//! HTML page handlers using askama templates for the htmx + Alpine.js frontend.

use askama::Template;
use axum::extract::{Path, Query, State};
use axum::http::StatusCode;
use axum::response::{Html, IntoResponse, Redirect, Response};
use axum::routing::{get, post};
use axum::{Form, Json};
use axum::Router;

use crate::config::Config;
use crate::daemon::{DaemonStatus, ShareStatus};
use crate::web::SharedState;

pub fn routes() -> Router<SharedState> {
    Router::new()
        // Full-page routes (serve layout shell with embedded tab content)
        .route("/", get(page_dashboard))
        .route("/shares", get(page_shares))
        .route("/shares/{name}", get(share_redirect))
        .route("/config", get(page_config))
        .route("/config", post(config_submit))
        .route("/config/apply", post(config_apply))
        .route("/logs", get(page_logs))
        // Tab partial routes (htmx async load)
        .route("/tabs/dashboard", get(tab_dashboard))
        .route("/tabs/shares", get(tab_shares))
        .route("/tabs/config", get(tab_config))
        .route("/tabs/logs", get(tab_logs))
        // Legacy compatibility
        .route("/partials/status", get(status_partial))
}

// ─── View models ──────────────────────────────────────────────────────────

/// Compact share view for dashboard cards and status partial.
#[allow(dead_code)] // fields used by askama templates
struct ShareView {
    name: String,
    connection: String,
    mount_point: String,
    mounted: bool,
    cache_display: String,
    dirty_count: u64,
    speed_display: String,
    read_only: bool,
    health: String,
    health_message: String,
    warmup_state: String,
    warmup_done: usize,
    warmup_total: usize,
    dir_refresh_active: bool,
    last_dir_refresh_ago: String,
}

/// Extended share view for the shares table with all detail fields.
#[allow(dead_code)] // fields used by askama templates
struct ShareDetailView {
    name: String,
    connection: String,
    mount_point: String,
    remote_path: String,
    mounted: bool,
    read_only: bool,
    rc_port: u16,
    cache_display: String,
    dirty_count: u64,
    errored_files: u64,
    speed_display: String,
    transfers: u64,
    errors: u64,
    health: String,
    health_message: String,
    warmup_state: String,
    warmup_done: usize,
    warmup_total: usize,
    warmup_rules: Vec<WarmupRuleView>,
    dir_refresh_active: bool,
    last_dir_refresh_ago: String,
}

/// View model for a single warmup rule in the shares detail panel.
#[allow(dead_code)]
struct WarmupRuleView {
    path: String,
    newer_than: String,
    state: String,
    badge_class: String,
    total_files: usize,
    skipped: usize,
    cached: usize,
    errors: usize,
}

/// Build compact share views from status + config.
fn build_share_views(status: &DaemonStatus, config: &Config) -> Vec<ShareView> {
    status
        .shares
        .iter()
        .map(|s| {
            let sc = config.find_share(&s.name);
            let (warmup_state, warmup_done, warmup_total) =
                status.warmup_summary_for(&s.name);
            let dir_refresh_active = sc
                .map(|sc| config.effective_dir_refresh_interval(sc).is_some())
                .unwrap_or(false);
            let last_dir_refresh_ago = status.dir_refresh_ago_for(&s.name).unwrap_or_default();
            ShareView {
                name: s.name.clone(),
                connection: sc.map(|c| c.connection.clone()).unwrap_or_default(),
                mount_point: sc
                    .map(|c| c.mount_point.display().to_string())
                    .unwrap_or_default(),
                mounted: s.mounted,
                cache_display: s.cache_display(),
                dirty_count: s.dirty_count,
                speed_display: s.speed_display(),
                read_only: sc.map(|c| c.read_only).unwrap_or(false),
                health: s.health_label().to_string(),
                health_message: s.health_message().unwrap_or("").to_string(),
                warmup_state: warmup_state.to_string(),
                warmup_done,
                warmup_total,
                dir_refresh_active,
                last_dir_refresh_ago,
            }
        })
        .collect()
}

/// Build extended share detail views from status + config.
fn build_share_detail_views(status: &DaemonStatus, config: &Config) -> Vec<ShareDetailView> {
    status
        .shares
        .iter()
        .map(|s| {
            let sc = config.find_share(&s.name);
            let (warmup_state, warmup_done, warmup_total) =
                status.warmup_summary_for(&s.name);
            let dir_refresh_active = sc
                .map(|sc| config.effective_dir_refresh_interval(sc).is_some())
                .unwrap_or(false);
            let last_dir_refresh_ago = status.dir_refresh_ago_for(&s.name).unwrap_or_default();

            // Build per-rule views for this share
            let warmup_rules: Vec<WarmupRuleView> = status
                .warmup
                .iter()
                .filter(|r| r.share == s.name)
                .map(|r| {
                    let (state_str, badge_class) = match &r.state {
                        crate::daemon::WarmupRuleState::Pending => ("pending", "warn"),
                        crate::daemon::WarmupRuleState::Listing => ("listing", "warmup"),
                        crate::daemon::WarmupRuleState::Caching => ("caching", "warmup"),
                        crate::daemon::WarmupRuleState::Complete => ("complete", "ok"),
                        crate::daemon::WarmupRuleState::Failed(_) => ("failed", "error"),
                    };
                    WarmupRuleView {
                        path: r.path.clone(),
                        newer_than: r.newer_than.clone().unwrap_or_default(),
                        state: state_str.to_string(),
                        badge_class: badge_class.to_string(),
                        total_files: r.total_files,
                        skipped: r.skipped,
                        cached: r.cached,
                        errors: r.errors,
                    }
                })
                .collect();

            ShareDetailView {
                name: s.name.clone(),
                connection: sc.map(|c| c.connection.clone()).unwrap_or_default(),
                mount_point: sc
                    .map(|c| c.mount_point.display().to_string())
                    .unwrap_or_default(),
                remote_path: sc.map(|c| c.remote_path.clone()).unwrap_or_default(),
                mounted: s.mounted,
                read_only: sc.map(|c| c.read_only).unwrap_or(false),
                rc_port: s.rc_port,
                cache_display: s.cache_display(),
                dirty_count: s.dirty_count,
                errored_files: s.errored_files,
                speed_display: s.speed_display(),
                transfers: s.transfers,
                errors: s.errors,
                health: s.health_label().to_string(),
                health_message: s.health_message().unwrap_or("").to_string(),
                warmup_state: warmup_state.to_string(),
                warmup_done,
                warmup_total,
                warmup_rules,
                dir_refresh_active,
                last_dir_refresh_ago,
            }
        })
        .collect()
}

/// Aggregate stats from share statuses.
fn aggregate_stats(shares: &[ShareStatus]) -> (u64, f64, u64) {
    let total_cache: u64 = shares.iter().map(|s| s.cache_bytes).sum();
    let total_speed: f64 = shares.iter().map(|s| s.speed).sum();
    let active_transfers: u64 = shares.iter().map(|s| s.transfers).sum();
    (total_cache, total_speed, active_transfers)
}

fn format_bytes(bytes: u64) -> String {
    const KIB: f64 = 1024.0;
    const MIB: f64 = KIB * 1024.0;
    const GIB: f64 = MIB * 1024.0;
    const TIB: f64 = GIB * 1024.0;
    let b = bytes as f64;
    if b >= TIB {
        format!("{:.1} TiB", b / TIB)
    } else if b >= GIB {
        format!("{:.1} GiB", b / GIB)
    } else if b >= MIB {
        format!("{:.1} MiB", b / MIB)
    } else if b >= KIB {
        format!("{:.1} KiB", b / KIB)
    } else {
        format!("{bytes} B")
    }
}

fn format_speed(speed: f64) -> String {
    if speed < 1.0 {
        "-".to_string()
    } else {
        format!("{}/s", format_bytes(speed as u64))
    }
}

// ─── Templates ────────────────────────────────────────────────────────────

#[derive(Template)]
#[template(path = "web/layout.html", escape = "none")]
struct LayoutTemplate {
    active_tab: String,
    tab_content: String,
    uptime: String,
    config_path: String,
    nas_offline: bool,
}

#[derive(Template)]
#[template(path = "web/tabs/dashboard.html")]
struct DashboardTabTemplate {
    total_shares: usize,
    healthy_count: usize,
    #[allow(dead_code)]
    failed_count: usize,
    total_cache_display: String,
    aggregate_speed_display: String,
    active_transfers: u64,
    shares: Vec<ShareView>,
    smbd_running: bool,
    webdav_running: bool,
    nfs_exported: bool,
    all_synced: bool,
}

#[derive(Template)]
#[template(path = "web/tabs/shares.html")]
struct SharesTabTemplate {
    shares: Vec<ShareDetailView>,
    expand: String,
}

#[derive(Template)]
#[template(path = "web/tabs/config.html", escape = "none")]
struct ConfigTabTemplate {
    init_json: String,
}

/// Data embedded as JSON for the Alpine.js config editor.
#[derive(serde::Serialize)]
struct ConfigTabInit {
    config: Config,
    message: Option<String>,
    is_error: bool,
}

/// JSON response for the `POST /config/apply` endpoint.
#[derive(serde::Serialize)]
struct ConfigApplyResponse {
    ok: bool,
    message: String,
}

#[derive(Template)]
#[template(path = "web/tabs/logs.html")]
struct LogsTabTemplate;

/// Legacy htmx polling partial (backward compat for `/partials/status`).
#[derive(Template)]
#[template(path = "web/tabs/dashboard.html")]
struct StatusPartialTemplate {
    total_shares: usize,
    healthy_count: usize,
    #[allow(dead_code)]
    failed_count: usize,
    total_cache_display: String,
    aggregate_speed_display: String,
    active_transfers: u64,
    shares: Vec<ShareView>,
    smbd_running: bool,
    webdav_running: bool,
    nfs_exported: bool,
    all_synced: bool,
}

// ─── Full-page handlers (layout shell + tab content) ──────────────────────

async fn page_dashboard(State(state): State<SharedState>) -> Response {
    render_layout("dashboard", &state, |status, config| {
        render_dashboard_tab(status, config)
    })
}

async fn page_shares(
    State(state): State<SharedState>,
    Query(params): Query<ExpandQuery>,
) -> Response {
    let expand = params.expand.unwrap_or_default();
    render_layout("shares", &state, |status, config| {
        render_shares_tab(status, config, &expand)
    })
}

async fn page_config(State(state): State<SharedState>) -> Response {
    render_layout("config", &state, |_status, config| {
        render_config_tab_html(config, None, false)
    })
}

async fn page_logs(State(state): State<SharedState>) -> Response {
    render_layout("logs", &state, |_status, _config| {
        LogsTabTemplate.render().unwrap_or_default()
    })
}

/// Helper: render the layout shell wrapping a tab content generator.
fn render_layout(
    tab: &str,
    state: &SharedState,
    tab_fn: impl FnOnce(&DaemonStatus, &Config) -> String,
) -> Response {
    let status = state.status.read().unwrap();
    let config = state.config.read().unwrap();

    let tab_content = tab_fn(&status, &config);

    let tmpl = LayoutTemplate {
        active_tab: tab.to_string(),
        tab_content,
        uptime: status.uptime_string(),
        config_path: state.config_path.display().to_string(),
        nas_offline: status.nas_offline,
    };

    match tmpl.render() {
        Ok(html) => Html(html).into_response(),
        Err(e) => (StatusCode::INTERNAL_SERVER_ERROR, format!("Template error: {e}")).into_response(),
    }
}

// ─── Tab partial handlers (htmx async) ───────────────────────────────────

#[derive(serde::Deserialize)]
struct ExpandQuery {
    expand: Option<String>,
}

async fn tab_dashboard(State(state): State<SharedState>) -> Response {
    let status = state.status.read().unwrap();
    let config = state.config.read().unwrap();
    let html = render_dashboard_tab(&status, &config);
    Html(html).into_response()
}

async fn tab_shares(
    State(state): State<SharedState>,
    Query(params): Query<ExpandQuery>,
) -> Response {
    let status = state.status.read().unwrap();
    let config = state.config.read().unwrap();
    let expand = params.expand.unwrap_or_default();
    let html = render_shares_tab(&status, &config, &expand);
    Html(html).into_response()
}

async fn tab_config(State(state): State<SharedState>) -> Response {
    let config = state.config.read().unwrap();
    let html = render_config_tab_html(&config, None, false);
    Html(html).into_response()
}

async fn tab_logs() -> Response {
    match LogsTabTemplate.render() {
        Ok(html) => Html(html).into_response(),
        Err(e) => (StatusCode::INTERNAL_SERVER_ERROR, format!("Template error: {e}")).into_response(),
    }
}

// ─── Tab render helpers ───────────────────────────────────────────────────

fn render_dashboard_tab(status: &DaemonStatus, config: &Config) -> String {
    let shares = build_share_views(status, config);
    let healthy_count = shares.iter().filter(|s| s.health == "OK").count();
    let failed_count = shares.iter().filter(|s| s.health == "FAILED").count();
    let (total_cache, total_speed, active_transfers) = aggregate_stats(&status.shares);
    let all_synced = status.all_synced;

    let tmpl = DashboardTabTemplate {
        total_shares: shares.len(),
        healthy_count,
        failed_count,
        total_cache_display: format_bytes(total_cache),
        aggregate_speed_display: format_speed(total_speed),
        active_transfers,
        shares,
        smbd_running: status.smbd_running,
        webdav_running: status.webdav_running,
        nfs_exported: status.nfs_exported,
        all_synced,
    };

    tmpl.render().unwrap_or_default()
}

fn render_shares_tab(status: &DaemonStatus, config: &Config, expand: &str) -> String {
    let shares = build_share_detail_views(status, config);

    let tmpl = SharesTabTemplate {
        shares,
        expand: expand.to_string(),
    };

    tmpl.render().unwrap_or_default()
}

// ─── Share detail redirect ────────────────────────────────────────────────

async fn share_redirect(Path(name): Path<String>) -> Response {
    Redirect::to(&format!("/shares?expand={name}")).into_response()
}

// ─── Config submit ────────────────────────────────────────────────────────

#[derive(serde::Deserialize)]
struct ConfigForm {
    toml: String,
}

async fn config_submit(
    State(state): State<SharedState>,
    Form(form): Form<ConfigForm>,
) -> Response {
    // Parse and validate
    let new_config: Config = match toml::from_str(&form.toml) {
        Ok(c) => c,
        Err(e) => {
            let config = state.config.read().unwrap();
            let html = render_config_tab_html(
                &config,
                Some(format!("TOML parse error: {e}")),
                true,
            );
            return Html(html).into_response();
        }
    };

    if let Err(e) = new_config.validate() {
        let html = render_config_tab_html(
            &new_config,
            Some(format!("Validation error: {e}")),
            true,
        );
        return Html(html).into_response();
    }

    // Compute diff 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() {
            let html = render_config_tab_html(
                &new_config,
                Some("No changes detected.".to_string()),
                false,
            );
            return Html(html).into_response();
        }
        d.summary()
    };

    // Save to disk
    if let Err(e) = std::fs::write(&state.config_path, &form.toml) {
        let html = render_config_tab_html(
            &new_config,
            Some(format!("Failed to write config: {e}")),
            true,
        );
        return Html(html).into_response();
    }

    // Send reload command
    if let Err(e) = state
        .cmd_tx
        .send(crate::daemon::SupervisorCmd::Reload(new_config))
    {
        let config = state.config.read().unwrap();
        let html = render_config_tab_html(
            &config,
            Some(format!("Failed to send reload: {e}")),
            true,
        );
        return Html(html).into_response();
    }

    // Success — re-read config and show success message
    let config = state.config.read().unwrap();
    let html = render_config_tab_html(
        &config,
        Some(format!("Config applied: {diff_summary}")),
        false,
    );
    Html(html).into_response()
}

/// JSON endpoint: apply config from the interactive form editor.
async fn config_apply(
    State(state): State<SharedState>,
    Json(new_config): Json<Config>,
) -> Json<ConfigApplyResponse> {
    // Validate
    if let Err(e) = new_config.validate() {
        return Json(ConfigApplyResponse {
            ok: false,
            message: format!("Validation error: {e}"),
        });
    }

    // Compute diff
    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 Json(ConfigApplyResponse {
                ok: true,
                message: "No changes detected.".to_string(),
            });
        }
        d.summary()
    };

    // Serialize to human-readable TOML and write to disk
    let toml_content = new_config.to_commented_toml();

    if let Err(e) = std::fs::write(&state.config_path, &toml_content) {
        return Json(ConfigApplyResponse {
            ok: false,
            message: format!("Failed to write config: {e}"),
        });
    }

    // Send reload command
    if let Err(e) = state
        .cmd_tx
        .send(crate::daemon::SupervisorCmd::Reload(new_config))
    {
        return Json(ConfigApplyResponse {
            ok: false,
            message: format!("Failed to send reload: {e}"),
        });
    }

    tracing::info!("Config applied: {diff_summary}");

    Json(ConfigApplyResponse {
        ok: true,
        message: format!("Config applied: {diff_summary}"),
    })
}

/// Render the config tab HTML using the interactive form editor.
fn render_config_tab_html(config: &Config, message: Option<String>, is_error: bool) -> String {
    let init = ConfigTabInit {
        config: config.clone(),
        message,
        is_error,
    };
    // Escape </ to prevent breaking out of <script> tags
    let init_json = serde_json::to_string(&init)
        .unwrap_or_default()
        .replace("</", "<\\/");
    let tmpl = ConfigTabTemplate { init_json };
    tmpl.render().unwrap_or_default()
}

// ─── Legacy partial (backward compat) ─────────────────────────────────────

async fn status_partial(State(state): State<SharedState>) -> Response {
    let status = state.status.read().unwrap();
    let config = state.config.read().unwrap();

    let shares = build_share_views(&status, &config);
    let healthy_count = shares.iter().filter(|s| s.health == "OK").count();
    let failed_count = shares.iter().filter(|s| s.health == "FAILED").count();
    let (total_cache, total_speed, active_transfers) = aggregate_stats(&status.shares);

    let tmpl = StatusPartialTemplate {
        total_shares: shares.len(),
        healthy_count,
        failed_count,
        total_cache_display: format_bytes(total_cache),
        aggregate_speed_display: format_speed(total_speed),
        active_transfers,
        shares,
        smbd_running: status.smbd_running,
        webdav_running: status.webdav_running,
        nfs_exported: status.nfs_exported,
        all_synced: status.all_synced,
    };

    match tmpl.render() {
        Ok(html) => Html(html).into_response(),
        Err(e) => (StatusCode::INTERNAL_SERVER_ERROR, format!("Template error: {e}")).into_response(),
    }
}