local input = require("lib-core.input")
local git   = require("lib-core.git")
local depf  = require("lib-management.dep-fetcher")
-- fsm.lua lives in this module's dir; engine_lua_lib's searcher only
-- resolves declared lib-deps, so multi-file modules use dofile +
-- engine.module.dir_of.
local MODULE_DIR = engine.module.dir_of("lib-management.launcher")
local fsm           = dofile(MODULE_DIR .. "/fsm.lua")
local manifest_loader = dofile(MODULE_DIR .. "/manifest_loader.lua")

local function require_panel(name)
    return dofile(MODULE_DIR .. "/panels/" .. name .. ".lua")
end

local list_panel   = require_panel("list")
local detail_panel = require_panel("detail")

local STATE_LIST, STATE_QUIT, EXIT = fsm.STATE_LIST, fsm.STATE_QUIT_CONFIRM, fsm.EXIT
local state = STATE_LIST

local ctx_panels     = nil   -- built in init(); shared state for both panels
local quit_buttons   = {}    -- {yes = rect, no = rect}
local screen_w, screen_h
local gitea_base     = nil   -- resolved in init() from engine.config

-- CI-conditional self-exit (matches spine-prototype's pattern).
-- Interactive runs (no SPOREL_CI=1) loop until ESC or quit-confirm.
local frames = 0
local CI_FRAMES = 60

local TITLE        = "Sporel Launcher"
local QUIT_PROMPT  = "Sporel beenden?"
local YES_LABEL    = "Ja"
local NO_LABEL     = "Nein"
local EMPTY_LABEL  = "Keine Module installiert."

local FONT_TITLE   = 28
local FONT_BUTTON  = 20
local PAD_X        = 16
local PAD_Y        = 8

local COLOR_BG     = 0x202020FF
local COLOR_BTN    = 0x404040FF
local COLOR_HOVER  = 0x606060FF
local COLOR_TEXT   = 0xE0E0E0FF
local COLOR_DIM    = 0x000000B4
local COLOR_MODAL  = 0x303030FF

local hit = engine.spatial.aabb_contains_point

-- ----- helpers -------------------------------------------------------

-- Compare semver-ish "vX.Y.Z" strings. Returns true if a > b.
local function compare_versions(a, b)
    local a_maj, a_min, a_pat = a:match("v?(%d+)%.(%d+)%.(%d+)")
    local b_maj, b_min, b_pat = b:match("v?(%d+)%.(%d+)%.(%d+)")
    if not a_maj or not b_maj then return false end
    local av = { tonumber(a_maj), tonumber(a_min), tonumber(a_pat) }
    local bv = { tonumber(b_maj), tonumber(b_min), tonumber(b_pat) }
    for i = 1, 3 do
        if av[i] > bv[i] then return true end
        if av[i] < bv[i] then return false end
    end
    return false
end

local function module_repo_url(module_id)
    return gitea_base .. "/sporel-module-" .. module_id .. ".git"
end

-- After a successful git.checkout on a module dir, reload its manifest
-- to surface the new version in the UI. Uses dep-fetcher's pure-Lua
-- JSON decoder so we don't add a new engine.json binding for one site.
local function refresh_module_version(m)
    local path = engine.install_root() .. "/modules/" .. m.id
        .. "/manifest.module"
    local f = io.open(path, "rb")
    if not f then return end
    local content = f:read("*a"); f:close()
    local data = depf._json_decode(content)
    if data and data.version then m.version = data.version end
end

local function start_update_check(m)
    if not gitea_base then return end
    local url = module_repo_url(m.id)
    local handle = git.start_ls_remote_tags(url)
    m.status.update_check_handle = handle
    m.status.update_check_result = "pending"
    m.status.update_latest_tag   = nil
end

-- Result poll: success -> compare highest vX.Y.Z tag against m.version.
-- Error kinds from lib-core.git v0.2.0: "auth-required" | "not-found" |
-- "network" | "other". "not-found" → local-only marker; everything else
-- folds into a generic "fail" with the kind preserved for tooltip text.
local function consume_update_check(m)
    local result = git.take_result(m.status.update_check_handle)
    m.status.update_check_handle = nil
    if not result or result.error then
        local kind = result and result.kind or "other"
        if kind == "not-found" then
            m.status.update_check_result = "local-only"
        else
            m.status.update_check_result = "fail"
            m.status.update_check_fail_kind = kind
        end
        return
    end
    local latest = nil
    for _, tag in ipairs(result.tags or {}) do
        if tag:match("^v%d+%.%d+%.%d+$") then
            if not latest or compare_versions(tag, latest) then
                latest = tag
            end
        end
    end
    if latest and compare_versions(latest, "v" .. m.version) then
        m.status.update_check_result = "available"
        m.status.update_latest_tag   = latest
    else
        m.status.update_check_result = "no-update"
    end
end

-- Composes a per-dep status list keyed by lib_id from the dep-fetcher
-- result's `errors` and `warnings` arrays. Each input dep entry is
-- `{id, version}` (from manifest.module::deps[]); each output entry
-- adds `status = "ok" | "warn" | "error"`. Load-order preserved
-- (L-Q6: no re-sort).
local function compose_dep_status_list(result, module_deps)
    local out = {}
    local err_ids, warn_ids = {}, {}
    for _, e in ipairs(result.errors or {}) do
        if e.lib_id then err_ids[e.lib_id] = true end
    end
    for _, w in ipairs(result.warnings or {}) do
        if w.lib_id then warn_ids[w.lib_id] = true end
    end
    for _, c in ipairs(result.conflicts or {}) do
        if c.lib_id then err_ids[c.lib_id] = true end
    end
    for _, d in ipairs(module_deps) do
        local status = "ok"
        if err_ids[d.id] then status = "error"
        elseif warn_ids[d.id] then status = "warn"
        end
        out[#out + 1] = { id = d.id, version = d.version, status = status }
    end
    return out
end

-- Derives a roll-up kind ("ok" | "warn" | "error") from the dep-fetcher
-- result. Drives the list-panel's bg-tint cue via ctx.list_tint.
local function derive_result_kind(result)
    if not result.ok then return "error" end
    if (result.warnings and #result.warnings > 0) then return "warn" end
    return "ok"
end

-- Lazy: only re-check dep-fetcher when the consumer flow asks for it
-- (init + after-update). Heavy-lift in init() is acceptable per the
-- plan; an async dep-check is future work.
local function run_dep_check(m)
    local ok, result = pcall(depf.ensure_for_module, m.id)
    if not (ok and type(result) == "table") then
        result = {
            ok = false, conflicts = {}, warnings = {},
            errors = {{ lib_id = "<launcher>", kind = "internal",
                        message = tostring(result) }},
            closure = {},
        }
    end
    result.deps = compose_dep_status_list(result, m._raw_deps or {})
    result.kind = derive_result_kind(result)
    m.status.dep_check_result = result
end

-- ----- lifecycle -----------------------------------------------------

function init(ctx)
    screen_w, screen_h = engine.window.size()
    gitea_base = engine.config("gitea_base")
                 or "https://git.davoryn.de/sporel"

    -- Slice 7.1: override lib-core.git's token (defaulted from
    -- SPOREL_GITEA_TOKEN env at lib_init) with the engine.json layer
    -- value if the user-data config sets gitea_token. Allows users to
    -- persist their Gitea PAT in %APPDATA%/Sporel/engine.json instead
    -- of carrying an env var around.
    local cfg_token = engine.config("gitea_token")
    if cfg_token and cfg_token ~= "" and type(git.set_token) == "function" then
        git.set_token(cfg_token)
    end

    ctx_panels = {
        -- Persistent UI context, threaded through the panels.
        module_entries     = {},       -- filled below from engine.module.list
        news_entry         = { title = "News", body_path = "news.md" },
        selected_entry     = nil,
        scroll_y           = 0,
        list_tint          = nil,      -- nil | "warn" | "error" — set in L.4
        list_panel_rect    = nil,      -- set below from window size
        detail_panel_rect  = nil,
        bg_texture         = nil,      -- L.10 loads it
        default_teaser_texture = nil,  -- L.10 loads it
        t                  = function(k) return k end,  -- L.8 swaps in real t()
        modal_open         = nil,      -- L.7 sets to "quit" | "conflict"
        carousel_state     = {},       -- per-module-id state, L.5 populates
        manifest_cache     = {},       -- L.3 populates
        launcher_dir       = MODULE_DIR, -- L.4: detail.lua dofiles markdown.lua via this
    }

    -- Window split: 1/3 list, 2/3 detail. Margin 12px between panels.
    local SW, SH = screen_w, screen_h
    ctx_panels.list_panel_rect   = { x = 0,           y = 0, w = SW / 3,         h = SH }
    ctx_panels.detail_panel_rect = { x = SW / 3 + 12, y = 0, w = SW * 2/3 - 12,  h = SH }

    local raw_list = engine.module.list() or {}
    for i, m in ipairs(raw_list) do
        ctx_panels.module_entries[i] = {
            id      = m.id,
            version = m.version,
            name    = m.name or m.id,
            summary = nil,     -- L.3 fills from manifest.launcher.md
            rect    = nil,
            status  = {
                update_check_handle = nil,
                update_check_result = nil,
                update_check_fail_kind = nil,
                update_latest_tag   = nil,
                dep_check_result    = nil,
                spinner_rect = nil, warn_rect = nil,
                badge_rect   = nil, error_rect = nil,
                local_rect   = nil,
            },
        }
    end

    -- L.3: load + cache manifest.launcher.md for each module. Missing
    -- files degrade gracefully (meta._missing=true) so the list-panel
    -- falls back to name/id.
    for _, entry in ipairs(ctx_panels.module_entries) do
        local meta, blocks = manifest_loader.load_for(entry.id)
        ctx_panels.manifest_cache[entry.id] = { meta = meta, blocks = blocks }
        entry.summary = meta.summary

        -- L.4: also surface manifest.module::deps[] verbatim so the
        -- detail-panel can render per-dep status glyphs in load order
        -- (no re-sort, per L-Q6).
        local raw, _ = engine.module.read_file(entry.id, "manifest.module")
        if raw then
            local data = depf._json_decode(raw)
            if data and data.deps then entry._raw_deps = data.deps end
        end
    end

    local wy, hy = engine.render.measure_text(YES_LABEL, FONT_BUTTON)
    local wn, hn = engine.render.measure_text(NO_LABEL,  FONT_BUTTON)
    local qbtn_w = math.max(wy, wn) + 2 * PAD_X
    local qbtn_h = math.max(hy, hn) + 2 * PAD_Y
    local total_w = 2 * qbtn_w + 24
    quit_buttons.yes = { x = (screen_w - total_w) / 2,                 y = screen_h / 2 + 24, w = qbtn_w, h = qbtn_h }
    quit_buttons.no  = { x = (screen_w - total_w) / 2 + qbtn_w + 24,   y = screen_h / 2 + 24, w = qbtn_w, h = qbtn_h }

    input.bind("ui_click",   { "mouse_left" })
    input.bind("ui_back",    { "escape" })
    input.bind("ui_confirm", { "enter" })

    -- Kick off async update-checks (one ls-remote per module). Network
    -- calls; gated off in CI to keep milestone-check offline.
    if os.getenv("SPOREL_CI") ~= "1" then
        for _, m in ipairs(ctx_panels.module_entries) do start_update_check(m) end
    end

    -- Pre-emptive dep-check per module. Sync today (plan §7.6 future
    -- work: async). In a packaged install with closures already
    -- present, this is filesystem-only and fast; the slow path
    -- (missing libs → clone) only fires on first launch / new module.
    for _, m in ipairs(ctx_panels.module_entries) do run_dep_check(m) end

    engine.print(string.format("launcher: init ok, modules=%d",
                               #ctx_panels.module_entries))
end

function update(ctx, dt)
    frames = frames + 1
    if os.getenv("SPOREL_CI") == "1" and frames >= CI_FRAMES then
        engine.exit(0)
        return
    end

    -- Poll async update-check handles.
    for _, m in ipairs(ctx_panels.module_entries) do
        local h = m.status.update_check_handle
        if h and git.is_done(h) then
            consume_update_check(m)
        end
    end

    local mx, my = engine.input.get_mouse_pos()

    if state == STATE_LIST then
        if input.was_action_pressed("ui_back") then
            state = fsm.next(state, "esc")
        elseif input.was_action_pressed("ui_click") then
            if not list_panel.handle_click(ctx_panels, mx, my) then
                detail_panel.handle_click(ctx_panels, mx, my)
            end
        end
    elseif state == STATE_QUIT then
        if input.was_action_pressed("ui_back") then
            state = fsm.next(state, "esc")
        elseif input.was_action_pressed("ui_confirm") then
            engine.exit(0); return
        elseif input.was_action_pressed("ui_click") then
            if hit(quit_buttons.yes, mx, my) then
                engine.exit(0); return
            elseif hit(quit_buttons.no, mx, my) then
                state = fsm.next(state, "click_no")
            end
        end
    end
end

function render(ctx)
    local mx, my = engine.input.get_mouse_pos()

    engine.render.clear_color(COLOR_BG)

    list_panel.render(ctx_panels)
    detail_panel.render(ctx_panels)

    if state == STATE_QUIT then
        engine.render.draw_rect(0, 0, screen_w, screen_h, COLOR_DIM)
        local modal_w, modal_h = 360, 140
        engine.render.draw_rect((screen_w - modal_w) / 2,
                                (screen_h - modal_h) / 2,
                                modal_w, modal_h, COLOR_MODAL)
        local pw = engine.render.measure_text(QUIT_PROMPT, FONT_BUTTON)
        engine.render.draw_text(QUIT_PROMPT, (screen_w - pw) / 2,
                                screen_h / 2 - 24, FONT_BUTTON, COLOR_TEXT)

        for _, key in ipairs({ "yes", "no" }) do
            local b = quit_buttons[key]
            local color = hit(b, mx, my) and COLOR_HOVER or COLOR_BTN
            engine.render.draw_rect(b.x, b.y, b.w, b.h, color)
            local label = (key == "yes") and YES_LABEL or NO_LABEL
            local lw = engine.render.measure_text(label, FONT_BUTTON)
            engine.render.draw_text(label, b.x + (b.w - lw) / 2,
                                    b.y + PAD_Y, FONT_BUTTON, COLOR_TEXT)
        end
    end
end

function cleanup(ctx)
    engine.print("launcher: cleanup")
end