"""
haTerm - v0.1
(c) Sophia Schmidhofer

haTerm is a Terminal Based hafas client, using the ivb endpoint.
Prompt_toolkit (https://github.com/prompt-toolkit/python-prompt-toolkit) will be used to render a terminal user interface (TUI).
The application will provide routing information and station departures/arrivals.

Route planning UI.

Wrapped in a function so it can be launched from `main.py` with a shared
`HafasClient` instance from `backend.py`.

Note: This module is a minimal TUI stub. Many features are not implemented
yet (station lookup, route rendering). Add TODOs where appropriate.
"""

import datetime
from prompt_toolkit import Application, prompt
from prompt_toolkit.buffer import Buffer
from prompt_toolkit.layout.containers import HSplit, VSplit, Window
from prompt_toolkit.formatted_text import HTML
from prompt_toolkit.layout.controls import BufferControl, FormattedTextControl
from prompt_toolkit.layout.layout import Layout
from prompt_toolkit.key_binding import KeyBindings
from prompt_toolkit.shortcuts import yes_no_dialog
import backend


# ── Colour palette ────────────────────────────────────────────────────────────
BLUE_DARK   = "#0d1f3c"   # header / footer background
BLUE_MID    = "#1b4b9a"   # accent / separator
BLUE_LIGHT  = "#add4ff"   # secondary text (clock date, labels)
WHITE       = "#e8f0fe"   # primary text
GREY        = "#4a5568"   # muted text / disabled
PURPLE      = "#a78bfa"   # journey-path dot trail
BG_MAIN     = "#0a0f1e"   # main body background
BG_ROW      = "#111827"   # alternating row tint
# ─────────────────────────────────────────────────────────────────────────────


def run_route_planning(hafas: backend.HafasClient | None = None):
    """Run the route planning TUI.

    Parameters:
    - hafas: optional shared HafasClient instance. If omitted, a new one is
      created. Prefer passing the shared client from `main.py`.
    """
    if hafas is None:
        hafas = backend.HafasClient()

    kb = KeyBindings()

    # ── Input phase (before TUI) ──────────────────────────────────────────────
    start_input = prompt("Von:  ")
    end_input   = prompt("Nach: ")

    station1 = hafas.getStationNames(start_input)
    station2 = hafas.getStationNames(end_input)

    # Resolved station names (fall back to raw input if lookup fails)
    start_name = station1[0][0] if station1 else start_input
    end_name   = station2[0][0] if station2 else end_input

    # TODO: fetch actual departure / arrival times from `hafas`.
    # TODO: fetch actual journey duration from `hafas`.

    # ── Buffers ───────────────────────────────────────────────────────────────
    start_buf = Buffer()
    start_buf.text = start_name

    etd_buf = Buffer()
    etd_buf.text = "──:──"          # TODO: real departure time

    end_buf = Buffer()
    end_buf.text = end_name

    eta_buf = Buffer()
    eta_buf.text = "──:──"          # TODO: real arrival time

    # ── Dynamic text helpers ──────────────────────────────────────────────────
    def clock_text():
        now = datetime.datetime.now()
        return HTML(
            f'<style bg="{BLUE_DARK}" fg="{WHITE}">  🕐  <b>{now.strftime("%H:%M:%S")}</b>  </style>'
            f'<style bg="{BLUE_DARK}" fg="{BLUE_LIGHT}">│  {now.strftime("%A, %d. %B %Y")}  </style>'
        )

    def header_text():
        return HTML(
            f'<style bg="{BLUE_DARK}" fg="{WHITE}">  <b>haTerm</b> </style>'
            f'<style bg="{BLUE_DARK}" fg="{BLUE_LIGHT}"> · Routenplanung  </style>'
        )

    def hint_text():
        return HTML(
            f'<style bg="{BLUE_DARK}" fg="{GREY}">  Ctrl+E</style>'
            f'<style bg="{BLUE_DARK}" fg="{BLUE_LIGHT}"> Beenden  </style>'
        )

    def label(text):
        """Left-aligned label in the narrow column."""
        return FormattedTextControl(
            HTML(f'<style fg="{BLUE_LIGHT}">  {text}  </style>')
        )

    def sublabel(text):
        """Muted sublabel for times."""
        return FormattedTextControl(
            HTML(f'<style fg="{GREY}">  {text}  </style>')
        )

    # ── Layout ────────────────────────────────────────────────────────────────
    LABEL_W = 6   # width of the label column

    root_container = HSplit([

        # ── Header bar ────────────────────────────────────────────────────────
        Window(
            height=1,
            content=FormattedTextControl(header_text),
            style=f"bg:{BLUE_DARK}",
        ),
        Window(height=1, char="─", style=f"fg:{BLUE_MID} bg:{BG_MAIN}"),

        # ── Spacer ────────────────────────────────────────────────────────────
        Window(height=1, char=" ", style=f"bg:{BG_MAIN}"),

        # ── Departure row ─────────────────────────────────────────────────────
        VSplit([
            Window(width=LABEL_W, content=label("Von"), style=f"bg:{BG_ROW}"),
            Window(
                content=BufferControl(buffer=start_buf, focusable=True),
                style=f"fg:{WHITE} bg:{BG_ROW}",
            ),
        ], height=1),

        VSplit([
            Window(width=LABEL_W, content=sublabel("Ab"), style=f"bg:{BG_ROW}"),
            Window(
                content=BufferControl(buffer=etd_buf, focusable=False),
                style=f"fg:{GREY} bg:{BG_ROW}",
            ),
        ], height=1),

        # ── Journey path (dot trail) ───────────────────────────────────────────
        Window(height=1, char=" ", style=f"bg:{BG_MAIN}"),
        Window(
            height=1,
            content=FormattedTextControl(
                HTML(f'<style fg="{PURPLE}">  {"·  " * 18}</style>')
            ),
            style=f"bg:{BG_MAIN}",
        ),
        Window(height=1, char=" ", style=f"bg:{BG_MAIN}"),

        # ── Arrival row ───────────────────────────────────────────────────────
        VSplit([
            Window(width=LABEL_W, content=label("Nach"), style=f"bg:{BG_ROW}"),
            Window(
                content=BufferControl(buffer=end_buf, focusable=True),
                style=f"fg:{WHITE} bg:{BG_ROW}",
            ),
        ], height=1),

        VSplit([
            Window(width=LABEL_W, content=sublabel("An"), style=f"bg:{BG_ROW}"),
            Window(
                content=BufferControl(buffer=eta_buf, focusable=False),
                style=f"fg:{GREY} bg:{BG_ROW}",
            ),
        ], height=1),

        # ── Spacer ────────────────────────────────────────────────────────────
        Window(char=" ", style=f"bg:{BG_MAIN}"),

        # ── Clock bar ─────────────────────────────────────────────────────────
        Window(height=1, char="─", style=f"fg:{BLUE_MID} bg:{BG_MAIN}"),
        Window(
            content=FormattedTextControl(clock_text),
            height=1,
            style=f"bg:{BLUE_DARK}",
        ),

        # ── Keybinding hint bar ───────────────────────────────────────────────
        Window(
            height=1,
            content=FormattedTextControl(hint_text),
            style=f"bg:{BLUE_DARK}",
        ),
    ])

    # ── Key bindings ──────────────────────────────────────────────────────────
    @kb.add("c-e")
    def _(event):
        confirmed = yes_no_dialog(
            title="Programm beenden",
            text="haTerm schließen?",
        ).run()
        if confirmed:
            event.app.exit()

    # ── Run ───────────────────────────────────────────────────────────────────
    layout = Layout(root_container)
    app = Application(
        layout=layout,
        key_bindings=kb,
        full_screen=True,
        refresh_interval=1.0,   # keeps the clock ticking
        mouse_support=False,
    )

    try:
        app.run()
    except KeyboardInterrupt:
        return