package job

import (
	"fmt"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"path/filepath"
	"testing"
	"time"

	"code.chimeric.al/chimerical/odidere/internal/config"
	"code.chimeric.al/chimerical/odidere/internal/conversation"
	"code.chimeric.al/chimerical/odidere/internal/db"
	"code.chimeric.al/chimerical/odidere/internal/llm"
	"code.chimeric.al/chimerical/odidere/internal/tool"
)

func testDependencies(t *testing.T) *llm.Client {
	t.Helper()

	client, err := llm.NewClient(
		llm.Config{URL: "http://localhost"}, slog.Default(),
	)
	if err != nil {
		t.Fatalf("llm.NewClient: %v", err)
	}
	return client
}

func TestConfigValidate(t *testing.T) {
	tests := []struct {
		name    string
		config  config.JobConfig
		wantErr bool
	}{
		{
			name:    "empty config",
			config:  config.JobConfig{},
			wantErr: true,
		},
		{
			name: "missing name",
			config: config.JobConfig{
				Schedule: "0 9 * * *",
				Task:     "do something",
				UserId:   "default",
			},
			wantErr: true,
		},
		{
			name: "missing task",
			config: config.JobConfig{
				Name:     "test",
				Schedule: "0 9 * * *",
				UserId:   "default",
			},
			wantErr: true,
		},
		{
			name: "missing schedule",
			config: config.JobConfig{
				Name:   "test",
				Task:   "do something",
				UserId: "default",
			},
			wantErr: true,
		},
		{
			name: "missing user ID",
			config: config.JobConfig{
				Name:     "test",
				Task:     "do something",
				Schedule: "0 9 * * *",
			},
			wantErr: true,
		},
		{
			name: "negative max iterations",
			config: config.JobConfig{
				Name:          "test",
				Task:          "do something",
				Schedule:      "0 9 * * *",
				MaxIterations: -1,
				UserId:        "default",
			},
			wantErr: true,
		},
		{
			name: "minimal valid config",
			config: config.JobConfig{
				Name:     "test",
				Task:     "do something",
				Schedule: "0 9 * * *",
				UserId:   "default",
			},
			wantErr: false,
		},
		{
			name: "full valid config",
			config: config.JobConfig{
				Name:          "test",
				Task:          "do something",
				Schedule:      "0 9 * * *",
				Timeout:       10 * time.Minute,
				MaxIterations: 20,
				SystemMessage: "You are an assistant.",
				UserId:        "default",
			},
			wantErr: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := tt.config.Validate()
			if (err != nil) != tt.wantErr {
				t.Errorf("Validate() error = %v, wantErr %v", err, tt.wantErr)
			}
		})
	}
}

func TestConfigMaxIterations(t *testing.T) {
	// Zero means unlimited
	cfg := config.JobConfig{Name: "test"}
	if got := cfg.MaxIterations; got != 0 {
		t.Errorf("default max iterations = %d, want 0", got)
	}

	cfg.MaxIterations = 0
	if got := cfg.MaxIterations; got != 0 {
		t.Errorf("explicit zero max iterations = %d, want 0", got)
	}

	// Positive value passes through
	cfg.MaxIterations = 25
	if got := cfg.MaxIterations; got != 25 {
		t.Errorf("custom max iterations = %d, want 25", got)
	}
}

func TestConfigTimeout(t *testing.T) {
	// A zero Timeout means the job has no per-job execution limit;
	// Run then relies on the callers context.
	var cfg config.JobConfig
	if cfg.Timeout != 0 {
		t.Errorf("default timeout = %v, want 0", cfg.Timeout)
	}
}

func TestNew(t *testing.T) {
	client := testDependencies(t)
	cfg := config.JobConfig{
		Name:          "test",
		Task:          "do something",
		Schedule:      "0 9 * * *",
		Timeout:       10 * time.Minute,
		MaxIterations: 20,
		SystemMessage: "You are an assistant.",
	}

	cfg.Model.Model = "test-model"
	cfg.UserId = "default"
	j, err := New(cfg, client, slog.Default())
	if err != nil {
		t.Fatalf("New() error = %v", err)
	}

	if j.Name() != "test" {
		t.Errorf("Name() = %q, want %q", j.Name(), "test")
	}
	if j.Schedule() != "0 9 * * *" {
		t.Errorf("Schedule() = %q, want %q", j.Schedule(), "0 9 * * *")
	}
	if j.SystemMessage() != "You are an assistant." {
		t.Errorf("SystemMessage() = %q, want %q", j.SystemMessage(), "You are an assistant.")
	}
	if j.Task() != "do something" {
		t.Errorf("Task() = %q, want %q", j.Task(), "do something")
	}
	if j.Timeout().Minutes() != 10 {
		t.Errorf("Timeout() = %v, want 10m", j.Timeout())
	}
	if j.MaxIterations() != 20 {
		t.Errorf("MaxIterations() = %d, want 20", j.MaxIterations())
	}
	if j.Model() != "test-model" {
		t.Errorf("Model() = %q, want %q", j.Model(), "test-model")
	}
	if j.Cron() == nil {
		t.Error("Cron() = nil, want non-nil")
	}
}

func TestNew_InvalidSchedule(t *testing.T) {
	client := testDependencies(t)
	cfg := config.JobConfig{
		Name:     "test",
		Task:     "do something",
		Schedule: "not-a-cron",
	}

	cfg.Model.Model = "test-model"
	cfg.UserId = "default"
	_, err := New(cfg, client, slog.Default())
	if err == nil {
		t.Fatal("New() expected error for invalid schedule")
	}
}

func TestNew_InvalidTimeout(t *testing.T) {
	client := testDependencies(t)
	cfg := config.JobConfig{
		Name:     "test",
		Task:     "do something",
		Schedule: "0 9 * * *",
		Timeout:  -time.Minute,
	}

	cfg.Model.Model = "test-model"
	cfg.UserId = "default"
	_, err := New(cfg, client, slog.Default())
	if err == nil {
		t.Fatal("New() expected error for invalid timeout")
	}
}

func TestNewRequiresDependencies(t *testing.T) {
	client := testDependencies(t)
	cfg := config.JobConfig{
		Name:     "test",
		Task:     "do something",
		Schedule: "0 9 * * *",
	}
	for _, test := range []struct {
		name   string
		client *llm.Client
		logger *slog.Logger
		userID string
	}{
		{
			name:   "empty user ID",
			client: client,
			logger: slog.Default(),
		},
		{
			name:   "nil llm client",
			logger: slog.Default(),
			userID: "default",
		},
		{
			name:   "nil logger",
			client: client,
			userID: "default",
		},
	} {
		t.Run(test.name, func(t *testing.T) {
			cfg.UserId = test.userID
			_, err := New(cfg, test.client, test.logger)
			if err == nil {
				t.Fatal("New() expected error")
			}
		})
	}
}

// TestRun checks that Run saves the task as a user message in the
// conversation and runs inference to completion.
func TestRun(t *testing.T) {
	var (
		ctx = t.Context()
		log = slog.New(slog.DiscardHandler)
	)
	inference := httptest.NewServer(http.HandlerFunc(func(
		w http.ResponseWriter, r *http.Request,
	) {
		w.Header().Set("Content-Type", "application/json")
		fmt.Fprint(w, `{
			"choices":[{
				"message":{"role":"assistant","content":"finished"},
				"finish_reason":"stop"
			}]
		}`)
	}))
	defer inference.Close()

	database, err := db.Connect(ctx, db.Config{
		Path: filepath.Join(t.TempDir(), "job.db"),
	})
	if err != nil {
		t.Fatalf("db.Connect: %v", err)
	}
	defer database.Close()
	if err := database.ApplySchema(ctx, log); err != nil {
		t.Fatalf("ApplySchema: %v", err)
	}
	saved, err := db.New(database.Writer).InsertConversation(
		ctx, db.InsertConversationParams{UserId: "default"},
	)
	if err != nil {
		t.Fatalf("InsertConversation: %v", err)
	}
	registry, err := tool.NewRegistry(nil)
	if err != nil {
		t.Fatalf("tool.NewRegistry: %v", err)
	}
	c, err := conversation.New(
		conversation.Config{Id: saved.Id}, database, log, registry,
	)
	if err != nil {
		t.Fatalf("conversation.New: %v", err)
	}
	client, err := llm.NewClient(
		llm.Config{Provider: "test", URL: inference.URL}, log,
	)
	if err != nil {
		t.Fatalf("llm.NewClient: %v", err)
	}
	j, err := New(config.JobConfig{
		Name:     "daily report",
		Task:     "prepare the report",
		Schedule: "0 9 * * *",
		Model:    config.ModelConfig{Model: "test-model"},
		UserId:   "default",
	}, client, log)
	if err != nil {
		t.Fatalf("New: %v", err)
	}

	if err := j.Run(ctx, c); err != nil {
		t.Fatalf("Run: %v", err)
	}

	rows, err := db.New(database.Reader).
		SelectMessagesConversationId(ctx, saved.Id)
	if err != nil {
		t.Fatalf("SelectMessagesConversationId: %v", err)
	}
	if len(rows) != 2 ||
		rows[0].Role != db.MessageRoleUser ||
		rows[1].Role != db.MessageRoleAssistant {
		t.Fatalf("saved rows = %v, want user then assistant", rows)
	}
}