package agent

import (
	"encoding/json"
	"testing"
)

func TestNewReturnsHermesBackend(t *testing.T) {
	t.Parallel()
	b, err := New("hermes", Config{ExecutablePath: "/nonexistent/hermes"})
	if err != nil {
		t.Fatalf("New(hermes) error: %v", err)
	}
	if _, ok := b.(*hermesBackend); !ok {
		t.Fatalf("expected *hermesBackend, got %T", b)
	}
}

// ── extractHermesSessionID ──

func TestExtractHermesSessionID(t *testing.T) {
	t.Parallel()
	raw := json.RawMessage(`{"sessionId":"20260410_141145_47260c"}`)
	got := extractHermesSessionID(raw)
	if got != "20260410_141145_47260c" {
		t.Errorf("got %q, want %q", got, "20260410_141145_47260c")
	}
}

func TestExtractHermesSessionIDEmpty(t *testing.T) {
	t.Parallel()
	raw := json.RawMessage(`{}`)
	got := extractHermesSessionID(raw)
	if got != "" {
		t.Errorf("got %q, want empty", got)
	}
}

func TestExtractHermesSessionIDInvalidJSON(t *testing.T) {
	t.Parallel()
	raw := json.RawMessage(`not json`)
	got := extractHermesSessionID(raw)
	if got != "" {
		t.Errorf("got %q, want empty", got)
	}
}

// ── hermesToolNameFromTitle ──

func TestHermesToolNameFromTitle(t *testing.T) {
	t.Parallel()
	tests := []struct {
		title string
		kind  string
		want  string
	}{
		{"terminal: ls -la", "execute", "terminal"},
		{"read: /tmp/foo.go", "read", "read_file"},
		{"write: /tmp/bar.go", "edit", "write_file"},
		{"patch (replace): /tmp/baz.go", "edit", "patch"},
		{"search: *.go", "search", "search_files"},
		{"web search: golang acp protocol", "fetch", "web_search"},
		{"extract: https://example.com", "fetch", "web_extract"},
		{"delegate: fix the bug", "execute", "delegate_task"},
		{"analyze image: what is this?", "read", "vision_analyze"},
		{"execute code", "execute", "execute_code"},
		// Fallback to kind when no colon in title.
		{"unknownTool", "read", "read_file"},
		{"unknownTool", "edit", "write_file"},
		{"unknownTool", "execute", "terminal"},
		{"unknownTool", "search", "search_files"},
		{"unknownTool", "fetch", "web_search"},
		{"unknownTool", "think", "thinking"},
		{"unknownTool", "other", "other"},
		// Tool with colon but not in known map.
		{"custom_tool: args", "other", "custom_tool"},
	}
	for _, tt := range tests {
		got := hermesToolNameFromTitle(tt.title, tt.kind)
		if got != tt.want {
			t.Errorf("hermesToolNameFromTitle(%q, %q) = %q, want %q", tt.title, tt.kind, got, tt.want)
		}
	}
}

// ── handleLine routing ──

func TestHermesClientHandleLineResponse(t *testing.T) {
	t.Parallel()

	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
	}
	pr := &pendingRPC{ch: make(chan rpcResult, 1), method: "session/new"}
	c.pending[1] = pr

	c.handleLine(`{"jsonrpc":"2.0","id":1,"result":{"sessionId":"ses_abc"}}`)

	res := <-pr.ch
	if res.err != nil {
		t.Fatalf("unexpected error: %v", res.err)
	}
	sid := extractHermesSessionID(res.result)
	if sid != "ses_abc" {
		t.Errorf("sessionId: got %q, want %q", sid, "ses_abc")
	}
}

func TestHermesClientHandleLineError(t *testing.T) {
	t.Parallel()

	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
	}
	pr := &pendingRPC{ch: make(chan rpcResult, 1), method: "initialize"}
	c.pending[0] = pr

	c.handleLine(`{"jsonrpc":"2.0","id":0,"error":{"code":-32600,"message":"bad request"}}`)

	res := <-pr.ch
	if res.err == nil {
		t.Fatal("expected error")
	}
	if got := res.err.Error(); got != "initialize: bad request (code=-32600)" {
		t.Errorf("error: got %q", got)
	}
}

// ── session/update notification handling ──

func TestHermesClientHandleAgentMessage(t *testing.T) {
	t.Parallel()

	var got Message
	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
		onMessage: func(msg Message) {
			got = msg
		},
	}

	line := `{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"ses_1","update":{"sessionUpdate":"agent_message_chunk","content":{"type":"text","text":"Hello world"}}}}`
	c.handleLine(line)

	if got.Type != MessageText {
		t.Errorf("type: got %v, want MessageText", got.Type)
	}
	if got.Content != "Hello world" {
		t.Errorf("content: got %q, want %q", got.Content, "Hello world")
	}
}

func TestHermesClientHandleAgentThought(t *testing.T) {
	t.Parallel()

	var got Message
	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
		onMessage: func(msg Message) {
			got = msg
		},
	}

	line := `{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"ses_1","update":{"sessionUpdate":"agent_thought_chunk","content":{"type":"text","text":"Let me think..."}}}}`
	c.handleLine(line)

	if got.Type != MessageThinking {
		t.Errorf("type: got %v, want MessageThinking", got.Type)
	}
	if got.Content != "Let me think..." {
		t.Errorf("content: got %q, want %q", got.Content, "Let me think...")
	}
}

func TestHermesClientHandleToolCallStart(t *testing.T) {
	t.Parallel()

	var got Message
	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
		onMessage: func(msg Message) {
			got = msg
		},
	}

	line := `{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"ses_1","update":{"sessionUpdate":"tool_call","toolCallId":"tc-abc123","title":"terminal: ls -la","kind":"execute","status":"pending","rawInput":{"command":"ls -la"}}}}`
	c.handleLine(line)

	if got.Type != MessageToolUse {
		t.Errorf("type: got %v, want MessageToolUse", got.Type)
	}
	if got.Tool != "terminal" {
		t.Errorf("tool: got %q, want %q", got.Tool, "terminal")
	}
	if got.CallID != "tc-abc123" {
		t.Errorf("callID: got %q, want %q", got.CallID, "tc-abc123")
	}
	if cmd, ok := got.Input["command"].(string); !ok || cmd != "ls -la" {
		t.Errorf("input.command: got %v", got.Input["command"])
	}
}

func TestHermesClientHandleToolCallComplete(t *testing.T) {
	t.Parallel()

	var got Message
	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
		onMessage: func(msg Message) {
			got = msg
		},
	}

	line := `{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"ses_1","update":{"sessionUpdate":"tool_call_update","toolCallId":"tc-abc123","status":"completed","kind":"execute","rawOutput":"file1.go\nfile2.go\n"}}}`
	c.handleLine(line)

	if got.Type != MessageToolResult {
		t.Errorf("type: got %v, want MessageToolResult", got.Type)
	}
	if got.CallID != "tc-abc123" {
		t.Errorf("callID: got %q, want %q", got.CallID, "tc-abc123")
	}
	if got.Output != "file1.go\nfile2.go\n" {
		t.Errorf("output: got %q", got.Output)
	}
}

func TestHermesClientHandleToolCallInProgressIgnored(t *testing.T) {
	t.Parallel()

	called := false
	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
		onMessage: func(msg Message) {
			called = true
		},
	}

	line := `{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"ses_1","update":{"sessionUpdate":"tool_call_update","toolCallId":"tc-abc123","status":"in_progress"}}}`
	c.handleLine(line)

	if called {
		t.Error("expected in_progress tool_call_update to be ignored")
	}
}

func TestHermesClientHandleUsageUpdate(t *testing.T) {
	t.Parallel()

	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
	}

	line := `{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"ses_1","update":{"sessionUpdate":"usage_update","usage":{"inputTokens":500,"outputTokens":200,"cachedReadTokens":100}}}}`
	c.handleLine(line)

	c.usageMu.Lock()
	defer c.usageMu.Unlock()

	if c.usage.InputTokens != 500 {
		t.Errorf("inputTokens: got %d, want 500", c.usage.InputTokens)
	}
	if c.usage.OutputTokens != 200 {
		t.Errorf("outputTokens: got %d, want 200", c.usage.OutputTokens)
	}
	if c.usage.CacheReadTokens != 100 {
		t.Errorf("cacheReadTokens: got %d, want 100", c.usage.CacheReadTokens)
	}
}

func TestHermesClientHandleUsageUpdateCumulative(t *testing.T) {
	t.Parallel()

	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
	}

	// First usage update.
	c.handleLine(`{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"ses_1","update":{"sessionUpdate":"usage_update","usage":{"inputTokens":100,"outputTokens":50}}}}`)

	// Second usage update with higher values (should take the max).
	c.handleLine(`{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"ses_1","update":{"sessionUpdate":"usage_update","usage":{"inputTokens":300,"outputTokens":120}}}}`)

	c.usageMu.Lock()
	defer c.usageMu.Unlock()

	if c.usage.InputTokens != 300 {
		t.Errorf("inputTokens: got %d, want 300", c.usage.InputTokens)
	}
	if c.usage.OutputTokens != 120 {
		t.Errorf("outputTokens: got %d, want 120", c.usage.OutputTokens)
	}
}

// ── extractPromptResult ──

func TestHermesClientExtractPromptResult(t *testing.T) {
	t.Parallel()

	var got hermesPromptResult
	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
		onPromptDone: func(result hermesPromptResult) {
			got = result
		},
	}

	data := json.RawMessage(`{"stopReason":"end_turn","usage":{"inputTokens":1000,"outputTokens":200,"cachedReadTokens":50}}`)
	c.extractPromptResult(data)

	if got.stopReason != "end_turn" {
		t.Errorf("stopReason: got %q, want %q", got.stopReason, "end_turn")
	}
	if got.usage.InputTokens != 1000 {
		t.Errorf("inputTokens: got %d, want 1000", got.usage.InputTokens)
	}
	if got.usage.OutputTokens != 200 {
		t.Errorf("outputTokens: got %d, want 200", got.usage.OutputTokens)
	}
	if got.usage.CacheReadTokens != 50 {
		t.Errorf("cacheReadTokens: got %d, want 50", got.usage.CacheReadTokens)
	}
}

func TestHermesClientExtractPromptResultNoUsage(t *testing.T) {
	t.Parallel()

	var got hermesPromptResult
	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
		onPromptDone: func(result hermesPromptResult) {
			got = result
		},
	}

	data := json.RawMessage(`{"stopReason":"cancelled"}`)
	c.extractPromptResult(data)

	if got.stopReason != "cancelled" {
		t.Errorf("stopReason: got %q, want %q", got.stopReason, "cancelled")
	}
	if got.usage.InputTokens != 0 {
		t.Errorf("inputTokens: got %d, want 0", got.usage.InputTokens)
	}
}

func TestHermesClientIgnoresUnknownNotification(t *testing.T) {
	t.Parallel()

	called := false
	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
		onMessage: func(msg Message) {
			called = true
		},
	}

	// Unknown method should be silently ignored.
	c.handleLine(`{"jsonrpc":"2.0","method":"unknown/event","params":{}}`)

	if called {
		t.Error("expected unknown notification to be ignored")
	}
}

func TestHermesClientIgnoresInvalidJSON(t *testing.T) {
	t.Parallel()

	c := &hermesClient{
		pending: make(map[int]*pendingRPC),
	}

	// Should not panic.
	c.handleLine("not json at all")
	c.handleLine("")
	c.handleLine("{}")
}