"""The Manage Kits dialog: what the app pins, what Sedona home offers, and repinning.

The table answers two questions per kit — which build the app is pinned to, and which
builds exist — and the Action column is where a different build is chosen. Nothing is
written to the file until one of the buttons is pressed, so the whole table can be set up
first and reviewed as a batch.

Rows come in three groups, in this order: kits the app needs — named by a component or
depended on by a kit that is — then kits the schema declares without needing, then
everything else installed in Sedona home.

The tick in the first column means "the schema declares this kit". A kit the app needs is
ticked and greyed, because removing it would stop the app running; one that is merely
declared can be unticked, which turns its Action into REMOVE. An installed kit that is not
declared starts unticked, and ticking it adds it at its newest build.
"""

import tkinter as tk
from tkinter import messagebox, ttk

import app_state
import palette
import sax_file

NOT_DECLARED = "—"          # em dash, for a column with nothing to report
NO_CHECKSUM = "(no checksum)"
REMOVE_ACTION = "REMOVE from app"

SECTION_TAG = "section"

CHECKBOX_SIZE = 13

# The tick, as filled 2x2 blocks: a short down-stroke into a long up-stroke.
TICK_BLOCKS = [
    (2, 5), (3, 6), (4, 7), (5, 6), (6, 5), (7, 4), (8, 3), (9, 2),
]


def make_checkbox_image(checked, enabled):
    """A checkbox drawn pixel by pixel, so a locked tick can be greyed out.

    Tk has no disabled state for a cell, and a row tag would grey the whole row including
    an Action the user can still change — so the box itself carries the distinction.
    """
    image = tk.PhotoImage(width=CHECKBOX_SIZE, height=CHECKBOX_SIZE)

    face = "#ffffff" if enabled else "#f0f0f0"
    border = "#555555" if enabled else "#a8a8a8"
    ink = "#1a1a1a" if enabled else "#909090"

    image.put(face, to=(0, 0, CHECKBOX_SIZE, CHECKBOX_SIZE))
    image.put(border, to=(0, 0, CHECKBOX_SIZE, 1))
    image.put(border, to=(0, CHECKBOX_SIZE - 1, CHECKBOX_SIZE, CHECKBOX_SIZE))
    image.put(border, to=(0, 0, 1, CHECKBOX_SIZE))
    image.put(border, to=(CHECKBOX_SIZE - 1, 0, CHECKBOX_SIZE, CHECKBOX_SIZE))

    if checked:
        for x, y in TICK_BLOCKS:
            image.put(ink, to=(x, y, x + 2, y + 2))

    return image


def build_label(version, checksum):
    """How a build is named in a sentence: its version, or its checksum when it has none."""
    return version if version else f"checksum {checksum}"


def column_label(version, checksum):
    """How a build is named in the Installed and Latest columns, which are narrow."""
    return version if version else checksum


def action_options(kit_name, current_checksum, is_declared, builds):
    """The Action dropdown for one kit: (label, checksum to apply) pairs, no-op first.

    The no-op comes first so a row does nothing until the user picks something, and the
    remaining entries read as upgrade or downgrade relative to the pinned build — which is
    what makes the column scannable when a kit ships thirty builds.
    """
    installed_version = None
    for version, checksum in builds:
        if checksum == current_checksum:
            installed_version = version
            break

    if not is_declared:
        options = [("Not in schema", None)]
    elif current_checksum is None:
        options = [("Keep with no checksum", None)]
    elif installed_version is None:
        # The file pins a build this machine does not hold, so there is nothing to name it
        # by and no way to tell whether the other builds are newer or older than it.
        options = [(f"Keep at checksum {current_checksum}", None)]
    else:
        options = [(f"Keep at {build_label(installed_version, current_checksum)}", None)]

    installed_rank = palette.version_sort_key(installed_version) if installed_version else None

    for version, checksum in builds:
        if is_declared and checksum == current_checksum:
            continue

        label = build_label(version, checksum)
        if not is_declared:
            verb = "Add at"
        elif installed_rank is None or not version:
            verb = "Set to"
        elif palette.version_sort_key(version) > installed_rank:
            verb = "Upgrade to"
        elif palette.version_sort_key(version) < installed_rank:
            verb = "Downgrade to"
        else:
            verb = "Set to"
        options.append((f"{verb} {label}", checksum))

    return options


def collect_rows():
    """Every kit worth listing, as row dicts in the order they should appear.

    A row carries what the table paints and what the buttons act on, so the dialog never
    has to re-derive a kit's state from the DOM while it is open.
    """
    declared = sax_file.schema_kit_checksums()
    declared_names = [name for name, _ in declared]
    required = sax_file.required_kit_names()

    installed = palette.list_kits()
    # A kit the schema declares but Sedona home does not hold still gets a row: it is the
    # clearest place to see that the file points at something missing.
    others = [name for name in installed if name not in declared_names]

    groups = [
        ("Installed kits", [
            (name, checksum) for name, checksum in declared if name in required
        ]),
        ("Installed but not used kits", [
            (name, checksum) for name, checksum in declared if name not in required
        ]),
        ("Kits to be installed", [(name, None) for name in others]),
    ]

    rows = []
    for title, entries in groups:
        if not entries:
            continue
        rows.append({"section": title})
        for name, checksum in entries:
            builds = palette.kit_builds(name)
            latest = builds[0] if builds else None
            is_declared = name in declared_names
            options = action_options(name, checksum, is_declared, builds)

            if not is_declared:
                installed_text = NOT_DECLARED
            elif checksum is None:
                installed_text = NO_CHECKSUM
            else:
                installed_text = column_label(
                    next((v for v, c in builds if c == checksum), ""), checksum
                )

            rows.append({
                "kit": name,
                "declared": is_declared,
                "required": name in required,
                "checksum": checksum,
                "builds": builds,
                "latest": latest,
                "installed_text": installed_text,
                "latest_text": column_label(*latest) if latest else NOT_DECLARED,
                "options": options,
                "choice": 0,
                # The tick reflects the file as it stands: declared kits start ticked.
                "checked": is_declared,
            })
    return rows


def describe_changes(changes):
    """The applied-changes report, one kit per line, old build to new."""
    lines = []
    for kit_name, old_checksum, new_checksum in changes:
        old_label = (
            build_label(palette.version_for_checksum(kit_name, old_checksum), old_checksum)
            if old_checksum else None
        )

        if new_checksum is None:
            was = f" (was {old_label})" if old_label else ""
            lines.append(f"    • {kit_name}: removed from the schema{was}")
            continue

        new_label = build_label(
            palette.version_for_checksum(kit_name, new_checksum), new_checksum
        )
        if old_checksum is None:
            lines.append(f"    • {kit_name}: added at {new_label}")
        else:
            lines.append(f"    • {kit_name}: {old_label} → {new_label}")
    return "\n".join(lines)


class KitsPanel:
    """The kit table, built as an embedded panel in the editor pane."""

    def __init__(self, parent, on_applied, on_close):
        self.on_applied = on_applied
        self.on_close = on_close

        self.frame = ttk.Frame(parent, padding=10)

        COLUMNS = ("name", "installed", "latest", "action")
        self.table = ttk.Treeview(
            self.frame, columns=COLUMNS, show="tree headings", selectmode="browse",
        )
        self.table.heading("#0", text="")
        self.table.column("#0", width=32, minwidth=32, stretch=False, anchor="center")
        for column, heading, width, stretch, anchor in [
            ("name", "Kit name", 200, True, "w"),
            ("installed", "Installed", 105, False, "w"),
            ("latest", "Latest", 105, False, "w"),
            ("action", "Action", 300, False, "w"),
        ]:
            self.table.heading(column, text=heading, anchor=anchor)
            self.table.column(column, width=width, anchor=anchor, stretch=stretch)

        scrollbar = ttk.Scrollbar(self.frame, orient=tk.VERTICAL, command=self.table.yview)
        self.table.configure(yscrollcommand=scrollbar.set)
        scrollbar.pack(side=tk.RIGHT, fill=tk.Y)
        self.table.pack(fill=tk.BOTH, expand=True)

        self.table.tag_configure(SECTION_TAG, background="#dcdcdc")

        self.boxes = {
            (True, True): make_checkbox_image(True, True),
            (False, True): make_checkbox_image(False, True),
            (True, False): make_checkbox_image(True, False),
            (False, False): make_checkbox_image(False, False),
        }

        hint = ttk.Label(
            self.frame,
            text="A tick means the schema declares the kit. Grey ticks are needed by the app "
                 "and cannot be removed; untick another to remove it. Click the Action cell to "
                 "choose a build. Nothing reaches the file until you save it.",
            foreground="#666666",
            wraplength=780,
        )
        hint.pack(anchor="w", pady=(8, 0))

        button_row = ttk.Frame(self.frame)
        button_row.pack(fill=tk.X, pady=(10, 0))

        ttk.Button(
            button_row, text="Upgrade all kits to latest version", command=self._upgrade_all,
        ).pack(side=tk.LEFT)
        ttk.Button(
            button_row, text="Update kits", command=self._update_marked,
        ).pack(side=tk.LEFT, padx=6)
        ttk.Button(button_row, text="Close", command=self.close).pack(side=tk.RIGHT)

        self.rows = []
        self.row_by_item = {}
        self._editor_widget = None

        self.table.bind("<Button-1>", self._on_click)
        self.table.bind("<MouseWheel>", lambda _e: self._close_editor(), add="+")
        self.table.bind("<Configure>", lambda _e: self._close_editor(), add="+")

        self._rebuild_table()

    def close(self):
        if self.on_close is not None:
            self.on_close()

    def destroy(self):
        self._close_editor()
        self.frame.destroy()

    def _close_editor(self):
        if self._editor_widget is not None:
            self._editor_widget.destroy()
            self._editor_widget = None

    def _action_text(self, row):
        if row["declared"] and not row["checked"]:
            return REMOVE_ACTION
        return row["options"][row["choice"]][0]

    def _row_values(self, row):
        return (row["kit"], row["installed_text"], row["latest_text"], self._action_text(row))

    def _row_image(self, row):
        return self.boxes[(row["checked"], not row["required"])]

    def _rebuild_table(self):
        self._close_editor()
        for item in self.table.get_children():
            self.table.delete(item)
        self.row_by_item.clear()

        self.rows[:] = collect_rows()
        for row in self.rows:
            if "section" in row:
                self.table.insert(
                    "", "end", values=(row["section"], "", "", ""), tags=(SECTION_TAG,),
                )
                continue
            item = self.table.insert(
                "", "end", image=self._row_image(row), values=self._row_values(row),
            )
            self.row_by_item[item] = row

    def _refresh_row(self, item):
        row = self.row_by_item[item]
        self.table.item(item, image=self._row_image(row), values=self._row_values(row))

    def _set_choice(self, item, index):
        row = self.row_by_item[item]
        row["choice"] = index
        if row["declared"] or row["options"][index][1] is not None:
            row["checked"] = True
        self._refresh_row(item)

    def _toggle_check(self, item):
        row = self.row_by_item[item]
        if row["required"]:
            return

        row["checked"] = not row["checked"]
        if not row["declared"]:
            row["choice"] = 1 if (row["checked"] and len(row["options"]) > 1) else 0
            if row["checked"] and len(row["options"]) < 2:
                row["checked"] = False
                messagebox.showwarning(
                    "Manage Kits",
                    f"Sedona home holds no manifest for '{row['kit']}', so there is no "
                    "build to add it at.",
                )
        self._refresh_row(item)

    def _edit_action(self, item):
        row = self.row_by_item[item]
        cell = self.table.bbox(item, "action")
        if not cell:
            return

        labels = [label for label, _ in row["options"]]
        current = self._action_text(row)
        variable = tk.StringVar(value=current if current in labels else labels[row["choice"]])
        combo = ttk.Combobox(self.table, textvariable=variable, values=labels, state="readonly")
        combo.place(x=cell[0], y=cell[1], width=cell[2], height=cell[3])
        self._editor_widget = combo

        def commit(_event=None):
            if variable.get() in labels:
                self._set_choice(item, labels.index(variable.get()))
            self._close_editor()

        combo.bind("<<ComboboxSelected>>", commit)
        combo.bind("<Escape>", lambda _e: self._close_editor())
        combo.focus_set()
        combo.after_idle(lambda: combo.event_generate("<Down>"))

    def _on_click(self, event):
        self._close_editor()
        if self.table.identify_region(event.x, event.y) not in ("tree", "cell"):
            return
        item = self.table.identify_row(event.y)
        if item not in self.row_by_item:
            return

        column = self.table.identify_column(event.x)
        if column == "#0":
            self._toggle_check(item)
        elif column == "#4":
            self._edit_action(item)

    def _apply_changes(self, selections, removals, label, nothing_message, note=""):
        if not selections and not removals:
            messagebox.showinfo("Manage Kits", nothing_message)
            return

        changes, error = sax_file.apply_kit_selections(selections, removals, label=label)
        if error:
            messagebox.showerror("Kits unchanged", error)
            self._rebuild_table()
            return

        if not changes:
            messagebox.showinfo("Manage Kits", "The schema already reads that way.")
            return

        self._rebuild_table()
        if self.on_applied is not None:
            self.on_applied()

        app_state.set_status(
            f"schema kits changed ({len(changes)}) — save the file to keep it.",
            warn=True,
        )
        messagebox.showinfo(
            "Kits updated",
            f"The schema block now reads:\n\n{describe_changes(changes)}\n\n"
            + (note + "\n\n" if note else "")
            + "Save the file to write this to disk. The device's scode must hold these "
            "builds or the application will not run.",
        )

    def _upgrade_all(self):
        selections = []
        for row in self.rows:
            if "section" in row or not row["declared"] or not row["latest"]:
                continue
            latest_checksum = row["latest"][1]
            if latest_checksum != row["checksum"]:
                selections.append((row["kit"], latest_checksum))

        if selections:
            preview = "\n".join(
                f"    • {kit}: {build_label(palette.version_for_checksum(kit, checksum), checksum)}"
                for kit, checksum in selections
            )
            proceed = messagebox.askokcancel(
                "Upgrade all kits",
                f"{len(selections)} kit{'' if len(selections) == 1 else 's'} in this app's "
                f"schema will move to their latest installed build:\n\n{preview}\n\nContinue?",
                icon=messagebox.WARNING,
            )
            if not proceed:
                return

        self._apply_changes(
            selections, [],
            "upgrade all kits",
            "Every kit in the schema is already at its latest installed build.",
        )

    def _update_marked(self):
        selections = []
        removals = []
        for row in self.row_by_item.values():
            if row["declared"] and not row["checked"]:
                removals.append(row["kit"])
                continue
            if not row["checked"]:
                continue
            checksum = row["options"][row["choice"]][1]
            if checksum:
                selections.append((row["kit"], checksum))

        note = ""
        if removals:
            note = (
                "Removed kits are gone from the schema only. Any build of them still "
                "installed in Sedona home can be added back here."
            )

        self._apply_changes(
            selections, removals,
            "update kits",
            "Nothing is marked for a change. Pick a build in a kit's Action column, tick "
            "a kit to add it, or untick one to remove it.",
        )


def build_kits_panel(parent, on_applied, on_close):
    """Factory matching the pattern of properties.build_properties_panel."""
    return KitsPanel(parent, on_applied=on_applied, on_close=on_close)