"""Tree-style display of MPEG-2 PSI structure (PAT/PMT).

Renders a hierarchical view of the Program Association Table and its
child Program Map Tables using Rich markup inside a Static widget.
Shows transport stream ID, program numbers, PMT PIDs, PCR PIDs,
and elementary stream types with their PIDs.
"""

from textual.widget import Widget
from textual.widgets import Static
from textual.app import ComposeResult


class PsiTree(Widget):
    """Hierarchical PAT/PMT display for transport stream program structure."""

    DEFAULT_CSS = """
    PsiTree {
        height: 1fr;
        min-height: 8;
        background: #0e1420;
        border: round #1a2a3a;
        padding: 1;
        overflow-y: auto;
    }
    """

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self._pat: dict | None = None
        self._pmts: dict[int, dict] = {}

    def compose(self) -> ComposeResult:
        yield Static(
            "[#506878]Waiting for PSI data...[/]", id="psi-content"
        )

    def update_pat(self, pat: dict) -> None:
        """Update the Program Association Table and redraw."""
        self._pat = pat
        self._refresh()

    def update_pmt(self, pmt_pid: int, pmt: dict) -> None:
        """Update a Program Map Table and redraw."""
        self._pmts[pmt_pid] = pmt
        self._refresh()

    def clear_tree(self) -> None:
        """Reset all PSI state and show placeholder."""
        self._pat = None
        self._pmts.clear()
        if self.is_mounted:
            self.query_one("#psi-content", Static).update(
                "[#506878]Waiting for PSI data...[/]"
            )

    def _refresh(self) -> None:
        """Rebuild the tree markup from current PAT/PMT data."""
        if not self.is_mounted:
            return

        lines: list[str] = []

        if self._pat:
            tsid = self._pat.get("transport_stream_id", 0)
            ver = self._pat.get("version", 0)
            lines.append(
                f"[bold #00d4aa]PAT[/] [#506878]TSID=0x{tsid:04X} v{ver}[/]"
            )

            programs = self._pat.get("programs", {})
            # Separate NIT (program 0) from real programs
            real_progs = {k: v for k, v in programs.items() if k != 0}

            for prog_num, pmt_pid in sorted(programs.items()):
                if prog_num == 0:
                    lines.append(
                        f"  [#7090a8]\u251c\u2500[/] [#506878]NIT[/] "
                        f"PID=0x{pmt_pid:04X}"
                    )
                else:
                    is_last = prog_num == max(real_progs.keys())
                    prefix = "\u2514\u2500" if is_last else "\u251c\u2500"
                    lines.append(
                        f"  [#7090a8]{prefix}[/] "
                        f"[bold #c8d0d8]Program {prog_num}[/] "
                        f"PMT=0x{pmt_pid:04X}"
                    )
                    # Expand PMT details if available
                    if pmt_pid in self._pmts:
                        pmt = self._pmts[pmt_pid]
                        pcr_pid = pmt.get("pcr_pid", 0)
                        indent = "   " if is_last else "\u2502  "
                        lines.append(
                            f"  {indent} [#506878]PCR PID=0x{pcr_pid:04X}[/]"
                        )
                        streams = pmt.get("streams", [])
                        for j, s in enumerate(streams):
                            s_last = j == len(streams) - 1
                            s_prefix = "\u2514\u2500" if s_last else "\u251c\u2500"
                            type_name = s.get("type_name", "Unknown")
                            epid = s.get("elementary_pid", 0)
                            lines.append(
                                f"  {indent} [#7090a8]{s_prefix}[/] "
                                f"[#c8d0d8]{type_name}[/] "
                                f"PID=0x{epid:04X}"
                            )
        else:
            lines.append("[#506878]No PAT received yet[/]")

        self.query_one("#psi-content", Static).update("\n".join(lines))