//! Blog post management screen — list, create, delete posts.

use makeover_tui::makeover_layout::{Column, Priority, Width};
use makeover_tui::table::{self, Cell, Sizing, TableStyle};
use ratatui::Frame;
use ratatui::layout::{Constraint, Layout, Rect};
use ratatui::style::{Modifier, Style};
use ratatui::text::{Line, Span};
use ratatui::widgets::{Block, Borders, Paragraph, TableState};

use super::App;

/// The post list's columns. Status carries the scheduled time as well as
/// published-or-draft, which is why it is the widest fixed track and why it
/// outranks the slug and the date.
const POST_COLUMNS: [Column<'static>; 4] = [
    Column {
        name: "Title",
        width: Width::Fill,
        priority: Priority::Essential,
        sortable: false,
        sorted: None,
    },
    Column {
        name: "Slug",
        width: Width::Fixed,
        priority: Priority::Optional,
        sortable: false,
        sorted: None,
    },
    Column {
        name: "Status",
        width: Width::Fixed,
        priority: Priority::Secondary,
        sortable: false,
        sorted: None,
    },
    Column {
        name: "Created",
        width: Width::Fixed,
        priority: Priority::Optional,
        sortable: false,
        sorted: None,
    },
];

/// The tracks the hand-written `Constraint`s carried.
const POST_SIZING: Sizing<'static> = Sizing {
    lengths: &[("Title", 20), ("Slug", 20), ("Status", 22), ("Created", 12)],
    fallback: 12,
};

pub(crate) fn render(frame: &mut Frame, app: &App) {
    let area = frame.area();

    let project_title = app.blog_project_title.as_deref().unwrap_or("Blog");

    let title = Line::from(vec![
        Span::styled(
            " Makenot.work ",
            Style::default().add_modifier(Modifier::BOLD),
        ),
        Span::raw(" -- "),
        Span::styled(project_title, Style::default().add_modifier(Modifier::BOLD)),
        Span::raw(" -- Blog "),
    ]);

    let block = Block::default()
        .title(title)
        .borders(Borders::ALL)
        .border_style(Style::default().fg(app.theme.line_border));

    let inner = block.inner(area);
    frame.render_widget(block, area);

    let chunks = Layout::vertical([
        Constraint::Length(1), // spacer
        Constraint::Length(1), // section header
        Constraint::Min(3),    // post list
        Constraint::Length(1), // status line
        Constraint::Length(1), // keybindings
    ])
    .split(inner);

    // Section header
    let count = app.blog_posts.len();
    let header = Paragraph::new(Line::from(vec![
        Span::raw("  "),
        Span::styled("Posts", Style::default().add_modifier(Modifier::BOLD)),
        if count == 0 {
            Span::raw("")
        } else {
            Span::raw(format!(" ({count})"))
        },
    ]));
    frame.render_widget(header, chunks[1]);

    // Post list
    if app.loading {
        let loading = Paragraph::new("  Loading...");
        frame.render_widget(loading, chunks[2]);
    } else if app.blog_posts.is_empty() {
        let empty = Paragraph::new("  No blog posts. Press [n] to create one.");
        frame.render_widget(empty, chunks[2]);
    } else {
        render_post_table(frame, app, chunks[2]);
    }

    // Status line
    if let Some(ref status) = app.blog_status {
        let style = if status.starts_with("Error") {
            Style::default().fg(app.theme.status_danger)
        } else {
            Style::default().fg(app.theme.status_success)
        };
        let status_line = Paragraph::new(Line::from(vec![
            Span::raw("  "),
            Span::styled(status.as_str(), style),
        ]));
        frame.render_widget(status_line, chunks[3]);
    }

    // Keybindings
    let mut key_spans = vec![
        Span::raw("  "),
        Span::styled("[j/k]", Style::default().add_modifier(Modifier::BOLD)),
        Span::raw(" Nav  "),
        Span::styled("[n]", Style::default().add_modifier(Modifier::BOLD)),
        Span::raw(" New  "),
    ];

    if !app.blog_posts.is_empty() {
        key_spans.extend([
            Span::styled("[d]", Style::default().add_modifier(Modifier::BOLD)),
            Span::raw(" Delete  "),
        ]);
    }

    key_spans.extend([
        Span::styled("[r]", Style::default().add_modifier(Modifier::BOLD)),
        Span::raw(" Refresh  "),
        Span::styled("[Esc]", Style::default().add_modifier(Modifier::BOLD)),
        Span::raw(" Back"),
    ]);

    let keys =
        Paragraph::new(Line::from(key_spans)).style(Style::default().fg(app.theme.content_muted));
    frame.render_widget(keys, chunks[4]);
}

fn render_post_table(frame: &mut Frame, app: &App, area: Rect) {
    let area = super::indent(area, 2);

    let rows: Vec<Vec<Cell>> = app
        .blog_posts
        .iter()
        .map(|post| {
            let status = if post.is_published {
                "published".to_string()
            } else if let Some(ref pa) = post.publish_at {
                let scheduled = pa.get(..16).unwrap_or(pa);
                format!("sched {scheduled}")
            } else {
                "draft".to_string()
            };

            vec![
                Cell::new("Title", post.title.as_str()),
                Cell::new("Slug", post.slug.as_str()),
                Cell::new("Status", status),
                Cell::new(
                    "Created",
                    post.created_at.get(..10).unwrap_or(&post.created_at),
                ),
            ]
        })
        .collect();

    let style = TableStyle::from_theme(&app.theme);
    let table = table::table(&POST_COLUMNS, &rows, &POST_SIZING, &style, area.width);
    let mut state = TableState::default().with_selected(Some(app.selected_index));
    frame.render_stateful_widget(table, area, &mut state);
}