import { AgenticSectionType, MessageRole } from '$lib/enums';
import type { ApiChatCompletionToolCall } from '$lib/types/api';
import type { DatabaseMessage } from '$lib/types/database';
import { deriveAgenticSections, hasAgenticContent } from '$lib/utils/agentic';
import { describe, expect, it } from 'vitest';

function makeAssistant(overrides: Partial<DatabaseMessage> = {}): DatabaseMessage {
	return {
		children: [],
		content: overrides.content ?? '',
		convId: 'conv-1',
		id: overrides.id ?? 'ast-1',
		parent: null,
		role: MessageRole.ASSISTANT,
		timestamp: Date.now(),
		type: 'text',
		...overrides
	} as DatabaseMessage;
}

function makeToolMsg(overrides: Partial<DatabaseMessage> = {}): DatabaseMessage {
	return {
		children: [],
		content: overrides.content ?? 'tool result',
		convId: 'conv-1',
		id: overrides.id ?? 'tool-1',
		parent: null,
		role: MessageRole.TOOL,
		timestamp: Date.now(),
		toolCallId: overrides.toolCallId ?? 'call_1',
		type: 'text',
		...overrides
	} as DatabaseMessage;
}

describe('deriveAgenticSections', () => {
	it('returns empty array for assistant with no content', () => {
		const msg = makeAssistant({ content: '' });
		const sections = deriveAgenticSections(msg);

		expect(sections).toEqual([]);
	});

	it('returns text section for simple assistant message', () => {
		const msg = makeAssistant({ content: 'Hello world' });
		const sections = deriveAgenticSections(msg);

		expect(sections).toHaveLength(1);
		expect(sections[0].type).toBe(AgenticSectionType.TEXT);
		expect(sections[0].content).toBe('Hello world');
	});

	it('returns reasoning + text for message with reasoning', () => {
		const msg = makeAssistant({
			content: 'Answer is 4.',
			reasoningContent: 'Let me think...'
		});
		const sections = deriveAgenticSections(msg);

		expect(sections).toHaveLength(2);
		expect(sections[0].type).toBe(AgenticSectionType.REASONING);
		expect(sections[0].content).toBe('Let me think...');
		expect(sections[1].type).toBe(AgenticSectionType.TEXT);
	});

	it('single turn: assistant with tool calls and results', () => {
		const msg = makeAssistant({
			content: 'Let me check.',
			toolCalls: JSON.stringify([
				{
					function: { arguments: '{"q":"test"}', name: 'search' },
					id: 'call_1',
					type: 'function'
				}
			])
		});
		const toolResult = makeToolMsg({
			content: 'Found 3 results',
			toolCallId: 'call_1'
		});
		const sections = deriveAgenticSections(msg, [toolResult]);

		expect(sections).toHaveLength(2);
		expect(sections[0].type).toBe(AgenticSectionType.TEXT);
		expect(sections[1].type).toBe(AgenticSectionType.TOOL_CALL);
		expect(sections[1].toolName).toBe('search');
		expect(sections[1].toolResult).toBe('Found 3 results');
	});

	it('single turn: pending tool call without result', () => {
		const msg = makeAssistant({
			toolCalls: JSON.stringify([
				{ function: { arguments: '{}', name: 'bash' }, id: 'call_1', type: 'function' }
			])
		});
		const sections = deriveAgenticSections(msg, [], [], true);

		expect(sections).toHaveLength(1);
		expect(sections[0].type).toBe(AgenticSectionType.TOOL_CALL_PENDING);
		expect(sections[0].toolName).toBe('bash');
	});

	it('chat-streaming write_file surfaces as TOOL_CALL_PENDING with partial toolArgs (not TOOL_CALL_STREAMING)', () => {
		// Regression: while the LLM is emitting a write_file tool call's
		// args, `chat.svelte.ts` JSON-encodes the partial tool-call array on
		// every chunk, so `parseToolCalls` succeeds and the section is
		// classified TOOL_CALL_PENDING - not TOOL_CALL_STREAMING (which is
		// only produced from the `streamingToolCalls` parameter, never set
		// by current UI callers). Streaming-only UI like auto-scroll in the
		// code block must still trigger, driven by `isStreaming && (isPending
		// || isStreamingCall)`, not `isStreamingCall` alone.
		const partialArgs = '{"path":"/Users/fifa2026.html","content":"<!DOCTYPE h';
		const msg = makeAssistant({
			toolCalls: JSON.stringify([
				{ function: { arguments: partialArgs, name: 'write_file' }, id: 'call_1', type: 'function' }
			])
		});
		const sections = deriveAgenticSections(msg, [], [], true);

		expect(sections).toHaveLength(1);
		expect(sections[0].type).toBe(AgenticSectionType.TOOL_CALL_PENDING);
		expect(sections[0].type).not.toBe(AgenticSectionType.TOOL_CALL_STREAMING);
		expect(sections[0].toolName).toBe('write_file');
		expect(sections[0].toolArgs).toBe(partialArgs);
	});

	it('multi-turn: two assistant turns grouped as one session', () => {
		const assistant1 = makeAssistant({
			content: 'Turn 1 text',
			id: 'ast-1',
			toolCalls: JSON.stringify([
				{
					function: { arguments: '{"q":"foo"}', name: 'search' },
					id: 'call_1',
					type: 'function'
				}
			])
		});
		const tool1 = makeToolMsg({ content: 'result 1', id: 'tool-1', toolCallId: 'call_1' });
		const assistant2 = makeAssistant({
			content: 'Final answer based on results.',
			id: 'ast-2'
		});
		// toolMessages contains both tool result and continuation assistant
		const sections = deriveAgenticSections(assistant1, [tool1, assistant2]);

		expect(sections).toHaveLength(3);
		// Turn 1
		expect(sections[0].type).toBe(AgenticSectionType.TEXT);
		expect(sections[0].content).toBe('Turn 1 text');
		expect(sections[1].type).toBe(AgenticSectionType.TOOL_CALL);
		expect(sections[1].toolName).toBe('search');
		expect(sections[1].toolResult).toBe('result 1');
		// Turn 2 (final)
		expect(sections[2].type).toBe(AgenticSectionType.TEXT);
		expect(sections[2].content).toBe('Final answer based on results.');
	});

	it('multi-turn: three turns with tool calls', () => {
		const assistant1 = makeAssistant({
			content: '',
			id: 'ast-1',
			toolCalls: JSON.stringify([
				{
					function: { arguments: '{}', name: 'list_files' },
					id: 'call_1',
					type: 'function'
				}
			])
		});
		const tool1 = makeToolMsg({ content: 'file1 file2', id: 'tool-1', toolCallId: 'call_1' });
		const assistant2 = makeAssistant({
			content: 'Reading file1...',
			id: 'ast-2',
			toolCalls: JSON.stringify([
				{
					function: { arguments: '{"path":"file1"}', name: 'read_file' },
					id: 'call_2',
					type: 'function'
				}
			])
		});
		const tool2 = makeToolMsg({
			content: 'contents of file1',
			id: 'tool-2',
			toolCallId: 'call_2'
		});
		const assistant3 = makeAssistant({
			content: 'Here is the analysis.',
			id: 'ast-3',
			reasoningContent: 'The file contains...'
		});
		const sections = deriveAgenticSections(assistant1, [tool1, assistant2, tool2, assistant3]);

		// Turn 1: tool_call (no text since content is empty)
		// Turn 2: text + tool_call
		// Turn 3: reasoning + text
		expect(sections).toHaveLength(5);
		expect(sections[0].type).toBe(AgenticSectionType.TOOL_CALL);
		expect(sections[0].toolName).toBe('list_files');
		expect(sections[1].type).toBe(AgenticSectionType.TEXT);
		expect(sections[1].content).toBe('Reading file1...');
		expect(sections[2].type).toBe(AgenticSectionType.TOOL_CALL);
		expect(sections[2].toolName).toBe('read_file');
		expect(sections[3].type).toBe(AgenticSectionType.REASONING);
		expect(sections[4].type).toBe(AgenticSectionType.TEXT);
		expect(sections[4].content).toBe('Here is the analysis.');
	});

	it('returns REASONING_PENDING when streaming with only reasoning content', () => {
		const msg = makeAssistant({
			reasoningContent: 'Let me think about this...'
		});
		const sections = deriveAgenticSections(msg, [], [], true);

		expect(sections).toHaveLength(1);
		expect(sections[0].type).toBe(AgenticSectionType.REASONING_PENDING);
		expect(sections[0].content).toBe('Let me think about this...');
	});

	it('returns REASONING (not pending) when streaming but text content has appeared', () => {
		const msg = makeAssistant({
			content: 'The answer is',
			reasoningContent: 'Let me think...'
		});
		const sections = deriveAgenticSections(msg, [], [], true);

		expect(sections).toHaveLength(2);
		expect(sections[0].type).toBe(AgenticSectionType.REASONING);
		expect(sections[1].type).toBe(AgenticSectionType.TEXT);
	});

	it('returns REASONING (not pending) when not streaming', () => {
		const msg = makeAssistant({
			reasoningContent: 'Let me think...'
		});
		const sections = deriveAgenticSections(msg, [], [], false);

		expect(sections).toHaveLength(1);
		expect(sections[0].type).toBe(AgenticSectionType.REASONING);
	});

	it('multi-turn: streaming tool calls on last turn', () => {
		const assistant1 = makeAssistant({
			toolCalls: JSON.stringify([
				{ function: { arguments: '{}', name: 'search' }, id: 'call_1', type: 'function' }
			])
		});
		const tool1 = makeToolMsg({ content: 'result', toolCallId: 'call_1' });
		const assistant2 = makeAssistant({ content: '', id: 'ast-2' });
		const streamingToolCalls: ApiChatCompletionToolCall[] = [
			{ function: { arguments: '{"pa', name: 'write_file' }, id: 'call_2', type: 'function' }
		];
		const sections = deriveAgenticSections(assistant1, [tool1, assistant2], streamingToolCalls);

		// Turn 1: tool_call
		// Turn 2 (streaming): streaming tool call
		expect(sections.some((s) => s.type === AgenticSectionType.TOOL_CALL)).toBe(true);
		expect(sections.some((s) => s.type === AgenticSectionType.TOOL_CALL_STREAMING)).toBe(true);
	});
});

describe('hasAgenticContent', () => {
	it('returns false for plain assistant', () => {
		const msg = makeAssistant({ content: 'Just text' });

		expect(hasAgenticContent(msg)).toBe(false);
	});

	it('returns true when message has toolCalls', () => {
		const msg = makeAssistant({
			toolCalls: JSON.stringify([
				{ function: { arguments: '{}', name: 'test' }, id: 'call_1', type: 'function' }
			])
		});

		expect(hasAgenticContent(msg)).toBe(true);
	});

	it('returns true when toolMessages are provided', () => {
		const msg = makeAssistant();
		const tool = makeToolMsg();

		expect(hasAgenticContent(msg, [tool])).toBe(true);
	});

	it('returns false for empty toolCalls JSON', () => {
		const msg = makeAssistant({ toolCalls: '[]' });

		expect(hasAgenticContent(msg)).toBe(false);
	});
});

// The turn-section cache: completed turns are immutable, so repeated
// derivations return the same section objects - which is what keeps tool
// block props stable while another turn streams. Every field the cache
// compares must invalidate it; a miss here renders stale content.

describe('completed turn section reuse', () => {
	const toolCallsJson = JSON.stringify([
		{ function: { arguments: '{"path":"/a"}', name: 'test' }, id: 'call_1', type: 'function' }
	]);

	function makeSession() {
		return {
			anchor: makeAssistant({
				content: 'answer',
				reasoningContent: 'thinking',
				toolCalls: toolCallsJson
			}),
			tools: [makeToolMsg({ content: 'tool result', extra: [{ type: 'file' } as never] })]
		};
	}

	it('returns the same section objects for unchanged inputs', () => {
		const { anchor, tools } = makeSession();
		const first = deriveAgenticSections(anchor, tools, [], false);
		const second = deriveAgenticSections(anchor, tools, [], false);

		expect(second[0]).toBe(first[0]);
		expect(second[1]).toBe(first[1]);
	});

	it('recomputes when the assistant content changes', () => {
		const { anchor, tools } = makeSession();
		const first = deriveAgenticSections(anchor, tools, [], false);

		anchor.content = 'edited';
		const second = deriveAgenticSections(anchor, tools, [], false);

		expect(second).not.toBe(first);
		expect(second.some((s) => s.type === AgenticSectionType.TEXT && s.content === 'edited')).toBe(
			true
		);
	});

	it('recomputes when reasoning content changes', () => {
		const { anchor, tools } = makeSession();
		const first = deriveAgenticSections(anchor, tools, [], false);

		anchor.reasoningContent = 'new thinking';
		const second = deriveAgenticSections(anchor, tools, [], false);

		expect(second).not.toBe(first);
	});

	it('recomputes when toolCalls change', () => {
		const { anchor, tools } = makeSession();
		const first = deriveAgenticSections(anchor, tools, [], false);

		anchor.toolCalls = '[]';
		const second = deriveAgenticSections(anchor, tools, [], false);

		expect(second).not.toBe(first);
	});

	it('recomputes when a tool result or its extras change', () => {
		const { anchor, tools } = makeSession();
		const first = deriveAgenticSections(anchor, tools, [], false);

		tools[0].content = 'new tool result';
		expect(deriveAgenticSections(anchor, tools, [], false)).not.toBe(first);

		const firstAfterContent = deriveAgenticSections(anchor, tools, [], false);

		tools[0].extra = [{ type: 'image' } as never];
		expect(deriveAgenticSections(anchor, tools, [], false)).not.toBe(firstAfterContent);
	});

	it('never reuses the streaming turn', () => {
		const { anchor, tools } = makeSession();
		const first = deriveAgenticSections(anchor, tools, [], true);
		const second = deriveAgenticSections(anchor, tools, [], true);

		expect(second).not.toBe(first);
	});

	it('keeps completed turns stable while the last turn streams', () => {
		const anchor = makeAssistant({
			content: 'turn one',
			id: 'ast-1',
			toolCalls: JSON.stringify([
				{ function: { arguments: '{}', name: 'test' }, id: 'call_1', type: 'function' }
			])
		});
		const continuation = makeAssistant({ content: 'turn two', id: 'ast-2' });
		const tools = [
			makeToolMsg({ content: 'r1', id: 'tool-1', toolCallId: 'call_1' }),
			continuation,
			makeToolMsg({ content: 'r2', id: 'tool-2', toolCallId: 'call_2' })
		];
		const first = deriveAgenticSections(anchor, tools, [], true);
		const second = deriveAgenticSections(anchor, tools, [], true);

		// turn one is complete: identical section objects across derivations
		expect(second.slice(0, 2)).toEqual(first.slice(0, 2));
		expect(second[0]).toBe(first[0]);
		expect(second[1]).toBe(first[1]);

		// the streaming last turn recomputed: fresh section objects
		expect(second[second.length - 1]).not.toBe(first[first.length - 1]);
	});
});