import {
	type Component,
	Container,
	Input,
	isArrowDown,
	isArrowUp,
	isBackspace,
	isCtrlC,
	isCtrlO,
	isEnter,
	isEscape,
	Spacer,
	Text,
	TruncatedText,
	truncateToWidth,
} from "@mariozechner/pi-tui";
import type { SessionTreeNode } from "../../../core/session-manager.js";
import { theme } from "../theme/theme.js";
import { DynamicBorder } from "./dynamic-border.js";

/** Flattened tree node for navigation */
interface FlatNode {
	node: SessionTreeNode;
	/** Indentation level (each level = 2 spaces) */
	indent: number;
	/** Whether to show connector (├─ or └─) - true if parent has multiple children */
	showConnector: boolean;
	/** If showConnector, true = last sibling (└─), false = not last (├─) */
	isLast: boolean;
	/** For each ancestor branch point, true = show │ (more siblings below), false = show space */
	gutters: boolean[];
	/** True if this node is a root under a virtual branching root (multiple roots) */
	isVirtualRootChild: boolean;
}

/** Filter mode for tree display */
type FilterMode = "default" | "user-only" | "labeled-only" | "all";

/**
 * Tree list component with selection and ASCII art visualization
 */
/** Tool call info for lookup */
interface ToolCallInfo {
	name: string;
	arguments: Record<string, unknown>;
}

class TreeList implements Component {
	private flatNodes: FlatNode[] = [];
	private filteredNodes: FlatNode[] = [];
	private selectedIndex = 0;
	private currentLeafId: string | null;
	private maxVisibleLines: number;
	private filterMode: FilterMode = "default";
	private searchQuery = "";
	private toolCallMap: Map<string, ToolCallInfo> = new Map();
	private multipleRoots = false;

	public onSelect?: (entryId: string) => void;
	public onCancel?: () => void;
	public onLabelEdit?: (entryId: string, currentLabel: string | undefined) => void;

	constructor(tree: SessionTreeNode[], currentLeafId: string | null, maxVisibleLines: number) {
		this.currentLeafId = currentLeafId;
		this.maxVisibleLines = maxVisibleLines;
		this.multipleRoots = tree.length > 1;
		this.flatNodes = this.flattenTree(tree);
		this.applyFilter();

		// Start with current leaf selected
		const leafIndex = this.filteredNodes.findIndex((n) => n.node.entry.id === currentLeafId);
		if (leafIndex !== -1) {
			this.selectedIndex = leafIndex;
		} else {
			this.selectedIndex = Math.max(0, this.filteredNodes.length - 1);
		}
	}

	private flattenTree(roots: SessionTreeNode[]): FlatNode[] {
		const result: FlatNode[] = [];
		this.toolCallMap.clear();

		// Indentation rules:
		// - At indent 0: stay at 0 unless parent has >1 children (then +1)
		// - At indent 1: children always go to indent 2 (visual grouping of subtree)
		// - At indent 2+: stay flat for single-child chains, +1 only if parent branches

		// Stack items: [node, indent, justBranched, showConnector, isLast, gutters]
		type StackItem = [SessionTreeNode, number, boolean, boolean, boolean, boolean[], boolean];
		const stack: StackItem[] = [];

		// Add roots in reverse order
		// If multiple roots, treat them as children of a virtual root that branches
		const multipleRoots = roots.length > 1;
		for (let i = roots.length - 1; i >= 0; i--) {
			const isLast = i === roots.length - 1;
			stack.push([roots[i], multipleRoots ? 1 : 0, multipleRoots, multipleRoots, isLast, [], multipleRoots]);
		}

		while (stack.length > 0) {
			const [node, indent, justBranched, showConnector, isLast, gutters, isVirtualRootChild] = stack.pop()!;

			// Extract tool calls from assistant messages for later lookup
			const entry = node.entry;
			if (entry.type === "message" && entry.message.role === "assistant") {
				const content = (entry.message as { content?: unknown }).content;
				if (Array.isArray(content)) {
					for (const block of content) {
						if (typeof block === "object" && block !== null && "type" in block && block.type === "toolCall") {
							const tc = block as { id: string; name: string; arguments: Record<string, unknown> };
							this.toolCallMap.set(tc.id, { name: tc.name, arguments: tc.arguments });
						}
					}
				}
			}

			result.push({ node, indent, showConnector, isLast, gutters, isVirtualRootChild });

			const children = node.children;
			const multipleChildren = children.length > 1;

			// Calculate child indent
			let childIndent: number;
			if (multipleChildren) {
				// Parent branches: children get +1
				childIndent = indent + 1;
			} else if (justBranched && indent > 0) {
				// First generation after a branch: +1 for visual grouping
				childIndent = indent + 1;
			} else {
				// Single-child chain: stay flat
				childIndent = indent;
			}

			// Build gutters for children
			// If this node showed a connector, add a gutter entry for descendants
			const childGutters = showConnector ? [...gutters, !isLast] : gutters;

			// Add children in reverse order
			for (let i = children.length - 1; i >= 0; i--) {
				const childIsLast = i === children.length - 1;
				stack.push([
					children[i],
					childIndent,
					multipleChildren,
					multipleChildren,
					childIsLast,
					childGutters,
					false,
				]);
			}
		}

		return result;
	}

	private applyFilter(): void {
		// Remember currently selected node to preserve cursor position
		const previouslySelectedId = this.filteredNodes[this.selectedIndex]?.node.entry.id;

		const searchTokens = this.searchQuery.toLowerCase().split(/\s+/).filter(Boolean);

		this.filteredNodes = this.flatNodes.filter((flatNode) => {
			const entry = flatNode.node.entry;
			const isCurrentLeaf = entry.id === this.currentLeafId;

			// Skip assistant messages with only tool calls (no text) unless error/aborted
			// Always show current leaf so active position is visible
			if (entry.type === "message" && entry.message.role === "assistant" && !isCurrentLeaf) {
				const msg = entry.message as { stopReason?: string; content?: unknown };
				const hasText = this.hasTextContent(msg.content);
				const isErrorOrAborted = msg.stopReason && msg.stopReason !== "stop" && msg.stopReason !== "toolUse";
				// Only hide if no text AND not an error/aborted message
				if (!hasText && !isErrorOrAborted) {
					return false;
				}
			}

			// Apply filter mode
			let passesFilter = true;
			if (this.filterMode === "user-only") {
				passesFilter =
					(entry.type === "message" && entry.message.role === "user") ||
					(entry.type === "custom_message" && entry.display);
			} else if (this.filterMode === "labeled-only") {
				passesFilter = flatNode.node.label !== undefined;
			} else if (this.filterMode !== "all") {
				// Default mode: hide label and custom entries
				passesFilter = entry.type !== "label" && entry.type !== "custom";
			}

			if (!passesFilter) return false;

			// Apply search filter
			if (searchTokens.length > 0) {
				const nodeText = this.getSearchableText(flatNode.node).toLowerCase();
				return searchTokens.every((token) => nodeText.includes(token));
			}

			return true;
		});

		// Try to preserve cursor on the same node after filtering
		if (previouslySelectedId) {
			const newIndex = this.filteredNodes.findIndex((n) => n.node.entry.id === previouslySelectedId);
			if (newIndex !== -1) {
				this.selectedIndex = newIndex;
				return;
			}
		}

		// Fall back: clamp index if out of bounds
		if (this.selectedIndex >= this.filteredNodes.length) {
			this.selectedIndex = Math.max(0, this.filteredNodes.length - 1);
		}
	}

	/** Get searchable text content from a node */
	private getSearchableText(node: SessionTreeNode): string {
		const entry = node.entry;
		const parts: string[] = [];

		if (node.label) {
			parts.push(node.label);
		}

		switch (entry.type) {
			case "message": {
				const msg = entry.message;
				parts.push(msg.role);
				if ("content" in msg && msg.content) {
					parts.push(this.extractContent(msg.content));
				}
				if (msg.role === "bashExecution") {
					const bashMsg = msg as { command?: string };
					if (bashMsg.command) parts.push(bashMsg.command);
				}
				break;
			}
			case "custom_message": {
				parts.push(entry.customType);
				if (typeof entry.content === "string") {
					parts.push(entry.content);
				} else {
					parts.push(this.extractContent(entry.content));
				}
				break;
			}
			case "compaction":
				parts.push("compaction");
				break;
			case "branch_summary":
				parts.push("branch summary", entry.summary);
				break;
			case "model_change":
				parts.push("model", entry.modelId);
				break;
			case "thinking_level_change":
				parts.push("thinking", entry.thinkingLevel);
				break;
			case "custom":
				parts.push("custom", entry.customType);
				break;
			case "label":
				parts.push("label", entry.label ?? "");
				break;
		}

		return parts.join(" ");
	}

	invalidate(): void {}

	getSearchQuery(): string {
		return this.searchQuery;
	}

	getSelectedNode(): SessionTreeNode | undefined {
		return this.filteredNodes[this.selectedIndex]?.node;
	}

	updateNodeLabel(entryId: string, label: string | undefined): void {
		for (const flatNode of this.flatNodes) {
			if (flatNode.node.entry.id === entryId) {
				flatNode.node.label = label;
				break;
			}
		}
	}

	private getFilterLabel(): string {
		switch (this.filterMode) {
			case "user-only":
				return " [user]";
			case "labeled-only":
				return " [labeled]";
			case "all":
				return " [all]";
			default:
				return "";
		}
	}

	render(width: number): string[] {
		const lines: string[] = [];

		if (this.filteredNodes.length === 0) {
			lines.push(truncateToWidth(theme.fg("muted", "  No entries found"), width));
			lines.push(truncateToWidth(theme.fg("muted", `  (0/0)${this.getFilterLabel()}`), width));
			return lines;
		}

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

		for (let i = startIndex; i < endIndex; i++) {
			const flatNode = this.filteredNodes[i];
			const entry = flatNode.node.entry;
			const isSelected = i === this.selectedIndex;
			const isCurrentLeaf = entry.id === this.currentLeafId;

			// Build line: cursor + gutters + connector + extra indent + label + content + suffix
			const cursor = isSelected ? theme.fg("accent", "› ") : "  ";

			// If multiple roots, shift display (roots at 0, not 1)
			const displayIndent = this.multipleRoots ? Math.max(0, flatNode.indent - 1) : flatNode.indent;
			// Also shift gutters for multiple roots (skip first gutter which is the virtual root level)
			const displayGutters = this.multipleRoots ? flatNode.gutters.slice(1) : flatNode.gutters;

			// Build prefix: gutters + connector + extra spaces
			const gutterStr = displayGutters.map((g) => (g ? "│ " : "  ")).join("");
			const connector =
				flatNode.showConnector && !flatNode.isVirtualRootChild ? (flatNode.isLast ? "└─" : "├─") : "";
			// Extra indent for visual grouping beyond gutters/connector
			const prefixLevels = displayGutters.length + (connector ? 1 : 0);
			const extraIndent = "  ".repeat(Math.max(0, displayIndent - prefixLevels));
			const prefix = gutterStr + connector + extraIndent;

			const label = flatNode.node.label ? theme.fg("warning", `[${flatNode.node.label}] `) : "";
			const content = this.getEntryDisplayText(flatNode.node, isSelected);
			const suffix = isCurrentLeaf ? theme.fg("accent", " *") : "";

			const line = cursor + theme.fg("dim", prefix) + label + content + suffix;
			lines.push(truncateToWidth(line, width));
		}

		lines.push(
			truncateToWidth(
				theme.fg("muted", `  (${this.selectedIndex + 1}/${this.filteredNodes.length})${this.getFilterLabel()}`),
				width,
			),
		);

		return lines;
	}

	private getEntryDisplayText(node: SessionTreeNode, isSelected: boolean): string {
		const entry = node.entry;
		let result: string;

		const normalize = (s: string) => s.replace(/[\n\t]/g, " ").trim();

		switch (entry.type) {
			case "message": {
				const msg = entry.message;
				const role = msg.role;
				if (role === "user") {
					const msgWithContent = msg as { content?: unknown };
					const content = normalize(this.extractContent(msgWithContent.content));
					result = theme.fg("accent", "user: ") + content;
				} else if (role === "assistant") {
					const msgWithContent = msg as { content?: unknown; stopReason?: string; errorMessage?: string };
					const textContent = normalize(this.extractContent(msgWithContent.content));
					if (textContent) {
						result = theme.fg("success", "assistant: ") + textContent;
					} else if (msgWithContent.stopReason === "aborted") {
						result = theme.fg("warning", "assistant: ") + theme.fg("muted", "(aborted)");
					} else if (msgWithContent.errorMessage) {
						const errMsg = normalize(msgWithContent.errorMessage).slice(0, 80);
						result = theme.fg("error", "assistant: ") + errMsg;
					} else {
						result = theme.fg("muted", "assistant: (no content)");
					}
				} else if (role === "toolResult") {
					const toolMsg = msg as { toolCallId?: string; toolName?: string };
					const toolCall = toolMsg.toolCallId ? this.toolCallMap.get(toolMsg.toolCallId) : undefined;
					if (toolCall) {
						result = theme.fg("muted", this.formatToolCall(toolCall.name, toolCall.arguments));
					} else {
						result = theme.fg("muted", `[${toolMsg.toolName ?? "tool"}]`);
					}
				} else if (role === "bashExecution") {
					const bashMsg = msg as { command?: string };
					result = theme.fg("dim", `[bash]: ${normalize(bashMsg.command ?? "")}`);
				} else {
					result = theme.fg("dim", `[${role}]`);
				}
				break;
			}
			case "custom_message": {
				const content =
					typeof entry.content === "string"
						? entry.content
						: entry.content
								.filter((c): c is { type: "text"; text: string } => c.type === "text")
								.map((c) => c.text)
								.join("");
				result = theme.fg("customMessageLabel", `[${entry.customType}]: `) + normalize(content);
				break;
			}
			case "compaction": {
				const tokens = Math.round(entry.tokensBefore / 1000);
				result = theme.fg("borderAccent", `[compaction: ${tokens}k tokens]`);
				break;
			}
			case "branch_summary":
				result = theme.fg("warning", `[branch summary]: `) + normalize(entry.summary);
				break;
			case "model_change":
				result = theme.fg("dim", `[model: ${entry.modelId}]`);
				break;
			case "thinking_level_change":
				result = theme.fg("dim", `[thinking: ${entry.thinkingLevel}]`);
				break;
			case "custom":
				result = theme.fg("dim", `[custom: ${entry.customType}]`);
				break;
			case "label":
				result = theme.fg("dim", `[label: ${entry.label ?? "(cleared)"}]`);
				break;
			default:
				result = "";
		}

		return isSelected ? theme.bold(result) : result;
	}

	private extractContent(content: unknown): string {
		const maxLen = 200;
		if (typeof content === "string") return content.slice(0, maxLen);
		if (Array.isArray(content)) {
			let result = "";
			for (const c of content) {
				if (typeof c === "object" && c !== null && "type" in c && c.type === "text") {
					result += (c as { text: string }).text;
					if (result.length >= maxLen) return result.slice(0, maxLen);
				}
			}
			return result;
		}
		return "";
	}

	private hasTextContent(content: unknown): boolean {
		if (typeof content === "string") return content.trim().length > 0;
		if (Array.isArray(content)) {
			for (const c of content) {
				if (typeof c === "object" && c !== null && "type" in c && c.type === "text") {
					const text = (c as { text?: string }).text;
					if (text && text.trim().length > 0) return true;
				}
			}
		}
		return false;
	}

	private formatToolCall(name: string, args: Record<string, unknown>): string {
		const shortenPath = (p: string): string => {
			const home = process.env.HOME || process.env.USERPROFILE || "";
			if (home && p.startsWith(home)) return `~${p.slice(home.length)}`;
			return p;
		};

		switch (name) {
			case "read": {
				const path = shortenPath(String(args.path || args.file_path || ""));
				const offset = args.offset as number | undefined;
				const limit = args.limit as number | undefined;
				let display = path;
				if (offset !== undefined || limit !== undefined) {
					const start = offset ?? 1;
					const end = limit !== undefined ? start + limit - 1 : "";
					display += `:${start}${end ? `-${end}` : ""}`;
				}
				return `[read: ${display}]`;
			}
			case "write": {
				const path = shortenPath(String(args.path || args.file_path || ""));
				return `[write: ${path}]`;
			}
			case "edit": {
				const path = shortenPath(String(args.path || args.file_path || ""));
				return `[edit: ${path}]`;
			}
			case "bash": {
				const cmd = String(args.command || "").slice(0, 50);
				return `[bash: ${cmd}${(args.command as string)?.length > 50 ? "..." : ""}]`;
			}
			case "grep": {
				const pattern = String(args.pattern || "");
				const path = shortenPath(String(args.path || "."));
				return `[grep: /${pattern}/ in ${path}]`;
			}
			case "find": {
				const pattern = String(args.pattern || "");
				const path = shortenPath(String(args.path || "."));
				return `[find: ${pattern} in ${path}]`;
			}
			case "ls": {
				const path = shortenPath(String(args.path || "."));
				return `[ls: ${path}]`;
			}
			default: {
				// Custom tool - show name and truncated JSON args
				const argsStr = JSON.stringify(args).slice(0, 40);
				return `[${name}: ${argsStr}${JSON.stringify(args).length > 40 ? "..." : ""}]`;
			}
		}
	}

	handleInput(keyData: string): void {
		if (isArrowUp(keyData)) {
			this.selectedIndex = this.selectedIndex === 0 ? this.filteredNodes.length - 1 : this.selectedIndex - 1;
		} else if (isArrowDown(keyData)) {
			this.selectedIndex = this.selectedIndex === this.filteredNodes.length - 1 ? 0 : this.selectedIndex + 1;
		} else if (isEnter(keyData)) {
			const selected = this.filteredNodes[this.selectedIndex];
			if (selected && this.onSelect) {
				this.onSelect(selected.node.entry.id);
			}
		} else if (isEscape(keyData)) {
			if (this.searchQuery) {
				this.searchQuery = "";
				this.applyFilter();
			} else {
				this.onCancel?.();
			}
		} else if (isCtrlC(keyData)) {
			this.onCancel?.();
		} else if (isCtrlO(keyData)) {
			// Cycle filter: default → user-only → labeled-only → all → default
			const modes: FilterMode[] = ["default", "user-only", "labeled-only", "all"];
			const currentIndex = modes.indexOf(this.filterMode);
			this.filterMode = modes[(currentIndex + 1) % modes.length];
			this.applyFilter();
		} else if (isBackspace(keyData)) {
			if (this.searchQuery.length > 0) {
				this.searchQuery = this.searchQuery.slice(0, -1);
				this.applyFilter();
			}
		} else if (keyData === "l" && !this.searchQuery) {
			const selected = this.filteredNodes[this.selectedIndex];
			if (selected && this.onLabelEdit) {
				this.onLabelEdit(selected.node.entry.id, selected.node.label);
			}
		} else {
			const hasControlChars = [...keyData].some((ch) => {
				const code = ch.charCodeAt(0);
				return code < 32 || code === 0x7f || (code >= 0x80 && code <= 0x9f);
			});
			if (!hasControlChars && keyData.length > 0) {
				this.searchQuery += keyData;
				this.applyFilter();
			}
		}
	}
}

/** Component that displays the current search query */
class SearchLine implements Component {
	constructor(private treeList: TreeList) {}

	invalidate(): void {}

	render(width: number): string[] {
		const query = this.treeList.getSearchQuery();
		if (query) {
			return [truncateToWidth(`  ${theme.fg("muted", "Search:")} ${theme.fg("accent", query)}`, width)];
		}
		return [truncateToWidth(`  ${theme.fg("muted", "Search:")}`, width)];
	}

	handleInput(_keyData: string): void {}
}

/** Label input component shown when editing a label */
class LabelInput implements Component {
	private input: Input;
	private entryId: string;
	public onSubmit?: (entryId: string, label: string | undefined) => void;
	public onCancel?: () => void;

	constructor(entryId: string, currentLabel: string | undefined) {
		this.entryId = entryId;
		this.input = new Input();
		if (currentLabel) {
			this.input.setValue(currentLabel);
		}
	}

	invalidate(): void {}

	render(width: number): string[] {
		const lines: string[] = [];
		const indent = "  ";
		const availableWidth = width - indent.length;
		lines.push(truncateToWidth(`${indent}${theme.fg("muted", "Label (empty to remove):")}`, width));
		lines.push(...this.input.render(availableWidth).map((line) => truncateToWidth(`${indent}${line}`, width)));
		lines.push(truncateToWidth(`${indent}${theme.fg("dim", "enter: save  esc: cancel")}`, width));
		return lines;
	}

	handleInput(keyData: string): void {
		if (isEnter(keyData)) {
			const value = this.input.getValue().trim();
			this.onSubmit?.(this.entryId, value || undefined);
		} else if (isEscape(keyData)) {
			this.onCancel?.();
		} else {
			this.input.handleInput(keyData);
		}
	}
}

/**
 * Component that renders a session tree selector for navigation
 */
export class TreeSelectorComponent extends Container {
	private treeList: TreeList;
	private labelInput: LabelInput | null = null;
	private labelInputContainer: Container;
	private treeContainer: Container;
	private onLabelChangeCallback?: (entryId: string, label: string | undefined) => void;

	constructor(
		tree: SessionTreeNode[],
		currentLeafId: string | null,
		terminalHeight: number,
		onSelect: (entryId: string) => void,
		onCancel: () => void,
		onLabelChange?: (entryId: string, label: string | undefined) => void,
	) {
		super();

		this.onLabelChangeCallback = onLabelChange;
		const maxVisibleLines = Math.max(5, Math.floor(terminalHeight / 2));

		this.treeList = new TreeList(tree, currentLeafId, maxVisibleLines);
		this.treeList.onSelect = onSelect;
		this.treeList.onCancel = onCancel;
		this.treeList.onLabelEdit = (entryId, currentLabel) => this.showLabelInput(entryId, currentLabel);

		this.treeContainer = new Container();
		this.treeContainer.addChild(this.treeList);

		this.labelInputContainer = new Container();

		this.addChild(new Spacer(1));
		this.addChild(new Text(theme.bold("Session Tree"), 1, 0));
		this.addChild(new DynamicBorder());
		this.addChild(new TruncatedText(theme.fg("muted", "  Type to search. l: label. ^O: cycle filter"), 0, 0));
		this.addChild(new SearchLine(this.treeList));
		this.addChild(new DynamicBorder());
		this.addChild(new Spacer(1));
		this.addChild(this.treeContainer);
		this.addChild(this.labelInputContainer);
		this.addChild(new Spacer(1));
		this.addChild(new DynamicBorder());

		if (tree.length === 0) {
			setTimeout(() => onCancel(), 100);
		}
	}

	private showLabelInput(entryId: string, currentLabel: string | undefined): void {
		this.labelInput = new LabelInput(entryId, currentLabel);
		this.labelInput.onSubmit = (id, label) => {
			this.treeList.updateNodeLabel(id, label);
			this.onLabelChangeCallback?.(id, label);
			this.hideLabelInput();
		};
		this.labelInput.onCancel = () => this.hideLabelInput();

		this.treeContainer.clear();
		this.labelInputContainer.clear();
		this.labelInputContainer.addChild(this.labelInput);
	}

	private hideLabelInput(): void {
		this.labelInput = null;
		this.labelInputContainer.clear();
		this.treeContainer.clear();
		this.treeContainer.addChild(this.treeList);
	}

	handleInput(keyData: string): void {
		if (this.labelInput) {
			this.labelInput.handleInput(keyData);
		} else {
			this.treeList.handleInput(keyData);
		}
	}

	getTreeList(): TreeList {
		return this.treeList;
	}
}