import { type Model, modelsAreEqual } from "@mariozechner/companion-ai";
import {
  Container,
  type Focusable,
  fuzzyFilter,
  getEditorKeybindings,
  Input,
  Spacer,
  Text,
  type TUI,
} from "@mariozechner/companion-tui";
import type { ModelRegistry } from "../../../core/model-registry.js";
import type { SettingsManager } from "../../../core/settings-manager.js";
import { theme } from "../theme/theme.js";
import { DynamicBorder } from "./dynamic-border.js";
import { keyHint } from "./keybinding-hints.js";

interface ModelItem {
  provider: string;
  id: string;
  model: Model<any>;
}

interface ScopedModelItem {
  model: Model<any>;
  thinkingLevel?: string;
}

type ModelScope = "all" | "scoped";

/**
 * Component that renders a model selector with search
 */
export class ModelSelectorComponent extends Container implements Focusable {
  private searchInput: Input;

  // Focusable implementation - propagate to searchInput for IME cursor positioning
  private _focused = false;
  get focused(): boolean {
    return this._focused;
  }
  set focused(value: boolean) {
    this._focused = value;
    this.searchInput.focused = value;
  }
  private listContainer: Container;
  private allModels: ModelItem[] = [];
  private scopedModelItems: ModelItem[] = [];
  private activeModels: ModelItem[] = [];
  private filteredModels: ModelItem[] = [];
  private selectedIndex: number = 0;
  private currentModel?: Model<any>;
  private settingsManager: SettingsManager;
  private modelRegistry: ModelRegistry;
  private onSelectCallback: (model: Model<any>) => void;
  private onCancelCallback: () => void;
  private errorMessage?: string;
  private tui: TUI;
  private scopedModels: ReadonlyArray<ScopedModelItem>;
  private scope: ModelScope = "all";
  private scopeText?: Text;
  private scopeHintText?: Text;

  constructor(
    tui: TUI,
    currentModel: Model<any> | undefined,
    settingsManager: SettingsManager,
    modelRegistry: ModelRegistry,
    scopedModels: ReadonlyArray<ScopedModelItem>,
    onSelect: (model: Model<any>) => void,
    onCancel: () => void,
    initialSearchInput?: string,
  ) {
    super();

    this.tui = tui;
    this.currentModel = currentModel;
    this.settingsManager = settingsManager;
    this.modelRegistry = modelRegistry;
    this.scopedModels = scopedModels;
    this.scope = scopedModels.length > 0 ? "scoped" : "all";
    this.onSelectCallback = onSelect;
    this.onCancelCallback = onCancel;

    // Add top border
    this.addChild(new DynamicBorder());
    this.addChild(new Spacer(1));

    // Add hint about model filtering
    if (scopedModels.length > 0) {
      this.scopeText = new Text(this.getScopeText(), 0, 0);
      this.addChild(this.scopeText);
      this.scopeHintText = new Text(this.getScopeHintText(), 0, 0);
      this.addChild(this.scopeHintText);
    } else {
      const hintText =
        "Only showing models with configured API keys (see README for details)";
      this.addChild(new Text(theme.fg("warning", hintText), 0, 0));
    }
    this.addChild(new Spacer(1));

    // Create search input
    this.searchInput = new Input();
    if (initialSearchInput) {
      this.searchInput.setValue(initialSearchInput);
    }
    this.searchInput.onSubmit = () => {
      // Enter on search input selects the first filtered item
      if (this.filteredModels[this.selectedIndex]) {
        this.handleSelect(this.filteredModels[this.selectedIndex].model);
      }
    };
    this.addChild(this.searchInput);

    this.addChild(new Spacer(1));

    // Create list container
    this.listContainer = new Container();
    this.addChild(this.listContainer);

    this.addChild(new Spacer(1));

    // Add bottom border
    this.addChild(new DynamicBorder());

    // Load models and do initial render
    this.loadModels().then(() => {
      if (initialSearchInput) {
        this.filterModels(initialSearchInput);
      } else {
        this.updateList();
      }
      // Request re-render after models are loaded
      this.tui.requestRender();
    });
  }

  private async loadModels(): Promise<void> {
    let models: ModelItem[];

    // Refresh to pick up any changes to models.json
    this.modelRegistry.refresh();

    // Check for models.json errors
    const loadError = this.modelRegistry.getError();
    if (loadError) {
      this.errorMessage = loadError;
    }

    // Load available models (built-in models still work even if models.json failed)
    try {
      const availableModels = await this.modelRegistry.getAvailable();
      models = availableModels.map((model: Model<any>) => ({
        provider: model.provider,
        id: model.id,
        model,
      }));
    } catch (error) {
      this.allModels = [];
      this.scopedModelItems = [];
      this.activeModels = [];
      this.filteredModels = [];
      this.errorMessage =
        error instanceof Error ? error.message : String(error);
      return;
    }

    this.allModels = this.sortModels(models);
    this.scopedModelItems = this.sortModels(
      this.scopedModels.map((scoped) => ({
        provider: scoped.model.provider,
        id: scoped.model.id,
        model: scoped.model,
      })),
    );
    this.activeModels =
      this.scope === "scoped" ? this.scopedModelItems : this.allModels;
    this.filteredModels = this.activeModels;
    this.selectedIndex = Math.min(
      this.selectedIndex,
      Math.max(0, this.filteredModels.length - 1),
    );
  }

  private sortModels(models: ModelItem[]): ModelItem[] {
    const sorted = [...models];
    // Sort: current model first, then by provider
    sorted.sort((a, b) => {
      const aIsCurrent = modelsAreEqual(this.currentModel, a.model);
      const bIsCurrent = modelsAreEqual(this.currentModel, b.model);
      if (aIsCurrent && !bIsCurrent) return -1;
      if (!aIsCurrent && bIsCurrent) return 1;
      return a.provider.localeCompare(b.provider);
    });
    return sorted;
  }

  private getScopeText(): string {
    const allText =
      this.scope === "all"
        ? theme.fg("accent", "all")
        : theme.fg("muted", "all");
    const scopedText =
      this.scope === "scoped"
        ? theme.fg("accent", "scoped")
        : theme.fg("muted", "scoped");
    return `${theme.fg("muted", "Scope: ")}${allText}${theme.fg("muted", " | ")}${scopedText}`;
  }

  private getScopeHintText(): string {
    return keyHint("tab", "scope") + theme.fg("muted", " (all/scoped)");
  }

  private setScope(scope: ModelScope): void {
    if (this.scope === scope) return;
    this.scope = scope;
    this.activeModels =
      this.scope === "scoped" ? this.scopedModelItems : this.allModels;
    this.selectedIndex = 0;
    this.filterModels(this.searchInput.getValue());
    if (this.scopeText) {
      this.scopeText.setText(this.getScopeText());
    }
  }

  private filterModels(query: string): void {
    this.filteredModels = query
      ? fuzzyFilter(
          this.activeModels,
          query,
          ({ id, provider }) => `${id} ${provider}`,
        )
      : this.activeModels;
    this.selectedIndex = Math.min(
      this.selectedIndex,
      Math.max(0, this.filteredModels.length - 1),
    );
    this.updateList();
  }

  private updateList(): void {
    this.listContainer.clear();

    const maxVisible = 10;
    const startIndex = Math.max(
      0,
      Math.min(
        this.selectedIndex - Math.floor(maxVisible / 2),
        this.filteredModels.length - maxVisible,
      ),
    );
    const endIndex = Math.min(
      startIndex + maxVisible,
      this.filteredModels.length,
    );

    // Show visible slice of filtered models
    for (let i = startIndex; i < endIndex; i++) {
      const item = this.filteredModels[i];
      if (!item) continue;

      const isSelected = i === this.selectedIndex;
      const isCurrent = modelsAreEqual(this.currentModel, item.model);

      let line = "";
      if (isSelected) {
        const prefix = theme.fg("accent", "→ ");
        const modelText = `${item.id}`;
        const providerBadge = theme.fg("muted", `[${item.provider}]`);
        const checkmark = isCurrent ? theme.fg("success", " ✓") : "";
        line = `${prefix + theme.fg("accent", modelText)} ${providerBadge}${checkmark}`;
      } else {
        const modelText = `  ${item.id}`;
        const providerBadge = theme.fg("muted", `[${item.provider}]`);
        const checkmark = isCurrent ? theme.fg("success", " ✓") : "";
        line = `${modelText} ${providerBadge}${checkmark}`;
      }

      this.listContainer.addChild(new Text(line, 0, 0));
    }

    // Add scroll indicator if needed
    if (startIndex > 0 || endIndex < this.filteredModels.length) {
      const scrollInfo = theme.fg(
        "muted",
        `  (${this.selectedIndex + 1}/${this.filteredModels.length})`,
      );
      this.listContainer.addChild(new Text(scrollInfo, 0, 0));
    }

    // Show error message or "no results" if empty
    if (this.errorMessage) {
      // Show error in red
      const errorLines = this.errorMessage.split("\n");
      for (const line of errorLines) {
        this.listContainer.addChild(new Text(theme.fg("error", line), 0, 0));
      }
    } else if (this.filteredModels.length === 0) {
      this.listContainer.addChild(
        new Text(theme.fg("muted", "  No matching models"), 0, 0),
      );
    } else {
      const selected = this.filteredModels[this.selectedIndex];
      this.listContainer.addChild(new Spacer(1));
      this.listContainer.addChild(
        new Text(
          theme.fg("muted", `  Model Name: ${selected.model.name}`),
          0,
          0,
        ),
      );
    }
  }

  handleInput(keyData: string): void {
    const kb = getEditorKeybindings();
    if (kb.matches(keyData, "tab")) {
      if (this.scopedModelItems.length > 0) {
        const nextScope: ModelScope = this.scope === "all" ? "scoped" : "all";
        this.setScope(nextScope);
        if (this.scopeHintText) {
          this.scopeHintText.setText(this.getScopeHintText());
        }
      }
      return;
    }
    // Up arrow - wrap to bottom when at top
    if (kb.matches(keyData, "selectUp")) {
      if (this.filteredModels.length === 0) return;
      this.selectedIndex =
        this.selectedIndex === 0
          ? this.filteredModels.length - 1
          : this.selectedIndex - 1;
      this.updateList();
    }
    // Down arrow - wrap to top when at bottom
    else if (kb.matches(keyData, "selectDown")) {
      if (this.filteredModels.length === 0) return;
      this.selectedIndex =
        this.selectedIndex === this.filteredModels.length - 1
          ? 0
          : this.selectedIndex + 1;
      this.updateList();
    }
    // Enter
    else if (kb.matches(keyData, "selectConfirm")) {
      const selectedModel = this.filteredModels[this.selectedIndex];
      if (selectedModel) {
        this.handleSelect(selectedModel.model);
      }
    }
    // Escape or Ctrl+C
    else if (kb.matches(keyData, "selectCancel")) {
      this.onCancelCallback();
    }
    // Pass everything else to search input
    else {
      this.searchInput.handleInput(keyData);
      this.filterModels(this.searchInput.getValue());
    }
  }

  private handleSelect(model: Model<any>): void {
    // Save as new default
    this.settingsManager.setDefaultModelAndProvider(model.provider, model.id);
    this.onSelectCallback(model);
  }

  getSearchInput(): Input {
    return this.searchInput;
  }
}