use ratatui::layout::Rect;
use ratatui::style::{Modifier, Style};
use ratatui::text::{Line, Span};
use ratatui::widgets::{Block, Borders, Paragraph};
use ratatui::Frame;

use crate::app::App;
use crate::engine::LinkState;
use crate::midi;
use crate::state::OptionsFocus;
use crate::theme;
use crate::widgets::{render_scroll_indicators, IndicatorAlign};

pub fn render(frame: &mut Frame, app: &App, link: &LinkState, area: Rect) {
    let theme = theme::get();

    let block = Block::default()
        .borders(Borders::ALL)
        .title(" Options ")
        .border_style(Style::new().fg(theme.modal.input));

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

    let padded = Rect {
        x: inner.x + 2,
        y: inner.y + 1,
        width: inner.width.saturating_sub(4),
        height: inner.height.saturating_sub(2),
    };

    let focus = app.options.focus;
    let content_width = padded.width as usize;

    let enabled = link.is_enabled();
    let peers = link.peers();
    let (status_text, status_color) = if !enabled {
        ("DISABLED", theme.link_status.disabled)
    } else if peers > 0 {
        ("CONNECTED", theme.link_status.connected)
    } else {
        ("LISTENING", theme.link_status.listening)
    };
    let peer_text = if enabled && peers > 0 {
        if peers == 1 {
            " · 1 peer".to_string()
        } else {
            format!(" · {peers} peers")
        }
    } else {
        String::new()
    };

    let link_header = Line::from(vec![
        Span::styled(
            "ABLETON LINK",
            Style::new().fg(theme.ui.header).add_modifier(Modifier::BOLD),
        ),
        Span::raw("  "),
        Span::styled(
            status_text,
            Style::new().fg(status_color).add_modifier(Modifier::BOLD),
        ),
        Span::styled(peer_text, Style::new().fg(theme.ui.text_muted)),
    ]);

    let quantum_str = format!("{:.0}", link.quantum());
    let tempo_str = format!("{:.1} BPM", link.tempo());
    let beat_str = format!("{:.2}", link.beat());
    let phase_str = format!("{:.2}", link.phase());

    let tempo_style = Style::new().fg(theme.values.tempo).add_modifier(Modifier::BOLD);
    let value_style = Style::new().fg(theme.values.value);

    let midi_outputs = midi::list_midi_outputs();
    let midi_inputs = midi::list_midi_inputs();

    let midi_out_display = |slot: usize| -> String {
        if let Some(idx) = app.midi.selected_outputs[slot] {
            midi_outputs
                .get(idx)
                .map(|d| d.name.clone())
                .unwrap_or_else(|| "(disconnected)".to_string())
        } else if midi_outputs.is_empty() {
            "(none found)".to_string()
        } else {
            "(not connected)".to_string()
        }
    };

    let midi_in_display = |slot: usize| -> String {
        if let Some(idx) = app.midi.selected_inputs[slot] {
            midi_inputs
                .get(idx)
                .map(|d| d.name.clone())
                .unwrap_or_else(|| "(disconnected)".to_string())
        } else if midi_inputs.is_empty() {
            "(none found)".to_string()
        } else {
            "(not connected)".to_string()
        }
    };

    let midi_out_0 = midi_out_display(0);
    let midi_out_1 = midi_out_display(1);
    let midi_out_2 = midi_out_display(2);
    let midi_out_3 = midi_out_display(3);
    let midi_in_0 = midi_in_display(0);
    let midi_in_1 = midi_in_display(1);
    let midi_in_2 = midi_in_display(2);
    let midi_in_3 = midi_in_display(3);

    let hue_str = format!("{}°", app.ui.hue_rotation as i32);

    let lines: Vec<Line> = vec![
        render_section_header("DISPLAY", &theme),
        render_divider(content_width, &theme),
        render_option_line(
            "Theme",
            app.ui.color_scheme.label(),
            focus == OptionsFocus::ColorScheme,
            &theme,
        ),
        render_option_line(
            "Hue rotation",
            &hue_str,
            focus == OptionsFocus::HueRotation,
            &theme,
        ),
        render_option_line(
            "Refresh rate",
            app.audio.config.refresh_rate.label(),
            focus == OptionsFocus::RefreshRate,
            &theme,
        ),
        render_option_line(
            "Runtime highlight",
            if app.ui.runtime_highlight { "On" } else { "Off" },
            focus == OptionsFocus::RuntimeHighlight,
            &theme,
        ),
        render_option_line(
            "Show scope",
            if app.audio.config.show_scope { "On" } else { "Off" },
            focus == OptionsFocus::ShowScope,
            &theme,
        ),
        render_option_line(
            "Show spectrum",
            if app.audio.config.show_spectrum {
                "On"
            } else {
                "Off"
            },
            focus == OptionsFocus::ShowSpectrum,
            &theme,
        ),
        render_option_line(
            "Completion",
            if app.ui.show_completion { "On" } else { "Off" },
            focus == OptionsFocus::ShowCompletion,
            &theme,
        ),
        Line::from(""),
        link_header,
        render_divider(content_width, &theme),
        render_option_line(
            "Enabled",
            if link.is_enabled() { "On" } else { "Off" },
            focus == OptionsFocus::LinkEnabled,
            &theme,
        ),
        render_option_line(
            "Start/Stop sync",
            if link.is_start_stop_sync_enabled() {
                "On"
            } else {
                "Off"
            },
            focus == OptionsFocus::StartStopSync,
            &theme,
        ),
        render_option_line("Quantum", &quantum_str, focus == OptionsFocus::Quantum, &theme),
        Line::from(""),
        render_section_header("SESSION", &theme),
        render_divider(content_width, &theme),
        render_readonly_line("Tempo", &tempo_str, tempo_style, &theme),
        render_readonly_line("Beat", &beat_str, value_style, &theme),
        render_readonly_line("Phase", &phase_str, value_style, &theme),
        Line::from(""),
        render_section_header("MIDI OUTPUTS", &theme),
        render_divider(content_width, &theme),
        render_option_line("Output 0", &midi_out_0, focus == OptionsFocus::MidiOutput0, &theme),
        render_option_line("Output 1", &midi_out_1, focus == OptionsFocus::MidiOutput1, &theme),
        render_option_line("Output 2", &midi_out_2, focus == OptionsFocus::MidiOutput2, &theme),
        render_option_line("Output 3", &midi_out_3, focus == OptionsFocus::MidiOutput3, &theme),
        Line::from(""),
        render_section_header("MIDI INPUTS", &theme),
        render_divider(content_width, &theme),
        render_option_line("Input 0", &midi_in_0, focus == OptionsFocus::MidiInput0, &theme),
        render_option_line("Input 1", &midi_in_1, focus == OptionsFocus::MidiInput1, &theme),
        render_option_line("Input 2", &midi_in_2, focus == OptionsFocus::MidiInput2, &theme),
        render_option_line("Input 3", &midi_in_3, focus == OptionsFocus::MidiInput3, &theme),
    ];

    let total_lines = lines.len();
    let max_visible = padded.height as usize;

    let focus_line = focus.line_index();

    let scroll_offset = if total_lines <= max_visible {
        0
    } else {
        focus_line
            .saturating_sub(max_visible / 2)
            .min(total_lines.saturating_sub(max_visible))
    };

    let visible_end = (scroll_offset + max_visible).min(total_lines);
    let visible_lines: Vec<Line> = lines
        .into_iter()
        .skip(scroll_offset)
        .take(visible_end - scroll_offset)
        .collect();

    frame.render_widget(Paragraph::new(visible_lines), padded);

    render_scroll_indicators(
        frame,
        padded,
        scroll_offset,
        visible_end - scroll_offset,
        total_lines,
        theme.ui.text_dim,
        IndicatorAlign::Right,
    );
}

fn render_section_header(title: &str, theme: &theme::ThemeColors) -> Line<'static> {
    Line::from(Span::styled(
        title.to_string(),
        Style::new().fg(theme.ui.header).add_modifier(Modifier::BOLD),
    ))
}

fn render_divider(width: usize, theme: &theme::ThemeColors) -> Line<'static> {
    Line::from(Span::styled(
        "─".repeat(width),
        Style::new().fg(theme.ui.border),
    ))
}

fn render_option_line<'a>(label: &'a str, value: &'a str, focused: bool, theme: &theme::ThemeColors) -> Line<'a> {
    let highlight = Style::new().fg(theme.hint.key).add_modifier(Modifier::BOLD);
    let normal = Style::new().fg(theme.ui.text_primary);
    let label_style = Style::new().fg(theme.ui.text_muted);

    let prefix = if focused { "> " } else { "  " };
    let prefix_style = if focused { highlight } else { normal };

    let value_display = if focused {
        format!("< {value} >")
    } else {
        format!("  {value}  ")
    };
    let value_style = if focused { highlight } else { normal };

    let label_width = 20;
    let padded_label = format!("{label:<label_width$}");

    Line::from(vec![
        Span::styled(prefix, prefix_style),
        Span::styled(padded_label, label_style),
        Span::styled(value_display, value_style),
    ])
}

fn render_readonly_line<'a>(label: &'a str, value: &'a str, value_style: Style, theme: &theme::ThemeColors) -> Line<'a> {
    let label_style = Style::new().fg(theme.ui.text_muted);
    let label_width = 20;
    let padded_label = format!("{label:<label_width$}");

    Line::from(vec![
        Span::raw("  "),
        Span::styled(padded_label, label_style),
        Span::styled(format!("  {value}"), value_style),
    ])
}