, req: CreateIssueRequestV2) -> Result<Issue> {
        let headers = self.auth_headers()?;
        let url = self.platform_url("/issue");

        let description_adf = req.description.as_deref().map(markdown_to_adf);

        let mut fields = json!({
            "project": { "key": req.project_key },
            "summary": req.summary,
            "issuetype": { "name": req.issue_type }
        });

        if let Some(adf) = description_adf {
            fields["description"] = adf;
        }
        if let Some(assignee) = &req.assignee {
            fields["assignee"] = json!({ "emailAddress": assignee });
        }
        if let Some(priority) = &req.priority {
            fields["priority"] = json!({ "name": priority });
        }

        for (field_id, value) in &req.custom_fields {
            fields[field_id] = value.to_api_json();
        }

        let body = json!({ "fields": fields });

        #[derive(serde::Deserialize)]
        struct CreateResponse {
            key: String,
        }

        let http = &self.http;
        let resp: CreateResponse = self
            .request(|| http.post(&url).headers(headers.clone()).json(&body))
            .await?;

        self.get_issue(&resp.key).await
    }
}

/// Issue type metadata (id + name) returned by createmeta.
#[derive(Debug, Clone, serde::Deserialize, serde::Serialize)]
pub struct IssueType {
    pub id: String,
    pub name: String,
}

async fn handle_response<T>(response: Response) -> Result<T>
where
    T: serde::de::DeserializeOwned,
{
    let status = response.status();

    if status.is_success() {
        let value: T = response.json().await?;
        return Ok(value);
    }

    let body = response.text().await.unwrap_or_default();

    match status {
        StatusCode::NOT_FOUND => Err(JiraError::NotFound(body)),
        StatusCode::UNAUTHORIZED | StatusCode::FORBIDDEN => {
            Err(JiraError::Auth(format!("HTTP {status}: {body}")))
        }
        _ => Err(JiraError::Api {
            status: status.as_u16(),
            message: body,
        }),
    }
}

fn base64_encode(input: &str) -> String {
    use std::fmt::Write;
    const CHARS: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    let bytes = input.as_bytes();
    let mut result = String::new();
    let mut i = 0;
    while i < bytes.len() {
        let b0 = bytes[i] as u32;
        let b1 = if i + 1 < bytes.len() {
            bytes[i + 1] as u32
        } else {
            0
        };
        let b2 = if i + 2 < bytes.len() {
            bytes[i + 2] as u32
        } else {
            0
        };

        let _ = write!(result, "{}", CHARS[((b0 >> 2) & 0x3F) as usize] as char);
        let _ = write!(
            result,
            "{}",
            CHARS[(((b0 & 0x3) << 4) | ((b1 >> 4) & 0xF)) as usize] as char
        );
        if i + 1 < bytes.len() {
            let _ = write!(
                result,
                "{}",
                CHARS[(((b1 & 0xF) << 2) | ((b2 >> 6) & 0x3)) as usize] as char
            );
        } else {
            result.push('=');
        }
        if i + 2 < bytes.len() {
            let _ = write!(result, "{}", CHARS[(b2 & 0x3F) as usize] as char);
        } else {
            result.push('=');
        }
        i += 3;
    }
    result
}