local M = {}

local PADDING       = 24
local COLOR_BG      = 0x282828FF
local COLOR_TEXT    = 0xE0E0E0FF
local COLOR_DIM     = 0xA0A0A0FF
local COLOR_OK      = 0x80C080FF
local COLOR_WARN    = 0xE0C040FF
local COLOR_ERR     = 0xE05040FF
local FONT_TITLE    = 28
local FONT_SUB      = 16
local FONT_BODY     = 14
local FONT_DEP      = 14

local md  -- lazy-loaded markdown renderer

local function ensure_md(launcher_dir)
    if not md then md = dofile(launcher_dir .. "/markdown.lua") end
end

local function status_glyph(dep_status)
    if dep_status == "ok"    then return "OK",   COLOR_OK   end
    if dep_status == "warn"  then return "WARN", COLOR_WARN end
    if dep_status == "error" then return "ERR",  COLOR_ERR  end
    return "?", COLOR_DIM
end

local function find_entry(ctx, id)
    if id == "news" then return nil end
    for _, e in ipairs(ctx.module_entries) do
        if e.id == id then return e end
    end
    return nil
end

function M.render(ctx)
    local p = ctx.detail_panel_rect
    engine.render.draw_rect(p.x, p.y, p.w, p.h, COLOR_BG)

    if not ctx.selected_entry then
        if ctx.bg_texture then engine.render.draw_texture(ctx.bg_texture, p.x, p.y) end
        local hint = ctx.t("empty_hint")
        local w, h = engine.render.measure_text(hint, FONT_BODY)
        engine.render.draw_text(hint, p.x + (p.w - w) / 2, p.y + (p.h - h) / 2,
                                FONT_BODY, COLOR_DIM)
        return
    end

    -- News: render news.md.
    if ctx.selected_entry == "news" then
        ensure_md(ctx.launcher_dir)
        local body = ctx.news_body_blocks or {}
        md.render(body, p.x + PADDING, p.y + PADDING, p.w - 2 * PADDING, nil)
        return
    end

    local entry = find_entry(ctx, ctx.selected_entry)
    if not entry then return end
    local mc = ctx.manifest_cache[entry.id] or { meta = {}, blocks = {} }

    -- Carousel hero placeholder: L.5 swaps this in. For now: a strip.
    local hero_h = 160
    if ctx.carousel_state[entry.id] and ctx.carousel_mod then
        -- L.5 implements this; render call lands later.
    else
        engine.render.draw_rect(p.x, p.y, p.w, hero_h, 0x404040FF)
    end

    local cur_y = p.y + hero_h + PADDING
    -- Title row.
    local title = entry.summary or entry.name or entry.id
    engine.render.draw_text(title, p.x + PADDING, cur_y, FONT_TITLE, COLOR_TEXT)
    local _, title_h = engine.render.measure_text(title, FONT_TITLE)
    -- Version + author right-aligned.
    local sub = string.format("v%s  %s", entry.version, mc.meta.author or "")
    local sub_w, _ = engine.render.measure_text(sub, FONT_SUB)
    engine.render.draw_text(sub, p.x + p.w - PADDING - sub_w, cur_y + 6,
                            FONT_SUB, COLOR_DIM)
    cur_y = cur_y + title_h + 12

    -- Description (rendered MD).
    ensure_md(ctx.launcher_dir)
    cur_y = md.render(mc.blocks, p.x + PADDING, cur_y,
                      p.w - 2 * PADDING, entry.id)

    cur_y = cur_y + 12

    -- Dep list — load-order from manifest.module per L-Q6.
    local r = entry.status.dep_check_result
    local dep_count = (r and r.deps and #r.deps) or 0
    engine.render.draw_text(
        string.format("%s (%d)", ctx.t("dependencies"), dep_count),
        p.x + PADDING, cur_y, FONT_SUB, COLOR_TEXT)
    cur_y = cur_y + 24

    if r and r.deps then
        for _, d in ipairs(r.deps) do
            local glyph, col = status_glyph(d.status)
            engine.render.draw_text(glyph, p.x + PADDING, cur_y, FONT_DEP, col)
            engine.render.draw_text(string.format("%s  %s", d.id, d.version),
                p.x + PADDING + 40, cur_y, FONT_DEP, COLOR_TEXT)
            cur_y = cur_y + 20
        end
    end

    -- Whole-list tint hint: bubble up to ctx.list_tint so panels/list.lua picks it up.
    if r and r.kind == "error" then ctx.list_tint = "error"
    elseif r and r.kind == "warn" then ctx.list_tint = "warn"
    end
end

function M.handle_click(ctx, mx, my)
    -- L.5/L.7 add carousel-arrow + launch-button hit-tests.
    return false
end

return M