use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
use std::sync::atomic::Ordering;

use super::{InputContext, InputResult};
use crate::commands::AppCommand;
use crate::model::categories;
use crate::model::docs;
use crate::state::{ConfirmAction, DictFocus, FlashKind, HelpFocus, Modal};

pub(super) fn handle_help_page(ctx: &mut InputContext, key: KeyEvent) -> InputResult {
    let ctrl = key.modifiers.contains(KeyModifiers::CONTROL);

    if ctx.app.ui.help_search_active {
        match key.code {
            KeyCode::Esc => ctx.dispatch(AppCommand::HelpClearSearch),
            KeyCode::Enter => ctx.dispatch(AppCommand::HelpSearchConfirm),
            KeyCode::Backspace => ctx.dispatch(AppCommand::HelpSearchBackspace),
            KeyCode::Char(c) if !ctrl => ctx.dispatch(AppCommand::HelpSearchInput(c)),
            _ => {}
        }
        return InputResult::Continue;
    }

    match key.code {
        KeyCode::Char('/') | KeyCode::Char('f') if key.code == KeyCode::Char('/') || ctrl => {
            ctx.dispatch(AppCommand::HelpActivateSearch);
        }
        KeyCode::Esc if !ctx.app.ui.help_search_query.is_empty() => {
            ctx.dispatch(AppCommand::HelpClearSearch);
        }
        KeyCode::Esc if ctx.app.ui.help_focused_block.is_some() => {
            ctx.app.ui.help_focused_block = None;
            ctx.app.ui.help_block_output = None;
        }
        KeyCode::Tab => ctx.dispatch(AppCommand::HelpToggleFocus),
        KeyCode::Left if ctx.app.ui.help_focus == HelpFocus::Topics => {
            collapse_help_section(ctx);
        }
        KeyCode::Right if ctx.app.ui.help_focus == HelpFocus::Topics => {
            expand_help_section(ctx);
        }
        KeyCode::Char('n') if ctx.app.ui.help_focus == HelpFocus::Content => {
            navigate_code_block(ctx, true);
        }
        KeyCode::Char('p') if ctx.app.ui.help_focus == HelpFocus::Content => {
            navigate_code_block(ctx, false);
        }
        KeyCode::Enter
            if ctx.app.ui.help_focus == HelpFocus::Content
                && ctx.app.ui.help_focused_block.is_some() =>
        {
            execute_focused_block(ctx);
        }
        KeyCode::Char('j') | KeyCode::Down if ctrl => {
            ctx.dispatch(AppCommand::HelpNextTopic(5));
        }
        KeyCode::Char('k') | KeyCode::Up if ctrl => {
            ctx.dispatch(AppCommand::HelpPrevTopic(5));
        }
        KeyCode::Char('j') | KeyCode::Down => match ctx.app.ui.help_focus {
            HelpFocus::Topics => ctx.dispatch(AppCommand::HelpNextTopic(1)),
            HelpFocus::Content => ctx.dispatch(AppCommand::HelpScrollDown(1)),
        },
        KeyCode::Char('k') | KeyCode::Up => match ctx.app.ui.help_focus {
            HelpFocus::Topics => ctx.dispatch(AppCommand::HelpPrevTopic(1)),
            HelpFocus::Content => ctx.dispatch(AppCommand::HelpScrollUp(1)),
        },
        KeyCode::PageDown => ctx.dispatch(AppCommand::HelpScrollDown(10)),
        KeyCode::PageUp => ctx.dispatch(AppCommand::HelpScrollUp(10)),
        KeyCode::Char('q') if !ctx.app.plugin_mode => {
            ctx.dispatch(AppCommand::OpenModal(Modal::Confirm {
                action: ConfirmAction::Quit,
                selected: false,
            }));
        }
        KeyCode::Char('s') => super::open_save(ctx),
        KeyCode::Char('l') => super::open_load(ctx),
        KeyCode::Char('?') => {
            ctx.dispatch(AppCommand::OpenModal(Modal::KeybindingsHelp { scroll: 0 }));
        }
        KeyCode::Char(' ') if !ctx.app.plugin_mode => {
            ctx.dispatch(AppCommand::TogglePlaying);
            ctx.playing
                .store(ctx.app.playback.playing, Ordering::Relaxed);
        }
        _ => {}
    }
    InputResult::Continue
}

fn navigate_code_block(ctx: &mut InputContext, forward: bool) {
    let cache = ctx.app.ui.help_parsed.borrow();
    let Some(parsed) = cache[ctx.app.ui.help_topic].as_ref() else {
        return;
    };
    let count = parsed.code_blocks.len();
    if count == 0 {
        return;
    }
    let next = match ctx.app.ui.help_focused_block {
        Some(cur) if forward => (cur + 1) % count,
        Some(0) if !forward => count - 1,
        Some(cur) if !forward => cur - 1,
        _ if forward => 0,
        _ => count - 1,
    };
    let scroll_to = parsed.code_blocks[next].start_line.saturating_sub(2);
    drop(cache);
    ctx.app.ui.help_focused_block = Some(next);
    ctx.app.ui.help_block_output = None;
    *ctx.app.ui.help_scroll_mut() = scroll_to;
}

fn execute_focused_block(ctx: &mut InputContext) {
    let source = {
        let cache = ctx.app.ui.help_parsed.borrow();
        let Some(parsed) = cache[ctx.app.ui.help_topic].as_ref() else {
            return;
        };
        let idx = ctx.app.ui.help_focused_block.unwrap();
        let Some(block) = parsed.code_blocks.get(idx) else {
            return;
        };
        block.source.clone()
    };
    let cleaned: String = source
        .lines()
        .map(|l| l.split(" => ").next().unwrap_or(l))
        .collect::<Vec<_>>()
        .join("\n");
    let topic = ctx.app.ui.help_topic;
    let block_idx = ctx.app.ui.help_focused_block.expect("block focused in code nav");
    match ctx
        .app
        .execute_script_oneshot(&cleaned, ctx.link, ctx.audio_tx)
    {
        Ok(Some(output)) => {
            ctx.app.ui.flash(&output, 200, FlashKind::Info);
            ctx.app.ui.help_block_output = Some((topic, block_idx, output));
        }
        Ok(None) => ctx.app.ui.flash("Executed", 100, FlashKind::Info),
        Err(e) => ctx
            .app
            .ui
            .flash(&format!("Error: {e}"), 200, FlashKind::Error),
    }
}

fn collapse_help_section(ctx: &mut InputContext) {
    if let Some(s) = ctx.app.ui.help_on_section {
        if ctx.app.ui.help_collapsed.get(s).copied().unwrap_or(false) {
            return;
        }
    }
    let section = match ctx.app.ui.help_on_section {
        Some(s) => s,
        None => docs::section_index_for_topic(ctx.app.ui.help_topic),
    };
    if let Some(v) = ctx.app.ui.help_collapsed.get_mut(section) {
        *v = true;
    }
    ctx.app.ui.help_on_section = Some(section);
    ctx.app.ui.help_focused_block = None;
    ctx.app.ui.help_block_output = None;
}

fn expand_help_section(ctx: &mut InputContext) {
    let Some(section) = ctx.app.ui.help_on_section else {
        return;
    };
    if let Some(v) = ctx.app.ui.help_collapsed.get_mut(section) {
        *v = false;
    }
    ctx.app.ui.help_on_section = None;
    if let Some(first) = docs::first_topic_in_section(section) {
        ctx.app.ui.help_topic = first;
    }
    ctx.app.ui.help_focused_block = None;
    ctx.app.ui.help_block_output = None;
}

fn collapse_dict_section(ctx: &mut InputContext) {
    if let Some(s) = ctx.app.ui.dict_on_section {
        if ctx.app.ui.dict_collapsed.get(s).copied().unwrap_or(false) {
            return;
        }
    }
    let section = match ctx.app.ui.dict_on_section {
        Some(s) => s,
        None => categories::section_index_for_category(ctx.app.ui.dict_category),
    };
    if let Some(v) = ctx.app.ui.dict_collapsed.get_mut(section) {
        *v = true;
    }
    ctx.app.ui.dict_on_section = Some(section);
}

fn expand_dict_section(ctx: &mut InputContext) {
    let Some(section) = ctx.app.ui.dict_on_section else {
        return;
    };
    if let Some(v) = ctx.app.ui.dict_collapsed.get_mut(section) {
        *v = false;
    }
    ctx.app.ui.dict_on_section = None;
    if let Some(first) = categories::first_category_in_section(section) {
        ctx.app.ui.dict_category = first;
    }
}

pub(super) fn handle_dict_page(ctx: &mut InputContext, key: KeyEvent) -> InputResult {
    let ctrl = key.modifiers.contains(KeyModifiers::CONTROL);

    if ctx.app.ui.dict_search_active {
        match key.code {
            KeyCode::Esc => ctx.dispatch(AppCommand::DictClearSearch),
            KeyCode::Enter => ctx.dispatch(AppCommand::DictSearchConfirm),
            KeyCode::Backspace => ctx.dispatch(AppCommand::DictSearchBackspace),
            KeyCode::Char(c) if !ctrl => ctx.dispatch(AppCommand::DictSearchInput(c)),
            _ => {}
        }
        return InputResult::Continue;
    }

    match key.code {
        KeyCode::Char('/') | KeyCode::Char('f') if key.code == KeyCode::Char('/') || ctrl => {
            ctx.dispatch(AppCommand::DictActivateSearch);
        }
        KeyCode::Esc if !ctx.app.ui.dict_search_query.is_empty() => {
            ctx.dispatch(AppCommand::DictClearSearch);
        }
        KeyCode::Tab => ctx.dispatch(AppCommand::DictToggleFocus),
        KeyCode::Left if ctx.app.ui.dict_focus == DictFocus::Categories => {
            collapse_dict_section(ctx);
        }
        KeyCode::Right if ctx.app.ui.dict_focus == DictFocus::Categories => {
            expand_dict_section(ctx);
        }
        KeyCode::Char('j') | KeyCode::Down => match ctx.app.ui.dict_focus {
            DictFocus::Categories => ctx.dispatch(AppCommand::DictNextCategory),
            DictFocus::Words => ctx.dispatch(AppCommand::DictScrollDown(1)),
        },
        KeyCode::Char('k') | KeyCode::Up => match ctx.app.ui.dict_focus {
            DictFocus::Categories => ctx.dispatch(AppCommand::DictPrevCategory),
            DictFocus::Words => ctx.dispatch(AppCommand::DictScrollUp(1)),
        },
        KeyCode::PageDown => ctx.dispatch(AppCommand::DictScrollDown(10)),
        KeyCode::PageUp => ctx.dispatch(AppCommand::DictScrollUp(10)),
        KeyCode::Char('q') if !ctx.app.plugin_mode => {
            ctx.dispatch(AppCommand::OpenModal(Modal::Confirm {
                action: ConfirmAction::Quit,
                selected: false,
            }));
        }
        KeyCode::Char('s') => super::open_save(ctx),
        KeyCode::Char('l') => super::open_load(ctx),
        KeyCode::Char('?') => {
            ctx.dispatch(AppCommand::OpenModal(Modal::KeybindingsHelp { scroll: 0 }));
        }
        KeyCode::Char(' ') if !ctx.app.plugin_mode => {
            ctx.dispatch(AppCommand::TogglePlaying);
            ctx.playing
                .store(ctx.app.playback.playing, Ordering::Relaxed);
        }
        _ => {}
    }
    InputResult::Continue
}