//! Reqwest-backed HTTP client + minimal wire DTOs.
//!
//! The CLI deliberately re-declares small request/response structs here
//! rather than depending on `manager-core` (and pulling its Postgres
//! transitive surface). Fields kept to what the CLI actually sends or
//! reads.

use std::collections::BTreeMap;

use anyhow::{anyhow, Context, Result};
use chrono::{DateTime, Utc};
use picloud_shared::{
    AdminUserId, ApiKeyId, App, AppId, AppRole, ExecutionLog, InstanceRole, Scope, Script,
};
use reqwest::{header, Method, RequestBuilder, StatusCode};
use serde::{Deserialize, Serialize};
use serde_json::Value;

use crate::config::Credentials;

pub struct Client {
    http: reqwest::Client,
    url: String,
    token: String,
}

impl Client {
    pub fn from_creds(creds: &Credentials) -> Result<Self> {
        Self::new(&creds.url, &creds.token)
    }

    pub fn new(url: &str, token: &str) -> Result<Self> {
        let http = reqwest::Client::builder()
            .user_agent(concat!("pic/", env!("CARGO_PKG_VERSION")))
            .build()
            .context("building HTTP client")?;
        Ok(Self {
            http,
            url: url.trim_end_matches('/').to_string(),
            token: token.to_string(),
        })
    }

    #[allow(dead_code)] // used by the trailing-slash unit test below.
    pub fn url(&self) -> &str {
        &self.url
    }

    fn request(&self, method: Method, path: &str) -> RequestBuilder {
        self.http
            .request(method, format!("{}{path}", self.url))
            .header(header::AUTHORIZATION, format!("Bearer {}", self.token))
    }

    /// `GET /api/v1/admin/auth/me`
    pub async fn auth_me(&self) -> Result<AuthMeDto> {
        let resp = self
            .request(Method::GET, "/api/v1/admin/auth/me")
            .send()
            .await?;
        decode(resp).await
    }

    /// `GET /api/v1/admin/apps`
    pub async fn apps_list(&self) -> Result<Vec<App>> {
        let resp = self
            .request(Method::GET, "/api/v1/admin/apps")
            .send()
            .await?;
        decode(resp).await
    }

    /// `GET /api/v1/admin/apps/{id_or_slug}` — slug or UUID accepted.
    pub async fn apps_get(&self, ident: &str) -> Result<AppLookupDto> {
        let resp = self
            .request(Method::GET, &format!("/api/v1/admin/apps/{ident}"))
            .send()
            .await?;
        decode(resp).await
    }

    /// `POST /api/v1/admin/apps`
    pub async fn apps_create(&self, body: &CreateAppBody<'_>) -> Result<App> {
        let resp = self
            .request(Method::POST, "/api/v1/admin/apps")
            .json(body)
            .send()
            .await?;
        decode(resp).await
    }

    /// `GET /api/v1/admin/scripts?app={ident}`
    pub async fn scripts_list_by_app(&self, ident: &str) -> Result<Vec<Script>> {
        let resp = self
            .request(
                Method::GET,
                &format!("/api/v1/admin/scripts?app={}", urlencoded(ident)),
            )
            .send()
            .await?;
        decode(resp).await
    }

    /// `GET /api/v1/admin/scripts` — every script the caller can see
    /// (server filters by membership for `Member`). Lets `pic scripts ls`
    /// (no `--app`) collapse what used to be an N+1 per-app walk into a
    /// single request that can't be partially-broken by a concurrent app
    /// delete.
    pub async fn scripts_list_all(&self) -> Result<Vec<Script>> {
        let resp = self
            .request(Method::GET, "/api/v1/admin/scripts")
            .send()
            .await?;
        decode(resp).await
    }

    /// `DELETE /api/v1/admin/apps/{id_or_slug}` with optional `?force=true`.
    /// Server requires `AppAdmin` capability; without `force`, returns
    /// 409 if the app still has scripts.
    pub async fn apps_delete(&self, ident: &str, force: bool) -> Result<()> {
        let path = if force {
            format!("/api/v1/admin/apps/{ident}?force=true")
        } else {
            format!("/api/v1/admin/apps/{ident}")
        };
        let resp = self.request(Method::DELETE, &path).send().await?;
        decode_status(resp).await
    }

    /// `DELETE /api/v1/admin/scripts/{id}` — requires `AppAdmin` on the
    /// owning app (stricter than the edit endpoints, by design).
    pub async fn scripts_delete(&self, id: &str) -> Result<()> {
        let resp = self
            .request(Method::DELETE, &format!("/api/v1/admin/scripts/{id}"))
            .send()
            .await?;
        decode_status(resp).await
    }

    /// `POST /api/v1/admin/scripts`
    pub async fn scripts_create(&self, body: &CreateScriptBody<'_>) -> Result<Script> {
        let resp = self
            .request(Method::POST, "/api/v1/admin/scripts")
            .json(body)
            .send()
            .await?;
        decode(resp).await
    }

    /// `PUT /api/v1/admin/scripts/{id}` — matches the dashboard, which
    /// uses PUT despite the field-level update semantics.
    pub async fn scripts_update_source(&self, id: &str, source: &str) -> Result<Script> {
        let body = UpdateScriptBody { source };
        let resp = self
            .request(Method::PUT, &format!("/api/v1/admin/scripts/{id}"))
            .json(&body)
            .send()
            .await?;
        decode(resp).await
    }

    /// `POST /api/v1/execute/{id}` — returns the raw HTTP status, headers,
    /// and JSON body (the orchestrator marshals the script's output as
    /// the HTTP response itself, not a wrapper object).
    pub async fn execute(
        &self,
        id: &str,
        body: Value,
        headers: &[(String, String)],
    ) -> Result<ExecuteResponse> {
        let mut req = self
            .request(Method::POST, &format!("/api/v1/execute/{id}"))
            .json(&body);
        for (k, v) in headers {
            req = req.header(k, v);
        }
        let resp = req.send().await?;
        let status = resp.status().as_u16();
        let mut headers_out: BTreeMap<String, String> = BTreeMap::new();
        for (k, v) in resp.headers() {
            if let Ok(val) = v.to_str() {
                headers_out.insert(k.as_str().to_string(), val.to_string());
            }
        }
        let bytes = resp.bytes().await.context("reading execute response")?;
        let body_json: Value = if bytes.is_empty() {
            Value::Null
        } else {
            serde_json::from_slice(&bytes)
                .unwrap_or(Value::String(String::from_utf8_lossy(&bytes).into_owned()))
        };
        Ok(ExecuteResponse {
            status_code: status,
            headers: headers_out,
            body: body_json,
        })
    }

    /// `GET /api/v1/admin/scripts/{id}/logs?limit=N`
    pub async fn logs_list(&self, script_id: &str, limit: u32) -> Result<Vec<ExecutionLog>> {
        let resp = self
            .request(
                Method::GET,
                &format!("/api/v1/admin/scripts/{script_id}/logs?limit={limit}"),
            )
            .send()
            .await?;
        decode(resp).await
    }

    /// `POST /api/v1/admin/auth/logout` — best-effort: server returns
    /// 204 whether or not the token matched a live session, so we just
    /// fire and discard the body. Caller still wipes the local creds.
    pub async fn auth_logout(&self) -> Result<()> {
        let resp = self
            .request(Method::POST, "/api/v1/admin/auth/logout")
            .send()
            .await?;
        decode_status(resp).await
    }

    /// `GET /api/v1/admin/api-keys` — caller's keys only (server filters
    /// by user_id, no cross-user enumeration).
    pub async fn apikeys_list(&self) -> Result<Vec<ApiKeyDto>> {
        let resp = self
            .request(Method::GET, "/api/v1/admin/api-keys")
            .send()
            .await?;
        decode(resp).await
    }

    /// `POST /api/v1/admin/api-keys` — `raw_token` is in the response
    /// **once** and never appears in `GET /api-keys` afterward.
    pub async fn apikeys_mint(&self, body: &MintApiKeyBody<'_>) -> Result<MintApiKeyResponseDto> {
        let resp = self
            .request(Method::POST, "/api/v1/admin/api-keys")
            .json(body)
            .send()
            .await?;
        decode(resp).await
    }

    /// `DELETE /api/v1/admin/api-keys/{id}` — 404 covers both "doesn't
    /// exist" and "not yours" (server flattens to avoid enumeration).
    pub async fn apikeys_delete(&self, id: &str) -> Result<()> {
        let resp = self
            .request(Method::DELETE, &format!("/api/v1/admin/api-keys/{id}"))
            .send()
            .await?;
        decode_status(resp).await
    }
}

/// `POST /api/v1/admin/auth/login` — sits outside the `Client` because
/// it runs before any token exists. Mirrors the dashboard's login.ts
/// wire shape (see `manager-core/src/auth_api.rs:49-60`).
pub async fn auth_login(url: &str, username: &str, password: &str) -> Result<LoginResponseDto> {
    let http = reqwest::Client::builder()
        .user_agent(concat!("pic/", env!("CARGO_PKG_VERSION")))
        .build()
        .context("building HTTP client")?;
    let body = LoginRequestBody { username, password };
    let resp = http
        .post(format!(
            "{}/api/v1/admin/auth/login",
            url.trim_end_matches('/')
        ))
        .json(&body)
        .send()
        .await?;
    decode(resp).await
}

// ---------- DTOs (CLI-local, wire-shape-matched) ----------

#[allow(dead_code)]
#[derive(Debug, Deserialize)]
pub struct AuthMeDto {
    // Part of the wire shape (and kept for symmetry with the dashboard's
    // MeDto), even though the CLI never displays it.
    pub id: String,
    pub username: String,
    pub instance_role: InstanceRole,
    #[serde(default)]
    pub email: Option<String>,
}

#[allow(dead_code)]
#[derive(Debug, Deserialize)]
pub struct AppLookupDto {
    #[serde(flatten)]
    pub app: App,
    // Not surfaced yet — `pic apps ls` only shows what `apps_list` returns.
    // Kept on the DTO so future `pic apps inspect <slug>` work is one-line.
    #[serde(default)]
    pub my_role: Option<AppRole>,
}

#[derive(Debug, Serialize)]
pub struct CreateAppBody<'a> {
    pub slug: &'a str,
    pub name: &'a str,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub description: Option<&'a str>,
}

#[derive(Debug, Serialize)]
pub struct CreateScriptBody<'a> {
    pub app_id: AppId,
    pub name: &'a str,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub description: Option<&'a str>,
    pub source: &'a str,
}

#[derive(Debug, Serialize)]
struct UpdateScriptBody<'a> {
    source: &'a str,
}

#[derive(Debug, Serialize)]
struct LoginRequestBody<'a> {
    username: &'a str,
    password: &'a str,
}

#[allow(dead_code)]
#[derive(Debug, Deserialize)]
pub struct LoginResponseDto {
    pub user: LoginUserDto,
    pub token: String,
    pub expires_at: DateTime<Utc>,
}

#[allow(dead_code)]
#[derive(Debug, Deserialize)]
pub struct LoginUserDto {
    pub id: AdminUserId,
    pub username: String,
    pub instance_role: InstanceRole,
    #[serde(default)]
    pub email: Option<String>,
}

#[derive(Debug, Serialize)]
pub struct MintApiKeyBody<'a> {
    pub name: &'a str,
    pub scopes: &'a [Scope],
    #[serde(skip_serializing_if = "Option::is_none")]
    pub app_id: Option<AppId>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub expires_at: Option<DateTime<Utc>>,
}

/// Fresh-mint response. The `raw_token` field is the one and only
/// chance to capture the bearer string; subsequent `GET /api-keys`
/// returns the `ApiKeyDto` portion without it.
#[derive(Debug, Deserialize)]
pub struct MintApiKeyResponseDto {
    #[serde(flatten)]
    pub key: ApiKeyDto,
    pub raw_token: String,
}

#[allow(dead_code)]
#[derive(Debug, Deserialize)]
pub struct ApiKeyDto {
    pub id: ApiKeyId,
    pub prefix: String,
    pub name: String,
    pub scopes: Vec<Scope>,
    pub app_id: Option<AppId>,
    pub expires_at: Option<DateTime<Utc>>,
    pub last_used_at: Option<DateTime<Utc>>,
    pub created_at: DateTime<Utc>,
}

#[allow(dead_code)]
#[derive(Debug)]
pub struct ExecuteResponse {
    pub status_code: u16,
    // Captured for completeness; not displayed today, but `pic invoke -v`
    // could surface them later without changing this struct.
    pub headers: BTreeMap<String, String>,
    pub body: Value,
}

// ---------- helpers ----------

/// Parse `-H "Key: value"` or `-H "Key=value"` into a `(name, value)`
/// pair. Trims surrounding whitespace on both sides.
pub fn parse_kv_header(raw: &str) -> Result<(String, String), String> {
    let (k, v) = raw
        .split_once(':')
        .or_else(|| raw.split_once('='))
        .ok_or_else(|| format!("expected `Key: value` or `Key=value`, got {raw:?}"))?;
    let k = k.trim();
    let v = v.trim();
    if k.is_empty() {
        return Err(format!("empty header name in {raw:?}"));
    }
    Ok((k.to_string(), v.to_string()))
}

fn urlencoded(s: &str) -> String {
    // Minimal pass: percent-encode the few chars that break the query.
    // Slugs and UUIDs don't contain them in practice, but be safe.
    let mut out = String::with_capacity(s.len());
    for ch in s.chars() {
        match ch {
            '&' | '=' | '?' | '#' | ' ' => {
                out.push_str(&format!("%{:02X}", u32::from(ch)));
            }
            _ => out.push(ch),
        }
    }
    out
}

async fn decode<T: for<'de> Deserialize<'de>>(resp: reqwest::Response) -> Result<T> {
    if resp.status().is_success() {
        return resp.json::<T>().await.context("parsing response body");
    }
    Err(server_error(resp).await)
}

/// Like `decode` but for endpoints whose 2xx response has no body
/// (204 No Content) — DELETE handlers, logout.
async fn decode_status(resp: reqwest::Response) -> Result<()> {
    if resp.status().is_success() {
        return Ok(());
    }
    Err(server_error(resp).await)
}

async fn server_error(resp: reqwest::Response) -> anyhow::Error {
    let status = resp.status();
    let body = resp.text().await.unwrap_or_default();
    let msg = parse_error_body(&body).unwrap_or(body);
    let hint = role_hint(status);
    if hint.is_empty() {
        anyhow!("HTTP {}: {}", status.as_u16(), msg)
    } else {
        anyhow!("HTTP {}: {} ({})", status.as_u16(), msg, hint)
    }
}

fn parse_error_body(s: &str) -> Option<String> {
    let v: Value = serde_json::from_str(s).ok()?;
    let obj = v.as_object()?;
    if let Some(m) = obj.get("message").and_then(Value::as_str) {
        return Some(m.to_string());
    }
    if let Some(e) = obj.get("error").and_then(Value::as_str) {
        return Some(e.to_string());
    }
    None
}

fn role_hint(status: StatusCode) -> &'static str {
    match status {
        StatusCode::FORBIDDEN => "your role may lack the required capability; check `pic whoami`",
        StatusCode::UNAUTHORIZED => "token rejected; re-run `pic login`",
        _ => "",
    }
}

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

    #[test]
    fn parse_kv_colon() {
        let (k, v) = parse_kv_header("X-Foo: bar").unwrap();
        assert_eq!(k, "X-Foo");
        assert_eq!(v, "bar");
    }

    #[test]
    fn parse_kv_equals() {
        let (k, v) = parse_kv_header("X-Foo=bar").unwrap();
        assert_eq!(k, "X-Foo");
        assert_eq!(v, "bar");
    }

    #[test]
    fn parse_kv_rejects_no_separator() {
        assert!(parse_kv_header("X-Foo").is_err());
    }

    #[test]
    fn parse_kv_rejects_empty_name() {
        assert!(parse_kv_header(": bar").is_err());
    }

    #[test]
    fn url_strip_trailing_slash() {
        let c = Client::new("http://localhost:8000/", "pic_x").unwrap();
        assert_eq!(c.url(), "http://localhost:8000");
    }
}