//! JSON API handlers for programmatic access and future SPA.
//!
//! All endpoints return JSON. The htmx frontend uses the page handlers instead,
//! but these are available for CLI tools and external integrations.

use axum::extract::{Path, State};
use axum::http::StatusCode;
use axum::response::Json;
use axum::routing::{get, post};
use axum::Router;
use serde::Serialize;

use crate::daemon::SupervisorCmd;
use crate::web::SharedState;

pub fn routes() -> Router<SharedState> {
    Router::new()
        .route("/api/status", get(get_status))
        .route("/api/status/{share}", get(get_share_status))
        .route("/api/config", get(get_config))
        .route("/api/config", post(post_config))
        .route("/api/bwlimit", post(post_bwlimit))
}

/// GET /api/status — overall daemon status.
#[derive(Serialize)]
struct StatusResponse {
    uptime: String,
    shares: Vec<ShareStatusResponse>,
    smbd_running: bool,
    webdav_running: bool,
    nfs_exported: bool,
}

#[derive(Serialize)]
struct ShareStatusResponse {
    name: String,
    mounted: bool,
    rc_port: u16,
    cache_bytes: u64,
    cache_display: String,
    dirty_count: u64,
    errored_files: u64,
    speed: f64,
    speed_display: String,
    transfers: u64,
    errors: u64,
}

async fn get_status(State(state): State<SharedState>) -> Json<StatusResponse> {
    let status = state.status.read().unwrap();
    Json(StatusResponse {
        uptime: status.uptime_string(),
        shares: status
            .shares
            .iter()
            .map(|s| ShareStatusResponse {
                name: s.name.clone(),
                mounted: s.mounted,
                rc_port: s.rc_port,
                cache_bytes: s.cache_bytes,
                cache_display: s.cache_display(),
                dirty_count: s.dirty_count,
                errored_files: s.errored_files,
                speed: s.speed,
                speed_display: s.speed_display(),
                transfers: s.transfers,
                errors: s.errors,
            })
            .collect(),
        smbd_running: status.smbd_running,
        webdav_running: status.webdav_running,
        nfs_exported: status.nfs_exported,
    })
}

/// GET /api/status/{share} — per-share status.
async fn get_share_status(
    State(state): State<SharedState>,
    Path(share_name): Path<String>,
) -> Result<Json<ShareStatusResponse>, StatusCode> {
    let status = state.status.read().unwrap();
    let share = status
        .shares
        .iter()
        .find(|s| s.name == share_name)
        .ok_or(StatusCode::NOT_FOUND)?;
    Ok(Json(ShareStatusResponse {
        name: share.name.clone(),
        mounted: share.mounted,
        rc_port: share.rc_port,
        cache_bytes: share.cache_bytes,
        cache_display: share.cache_display(),
        dirty_count: share.dirty_count,
        errored_files: share.errored_files,
        speed: share.speed,
        speed_display: share.speed_display(),
        transfers: share.transfers,
        errors: share.errors,
    }))
}

/// GET /api/config — current config as JSON.
async fn get_config(State(state): State<SharedState>) -> Json<serde_json::Value> {
    let config = state.config.read().unwrap();
    Json(serde_json::to_value(&*config).unwrap_or_default())
}

/// POST /api/config — submit new config as TOML string.
#[derive(serde::Deserialize)]
struct ConfigSubmit {
    toml: String,
}

#[derive(Serialize)]
struct ConfigResponse {
    ok: bool,
    message: String,
    diff_summary: Option<String>,
}

async fn post_config(
    State(state): State<SharedState>,
    Json(body): Json<ConfigSubmit>,
) -> (StatusCode, Json<ConfigResponse>) {
    // Parse and validate the new config
    let new_config: crate::config::Config = match toml::from_str(&body.toml) {
        Ok(c) => c,
        Err(e) => {
            return (
                StatusCode::BAD_REQUEST,
                Json(ConfigResponse {
                    ok: false,
                    message: format!("TOML parse error: {e}"),
                    diff_summary: None,
                }),
            );
        }
    };

    if let Err(e) = new_config.validate() {
        return (
            StatusCode::BAD_REQUEST,
            Json(ConfigResponse {
                ok: false,
                message: format!("Validation error: {e}"),
                diff_summary: None,
            }),
        );
    }

    // Compute diff for summary
    let diff_summary = {
        let old_config = state.config.read().unwrap();
        let d = crate::config_diff::diff(&old_config, &new_config);
        if d.is_empty() {
            return (
                StatusCode::OK,
                Json(ConfigResponse {
                    ok: true,
                    message: "No changes detected".to_string(),
                    diff_summary: Some(d.summary()),
                }),
            );
        }
        d.summary()
    };

    // Save to disk
    if let Err(e) = std::fs::write(&state.config_path, &body.toml) {
        return (
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(ConfigResponse {
                ok: false,
                message: format!("Failed to write config file: {e}"),
                diff_summary: Some(diff_summary),
            }),
        );
    }

    // Send reload command to supervisor
    if let Err(e) = state.cmd_tx.send(SupervisorCmd::Reload(new_config)) {
        return (
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(ConfigResponse {
                ok: false,
                message: format!("Failed to send reload command: {e}"),
                diff_summary: Some(diff_summary),
            }),
        );
    }

    (
        StatusCode::OK,
        Json(ConfigResponse {
            ok: true,
            message: "Config applied successfully".to_string(),
            diff_summary: Some(diff_summary),
        }),
    )
}

/// POST /api/bwlimit — live bandwidth adjustment.
#[derive(serde::Deserialize)]
struct BwLimitRequest {
    #[serde(default = "default_bw")]
    up: String,
    #[serde(default = "default_bw")]
    down: String,
}

fn default_bw() -> String {
    "0".to_string()
}

#[derive(Serialize)]
struct BwLimitResponse {
    ok: bool,
    message: String,
}

async fn post_bwlimit(
    State(state): State<SharedState>,
    Json(body): Json<BwLimitRequest>,
) -> Json<BwLimitResponse> {
    match state
        .cmd_tx
        .send(SupervisorCmd::BwLimit {
            up: body.up,
            down: body.down,
        }) {
        Ok(()) => Json(BwLimitResponse {
            ok: true,
            message: "Bandwidth limit updated".to_string(),
        }),
        Err(e) => Json(BwLimitResponse {
            ok: false,
            message: format!("Failed to send command: {e}"),
        }),
    }
}